Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-or-later
2 : /*
3 : * Linux I2C core
4 : *
5 : * Copyright (C) 1995-99 Simon G. Vogl
6 : * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7 : * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8 : * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 : *
10 : * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
11 : */
12 :
13 : #define pr_fmt(fmt) "i2c-core: " fmt
14 :
15 : #include <dt-bindings/i2c/i2c.h>
16 : #include <linux/acpi.h>
17 : #include <linux/clk/clk-conf.h>
18 : #include <linux/completion.h>
19 : #include <linux/delay.h>
20 : #include <linux/err.h>
21 : #include <linux/errno.h>
22 : #include <linux/gpio/consumer.h>
23 : #include <linux/i2c.h>
24 : #include <linux/i2c-smbus.h>
25 : #include <linux/idr.h>
26 : #include <linux/init.h>
27 : #include <linux/interrupt.h>
28 : #include <linux/irqflags.h>
29 : #include <linux/jump_label.h>
30 : #include <linux/kernel.h>
31 : #include <linux/module.h>
32 : #include <linux/mutex.h>
33 : #include <linux/of_device.h>
34 : #include <linux/of.h>
35 : #include <linux/of_irq.h>
36 : #include <linux/pinctrl/consumer.h>
37 : #include <linux/pinctrl/devinfo.h>
38 : #include <linux/pm_domain.h>
39 : #include <linux/pm_runtime.h>
40 : #include <linux/pm_wakeirq.h>
41 : #include <linux/property.h>
42 : #include <linux/rwsem.h>
43 : #include <linux/slab.h>
44 :
45 : #include "i2c-core.h"
46 :
47 : #define CREATE_TRACE_POINTS
48 : #include <trace/events/i2c.h>
49 :
50 : #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
51 : #define I2C_ADDR_OFFSET_SLAVE 0x1000
52 :
53 : #define I2C_ADDR_7BITS_MAX 0x77
54 : #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
55 :
56 : #define I2C_ADDR_DEVICE_ID 0x7c
57 :
58 : /*
59 : * core_lock protects i2c_adapter_idr, and guarantees that device detection,
60 : * deletion of detected devices are serialized
61 : */
62 : static DEFINE_MUTEX(core_lock);
63 : static DEFINE_IDR(i2c_adapter_idr);
64 :
65 : static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
66 :
67 : static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
68 : static bool is_registered;
69 :
70 0 : int i2c_transfer_trace_reg(void)
71 : {
72 0 : static_branch_inc(&i2c_trace_msg_key);
73 0 : return 0;
74 : }
75 :
76 0 : void i2c_transfer_trace_unreg(void)
77 : {
78 0 : static_branch_dec(&i2c_trace_msg_key);
79 0 : }
80 :
81 0 : const char *i2c_freq_mode_string(u32 bus_freq_hz)
82 : {
83 0 : switch (bus_freq_hz) {
84 : case I2C_MAX_STANDARD_MODE_FREQ:
85 : return "Standard Mode (100 kHz)";
86 : case I2C_MAX_FAST_MODE_FREQ:
87 0 : return "Fast Mode (400 kHz)";
88 : case I2C_MAX_FAST_MODE_PLUS_FREQ:
89 0 : return "Fast Mode Plus (1.0 MHz)";
90 : case I2C_MAX_TURBO_MODE_FREQ:
91 0 : return "Turbo Mode (1.4 MHz)";
92 : case I2C_MAX_HIGH_SPEED_MODE_FREQ:
93 0 : return "High Speed Mode (3.4 MHz)";
94 : case I2C_MAX_ULTRA_FAST_MODE_FREQ:
95 0 : return "Ultra Fast Mode (5.0 MHz)";
96 : default:
97 0 : return "Unknown Mode";
98 : }
99 : }
100 : EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
101 :
102 0 : const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
103 : const struct i2c_client *client)
104 : {
105 0 : if (!(id && client))
106 : return NULL;
107 :
108 0 : while (id->name[0]) {
109 0 : if (strcmp(client->name, id->name) == 0)
110 : return id;
111 0 : id++;
112 : }
113 : return NULL;
114 : }
115 : EXPORT_SYMBOL_GPL(i2c_match_id);
116 :
117 0 : static int i2c_device_match(struct device *dev, struct device_driver *drv)
118 : {
119 0 : struct i2c_client *client = i2c_verify_client(dev);
120 : struct i2c_driver *driver;
121 :
122 :
123 : /* Attempt an OF style match */
124 0 : if (i2c_of_match_device(drv->of_match_table, client))
125 : return 1;
126 :
127 : /* Then ACPI style match */
128 0 : if (acpi_driver_match_device(dev, drv))
129 : return 1;
130 :
131 0 : driver = to_i2c_driver(drv);
132 :
133 : /* Finally an I2C match */
134 0 : if (i2c_match_id(driver->id_table, client))
135 : return 1;
136 :
137 0 : return 0;
138 : }
139 :
140 0 : static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
141 : {
142 0 : const struct i2c_client *client = to_i2c_client(dev);
143 : int rc;
144 :
145 0 : rc = of_device_uevent_modalias(dev, env);
146 : if (rc != -ENODEV)
147 : return rc;
148 :
149 0 : rc = acpi_device_uevent_modalias(dev, env);
150 : if (rc != -ENODEV)
151 : return rc;
152 :
153 0 : return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
154 : }
155 :
156 : /* i2c bus recovery routines */
157 0 : static int get_scl_gpio_value(struct i2c_adapter *adap)
158 : {
159 0 : return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
160 : }
161 :
162 0 : static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
163 : {
164 0 : gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
165 0 : }
166 :
167 0 : static int get_sda_gpio_value(struct i2c_adapter *adap)
168 : {
169 0 : return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
170 : }
171 :
172 : static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
173 : {
174 : gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
175 : }
176 :
177 0 : static int i2c_generic_bus_free(struct i2c_adapter *adap)
178 : {
179 0 : struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
180 0 : int ret = -EOPNOTSUPP;
181 :
182 0 : if (bri->get_bus_free)
183 0 : ret = bri->get_bus_free(adap);
184 0 : else if (bri->get_sda)
185 0 : ret = bri->get_sda(adap);
186 :
187 0 : if (ret < 0)
188 : return ret;
189 :
190 0 : return ret ? 0 : -EBUSY;
191 : }
192 :
193 : /*
194 : * We are generating clock pulses. ndelay() determines durating of clk pulses.
195 : * We will generate clock with rate 100 KHz and so duration of both clock levels
196 : * is: delay in ns = (10^6 / 100) / 2
197 : */
198 : #define RECOVERY_NDELAY 5000
199 : #define RECOVERY_CLK_CNT 9
200 :
201 0 : int i2c_generic_scl_recovery(struct i2c_adapter *adap)
202 : {
203 0 : struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
204 0 : int i = 0, scl = 1, ret = 0;
205 :
206 0 : if (bri->prepare_recovery)
207 0 : bri->prepare_recovery(adap);
208 0 : if (bri->pinctrl)
209 : pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
210 :
211 : /*
212 : * If we can set SDA, we will always create a STOP to ensure additional
213 : * pulses will do no harm. This is achieved by letting SDA follow SCL
214 : * half a cycle later. Check the 'incomplete_write_byte' fault injector
215 : * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
216 : * here for simplicity.
217 : */
218 0 : bri->set_scl(adap, scl);
219 0 : ndelay(RECOVERY_NDELAY);
220 0 : if (bri->set_sda)
221 0 : bri->set_sda(adap, scl);
222 : ndelay(RECOVERY_NDELAY / 2);
223 :
224 : /*
225 : * By this time SCL is high, as we need to give 9 falling-rising edges
226 : */
227 0 : while (i++ < RECOVERY_CLK_CNT * 2) {
228 0 : if (scl) {
229 : /* SCL shouldn't be low here */
230 0 : if (!bri->get_scl(adap)) {
231 0 : dev_err(&adap->dev,
232 : "SCL is stuck low, exit recovery\n");
233 0 : ret = -EBUSY;
234 0 : break;
235 : }
236 : }
237 :
238 0 : scl = !scl;
239 0 : bri->set_scl(adap, scl);
240 : /* Creating STOP again, see above */
241 0 : if (scl) {
242 : /* Honour minimum tsu:sto */
243 : ndelay(RECOVERY_NDELAY);
244 : } else {
245 : /* Honour minimum tf and thd:dat */
246 : ndelay(RECOVERY_NDELAY / 2);
247 : }
248 0 : if (bri->set_sda)
249 0 : bri->set_sda(adap, scl);
250 0 : ndelay(RECOVERY_NDELAY / 2);
251 :
252 0 : if (scl) {
253 0 : ret = i2c_generic_bus_free(adap);
254 0 : if (ret == 0)
255 : break;
256 : }
257 : }
258 :
259 : /* If we can't check bus status, assume recovery worked */
260 0 : if (ret == -EOPNOTSUPP)
261 0 : ret = 0;
262 :
263 0 : if (bri->unprepare_recovery)
264 0 : bri->unprepare_recovery(adap);
265 0 : if (bri->pinctrl)
266 : pinctrl_select_state(bri->pinctrl, bri->pins_default);
267 :
268 0 : return ret;
269 : }
270 : EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
271 :
272 0 : int i2c_recover_bus(struct i2c_adapter *adap)
273 : {
274 0 : if (!adap->bus_recovery_info)
275 : return -EBUSY;
276 :
277 : dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
278 0 : return adap->bus_recovery_info->recover_bus(adap);
279 : }
280 : EXPORT_SYMBOL_GPL(i2c_recover_bus);
281 :
282 0 : static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
283 : {
284 0 : struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
285 0 : struct device *dev = &adap->dev;
286 0 : struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
287 :
288 0 : bri->pinctrl = p;
289 :
290 : /*
291 : * we can't change states without pinctrl, so remove the states if
292 : * populated
293 : */
294 0 : if (!p) {
295 0 : bri->pins_default = NULL;
296 0 : bri->pins_gpio = NULL;
297 0 : return;
298 : }
299 :
300 0 : if (!bri->pins_default) {
301 0 : bri->pins_default = pinctrl_lookup_state(p,
302 : PINCTRL_STATE_DEFAULT);
303 0 : if (IS_ERR(bri->pins_default)) {
304 : dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
305 : bri->pins_default = NULL;
306 : }
307 : }
308 0 : if (!bri->pins_gpio) {
309 0 : bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
310 0 : if (IS_ERR(bri->pins_gpio))
311 : bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
312 :
313 0 : if (IS_ERR(bri->pins_gpio)) {
314 : dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
315 : bri->pins_gpio = NULL;
316 : }
317 : }
318 :
319 : /* for pinctrl state changes, we need all the information */
320 0 : if (bri->pins_default && bri->pins_gpio) {
321 0 : dev_info(dev, "using pinctrl states for GPIO recovery");
322 : } else {
323 0 : bri->pinctrl = NULL;
324 0 : bri->pins_default = NULL;
325 0 : bri->pins_gpio = NULL;
326 : }
327 : }
328 :
329 0 : static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
330 : {
331 0 : struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
332 0 : struct device *dev = &adap->dev;
333 : struct gpio_desc *gpiod;
334 0 : int ret = 0;
335 :
336 : /*
337 : * don't touch the recovery information if the driver is not using
338 : * generic SCL recovery
339 : */
340 0 : if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
341 : return 0;
342 :
343 : /*
344 : * pins might be taken as GPIO, so we should inform pinctrl about
345 : * this and move the state to GPIO
346 : */
347 0 : if (bri->pinctrl)
348 : pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
349 :
350 : /*
351 : * if there is incomplete or no recovery information, see if generic
352 : * GPIO recovery is available
353 : */
354 0 : if (!bri->scl_gpiod) {
355 : gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
356 : if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
357 : ret = -EPROBE_DEFER;
358 : goto cleanup_pinctrl_state;
359 : }
360 : if (!IS_ERR(gpiod)) {
361 : bri->scl_gpiod = gpiod;
362 : bri->recover_bus = i2c_generic_scl_recovery;
363 : dev_info(dev, "using generic GPIOs for recovery\n");
364 : }
365 : }
366 :
367 : /* SDA GPIOD line is optional, so we care about DEFER only */
368 0 : if (!bri->sda_gpiod) {
369 : /*
370 : * We have SCL. Pull SCL low and wait a bit so that SDA glitches
371 : * have no effect.
372 : */
373 0 : gpiod_direction_output(bri->scl_gpiod, 0);
374 0 : udelay(10);
375 0 : gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
376 :
377 : /* Wait a bit in case of a SDA glitch, and then release SCL. */
378 0 : udelay(10);
379 0 : gpiod_direction_output(bri->scl_gpiod, 1);
380 :
381 : if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
382 : ret = -EPROBE_DEFER;
383 : goto cleanup_pinctrl_state;
384 : }
385 : if (!IS_ERR(gpiod))
386 : bri->sda_gpiod = gpiod;
387 : }
388 :
389 : cleanup_pinctrl_state:
390 : /* change the state of the pins back to their default state */
391 0 : if (bri->pinctrl)
392 : pinctrl_select_state(bri->pinctrl, bri->pins_default);
393 :
394 : return ret;
395 : }
396 :
397 : static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
398 : {
399 0 : i2c_gpio_init_pinctrl_recovery(adap);
400 0 : return i2c_gpio_init_generic_recovery(adap);
401 : }
402 :
403 0 : static int i2c_init_recovery(struct i2c_adapter *adap)
404 : {
405 0 : struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
406 0 : bool is_error_level = true;
407 : char *err_str;
408 :
409 0 : if (!bri)
410 : return 0;
411 :
412 0 : if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
413 : return -EPROBE_DEFER;
414 :
415 0 : if (!bri->recover_bus) {
416 : err_str = "no suitable method provided";
417 : is_error_level = false;
418 : goto err;
419 : }
420 :
421 0 : if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
422 0 : bri->get_scl = get_scl_gpio_value;
423 0 : bri->set_scl = set_scl_gpio_value;
424 0 : if (bri->sda_gpiod) {
425 0 : bri->get_sda = get_sda_gpio_value;
426 : /* FIXME: add proper flag instead of '0' once available */
427 0 : if (gpiod_get_direction(bri->sda_gpiod) == 0)
428 : bri->set_sda = set_sda_gpio_value;
429 : }
430 0 : } else if (bri->recover_bus == i2c_generic_scl_recovery) {
431 : /* Generic SCL recovery */
432 0 : if (!bri->set_scl || !bri->get_scl) {
433 : err_str = "no {get|set}_scl() found";
434 : goto err;
435 : }
436 0 : if (!bri->set_sda && !bri->get_sda) {
437 : err_str = "either get_sda() or set_sda() needed";
438 : goto err;
439 : }
440 : }
441 :
442 : return 0;
443 : err:
444 0 : if (is_error_level)
445 0 : dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
446 : else
447 : dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
448 0 : adap->bus_recovery_info = NULL;
449 :
450 0 : return -EINVAL;
451 : }
452 :
453 0 : static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
454 : {
455 0 : struct i2c_adapter *adap = client->adapter;
456 : unsigned int irq;
457 :
458 0 : if (!adap->host_notify_domain)
459 : return -ENXIO;
460 :
461 0 : if (client->flags & I2C_CLIENT_TEN)
462 : return -EINVAL;
463 :
464 0 : irq = irq_create_mapping(adap->host_notify_domain, client->addr);
465 :
466 0 : return irq > 0 ? irq : -ENXIO;
467 : }
468 :
469 0 : static int i2c_device_probe(struct device *dev)
470 : {
471 0 : struct i2c_client *client = i2c_verify_client(dev);
472 : struct i2c_driver *driver;
473 : bool do_power_on;
474 : int status;
475 :
476 0 : if (!client)
477 : return 0;
478 :
479 0 : client->irq = client->init_irq;
480 :
481 0 : if (!client->irq) {
482 0 : int irq = -ENOENT;
483 :
484 0 : if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
485 : dev_dbg(dev, "Using Host Notify IRQ\n");
486 : /* Keep adapter active when Host Notify is required */
487 0 : pm_runtime_get_sync(&client->adapter->dev);
488 0 : irq = i2c_smbus_host_notify_to_irq(client);
489 0 : } else if (dev->of_node) {
490 0 : irq = of_irq_get_byname(dev->of_node, "irq");
491 : if (irq == -EINVAL || irq == -ENODATA)
492 : irq = of_irq_get(dev->of_node, 0);
493 : } else if (ACPI_COMPANION(dev)) {
494 : bool wake_capable;
495 :
496 : irq = i2c_acpi_get_irq(client, &wake_capable);
497 : if (irq > 0 && wake_capable)
498 : client->flags |= I2C_CLIENT_WAKE;
499 : }
500 0 : if (irq == -EPROBE_DEFER) {
501 : status = irq;
502 : goto put_sync_adapter;
503 : }
504 :
505 0 : if (irq < 0)
506 0 : irq = 0;
507 :
508 0 : client->irq = irq;
509 : }
510 :
511 0 : driver = to_i2c_driver(dev->driver);
512 :
513 : /*
514 : * An I2C ID table is not mandatory, if and only if, a suitable OF
515 : * or ACPI ID table is supplied for the probing device.
516 : */
517 0 : if (!driver->id_table &&
518 : !acpi_driver_match_device(dev, dev->driver) &&
519 : !i2c_of_match_device(dev->driver->of_match_table, client)) {
520 : status = -ENODEV;
521 : goto put_sync_adapter;
522 : }
523 :
524 0 : if (client->flags & I2C_CLIENT_WAKE) {
525 : int wakeirq;
526 :
527 0 : wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
528 : if (wakeirq == -EPROBE_DEFER) {
529 : status = wakeirq;
530 : goto put_sync_adapter;
531 : }
532 :
533 0 : device_init_wakeup(&client->dev, true);
534 :
535 : if (wakeirq > 0 && wakeirq != client->irq)
536 : status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
537 0 : else if (client->irq > 0)
538 0 : status = dev_pm_set_wake_irq(dev, client->irq);
539 : else
540 : status = 0;
541 :
542 0 : if (status)
543 0 : dev_warn(&client->dev, "failed to set up wakeup irq\n");
544 : }
545 :
546 : dev_dbg(dev, "probe\n");
547 :
548 0 : status = of_clk_set_defaults(dev->of_node, false);
549 : if (status < 0)
550 : goto err_clear_wakeup_irq;
551 :
552 0 : do_power_on = !i2c_acpi_waive_d0_probe(dev);
553 0 : status = dev_pm_domain_attach(&client->dev, do_power_on);
554 0 : if (status)
555 : goto err_clear_wakeup_irq;
556 :
557 0 : client->devres_group_id = devres_open_group(&client->dev, NULL,
558 : GFP_KERNEL);
559 0 : if (!client->devres_group_id) {
560 : status = -ENOMEM;
561 : goto err_detach_pm_domain;
562 : }
563 :
564 0 : if (driver->probe)
565 0 : status = driver->probe(client);
566 : else
567 : status = -EINVAL;
568 :
569 : /*
570 : * Note that we are not closing the devres group opened above so
571 : * even resources that were attached to the device after probe is
572 : * run are released when i2c_device_remove() is executed. This is
573 : * needed as some drivers would allocate additional resources,
574 : * for example when updating firmware.
575 : */
576 :
577 0 : if (status)
578 : goto err_release_driver_resources;
579 :
580 : return 0;
581 :
582 : err_release_driver_resources:
583 0 : devres_release_group(&client->dev, client->devres_group_id);
584 : err_detach_pm_domain:
585 0 : dev_pm_domain_detach(&client->dev, do_power_on);
586 : err_clear_wakeup_irq:
587 0 : dev_pm_clear_wake_irq(&client->dev);
588 0 : device_init_wakeup(&client->dev, false);
589 : put_sync_adapter:
590 0 : if (client->flags & I2C_CLIENT_HOST_NOTIFY)
591 0 : pm_runtime_put_sync(&client->adapter->dev);
592 :
593 : return status;
594 : }
595 :
596 0 : static void i2c_device_remove(struct device *dev)
597 : {
598 0 : struct i2c_client *client = to_i2c_client(dev);
599 : struct i2c_driver *driver;
600 :
601 0 : driver = to_i2c_driver(dev->driver);
602 0 : if (driver->remove) {
603 : dev_dbg(dev, "remove\n");
604 :
605 0 : driver->remove(client);
606 : }
607 :
608 0 : devres_release_group(&client->dev, client->devres_group_id);
609 :
610 0 : dev_pm_domain_detach(&client->dev, true);
611 :
612 0 : dev_pm_clear_wake_irq(&client->dev);
613 0 : device_init_wakeup(&client->dev, false);
614 :
615 0 : client->irq = 0;
616 0 : if (client->flags & I2C_CLIENT_HOST_NOTIFY)
617 0 : pm_runtime_put(&client->adapter->dev);
618 0 : }
619 :
620 0 : static void i2c_device_shutdown(struct device *dev)
621 : {
622 0 : struct i2c_client *client = i2c_verify_client(dev);
623 : struct i2c_driver *driver;
624 :
625 0 : if (!client || !dev->driver)
626 : return;
627 0 : driver = to_i2c_driver(dev->driver);
628 0 : if (driver->shutdown)
629 0 : driver->shutdown(client);
630 0 : else if (client->irq > 0)
631 0 : disable_irq(client->irq);
632 : }
633 :
634 0 : static void i2c_client_dev_release(struct device *dev)
635 : {
636 0 : kfree(to_i2c_client(dev));
637 0 : }
638 :
639 : static ssize_t
640 0 : name_show(struct device *dev, struct device_attribute *attr, char *buf)
641 : {
642 0 : return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
643 0 : to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
644 : }
645 : static DEVICE_ATTR_RO(name);
646 :
647 : static ssize_t
648 0 : modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
649 : {
650 0 : struct i2c_client *client = to_i2c_client(dev);
651 : int len;
652 :
653 0 : len = of_device_modalias(dev, buf, PAGE_SIZE);
654 : if (len != -ENODEV)
655 : return len;
656 :
657 0 : len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
658 : if (len != -ENODEV)
659 : return len;
660 :
661 0 : return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
662 : }
663 : static DEVICE_ATTR_RO(modalias);
664 :
665 : static struct attribute *i2c_dev_attrs[] = {
666 : &dev_attr_name.attr,
667 : /* modalias helps coldplug: modprobe $(cat .../modalias) */
668 : &dev_attr_modalias.attr,
669 : NULL
670 : };
671 : ATTRIBUTE_GROUPS(i2c_dev);
672 :
673 : struct bus_type i2c_bus_type = {
674 : .name = "i2c",
675 : .match = i2c_device_match,
676 : .probe = i2c_device_probe,
677 : .remove = i2c_device_remove,
678 : .shutdown = i2c_device_shutdown,
679 : };
680 : EXPORT_SYMBOL_GPL(i2c_bus_type);
681 :
682 : struct device_type i2c_client_type = {
683 : .groups = i2c_dev_groups,
684 : .uevent = i2c_device_uevent,
685 : .release = i2c_client_dev_release,
686 : };
687 : EXPORT_SYMBOL_GPL(i2c_client_type);
688 :
689 :
690 : /**
691 : * i2c_verify_client - return parameter as i2c_client, or NULL
692 : * @dev: device, probably from some driver model iterator
693 : *
694 : * When traversing the driver model tree, perhaps using driver model
695 : * iterators like @device_for_each_child(), you can't assume very much
696 : * about the nodes you find. Use this function to avoid oopses caused
697 : * by wrongly treating some non-I2C device as an i2c_client.
698 : */
699 0 : struct i2c_client *i2c_verify_client(struct device *dev)
700 : {
701 0 : return (dev->type == &i2c_client_type)
702 0 : ? to_i2c_client(dev)
703 0 : : NULL;
704 : }
705 : EXPORT_SYMBOL(i2c_verify_client);
706 :
707 :
708 : /* Return a unique address which takes the flags of the client into account */
709 : static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
710 : {
711 0 : unsigned short addr = client->addr;
712 :
713 : /* For some client flags, add an arbitrary offset to avoid collisions */
714 0 : if (client->flags & I2C_CLIENT_TEN)
715 0 : addr |= I2C_ADDR_OFFSET_TEN_BIT;
716 :
717 0 : if (client->flags & I2C_CLIENT_SLAVE)
718 0 : addr |= I2C_ADDR_OFFSET_SLAVE;
719 :
720 : return addr;
721 : }
722 :
723 : /* This is a permissive address validity check, I2C address map constraints
724 : * are purposely not enforced, except for the general call address. */
725 : static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
726 : {
727 0 : if (flags & I2C_CLIENT_TEN) {
728 : /* 10-bit address, all values are valid */
729 0 : if (addr > 0x3ff)
730 : return -EINVAL;
731 : } else {
732 : /* 7-bit address, reject the general call address */
733 0 : if (addr == 0x00 || addr > 0x7f)
734 : return -EINVAL;
735 : }
736 : return 0;
737 : }
738 :
739 : /* And this is a strict address validity check, used when probing. If a
740 : * device uses a reserved address, then it shouldn't be probed. 7-bit
741 : * addressing is assumed, 10-bit address devices are rare and should be
742 : * explicitly enumerated. */
743 0 : int i2c_check_7bit_addr_validity_strict(unsigned short addr)
744 : {
745 : /*
746 : * Reserved addresses per I2C specification:
747 : * 0x00 General call address / START byte
748 : * 0x01 CBUS address
749 : * 0x02 Reserved for different bus format
750 : * 0x03 Reserved for future purposes
751 : * 0x04-0x07 Hs-mode master code
752 : * 0x78-0x7b 10-bit slave addressing
753 : * 0x7c-0x7f Reserved for future purposes
754 : */
755 0 : if (addr < 0x08 || addr > 0x77)
756 : return -EINVAL;
757 0 : return 0;
758 : }
759 :
760 : static int __i2c_check_addr_busy(struct device *dev, void *addrp)
761 : {
762 0 : struct i2c_client *client = i2c_verify_client(dev);
763 0 : int addr = *(int *)addrp;
764 :
765 0 : if (client && i2c_encode_flags_to_addr(client) == addr)
766 : return -EBUSY;
767 : return 0;
768 : }
769 :
770 : /* walk up mux tree */
771 : static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
772 : {
773 : struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
774 : int result;
775 :
776 : result = device_for_each_child(&adapter->dev, &addr,
777 : __i2c_check_addr_busy);
778 :
779 : if (!result && parent)
780 : result = i2c_check_mux_parents(parent, addr);
781 :
782 : return result;
783 : }
784 :
785 : /* recurse down mux tree */
786 0 : static int i2c_check_mux_children(struct device *dev, void *addrp)
787 : {
788 : int result;
789 :
790 0 : if (dev->type == &i2c_adapter_type)
791 0 : result = device_for_each_child(dev, addrp,
792 : i2c_check_mux_children);
793 : else
794 : result = __i2c_check_addr_busy(dev, addrp);
795 :
796 0 : return result;
797 : }
798 :
799 : static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
800 : {
801 0 : struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
802 0 : int result = 0;
803 :
804 : if (parent)
805 : result = i2c_check_mux_parents(parent, addr);
806 :
807 : if (!result)
808 0 : result = device_for_each_child(&adapter->dev, &addr,
809 : i2c_check_mux_children);
810 :
811 : return result;
812 : }
813 :
814 : /**
815 : * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
816 : * @adapter: Target I2C bus segment
817 : * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
818 : * locks only this branch in the adapter tree
819 : */
820 0 : static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
821 : unsigned int flags)
822 : {
823 0 : rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
824 0 : }
825 :
826 : /**
827 : * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
828 : * @adapter: Target I2C bus segment
829 : * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
830 : * trylocks only this branch in the adapter tree
831 : */
832 0 : static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
833 : unsigned int flags)
834 : {
835 0 : return rt_mutex_trylock(&adapter->bus_lock);
836 : }
837 :
838 : /**
839 : * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
840 : * @adapter: Target I2C bus segment
841 : * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
842 : * unlocks only this branch in the adapter tree
843 : */
844 0 : static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
845 : unsigned int flags)
846 : {
847 0 : rt_mutex_unlock(&adapter->bus_lock);
848 0 : }
849 :
850 0 : static void i2c_dev_set_name(struct i2c_adapter *adap,
851 : struct i2c_client *client,
852 : struct i2c_board_info const *info)
853 : {
854 0 : struct acpi_device *adev = ACPI_COMPANION(&client->dev);
855 :
856 0 : if (info && info->dev_name) {
857 0 : dev_set_name(&client->dev, "i2c-%s", info->dev_name);
858 0 : return;
859 : }
860 :
861 : if (adev) {
862 : dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
863 : return;
864 : }
865 :
866 0 : dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
867 0 : i2c_encode_flags_to_addr(client));
868 : }
869 :
870 0 : int i2c_dev_irq_from_resources(const struct resource *resources,
871 : unsigned int num_resources)
872 : {
873 : struct irq_data *irqd;
874 : int i;
875 :
876 0 : for (i = 0; i < num_resources; i++) {
877 0 : const struct resource *r = &resources[i];
878 :
879 0 : if (resource_type(r) != IORESOURCE_IRQ)
880 0 : continue;
881 :
882 0 : if (r->flags & IORESOURCE_BITS) {
883 0 : irqd = irq_get_irq_data(r->start);
884 0 : if (!irqd)
885 : break;
886 :
887 0 : irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
888 : }
889 :
890 0 : return r->start;
891 : }
892 :
893 : return 0;
894 : }
895 :
896 : /**
897 : * i2c_new_client_device - instantiate an i2c device
898 : * @adap: the adapter managing the device
899 : * @info: describes one I2C device; bus_num is ignored
900 : * Context: can sleep
901 : *
902 : * Create an i2c device. Binding is handled through driver model
903 : * probe()/remove() methods. A driver may be bound to this device when we
904 : * return from this function, or any later moment (e.g. maybe hotplugging will
905 : * load the driver module). This call is not appropriate for use by mainboard
906 : * initialization logic, which usually runs during an arch_initcall() long
907 : * before any i2c_adapter could exist.
908 : *
909 : * This returns the new i2c client, which may be saved for later use with
910 : * i2c_unregister_device(); or an ERR_PTR to describe the error.
911 : */
912 : struct i2c_client *
913 0 : i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
914 : {
915 : struct i2c_client *client;
916 : int status;
917 :
918 0 : client = kzalloc(sizeof *client, GFP_KERNEL);
919 0 : if (!client)
920 : return ERR_PTR(-ENOMEM);
921 :
922 0 : client->adapter = adap;
923 :
924 0 : client->dev.platform_data = info->platform_data;
925 0 : client->flags = info->flags;
926 0 : client->addr = info->addr;
927 :
928 0 : client->init_irq = info->irq;
929 0 : if (!client->init_irq)
930 0 : client->init_irq = i2c_dev_irq_from_resources(info->resources,
931 : info->num_resources);
932 :
933 0 : strscpy(client->name, info->type, sizeof(client->name));
934 :
935 0 : status = i2c_check_addr_validity(client->addr, client->flags);
936 0 : if (status) {
937 0 : dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
938 : client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
939 0 : goto out_err_silent;
940 : }
941 :
942 : /* Check for address business */
943 0 : status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
944 0 : if (status)
945 : goto out_err;
946 :
947 0 : client->dev.parent = &client->adapter->dev;
948 0 : client->dev.bus = &i2c_bus_type;
949 0 : client->dev.type = &i2c_client_type;
950 0 : client->dev.of_node = of_node_get(info->of_node);
951 0 : client->dev.fwnode = info->fwnode;
952 :
953 0 : device_enable_async_suspend(&client->dev);
954 0 : i2c_dev_set_name(adap, client, info);
955 :
956 0 : if (info->swnode) {
957 0 : status = device_add_software_node(&client->dev, info->swnode);
958 0 : if (status) {
959 0 : dev_err(&adap->dev,
960 : "Failed to add software node to client %s: %d\n",
961 : client->name, status);
962 0 : goto out_err_put_of_node;
963 : }
964 : }
965 :
966 0 : status = device_register(&client->dev);
967 0 : if (status)
968 : goto out_remove_swnode;
969 :
970 : dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
971 : client->name, dev_name(&client->dev));
972 :
973 : return client;
974 :
975 : out_remove_swnode:
976 0 : device_remove_software_node(&client->dev);
977 : out_err_put_of_node:
978 0 : of_node_put(info->of_node);
979 : out_err:
980 0 : dev_err(&adap->dev,
981 : "Failed to register i2c client %s at 0x%02x (%d)\n",
982 : client->name, client->addr, status);
983 : out_err_silent:
984 0 : kfree(client);
985 0 : return ERR_PTR(status);
986 : }
987 : EXPORT_SYMBOL_GPL(i2c_new_client_device);
988 :
989 : /**
990 : * i2c_unregister_device - reverse effect of i2c_new_*_device()
991 : * @client: value returned from i2c_new_*_device()
992 : * Context: can sleep
993 : */
994 0 : void i2c_unregister_device(struct i2c_client *client)
995 : {
996 0 : if (IS_ERR_OR_NULL(client))
997 : return;
998 :
999 : if (client->dev.of_node) {
1000 : of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1001 : of_node_put(client->dev.of_node);
1002 : }
1003 :
1004 : if (ACPI_COMPANION(&client->dev))
1005 : acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1006 0 : device_remove_software_node(&client->dev);
1007 0 : device_unregister(&client->dev);
1008 : }
1009 : EXPORT_SYMBOL_GPL(i2c_unregister_device);
1010 :
1011 : /**
1012 : * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1013 : * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1014 : *
1015 : * Look up and return the &struct i2c_client corresponding to the @fwnode.
1016 : * If no client can be found, or @fwnode is NULL, this returns NULL.
1017 : *
1018 : * The user must call put_device(&client->dev) once done with the i2c client.
1019 : */
1020 0 : struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1021 : {
1022 : struct i2c_client *client;
1023 : struct device *dev;
1024 :
1025 0 : if (!fwnode)
1026 : return NULL;
1027 :
1028 0 : dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1029 0 : if (!dev)
1030 : return NULL;
1031 :
1032 0 : client = i2c_verify_client(dev);
1033 0 : if (!client)
1034 0 : put_device(dev);
1035 :
1036 : return client;
1037 : }
1038 : EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1039 :
1040 :
1041 : static const struct i2c_device_id dummy_id[] = {
1042 : { "dummy", 0 },
1043 : { },
1044 : };
1045 :
1046 0 : static int dummy_probe(struct i2c_client *client)
1047 : {
1048 0 : return 0;
1049 : }
1050 :
1051 : static struct i2c_driver dummy_driver = {
1052 : .driver.name = "dummy",
1053 : .probe = dummy_probe,
1054 : .id_table = dummy_id,
1055 : };
1056 :
1057 : /**
1058 : * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1059 : * @adapter: the adapter managing the device
1060 : * @address: seven bit address to be used
1061 : * Context: can sleep
1062 : *
1063 : * This returns an I2C client bound to the "dummy" driver, intended for use
1064 : * with devices that consume multiple addresses. Examples of such chips
1065 : * include various EEPROMS (like 24c04 and 24c08 models).
1066 : *
1067 : * These dummy devices have two main uses. First, most I2C and SMBus calls
1068 : * except i2c_transfer() need a client handle; the dummy will be that handle.
1069 : * And second, this prevents the specified address from being bound to a
1070 : * different driver.
1071 : *
1072 : * This returns the new i2c client, which should be saved for later use with
1073 : * i2c_unregister_device(); or an ERR_PTR to describe the error.
1074 : */
1075 0 : struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1076 : {
1077 0 : struct i2c_board_info info = {
1078 : I2C_BOARD_INFO("dummy", address),
1079 : };
1080 :
1081 0 : return i2c_new_client_device(adapter, &info);
1082 : }
1083 : EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1084 :
1085 0 : static void devm_i2c_release_dummy(void *client)
1086 : {
1087 0 : i2c_unregister_device(client);
1088 0 : }
1089 :
1090 : /**
1091 : * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1092 : * @dev: device the managed resource is bound to
1093 : * @adapter: the adapter managing the device
1094 : * @address: seven bit address to be used
1095 : * Context: can sleep
1096 : *
1097 : * This is the device-managed version of @i2c_new_dummy_device. It returns the
1098 : * new i2c client or an ERR_PTR in case of an error.
1099 : */
1100 0 : struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1101 : struct i2c_adapter *adapter,
1102 : u16 address)
1103 : {
1104 : struct i2c_client *client;
1105 : int ret;
1106 :
1107 0 : client = i2c_new_dummy_device(adapter, address);
1108 0 : if (IS_ERR(client))
1109 : return client;
1110 :
1111 0 : ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1112 0 : if (ret)
1113 0 : return ERR_PTR(ret);
1114 :
1115 : return client;
1116 : }
1117 : EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1118 :
1119 : /**
1120 : * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1121 : * and create the associated device
1122 : * @client: Handle to the primary client
1123 : * @name: Handle to specify which secondary address to get
1124 : * @default_addr: Used as a fallback if no secondary address was specified
1125 : * Context: can sleep
1126 : *
1127 : * I2C clients can be composed of multiple I2C slaves bound together in a single
1128 : * component. The I2C client driver then binds to the master I2C slave and needs
1129 : * to create I2C dummy clients to communicate with all the other slaves.
1130 : *
1131 : * This function creates and returns an I2C dummy client whose I2C address is
1132 : * retrieved from the platform firmware based on the given slave name. If no
1133 : * address is specified by the firmware default_addr is used.
1134 : *
1135 : * On DT-based platforms the address is retrieved from the "reg" property entry
1136 : * cell whose "reg-names" value matches the slave name.
1137 : *
1138 : * This returns the new i2c client, which should be saved for later use with
1139 : * i2c_unregister_device(); or an ERR_PTR to describe the error.
1140 : */
1141 0 : struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1142 : const char *name,
1143 : u16 default_addr)
1144 : {
1145 0 : struct device_node *np = client->dev.of_node;
1146 0 : u32 addr = default_addr;
1147 : int i;
1148 :
1149 : if (np) {
1150 : i = of_property_match_string(np, "reg-names", name);
1151 : if (i >= 0)
1152 : of_property_read_u32_index(np, "reg", i, &addr);
1153 : }
1154 :
1155 : dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1156 0 : return i2c_new_dummy_device(client->adapter, addr);
1157 : }
1158 : EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1159 :
1160 : /* ------------------------------------------------------------------------- */
1161 :
1162 : /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1163 :
1164 0 : static void i2c_adapter_dev_release(struct device *dev)
1165 : {
1166 0 : struct i2c_adapter *adap = to_i2c_adapter(dev);
1167 0 : complete(&adap->dev_released);
1168 0 : }
1169 :
1170 0 : unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1171 : {
1172 0 : unsigned int depth = 0;
1173 :
1174 0 : while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1175 : depth++;
1176 :
1177 0 : WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1178 : "adapter depth exceeds lockdep subclass limit\n");
1179 :
1180 0 : return depth;
1181 : }
1182 : EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1183 :
1184 : /*
1185 : * Let users instantiate I2C devices through sysfs. This can be used when
1186 : * platform initialization code doesn't contain the proper data for
1187 : * whatever reason. Also useful for drivers that do device detection and
1188 : * detection fails, either because the device uses an unexpected address,
1189 : * or this is a compatible device with different ID register values.
1190 : *
1191 : * Parameter checking may look overzealous, but we really don't want
1192 : * the user to provide incorrect parameters.
1193 : */
1194 : static ssize_t
1195 0 : new_device_store(struct device *dev, struct device_attribute *attr,
1196 : const char *buf, size_t count)
1197 : {
1198 0 : struct i2c_adapter *adap = to_i2c_adapter(dev);
1199 : struct i2c_board_info info;
1200 : struct i2c_client *client;
1201 : char *blank, end;
1202 : int res;
1203 :
1204 0 : memset(&info, 0, sizeof(struct i2c_board_info));
1205 :
1206 0 : blank = strchr(buf, ' ');
1207 0 : if (!blank) {
1208 0 : dev_err(dev, "%s: Missing parameters\n", "new_device");
1209 0 : return -EINVAL;
1210 : }
1211 0 : if (blank - buf > I2C_NAME_SIZE - 1) {
1212 0 : dev_err(dev, "%s: Invalid device name\n", "new_device");
1213 0 : return -EINVAL;
1214 : }
1215 0 : memcpy(info.type, buf, blank - buf);
1216 :
1217 : /* Parse remaining parameters, reject extra parameters */
1218 0 : res = sscanf(++blank, "%hi%c", &info.addr, &end);
1219 0 : if (res < 1) {
1220 0 : dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1221 0 : return -EINVAL;
1222 : }
1223 0 : if (res > 1 && end != '\n') {
1224 0 : dev_err(dev, "%s: Extra parameters\n", "new_device");
1225 0 : return -EINVAL;
1226 : }
1227 :
1228 0 : if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1229 0 : info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1230 0 : info.flags |= I2C_CLIENT_TEN;
1231 : }
1232 :
1233 0 : if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1234 0 : info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1235 0 : info.flags |= I2C_CLIENT_SLAVE;
1236 : }
1237 :
1238 0 : client = i2c_new_client_device(adap, &info);
1239 0 : if (IS_ERR(client))
1240 0 : return PTR_ERR(client);
1241 :
1242 : /* Keep track of the added device */
1243 0 : mutex_lock(&adap->userspace_clients_lock);
1244 0 : list_add_tail(&client->detected, &adap->userspace_clients);
1245 0 : mutex_unlock(&adap->userspace_clients_lock);
1246 0 : dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1247 : info.type, info.addr);
1248 :
1249 0 : return count;
1250 : }
1251 : static DEVICE_ATTR_WO(new_device);
1252 :
1253 : /*
1254 : * And of course let the users delete the devices they instantiated, if
1255 : * they got it wrong. This interface can only be used to delete devices
1256 : * instantiated by i2c_sysfs_new_device above. This guarantees that we
1257 : * don't delete devices to which some kernel code still has references.
1258 : *
1259 : * Parameter checking may look overzealous, but we really don't want
1260 : * the user to delete the wrong device.
1261 : */
1262 : static ssize_t
1263 0 : delete_device_store(struct device *dev, struct device_attribute *attr,
1264 : const char *buf, size_t count)
1265 : {
1266 0 : struct i2c_adapter *adap = to_i2c_adapter(dev);
1267 : struct i2c_client *client, *next;
1268 : unsigned short addr;
1269 : char end;
1270 : int res;
1271 :
1272 : /* Parse parameters, reject extra parameters */
1273 0 : res = sscanf(buf, "%hi%c", &addr, &end);
1274 0 : if (res < 1) {
1275 0 : dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1276 0 : return -EINVAL;
1277 : }
1278 0 : if (res > 1 && end != '\n') {
1279 0 : dev_err(dev, "%s: Extra parameters\n", "delete_device");
1280 0 : return -EINVAL;
1281 : }
1282 :
1283 : /* Make sure the device was added through sysfs */
1284 0 : res = -ENOENT;
1285 0 : mutex_lock_nested(&adap->userspace_clients_lock,
1286 : i2c_adapter_depth(adap));
1287 0 : list_for_each_entry_safe(client, next, &adap->userspace_clients,
1288 : detected) {
1289 0 : if (i2c_encode_flags_to_addr(client) == addr) {
1290 0 : dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1291 : "delete_device", client->name, client->addr);
1292 :
1293 0 : list_del(&client->detected);
1294 0 : i2c_unregister_device(client);
1295 0 : res = count;
1296 0 : break;
1297 : }
1298 : }
1299 0 : mutex_unlock(&adap->userspace_clients_lock);
1300 :
1301 0 : if (res < 0)
1302 0 : dev_err(dev, "%s: Can't find device in list\n",
1303 : "delete_device");
1304 0 : return res;
1305 : }
1306 : static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1307 : delete_device_store);
1308 :
1309 : static struct attribute *i2c_adapter_attrs[] = {
1310 : &dev_attr_name.attr,
1311 : &dev_attr_new_device.attr,
1312 : &dev_attr_delete_device.attr,
1313 : NULL
1314 : };
1315 : ATTRIBUTE_GROUPS(i2c_adapter);
1316 :
1317 : struct device_type i2c_adapter_type = {
1318 : .groups = i2c_adapter_groups,
1319 : .release = i2c_adapter_dev_release,
1320 : };
1321 : EXPORT_SYMBOL_GPL(i2c_adapter_type);
1322 :
1323 : /**
1324 : * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1325 : * @dev: device, probably from some driver model iterator
1326 : *
1327 : * When traversing the driver model tree, perhaps using driver model
1328 : * iterators like @device_for_each_child(), you can't assume very much
1329 : * about the nodes you find. Use this function to avoid oopses caused
1330 : * by wrongly treating some non-I2C device as an i2c_adapter.
1331 : */
1332 0 : struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1333 : {
1334 0 : return (dev->type == &i2c_adapter_type)
1335 0 : ? to_i2c_adapter(dev)
1336 0 : : NULL;
1337 : }
1338 : EXPORT_SYMBOL(i2c_verify_adapter);
1339 :
1340 : #ifdef CONFIG_I2C_COMPAT
1341 : static struct class_compat *i2c_adapter_compat_class;
1342 : #endif
1343 :
1344 0 : static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1345 : {
1346 : struct i2c_devinfo *devinfo;
1347 :
1348 0 : down_read(&__i2c_board_lock);
1349 0 : list_for_each_entry(devinfo, &__i2c_board_list, list) {
1350 0 : if (devinfo->busnum == adapter->nr &&
1351 0 : IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1352 0 : dev_err(&adapter->dev,
1353 : "Can't create device at 0x%02x\n",
1354 : devinfo->board_info.addr);
1355 : }
1356 0 : up_read(&__i2c_board_lock);
1357 0 : }
1358 :
1359 : static int i2c_do_add_adapter(struct i2c_driver *driver,
1360 : struct i2c_adapter *adap)
1361 : {
1362 : /* Detect supported devices on that bus, and instantiate them */
1363 0 : i2c_detect(adap, driver);
1364 :
1365 : return 0;
1366 : }
1367 :
1368 0 : static int __process_new_adapter(struct device_driver *d, void *data)
1369 : {
1370 0 : return i2c_do_add_adapter(to_i2c_driver(d), data);
1371 : }
1372 :
1373 : static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1374 : .lock_bus = i2c_adapter_lock_bus,
1375 : .trylock_bus = i2c_adapter_trylock_bus,
1376 : .unlock_bus = i2c_adapter_unlock_bus,
1377 : };
1378 :
1379 0 : static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1380 : {
1381 0 : struct irq_domain *domain = adap->host_notify_domain;
1382 : irq_hw_number_t hwirq;
1383 :
1384 0 : if (!domain)
1385 : return;
1386 :
1387 0 : for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1388 0 : irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1389 :
1390 0 : irq_domain_remove(domain);
1391 0 : adap->host_notify_domain = NULL;
1392 : }
1393 :
1394 0 : static int i2c_host_notify_irq_map(struct irq_domain *h,
1395 : unsigned int virq,
1396 : irq_hw_number_t hw_irq_num)
1397 : {
1398 0 : irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1399 :
1400 0 : return 0;
1401 : }
1402 :
1403 : static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1404 : .map = i2c_host_notify_irq_map,
1405 : };
1406 :
1407 0 : static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1408 : {
1409 : struct irq_domain *domain;
1410 :
1411 0 : if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1412 : return 0;
1413 :
1414 0 : domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1415 : I2C_ADDR_7BITS_COUNT,
1416 : &i2c_host_notify_irq_ops, adap);
1417 0 : if (!domain)
1418 : return -ENOMEM;
1419 :
1420 0 : adap->host_notify_domain = domain;
1421 :
1422 0 : return 0;
1423 : }
1424 :
1425 : /**
1426 : * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1427 : * I2C client.
1428 : * @adap: the adapter
1429 : * @addr: the I2C address of the notifying device
1430 : * Context: can't sleep
1431 : *
1432 : * Helper function to be called from an I2C bus driver's interrupt
1433 : * handler. It will schedule the Host Notify IRQ.
1434 : */
1435 0 : int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1436 : {
1437 : int irq;
1438 :
1439 0 : if (!adap)
1440 : return -EINVAL;
1441 :
1442 0 : irq = irq_find_mapping(adap->host_notify_domain, addr);
1443 0 : if (irq <= 0)
1444 : return -ENXIO;
1445 :
1446 0 : generic_handle_irq_safe(irq);
1447 :
1448 0 : return 0;
1449 : }
1450 : EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1451 :
1452 0 : static int i2c_register_adapter(struct i2c_adapter *adap)
1453 : {
1454 0 : int res = -EINVAL;
1455 :
1456 : /* Can't register until after driver model init */
1457 0 : if (WARN_ON(!is_registered)) {
1458 : res = -EAGAIN;
1459 : goto out_list;
1460 : }
1461 :
1462 : /* Sanity checks */
1463 0 : if (WARN(!adap->name[0], "i2c adapter has no name"))
1464 : goto out_list;
1465 :
1466 0 : if (!adap->algo) {
1467 0 : pr_err("adapter '%s': no algo supplied!\n", adap->name);
1468 0 : goto out_list;
1469 : }
1470 :
1471 0 : if (!adap->lock_ops)
1472 0 : adap->lock_ops = &i2c_adapter_lock_ops;
1473 :
1474 0 : adap->locked_flags = 0;
1475 0 : rt_mutex_init(&adap->bus_lock);
1476 0 : rt_mutex_init(&adap->mux_lock);
1477 0 : mutex_init(&adap->userspace_clients_lock);
1478 0 : INIT_LIST_HEAD(&adap->userspace_clients);
1479 :
1480 : /* Set default timeout to 1 second if not already set */
1481 0 : if (adap->timeout == 0)
1482 0 : adap->timeout = HZ;
1483 :
1484 : /* register soft irqs for Host Notify */
1485 0 : res = i2c_setup_host_notify_irq_domain(adap);
1486 0 : if (res) {
1487 0 : pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1488 : adap->name, res);
1489 0 : goto out_list;
1490 : }
1491 :
1492 0 : dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1493 0 : adap->dev.bus = &i2c_bus_type;
1494 0 : adap->dev.type = &i2c_adapter_type;
1495 0 : res = device_register(&adap->dev);
1496 0 : if (res) {
1497 0 : pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1498 0 : goto out_list;
1499 : }
1500 :
1501 0 : res = i2c_setup_smbus_alert(adap);
1502 : if (res)
1503 : goto out_reg;
1504 :
1505 0 : device_enable_async_suspend(&adap->dev);
1506 0 : pm_runtime_no_callbacks(&adap->dev);
1507 0 : pm_suspend_ignore_children(&adap->dev, true);
1508 0 : pm_runtime_enable(&adap->dev);
1509 :
1510 0 : res = i2c_init_recovery(adap);
1511 0 : if (res == -EPROBE_DEFER)
1512 : goto out_reg;
1513 :
1514 : dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1515 :
1516 : #ifdef CONFIG_I2C_COMPAT
1517 0 : res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1518 : adap->dev.parent);
1519 0 : if (res)
1520 0 : dev_warn(&adap->dev,
1521 : "Failed to create compatibility class link\n");
1522 : #endif
1523 :
1524 : /* create pre-declared device nodes */
1525 0 : of_i2c_register_devices(adap);
1526 0 : i2c_acpi_install_space_handler(adap);
1527 0 : i2c_acpi_register_devices(adap);
1528 :
1529 0 : if (adap->nr < __i2c_first_dynamic_bus_num)
1530 0 : i2c_scan_static_board_info(adap);
1531 :
1532 : /* Notify drivers */
1533 0 : mutex_lock(&core_lock);
1534 0 : bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1535 0 : mutex_unlock(&core_lock);
1536 :
1537 0 : return 0;
1538 :
1539 : out_reg:
1540 0 : init_completion(&adap->dev_released);
1541 0 : device_unregister(&adap->dev);
1542 0 : wait_for_completion(&adap->dev_released);
1543 : out_list:
1544 0 : mutex_lock(&core_lock);
1545 0 : idr_remove(&i2c_adapter_idr, adap->nr);
1546 0 : mutex_unlock(&core_lock);
1547 0 : return res;
1548 : }
1549 :
1550 : /**
1551 : * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1552 : * @adap: the adapter to register (with adap->nr initialized)
1553 : * Context: can sleep
1554 : *
1555 : * See i2c_add_numbered_adapter() for details.
1556 : */
1557 0 : static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1558 : {
1559 : int id;
1560 :
1561 0 : mutex_lock(&core_lock);
1562 0 : id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1563 0 : mutex_unlock(&core_lock);
1564 0 : if (WARN(id < 0, "couldn't get idr"))
1565 0 : return id == -ENOSPC ? -EBUSY : id;
1566 :
1567 0 : return i2c_register_adapter(adap);
1568 : }
1569 :
1570 : /**
1571 : * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1572 : * @adapter: the adapter to add
1573 : * Context: can sleep
1574 : *
1575 : * This routine is used to declare an I2C adapter when its bus number
1576 : * doesn't matter or when its bus number is specified by an dt alias.
1577 : * Examples of bases when the bus number doesn't matter: I2C adapters
1578 : * dynamically added by USB links or PCI plugin cards.
1579 : *
1580 : * When this returns zero, a new bus number was allocated and stored
1581 : * in adap->nr, and the specified adapter became available for clients.
1582 : * Otherwise, a negative errno value is returned.
1583 : */
1584 0 : int i2c_add_adapter(struct i2c_adapter *adapter)
1585 : {
1586 0 : struct device *dev = &adapter->dev;
1587 : int id;
1588 :
1589 : if (dev->of_node) {
1590 : id = of_alias_get_id(dev->of_node, "i2c");
1591 : if (id >= 0) {
1592 : adapter->nr = id;
1593 : return __i2c_add_numbered_adapter(adapter);
1594 : }
1595 : }
1596 :
1597 0 : mutex_lock(&core_lock);
1598 0 : id = idr_alloc(&i2c_adapter_idr, adapter,
1599 : __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1600 0 : mutex_unlock(&core_lock);
1601 0 : if (WARN(id < 0, "couldn't get idr"))
1602 : return id;
1603 :
1604 0 : adapter->nr = id;
1605 :
1606 0 : return i2c_register_adapter(adapter);
1607 : }
1608 : EXPORT_SYMBOL(i2c_add_adapter);
1609 :
1610 : /**
1611 : * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1612 : * @adap: the adapter to register (with adap->nr initialized)
1613 : * Context: can sleep
1614 : *
1615 : * This routine is used to declare an I2C adapter when its bus number
1616 : * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1617 : * or otherwise built in to the system's mainboard, and where i2c_board_info
1618 : * is used to properly configure I2C devices.
1619 : *
1620 : * If the requested bus number is set to -1, then this function will behave
1621 : * identically to i2c_add_adapter, and will dynamically assign a bus number.
1622 : *
1623 : * If no devices have pre-been declared for this bus, then be sure to
1624 : * register the adapter before any dynamically allocated ones. Otherwise
1625 : * the required bus ID may not be available.
1626 : *
1627 : * When this returns zero, the specified adapter became available for
1628 : * clients using the bus number provided in adap->nr. Also, the table
1629 : * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1630 : * and the appropriate driver model device nodes are created. Otherwise, a
1631 : * negative errno value is returned.
1632 : */
1633 0 : int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1634 : {
1635 0 : if (adap->nr == -1) /* -1 means dynamically assign bus id */
1636 0 : return i2c_add_adapter(adap);
1637 :
1638 0 : return __i2c_add_numbered_adapter(adap);
1639 : }
1640 : EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1641 :
1642 0 : static void i2c_do_del_adapter(struct i2c_driver *driver,
1643 : struct i2c_adapter *adapter)
1644 : {
1645 : struct i2c_client *client, *_n;
1646 :
1647 : /* Remove the devices we created ourselves as the result of hardware
1648 : * probing (using a driver's detect method) */
1649 0 : list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1650 0 : if (client->adapter == adapter) {
1651 : dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1652 : client->name, client->addr);
1653 0 : list_del(&client->detected);
1654 0 : i2c_unregister_device(client);
1655 : }
1656 : }
1657 0 : }
1658 :
1659 0 : static int __unregister_client(struct device *dev, void *dummy)
1660 : {
1661 0 : struct i2c_client *client = i2c_verify_client(dev);
1662 0 : if (client && strcmp(client->name, "dummy"))
1663 0 : i2c_unregister_device(client);
1664 0 : return 0;
1665 : }
1666 :
1667 0 : static int __unregister_dummy(struct device *dev, void *dummy)
1668 : {
1669 0 : struct i2c_client *client = i2c_verify_client(dev);
1670 0 : i2c_unregister_device(client);
1671 0 : return 0;
1672 : }
1673 :
1674 0 : static int __process_removed_adapter(struct device_driver *d, void *data)
1675 : {
1676 0 : i2c_do_del_adapter(to_i2c_driver(d), data);
1677 0 : return 0;
1678 : }
1679 :
1680 : /**
1681 : * i2c_del_adapter - unregister I2C adapter
1682 : * @adap: the adapter being unregistered
1683 : * Context: can sleep
1684 : *
1685 : * This unregisters an I2C adapter which was previously registered
1686 : * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1687 : */
1688 0 : void i2c_del_adapter(struct i2c_adapter *adap)
1689 : {
1690 : struct i2c_adapter *found;
1691 : struct i2c_client *client, *next;
1692 :
1693 : /* First make sure that this adapter was ever added */
1694 0 : mutex_lock(&core_lock);
1695 0 : found = idr_find(&i2c_adapter_idr, adap->nr);
1696 0 : mutex_unlock(&core_lock);
1697 0 : if (found != adap) {
1698 : pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1699 : return;
1700 : }
1701 :
1702 0 : i2c_acpi_remove_space_handler(adap);
1703 : /* Tell drivers about this removal */
1704 0 : mutex_lock(&core_lock);
1705 0 : bus_for_each_drv(&i2c_bus_type, NULL, adap,
1706 : __process_removed_adapter);
1707 0 : mutex_unlock(&core_lock);
1708 :
1709 : /* Remove devices instantiated from sysfs */
1710 0 : mutex_lock_nested(&adap->userspace_clients_lock,
1711 : i2c_adapter_depth(adap));
1712 0 : list_for_each_entry_safe(client, next, &adap->userspace_clients,
1713 : detected) {
1714 : dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1715 : client->addr);
1716 0 : list_del(&client->detected);
1717 0 : i2c_unregister_device(client);
1718 : }
1719 0 : mutex_unlock(&adap->userspace_clients_lock);
1720 :
1721 : /* Detach any active clients. This can't fail, thus we do not
1722 : * check the returned value. This is a two-pass process, because
1723 : * we can't remove the dummy devices during the first pass: they
1724 : * could have been instantiated by real devices wishing to clean
1725 : * them up properly, so we give them a chance to do that first. */
1726 0 : device_for_each_child(&adap->dev, NULL, __unregister_client);
1727 0 : device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1728 :
1729 : #ifdef CONFIG_I2C_COMPAT
1730 0 : class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1731 : adap->dev.parent);
1732 : #endif
1733 :
1734 : /* device name is gone after device_unregister */
1735 : dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1736 :
1737 0 : pm_runtime_disable(&adap->dev);
1738 :
1739 0 : i2c_host_notify_irq_teardown(adap);
1740 :
1741 : /* wait until all references to the device are gone
1742 : *
1743 : * FIXME: This is old code and should ideally be replaced by an
1744 : * alternative which results in decoupling the lifetime of the struct
1745 : * device from the i2c_adapter, like spi or netdev do. Any solution
1746 : * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1747 : */
1748 0 : init_completion(&adap->dev_released);
1749 0 : device_unregister(&adap->dev);
1750 0 : wait_for_completion(&adap->dev_released);
1751 :
1752 : /* free bus id */
1753 0 : mutex_lock(&core_lock);
1754 0 : idr_remove(&i2c_adapter_idr, adap->nr);
1755 0 : mutex_unlock(&core_lock);
1756 :
1757 : /* Clear the device structure in case this adapter is ever going to be
1758 : added again */
1759 0 : memset(&adap->dev, 0, sizeof(adap->dev));
1760 : }
1761 : EXPORT_SYMBOL(i2c_del_adapter);
1762 :
1763 0 : static void devm_i2c_del_adapter(void *adapter)
1764 : {
1765 0 : i2c_del_adapter(adapter);
1766 0 : }
1767 :
1768 : /**
1769 : * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1770 : * @dev: managing device for adding this I2C adapter
1771 : * @adapter: the adapter to add
1772 : * Context: can sleep
1773 : *
1774 : * Add adapter with dynamic bus number, same with i2c_add_adapter()
1775 : * but the adapter will be auto deleted on driver detach.
1776 : */
1777 0 : int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1778 : {
1779 : int ret;
1780 :
1781 0 : ret = i2c_add_adapter(adapter);
1782 0 : if (ret)
1783 : return ret;
1784 :
1785 : return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1786 : }
1787 : EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1788 :
1789 0 : static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1790 : {
1791 0 : if (dev_fwnode(dev) == data)
1792 : return 1;
1793 :
1794 0 : if (dev->parent && dev_fwnode(dev->parent) == data)
1795 : return 1;
1796 :
1797 : return 0;
1798 : }
1799 :
1800 : /**
1801 : * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1802 : * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1803 : *
1804 : * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1805 : * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1806 : *
1807 : * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1808 : */
1809 0 : struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1810 : {
1811 : struct i2c_adapter *adapter;
1812 : struct device *dev;
1813 :
1814 0 : if (!fwnode)
1815 : return NULL;
1816 :
1817 0 : dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1818 : i2c_dev_or_parent_fwnode_match);
1819 0 : if (!dev)
1820 : return NULL;
1821 :
1822 0 : adapter = i2c_verify_adapter(dev);
1823 0 : if (!adapter)
1824 0 : put_device(dev);
1825 :
1826 : return adapter;
1827 : }
1828 : EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1829 :
1830 : /**
1831 : * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1832 : * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1833 : *
1834 : * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1835 : * and increment the adapter module's use count. If no adapter can be found,
1836 : * or @fwnode is NULL, this returns NULL.
1837 : *
1838 : * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1839 : * Note that this is different from i2c_find_adapter_by_node().
1840 : */
1841 0 : struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1842 : {
1843 : struct i2c_adapter *adapter;
1844 :
1845 0 : adapter = i2c_find_adapter_by_fwnode(fwnode);
1846 0 : if (!adapter)
1847 : return NULL;
1848 :
1849 0 : if (!try_module_get(adapter->owner)) {
1850 : put_device(&adapter->dev);
1851 : adapter = NULL;
1852 : }
1853 :
1854 0 : return adapter;
1855 : }
1856 : EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1857 :
1858 : static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1859 : u32 def_val, bool use_def)
1860 : {
1861 : int ret;
1862 :
1863 0 : ret = device_property_read_u32(dev, prop_name, cur_val_p);
1864 0 : if (ret && use_def)
1865 0 : *cur_val_p = def_val;
1866 :
1867 : dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1868 : }
1869 :
1870 : /**
1871 : * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1872 : * @dev: The device to scan for I2C timing properties
1873 : * @t: the i2c_timings struct to be filled with values
1874 : * @use_defaults: bool to use sane defaults derived from the I2C specification
1875 : * when properties are not found, otherwise don't update
1876 : *
1877 : * Scan the device for the generic I2C properties describing timing parameters
1878 : * for the signal and fill the given struct with the results. If a property was
1879 : * not found and use_defaults was true, then maximum timings are assumed which
1880 : * are derived from the I2C specification. If use_defaults is not used, the
1881 : * results will be as before, so drivers can apply their own defaults before
1882 : * calling this helper. The latter is mainly intended for avoiding regressions
1883 : * of existing drivers which want to switch to this function. New drivers
1884 : * almost always should use the defaults.
1885 : */
1886 0 : void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1887 : {
1888 0 : bool u = use_defaults;
1889 : u32 d;
1890 :
1891 0 : i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1892 : I2C_MAX_STANDARD_MODE_FREQ, u);
1893 :
1894 0 : d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1895 : t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1896 0 : i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1897 :
1898 0 : d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1899 0 : i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1900 :
1901 0 : i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1902 : &t->scl_int_delay_ns, 0, u);
1903 0 : i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1904 : t->scl_fall_ns, u);
1905 0 : i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1906 0 : i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1907 : &t->digital_filter_width_ns, 0, u);
1908 0 : i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1909 : &t->analog_filter_cutoff_freq_hz, 0, u);
1910 0 : }
1911 : EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1912 :
1913 : /* ------------------------------------------------------------------------- */
1914 :
1915 1 : int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1916 : {
1917 : int res;
1918 :
1919 1 : mutex_lock(&core_lock);
1920 1 : res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1921 1 : mutex_unlock(&core_lock);
1922 :
1923 1 : return res;
1924 : }
1925 : EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1926 :
1927 0 : static int __process_new_driver(struct device *dev, void *data)
1928 : {
1929 0 : if (dev->type != &i2c_adapter_type)
1930 : return 0;
1931 0 : return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1932 : }
1933 :
1934 : /*
1935 : * An i2c_driver is used with one or more i2c_client (device) nodes to access
1936 : * i2c slave chips, on a bus instance associated with some i2c_adapter.
1937 : */
1938 :
1939 1 : int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1940 : {
1941 : int res;
1942 :
1943 : /* Can't register until after driver model init */
1944 1 : if (WARN_ON(!is_registered))
1945 : return -EAGAIN;
1946 :
1947 : /* add the driver to the list of i2c drivers in the driver core */
1948 1 : driver->driver.owner = owner;
1949 1 : driver->driver.bus = &i2c_bus_type;
1950 2 : INIT_LIST_HEAD(&driver->clients);
1951 :
1952 : /* When registration returns, the driver core
1953 : * will have called probe() for all matching-but-unbound devices.
1954 : */
1955 1 : res = driver_register(&driver->driver);
1956 1 : if (res)
1957 : return res;
1958 :
1959 : pr_debug("driver [%s] registered\n", driver->driver.name);
1960 :
1961 : /* Walk the adapters that are already present */
1962 1 : i2c_for_each_dev(driver, __process_new_driver);
1963 :
1964 1 : return 0;
1965 : }
1966 : EXPORT_SYMBOL(i2c_register_driver);
1967 :
1968 0 : static int __process_removed_driver(struct device *dev, void *data)
1969 : {
1970 0 : if (dev->type == &i2c_adapter_type)
1971 0 : i2c_do_del_adapter(data, to_i2c_adapter(dev));
1972 0 : return 0;
1973 : }
1974 :
1975 : /**
1976 : * i2c_del_driver - unregister I2C driver
1977 : * @driver: the driver being unregistered
1978 : * Context: can sleep
1979 : */
1980 0 : void i2c_del_driver(struct i2c_driver *driver)
1981 : {
1982 0 : i2c_for_each_dev(driver, __process_removed_driver);
1983 :
1984 0 : driver_unregister(&driver->driver);
1985 : pr_debug("driver [%s] unregistered\n", driver->driver.name);
1986 0 : }
1987 : EXPORT_SYMBOL(i2c_del_driver);
1988 :
1989 : /* ------------------------------------------------------------------------- */
1990 :
1991 : struct i2c_cmd_arg {
1992 : unsigned cmd;
1993 : void *arg;
1994 : };
1995 :
1996 0 : static int i2c_cmd(struct device *dev, void *_arg)
1997 : {
1998 0 : struct i2c_client *client = i2c_verify_client(dev);
1999 0 : struct i2c_cmd_arg *arg = _arg;
2000 : struct i2c_driver *driver;
2001 :
2002 0 : if (!client || !client->dev.driver)
2003 : return 0;
2004 :
2005 0 : driver = to_i2c_driver(client->dev.driver);
2006 0 : if (driver->command)
2007 0 : driver->command(client, arg->cmd, arg->arg);
2008 : return 0;
2009 : }
2010 :
2011 0 : void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2012 : {
2013 : struct i2c_cmd_arg cmd_arg;
2014 :
2015 0 : cmd_arg.cmd = cmd;
2016 0 : cmd_arg.arg = arg;
2017 0 : device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2018 0 : }
2019 : EXPORT_SYMBOL(i2c_clients_command);
2020 :
2021 1 : static int __init i2c_init(void)
2022 : {
2023 : int retval;
2024 :
2025 1 : retval = of_alias_get_highest_id("i2c");
2026 :
2027 1 : down_write(&__i2c_board_lock);
2028 1 : if (retval >= __i2c_first_dynamic_bus_num)
2029 0 : __i2c_first_dynamic_bus_num = retval + 1;
2030 1 : up_write(&__i2c_board_lock);
2031 :
2032 1 : retval = bus_register(&i2c_bus_type);
2033 1 : if (retval)
2034 : return retval;
2035 :
2036 1 : is_registered = true;
2037 :
2038 : #ifdef CONFIG_I2C_COMPAT
2039 1 : i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2040 1 : if (!i2c_adapter_compat_class) {
2041 : retval = -ENOMEM;
2042 : goto bus_err;
2043 : }
2044 : #endif
2045 1 : retval = i2c_add_driver(&dummy_driver);
2046 1 : if (retval)
2047 : goto class_err;
2048 :
2049 : if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2050 : WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2051 : if (IS_ENABLED(CONFIG_ACPI))
2052 : WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2053 :
2054 : return 0;
2055 :
2056 : class_err:
2057 : #ifdef CONFIG_I2C_COMPAT
2058 0 : class_compat_unregister(i2c_adapter_compat_class);
2059 : bus_err:
2060 : #endif
2061 0 : is_registered = false;
2062 0 : bus_unregister(&i2c_bus_type);
2063 0 : return retval;
2064 : }
2065 :
2066 0 : static void __exit i2c_exit(void)
2067 : {
2068 : if (IS_ENABLED(CONFIG_ACPI))
2069 : WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2070 : if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2071 : WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2072 0 : i2c_del_driver(&dummy_driver);
2073 : #ifdef CONFIG_I2C_COMPAT
2074 0 : class_compat_unregister(i2c_adapter_compat_class);
2075 : #endif
2076 0 : bus_unregister(&i2c_bus_type);
2077 : tracepoint_synchronize_unregister();
2078 0 : }
2079 :
2080 : /* We must initialize early, because some subsystems register i2c drivers
2081 : * in subsys_initcall() code, but are linked (and initialized) before i2c.
2082 : */
2083 : postcore_initcall(i2c_init);
2084 : module_exit(i2c_exit);
2085 :
2086 : /* ----------------------------------------------------
2087 : * the functional interface to the i2c busses.
2088 : * ----------------------------------------------------
2089 : */
2090 :
2091 : /* Check if val is exceeding the quirk IFF quirk is non 0 */
2092 : #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2093 :
2094 0 : static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2095 : {
2096 0 : dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2097 : err_msg, msg->addr, msg->len,
2098 : msg->flags & I2C_M_RD ? "read" : "write");
2099 0 : return -EOPNOTSUPP;
2100 : }
2101 :
2102 0 : static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2103 : {
2104 0 : const struct i2c_adapter_quirks *q = adap->quirks;
2105 0 : int max_num = q->max_num_msgs, i;
2106 0 : bool do_len_check = true;
2107 :
2108 0 : if (q->flags & I2C_AQ_COMB) {
2109 0 : max_num = 2;
2110 :
2111 : /* special checks for combined messages */
2112 0 : if (num == 2) {
2113 0 : if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2114 0 : return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2115 :
2116 0 : if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2117 0 : return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2118 :
2119 0 : if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2120 0 : return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2121 :
2122 0 : if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2123 0 : return i2c_quirk_error(adap, &msgs[0], "msg too long");
2124 :
2125 0 : if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2126 0 : return i2c_quirk_error(adap, &msgs[1], "msg too long");
2127 :
2128 : do_len_check = false;
2129 : }
2130 : }
2131 :
2132 0 : if (i2c_quirk_exceeded(num, max_num))
2133 0 : return i2c_quirk_error(adap, &msgs[0], "too many messages");
2134 :
2135 0 : for (i = 0; i < num; i++) {
2136 0 : u16 len = msgs[i].len;
2137 :
2138 0 : if (msgs[i].flags & I2C_M_RD) {
2139 0 : if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2140 0 : return i2c_quirk_error(adap, &msgs[i], "msg too long");
2141 :
2142 0 : if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2143 0 : return i2c_quirk_error(adap, &msgs[i], "no zero length");
2144 : } else {
2145 0 : if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2146 0 : return i2c_quirk_error(adap, &msgs[i], "msg too long");
2147 :
2148 0 : if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2149 0 : return i2c_quirk_error(adap, &msgs[i], "no zero length");
2150 : }
2151 : }
2152 :
2153 : return 0;
2154 : }
2155 :
2156 : /**
2157 : * __i2c_transfer - unlocked flavor of i2c_transfer
2158 : * @adap: Handle to I2C bus
2159 : * @msgs: One or more messages to execute before STOP is issued to
2160 : * terminate the operation; each message begins with a START.
2161 : * @num: Number of messages to be executed.
2162 : *
2163 : * Returns negative errno, else the number of messages executed.
2164 : *
2165 : * Adapter lock must be held when calling this function. No debug logging
2166 : * takes place. adap->algo->master_xfer existence isn't checked.
2167 : */
2168 0 : int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2169 : {
2170 : unsigned long orig_jiffies;
2171 : int ret, try;
2172 :
2173 0 : if (WARN_ON(!msgs || num < 1))
2174 : return -EINVAL;
2175 :
2176 0 : ret = __i2c_check_suspended(adap);
2177 0 : if (ret)
2178 : return ret;
2179 :
2180 0 : if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2181 : return -EOPNOTSUPP;
2182 :
2183 : /*
2184 : * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2185 : * enabled. This is an efficient way of keeping the for-loop from
2186 : * being executed when not needed.
2187 : */
2188 0 : if (static_branch_unlikely(&i2c_trace_msg_key)) {
2189 : int i;
2190 : for (i = 0; i < num; i++)
2191 : if (msgs[i].flags & I2C_M_RD)
2192 : trace_i2c_read(adap, &msgs[i], i);
2193 : else
2194 : trace_i2c_write(adap, &msgs[i], i);
2195 : }
2196 :
2197 : /* Retry automatically on arbitration loss */
2198 0 : orig_jiffies = jiffies;
2199 0 : for (ret = 0, try = 0; try <= adap->retries; try++) {
2200 0 : if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2201 0 : ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2202 : else
2203 0 : ret = adap->algo->master_xfer(adap, msgs, num);
2204 :
2205 0 : if (ret != -EAGAIN)
2206 : break;
2207 0 : if (time_after(jiffies, orig_jiffies + adap->timeout))
2208 : break;
2209 : }
2210 :
2211 0 : if (static_branch_unlikely(&i2c_trace_msg_key)) {
2212 : int i;
2213 : for (i = 0; i < ret; i++)
2214 : if (msgs[i].flags & I2C_M_RD)
2215 : trace_i2c_reply(adap, &msgs[i], i);
2216 : trace_i2c_result(adap, num, ret);
2217 : }
2218 :
2219 : return ret;
2220 : }
2221 : EXPORT_SYMBOL(__i2c_transfer);
2222 :
2223 : /**
2224 : * i2c_transfer - execute a single or combined I2C message
2225 : * @adap: Handle to I2C bus
2226 : * @msgs: One or more messages to execute before STOP is issued to
2227 : * terminate the operation; each message begins with a START.
2228 : * @num: Number of messages to be executed.
2229 : *
2230 : * Returns negative errno, else the number of messages executed.
2231 : *
2232 : * Note that there is no requirement that each message be sent to
2233 : * the same slave address, although that is the most common model.
2234 : */
2235 0 : int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2236 : {
2237 : int ret;
2238 :
2239 0 : if (!adap->algo->master_xfer) {
2240 : dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2241 : return -EOPNOTSUPP;
2242 : }
2243 :
2244 : /* REVISIT the fault reporting model here is weak:
2245 : *
2246 : * - When we get an error after receiving N bytes from a slave,
2247 : * there is no way to report "N".
2248 : *
2249 : * - When we get a NAK after transmitting N bytes to a slave,
2250 : * there is no way to report "N" ... or to let the master
2251 : * continue executing the rest of this combined message, if
2252 : * that's the appropriate response.
2253 : *
2254 : * - When for example "num" is two and we successfully complete
2255 : * the first message but get an error part way through the
2256 : * second, it's unclear whether that should be reported as
2257 : * one (discarding status on the second message) or errno
2258 : * (discarding status on the first one).
2259 : */
2260 0 : ret = __i2c_lock_bus_helper(adap);
2261 0 : if (ret)
2262 : return ret;
2263 :
2264 0 : ret = __i2c_transfer(adap, msgs, num);
2265 0 : i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2266 :
2267 0 : return ret;
2268 : }
2269 : EXPORT_SYMBOL(i2c_transfer);
2270 :
2271 : /**
2272 : * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2273 : * to/from a buffer
2274 : * @client: Handle to slave device
2275 : * @buf: Where the data is stored
2276 : * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2277 : * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2278 : *
2279 : * Returns negative errno, or else the number of bytes transferred.
2280 : */
2281 0 : int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2282 : int count, u16 flags)
2283 : {
2284 : int ret;
2285 0 : struct i2c_msg msg = {
2286 0 : .addr = client->addr,
2287 0 : .flags = flags | (client->flags & I2C_M_TEN),
2288 : .len = count,
2289 : .buf = buf,
2290 : };
2291 :
2292 0 : ret = i2c_transfer(client->adapter, &msg, 1);
2293 :
2294 : /*
2295 : * If everything went ok (i.e. 1 msg transferred), return #bytes
2296 : * transferred, else error code.
2297 : */
2298 0 : return (ret == 1) ? count : ret;
2299 : }
2300 : EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2301 :
2302 : /**
2303 : * i2c_get_device_id - get manufacturer, part id and die revision of a device
2304 : * @client: The device to query
2305 : * @id: The queried information
2306 : *
2307 : * Returns negative errno on error, zero on success.
2308 : */
2309 0 : int i2c_get_device_id(const struct i2c_client *client,
2310 : struct i2c_device_identity *id)
2311 : {
2312 0 : struct i2c_adapter *adap = client->adapter;
2313 : union i2c_smbus_data raw_id;
2314 : int ret;
2315 :
2316 0 : if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2317 : return -EOPNOTSUPP;
2318 :
2319 0 : raw_id.block[0] = 3;
2320 0 : ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2321 0 : I2C_SMBUS_READ, client->addr << 1,
2322 : I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2323 0 : if (ret)
2324 : return ret;
2325 :
2326 0 : id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2327 0 : id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2328 0 : id->die_revision = raw_id.block[3] & 0x7;
2329 0 : return 0;
2330 : }
2331 : EXPORT_SYMBOL_GPL(i2c_get_device_id);
2332 :
2333 : /**
2334 : * i2c_client_get_device_id - get the driver match table entry of a device
2335 : * @client: the device to query. The device must be bound to a driver
2336 : *
2337 : * Returns a pointer to the matching entry if found, NULL otherwise.
2338 : */
2339 0 : const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2340 : {
2341 0 : const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2342 :
2343 0 : return i2c_match_id(drv->id_table, client);
2344 : }
2345 : EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2346 :
2347 : /* ----------------------------------------------------
2348 : * the i2c address scanning function
2349 : * Will not work for 10-bit addresses!
2350 : * ----------------------------------------------------
2351 : */
2352 :
2353 : /*
2354 : * Legacy default probe function, mostly relevant for SMBus. The default
2355 : * probe method is a quick write, but it is known to corrupt the 24RF08
2356 : * EEPROMs due to a state machine bug, and could also irreversibly
2357 : * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2358 : * we use a short byte read instead. Also, some bus drivers don't implement
2359 : * quick write, so we fallback to a byte read in that case too.
2360 : * On x86, there is another special case for FSC hardware monitoring chips,
2361 : * which want regular byte reads (address 0x73.) Fortunately, these are the
2362 : * only known chips using this I2C address on PC hardware.
2363 : * Returns 1 if probe succeeded, 0 if not.
2364 : */
2365 0 : static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2366 : {
2367 : int err;
2368 : union i2c_smbus_data dummy;
2369 :
2370 : #ifdef CONFIG_X86
2371 : if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2372 : && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2373 : err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2374 : I2C_SMBUS_BYTE_DATA, &dummy);
2375 : else
2376 : #endif
2377 0 : if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2378 0 : && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2379 0 : err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2380 : I2C_SMBUS_QUICK, NULL);
2381 0 : else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2382 0 : err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2383 : I2C_SMBUS_BYTE, &dummy);
2384 : else {
2385 0 : dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2386 : addr);
2387 0 : err = -EOPNOTSUPP;
2388 : }
2389 :
2390 0 : return err >= 0;
2391 : }
2392 :
2393 0 : static int i2c_detect_address(struct i2c_client *temp_client,
2394 : struct i2c_driver *driver)
2395 : {
2396 : struct i2c_board_info info;
2397 0 : struct i2c_adapter *adapter = temp_client->adapter;
2398 0 : int addr = temp_client->addr;
2399 : int err;
2400 :
2401 : /* Make sure the address is valid */
2402 0 : err = i2c_check_7bit_addr_validity_strict(addr);
2403 0 : if (err) {
2404 0 : dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2405 : addr);
2406 0 : return err;
2407 : }
2408 :
2409 : /* Skip if already in use (7 bit, no need to encode flags) */
2410 0 : if (i2c_check_addr_busy(adapter, addr))
2411 : return 0;
2412 :
2413 : /* Make sure there is something at this address */
2414 0 : if (!i2c_default_probe(adapter, addr))
2415 : return 0;
2416 :
2417 : /* Finally call the custom detection function */
2418 0 : memset(&info, 0, sizeof(struct i2c_board_info));
2419 0 : info.addr = addr;
2420 0 : err = driver->detect(temp_client, &info);
2421 0 : if (err) {
2422 : /* -ENODEV is returned if the detection fails. We catch it
2423 : here as this isn't an error. */
2424 0 : return err == -ENODEV ? 0 : err;
2425 : }
2426 :
2427 : /* Consistency check */
2428 0 : if (info.type[0] == '\0') {
2429 0 : dev_err(&adapter->dev,
2430 : "%s detection function provided no name for 0x%x\n",
2431 : driver->driver.name, addr);
2432 : } else {
2433 : struct i2c_client *client;
2434 :
2435 : /* Detection succeeded, instantiate the device */
2436 0 : if (adapter->class & I2C_CLASS_DEPRECATED)
2437 0 : dev_warn(&adapter->dev,
2438 : "This adapter will soon drop class based instantiation of devices. "
2439 : "Please make sure client 0x%02x gets instantiated by other means. "
2440 : "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2441 : info.addr);
2442 :
2443 : dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2444 : info.type, info.addr);
2445 0 : client = i2c_new_client_device(adapter, &info);
2446 0 : if (!IS_ERR(client))
2447 0 : list_add_tail(&client->detected, &driver->clients);
2448 : else
2449 0 : dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2450 : info.type, info.addr);
2451 : }
2452 : return 0;
2453 : }
2454 :
2455 0 : static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2456 : {
2457 : const unsigned short *address_list;
2458 : struct i2c_client *temp_client;
2459 0 : int i, err = 0;
2460 :
2461 0 : address_list = driver->address_list;
2462 0 : if (!driver->detect || !address_list)
2463 : return 0;
2464 :
2465 : /* Warn that the adapter lost class based instantiation */
2466 0 : if (adapter->class == I2C_CLASS_DEPRECATED) {
2467 : dev_dbg(&adapter->dev,
2468 : "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2469 : "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2470 : driver->driver.name);
2471 : return 0;
2472 : }
2473 :
2474 : /* Stop here if the classes do not match */
2475 0 : if (!(adapter->class & driver->class))
2476 : return 0;
2477 :
2478 : /* Set up a temporary client to help detect callback */
2479 0 : temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2480 0 : if (!temp_client)
2481 : return -ENOMEM;
2482 0 : temp_client->adapter = adapter;
2483 :
2484 0 : for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2485 : dev_dbg(&adapter->dev,
2486 : "found normal entry for adapter %d, addr 0x%02x\n",
2487 : i2c_adapter_id(adapter), address_list[i]);
2488 0 : temp_client->addr = address_list[i];
2489 0 : err = i2c_detect_address(temp_client, driver);
2490 0 : if (unlikely(err))
2491 : break;
2492 : }
2493 :
2494 0 : kfree(temp_client);
2495 0 : return err;
2496 : }
2497 :
2498 0 : int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2499 : {
2500 0 : return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2501 0 : I2C_SMBUS_QUICK, NULL) >= 0;
2502 : }
2503 : EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2504 :
2505 : struct i2c_client *
2506 0 : i2c_new_scanned_device(struct i2c_adapter *adap,
2507 : struct i2c_board_info *info,
2508 : unsigned short const *addr_list,
2509 : int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2510 : {
2511 : int i;
2512 :
2513 0 : if (!probe)
2514 0 : probe = i2c_default_probe;
2515 :
2516 0 : for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2517 : /* Check address validity */
2518 0 : if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2519 0 : dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2520 : addr_list[i]);
2521 0 : continue;
2522 : }
2523 :
2524 : /* Check address availability (7 bit, no need to encode flags) */
2525 0 : if (i2c_check_addr_busy(adap, addr_list[i])) {
2526 : dev_dbg(&adap->dev,
2527 : "Address 0x%02x already in use, not probing\n",
2528 : addr_list[i]);
2529 0 : continue;
2530 : }
2531 :
2532 : /* Test address responsiveness */
2533 0 : if (probe(adap, addr_list[i]))
2534 : break;
2535 : }
2536 :
2537 0 : if (addr_list[i] == I2C_CLIENT_END) {
2538 : dev_dbg(&adap->dev, "Probing failed, no device found\n");
2539 : return ERR_PTR(-ENODEV);
2540 : }
2541 :
2542 0 : info->addr = addr_list[i];
2543 0 : return i2c_new_client_device(adap, info);
2544 : }
2545 : EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2546 :
2547 0 : struct i2c_adapter *i2c_get_adapter(int nr)
2548 : {
2549 : struct i2c_adapter *adapter;
2550 :
2551 0 : mutex_lock(&core_lock);
2552 0 : adapter = idr_find(&i2c_adapter_idr, nr);
2553 0 : if (!adapter)
2554 : goto exit;
2555 :
2556 0 : if (try_module_get(adapter->owner))
2557 0 : get_device(&adapter->dev);
2558 : else
2559 : adapter = NULL;
2560 :
2561 : exit:
2562 0 : mutex_unlock(&core_lock);
2563 0 : return adapter;
2564 : }
2565 : EXPORT_SYMBOL(i2c_get_adapter);
2566 :
2567 0 : void i2c_put_adapter(struct i2c_adapter *adap)
2568 : {
2569 0 : if (!adap)
2570 : return;
2571 :
2572 0 : module_put(adap->owner);
2573 : /* Should be last, otherwise we risk use-after-free with 'adap' */
2574 0 : put_device(&adap->dev);
2575 : }
2576 : EXPORT_SYMBOL(i2c_put_adapter);
2577 :
2578 : /**
2579 : * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2580 : * @msg: the message to be checked
2581 : * @threshold: the minimum number of bytes for which using DMA makes sense.
2582 : * Should at least be 1.
2583 : *
2584 : * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2585 : * Or a valid pointer to be used with DMA. After use, release it by
2586 : * calling i2c_put_dma_safe_msg_buf().
2587 : *
2588 : * This function must only be called from process context!
2589 : */
2590 0 : u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2591 : {
2592 : /* also skip 0-length msgs for bogus thresholds of 0 */
2593 : if (!threshold)
2594 : pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2595 : msg->addr);
2596 0 : if (msg->len < threshold || msg->len == 0)
2597 : return NULL;
2598 :
2599 0 : if (msg->flags & I2C_M_DMA_SAFE)
2600 0 : return msg->buf;
2601 :
2602 : pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2603 : msg->addr, msg->len);
2604 :
2605 0 : if (msg->flags & I2C_M_RD)
2606 0 : return kzalloc(msg->len, GFP_KERNEL);
2607 : else
2608 0 : return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2609 : }
2610 : EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2611 :
2612 : /**
2613 : * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2614 : * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2615 : * @msg: the message which the buffer corresponds to
2616 : * @xferred: bool saying if the message was transferred
2617 : */
2618 0 : void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2619 : {
2620 0 : if (!buf || buf == msg->buf)
2621 : return;
2622 :
2623 0 : if (xferred && msg->flags & I2C_M_RD)
2624 0 : memcpy(msg->buf, buf, msg->len);
2625 :
2626 0 : kfree(buf);
2627 : }
2628 : EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2629 :
2630 : MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2631 : MODULE_DESCRIPTION("I2C-Bus main module");
2632 : MODULE_LICENSE("GPL");
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