Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/debugfs.h>
20#include <linux/delay.h>
21#include <linux/err.h>
22#include <linux/errno.h>
23#include <linux/gpio/consumer.h>
24#include <linux/i2c.h>
25#include <linux/i2c-smbus.h>
26#include <linux/idr.h>
27#include <linux/init.h>
28#include <linux/interrupt.h>
29#include <linux/irq.h>
30#include <linux/jump_label.h>
31#include <linux/kernel.h>
32#include <linux/module.h>
33#include <linux/mutex.h>
34#include <linux/of_device.h>
35#include <linux/of.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#include <linux/string_choices.h>
45
46#include "i2c-core.h"
47
48#define CREATE_TRACE_POINTS
49#include <trace/events/i2c.h>
50
51#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
52#define I2C_ADDR_OFFSET_SLAVE 0x1000
53
54#define I2C_ADDR_7BITS_MAX 0x77
55#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
56
57#define I2C_ADDR_DEVICE_ID 0x7c
58
59/*
60 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
61 * deletion of detected devices are serialized
62 */
63static DEFINE_MUTEX(core_lock);
64static DEFINE_IDR(i2c_adapter_idr);
65
66static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
67
68static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
69static bool is_registered;
70
71static struct dentry *i2c_debugfs_root;
72
73int i2c_transfer_trace_reg(void)
74{
75 static_branch_inc(&i2c_trace_msg_key);
76 return 0;
77}
78
79void i2c_transfer_trace_unreg(void)
80{
81 static_branch_dec(&i2c_trace_msg_key);
82}
83
84const char *i2c_freq_mode_string(u32 bus_freq_hz)
85{
86 switch (bus_freq_hz) {
87 case I2C_MAX_STANDARD_MODE_FREQ:
88 return "Standard Mode (100 kHz)";
89 case I2C_MAX_FAST_MODE_FREQ:
90 return "Fast Mode (400 kHz)";
91 case I2C_MAX_FAST_MODE_PLUS_FREQ:
92 return "Fast Mode Plus (1.0 MHz)";
93 case I2C_MAX_TURBO_MODE_FREQ:
94 return "Turbo Mode (1.4 MHz)";
95 case I2C_MAX_HIGH_SPEED_MODE_FREQ:
96 return "High Speed Mode (3.4 MHz)";
97 case I2C_MAX_ULTRA_FAST_MODE_FREQ:
98 return "Ultra Fast Mode (5.0 MHz)";
99 default:
100 return "Unknown Mode";
101 }
102}
103EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
104
105const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
106 const struct i2c_client *client)
107{
108 if (!(id && client))
109 return NULL;
110
111 while (id->name[0]) {
112 if (strcmp(client->name, id->name) == 0)
113 return id;
114 id++;
115 }
116 return NULL;
117}
118EXPORT_SYMBOL_GPL(i2c_match_id);
119
120const void *i2c_get_match_data(const struct i2c_client *client)
121{
122 struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
123 const struct i2c_device_id *match;
124 const void *data;
125
126 data = device_get_match_data(&client->dev);
127 if (!data) {
128 match = i2c_match_id(driver->id_table, client);
129 if (!match)
130 return NULL;
131
132 data = (const void *)match->driver_data;
133 }
134
135 return data;
136}
137EXPORT_SYMBOL(i2c_get_match_data);
138
139static int i2c_device_match(struct device *dev, const struct device_driver *drv)
140{
141 struct i2c_client *client = i2c_verify_client(dev);
142 const struct i2c_driver *driver;
143
144
145 /* Attempt an OF style match */
146 if (i2c_of_match_device(drv->of_match_table, client))
147 return 1;
148
149 /* Then ACPI style match */
150 if (acpi_driver_match_device(dev, drv))
151 return 1;
152
153 driver = to_i2c_driver(drv);
154
155 /* Finally an I2C match */
156 if (i2c_match_id(driver->id_table, client))
157 return 1;
158
159 return 0;
160}
161
162static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
163{
164 const struct i2c_client *client = to_i2c_client(dev);
165 int rc;
166
167 rc = of_device_uevent_modalias(dev, env);
168 if (rc != -ENODEV)
169 return rc;
170
171 rc = acpi_device_uevent_modalias(dev, env);
172 if (rc != -ENODEV)
173 return rc;
174
175 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
176}
177
178/* i2c bus recovery routines */
179static int get_scl_gpio_value(struct i2c_adapter *adap)
180{
181 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
182}
183
184static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
185{
186 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
187}
188
189static int get_sda_gpio_value(struct i2c_adapter *adap)
190{
191 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
192}
193
194static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
195{
196 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
197}
198
199static int i2c_generic_bus_free(struct i2c_adapter *adap)
200{
201 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
202 int ret = -EOPNOTSUPP;
203
204 if (bri->get_bus_free)
205 ret = bri->get_bus_free(adap);
206 else if (bri->get_sda)
207 ret = bri->get_sda(adap);
208
209 if (ret < 0)
210 return ret;
211
212 return ret ? 0 : -EBUSY;
213}
214
215/*
216 * We are generating clock pulses. ndelay() determines durating of clk pulses.
217 * We will generate clock with rate 100 KHz and so duration of both clock levels
218 * is: delay in ns = (10^6 / 100) / 2
219 */
220#define RECOVERY_NDELAY 5000
221#define RECOVERY_CLK_CNT 9
222
223int i2c_generic_scl_recovery(struct i2c_adapter *adap)
224{
225 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
226 int i = 0, scl = 1, ret = 0;
227
228 if (bri->prepare_recovery)
229 bri->prepare_recovery(adap);
230 if (bri->pinctrl)
231 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
232
233 /*
234 * If we can set SDA, we will always create a STOP to ensure additional
235 * pulses will do no harm. This is achieved by letting SDA follow SCL
236 * half a cycle later. Check the 'incomplete_write_byte' fault injector
237 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
238 * here for simplicity.
239 */
240 bri->set_scl(adap, scl);
241 ndelay(RECOVERY_NDELAY);
242 if (bri->set_sda)
243 bri->set_sda(adap, scl);
244 ndelay(RECOVERY_NDELAY / 2);
245
246 /*
247 * By this time SCL is high, as we need to give 9 falling-rising edges
248 */
249 while (i++ < RECOVERY_CLK_CNT * 2) {
250 if (scl) {
251 /* SCL shouldn't be low here */
252 if (!bri->get_scl(adap)) {
253 dev_err(&adap->dev,
254 "SCL is stuck low, exit recovery\n");
255 ret = -EBUSY;
256 break;
257 }
258 }
259
260 scl = !scl;
261 bri->set_scl(adap, scl);
262 /* Creating STOP again, see above */
263 if (scl) {
264 /* Honour minimum tsu:sto */
265 ndelay(RECOVERY_NDELAY);
266 } else {
267 /* Honour minimum tf and thd:dat */
268 ndelay(RECOVERY_NDELAY / 2);
269 }
270 if (bri->set_sda)
271 bri->set_sda(adap, scl);
272 ndelay(RECOVERY_NDELAY / 2);
273
274 if (scl) {
275 ret = i2c_generic_bus_free(adap);
276 if (ret == 0)
277 break;
278 }
279 }
280
281 /* If we can't check bus status, assume recovery worked */
282 if (ret == -EOPNOTSUPP)
283 ret = 0;
284
285 if (bri->unprepare_recovery)
286 bri->unprepare_recovery(adap);
287 if (bri->pinctrl)
288 pinctrl_select_state(bri->pinctrl, bri->pins_default);
289
290 return ret;
291}
292EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
293
294int i2c_recover_bus(struct i2c_adapter *adap)
295{
296 if (!adap->bus_recovery_info)
297 return -EBUSY;
298
299 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
300 return adap->bus_recovery_info->recover_bus(adap);
301}
302EXPORT_SYMBOL_GPL(i2c_recover_bus);
303
304static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
305{
306 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
307 struct device *dev = &adap->dev;
308 struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
309
310 bri->pinctrl = p;
311
312 /*
313 * we can't change states without pinctrl, so remove the states if
314 * populated
315 */
316 if (!p) {
317 bri->pins_default = NULL;
318 bri->pins_gpio = NULL;
319 return;
320 }
321
322 if (!bri->pins_default) {
323 bri->pins_default = pinctrl_lookup_state(p,
324 PINCTRL_STATE_DEFAULT);
325 if (IS_ERR(bri->pins_default)) {
326 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
327 bri->pins_default = NULL;
328 }
329 }
330 if (!bri->pins_gpio) {
331 bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
332 if (IS_ERR(bri->pins_gpio))
333 bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
334
335 if (IS_ERR(bri->pins_gpio)) {
336 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
337 bri->pins_gpio = NULL;
338 }
339 }
340
341 /* for pinctrl state changes, we need all the information */
342 if (bri->pins_default && bri->pins_gpio) {
343 dev_info(dev, "using pinctrl states for GPIO recovery");
344 } else {
345 bri->pinctrl = NULL;
346 bri->pins_default = NULL;
347 bri->pins_gpio = NULL;
348 }
349}
350
351static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
352{
353 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
354 struct device *dev = &adap->dev;
355 struct gpio_desc *gpiod;
356 int ret = 0;
357
358 /*
359 * don't touch the recovery information if the driver is not using
360 * generic SCL recovery
361 */
362 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
363 return 0;
364
365 /*
366 * pins might be taken as GPIO, so we should inform pinctrl about
367 * this and move the state to GPIO
368 */
369 if (bri->pinctrl)
370 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
371
372 /*
373 * if there is incomplete or no recovery information, see if generic
374 * GPIO recovery is available
375 */
376 if (!bri->scl_gpiod) {
377 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
378 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
379 ret = -EPROBE_DEFER;
380 goto cleanup_pinctrl_state;
381 }
382 if (!IS_ERR(gpiod)) {
383 bri->scl_gpiod = gpiod;
384 bri->recover_bus = i2c_generic_scl_recovery;
385 dev_info(dev, "using generic GPIOs for recovery\n");
386 }
387 }
388
389 /* SDA GPIOD line is optional, so we care about DEFER only */
390 if (!bri->sda_gpiod) {
391 /*
392 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
393 * have no effect.
394 */
395 gpiod_direction_output(bri->scl_gpiod, 0);
396 udelay(10);
397 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
398
399 /* Wait a bit in case of a SDA glitch, and then release SCL. */
400 udelay(10);
401 gpiod_direction_output(bri->scl_gpiod, 1);
402
403 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
404 ret = -EPROBE_DEFER;
405 goto cleanup_pinctrl_state;
406 }
407 if (!IS_ERR(gpiod))
408 bri->sda_gpiod = gpiod;
409 }
410
411cleanup_pinctrl_state:
412 /* change the state of the pins back to their default state */
413 if (bri->pinctrl)
414 pinctrl_select_state(bri->pinctrl, bri->pins_default);
415
416 return ret;
417}
418
419static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
420{
421 i2c_gpio_init_pinctrl_recovery(adap);
422 return i2c_gpio_init_generic_recovery(adap);
423}
424
425static int i2c_init_recovery(struct i2c_adapter *adap)
426{
427 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
428 bool is_error_level = true;
429 char *err_str;
430
431 if (!bri)
432 return 0;
433
434 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
435 return -EPROBE_DEFER;
436
437 if (!bri->recover_bus) {
438 err_str = "no suitable method provided";
439 is_error_level = false;
440 goto err;
441 }
442
443 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
444 bri->get_scl = get_scl_gpio_value;
445 bri->set_scl = set_scl_gpio_value;
446 if (bri->sda_gpiod) {
447 bri->get_sda = get_sda_gpio_value;
448 if (gpiod_get_direction(bri->sda_gpiod) == GPIO_LINE_DIRECTION_OUT)
449 bri->set_sda = set_sda_gpio_value;
450 }
451 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
452 /* Generic SCL recovery */
453 if (!bri->set_scl || !bri->get_scl) {
454 err_str = "no {get|set}_scl() found";
455 goto err;
456 }
457 if (!bri->set_sda && !bri->get_sda) {
458 err_str = "either get_sda() or set_sda() needed";
459 goto err;
460 }
461 }
462
463 return 0;
464 err:
465 if (is_error_level)
466 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
467 else
468 dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
469 adap->bus_recovery_info = NULL;
470
471 return -EINVAL;
472}
473
474static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
475{
476 struct i2c_adapter *adap = client->adapter;
477 unsigned int irq;
478
479 if (!adap->host_notify_domain)
480 return -ENXIO;
481
482 if (client->flags & I2C_CLIENT_TEN)
483 return -EINVAL;
484
485 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
486
487 return irq > 0 ? irq : -ENXIO;
488}
489
490static int i2c_device_probe(struct device *dev)
491{
492 struct fwnode_handle *fwnode = dev_fwnode(dev);
493 struct i2c_client *client = i2c_verify_client(dev);
494 struct i2c_driver *driver;
495 bool do_power_on;
496 int status;
497
498 if (!client)
499 return 0;
500
501 client->irq = client->init_irq;
502
503 if (!client->irq) {
504 int irq = -ENOENT;
505
506 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
507 dev_dbg(dev, "Using Host Notify IRQ\n");
508 /* Keep adapter active when Host Notify is required */
509 pm_runtime_get_sync(&client->adapter->dev);
510 irq = i2c_smbus_host_notify_to_irq(client);
511 } else if (is_of_node(fwnode)) {
512 irq = fwnode_irq_get_byname(fwnode, "irq");
513 if (irq == -EINVAL || irq == -ENODATA)
514 irq = fwnode_irq_get(fwnode, 0);
515 } else if (is_acpi_device_node(fwnode)) {
516 bool wake_capable;
517
518 irq = i2c_acpi_get_irq(client, &wake_capable);
519 if (irq > 0 && wake_capable)
520 client->flags |= I2C_CLIENT_WAKE;
521 }
522 if (irq == -EPROBE_DEFER) {
523 status = dev_err_probe(dev, irq, "can't get irq\n");
524 goto put_sync_adapter;
525 }
526
527 if (irq < 0)
528 irq = 0;
529
530 client->irq = irq;
531 }
532
533 driver = to_i2c_driver(dev->driver);
534
535 /*
536 * An I2C ID table is not mandatory, if and only if, a suitable OF
537 * or ACPI ID table is supplied for the probing device.
538 */
539 if (!driver->id_table &&
540 !acpi_driver_match_device(dev, dev->driver) &&
541 !i2c_of_match_device(dev->driver->of_match_table, client)) {
542 status = -ENODEV;
543 goto put_sync_adapter;
544 }
545
546 if (client->flags & I2C_CLIENT_WAKE) {
547 int wakeirq;
548
549 wakeirq = fwnode_irq_get_byname(fwnode, "wakeup");
550 if (wakeirq == -EPROBE_DEFER) {
551 status = dev_err_probe(dev, wakeirq, "can't get wakeirq\n");
552 goto put_sync_adapter;
553 }
554
555 device_init_wakeup(&client->dev, true);
556
557 if (wakeirq > 0 && wakeirq != client->irq)
558 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
559 else if (client->irq > 0)
560 status = dev_pm_set_wake_irq(dev, client->irq);
561 else
562 status = 0;
563
564 if (status)
565 dev_warn(&client->dev, "failed to set up wakeup irq\n");
566 }
567
568 dev_dbg(dev, "probe\n");
569
570 status = of_clk_set_defaults(to_of_node(fwnode), false);
571 if (status < 0)
572 goto err_clear_wakeup_irq;
573
574 do_power_on = !i2c_acpi_waive_d0_probe(dev);
575 status = dev_pm_domain_attach(&client->dev, PD_FLAG_DETACH_POWER_OFF |
576 (do_power_on ? PD_FLAG_ATTACH_POWER_ON : 0));
577 if (status)
578 goto err_clear_wakeup_irq;
579
580 client->devres_group_id = devres_open_group(&client->dev, NULL,
581 GFP_KERNEL);
582 if (!client->devres_group_id) {
583 status = -ENOMEM;
584 goto err_clear_wakeup_irq;
585 }
586
587 client->debugfs = debugfs_create_dir(dev_name(&client->dev),
588 client->adapter->debugfs);
589
590 if (driver->probe)
591 status = driver->probe(client);
592 else
593 status = -EINVAL;
594
595 /*
596 * Note that we are not closing the devres group opened above so
597 * even resources that were attached to the device after probe is
598 * run are released when i2c_device_remove() is executed. This is
599 * needed as some drivers would allocate additional resources,
600 * for example when updating firmware.
601 */
602
603 if (status)
604 goto err_release_driver_resources;
605
606 return 0;
607
608err_release_driver_resources:
609 debugfs_remove_recursive(client->debugfs);
610 devres_release_group(&client->dev, client->devres_group_id);
611err_clear_wakeup_irq:
612 dev_pm_clear_wake_irq(&client->dev);
613 device_init_wakeup(&client->dev, false);
614put_sync_adapter:
615 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
616 pm_runtime_put_sync(&client->adapter->dev);
617
618 return status;
619}
620
621static void i2c_device_remove(struct device *dev)
622{
623 struct i2c_client *client = to_i2c_client(dev);
624 struct i2c_driver *driver;
625
626 driver = to_i2c_driver(dev->driver);
627 if (driver->remove) {
628 dev_dbg(dev, "remove\n");
629
630 driver->remove(client);
631 }
632
633 debugfs_remove_recursive(client->debugfs);
634
635 devres_release_group(&client->dev, client->devres_group_id);
636
637 dev_pm_clear_wake_irq(&client->dev);
638 device_init_wakeup(&client->dev, false);
639
640 client->irq = 0;
641 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
642 pm_runtime_put(&client->adapter->dev);
643}
644
645static void i2c_device_shutdown(struct device *dev)
646{
647 struct i2c_client *client = i2c_verify_client(dev);
648 struct i2c_driver *driver;
649
650 if (!client || !dev->driver)
651 return;
652 driver = to_i2c_driver(dev->driver);
653 if (driver->shutdown)
654 driver->shutdown(client);
655 else if (client->irq > 0)
656 disable_irq(client->irq);
657}
658
659static void i2c_client_dev_release(struct device *dev)
660{
661 kfree(to_i2c_client(dev));
662}
663
664static ssize_t
665name_show(struct device *dev, struct device_attribute *attr, char *buf)
666{
667 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
668 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
669}
670static DEVICE_ATTR_RO(name);
671
672static ssize_t
673modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
674{
675 struct i2c_client *client = to_i2c_client(dev);
676 int len;
677
678 len = of_device_modalias(dev, buf, PAGE_SIZE);
679 if (len != -ENODEV)
680 return len;
681
682 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
683 if (len != -ENODEV)
684 return len;
685
686 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
687}
688static DEVICE_ATTR_RO(modalias);
689
690static struct attribute *i2c_dev_attrs[] = {
691 &dev_attr_name.attr,
692 /* modalias helps coldplug: modprobe $(cat .../modalias) */
693 &dev_attr_modalias.attr,
694 NULL
695};
696ATTRIBUTE_GROUPS(i2c_dev);
697
698const struct bus_type i2c_bus_type = {
699 .name = "i2c",
700 .match = i2c_device_match,
701 .probe = i2c_device_probe,
702 .remove = i2c_device_remove,
703 .shutdown = i2c_device_shutdown,
704};
705EXPORT_SYMBOL_GPL(i2c_bus_type);
706
707const struct device_type i2c_client_type = {
708 .groups = i2c_dev_groups,
709 .uevent = i2c_device_uevent,
710 .release = i2c_client_dev_release,
711};
712EXPORT_SYMBOL_GPL(i2c_client_type);
713
714
715/**
716 * i2c_verify_client - return parameter as i2c_client, or NULL
717 * @dev: device, probably from some driver model iterator
718 *
719 * When traversing the driver model tree, perhaps using driver model
720 * iterators like @device_for_each_child(), you can't assume very much
721 * about the nodes you find. Use this function to avoid oopses caused
722 * by wrongly treating some non-I2C device as an i2c_client.
723 */
724struct i2c_client *i2c_verify_client(struct device *dev)
725{
726 return (dev->type == &i2c_client_type)
727 ? to_i2c_client(dev)
728 : NULL;
729}
730EXPORT_SYMBOL(i2c_verify_client);
731
732
733/* Return a unique address which takes the flags of the client into account */
734static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
735{
736 unsigned short addr = client->addr;
737
738 /* For some client flags, add an arbitrary offset to avoid collisions */
739 if (client->flags & I2C_CLIENT_TEN)
740 addr |= I2C_ADDR_OFFSET_TEN_BIT;
741
742 if (client->flags & I2C_CLIENT_SLAVE)
743 addr |= I2C_ADDR_OFFSET_SLAVE;
744
745 return addr;
746}
747
748/* This is a permissive address validity check, I2C address map constraints
749 * are purposely not enforced, except for the general call address. */
750static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
751{
752 if (flags & I2C_CLIENT_TEN) {
753 /* 10-bit address, all values are valid */
754 if (addr > 0x3ff)
755 return -EINVAL;
756 } else {
757 /* 7-bit address, reject the general call address */
758 if (addr == 0x00 || addr > 0x7f)
759 return -EINVAL;
760 }
761 return 0;
762}
763
764/* And this is a strict address validity check, used when probing. If a
765 * device uses a reserved address, then it shouldn't be probed. 7-bit
766 * addressing is assumed, 10-bit address devices are rare and should be
767 * explicitly enumerated. */
768int i2c_check_7bit_addr_validity_strict(unsigned short addr)
769{
770 /*
771 * Reserved addresses per I2C specification:
772 * 0x00 General call address / START byte
773 * 0x01 CBUS address
774 * 0x02 Reserved for different bus format
775 * 0x03 Reserved for future purposes
776 * 0x04-0x07 Hs-mode master code
777 * 0x78-0x7b 10-bit slave addressing
778 * 0x7c-0x7f Reserved for future purposes
779 */
780 if (addr < 0x08 || addr > 0x77)
781 return -EINVAL;
782 return 0;
783}
784
785static int __i2c_check_addr_busy(struct device *dev, void *addrp)
786{
787 struct i2c_client *client = i2c_verify_client(dev);
788 int addr = *(int *)addrp;
789
790 if (client && i2c_encode_flags_to_addr(client) == addr)
791 return -EBUSY;
792 return 0;
793}
794
795/* walk up mux tree */
796static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
797{
798 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
799 int result;
800
801 result = device_for_each_child(&adapter->dev, &addr,
802 __i2c_check_addr_busy);
803
804 if (!result && parent)
805 result = i2c_check_mux_parents(parent, addr);
806
807 return result;
808}
809
810/* recurse down mux tree */
811static int i2c_check_mux_children(struct device *dev, void *addrp)
812{
813 int result;
814
815 if (dev->type == &i2c_adapter_type)
816 result = device_for_each_child(dev, addrp,
817 i2c_check_mux_children);
818 else
819 result = __i2c_check_addr_busy(dev, addrp);
820
821 return result;
822}
823
824static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
825{
826 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
827 int result = 0;
828
829 if (parent)
830 result = i2c_check_mux_parents(parent, addr);
831
832 if (!result)
833 result = device_for_each_child(&adapter->dev, &addr,
834 i2c_check_mux_children);
835
836 return result;
837}
838
839/**
840 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
841 * @adapter: Target I2C bus segment
842 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
843 * locks only this branch in the adapter tree
844 */
845static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
846 unsigned int flags)
847{
848 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
849}
850
851/**
852 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
853 * @adapter: Target I2C bus segment
854 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
855 * trylocks only this branch in the adapter tree
856 */
857static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
858 unsigned int flags)
859{
860 return rt_mutex_trylock(&adapter->bus_lock);
861}
862
863/**
864 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
865 * @adapter: Target I2C bus segment
866 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
867 * unlocks only this branch in the adapter tree
868 */
869static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
870 unsigned int flags)
871{
872 rt_mutex_unlock(&adapter->bus_lock);
873}
874
875static void i2c_dev_set_name(struct i2c_adapter *adap,
876 struct i2c_client *client,
877 struct i2c_board_info const *info)
878{
879 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
880
881 if (info && info->dev_name) {
882 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
883 return;
884 }
885
886 if (adev) {
887 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
888 return;
889 }
890
891 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
892 i2c_encode_flags_to_addr(client));
893}
894
895int i2c_dev_irq_from_resources(const struct resource *resources,
896 unsigned int num_resources)
897{
898 struct irq_data *irqd;
899 int i;
900
901 for (i = 0; i < num_resources; i++) {
902 const struct resource *r = &resources[i];
903
904 if (resource_type(r) != IORESOURCE_IRQ)
905 continue;
906
907 if (r->flags & IORESOURCE_BITS) {
908 irqd = irq_get_irq_data(r->start);
909 if (!irqd)
910 break;
911
912 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
913 }
914
915 return r->start;
916 }
917
918 return 0;
919}
920
921/*
922 * Serialize device instantiation in case it can be instantiated explicitly
923 * and by auto-detection
924 */
925static int i2c_lock_addr(struct i2c_adapter *adap, unsigned short addr,
926 unsigned short flags)
927{
928 if (!(flags & I2C_CLIENT_TEN) &&
929 test_and_set_bit(addr, adap->addrs_in_instantiation))
930 return -EBUSY;
931
932 return 0;
933}
934
935static void i2c_unlock_addr(struct i2c_adapter *adap, unsigned short addr,
936 unsigned short flags)
937{
938 if (!(flags & I2C_CLIENT_TEN))
939 clear_bit(addr, adap->addrs_in_instantiation);
940}
941
942/**
943 * i2c_new_client_device - instantiate an i2c device
944 * @adap: the adapter managing the device
945 * @info: describes one I2C device; bus_num is ignored
946 * Context: can sleep
947 *
948 * Create an i2c device. Binding is handled through driver model
949 * probe()/remove() methods. A driver may be bound to this device when we
950 * return from this function, or any later moment (e.g. maybe hotplugging will
951 * load the driver module). This call is not appropriate for use by mainboard
952 * initialization logic, which usually runs during an arch_initcall() long
953 * before any i2c_adapter could exist.
954 *
955 * This returns the new i2c client, which may be saved for later use with
956 * i2c_unregister_device(); or an ERR_PTR to describe the error.
957 */
958struct i2c_client *
959i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
960{
961 struct fwnode_handle *fwnode = info->fwnode;
962 struct i2c_client *client;
963 bool need_put = false;
964 int status;
965
966 client = kzalloc_obj(*client);
967 if (!client)
968 return ERR_PTR(-ENOMEM);
969
970 client->adapter = adap;
971
972 client->dev.platform_data = info->platform_data;
973 client->flags = info->flags;
974 client->addr = info->addr;
975
976 client->init_irq = info->irq;
977 if (!client->init_irq)
978 client->init_irq = i2c_dev_irq_from_resources(info->resources,
979 info->num_resources);
980
981 strscpy(client->name, info->type, sizeof(client->name));
982
983 status = i2c_check_addr_validity(client->addr, client->flags);
984 if (status) {
985 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
986 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
987 goto out_err_silent;
988 }
989
990 status = i2c_lock_addr(adap, client->addr, client->flags);
991 if (status)
992 goto out_err_silent;
993
994 /* Check for address business */
995 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
996 if (status)
997 goto out_err;
998
999 client->dev.parent = &client->adapter->dev;
1000 client->dev.bus = &i2c_bus_type;
1001 client->dev.type = &i2c_client_type;
1002
1003 device_enable_async_suspend(&client->dev);
1004
1005 device_set_node(&client->dev, fwnode_handle_get(fwnode));
1006
1007 if (info->swnode) {
1008 status = device_add_software_node(&client->dev, info->swnode);
1009 if (status) {
1010 dev_err(&adap->dev,
1011 "Failed to add software node to client %s: %d\n",
1012 client->name, status);
1013 goto out_err_put_fwnode;
1014 }
1015 }
1016
1017 i2c_dev_set_name(adap, client, info);
1018 status = device_register(&client->dev);
1019 if (status)
1020 goto out_remove_swnode;
1021
1022 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1023 client->name, dev_name(&client->dev));
1024
1025 i2c_unlock_addr(adap, client->addr, client->flags);
1026
1027 return client;
1028
1029out_remove_swnode:
1030 device_remove_software_node(&client->dev);
1031 need_put = true;
1032out_err_put_fwnode:
1033 fwnode_handle_put(fwnode);
1034out_err:
1035 dev_err(&adap->dev,
1036 "Failed to register i2c client %s at 0x%02x (%d)\n",
1037 client->name, client->addr, status);
1038 i2c_unlock_addr(adap, client->addr, client->flags);
1039out_err_silent:
1040 if (need_put)
1041 put_device(&client->dev);
1042 else
1043 kfree(client);
1044 return ERR_PTR(status);
1045}
1046EXPORT_SYMBOL_GPL(i2c_new_client_device);
1047
1048/**
1049 * i2c_unregister_device - reverse effect of i2c_new_*_device()
1050 * @client: value returned from i2c_new_*_device()
1051 * Context: can sleep
1052 */
1053void i2c_unregister_device(struct i2c_client *client)
1054{
1055 struct fwnode_handle *fwnode;
1056
1057 if (IS_ERR_OR_NULL(client))
1058 return;
1059
1060 fwnode = dev_fwnode(&client->dev);
1061 if (is_of_node(fwnode))
1062 of_node_clear_flag(to_of_node(fwnode), OF_POPULATED);
1063 else if (is_acpi_device_node(fwnode))
1064 acpi_device_clear_enumerated(to_acpi_device_node(fwnode));
1065
1066 /*
1067 * If the primary fwnode is a software node it is free-ed by
1068 * device_remove_software_node() below, avoid double-free.
1069 */
1070 if (!is_software_node(fwnode))
1071 fwnode_handle_put(fwnode);
1072
1073 device_remove_software_node(&client->dev);
1074 device_unregister(&client->dev);
1075}
1076EXPORT_SYMBOL_GPL(i2c_unregister_device);
1077
1078/**
1079 * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1080 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1081 *
1082 * Look up and return the &struct i2c_client corresponding to the @fwnode.
1083 * If no client can be found, or @fwnode is NULL, this returns NULL.
1084 *
1085 * The user must call put_device(&client->dev) once done with the i2c client.
1086 */
1087struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1088{
1089 struct i2c_client *client;
1090 struct device *dev;
1091
1092 if (IS_ERR_OR_NULL(fwnode))
1093 return NULL;
1094
1095 dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1096 if (!dev)
1097 return NULL;
1098
1099 client = i2c_verify_client(dev);
1100 if (!client)
1101 put_device(dev);
1102
1103 return client;
1104}
1105EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1106
1107
1108static const struct i2c_device_id dummy_id[] = {
1109 { "dummy", },
1110 { "smbus_host_notify", },
1111 { }
1112};
1113
1114static int dummy_probe(struct i2c_client *client)
1115{
1116 return 0;
1117}
1118
1119static struct i2c_driver dummy_driver = {
1120 .driver.name = "dummy",
1121 .probe = dummy_probe,
1122 .id_table = dummy_id,
1123};
1124
1125/**
1126 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1127 * @adapter: the adapter managing the device
1128 * @address: seven bit address to be used
1129 * Context: can sleep
1130 *
1131 * This returns an I2C client bound to the "dummy" driver, intended for use
1132 * with devices that consume multiple addresses. Examples of such chips
1133 * include various EEPROMS (like 24c04 and 24c08 models).
1134 *
1135 * These dummy devices have two main uses. First, most I2C and SMBus calls
1136 * except i2c_transfer() need a client handle; the dummy will be that handle.
1137 * And second, this prevents the specified address from being bound to a
1138 * different driver.
1139 *
1140 * This returns the new i2c client, which should be saved for later use with
1141 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1142 */
1143struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1144{
1145 struct i2c_board_info info = {
1146 I2C_BOARD_INFO("dummy", address),
1147 };
1148
1149 return i2c_new_client_device(adapter, &info);
1150}
1151EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1152
1153static void devm_i2c_release_dummy(void *client)
1154{
1155 i2c_unregister_device(client);
1156}
1157
1158/**
1159 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1160 * @dev: device the managed resource is bound to
1161 * @adapter: the adapter managing the device
1162 * @address: seven bit address to be used
1163 * Context: can sleep
1164 *
1165 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1166 * new i2c client or an ERR_PTR in case of an error.
1167 */
1168struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1169 struct i2c_adapter *adapter,
1170 u16 address)
1171{
1172 struct i2c_client *client;
1173 int ret;
1174
1175 client = i2c_new_dummy_device(adapter, address);
1176 if (IS_ERR(client))
1177 return client;
1178
1179 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1180 if (ret)
1181 return ERR_PTR(ret);
1182
1183 return client;
1184}
1185EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1186
1187/**
1188 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1189 * and create the associated device
1190 * @client: Handle to the primary client
1191 * @name: Handle to specify which secondary address to get
1192 * @default_addr: Used as a fallback if no secondary address was specified
1193 * Context: can sleep
1194 *
1195 * I2C clients can be composed of multiple I2C slaves bound together in a single
1196 * component. The I2C client driver then binds to the master I2C slave and needs
1197 * to create I2C dummy clients to communicate with all the other slaves.
1198 *
1199 * This function creates and returns an I2C dummy client whose I2C address is
1200 * retrieved from the platform firmware based on the given slave name. If no
1201 * address is specified by the firmware default_addr is used.
1202 *
1203 * On DT-based platforms the address is retrieved from the "reg" property entry
1204 * cell whose "reg-names" value matches the slave name.
1205 *
1206 * This returns the new i2c client, which should be saved for later use with
1207 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1208 */
1209struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1210 const char *name,
1211 u16 default_addr)
1212{
1213 struct device_node *np = client->dev.of_node;
1214 u32 addr = default_addr;
1215 int i;
1216
1217 i = of_property_match_string(np, "reg-names", name);
1218 if (i >= 0)
1219 of_property_read_u32_index(np, "reg", i, &addr);
1220
1221 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1222 return i2c_new_dummy_device(client->adapter, addr);
1223}
1224EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1225
1226/* ------------------------------------------------------------------------- */
1227
1228/* I2C bus adapters -- one roots each I2C or SMBUS segment */
1229
1230static void i2c_adapter_dev_release(struct device *dev)
1231{
1232 struct i2c_adapter *adap = to_i2c_adapter(dev);
1233 complete(&adap->dev_released);
1234}
1235
1236unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1237{
1238 unsigned int depth = 0;
1239 struct device *parent;
1240
1241 for (parent = adapter->dev.parent; parent; parent = parent->parent)
1242 if (parent->type == &i2c_adapter_type)
1243 depth++;
1244
1245 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1246 "adapter depth exceeds lockdep subclass limit\n");
1247
1248 return depth;
1249}
1250EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1251
1252/*
1253 * Let users instantiate I2C devices through sysfs. This can be used when
1254 * platform initialization code doesn't contain the proper data for
1255 * whatever reason. Also useful for drivers that do device detection and
1256 * detection fails, either because the device uses an unexpected address,
1257 * or this is a compatible device with different ID register values.
1258 *
1259 * Parameter checking may look overzealous, but we really don't want
1260 * the user to provide incorrect parameters.
1261 */
1262static ssize_t
1263new_device_store(struct device *dev, struct device_attribute *attr,
1264 const char *buf, size_t count)
1265{
1266 struct i2c_adapter *adap = to_i2c_adapter(dev);
1267 struct i2c_board_info info;
1268 struct i2c_client *client;
1269 char *blank, end;
1270 int res;
1271
1272 memset(&info, 0, sizeof(struct i2c_board_info));
1273
1274 blank = strchr(buf, ' ');
1275 if (!blank) {
1276 dev_err(dev, "%s: Missing parameters\n", "new_device");
1277 return -EINVAL;
1278 }
1279 if (blank - buf > I2C_NAME_SIZE - 1) {
1280 dev_err(dev, "%s: Invalid device name\n", "new_device");
1281 return -EINVAL;
1282 }
1283 memcpy(info.type, buf, blank - buf);
1284
1285 /* Parse remaining parameters, reject extra parameters */
1286 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1287 if (res < 1) {
1288 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1289 return -EINVAL;
1290 }
1291 if (res > 1 && end != '\n') {
1292 dev_err(dev, "%s: Extra parameters\n", "new_device");
1293 return -EINVAL;
1294 }
1295
1296 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1297 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1298 info.flags |= I2C_CLIENT_TEN;
1299 }
1300
1301 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1302 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1303 info.flags |= I2C_CLIENT_SLAVE;
1304 }
1305
1306 client = i2c_new_client_device(adap, &info);
1307 if (IS_ERR(client))
1308 return PTR_ERR(client);
1309
1310 /* Keep track of the added device */
1311 mutex_lock(&adap->userspace_clients_lock);
1312 list_add_tail(&client->detected, &adap->userspace_clients);
1313 mutex_unlock(&adap->userspace_clients_lock);
1314 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1315 info.type, info.addr);
1316
1317 return count;
1318}
1319static DEVICE_ATTR_WO(new_device);
1320
1321/*
1322 * And of course let the users delete the devices they instantiated, if
1323 * they got it wrong. This interface can only be used to delete devices
1324 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1325 * don't delete devices to which some kernel code still has references.
1326 *
1327 * Parameter checking may look overzealous, but we really don't want
1328 * the user to delete the wrong device.
1329 */
1330static ssize_t
1331delete_device_store(struct device *dev, struct device_attribute *attr,
1332 const char *buf, size_t count)
1333{
1334 struct i2c_adapter *adap = to_i2c_adapter(dev);
1335 struct i2c_client *client, *next;
1336 unsigned short addr;
1337 char end;
1338 int res;
1339
1340 /* Parse parameters, reject extra parameters */
1341 res = sscanf(buf, "%hi%c", &addr, &end);
1342 if (res < 1) {
1343 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1344 return -EINVAL;
1345 }
1346 if (res > 1 && end != '\n') {
1347 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1348 return -EINVAL;
1349 }
1350
1351 /* Make sure the device was added through sysfs */
1352 res = -ENOENT;
1353 mutex_lock_nested(&adap->userspace_clients_lock,
1354 i2c_adapter_depth(adap));
1355 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1356 detected) {
1357 if (i2c_encode_flags_to_addr(client) == addr) {
1358 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1359 "delete_device", client->name, client->addr);
1360
1361 list_del(&client->detected);
1362 i2c_unregister_device(client);
1363 res = count;
1364 break;
1365 }
1366 }
1367 mutex_unlock(&adap->userspace_clients_lock);
1368
1369 if (res < 0)
1370 dev_err(dev, "%s: Can't find device in list\n",
1371 "delete_device");
1372 return res;
1373}
1374static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1375 delete_device_store);
1376
1377static struct attribute *i2c_adapter_attrs[] = {
1378 &dev_attr_name.attr,
1379 &dev_attr_new_device.attr,
1380 &dev_attr_delete_device.attr,
1381 NULL
1382};
1383ATTRIBUTE_GROUPS(i2c_adapter);
1384
1385const struct device_type i2c_adapter_type = {
1386 .groups = i2c_adapter_groups,
1387 .release = i2c_adapter_dev_release,
1388};
1389EXPORT_SYMBOL_GPL(i2c_adapter_type);
1390
1391/**
1392 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1393 * @dev: device, probably from some driver model iterator
1394 *
1395 * When traversing the driver model tree, perhaps using driver model
1396 * iterators like @device_for_each_child(), you can't assume very much
1397 * about the nodes you find. Use this function to avoid oopses caused
1398 * by wrongly treating some non-I2C device as an i2c_adapter.
1399 */
1400struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1401{
1402 return (dev->type == &i2c_adapter_type)
1403 ? to_i2c_adapter(dev)
1404 : NULL;
1405}
1406EXPORT_SYMBOL(i2c_verify_adapter);
1407
1408static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1409{
1410 struct i2c_devinfo *devinfo;
1411
1412 down_read(&__i2c_board_lock);
1413 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1414 if (devinfo->busnum == adapter->nr &&
1415 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1416 dev_err(&adapter->dev,
1417 "Can't create device at 0x%02x\n",
1418 devinfo->board_info.addr);
1419 }
1420 up_read(&__i2c_board_lock);
1421}
1422
1423static int i2c_do_add_adapter(struct i2c_driver *driver,
1424 struct i2c_adapter *adap)
1425{
1426 /* Detect supported devices on that bus, and instantiate them */
1427 i2c_detect(adap, driver);
1428
1429 return 0;
1430}
1431
1432static int __process_new_adapter(struct device_driver *d, void *data)
1433{
1434 return i2c_do_add_adapter(to_i2c_driver(d), data);
1435}
1436
1437static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1438 .lock_bus = i2c_adapter_lock_bus,
1439 .trylock_bus = i2c_adapter_trylock_bus,
1440 .unlock_bus = i2c_adapter_unlock_bus,
1441};
1442
1443static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1444{
1445 struct irq_domain *domain = adap->host_notify_domain;
1446 irq_hw_number_t hwirq;
1447
1448 if (!domain)
1449 return;
1450
1451 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1452 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1453
1454 irq_domain_remove(domain);
1455 adap->host_notify_domain = NULL;
1456}
1457
1458static int i2c_host_notify_irq_map(struct irq_domain *h,
1459 unsigned int virq,
1460 irq_hw_number_t hw_irq_num)
1461{
1462 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1463
1464 return 0;
1465}
1466
1467static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1468 .map = i2c_host_notify_irq_map,
1469};
1470
1471static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1472{
1473 struct irq_domain *domain;
1474
1475 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1476 return 0;
1477
1478 domain = irq_domain_create_linear(dev_fwnode(adap->dev.parent),
1479 I2C_ADDR_7BITS_COUNT,
1480 &i2c_host_notify_irq_ops, adap);
1481 if (!domain)
1482 return -ENOMEM;
1483
1484 adap->host_notify_domain = domain;
1485
1486 return 0;
1487}
1488
1489/**
1490 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1491 * I2C client.
1492 * @adap: the adapter
1493 * @addr: the I2C address of the notifying device
1494 * Context: can't sleep
1495 *
1496 * Helper function to be called from an I2C bus driver's interrupt
1497 * handler. It will schedule the Host Notify IRQ.
1498 */
1499int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1500{
1501 int irq;
1502
1503 if (!adap)
1504 return -EINVAL;
1505
1506 dev_dbg(&adap->dev, "Detected HostNotify from address 0x%02x", addr);
1507
1508 irq = irq_find_mapping(adap->host_notify_domain, addr);
1509 if (irq <= 0)
1510 return -ENXIO;
1511
1512 generic_handle_irq_safe(irq);
1513
1514 return 0;
1515}
1516EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1517
1518static int i2c_register_adapter(struct i2c_adapter *adap)
1519{
1520 int res = -EINVAL;
1521
1522 /* Can't register until after driver model init */
1523 if (WARN_ON(!is_registered)) {
1524 res = -EAGAIN;
1525 goto out_list;
1526 }
1527
1528 /* Sanity checks */
1529 if (WARN(!adap->name[0], "i2c adapter has no name"))
1530 goto out_list;
1531
1532 if (!adap->algo) {
1533 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1534 goto out_list;
1535 }
1536
1537 if (!adap->lock_ops)
1538 adap->lock_ops = &i2c_adapter_lock_ops;
1539
1540 adap->locked_flags = 0;
1541 rt_mutex_init(&adap->bus_lock);
1542 rt_mutex_init(&adap->mux_lock);
1543 mutex_init(&adap->userspace_clients_lock);
1544 INIT_LIST_HEAD(&adap->userspace_clients);
1545
1546 /* Set default timeout to 1 second if not already set */
1547 if (adap->timeout == 0)
1548 adap->timeout = HZ;
1549
1550 /* register soft irqs for Host Notify */
1551 res = i2c_setup_host_notify_irq_domain(adap);
1552 if (res) {
1553 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1554 adap->name, res);
1555 goto out_list;
1556 }
1557
1558 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1559 adap->dev.bus = &i2c_bus_type;
1560 adap->dev.type = &i2c_adapter_type;
1561 device_initialize(&adap->dev);
1562
1563 /*
1564 * This adapter can be used as a parent immediately after device_add(),
1565 * setup runtime-pm (especially ignore-children) before hand.
1566 */
1567 device_enable_async_suspend(&adap->dev);
1568 pm_runtime_no_callbacks(&adap->dev);
1569 pm_suspend_ignore_children(&adap->dev, true);
1570 pm_runtime_enable(&adap->dev);
1571
1572 res = device_add(&adap->dev);
1573 if (res) {
1574 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1575 put_device(&adap->dev);
1576 goto out_list;
1577 }
1578
1579 adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root);
1580
1581 res = i2c_setup_smbus_alert(adap);
1582 if (res)
1583 goto out_reg;
1584
1585 res = i2c_init_recovery(adap);
1586 if (res == -EPROBE_DEFER)
1587 goto out_reg;
1588
1589 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1590
1591 /* create pre-declared device nodes */
1592 of_i2c_register_devices(adap);
1593 i2c_acpi_install_space_handler(adap);
1594 i2c_acpi_register_devices(adap);
1595
1596 if (adap->nr < __i2c_first_dynamic_bus_num)
1597 i2c_scan_static_board_info(adap);
1598
1599 /* Notify drivers */
1600 mutex_lock(&core_lock);
1601 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1602 mutex_unlock(&core_lock);
1603
1604 return 0;
1605
1606out_reg:
1607 debugfs_remove_recursive(adap->debugfs);
1608 init_completion(&adap->dev_released);
1609 device_unregister(&adap->dev);
1610 wait_for_completion(&adap->dev_released);
1611out_list:
1612 mutex_lock(&core_lock);
1613 idr_remove(&i2c_adapter_idr, adap->nr);
1614 mutex_unlock(&core_lock);
1615 return res;
1616}
1617
1618/**
1619 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1620 * @adap: the adapter to register (with adap->nr initialized)
1621 * Context: can sleep
1622 *
1623 * See i2c_add_numbered_adapter() for details.
1624 */
1625static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1626{
1627 int id;
1628
1629 mutex_lock(&core_lock);
1630 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1631 mutex_unlock(&core_lock);
1632 if (WARN(id < 0, "couldn't get idr"))
1633 return id == -ENOSPC ? -EBUSY : id;
1634
1635 return i2c_register_adapter(adap);
1636}
1637
1638/**
1639 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1640 * @adapter: the adapter to add
1641 * Context: can sleep
1642 *
1643 * This routine is used to declare an I2C adapter when its bus number
1644 * doesn't matter or when its bus number is specified by an dt alias.
1645 * Examples of bases when the bus number doesn't matter: I2C adapters
1646 * dynamically added by USB links or PCI plugin cards.
1647 *
1648 * When this returns zero, a new bus number was allocated and stored
1649 * in adap->nr, and the specified adapter became available for clients.
1650 * Otherwise, a negative errno value is returned.
1651 */
1652int i2c_add_adapter(struct i2c_adapter *adapter)
1653{
1654 struct device *dev = &adapter->dev;
1655 int id;
1656
1657 id = of_alias_get_id(dev->of_node, "i2c");
1658 if (id >= 0) {
1659 adapter->nr = id;
1660 return __i2c_add_numbered_adapter(adapter);
1661 }
1662
1663 mutex_lock(&core_lock);
1664 id = idr_alloc(&i2c_adapter_idr, adapter,
1665 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1666 mutex_unlock(&core_lock);
1667 if (WARN(id < 0, "couldn't get idr"))
1668 return id;
1669
1670 adapter->nr = id;
1671
1672 return i2c_register_adapter(adapter);
1673}
1674EXPORT_SYMBOL(i2c_add_adapter);
1675
1676/**
1677 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1678 * @adap: the adapter to register (with adap->nr initialized)
1679 * Context: can sleep
1680 *
1681 * This routine is used to declare an I2C adapter when its bus number
1682 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1683 * or otherwise built in to the system's mainboard, and where i2c_board_info
1684 * is used to properly configure I2C devices.
1685 *
1686 * If the requested bus number is set to -1, then this function will behave
1687 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1688 *
1689 * If no devices have pre-been declared for this bus, then be sure to
1690 * register the adapter before any dynamically allocated ones. Otherwise
1691 * the required bus ID may not be available.
1692 *
1693 * When this returns zero, the specified adapter became available for
1694 * clients using the bus number provided in adap->nr. Also, the table
1695 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1696 * and the appropriate driver model device nodes are created. Otherwise, a
1697 * negative errno value is returned.
1698 */
1699int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1700{
1701 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1702 return i2c_add_adapter(adap);
1703
1704 return __i2c_add_numbered_adapter(adap);
1705}
1706EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1707
1708static void i2c_do_del_adapter(struct i2c_driver *driver,
1709 struct i2c_adapter *adapter)
1710{
1711 struct i2c_client *client, *_n;
1712
1713 /* Remove the devices we created ourselves as the result of hardware
1714 * probing (using a driver's detect method) */
1715 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1716 if (client->adapter == adapter) {
1717 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1718 client->name, client->addr);
1719 list_del(&client->detected);
1720 i2c_unregister_device(client);
1721 }
1722 }
1723}
1724
1725static int __unregister_client(struct device *dev, void *dummy)
1726{
1727 struct i2c_client *client = i2c_verify_client(dev);
1728 if (client && strcmp(client->name, "dummy"))
1729 i2c_unregister_device(client);
1730 return 0;
1731}
1732
1733static int __unregister_dummy(struct device *dev, void *dummy)
1734{
1735 struct i2c_client *client = i2c_verify_client(dev);
1736 i2c_unregister_device(client);
1737 return 0;
1738}
1739
1740static int __process_removed_adapter(struct device_driver *d, void *data)
1741{
1742 i2c_do_del_adapter(to_i2c_driver(d), data);
1743 return 0;
1744}
1745
1746/**
1747 * i2c_del_adapter - unregister I2C adapter
1748 * @adap: the adapter being unregistered
1749 * Context: can sleep
1750 *
1751 * This unregisters an I2C adapter which was previously registered
1752 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1753 */
1754void i2c_del_adapter(struct i2c_adapter *adap)
1755{
1756 struct i2c_adapter *found;
1757 struct i2c_client *client, *next;
1758
1759 /* First make sure that this adapter was ever added */
1760 mutex_lock(&core_lock);
1761 found = idr_find(&i2c_adapter_idr, adap->nr);
1762 mutex_unlock(&core_lock);
1763 if (found != adap) {
1764 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1765 return;
1766 }
1767
1768 i2c_acpi_remove_space_handler(adap);
1769 /* Tell drivers about this removal */
1770 mutex_lock(&core_lock);
1771 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1772 __process_removed_adapter);
1773 mutex_unlock(&core_lock);
1774
1775 /* Remove devices instantiated from sysfs */
1776 mutex_lock_nested(&adap->userspace_clients_lock,
1777 i2c_adapter_depth(adap));
1778 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1779 detected) {
1780 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1781 client->addr);
1782 list_del(&client->detected);
1783 i2c_unregister_device(client);
1784 }
1785 mutex_unlock(&adap->userspace_clients_lock);
1786
1787 /* Detach any active clients. This can't fail, thus we do not
1788 * check the returned value. This is a two-pass process, because
1789 * we can't remove the dummy devices during the first pass: they
1790 * could have been instantiated by real devices wishing to clean
1791 * them up properly, so we give them a chance to do that first. */
1792 device_for_each_child(&adap->dev, NULL, __unregister_client);
1793 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1794
1795 /* device name is gone after device_unregister */
1796 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1797
1798 pm_runtime_disable(&adap->dev);
1799
1800 i2c_host_notify_irq_teardown(adap);
1801
1802 debugfs_remove_recursive(adap->debugfs);
1803
1804 /* wait until all references to the device are gone
1805 *
1806 * FIXME: This is old code and should ideally be replaced by an
1807 * alternative which results in decoupling the lifetime of the struct
1808 * device from the i2c_adapter, like spi or netdev do. Any solution
1809 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1810 */
1811 init_completion(&adap->dev_released);
1812 device_unregister(&adap->dev);
1813 wait_for_completion(&adap->dev_released);
1814
1815 /* free bus id */
1816 mutex_lock(&core_lock);
1817 idr_remove(&i2c_adapter_idr, adap->nr);
1818 mutex_unlock(&core_lock);
1819
1820 /* Clear the device structure in case this adapter is ever going to be
1821 added again */
1822 memset(&adap->dev, 0, sizeof(adap->dev));
1823}
1824EXPORT_SYMBOL(i2c_del_adapter);
1825
1826static void devm_i2c_del_adapter(void *adapter)
1827{
1828 i2c_del_adapter(adapter);
1829}
1830
1831/**
1832 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1833 * @dev: managing device for adding this I2C adapter
1834 * @adapter: the adapter to add
1835 * Context: can sleep
1836 *
1837 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1838 * but the adapter will be auto deleted on driver detach.
1839 */
1840int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1841{
1842 int ret;
1843
1844 ret = i2c_add_adapter(adapter);
1845 if (ret)
1846 return ret;
1847
1848 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1849}
1850EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1851
1852static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1853{
1854 if (device_match_fwnode(dev, data))
1855 return 1;
1856
1857 if (dev->parent && device_match_fwnode(dev->parent, data))
1858 return 1;
1859
1860 return 0;
1861}
1862
1863/**
1864 * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1865 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1866 *
1867 * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1868 * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1869 *
1870 * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1871 */
1872struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1873{
1874 struct i2c_adapter *adapter;
1875 struct device *dev;
1876
1877 if (IS_ERR_OR_NULL(fwnode))
1878 return NULL;
1879
1880 dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1881 i2c_dev_or_parent_fwnode_match);
1882 if (!dev)
1883 return NULL;
1884
1885 adapter = i2c_verify_adapter(dev);
1886 if (!adapter)
1887 put_device(dev);
1888
1889 return adapter;
1890}
1891EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1892
1893/**
1894 * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1895 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1896 *
1897 * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1898 * and increment the adapter module's use count. If no adapter can be found,
1899 * or @fwnode is NULL, this returns NULL.
1900 *
1901 * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1902 * Note that this is different from i2c_find_adapter_by_node().
1903 */
1904struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1905{
1906 struct i2c_adapter *adapter;
1907
1908 adapter = i2c_find_adapter_by_fwnode(fwnode);
1909 if (!adapter)
1910 return NULL;
1911
1912 if (!try_module_get(adapter->owner)) {
1913 put_device(&adapter->dev);
1914 adapter = NULL;
1915 }
1916
1917 return adapter;
1918}
1919EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1920
1921static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1922 u32 def_val, bool use_def)
1923{
1924 int ret;
1925
1926 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1927 if (ret && use_def)
1928 *cur_val_p = def_val;
1929
1930 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1931}
1932
1933/**
1934 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1935 * @dev: The device to scan for I2C timing properties
1936 * @t: the i2c_timings struct to be filled with values
1937 * @use_defaults: bool to use sane defaults derived from the I2C specification
1938 * when properties are not found, otherwise don't update
1939 *
1940 * Scan the device for the generic I2C properties describing timing parameters
1941 * for the signal and fill the given struct with the results. If a property was
1942 * not found and use_defaults was true, then maximum timings are assumed which
1943 * are derived from the I2C specification. If use_defaults is not used, the
1944 * results will be as before, so drivers can apply their own defaults before
1945 * calling this helper. The latter is mainly intended for avoiding regressions
1946 * of existing drivers which want to switch to this function. New drivers
1947 * almost always should use the defaults.
1948 */
1949void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1950{
1951 bool u = use_defaults;
1952 u32 d;
1953
1954 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1955 I2C_MAX_STANDARD_MODE_FREQ, u);
1956
1957 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1958 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1959 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1960
1961 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1962 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1963
1964 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1965 &t->scl_int_delay_ns, 0, u);
1966 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1967 t->scl_fall_ns, u);
1968 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1969 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1970 &t->digital_filter_width_ns, 0, u);
1971 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1972 &t->analog_filter_cutoff_freq_hz, 0, u);
1973}
1974EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1975
1976/* ------------------------------------------------------------------------- */
1977
1978int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1979{
1980 int res;
1981
1982 mutex_lock(&core_lock);
1983 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1984 mutex_unlock(&core_lock);
1985
1986 return res;
1987}
1988EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1989
1990static int __process_new_driver(struct device *dev, void *data)
1991{
1992 if (dev->type != &i2c_adapter_type)
1993 return 0;
1994 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1995}
1996
1997/*
1998 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1999 * i2c slave chips, on a bus instance associated with some i2c_adapter.
2000 */
2001
2002int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
2003{
2004 int res;
2005
2006 /* Can't register until after driver model init */
2007 if (WARN_ON(!is_registered))
2008 return -EAGAIN;
2009
2010 /* add the driver to the list of i2c drivers in the driver core */
2011 driver->driver.owner = owner;
2012 driver->driver.bus = &i2c_bus_type;
2013 INIT_LIST_HEAD(&driver->clients);
2014
2015 /* When registration returns, the driver core
2016 * will have called probe() for all matching-but-unbound devices.
2017 */
2018 res = driver_register(&driver->driver);
2019 if (res)
2020 return res;
2021
2022 pr_debug("driver [%s] registered\n", driver->driver.name);
2023
2024 /* Walk the adapters that are already present */
2025 i2c_for_each_dev(driver, __process_new_driver);
2026
2027 return 0;
2028}
2029EXPORT_SYMBOL(i2c_register_driver);
2030
2031static int __process_removed_driver(struct device *dev, void *data)
2032{
2033 if (dev->type == &i2c_adapter_type)
2034 i2c_do_del_adapter(data, to_i2c_adapter(dev));
2035 return 0;
2036}
2037
2038/**
2039 * i2c_del_driver - unregister I2C driver
2040 * @driver: the driver being unregistered
2041 * Context: can sleep
2042 */
2043void i2c_del_driver(struct i2c_driver *driver)
2044{
2045 i2c_for_each_dev(driver, __process_removed_driver);
2046
2047 driver_unregister(&driver->driver);
2048 pr_debug("driver [%s] unregistered\n", driver->driver.name);
2049}
2050EXPORT_SYMBOL(i2c_del_driver);
2051
2052/* ------------------------------------------------------------------------- */
2053
2054struct i2c_cmd_arg {
2055 unsigned cmd;
2056 void *arg;
2057};
2058
2059static int i2c_cmd(struct device *dev, void *_arg)
2060{
2061 struct i2c_client *client = i2c_verify_client(dev);
2062 struct i2c_cmd_arg *arg = _arg;
2063 struct i2c_driver *driver;
2064
2065 if (!client || !client->dev.driver)
2066 return 0;
2067
2068 driver = to_i2c_driver(client->dev.driver);
2069 if (driver->command)
2070 driver->command(client, arg->cmd, arg->arg);
2071 return 0;
2072}
2073
2074void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2075{
2076 struct i2c_cmd_arg cmd_arg;
2077
2078 cmd_arg.cmd = cmd;
2079 cmd_arg.arg = arg;
2080 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2081}
2082EXPORT_SYMBOL(i2c_clients_command);
2083
2084static int __init i2c_init(void)
2085{
2086 int retval;
2087
2088 retval = of_alias_get_highest_id("i2c");
2089
2090 down_write(&__i2c_board_lock);
2091 if (retval >= __i2c_first_dynamic_bus_num)
2092 __i2c_first_dynamic_bus_num = retval + 1;
2093 up_write(&__i2c_board_lock);
2094
2095 retval = bus_register(&i2c_bus_type);
2096 if (retval)
2097 return retval;
2098
2099 is_registered = true;
2100
2101 i2c_debugfs_root = debugfs_create_dir("i2c", NULL);
2102
2103 retval = i2c_add_driver(&dummy_driver);
2104 if (retval)
2105 goto class_err;
2106
2107 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2108 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2109 if (IS_ENABLED(CONFIG_ACPI))
2110 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2111
2112 return 0;
2113
2114class_err:
2115 is_registered = false;
2116 bus_unregister(&i2c_bus_type);
2117 return retval;
2118}
2119
2120static void __exit i2c_exit(void)
2121{
2122 if (IS_ENABLED(CONFIG_ACPI))
2123 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2124 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2125 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2126 i2c_del_driver(&dummy_driver);
2127 debugfs_remove_recursive(i2c_debugfs_root);
2128 bus_unregister(&i2c_bus_type);
2129 tracepoint_synchronize_unregister();
2130}
2131
2132/* We must initialize early, because some subsystems register i2c drivers
2133 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2134 */
2135postcore_initcall(i2c_init);
2136module_exit(i2c_exit);
2137
2138/* ----------------------------------------------------
2139 * the functional interface to the i2c busses.
2140 * ----------------------------------------------------
2141 */
2142
2143/* Check if val is exceeding the quirk IFF quirk is non 0 */
2144#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2145
2146static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2147{
2148 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2149 err_msg, msg->addr, msg->len,
2150 str_read_write(msg->flags & I2C_M_RD));
2151 return -EOPNOTSUPP;
2152}
2153
2154static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2155{
2156 const struct i2c_adapter_quirks *q = adap->quirks;
2157 int max_num = q->max_num_msgs, i;
2158 bool do_len_check = true;
2159
2160 if (q->flags & I2C_AQ_COMB) {
2161 max_num = 2;
2162
2163 /* special checks for combined messages */
2164 if (num == 2) {
2165 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2166 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2167
2168 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2169 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2170
2171 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2172 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2173
2174 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2175 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2176
2177 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2178 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2179
2180 do_len_check = false;
2181 }
2182 }
2183
2184 if (i2c_quirk_exceeded(num, max_num))
2185 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2186
2187 for (i = 0; i < num; i++) {
2188 u16 len = msgs[i].len;
2189
2190 if (msgs[i].flags & I2C_M_RD) {
2191 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2192 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2193
2194 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2195 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2196 } else {
2197 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2198 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2199
2200 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2201 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2202 }
2203 }
2204
2205 return 0;
2206}
2207
2208/**
2209 * __i2c_transfer - unlocked flavor of i2c_transfer
2210 * @adap: Handle to I2C bus
2211 * @msgs: One or more messages to execute before STOP is issued to
2212 * terminate the operation; each message begins with a START.
2213 * @num: Number of messages to be executed.
2214 *
2215 * Returns negative errno, else the number of messages executed.
2216 *
2217 * Adapter lock must be held when calling this function. No debug logging
2218 * takes place.
2219 */
2220int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2221{
2222 unsigned long orig_jiffies;
2223 int ret, try;
2224
2225 if (!adap->algo->master_xfer) {
2226 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2227 return -EOPNOTSUPP;
2228 }
2229
2230 if (WARN_ON(!msgs || num < 1))
2231 return -EINVAL;
2232
2233 ret = __i2c_check_suspended(adap);
2234 if (ret)
2235 return ret;
2236
2237 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2238 return -EOPNOTSUPP;
2239
2240 /*
2241 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2242 * enabled. This is an efficient way of keeping the for-loop from
2243 * being executed when not needed.
2244 */
2245 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2246 int i;
2247 for (i = 0; i < num; i++)
2248 if (msgs[i].flags & I2C_M_RD)
2249 trace_i2c_read(adap, &msgs[i], i);
2250 else
2251 trace_i2c_write(adap, &msgs[i], i);
2252 }
2253
2254 /* Retry automatically on arbitration loss */
2255 orig_jiffies = jiffies;
2256 for (ret = 0, try = 0; try <= adap->retries; try++) {
2257 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2258 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2259 else
2260 ret = adap->algo->master_xfer(adap, msgs, num);
2261
2262 if (ret != -EAGAIN)
2263 break;
2264 if (time_after(jiffies, orig_jiffies + adap->timeout))
2265 break;
2266 }
2267
2268 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2269 int i;
2270 for (i = 0; i < ret; i++)
2271 if (msgs[i].flags & I2C_M_RD)
2272 trace_i2c_reply(adap, &msgs[i], i);
2273 trace_i2c_result(adap, num, ret);
2274 }
2275
2276 return ret;
2277}
2278EXPORT_SYMBOL(__i2c_transfer);
2279
2280/**
2281 * i2c_transfer - execute a single or combined I2C message
2282 * @adap: Handle to I2C bus
2283 * @msgs: One or more messages to execute before STOP is issued to
2284 * terminate the operation; each message begins with a START.
2285 * @num: Number of messages to be executed.
2286 *
2287 * Returns negative errno, else the number of messages executed.
2288 *
2289 * Note that there is no requirement that each message be sent to
2290 * the same slave address, although that is the most common model.
2291 */
2292int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2293{
2294 int ret;
2295
2296 /* REVISIT the fault reporting model here is weak:
2297 *
2298 * - When we get an error after receiving N bytes from a slave,
2299 * there is no way to report "N".
2300 *
2301 * - When we get a NAK after transmitting N bytes to a slave,
2302 * there is no way to report "N" ... or to let the master
2303 * continue executing the rest of this combined message, if
2304 * that's the appropriate response.
2305 *
2306 * - When for example "num" is two and we successfully complete
2307 * the first message but get an error part way through the
2308 * second, it's unclear whether that should be reported as
2309 * one (discarding status on the second message) or errno
2310 * (discarding status on the first one).
2311 */
2312 ret = __i2c_lock_bus_helper(adap);
2313 if (ret)
2314 return ret;
2315
2316 ret = __i2c_transfer(adap, msgs, num);
2317 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2318
2319 return ret;
2320}
2321EXPORT_SYMBOL(i2c_transfer);
2322
2323/**
2324 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2325 * to/from a buffer
2326 * @client: Handle to slave device
2327 * @buf: Where the data is stored
2328 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2329 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2330 *
2331 * Returns negative errno, or else the number of bytes transferred.
2332 */
2333int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2334 int count, u16 flags)
2335{
2336 int ret;
2337 struct i2c_msg msg = {
2338 .addr = client->addr,
2339 .flags = flags | (client->flags & I2C_M_TEN),
2340 .len = count,
2341 .buf = buf,
2342 };
2343
2344 ret = i2c_transfer(client->adapter, &msg, 1);
2345
2346 /*
2347 * If everything went ok (i.e. 1 msg transferred), return #bytes
2348 * transferred, else error code.
2349 */
2350 return (ret == 1) ? count : ret;
2351}
2352EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2353
2354/**
2355 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2356 * @client: The device to query
2357 * @id: The queried information
2358 *
2359 * Returns negative errno on error, zero on success.
2360 */
2361int i2c_get_device_id(const struct i2c_client *client,
2362 struct i2c_device_identity *id)
2363{
2364 struct i2c_adapter *adap = client->adapter;
2365 union i2c_smbus_data raw_id;
2366 int ret;
2367
2368 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2369 return -EOPNOTSUPP;
2370
2371 raw_id.block[0] = 3;
2372 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2373 I2C_SMBUS_READ, client->addr << 1,
2374 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2375 if (ret)
2376 return ret;
2377
2378 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2379 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2380 id->die_revision = raw_id.block[3] & 0x7;
2381 return 0;
2382}
2383EXPORT_SYMBOL_GPL(i2c_get_device_id);
2384
2385/**
2386 * i2c_client_get_device_id - get the driver match table entry of a device
2387 * @client: the device to query. The device must be bound to a driver
2388 *
2389 * Returns a pointer to the matching entry if found, NULL otherwise.
2390 */
2391const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2392{
2393 const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2394
2395 return i2c_match_id(drv->id_table, client);
2396}
2397EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2398
2399/* ----------------------------------------------------
2400 * the i2c address scanning function
2401 * Will not work for 10-bit addresses!
2402 * ----------------------------------------------------
2403 */
2404
2405/*
2406 * Legacy default probe function, mostly relevant for SMBus. The default
2407 * probe method is a quick write, but it is known to corrupt the 24RF08
2408 * EEPROMs due to a state machine bug, and could also irreversibly
2409 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2410 * we use a short byte read instead. Also, some bus drivers don't implement
2411 * quick write, so we fallback to a byte read in that case too.
2412 * On x86, there is another special case for FSC hardware monitoring chips,
2413 * which want regular byte reads (address 0x73.) Fortunately, these are the
2414 * only known chips using this I2C address on PC hardware.
2415 * Returns 1 if probe succeeded, 0 if not.
2416 */
2417static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2418{
2419 int err;
2420 union i2c_smbus_data dummy;
2421
2422#ifdef CONFIG_X86
2423 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2424 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2425 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2426 I2C_SMBUS_BYTE_DATA, &dummy);
2427 else
2428#endif
2429 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2430 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2431 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2432 I2C_SMBUS_QUICK, NULL);
2433 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2434 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2435 I2C_SMBUS_BYTE, &dummy);
2436 else {
2437 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2438 addr);
2439 err = -EOPNOTSUPP;
2440 }
2441
2442 return err >= 0;
2443}
2444
2445static int i2c_detect_address(struct i2c_client *temp_client,
2446 struct i2c_driver *driver)
2447{
2448 struct i2c_board_info info;
2449 struct i2c_adapter *adapter = temp_client->adapter;
2450 int addr = temp_client->addr;
2451 int err;
2452
2453 /* Make sure the address is valid */
2454 err = i2c_check_7bit_addr_validity_strict(addr);
2455 if (err) {
2456 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2457 addr);
2458 return err;
2459 }
2460
2461 /* Skip if already in use (7 bit, no need to encode flags) */
2462 if (i2c_check_addr_busy(adapter, addr))
2463 return 0;
2464
2465 /* Make sure there is something at this address */
2466 if (!i2c_default_probe(adapter, addr))
2467 return 0;
2468
2469 /* Finally call the custom detection function */
2470 memset(&info, 0, sizeof(struct i2c_board_info));
2471 info.addr = addr;
2472 err = driver->detect(temp_client, &info);
2473 if (err) {
2474 /* -ENODEV is returned if the detection fails. We catch it
2475 here as this isn't an error. */
2476 return err == -ENODEV ? 0 : err;
2477 }
2478
2479 /* Consistency check */
2480 if (info.type[0] == '\0') {
2481 dev_err(&adapter->dev,
2482 "%s detection function provided no name for 0x%x\n",
2483 driver->driver.name, addr);
2484 } else {
2485 struct i2c_client *client;
2486
2487 /* Detection succeeded, instantiate the device */
2488 if (adapter->class & I2C_CLASS_DEPRECATED)
2489 dev_warn(&adapter->dev,
2490 "This adapter will soon drop class based instantiation of devices. "
2491 "Please make sure client 0x%02x gets instantiated by other means. "
2492 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2493 info.addr);
2494
2495 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2496 info.type, info.addr);
2497 client = i2c_new_client_device(adapter, &info);
2498 if (!IS_ERR(client))
2499 list_add_tail(&client->detected, &driver->clients);
2500 else
2501 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2502 info.type, info.addr);
2503 }
2504 return 0;
2505}
2506
2507static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2508{
2509 const unsigned short *address_list;
2510 struct i2c_client *temp_client;
2511 int i, err = 0;
2512
2513 address_list = driver->address_list;
2514 if (!driver->detect || !address_list)
2515 return 0;
2516
2517 /* Warn that the adapter lost class based instantiation */
2518 if (adapter->class == I2C_CLASS_DEPRECATED) {
2519 dev_dbg(&adapter->dev,
2520 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2521 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2522 driver->driver.name);
2523 return 0;
2524 }
2525
2526 /* Stop here if the classes do not match */
2527 if (!(adapter->class & driver->class))
2528 return 0;
2529
2530 /* Set up a temporary client to help detect callback */
2531 temp_client = kzalloc_obj(*temp_client);
2532 if (!temp_client)
2533 return -ENOMEM;
2534
2535 temp_client->adapter = adapter;
2536
2537 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2538 dev_dbg(&adapter->dev,
2539 "found normal entry for adapter %d, addr 0x%02x\n",
2540 i2c_adapter_id(adapter), address_list[i]);
2541 temp_client->addr = address_list[i];
2542 err = i2c_detect_address(temp_client, driver);
2543 if (unlikely(err))
2544 break;
2545 }
2546
2547 kfree(temp_client);
2548
2549 return err;
2550}
2551
2552int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2553{
2554 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2555 I2C_SMBUS_QUICK, NULL) >= 0;
2556}
2557EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2558
2559struct i2c_client *
2560i2c_new_scanned_device(struct i2c_adapter *adap,
2561 struct i2c_board_info *info,
2562 unsigned short const *addr_list,
2563 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2564{
2565 int i;
2566
2567 if (!probe)
2568 probe = i2c_default_probe;
2569
2570 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2571 /* Check address validity */
2572 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2573 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2574 addr_list[i]);
2575 continue;
2576 }
2577
2578 /* Check address availability (7 bit, no need to encode flags) */
2579 if (i2c_check_addr_busy(adap, addr_list[i])) {
2580 dev_dbg(&adap->dev,
2581 "Address 0x%02x already in use, not probing\n",
2582 addr_list[i]);
2583 continue;
2584 }
2585
2586 /* Test address responsiveness */
2587 if (probe(adap, addr_list[i]))
2588 break;
2589 }
2590
2591 if (addr_list[i] == I2C_CLIENT_END) {
2592 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2593 return ERR_PTR(-ENODEV);
2594 }
2595
2596 info->addr = addr_list[i];
2597 return i2c_new_client_device(adap, info);
2598}
2599EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2600
2601struct i2c_adapter *i2c_get_adapter(int nr)
2602{
2603 struct i2c_adapter *adapter;
2604
2605 mutex_lock(&core_lock);
2606 adapter = idr_find(&i2c_adapter_idr, nr);
2607 if (!adapter)
2608 goto exit;
2609
2610 if (try_module_get(adapter->owner))
2611 get_device(&adapter->dev);
2612 else
2613 adapter = NULL;
2614
2615 exit:
2616 mutex_unlock(&core_lock);
2617 return adapter;
2618}
2619EXPORT_SYMBOL(i2c_get_adapter);
2620
2621void i2c_put_adapter(struct i2c_adapter *adap)
2622{
2623 if (!adap)
2624 return;
2625
2626 module_put(adap->owner);
2627 /* Should be last, otherwise we risk use-after-free with 'adap' */
2628 put_device(&adap->dev);
2629}
2630EXPORT_SYMBOL(i2c_put_adapter);
2631
2632/**
2633 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2634 * @msg: the message to be checked
2635 * @threshold: the minimum number of bytes for which using DMA makes sense.
2636 * Should at least be 1.
2637 *
2638 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2639 * Or a valid pointer to be used with DMA. After use, release it by
2640 * calling i2c_put_dma_safe_msg_buf().
2641 *
2642 * This function must only be called from process context!
2643 */
2644u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2645{
2646 /* also skip 0-length msgs for bogus thresholds of 0 */
2647 if (!threshold)
2648 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2649 msg->addr);
2650 if (msg->len < threshold || msg->len == 0)
2651 return NULL;
2652
2653 if (msg->flags & I2C_M_DMA_SAFE)
2654 return msg->buf;
2655
2656 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2657 msg->addr, msg->len);
2658
2659 if (msg->flags & I2C_M_RD)
2660 return kzalloc(msg->len, GFP_KERNEL);
2661 else
2662 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2663}
2664EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2665
2666/**
2667 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2668 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2669 * @msg: the message which the buffer corresponds to
2670 * @xferred: bool saying if the message was transferred
2671 */
2672void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2673{
2674 if (!buf || buf == msg->buf)
2675 return;
2676
2677 if (xferred && msg->flags & I2C_M_RD)
2678 memcpy(msg->buf, buf, msg->len);
2679
2680 kfree(buf);
2681}
2682EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2683
2684MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2685MODULE_DESCRIPTION("I2C-Bus main module");
2686MODULE_LICENSE("GPL");