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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/irqflags.h>
28#include <linux/jump_label.h>
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/mutex.h>
32#include <linux/of_device.h>
33#include <linux/of.h>
34#include <linux/of_irq.h>
35#include <linux/pinctrl/consumer.h>
36#include <linux/pm_domain.h>
37#include <linux/pm_runtime.h>
38#include <linux/pm_wakeirq.h>
39#include <linux/property.h>
40#include <linux/rwsem.h>
41#include <linux/slab.h>
42
43#include "i2c-core.h"
44
45#define CREATE_TRACE_POINTS
46#include <trace/events/i2c.h>
47
48#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
49#define I2C_ADDR_OFFSET_SLAVE 0x1000
50
51#define I2C_ADDR_7BITS_MAX 0x77
52#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
53
54#define I2C_ADDR_DEVICE_ID 0x7c
55
56/*
57 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
58 * deletion of detected devices are serialized
59 */
60static DEFINE_MUTEX(core_lock);
61static DEFINE_IDR(i2c_adapter_idr);
62
63static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
64
65static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
66static bool is_registered;
67
68int i2c_transfer_trace_reg(void)
69{
70 static_branch_inc(&i2c_trace_msg_key);
71 return 0;
72}
73
74void i2c_transfer_trace_unreg(void)
75{
76 static_branch_dec(&i2c_trace_msg_key);
77}
78
79const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
80 const struct i2c_client *client)
81{
82 if (!(id && client))
83 return NULL;
84
85 while (id->name[0]) {
86 if (strcmp(client->name, id->name) == 0)
87 return id;
88 id++;
89 }
90 return NULL;
91}
92EXPORT_SYMBOL_GPL(i2c_match_id);
93
94static int i2c_device_match(struct device *dev, struct device_driver *drv)
95{
96 struct i2c_client *client = i2c_verify_client(dev);
97 struct i2c_driver *driver;
98
99
100 /* Attempt an OF style match */
101 if (i2c_of_match_device(drv->of_match_table, client))
102 return 1;
103
104 /* Then ACPI style match */
105 if (acpi_driver_match_device(dev, drv))
106 return 1;
107
108 driver = to_i2c_driver(drv);
109
110 /* Finally an I2C match */
111 if (i2c_match_id(driver->id_table, client))
112 return 1;
113
114 return 0;
115}
116
117static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
118{
119 struct i2c_client *client = to_i2c_client(dev);
120 int rc;
121
122 rc = of_device_uevent_modalias(dev, env);
123 if (rc != -ENODEV)
124 return rc;
125
126 rc = acpi_device_uevent_modalias(dev, env);
127 if (rc != -ENODEV)
128 return rc;
129
130 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
131}
132
133/* i2c bus recovery routines */
134static int get_scl_gpio_value(struct i2c_adapter *adap)
135{
136 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
137}
138
139static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
140{
141 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
142}
143
144static int get_sda_gpio_value(struct i2c_adapter *adap)
145{
146 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
147}
148
149static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
150{
151 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
152}
153
154static int i2c_generic_bus_free(struct i2c_adapter *adap)
155{
156 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
157 int ret = -EOPNOTSUPP;
158
159 if (bri->get_bus_free)
160 ret = bri->get_bus_free(adap);
161 else if (bri->get_sda)
162 ret = bri->get_sda(adap);
163
164 if (ret < 0)
165 return ret;
166
167 return ret ? 0 : -EBUSY;
168}
169
170/*
171 * We are generating clock pulses. ndelay() determines durating of clk pulses.
172 * We will generate clock with rate 100 KHz and so duration of both clock levels
173 * is: delay in ns = (10^6 / 100) / 2
174 */
175#define RECOVERY_NDELAY 5000
176#define RECOVERY_CLK_CNT 9
177
178int i2c_generic_scl_recovery(struct i2c_adapter *adap)
179{
180 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
181 int i = 0, scl = 1, ret = 0;
182
183 if (bri->prepare_recovery)
184 bri->prepare_recovery(adap);
185 if (bri->pinctrl)
186 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
187
188 /*
189 * If we can set SDA, we will always create a STOP to ensure additional
190 * pulses will do no harm. This is achieved by letting SDA follow SCL
191 * half a cycle later. Check the 'incomplete_write_byte' fault injector
192 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
193 * here for simplicity.
194 */
195 bri->set_scl(adap, scl);
196 ndelay(RECOVERY_NDELAY);
197 if (bri->set_sda)
198 bri->set_sda(adap, scl);
199 ndelay(RECOVERY_NDELAY / 2);
200
201 /*
202 * By this time SCL is high, as we need to give 9 falling-rising edges
203 */
204 while (i++ < RECOVERY_CLK_CNT * 2) {
205 if (scl) {
206 /* SCL shouldn't be low here */
207 if (!bri->get_scl(adap)) {
208 dev_err(&adap->dev,
209 "SCL is stuck low, exit recovery\n");
210 ret = -EBUSY;
211 break;
212 }
213 }
214
215 scl = !scl;
216 bri->set_scl(adap, scl);
217 /* Creating STOP again, see above */
218 if (scl) {
219 /* Honour minimum tsu:sto */
220 ndelay(RECOVERY_NDELAY);
221 } else {
222 /* Honour minimum tf and thd:dat */
223 ndelay(RECOVERY_NDELAY / 2);
224 }
225 if (bri->set_sda)
226 bri->set_sda(adap, scl);
227 ndelay(RECOVERY_NDELAY / 2);
228
229 if (scl) {
230 ret = i2c_generic_bus_free(adap);
231 if (ret == 0)
232 break;
233 }
234 }
235
236 /* If we can't check bus status, assume recovery worked */
237 if (ret == -EOPNOTSUPP)
238 ret = 0;
239
240 if (bri->unprepare_recovery)
241 bri->unprepare_recovery(adap);
242 if (bri->pinctrl)
243 pinctrl_select_state(bri->pinctrl, bri->pins_default);
244
245 return ret;
246}
247EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
248
249int i2c_recover_bus(struct i2c_adapter *adap)
250{
251 if (!adap->bus_recovery_info)
252 return -EOPNOTSUPP;
253
254 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
255 return adap->bus_recovery_info->recover_bus(adap);
256}
257EXPORT_SYMBOL_GPL(i2c_recover_bus);
258
259static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
260{
261 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
262 struct device *dev = &adap->dev;
263 struct pinctrl *p = bri->pinctrl;
264
265 /*
266 * we can't change states without pinctrl, so remove the states if
267 * populated
268 */
269 if (!p) {
270 bri->pins_default = NULL;
271 bri->pins_gpio = NULL;
272 return;
273 }
274
275 if (!bri->pins_default) {
276 bri->pins_default = pinctrl_lookup_state(p,
277 PINCTRL_STATE_DEFAULT);
278 if (IS_ERR(bri->pins_default)) {
279 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
280 bri->pins_default = NULL;
281 }
282 }
283 if (!bri->pins_gpio) {
284 bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
285 if (IS_ERR(bri->pins_gpio))
286 bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
287
288 if (IS_ERR(bri->pins_gpio)) {
289 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
290 bri->pins_gpio = NULL;
291 }
292 }
293
294 /* for pinctrl state changes, we need all the information */
295 if (bri->pins_default && bri->pins_gpio) {
296 dev_info(dev, "using pinctrl states for GPIO recovery");
297 } else {
298 bri->pinctrl = NULL;
299 bri->pins_default = NULL;
300 bri->pins_gpio = NULL;
301 }
302}
303
304static int i2c_gpio_init_generic_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 gpio_desc *gpiod;
309 int ret = 0;
310
311 /*
312 * don't touch the recovery information if the driver is not using
313 * generic SCL recovery
314 */
315 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
316 return 0;
317
318 /*
319 * pins might be taken as GPIO, so we should inform pinctrl about
320 * this and move the state to GPIO
321 */
322 if (bri->pinctrl)
323 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
324
325 /*
326 * if there is incomplete or no recovery information, see if generic
327 * GPIO recovery is available
328 */
329 if (!bri->scl_gpiod) {
330 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
331 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
332 ret = -EPROBE_DEFER;
333 goto cleanup_pinctrl_state;
334 }
335 if (!IS_ERR(gpiod)) {
336 bri->scl_gpiod = gpiod;
337 bri->recover_bus = i2c_generic_scl_recovery;
338 dev_info(dev, "using generic GPIOs for recovery\n");
339 }
340 }
341
342 /* SDA GPIOD line is optional, so we care about DEFER only */
343 if (!bri->sda_gpiod) {
344 /*
345 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
346 * have no effect.
347 */
348 gpiod_direction_output(bri->scl_gpiod, 0);
349 udelay(10);
350 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
351
352 /* Wait a bit in case of a SDA glitch, and then release SCL. */
353 udelay(10);
354 gpiod_direction_output(bri->scl_gpiod, 1);
355
356 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
357 ret = -EPROBE_DEFER;
358 goto cleanup_pinctrl_state;
359 }
360 if (!IS_ERR(gpiod))
361 bri->sda_gpiod = gpiod;
362 }
363
364cleanup_pinctrl_state:
365 /* change the state of the pins back to their default state */
366 if (bri->pinctrl)
367 pinctrl_select_state(bri->pinctrl, bri->pins_default);
368
369 return ret;
370}
371
372static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
373{
374 i2c_gpio_init_pinctrl_recovery(adap);
375 return i2c_gpio_init_generic_recovery(adap);
376}
377
378static int i2c_init_recovery(struct i2c_adapter *adap)
379{
380 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
381 char *err_str;
382
383 if (!bri)
384 return 0;
385
386 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
387 return -EPROBE_DEFER;
388
389 if (!bri->recover_bus) {
390 err_str = "no recover_bus() found";
391 goto err;
392 }
393
394 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
395 bri->get_scl = get_scl_gpio_value;
396 bri->set_scl = set_scl_gpio_value;
397 if (bri->sda_gpiod) {
398 bri->get_sda = get_sda_gpio_value;
399 /* FIXME: add proper flag instead of '0' once available */
400 if (gpiod_get_direction(bri->sda_gpiod) == 0)
401 bri->set_sda = set_sda_gpio_value;
402 }
403 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
404 /* Generic SCL recovery */
405 if (!bri->set_scl || !bri->get_scl) {
406 err_str = "no {get|set}_scl() found";
407 goto err;
408 }
409 if (!bri->set_sda && !bri->get_sda) {
410 err_str = "either get_sda() or set_sda() needed";
411 goto err;
412 }
413 }
414
415 return 0;
416 err:
417 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
418 adap->bus_recovery_info = NULL;
419
420 return -EINVAL;
421}
422
423static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
424{
425 struct i2c_adapter *adap = client->adapter;
426 unsigned int irq;
427
428 if (!adap->host_notify_domain)
429 return -ENXIO;
430
431 if (client->flags & I2C_CLIENT_TEN)
432 return -EINVAL;
433
434 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
435
436 return irq > 0 ? irq : -ENXIO;
437}
438
439static int i2c_device_probe(struct device *dev)
440{
441 struct i2c_client *client = i2c_verify_client(dev);
442 struct i2c_driver *driver;
443 int status;
444
445 if (!client)
446 return 0;
447
448 client->irq = client->init_irq;
449
450 if (!client->irq) {
451 int irq = -ENOENT;
452
453 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
454 dev_dbg(dev, "Using Host Notify IRQ\n");
455 /* Keep adapter active when Host Notify is required */
456 pm_runtime_get_sync(&client->adapter->dev);
457 irq = i2c_smbus_host_notify_to_irq(client);
458 } else if (dev->of_node) {
459 irq = of_irq_get_byname(dev->of_node, "irq");
460 if (irq == -EINVAL || irq == -ENODATA)
461 irq = of_irq_get(dev->of_node, 0);
462 } else if (ACPI_COMPANION(dev)) {
463 irq = i2c_acpi_get_irq(client);
464 }
465 if (irq == -EPROBE_DEFER) {
466 status = irq;
467 goto put_sync_adapter;
468 }
469
470 if (irq < 0)
471 irq = 0;
472
473 client->irq = irq;
474 }
475
476 driver = to_i2c_driver(dev->driver);
477
478 /*
479 * An I2C ID table is not mandatory, if and only if, a suitable OF
480 * or ACPI ID table is supplied for the probing device.
481 */
482 if (!driver->id_table &&
483 !acpi_driver_match_device(dev, dev->driver) &&
484 !i2c_of_match_device(dev->driver->of_match_table, client)) {
485 status = -ENODEV;
486 goto put_sync_adapter;
487 }
488
489 if (client->flags & I2C_CLIENT_WAKE) {
490 int wakeirq;
491
492 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
493 if (wakeirq == -EPROBE_DEFER) {
494 status = wakeirq;
495 goto put_sync_adapter;
496 }
497
498 device_init_wakeup(&client->dev, true);
499
500 if (wakeirq > 0 && wakeirq != client->irq)
501 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
502 else if (client->irq > 0)
503 status = dev_pm_set_wake_irq(dev, client->irq);
504 else
505 status = 0;
506
507 if (status)
508 dev_warn(&client->dev, "failed to set up wakeup irq\n");
509 }
510
511 dev_dbg(dev, "probe\n");
512
513 status = of_clk_set_defaults(dev->of_node, false);
514 if (status < 0)
515 goto err_clear_wakeup_irq;
516
517 status = dev_pm_domain_attach(&client->dev, true);
518 if (status)
519 goto err_clear_wakeup_irq;
520
521 /*
522 * When there are no more users of probe(),
523 * rename probe_new to probe.
524 */
525 if (driver->probe_new)
526 status = driver->probe_new(client);
527 else if (driver->probe)
528 status = driver->probe(client,
529 i2c_match_id(driver->id_table, client));
530 else
531 status = -EINVAL;
532
533 if (status)
534 goto err_detach_pm_domain;
535
536 return 0;
537
538err_detach_pm_domain:
539 dev_pm_domain_detach(&client->dev, true);
540err_clear_wakeup_irq:
541 dev_pm_clear_wake_irq(&client->dev);
542 device_init_wakeup(&client->dev, false);
543put_sync_adapter:
544 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
545 pm_runtime_put_sync(&client->adapter->dev);
546
547 return status;
548}
549
550static int i2c_device_remove(struct device *dev)
551{
552 struct i2c_client *client = i2c_verify_client(dev);
553 struct i2c_driver *driver;
554 int status = 0;
555
556 if (!client || !dev->driver)
557 return 0;
558
559 driver = to_i2c_driver(dev->driver);
560 if (driver->remove) {
561 dev_dbg(dev, "remove\n");
562 status = driver->remove(client);
563 }
564
565 dev_pm_domain_detach(&client->dev, true);
566
567 dev_pm_clear_wake_irq(&client->dev);
568 device_init_wakeup(&client->dev, false);
569
570 client->irq = 0;
571 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
572 pm_runtime_put(&client->adapter->dev);
573
574 return status;
575}
576
577static void i2c_device_shutdown(struct device *dev)
578{
579 struct i2c_client *client = i2c_verify_client(dev);
580 struct i2c_driver *driver;
581
582 if (!client || !dev->driver)
583 return;
584 driver = to_i2c_driver(dev->driver);
585 if (driver->shutdown)
586 driver->shutdown(client);
587}
588
589static void i2c_client_dev_release(struct device *dev)
590{
591 kfree(to_i2c_client(dev));
592}
593
594static ssize_t
595name_show(struct device *dev, struct device_attribute *attr, char *buf)
596{
597 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
598 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
599}
600static DEVICE_ATTR_RO(name);
601
602static ssize_t
603modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
604{
605 struct i2c_client *client = to_i2c_client(dev);
606 int len;
607
608 len = of_device_modalias(dev, buf, PAGE_SIZE);
609 if (len != -ENODEV)
610 return len;
611
612 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
613 if (len != -ENODEV)
614 return len;
615
616 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
617}
618static DEVICE_ATTR_RO(modalias);
619
620static struct attribute *i2c_dev_attrs[] = {
621 &dev_attr_name.attr,
622 /* modalias helps coldplug: modprobe $(cat .../modalias) */
623 &dev_attr_modalias.attr,
624 NULL
625};
626ATTRIBUTE_GROUPS(i2c_dev);
627
628struct bus_type i2c_bus_type = {
629 .name = "i2c",
630 .match = i2c_device_match,
631 .probe = i2c_device_probe,
632 .remove = i2c_device_remove,
633 .shutdown = i2c_device_shutdown,
634};
635EXPORT_SYMBOL_GPL(i2c_bus_type);
636
637struct device_type i2c_client_type = {
638 .groups = i2c_dev_groups,
639 .uevent = i2c_device_uevent,
640 .release = i2c_client_dev_release,
641};
642EXPORT_SYMBOL_GPL(i2c_client_type);
643
644
645/**
646 * i2c_verify_client - return parameter as i2c_client, or NULL
647 * @dev: device, probably from some driver model iterator
648 *
649 * When traversing the driver model tree, perhaps using driver model
650 * iterators like @device_for_each_child(), you can't assume very much
651 * about the nodes you find. Use this function to avoid oopses caused
652 * by wrongly treating some non-I2C device as an i2c_client.
653 */
654struct i2c_client *i2c_verify_client(struct device *dev)
655{
656 return (dev->type == &i2c_client_type)
657 ? to_i2c_client(dev)
658 : NULL;
659}
660EXPORT_SYMBOL(i2c_verify_client);
661
662
663/* Return a unique address which takes the flags of the client into account */
664static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
665{
666 unsigned short addr = client->addr;
667
668 /* For some client flags, add an arbitrary offset to avoid collisions */
669 if (client->flags & I2C_CLIENT_TEN)
670 addr |= I2C_ADDR_OFFSET_TEN_BIT;
671
672 if (client->flags & I2C_CLIENT_SLAVE)
673 addr |= I2C_ADDR_OFFSET_SLAVE;
674
675 return addr;
676}
677
678/* This is a permissive address validity check, I2C address map constraints
679 * are purposely not enforced, except for the general call address. */
680static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
681{
682 if (flags & I2C_CLIENT_TEN) {
683 /* 10-bit address, all values are valid */
684 if (addr > 0x3ff)
685 return -EINVAL;
686 } else {
687 /* 7-bit address, reject the general call address */
688 if (addr == 0x00 || addr > 0x7f)
689 return -EINVAL;
690 }
691 return 0;
692}
693
694/* And this is a strict address validity check, used when probing. If a
695 * device uses a reserved address, then it shouldn't be probed. 7-bit
696 * addressing is assumed, 10-bit address devices are rare and should be
697 * explicitly enumerated. */
698int i2c_check_7bit_addr_validity_strict(unsigned short addr)
699{
700 /*
701 * Reserved addresses per I2C specification:
702 * 0x00 General call address / START byte
703 * 0x01 CBUS address
704 * 0x02 Reserved for different bus format
705 * 0x03 Reserved for future purposes
706 * 0x04-0x07 Hs-mode master code
707 * 0x78-0x7b 10-bit slave addressing
708 * 0x7c-0x7f Reserved for future purposes
709 */
710 if (addr < 0x08 || addr > 0x77)
711 return -EINVAL;
712 return 0;
713}
714
715static int __i2c_check_addr_busy(struct device *dev, void *addrp)
716{
717 struct i2c_client *client = i2c_verify_client(dev);
718 int addr = *(int *)addrp;
719
720 if (client && i2c_encode_flags_to_addr(client) == addr)
721 return -EBUSY;
722 return 0;
723}
724
725/* walk up mux tree */
726static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
727{
728 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
729 int result;
730
731 result = device_for_each_child(&adapter->dev, &addr,
732 __i2c_check_addr_busy);
733
734 if (!result && parent)
735 result = i2c_check_mux_parents(parent, addr);
736
737 return result;
738}
739
740/* recurse down mux tree */
741static int i2c_check_mux_children(struct device *dev, void *addrp)
742{
743 int result;
744
745 if (dev->type == &i2c_adapter_type)
746 result = device_for_each_child(dev, addrp,
747 i2c_check_mux_children);
748 else
749 result = __i2c_check_addr_busy(dev, addrp);
750
751 return result;
752}
753
754static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
755{
756 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
757 int result = 0;
758
759 if (parent)
760 result = i2c_check_mux_parents(parent, addr);
761
762 if (!result)
763 result = device_for_each_child(&adapter->dev, &addr,
764 i2c_check_mux_children);
765
766 return result;
767}
768
769/**
770 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
771 * @adapter: Target I2C bus segment
772 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
773 * locks only this branch in the adapter tree
774 */
775static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
776 unsigned int flags)
777{
778 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
779}
780
781/**
782 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
783 * @adapter: Target I2C bus segment
784 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
785 * trylocks only this branch in the adapter tree
786 */
787static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
788 unsigned int flags)
789{
790 return rt_mutex_trylock(&adapter->bus_lock);
791}
792
793/**
794 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
795 * @adapter: Target I2C bus segment
796 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
797 * unlocks only this branch in the adapter tree
798 */
799static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
800 unsigned int flags)
801{
802 rt_mutex_unlock(&adapter->bus_lock);
803}
804
805static void i2c_dev_set_name(struct i2c_adapter *adap,
806 struct i2c_client *client,
807 struct i2c_board_info const *info)
808{
809 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
810
811 if (info && info->dev_name) {
812 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
813 return;
814 }
815
816 if (adev) {
817 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
818 return;
819 }
820
821 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
822 i2c_encode_flags_to_addr(client));
823}
824
825int i2c_dev_irq_from_resources(const struct resource *resources,
826 unsigned int num_resources)
827{
828 struct irq_data *irqd;
829 int i;
830
831 for (i = 0; i < num_resources; i++) {
832 const struct resource *r = &resources[i];
833
834 if (resource_type(r) != IORESOURCE_IRQ)
835 continue;
836
837 if (r->flags & IORESOURCE_BITS) {
838 irqd = irq_get_irq_data(r->start);
839 if (!irqd)
840 break;
841
842 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
843 }
844
845 return r->start;
846 }
847
848 return 0;
849}
850
851/**
852 * i2c_new_client_device - instantiate an i2c device
853 * @adap: the adapter managing the device
854 * @info: describes one I2C device; bus_num is ignored
855 * Context: can sleep
856 *
857 * Create an i2c device. Binding is handled through driver model
858 * probe()/remove() methods. A driver may be bound to this device when we
859 * return from this function, or any later moment (e.g. maybe hotplugging will
860 * load the driver module). This call is not appropriate for use by mainboard
861 * initialization logic, which usually runs during an arch_initcall() long
862 * before any i2c_adapter could exist.
863 *
864 * This returns the new i2c client, which may be saved for later use with
865 * i2c_unregister_device(); or an ERR_PTR to describe the error.
866 */
867struct i2c_client *
868i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
869{
870 struct i2c_client *client;
871 int status;
872
873 client = kzalloc(sizeof *client, GFP_KERNEL);
874 if (!client)
875 return ERR_PTR(-ENOMEM);
876
877 client->adapter = adap;
878
879 client->dev.platform_data = info->platform_data;
880 client->flags = info->flags;
881 client->addr = info->addr;
882
883 client->init_irq = info->irq;
884 if (!client->init_irq)
885 client->init_irq = i2c_dev_irq_from_resources(info->resources,
886 info->num_resources);
887
888 strlcpy(client->name, info->type, sizeof(client->name));
889
890 status = i2c_check_addr_validity(client->addr, client->flags);
891 if (status) {
892 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
893 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
894 goto out_err_silent;
895 }
896
897 /* Check for address business */
898 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
899 if (status)
900 goto out_err;
901
902 client->dev.parent = &client->adapter->dev;
903 client->dev.bus = &i2c_bus_type;
904 client->dev.type = &i2c_client_type;
905 client->dev.of_node = of_node_get(info->of_node);
906 client->dev.fwnode = info->fwnode;
907
908 i2c_dev_set_name(adap, client, info);
909
910 if (info->properties) {
911 status = device_add_properties(&client->dev, info->properties);
912 if (status) {
913 dev_err(&adap->dev,
914 "Failed to add properties to client %s: %d\n",
915 client->name, status);
916 goto out_err_put_of_node;
917 }
918 }
919
920 status = device_register(&client->dev);
921 if (status)
922 goto out_free_props;
923
924 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
925 client->name, dev_name(&client->dev));
926
927 return client;
928
929out_free_props:
930 if (info->properties)
931 device_remove_properties(&client->dev);
932out_err_put_of_node:
933 of_node_put(info->of_node);
934out_err:
935 dev_err(&adap->dev,
936 "Failed to register i2c client %s at 0x%02x (%d)\n",
937 client->name, client->addr, status);
938out_err_silent:
939 kfree(client);
940 return ERR_PTR(status);
941}
942EXPORT_SYMBOL_GPL(i2c_new_client_device);
943
944/**
945 * i2c_unregister_device - reverse effect of i2c_new_*_device()
946 * @client: value returned from i2c_new_*_device()
947 * Context: can sleep
948 */
949void i2c_unregister_device(struct i2c_client *client)
950{
951 if (IS_ERR_OR_NULL(client))
952 return;
953
954 if (client->dev.of_node) {
955 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
956 of_node_put(client->dev.of_node);
957 }
958
959 if (ACPI_COMPANION(&client->dev))
960 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
961 device_unregister(&client->dev);
962}
963EXPORT_SYMBOL_GPL(i2c_unregister_device);
964
965
966static const struct i2c_device_id dummy_id[] = {
967 { "dummy", 0 },
968 { },
969};
970
971static int dummy_probe(struct i2c_client *client,
972 const struct i2c_device_id *id)
973{
974 return 0;
975}
976
977static int dummy_remove(struct i2c_client *client)
978{
979 return 0;
980}
981
982static struct i2c_driver dummy_driver = {
983 .driver.name = "dummy",
984 .probe = dummy_probe,
985 .remove = dummy_remove,
986 .id_table = dummy_id,
987};
988
989/**
990 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
991 * @adapter: the adapter managing the device
992 * @address: seven bit address to be used
993 * Context: can sleep
994 *
995 * This returns an I2C client bound to the "dummy" driver, intended for use
996 * with devices that consume multiple addresses. Examples of such chips
997 * include various EEPROMS (like 24c04 and 24c08 models).
998 *
999 * These dummy devices have two main uses. First, most I2C and SMBus calls
1000 * except i2c_transfer() need a client handle; the dummy will be that handle.
1001 * And second, this prevents the specified address from being bound to a
1002 * different driver.
1003 *
1004 * This returns the new i2c client, which should be saved for later use with
1005 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1006 */
1007struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1008{
1009 struct i2c_board_info info = {
1010 I2C_BOARD_INFO("dummy", address),
1011 };
1012
1013 return i2c_new_client_device(adapter, &info);
1014}
1015EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1016
1017struct i2c_dummy_devres {
1018 struct i2c_client *client;
1019};
1020
1021static void devm_i2c_release_dummy(struct device *dev, void *res)
1022{
1023 struct i2c_dummy_devres *this = res;
1024
1025 i2c_unregister_device(this->client);
1026}
1027
1028/**
1029 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1030 * @dev: device the managed resource is bound to
1031 * @adapter: the adapter managing the device
1032 * @address: seven bit address to be used
1033 * Context: can sleep
1034 *
1035 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1036 * new i2c client or an ERR_PTR in case of an error.
1037 */
1038struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1039 struct i2c_adapter *adapter,
1040 u16 address)
1041{
1042 struct i2c_dummy_devres *dr;
1043 struct i2c_client *client;
1044
1045 dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
1046 if (!dr)
1047 return ERR_PTR(-ENOMEM);
1048
1049 client = i2c_new_dummy_device(adapter, address);
1050 if (IS_ERR(client)) {
1051 devres_free(dr);
1052 } else {
1053 dr->client = client;
1054 devres_add(dev, dr);
1055 }
1056
1057 return client;
1058}
1059EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1060
1061/**
1062 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1063 * and create the associated device
1064 * @client: Handle to the primary client
1065 * @name: Handle to specify which secondary address to get
1066 * @default_addr: Used as a fallback if no secondary address was specified
1067 * Context: can sleep
1068 *
1069 * I2C clients can be composed of multiple I2C slaves bound together in a single
1070 * component. The I2C client driver then binds to the master I2C slave and needs
1071 * to create I2C dummy clients to communicate with all the other slaves.
1072 *
1073 * This function creates and returns an I2C dummy client whose I2C address is
1074 * retrieved from the platform firmware based on the given slave name. If no
1075 * address is specified by the firmware default_addr is used.
1076 *
1077 * On DT-based platforms the address is retrieved from the "reg" property entry
1078 * cell whose "reg-names" value matches the slave name.
1079 *
1080 * This returns the new i2c client, which should be saved for later use with
1081 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1082 */
1083struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1084 const char *name,
1085 u16 default_addr)
1086{
1087 struct device_node *np = client->dev.of_node;
1088 u32 addr = default_addr;
1089 int i;
1090
1091 if (np) {
1092 i = of_property_match_string(np, "reg-names", name);
1093 if (i >= 0)
1094 of_property_read_u32_index(np, "reg", i, &addr);
1095 }
1096
1097 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1098 return i2c_new_dummy_device(client->adapter, addr);
1099}
1100EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1101
1102/* ------------------------------------------------------------------------- */
1103
1104/* I2C bus adapters -- one roots each I2C or SMBUS segment */
1105
1106static void i2c_adapter_dev_release(struct device *dev)
1107{
1108 struct i2c_adapter *adap = to_i2c_adapter(dev);
1109 complete(&adap->dev_released);
1110}
1111
1112unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1113{
1114 unsigned int depth = 0;
1115
1116 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1117 depth++;
1118
1119 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1120 "adapter depth exceeds lockdep subclass limit\n");
1121
1122 return depth;
1123}
1124EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1125
1126/*
1127 * Let users instantiate I2C devices through sysfs. This can be used when
1128 * platform initialization code doesn't contain the proper data for
1129 * whatever reason. Also useful for drivers that do device detection and
1130 * detection fails, either because the device uses an unexpected address,
1131 * or this is a compatible device with different ID register values.
1132 *
1133 * Parameter checking may look overzealous, but we really don't want
1134 * the user to provide incorrect parameters.
1135 */
1136static ssize_t
1137new_device_store(struct device *dev, struct device_attribute *attr,
1138 const char *buf, size_t count)
1139{
1140 struct i2c_adapter *adap = to_i2c_adapter(dev);
1141 struct i2c_board_info info;
1142 struct i2c_client *client;
1143 char *blank, end;
1144 int res;
1145
1146 memset(&info, 0, sizeof(struct i2c_board_info));
1147
1148 blank = strchr(buf, ' ');
1149 if (!blank) {
1150 dev_err(dev, "%s: Missing parameters\n", "new_device");
1151 return -EINVAL;
1152 }
1153 if (blank - buf > I2C_NAME_SIZE - 1) {
1154 dev_err(dev, "%s: Invalid device name\n", "new_device");
1155 return -EINVAL;
1156 }
1157 memcpy(info.type, buf, blank - buf);
1158
1159 /* Parse remaining parameters, reject extra parameters */
1160 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1161 if (res < 1) {
1162 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1163 return -EINVAL;
1164 }
1165 if (res > 1 && end != '\n') {
1166 dev_err(dev, "%s: Extra parameters\n", "new_device");
1167 return -EINVAL;
1168 }
1169
1170 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1171 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1172 info.flags |= I2C_CLIENT_TEN;
1173 }
1174
1175 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1176 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1177 info.flags |= I2C_CLIENT_SLAVE;
1178 }
1179
1180 client = i2c_new_client_device(adap, &info);
1181 if (IS_ERR(client))
1182 return PTR_ERR(client);
1183
1184 /* Keep track of the added device */
1185 mutex_lock(&adap->userspace_clients_lock);
1186 list_add_tail(&client->detected, &adap->userspace_clients);
1187 mutex_unlock(&adap->userspace_clients_lock);
1188 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1189 info.type, info.addr);
1190
1191 return count;
1192}
1193static DEVICE_ATTR_WO(new_device);
1194
1195/*
1196 * And of course let the users delete the devices they instantiated, if
1197 * they got it wrong. This interface can only be used to delete devices
1198 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1199 * don't delete devices to which some kernel code still has references.
1200 *
1201 * Parameter checking may look overzealous, but we really don't want
1202 * the user to delete the wrong device.
1203 */
1204static ssize_t
1205delete_device_store(struct device *dev, struct device_attribute *attr,
1206 const char *buf, size_t count)
1207{
1208 struct i2c_adapter *adap = to_i2c_adapter(dev);
1209 struct i2c_client *client, *next;
1210 unsigned short addr;
1211 char end;
1212 int res;
1213
1214 /* Parse parameters, reject extra parameters */
1215 res = sscanf(buf, "%hi%c", &addr, &end);
1216 if (res < 1) {
1217 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1218 return -EINVAL;
1219 }
1220 if (res > 1 && end != '\n') {
1221 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1222 return -EINVAL;
1223 }
1224
1225 /* Make sure the device was added through sysfs */
1226 res = -ENOENT;
1227 mutex_lock_nested(&adap->userspace_clients_lock,
1228 i2c_adapter_depth(adap));
1229 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1230 detected) {
1231 if (i2c_encode_flags_to_addr(client) == addr) {
1232 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1233 "delete_device", client->name, client->addr);
1234
1235 list_del(&client->detected);
1236 i2c_unregister_device(client);
1237 res = count;
1238 break;
1239 }
1240 }
1241 mutex_unlock(&adap->userspace_clients_lock);
1242
1243 if (res < 0)
1244 dev_err(dev, "%s: Can't find device in list\n",
1245 "delete_device");
1246 return res;
1247}
1248static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1249 delete_device_store);
1250
1251static struct attribute *i2c_adapter_attrs[] = {
1252 &dev_attr_name.attr,
1253 &dev_attr_new_device.attr,
1254 &dev_attr_delete_device.attr,
1255 NULL
1256};
1257ATTRIBUTE_GROUPS(i2c_adapter);
1258
1259struct device_type i2c_adapter_type = {
1260 .groups = i2c_adapter_groups,
1261 .release = i2c_adapter_dev_release,
1262};
1263EXPORT_SYMBOL_GPL(i2c_adapter_type);
1264
1265/**
1266 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1267 * @dev: device, probably from some driver model iterator
1268 *
1269 * When traversing the driver model tree, perhaps using driver model
1270 * iterators like @device_for_each_child(), you can't assume very much
1271 * about the nodes you find. Use this function to avoid oopses caused
1272 * by wrongly treating some non-I2C device as an i2c_adapter.
1273 */
1274struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1275{
1276 return (dev->type == &i2c_adapter_type)
1277 ? to_i2c_adapter(dev)
1278 : NULL;
1279}
1280EXPORT_SYMBOL(i2c_verify_adapter);
1281
1282#ifdef CONFIG_I2C_COMPAT
1283static struct class_compat *i2c_adapter_compat_class;
1284#endif
1285
1286static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1287{
1288 struct i2c_devinfo *devinfo;
1289
1290 down_read(&__i2c_board_lock);
1291 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1292 if (devinfo->busnum == adapter->nr &&
1293 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1294 dev_err(&adapter->dev,
1295 "Can't create device at 0x%02x\n",
1296 devinfo->board_info.addr);
1297 }
1298 up_read(&__i2c_board_lock);
1299}
1300
1301static int i2c_do_add_adapter(struct i2c_driver *driver,
1302 struct i2c_adapter *adap)
1303{
1304 /* Detect supported devices on that bus, and instantiate them */
1305 i2c_detect(adap, driver);
1306
1307 return 0;
1308}
1309
1310static int __process_new_adapter(struct device_driver *d, void *data)
1311{
1312 return i2c_do_add_adapter(to_i2c_driver(d), data);
1313}
1314
1315static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1316 .lock_bus = i2c_adapter_lock_bus,
1317 .trylock_bus = i2c_adapter_trylock_bus,
1318 .unlock_bus = i2c_adapter_unlock_bus,
1319};
1320
1321static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1322{
1323 struct irq_domain *domain = adap->host_notify_domain;
1324 irq_hw_number_t hwirq;
1325
1326 if (!domain)
1327 return;
1328
1329 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1330 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1331
1332 irq_domain_remove(domain);
1333 adap->host_notify_domain = NULL;
1334}
1335
1336static int i2c_host_notify_irq_map(struct irq_domain *h,
1337 unsigned int virq,
1338 irq_hw_number_t hw_irq_num)
1339{
1340 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1341
1342 return 0;
1343}
1344
1345static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1346 .map = i2c_host_notify_irq_map,
1347};
1348
1349static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1350{
1351 struct irq_domain *domain;
1352
1353 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1354 return 0;
1355
1356 domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1357 I2C_ADDR_7BITS_COUNT,
1358 &i2c_host_notify_irq_ops, adap);
1359 if (!domain)
1360 return -ENOMEM;
1361
1362 adap->host_notify_domain = domain;
1363
1364 return 0;
1365}
1366
1367/**
1368 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1369 * I2C client.
1370 * @adap: the adapter
1371 * @addr: the I2C address of the notifying device
1372 * Context: can't sleep
1373 *
1374 * Helper function to be called from an I2C bus driver's interrupt
1375 * handler. It will schedule the Host Notify IRQ.
1376 */
1377int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1378{
1379 int irq;
1380
1381 if (!adap)
1382 return -EINVAL;
1383
1384 irq = irq_find_mapping(adap->host_notify_domain, addr);
1385 if (irq <= 0)
1386 return -ENXIO;
1387
1388 generic_handle_irq(irq);
1389
1390 return 0;
1391}
1392EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1393
1394static int i2c_register_adapter(struct i2c_adapter *adap)
1395{
1396 int res = -EINVAL;
1397
1398 /* Can't register until after driver model init */
1399 if (WARN_ON(!is_registered)) {
1400 res = -EAGAIN;
1401 goto out_list;
1402 }
1403
1404 /* Sanity checks */
1405 if (WARN(!adap->name[0], "i2c adapter has no name"))
1406 goto out_list;
1407
1408 if (!adap->algo) {
1409 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1410 goto out_list;
1411 }
1412
1413 if (!adap->lock_ops)
1414 adap->lock_ops = &i2c_adapter_lock_ops;
1415
1416 adap->locked_flags = 0;
1417 rt_mutex_init(&adap->bus_lock);
1418 rt_mutex_init(&adap->mux_lock);
1419 mutex_init(&adap->userspace_clients_lock);
1420 INIT_LIST_HEAD(&adap->userspace_clients);
1421
1422 /* Set default timeout to 1 second if not already set */
1423 if (adap->timeout == 0)
1424 adap->timeout = HZ;
1425
1426 /* register soft irqs for Host Notify */
1427 res = i2c_setup_host_notify_irq_domain(adap);
1428 if (res) {
1429 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1430 adap->name, res);
1431 goto out_list;
1432 }
1433
1434 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1435 adap->dev.bus = &i2c_bus_type;
1436 adap->dev.type = &i2c_adapter_type;
1437 res = device_register(&adap->dev);
1438 if (res) {
1439 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1440 goto out_list;
1441 }
1442
1443 res = of_i2c_setup_smbus_alert(adap);
1444 if (res)
1445 goto out_reg;
1446
1447 pm_runtime_no_callbacks(&adap->dev);
1448 pm_suspend_ignore_children(&adap->dev, true);
1449 pm_runtime_enable(&adap->dev);
1450
1451 res = i2c_init_recovery(adap);
1452 if (res == -EPROBE_DEFER)
1453 goto out_reg;
1454
1455 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1456
1457#ifdef CONFIG_I2C_COMPAT
1458 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1459 adap->dev.parent);
1460 if (res)
1461 dev_warn(&adap->dev,
1462 "Failed to create compatibility class link\n");
1463#endif
1464
1465 /* create pre-declared device nodes */
1466 of_i2c_register_devices(adap);
1467 i2c_acpi_install_space_handler(adap);
1468 i2c_acpi_register_devices(adap);
1469
1470 if (adap->nr < __i2c_first_dynamic_bus_num)
1471 i2c_scan_static_board_info(adap);
1472
1473 /* Notify drivers */
1474 mutex_lock(&core_lock);
1475 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1476 mutex_unlock(&core_lock);
1477
1478 return 0;
1479
1480out_reg:
1481 init_completion(&adap->dev_released);
1482 device_unregister(&adap->dev);
1483 wait_for_completion(&adap->dev_released);
1484out_list:
1485 mutex_lock(&core_lock);
1486 idr_remove(&i2c_adapter_idr, adap->nr);
1487 mutex_unlock(&core_lock);
1488 return res;
1489}
1490
1491/**
1492 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1493 * @adap: the adapter to register (with adap->nr initialized)
1494 * Context: can sleep
1495 *
1496 * See i2c_add_numbered_adapter() for details.
1497 */
1498static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1499{
1500 int id;
1501
1502 mutex_lock(&core_lock);
1503 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1504 mutex_unlock(&core_lock);
1505 if (WARN(id < 0, "couldn't get idr"))
1506 return id == -ENOSPC ? -EBUSY : id;
1507
1508 return i2c_register_adapter(adap);
1509}
1510
1511/**
1512 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1513 * @adapter: the adapter to add
1514 * Context: can sleep
1515 *
1516 * This routine is used to declare an I2C adapter when its bus number
1517 * doesn't matter or when its bus number is specified by an dt alias.
1518 * Examples of bases when the bus number doesn't matter: I2C adapters
1519 * dynamically added by USB links or PCI plugin cards.
1520 *
1521 * When this returns zero, a new bus number was allocated and stored
1522 * in adap->nr, and the specified adapter became available for clients.
1523 * Otherwise, a negative errno value is returned.
1524 */
1525int i2c_add_adapter(struct i2c_adapter *adapter)
1526{
1527 struct device *dev = &adapter->dev;
1528 int id;
1529
1530 if (dev->of_node) {
1531 id = of_alias_get_id(dev->of_node, "i2c");
1532 if (id >= 0) {
1533 adapter->nr = id;
1534 return __i2c_add_numbered_adapter(adapter);
1535 }
1536 }
1537
1538 mutex_lock(&core_lock);
1539 id = idr_alloc(&i2c_adapter_idr, adapter,
1540 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1541 mutex_unlock(&core_lock);
1542 if (WARN(id < 0, "couldn't get idr"))
1543 return id;
1544
1545 adapter->nr = id;
1546
1547 return i2c_register_adapter(adapter);
1548}
1549EXPORT_SYMBOL(i2c_add_adapter);
1550
1551/**
1552 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1553 * @adap: the adapter to register (with adap->nr initialized)
1554 * Context: can sleep
1555 *
1556 * This routine is used to declare an I2C adapter when its bus number
1557 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1558 * or otherwise built in to the system's mainboard, and where i2c_board_info
1559 * is used to properly configure I2C devices.
1560 *
1561 * If the requested bus number is set to -1, then this function will behave
1562 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1563 *
1564 * If no devices have pre-been declared for this bus, then be sure to
1565 * register the adapter before any dynamically allocated ones. Otherwise
1566 * the required bus ID may not be available.
1567 *
1568 * When this returns zero, the specified adapter became available for
1569 * clients using the bus number provided in adap->nr. Also, the table
1570 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1571 * and the appropriate driver model device nodes are created. Otherwise, a
1572 * negative errno value is returned.
1573 */
1574int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1575{
1576 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1577 return i2c_add_adapter(adap);
1578
1579 return __i2c_add_numbered_adapter(adap);
1580}
1581EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1582
1583static void i2c_do_del_adapter(struct i2c_driver *driver,
1584 struct i2c_adapter *adapter)
1585{
1586 struct i2c_client *client, *_n;
1587
1588 /* Remove the devices we created ourselves as the result of hardware
1589 * probing (using a driver's detect method) */
1590 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1591 if (client->adapter == adapter) {
1592 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1593 client->name, client->addr);
1594 list_del(&client->detected);
1595 i2c_unregister_device(client);
1596 }
1597 }
1598}
1599
1600static int __unregister_client(struct device *dev, void *dummy)
1601{
1602 struct i2c_client *client = i2c_verify_client(dev);
1603 if (client && strcmp(client->name, "dummy"))
1604 i2c_unregister_device(client);
1605 return 0;
1606}
1607
1608static int __unregister_dummy(struct device *dev, void *dummy)
1609{
1610 struct i2c_client *client = i2c_verify_client(dev);
1611 i2c_unregister_device(client);
1612 return 0;
1613}
1614
1615static int __process_removed_adapter(struct device_driver *d, void *data)
1616{
1617 i2c_do_del_adapter(to_i2c_driver(d), data);
1618 return 0;
1619}
1620
1621/**
1622 * i2c_del_adapter - unregister I2C adapter
1623 * @adap: the adapter being unregistered
1624 * Context: can sleep
1625 *
1626 * This unregisters an I2C adapter which was previously registered
1627 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1628 */
1629void i2c_del_adapter(struct i2c_adapter *adap)
1630{
1631 struct i2c_adapter *found;
1632 struct i2c_client *client, *next;
1633
1634 /* First make sure that this adapter was ever added */
1635 mutex_lock(&core_lock);
1636 found = idr_find(&i2c_adapter_idr, adap->nr);
1637 mutex_unlock(&core_lock);
1638 if (found != adap) {
1639 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1640 return;
1641 }
1642
1643 i2c_acpi_remove_space_handler(adap);
1644 /* Tell drivers about this removal */
1645 mutex_lock(&core_lock);
1646 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1647 __process_removed_adapter);
1648 mutex_unlock(&core_lock);
1649
1650 /* Remove devices instantiated from sysfs */
1651 mutex_lock_nested(&adap->userspace_clients_lock,
1652 i2c_adapter_depth(adap));
1653 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1654 detected) {
1655 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1656 client->addr);
1657 list_del(&client->detected);
1658 i2c_unregister_device(client);
1659 }
1660 mutex_unlock(&adap->userspace_clients_lock);
1661
1662 /* Detach any active clients. This can't fail, thus we do not
1663 * check the returned value. This is a two-pass process, because
1664 * we can't remove the dummy devices during the first pass: they
1665 * could have been instantiated by real devices wishing to clean
1666 * them up properly, so we give them a chance to do that first. */
1667 device_for_each_child(&adap->dev, NULL, __unregister_client);
1668 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1669
1670#ifdef CONFIG_I2C_COMPAT
1671 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1672 adap->dev.parent);
1673#endif
1674
1675 /* device name is gone after device_unregister */
1676 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1677
1678 pm_runtime_disable(&adap->dev);
1679
1680 i2c_host_notify_irq_teardown(adap);
1681
1682 /* wait until all references to the device are gone
1683 *
1684 * FIXME: This is old code and should ideally be replaced by an
1685 * alternative which results in decoupling the lifetime of the struct
1686 * device from the i2c_adapter, like spi or netdev do. Any solution
1687 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1688 */
1689 init_completion(&adap->dev_released);
1690 device_unregister(&adap->dev);
1691 wait_for_completion(&adap->dev_released);
1692
1693 /* free bus id */
1694 mutex_lock(&core_lock);
1695 idr_remove(&i2c_adapter_idr, adap->nr);
1696 mutex_unlock(&core_lock);
1697
1698 /* Clear the device structure in case this adapter is ever going to be
1699 added again */
1700 memset(&adap->dev, 0, sizeof(adap->dev));
1701}
1702EXPORT_SYMBOL(i2c_del_adapter);
1703
1704static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1705 u32 def_val, bool use_def)
1706{
1707 int ret;
1708
1709 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1710 if (ret && use_def)
1711 *cur_val_p = def_val;
1712
1713 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1714}
1715
1716/**
1717 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1718 * @dev: The device to scan for I2C timing properties
1719 * @t: the i2c_timings struct to be filled with values
1720 * @use_defaults: bool to use sane defaults derived from the I2C specification
1721 * when properties are not found, otherwise don't update
1722 *
1723 * Scan the device for the generic I2C properties describing timing parameters
1724 * for the signal and fill the given struct with the results. If a property was
1725 * not found and use_defaults was true, then maximum timings are assumed which
1726 * are derived from the I2C specification. If use_defaults is not used, the
1727 * results will be as before, so drivers can apply their own defaults before
1728 * calling this helper. The latter is mainly intended for avoiding regressions
1729 * of existing drivers which want to switch to this function. New drivers
1730 * almost always should use the defaults.
1731 */
1732void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1733{
1734 bool u = use_defaults;
1735 u32 d;
1736
1737 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1738 I2C_MAX_STANDARD_MODE_FREQ, u);
1739
1740 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1741 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1742 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1743
1744 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1745 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1746
1747 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1748 &t->scl_int_delay_ns, 0, u);
1749 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1750 t->scl_fall_ns, u);
1751 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1752 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1753 &t->digital_filter_width_ns, 0, u);
1754 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1755 &t->analog_filter_cutoff_freq_hz, 0, u);
1756}
1757EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1758
1759/* ------------------------------------------------------------------------- */
1760
1761int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1762{
1763 int res;
1764
1765 mutex_lock(&core_lock);
1766 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1767 mutex_unlock(&core_lock);
1768
1769 return res;
1770}
1771EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1772
1773static int __process_new_driver(struct device *dev, void *data)
1774{
1775 if (dev->type != &i2c_adapter_type)
1776 return 0;
1777 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1778}
1779
1780/*
1781 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1782 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1783 */
1784
1785int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1786{
1787 int res;
1788
1789 /* Can't register until after driver model init */
1790 if (WARN_ON(!is_registered))
1791 return -EAGAIN;
1792
1793 /* add the driver to the list of i2c drivers in the driver core */
1794 driver->driver.owner = owner;
1795 driver->driver.bus = &i2c_bus_type;
1796 INIT_LIST_HEAD(&driver->clients);
1797
1798 /* When registration returns, the driver core
1799 * will have called probe() for all matching-but-unbound devices.
1800 */
1801 res = driver_register(&driver->driver);
1802 if (res)
1803 return res;
1804
1805 pr_debug("driver [%s] registered\n", driver->driver.name);
1806
1807 /* Walk the adapters that are already present */
1808 i2c_for_each_dev(driver, __process_new_driver);
1809
1810 return 0;
1811}
1812EXPORT_SYMBOL(i2c_register_driver);
1813
1814static int __process_removed_driver(struct device *dev, void *data)
1815{
1816 if (dev->type == &i2c_adapter_type)
1817 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1818 return 0;
1819}
1820
1821/**
1822 * i2c_del_driver - unregister I2C driver
1823 * @driver: the driver being unregistered
1824 * Context: can sleep
1825 */
1826void i2c_del_driver(struct i2c_driver *driver)
1827{
1828 i2c_for_each_dev(driver, __process_removed_driver);
1829
1830 driver_unregister(&driver->driver);
1831 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1832}
1833EXPORT_SYMBOL(i2c_del_driver);
1834
1835/* ------------------------------------------------------------------------- */
1836
1837struct i2c_cmd_arg {
1838 unsigned cmd;
1839 void *arg;
1840};
1841
1842static int i2c_cmd(struct device *dev, void *_arg)
1843{
1844 struct i2c_client *client = i2c_verify_client(dev);
1845 struct i2c_cmd_arg *arg = _arg;
1846 struct i2c_driver *driver;
1847
1848 if (!client || !client->dev.driver)
1849 return 0;
1850
1851 driver = to_i2c_driver(client->dev.driver);
1852 if (driver->command)
1853 driver->command(client, arg->cmd, arg->arg);
1854 return 0;
1855}
1856
1857void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1858{
1859 struct i2c_cmd_arg cmd_arg;
1860
1861 cmd_arg.cmd = cmd;
1862 cmd_arg.arg = arg;
1863 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1864}
1865EXPORT_SYMBOL(i2c_clients_command);
1866
1867static int __init i2c_init(void)
1868{
1869 int retval;
1870
1871 retval = of_alias_get_highest_id("i2c");
1872
1873 down_write(&__i2c_board_lock);
1874 if (retval >= __i2c_first_dynamic_bus_num)
1875 __i2c_first_dynamic_bus_num = retval + 1;
1876 up_write(&__i2c_board_lock);
1877
1878 retval = bus_register(&i2c_bus_type);
1879 if (retval)
1880 return retval;
1881
1882 is_registered = true;
1883
1884#ifdef CONFIG_I2C_COMPAT
1885 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1886 if (!i2c_adapter_compat_class) {
1887 retval = -ENOMEM;
1888 goto bus_err;
1889 }
1890#endif
1891 retval = i2c_add_driver(&dummy_driver);
1892 if (retval)
1893 goto class_err;
1894
1895 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1896 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1897 if (IS_ENABLED(CONFIG_ACPI))
1898 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1899
1900 return 0;
1901
1902class_err:
1903#ifdef CONFIG_I2C_COMPAT
1904 class_compat_unregister(i2c_adapter_compat_class);
1905bus_err:
1906#endif
1907 is_registered = false;
1908 bus_unregister(&i2c_bus_type);
1909 return retval;
1910}
1911
1912static void __exit i2c_exit(void)
1913{
1914 if (IS_ENABLED(CONFIG_ACPI))
1915 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1916 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1917 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1918 i2c_del_driver(&dummy_driver);
1919#ifdef CONFIG_I2C_COMPAT
1920 class_compat_unregister(i2c_adapter_compat_class);
1921#endif
1922 bus_unregister(&i2c_bus_type);
1923 tracepoint_synchronize_unregister();
1924}
1925
1926/* We must initialize early, because some subsystems register i2c drivers
1927 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1928 */
1929postcore_initcall(i2c_init);
1930module_exit(i2c_exit);
1931
1932/* ----------------------------------------------------
1933 * the functional interface to the i2c busses.
1934 * ----------------------------------------------------
1935 */
1936
1937/* Check if val is exceeding the quirk IFF quirk is non 0 */
1938#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1939
1940static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1941{
1942 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1943 err_msg, msg->addr, msg->len,
1944 msg->flags & I2C_M_RD ? "read" : "write");
1945 return -EOPNOTSUPP;
1946}
1947
1948static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1949{
1950 const struct i2c_adapter_quirks *q = adap->quirks;
1951 int max_num = q->max_num_msgs, i;
1952 bool do_len_check = true;
1953
1954 if (q->flags & I2C_AQ_COMB) {
1955 max_num = 2;
1956
1957 /* special checks for combined messages */
1958 if (num == 2) {
1959 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1960 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1961
1962 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1963 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1964
1965 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1966 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1967
1968 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1969 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1970
1971 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1972 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1973
1974 do_len_check = false;
1975 }
1976 }
1977
1978 if (i2c_quirk_exceeded(num, max_num))
1979 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1980
1981 for (i = 0; i < num; i++) {
1982 u16 len = msgs[i].len;
1983
1984 if (msgs[i].flags & I2C_M_RD) {
1985 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1986 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1987
1988 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1989 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1990 } else {
1991 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1992 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1993
1994 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1995 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1996 }
1997 }
1998
1999 return 0;
2000}
2001
2002/**
2003 * __i2c_transfer - unlocked flavor of i2c_transfer
2004 * @adap: Handle to I2C bus
2005 * @msgs: One or more messages to execute before STOP is issued to
2006 * terminate the operation; each message begins with a START.
2007 * @num: Number of messages to be executed.
2008 *
2009 * Returns negative errno, else the number of messages executed.
2010 *
2011 * Adapter lock must be held when calling this function. No debug logging
2012 * takes place. adap->algo->master_xfer existence isn't checked.
2013 */
2014int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2015{
2016 unsigned long orig_jiffies;
2017 int ret, try;
2018
2019 if (WARN_ON(!msgs || num < 1))
2020 return -EINVAL;
2021
2022 ret = __i2c_check_suspended(adap);
2023 if (ret)
2024 return ret;
2025
2026 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2027 return -EOPNOTSUPP;
2028
2029 /*
2030 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2031 * enabled. This is an efficient way of keeping the for-loop from
2032 * being executed when not needed.
2033 */
2034 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2035 int i;
2036 for (i = 0; i < num; i++)
2037 if (msgs[i].flags & I2C_M_RD)
2038 trace_i2c_read(adap, &msgs[i], i);
2039 else
2040 trace_i2c_write(adap, &msgs[i], i);
2041 }
2042
2043 /* Retry automatically on arbitration loss */
2044 orig_jiffies = jiffies;
2045 for (ret = 0, try = 0; try <= adap->retries; try++) {
2046 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2047 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2048 else
2049 ret = adap->algo->master_xfer(adap, msgs, num);
2050
2051 if (ret != -EAGAIN)
2052 break;
2053 if (time_after(jiffies, orig_jiffies + adap->timeout))
2054 break;
2055 }
2056
2057 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2058 int i;
2059 for (i = 0; i < ret; i++)
2060 if (msgs[i].flags & I2C_M_RD)
2061 trace_i2c_reply(adap, &msgs[i], i);
2062 trace_i2c_result(adap, num, ret);
2063 }
2064
2065 return ret;
2066}
2067EXPORT_SYMBOL(__i2c_transfer);
2068
2069/**
2070 * i2c_transfer - execute a single or combined I2C message
2071 * @adap: Handle to I2C bus
2072 * @msgs: One or more messages to execute before STOP is issued to
2073 * terminate the operation; each message begins with a START.
2074 * @num: Number of messages to be executed.
2075 *
2076 * Returns negative errno, else the number of messages executed.
2077 *
2078 * Note that there is no requirement that each message be sent to
2079 * the same slave address, although that is the most common model.
2080 */
2081int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2082{
2083 int ret;
2084
2085 if (!adap->algo->master_xfer) {
2086 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2087 return -EOPNOTSUPP;
2088 }
2089
2090 /* REVISIT the fault reporting model here is weak:
2091 *
2092 * - When we get an error after receiving N bytes from a slave,
2093 * there is no way to report "N".
2094 *
2095 * - When we get a NAK after transmitting N bytes to a slave,
2096 * there is no way to report "N" ... or to let the master
2097 * continue executing the rest of this combined message, if
2098 * that's the appropriate response.
2099 *
2100 * - When for example "num" is two and we successfully complete
2101 * the first message but get an error part way through the
2102 * second, it's unclear whether that should be reported as
2103 * one (discarding status on the second message) or errno
2104 * (discarding status on the first one).
2105 */
2106 ret = __i2c_lock_bus_helper(adap);
2107 if (ret)
2108 return ret;
2109
2110 ret = __i2c_transfer(adap, msgs, num);
2111 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2112
2113 return ret;
2114}
2115EXPORT_SYMBOL(i2c_transfer);
2116
2117/**
2118 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2119 * to/from a buffer
2120 * @client: Handle to slave device
2121 * @buf: Where the data is stored
2122 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2123 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2124 *
2125 * Returns negative errno, or else the number of bytes transferred.
2126 */
2127int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2128 int count, u16 flags)
2129{
2130 int ret;
2131 struct i2c_msg msg = {
2132 .addr = client->addr,
2133 .flags = flags | (client->flags & I2C_M_TEN),
2134 .len = count,
2135 .buf = buf,
2136 };
2137
2138 ret = i2c_transfer(client->adapter, &msg, 1);
2139
2140 /*
2141 * If everything went ok (i.e. 1 msg transferred), return #bytes
2142 * transferred, else error code.
2143 */
2144 return (ret == 1) ? count : ret;
2145}
2146EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2147
2148/**
2149 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2150 * @client: The device to query
2151 * @id: The queried information
2152 *
2153 * Returns negative errno on error, zero on success.
2154 */
2155int i2c_get_device_id(const struct i2c_client *client,
2156 struct i2c_device_identity *id)
2157{
2158 struct i2c_adapter *adap = client->adapter;
2159 union i2c_smbus_data raw_id;
2160 int ret;
2161
2162 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2163 return -EOPNOTSUPP;
2164
2165 raw_id.block[0] = 3;
2166 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2167 I2C_SMBUS_READ, client->addr << 1,
2168 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2169 if (ret)
2170 return ret;
2171
2172 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2173 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2174 id->die_revision = raw_id.block[3] & 0x7;
2175 return 0;
2176}
2177EXPORT_SYMBOL_GPL(i2c_get_device_id);
2178
2179/* ----------------------------------------------------
2180 * the i2c address scanning function
2181 * Will not work for 10-bit addresses!
2182 * ----------------------------------------------------
2183 */
2184
2185/*
2186 * Legacy default probe function, mostly relevant for SMBus. The default
2187 * probe method is a quick write, but it is known to corrupt the 24RF08
2188 * EEPROMs due to a state machine bug, and could also irreversibly
2189 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2190 * we use a short byte read instead. Also, some bus drivers don't implement
2191 * quick write, so we fallback to a byte read in that case too.
2192 * On x86, there is another special case for FSC hardware monitoring chips,
2193 * which want regular byte reads (address 0x73.) Fortunately, these are the
2194 * only known chips using this I2C address on PC hardware.
2195 * Returns 1 if probe succeeded, 0 if not.
2196 */
2197static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2198{
2199 int err;
2200 union i2c_smbus_data dummy;
2201
2202#ifdef CONFIG_X86
2203 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2204 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2205 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2206 I2C_SMBUS_BYTE_DATA, &dummy);
2207 else
2208#endif
2209 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2210 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2211 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2212 I2C_SMBUS_QUICK, NULL);
2213 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2214 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2215 I2C_SMBUS_BYTE, &dummy);
2216 else {
2217 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2218 addr);
2219 err = -EOPNOTSUPP;
2220 }
2221
2222 return err >= 0;
2223}
2224
2225static int i2c_detect_address(struct i2c_client *temp_client,
2226 struct i2c_driver *driver)
2227{
2228 struct i2c_board_info info;
2229 struct i2c_adapter *adapter = temp_client->adapter;
2230 int addr = temp_client->addr;
2231 int err;
2232
2233 /* Make sure the address is valid */
2234 err = i2c_check_7bit_addr_validity_strict(addr);
2235 if (err) {
2236 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2237 addr);
2238 return err;
2239 }
2240
2241 /* Skip if already in use (7 bit, no need to encode flags) */
2242 if (i2c_check_addr_busy(adapter, addr))
2243 return 0;
2244
2245 /* Make sure there is something at this address */
2246 if (!i2c_default_probe(adapter, addr))
2247 return 0;
2248
2249 /* Finally call the custom detection function */
2250 memset(&info, 0, sizeof(struct i2c_board_info));
2251 info.addr = addr;
2252 err = driver->detect(temp_client, &info);
2253 if (err) {
2254 /* -ENODEV is returned if the detection fails. We catch it
2255 here as this isn't an error. */
2256 return err == -ENODEV ? 0 : err;
2257 }
2258
2259 /* Consistency check */
2260 if (info.type[0] == '\0') {
2261 dev_err(&adapter->dev,
2262 "%s detection function provided no name for 0x%x\n",
2263 driver->driver.name, addr);
2264 } else {
2265 struct i2c_client *client;
2266
2267 /* Detection succeeded, instantiate the device */
2268 if (adapter->class & I2C_CLASS_DEPRECATED)
2269 dev_warn(&adapter->dev,
2270 "This adapter will soon drop class based instantiation of devices. "
2271 "Please make sure client 0x%02x gets instantiated by other means. "
2272 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2273 info.addr);
2274
2275 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2276 info.type, info.addr);
2277 client = i2c_new_client_device(adapter, &info);
2278 if (!IS_ERR(client))
2279 list_add_tail(&client->detected, &driver->clients);
2280 else
2281 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2282 info.type, info.addr);
2283 }
2284 return 0;
2285}
2286
2287static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2288{
2289 const unsigned short *address_list;
2290 struct i2c_client *temp_client;
2291 int i, err = 0;
2292
2293 address_list = driver->address_list;
2294 if (!driver->detect || !address_list)
2295 return 0;
2296
2297 /* Warn that the adapter lost class based instantiation */
2298 if (adapter->class == I2C_CLASS_DEPRECATED) {
2299 dev_dbg(&adapter->dev,
2300 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2301 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2302 driver->driver.name);
2303 return 0;
2304 }
2305
2306 /* Stop here if the classes do not match */
2307 if (!(adapter->class & driver->class))
2308 return 0;
2309
2310 /* Set up a temporary client to help detect callback */
2311 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2312 if (!temp_client)
2313 return -ENOMEM;
2314 temp_client->adapter = adapter;
2315
2316 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2317 dev_dbg(&adapter->dev,
2318 "found normal entry for adapter %d, addr 0x%02x\n",
2319 i2c_adapter_id(adapter), address_list[i]);
2320 temp_client->addr = address_list[i];
2321 err = i2c_detect_address(temp_client, driver);
2322 if (unlikely(err))
2323 break;
2324 }
2325
2326 kfree(temp_client);
2327 return err;
2328}
2329
2330int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2331{
2332 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2333 I2C_SMBUS_QUICK, NULL) >= 0;
2334}
2335EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2336
2337struct i2c_client *
2338i2c_new_scanned_device(struct i2c_adapter *adap,
2339 struct i2c_board_info *info,
2340 unsigned short const *addr_list,
2341 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2342{
2343 int i;
2344
2345 if (!probe)
2346 probe = i2c_default_probe;
2347
2348 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2349 /* Check address validity */
2350 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2351 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2352 addr_list[i]);
2353 continue;
2354 }
2355
2356 /* Check address availability (7 bit, no need to encode flags) */
2357 if (i2c_check_addr_busy(adap, addr_list[i])) {
2358 dev_dbg(&adap->dev,
2359 "Address 0x%02x already in use, not probing\n",
2360 addr_list[i]);
2361 continue;
2362 }
2363
2364 /* Test address responsiveness */
2365 if (probe(adap, addr_list[i]))
2366 break;
2367 }
2368
2369 if (addr_list[i] == I2C_CLIENT_END) {
2370 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2371 return ERR_PTR(-ENODEV);
2372 }
2373
2374 info->addr = addr_list[i];
2375 return i2c_new_client_device(adap, info);
2376}
2377EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2378
2379struct i2c_adapter *i2c_get_adapter(int nr)
2380{
2381 struct i2c_adapter *adapter;
2382
2383 mutex_lock(&core_lock);
2384 adapter = idr_find(&i2c_adapter_idr, nr);
2385 if (!adapter)
2386 goto exit;
2387
2388 if (try_module_get(adapter->owner))
2389 get_device(&adapter->dev);
2390 else
2391 adapter = NULL;
2392
2393 exit:
2394 mutex_unlock(&core_lock);
2395 return adapter;
2396}
2397EXPORT_SYMBOL(i2c_get_adapter);
2398
2399void i2c_put_adapter(struct i2c_adapter *adap)
2400{
2401 if (!adap)
2402 return;
2403
2404 put_device(&adap->dev);
2405 module_put(adap->owner);
2406}
2407EXPORT_SYMBOL(i2c_put_adapter);
2408
2409/**
2410 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2411 * @msg: the message to be checked
2412 * @threshold: the minimum number of bytes for which using DMA makes sense.
2413 * Should at least be 1.
2414 *
2415 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2416 * Or a valid pointer to be used with DMA. After use, release it by
2417 * calling i2c_put_dma_safe_msg_buf().
2418 *
2419 * This function must only be called from process context!
2420 */
2421u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2422{
2423 /* also skip 0-length msgs for bogus thresholds of 0 */
2424 if (!threshold)
2425 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2426 msg->addr);
2427 if (msg->len < threshold || msg->len == 0)
2428 return NULL;
2429
2430 if (msg->flags & I2C_M_DMA_SAFE)
2431 return msg->buf;
2432
2433 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2434 msg->addr, msg->len);
2435
2436 if (msg->flags & I2C_M_RD)
2437 return kzalloc(msg->len, GFP_KERNEL);
2438 else
2439 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2440}
2441EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2442
2443/**
2444 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2445 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2446 * @msg: the message which the buffer corresponds to
2447 * @xferred: bool saying if the message was transferred
2448 */
2449void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2450{
2451 if (!buf || buf == msg->buf)
2452 return;
2453
2454 if (xferred && msg->flags & I2C_M_RD)
2455 memcpy(msg->buf, buf, msg->len);
2456
2457 kfree(buf);
2458}
2459EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2460
2461MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2462MODULE_DESCRIPTION("I2C-Bus main module");
2463MODULE_LICENSE("GPL");