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