1/*
2 * Linux I2C core
3 *
4 * Copyright (C) 1995-99 Simon G. Vogl
5 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
6 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
7 * Michael Lawnick <michael.lawnick.ext@nsn.com>
8 *
9 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
10 *
11 * This program is free software; you can redistribute it and/or modify it
12 * under the terms of the GNU General Public License as published by the Free
13 * Software Foundation; either version 2 of the License, or (at your option)
14 * any later version.
15 *
16 * This program is distributed in the hope that it will be useful, but WITHOUT
17 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18 * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19 */
20
21#define pr_fmt(fmt) "i2c-core: " fmt
22
23#include <dt-bindings/i2c/i2c.h>
24#include <linux/acpi.h>
25#include <linux/clk/clk-conf.h>
26#include <linux/completion.h>
27#include <linux/delay.h>
28#include <linux/err.h>
29#include <linux/errno.h>
30#include <linux/gpio/consumer.h>
31#include <linux/i2c.h>
32#include <linux/i2c-smbus.h>
33#include <linux/idr.h>
34#include <linux/init.h>
35#include <linux/irqflags.h>
36#include <linux/jump_label.h>
37#include <linux/kernel.h>
38#include <linux/module.h>
39#include <linux/mutex.h>
40#include <linux/of_device.h>
41#include <linux/of.h>
42#include <linux/of_irq.h>
43#include <linux/pm_domain.h>
44#include <linux/pm_runtime.h>
45#include <linux/pm_wakeirq.h>
46#include <linux/property.h>
47#include <linux/rwsem.h>
48#include <linux/slab.h>
49
50#include "i2c-core.h"
51
52#define CREATE_TRACE_POINTS
53#include <trace/events/i2c.h>
54
55#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
56#define I2C_ADDR_OFFSET_SLAVE 0x1000
57
58#define I2C_ADDR_7BITS_MAX 0x77
59#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
60
61#define I2C_ADDR_DEVICE_ID 0x7c
62
63/*
64 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
65 * deletion of detected devices are serialized
66 */
67static DEFINE_MUTEX(core_lock);
68static DEFINE_IDR(i2c_adapter_idr);
69
70static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
71
72static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
73static bool is_registered;
74
75int i2c_transfer_trace_reg(void)
76{
77 static_branch_inc(&i2c_trace_msg_key);
78 return 0;
79}
80
81void i2c_transfer_trace_unreg(void)
82{
83 static_branch_dec(&i2c_trace_msg_key);
84}
85
86const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
87 const struct i2c_client *client)
88{
89 if (!(id && client))
90 return NULL;
91
92 while (id->name[0]) {
93 if (strcmp(client->name, id->name) == 0)
94 return id;
95 id++;
96 }
97 return NULL;
98}
99EXPORT_SYMBOL_GPL(i2c_match_id);
100
101static int i2c_device_match(struct device *dev, struct device_driver *drv)
102{
103 struct i2c_client *client = i2c_verify_client(dev);
104 struct i2c_driver *driver;
105
106
107 /* Attempt an OF style match */
108 if (i2c_of_match_device(drv->of_match_table, client))
109 return 1;
110
111 /* Then ACPI style match */
112 if (acpi_driver_match_device(dev, drv))
113 return 1;
114
115 driver = to_i2c_driver(drv);
116
117 /* Finally an I2C match */
118 if (i2c_match_id(driver->id_table, client))
119 return 1;
120
121 return 0;
122}
123
124static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
125{
126 struct i2c_client *client = to_i2c_client(dev);
127 int rc;
128
129 rc = of_device_uevent_modalias(dev, env);
130 if (rc != -ENODEV)
131 return rc;
132
133 rc = acpi_device_uevent_modalias(dev, env);
134 if (rc != -ENODEV)
135 return rc;
136
137 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
138}
139
140/* i2c bus recovery routines */
141static int get_scl_gpio_value(struct i2c_adapter *adap)
142{
143 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
144}
145
146static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
147{
148 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
149}
150
151static int get_sda_gpio_value(struct i2c_adapter *adap)
152{
153 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
154}
155
156static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
157{
158 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
159}
160
161static int i2c_generic_bus_free(struct i2c_adapter *adap)
162{
163 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
164 int ret = -EOPNOTSUPP;
165
166 if (bri->get_bus_free)
167 ret = bri->get_bus_free(adap);
168 else if (bri->get_sda)
169 ret = bri->get_sda(adap);
170
171 if (ret < 0)
172 return ret;
173
174 return ret ? 0 : -EBUSY;
175}
176
177/*
178 * We are generating clock pulses. ndelay() determines durating of clk pulses.
179 * We will generate clock with rate 100 KHz and so duration of both clock levels
180 * is: delay in ns = (10^6 / 100) / 2
181 */
182#define RECOVERY_NDELAY 5000
183#define RECOVERY_CLK_CNT 9
184
185int i2c_generic_scl_recovery(struct i2c_adapter *adap)
186{
187 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
188 int i = 0, scl = 1, ret;
189
190 if (bri->prepare_recovery)
191 bri->prepare_recovery(adap);
192
193 /*
194 * If we can set SDA, we will always create a STOP to ensure additional
195 * pulses will do no harm. This is achieved by letting SDA follow SCL
196 * half a cycle later. Check the 'incomplete_write_byte' fault injector
197 * for details.
198 */
199 bri->set_scl(adap, scl);
200 ndelay(RECOVERY_NDELAY / 2);
201 if (bri->set_sda)
202 bri->set_sda(adap, scl);
203 ndelay(RECOVERY_NDELAY / 2);
204
205 /*
206 * By this time SCL is high, as we need to give 9 falling-rising edges
207 */
208 while (i++ < RECOVERY_CLK_CNT * 2) {
209 if (scl) {
210 /* SCL shouldn't be low here */
211 if (!bri->get_scl(adap)) {
212 dev_err(&adap->dev,
213 "SCL is stuck low, exit recovery\n");
214 ret = -EBUSY;
215 break;
216 }
217 }
218
219 scl = !scl;
220 bri->set_scl(adap, scl);
221 /* Creating STOP again, see above */
222 ndelay(RECOVERY_NDELAY / 2);
223 if (bri->set_sda)
224 bri->set_sda(adap, scl);
225 ndelay(RECOVERY_NDELAY / 2);
226
227 if (scl) {
228 ret = i2c_generic_bus_free(adap);
229 if (ret == 0)
230 break;
231 }
232 }
233
234 /* If we can't check bus status, assume recovery worked */
235 if (ret == -EOPNOTSUPP)
236 ret = 0;
237
238 if (bri->unprepare_recovery)
239 bri->unprepare_recovery(adap);
240
241 return ret;
242}
243EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
244
245int i2c_recover_bus(struct i2c_adapter *adap)
246{
247 if (!adap->bus_recovery_info)
248 return -EOPNOTSUPP;
249
250 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
251 return adap->bus_recovery_info->recover_bus(adap);
252}
253EXPORT_SYMBOL_GPL(i2c_recover_bus);
254
255static void i2c_init_recovery(struct i2c_adapter *adap)
256{
257 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
258 char *err_str;
259
260 if (!bri)
261 return;
262
263 if (!bri->recover_bus) {
264 err_str = "no recover_bus() found";
265 goto err;
266 }
267
268 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
269 bri->get_scl = get_scl_gpio_value;
270 bri->set_scl = set_scl_gpio_value;
271 if (bri->sda_gpiod) {
272 bri->get_sda = get_sda_gpio_value;
273 /* FIXME: add proper flag instead of '0' once available */
274 if (gpiod_get_direction(bri->sda_gpiod) == 0)
275 bri->set_sda = set_sda_gpio_value;
276 }
277 return;
278 }
279
280 if (bri->recover_bus == i2c_generic_scl_recovery) {
281 /* Generic SCL recovery */
282 if (!bri->set_scl || !bri->get_scl) {
283 err_str = "no {get|set}_scl() found";
284 goto err;
285 }
286 if (!bri->set_sda && !bri->get_sda) {
287 err_str = "either get_sda() or set_sda() needed";
288 goto err;
289 }
290 }
291
292 return;
293 err:
294 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
295 adap->bus_recovery_info = NULL;
296}
297
298static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
299{
300 struct i2c_adapter *adap = client->adapter;
301 unsigned int irq;
302
303 if (!adap->host_notify_domain)
304 return -ENXIO;
305
306 if (client->flags & I2C_CLIENT_TEN)
307 return -EINVAL;
308
309 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
310
311 return irq > 0 ? irq : -ENXIO;
312}
313
314static int i2c_device_probe(struct device *dev)
315{
316 struct i2c_client *client = i2c_verify_client(dev);
317 struct i2c_driver *driver;
318 int status;
319
320 if (!client)
321 return 0;
322
323 driver = to_i2c_driver(dev->driver);
324
325 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
326 int irq = -ENOENT;
327
328 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
329 dev_dbg(dev, "Using Host Notify IRQ\n");
330 irq = i2c_smbus_host_notify_to_irq(client);
331 } else if (dev->of_node) {
332 irq = of_irq_get_byname(dev->of_node, "irq");
333 if (irq == -EINVAL || irq == -ENODATA)
334 irq = of_irq_get(dev->of_node, 0);
335 } else if (ACPI_COMPANION(dev)) {
336 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
337 }
338 if (irq == -EPROBE_DEFER)
339 return irq;
340
341 if (irq < 0)
342 irq = 0;
343
344 client->irq = irq;
345 }
346
347 /*
348 * An I2C ID table is not mandatory, if and only if, a suitable OF
349 * or ACPI ID table is supplied for the probing device.
350 */
351 if (!driver->id_table &&
352 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
353 !i2c_of_match_device(dev->driver->of_match_table, client))
354 return -ENODEV;
355
356 if (client->flags & I2C_CLIENT_WAKE) {
357 int wakeirq = -ENOENT;
358
359 if (dev->of_node) {
360 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
361 if (wakeirq == -EPROBE_DEFER)
362 return wakeirq;
363 }
364
365 device_init_wakeup(&client->dev, true);
366
367 if (wakeirq > 0 && wakeirq != client->irq)
368 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
369 else if (client->irq > 0)
370 status = dev_pm_set_wake_irq(dev, client->irq);
371 else
372 status = 0;
373
374 if (status)
375 dev_warn(&client->dev, "failed to set up wakeup irq\n");
376 }
377
378 dev_dbg(dev, "probe\n");
379
380 status = of_clk_set_defaults(dev->of_node, false);
381 if (status < 0)
382 goto err_clear_wakeup_irq;
383
384 status = dev_pm_domain_attach(&client->dev, true);
385 if (status)
386 goto err_clear_wakeup_irq;
387
388 /*
389 * When there are no more users of probe(),
390 * rename probe_new to probe.
391 */
392 if (driver->probe_new)
393 status = driver->probe_new(client);
394 else if (driver->probe)
395 status = driver->probe(client,
396 i2c_match_id(driver->id_table, client));
397 else
398 status = -EINVAL;
399
400 if (status)
401 goto err_detach_pm_domain;
402
403 return 0;
404
405err_detach_pm_domain:
406 dev_pm_domain_detach(&client->dev, true);
407err_clear_wakeup_irq:
408 dev_pm_clear_wake_irq(&client->dev);
409 device_init_wakeup(&client->dev, false);
410 return status;
411}
412
413static int i2c_device_remove(struct device *dev)
414{
415 struct i2c_client *client = i2c_verify_client(dev);
416 struct i2c_driver *driver;
417 int status = 0;
418
419 if (!client || !dev->driver)
420 return 0;
421
422 driver = to_i2c_driver(dev->driver);
423 if (driver->remove) {
424 dev_dbg(dev, "remove\n");
425 status = driver->remove(client);
426 }
427
428 dev_pm_domain_detach(&client->dev, true);
429
430 dev_pm_clear_wake_irq(&client->dev);
431 device_init_wakeup(&client->dev, false);
432
433 client->irq = client->init_irq;
434
435 return status;
436}
437
438static void i2c_device_shutdown(struct device *dev)
439{
440 struct i2c_client *client = i2c_verify_client(dev);
441 struct i2c_driver *driver;
442
443 if (!client || !dev->driver)
444 return;
445 driver = to_i2c_driver(dev->driver);
446 if (driver->shutdown)
447 driver->shutdown(client);
448}
449
450static void i2c_client_dev_release(struct device *dev)
451{
452 kfree(to_i2c_client(dev));
453}
454
455static ssize_t
456show_name(struct device *dev, struct device_attribute *attr, char *buf)
457{
458 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
459 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
460}
461static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
462
463static ssize_t
464show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
465{
466 struct i2c_client *client = to_i2c_client(dev);
467 int len;
468
469 len = of_device_modalias(dev, buf, PAGE_SIZE);
470 if (len != -ENODEV)
471 return len;
472
473 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
474 if (len != -ENODEV)
475 return len;
476
477 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
478}
479static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
480
481static struct attribute *i2c_dev_attrs[] = {
482 &dev_attr_name.attr,
483 /* modalias helps coldplug: modprobe $(cat .../modalias) */
484 &dev_attr_modalias.attr,
485 NULL
486};
487ATTRIBUTE_GROUPS(i2c_dev);
488
489struct bus_type i2c_bus_type = {
490 .name = "i2c",
491 .match = i2c_device_match,
492 .probe = i2c_device_probe,
493 .remove = i2c_device_remove,
494 .shutdown = i2c_device_shutdown,
495};
496EXPORT_SYMBOL_GPL(i2c_bus_type);
497
498struct device_type i2c_client_type = {
499 .groups = i2c_dev_groups,
500 .uevent = i2c_device_uevent,
501 .release = i2c_client_dev_release,
502};
503EXPORT_SYMBOL_GPL(i2c_client_type);
504
505
506/**
507 * i2c_verify_client - return parameter as i2c_client, or NULL
508 * @dev: device, probably from some driver model iterator
509 *
510 * When traversing the driver model tree, perhaps using driver model
511 * iterators like @device_for_each_child(), you can't assume very much
512 * about the nodes you find. Use this function to avoid oopses caused
513 * by wrongly treating some non-I2C device as an i2c_client.
514 */
515struct i2c_client *i2c_verify_client(struct device *dev)
516{
517 return (dev->type == &i2c_client_type)
518 ? to_i2c_client(dev)
519 : NULL;
520}
521EXPORT_SYMBOL(i2c_verify_client);
522
523
524/* Return a unique address which takes the flags of the client into account */
525static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
526{
527 unsigned short addr = client->addr;
528
529 /* For some client flags, add an arbitrary offset to avoid collisions */
530 if (client->flags & I2C_CLIENT_TEN)
531 addr |= I2C_ADDR_OFFSET_TEN_BIT;
532
533 if (client->flags & I2C_CLIENT_SLAVE)
534 addr |= I2C_ADDR_OFFSET_SLAVE;
535
536 return addr;
537}
538
539/* This is a permissive address validity check, I2C address map constraints
540 * are purposely not enforced, except for the general call address. */
541static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
542{
543 if (flags & I2C_CLIENT_TEN) {
544 /* 10-bit address, all values are valid */
545 if (addr > 0x3ff)
546 return -EINVAL;
547 } else {
548 /* 7-bit address, reject the general call address */
549 if (addr == 0x00 || addr > 0x7f)
550 return -EINVAL;
551 }
552 return 0;
553}
554
555/* And this is a strict address validity check, used when probing. If a
556 * device uses a reserved address, then it shouldn't be probed. 7-bit
557 * addressing is assumed, 10-bit address devices are rare and should be
558 * explicitly enumerated. */
559int i2c_check_7bit_addr_validity_strict(unsigned short addr)
560{
561 /*
562 * Reserved addresses per I2C specification:
563 * 0x00 General call address / START byte
564 * 0x01 CBUS address
565 * 0x02 Reserved for different bus format
566 * 0x03 Reserved for future purposes
567 * 0x04-0x07 Hs-mode master code
568 * 0x78-0x7b 10-bit slave addressing
569 * 0x7c-0x7f Reserved for future purposes
570 */
571 if (addr < 0x08 || addr > 0x77)
572 return -EINVAL;
573 return 0;
574}
575
576static int __i2c_check_addr_busy(struct device *dev, void *addrp)
577{
578 struct i2c_client *client = i2c_verify_client(dev);
579 int addr = *(int *)addrp;
580
581 if (client && i2c_encode_flags_to_addr(client) == addr)
582 return -EBUSY;
583 return 0;
584}
585
586/* walk up mux tree */
587static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
588{
589 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
590 int result;
591
592 result = device_for_each_child(&adapter->dev, &addr,
593 __i2c_check_addr_busy);
594
595 if (!result && parent)
596 result = i2c_check_mux_parents(parent, addr);
597
598 return result;
599}
600
601/* recurse down mux tree */
602static int i2c_check_mux_children(struct device *dev, void *addrp)
603{
604 int result;
605
606 if (dev->type == &i2c_adapter_type)
607 result = device_for_each_child(dev, addrp,
608 i2c_check_mux_children);
609 else
610 result = __i2c_check_addr_busy(dev, addrp);
611
612 return result;
613}
614
615static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
616{
617 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
618 int result = 0;
619
620 if (parent)
621 result = i2c_check_mux_parents(parent, addr);
622
623 if (!result)
624 result = device_for_each_child(&adapter->dev, &addr,
625 i2c_check_mux_children);
626
627 return result;
628}
629
630/**
631 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
632 * @adapter: Target I2C bus segment
633 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
634 * locks only this branch in the adapter tree
635 */
636static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
637 unsigned int flags)
638{
639 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
640}
641
642/**
643 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
644 * @adapter: Target I2C bus segment
645 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
646 * trylocks only this branch in the adapter tree
647 */
648static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
649 unsigned int flags)
650{
651 return rt_mutex_trylock(&adapter->bus_lock);
652}
653
654/**
655 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
656 * @adapter: Target I2C bus segment
657 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
658 * unlocks only this branch in the adapter tree
659 */
660static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
661 unsigned int flags)
662{
663 rt_mutex_unlock(&adapter->bus_lock);
664}
665
666static void i2c_dev_set_name(struct i2c_adapter *adap,
667 struct i2c_client *client,
668 struct i2c_board_info const *info)
669{
670 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
671
672 if (info && info->dev_name) {
673 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
674 return;
675 }
676
677 if (adev) {
678 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
679 return;
680 }
681
682 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
683 i2c_encode_flags_to_addr(client));
684}
685
686static int i2c_dev_irq_from_resources(const struct resource *resources,
687 unsigned int num_resources)
688{
689 struct irq_data *irqd;
690 int i;
691
692 for (i = 0; i < num_resources; i++) {
693 const struct resource *r = &resources[i];
694
695 if (resource_type(r) != IORESOURCE_IRQ)
696 continue;
697
698 if (r->flags & IORESOURCE_BITS) {
699 irqd = irq_get_irq_data(r->start);
700 if (!irqd)
701 break;
702
703 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
704 }
705
706 return r->start;
707 }
708
709 return 0;
710}
711
712/**
713 * i2c_new_device - instantiate an i2c device
714 * @adap: the adapter managing the device
715 * @info: describes one I2C device; bus_num is ignored
716 * Context: can sleep
717 *
718 * Create an i2c device. Binding is handled through driver model
719 * probe()/remove() methods. A driver may be bound to this device when we
720 * return from this function, or any later moment (e.g. maybe hotplugging will
721 * load the driver module). This call is not appropriate for use by mainboard
722 * initialization logic, which usually runs during an arch_initcall() long
723 * before any i2c_adapter could exist.
724 *
725 * This returns the new i2c client, which may be saved for later use with
726 * i2c_unregister_device(); or NULL to indicate an error.
727 */
728struct i2c_client *
729i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
730{
731 struct i2c_client *client;
732 int status;
733
734 client = kzalloc(sizeof *client, GFP_KERNEL);
735 if (!client)
736 return NULL;
737
738 client->adapter = adap;
739
740 client->dev.platform_data = info->platform_data;
741 client->flags = info->flags;
742 client->addr = info->addr;
743
744 client->init_irq = info->irq;
745 if (!client->init_irq)
746 client->init_irq = i2c_dev_irq_from_resources(info->resources,
747 info->num_resources);
748 client->irq = client->init_irq;
749
750 strlcpy(client->name, info->type, sizeof(client->name));
751
752 status = i2c_check_addr_validity(client->addr, client->flags);
753 if (status) {
754 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
755 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
756 goto out_err_silent;
757 }
758
759 /* Check for address business */
760 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
761 if (status)
762 goto out_err;
763
764 client->dev.parent = &client->adapter->dev;
765 client->dev.bus = &i2c_bus_type;
766 client->dev.type = &i2c_client_type;
767 client->dev.of_node = of_node_get(info->of_node);
768 client->dev.fwnode = info->fwnode;
769
770 i2c_dev_set_name(adap, client, info);
771
772 if (info->properties) {
773 status = device_add_properties(&client->dev, info->properties);
774 if (status) {
775 dev_err(&adap->dev,
776 "Failed to add properties to client %s: %d\n",
777 client->name, status);
778 goto out_err_put_of_node;
779 }
780 }
781
782 status = device_register(&client->dev);
783 if (status)
784 goto out_free_props;
785
786 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
787 client->name, dev_name(&client->dev));
788
789 return client;
790
791out_free_props:
792 if (info->properties)
793 device_remove_properties(&client->dev);
794out_err_put_of_node:
795 of_node_put(info->of_node);
796out_err:
797 dev_err(&adap->dev,
798 "Failed to register i2c client %s at 0x%02x (%d)\n",
799 client->name, client->addr, status);
800out_err_silent:
801 kfree(client);
802 return NULL;
803}
804EXPORT_SYMBOL_GPL(i2c_new_device);
805
806
807/**
808 * i2c_unregister_device - reverse effect of i2c_new_device()
809 * @client: value returned from i2c_new_device()
810 * Context: can sleep
811 */
812void i2c_unregister_device(struct i2c_client *client)
813{
814 if (!client)
815 return;
816
817 if (client->dev.of_node) {
818 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
819 of_node_put(client->dev.of_node);
820 }
821
822 if (ACPI_COMPANION(&client->dev))
823 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
824 device_unregister(&client->dev);
825}
826EXPORT_SYMBOL_GPL(i2c_unregister_device);
827
828
829static const struct i2c_device_id dummy_id[] = {
830 { "dummy", 0 },
831 { },
832};
833
834static int dummy_probe(struct i2c_client *client,
835 const struct i2c_device_id *id)
836{
837 return 0;
838}
839
840static int dummy_remove(struct i2c_client *client)
841{
842 return 0;
843}
844
845static struct i2c_driver dummy_driver = {
846 .driver.name = "dummy",
847 .probe = dummy_probe,
848 .remove = dummy_remove,
849 .id_table = dummy_id,
850};
851
852/**
853 * i2c_new_dummy - return a new i2c device bound to a dummy driver
854 * @adapter: the adapter managing the device
855 * @address: seven bit address to be used
856 * Context: can sleep
857 *
858 * This returns an I2C client bound to the "dummy" driver, intended for use
859 * with devices that consume multiple addresses. Examples of such chips
860 * include various EEPROMS (like 24c04 and 24c08 models).
861 *
862 * These dummy devices have two main uses. First, most I2C and SMBus calls
863 * except i2c_transfer() need a client handle; the dummy will be that handle.
864 * And second, this prevents the specified address from being bound to a
865 * different driver.
866 *
867 * This returns the new i2c client, which should be saved for later use with
868 * i2c_unregister_device(); or NULL to indicate an error.
869 */
870struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
871{
872 struct i2c_board_info info = {
873 I2C_BOARD_INFO("dummy", address),
874 };
875
876 return i2c_new_device(adapter, &info);
877}
878EXPORT_SYMBOL_GPL(i2c_new_dummy);
879
880/**
881 * i2c_new_secondary_device - Helper to get the instantiated secondary address
882 * and create the associated device
883 * @client: Handle to the primary client
884 * @name: Handle to specify which secondary address to get
885 * @default_addr: Used as a fallback if no secondary address was specified
886 * Context: can sleep
887 *
888 * I2C clients can be composed of multiple I2C slaves bound together in a single
889 * component. The I2C client driver then binds to the master I2C slave and needs
890 * to create I2C dummy clients to communicate with all the other slaves.
891 *
892 * This function creates and returns an I2C dummy client whose I2C address is
893 * retrieved from the platform firmware based on the given slave name. If no
894 * address is specified by the firmware default_addr is used.
895 *
896 * On DT-based platforms the address is retrieved from the "reg" property entry
897 * cell whose "reg-names" value matches the slave name.
898 *
899 * This returns the new i2c client, which should be saved for later use with
900 * i2c_unregister_device(); or NULL to indicate an error.
901 */
902struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
903 const char *name,
904 u16 default_addr)
905{
906 struct device_node *np = client->dev.of_node;
907 u32 addr = default_addr;
908 int i;
909
910 if (np) {
911 i = of_property_match_string(np, "reg-names", name);
912 if (i >= 0)
913 of_property_read_u32_index(np, "reg", i, &addr);
914 }
915
916 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
917 return i2c_new_dummy(client->adapter, addr);
918}
919EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
920
921/* ------------------------------------------------------------------------- */
922
923/* I2C bus adapters -- one roots each I2C or SMBUS segment */
924
925static void i2c_adapter_dev_release(struct device *dev)
926{
927 struct i2c_adapter *adap = to_i2c_adapter(dev);
928 complete(&adap->dev_released);
929}
930
931unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
932{
933 unsigned int depth = 0;
934
935 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
936 depth++;
937
938 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
939 "adapter depth exceeds lockdep subclass limit\n");
940
941 return depth;
942}
943EXPORT_SYMBOL_GPL(i2c_adapter_depth);
944
945/*
946 * Let users instantiate I2C devices through sysfs. This can be used when
947 * platform initialization code doesn't contain the proper data for
948 * whatever reason. Also useful for drivers that do device detection and
949 * detection fails, either because the device uses an unexpected address,
950 * or this is a compatible device with different ID register values.
951 *
952 * Parameter checking may look overzealous, but we really don't want
953 * the user to provide incorrect parameters.
954 */
955static ssize_t
956i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
957 const char *buf, size_t count)
958{
959 struct i2c_adapter *adap = to_i2c_adapter(dev);
960 struct i2c_board_info info;
961 struct i2c_client *client;
962 char *blank, end;
963 int res;
964
965 memset(&info, 0, sizeof(struct i2c_board_info));
966
967 blank = strchr(buf, ' ');
968 if (!blank) {
969 dev_err(dev, "%s: Missing parameters\n", "new_device");
970 return -EINVAL;
971 }
972 if (blank - buf > I2C_NAME_SIZE - 1) {
973 dev_err(dev, "%s: Invalid device name\n", "new_device");
974 return -EINVAL;
975 }
976 memcpy(info.type, buf, blank - buf);
977
978 /* Parse remaining parameters, reject extra parameters */
979 res = sscanf(++blank, "%hi%c", &info.addr, &end);
980 if (res < 1) {
981 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
982 return -EINVAL;
983 }
984 if (res > 1 && end != '\n') {
985 dev_err(dev, "%s: Extra parameters\n", "new_device");
986 return -EINVAL;
987 }
988
989 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
990 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
991 info.flags |= I2C_CLIENT_TEN;
992 }
993
994 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
995 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
996 info.flags |= I2C_CLIENT_SLAVE;
997 }
998
999 client = i2c_new_device(adap, &info);
1000 if (!client)
1001 return -EINVAL;
1002
1003 /* Keep track of the added device */
1004 mutex_lock(&adap->userspace_clients_lock);
1005 list_add_tail(&client->detected, &adap->userspace_clients);
1006 mutex_unlock(&adap->userspace_clients_lock);
1007 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1008 info.type, info.addr);
1009
1010 return count;
1011}
1012static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1013
1014/*
1015 * And of course let the users delete the devices they instantiated, if
1016 * they got it wrong. This interface can only be used to delete devices
1017 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1018 * don't delete devices to which some kernel code still has references.
1019 *
1020 * Parameter checking may look overzealous, but we really don't want
1021 * the user to delete the wrong device.
1022 */
1023static ssize_t
1024i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1025 const char *buf, size_t count)
1026{
1027 struct i2c_adapter *adap = to_i2c_adapter(dev);
1028 struct i2c_client *client, *next;
1029 unsigned short addr;
1030 char end;
1031 int res;
1032
1033 /* Parse parameters, reject extra parameters */
1034 res = sscanf(buf, "%hi%c", &addr, &end);
1035 if (res < 1) {
1036 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1037 return -EINVAL;
1038 }
1039 if (res > 1 && end != '\n') {
1040 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1041 return -EINVAL;
1042 }
1043
1044 /* Make sure the device was added through sysfs */
1045 res = -ENOENT;
1046 mutex_lock_nested(&adap->userspace_clients_lock,
1047 i2c_adapter_depth(adap));
1048 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1049 detected) {
1050 if (i2c_encode_flags_to_addr(client) == addr) {
1051 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1052 "delete_device", client->name, client->addr);
1053
1054 list_del(&client->detected);
1055 i2c_unregister_device(client);
1056 res = count;
1057 break;
1058 }
1059 }
1060 mutex_unlock(&adap->userspace_clients_lock);
1061
1062 if (res < 0)
1063 dev_err(dev, "%s: Can't find device in list\n",
1064 "delete_device");
1065 return res;
1066}
1067static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1068 i2c_sysfs_delete_device);
1069
1070static struct attribute *i2c_adapter_attrs[] = {
1071 &dev_attr_name.attr,
1072 &dev_attr_new_device.attr,
1073 &dev_attr_delete_device.attr,
1074 NULL
1075};
1076ATTRIBUTE_GROUPS(i2c_adapter);
1077
1078struct device_type i2c_adapter_type = {
1079 .groups = i2c_adapter_groups,
1080 .release = i2c_adapter_dev_release,
1081};
1082EXPORT_SYMBOL_GPL(i2c_adapter_type);
1083
1084/**
1085 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1086 * @dev: device, probably from some driver model iterator
1087 *
1088 * When traversing the driver model tree, perhaps using driver model
1089 * iterators like @device_for_each_child(), you can't assume very much
1090 * about the nodes you find. Use this function to avoid oopses caused
1091 * by wrongly treating some non-I2C device as an i2c_adapter.
1092 */
1093struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1094{
1095 return (dev->type == &i2c_adapter_type)
1096 ? to_i2c_adapter(dev)
1097 : NULL;
1098}
1099EXPORT_SYMBOL(i2c_verify_adapter);
1100
1101#ifdef CONFIG_I2C_COMPAT
1102static struct class_compat *i2c_adapter_compat_class;
1103#endif
1104
1105static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1106{
1107 struct i2c_devinfo *devinfo;
1108
1109 down_read(&__i2c_board_lock);
1110 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1111 if (devinfo->busnum == adapter->nr
1112 && !i2c_new_device(adapter,
1113 &devinfo->board_info))
1114 dev_err(&adapter->dev,
1115 "Can't create device at 0x%02x\n",
1116 devinfo->board_info.addr);
1117 }
1118 up_read(&__i2c_board_lock);
1119}
1120
1121static int i2c_do_add_adapter(struct i2c_driver *driver,
1122 struct i2c_adapter *adap)
1123{
1124 /* Detect supported devices on that bus, and instantiate them */
1125 i2c_detect(adap, driver);
1126
1127 return 0;
1128}
1129
1130static int __process_new_adapter(struct device_driver *d, void *data)
1131{
1132 return i2c_do_add_adapter(to_i2c_driver(d), data);
1133}
1134
1135static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1136 .lock_bus = i2c_adapter_lock_bus,
1137 .trylock_bus = i2c_adapter_trylock_bus,
1138 .unlock_bus = i2c_adapter_unlock_bus,
1139};
1140
1141static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1142{
1143 struct irq_domain *domain = adap->host_notify_domain;
1144 irq_hw_number_t hwirq;
1145
1146 if (!domain)
1147 return;
1148
1149 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1150 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1151
1152 irq_domain_remove(domain);
1153 adap->host_notify_domain = NULL;
1154}
1155
1156static int i2c_host_notify_irq_map(struct irq_domain *h,
1157 unsigned int virq,
1158 irq_hw_number_t hw_irq_num)
1159{
1160 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1161
1162 return 0;
1163}
1164
1165static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1166 .map = i2c_host_notify_irq_map,
1167};
1168
1169static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1170{
1171 struct irq_domain *domain;
1172
1173 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1174 return 0;
1175
1176 domain = irq_domain_create_linear(adap->dev.fwnode,
1177 I2C_ADDR_7BITS_COUNT,
1178 &i2c_host_notify_irq_ops, adap);
1179 if (!domain)
1180 return -ENOMEM;
1181
1182 adap->host_notify_domain = domain;
1183
1184 return 0;
1185}
1186
1187/**
1188 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1189 * I2C client.
1190 * @adap: the adapter
1191 * @addr: the I2C address of the notifying device
1192 * Context: can't sleep
1193 *
1194 * Helper function to be called from an I2C bus driver's interrupt
1195 * handler. It will schedule the Host Notify IRQ.
1196 */
1197int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1198{
1199 int irq;
1200
1201 if (!adap)
1202 return -EINVAL;
1203
1204 irq = irq_find_mapping(adap->host_notify_domain, addr);
1205 if (irq <= 0)
1206 return -ENXIO;
1207
1208 generic_handle_irq(irq);
1209
1210 return 0;
1211}
1212EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1213
1214static int i2c_register_adapter(struct i2c_adapter *adap)
1215{
1216 int res = -EINVAL;
1217
1218 /* Can't register until after driver model init */
1219 if (WARN_ON(!is_registered)) {
1220 res = -EAGAIN;
1221 goto out_list;
1222 }
1223
1224 /* Sanity checks */
1225 if (WARN(!adap->name[0], "i2c adapter has no name"))
1226 goto out_list;
1227
1228 if (!adap->algo) {
1229 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1230 goto out_list;
1231 }
1232
1233 if (!adap->lock_ops)
1234 adap->lock_ops = &i2c_adapter_lock_ops;
1235
1236 adap->locked_flags = 0;
1237 rt_mutex_init(&adap->bus_lock);
1238 rt_mutex_init(&adap->mux_lock);
1239 mutex_init(&adap->userspace_clients_lock);
1240 INIT_LIST_HEAD(&adap->userspace_clients);
1241
1242 /* Set default timeout to 1 second if not already set */
1243 if (adap->timeout == 0)
1244 adap->timeout = HZ;
1245
1246 /* register soft irqs for Host Notify */
1247 res = i2c_setup_host_notify_irq_domain(adap);
1248 if (res) {
1249 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1250 adap->name, res);
1251 goto out_list;
1252 }
1253
1254 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1255 adap->dev.bus = &i2c_bus_type;
1256 adap->dev.type = &i2c_adapter_type;
1257 res = device_register(&adap->dev);
1258 if (res) {
1259 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1260 goto out_list;
1261 }
1262
1263 res = of_i2c_setup_smbus_alert(adap);
1264 if (res)
1265 goto out_reg;
1266
1267 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1268
1269 pm_runtime_no_callbacks(&adap->dev);
1270 pm_suspend_ignore_children(&adap->dev, true);
1271 pm_runtime_enable(&adap->dev);
1272
1273#ifdef CONFIG_I2C_COMPAT
1274 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1275 adap->dev.parent);
1276 if (res)
1277 dev_warn(&adap->dev,
1278 "Failed to create compatibility class link\n");
1279#endif
1280
1281 i2c_init_recovery(adap);
1282
1283 /* create pre-declared device nodes */
1284 of_i2c_register_devices(adap);
1285 i2c_acpi_register_devices(adap);
1286 i2c_acpi_install_space_handler(adap);
1287
1288 if (adap->nr < __i2c_first_dynamic_bus_num)
1289 i2c_scan_static_board_info(adap);
1290
1291 /* Notify drivers */
1292 mutex_lock(&core_lock);
1293 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1294 mutex_unlock(&core_lock);
1295
1296 return 0;
1297
1298out_reg:
1299 init_completion(&adap->dev_released);
1300 device_unregister(&adap->dev);
1301 wait_for_completion(&adap->dev_released);
1302out_list:
1303 mutex_lock(&core_lock);
1304 idr_remove(&i2c_adapter_idr, adap->nr);
1305 mutex_unlock(&core_lock);
1306 return res;
1307}
1308
1309/**
1310 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1311 * @adap: the adapter to register (with adap->nr initialized)
1312 * Context: can sleep
1313 *
1314 * See i2c_add_numbered_adapter() for details.
1315 */
1316static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1317{
1318 int id;
1319
1320 mutex_lock(&core_lock);
1321 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1322 mutex_unlock(&core_lock);
1323 if (WARN(id < 0, "couldn't get idr"))
1324 return id == -ENOSPC ? -EBUSY : id;
1325
1326 return i2c_register_adapter(adap);
1327}
1328
1329/**
1330 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1331 * @adapter: the adapter to add
1332 * Context: can sleep
1333 *
1334 * This routine is used to declare an I2C adapter when its bus number
1335 * doesn't matter or when its bus number is specified by an dt alias.
1336 * Examples of bases when the bus number doesn't matter: I2C adapters
1337 * dynamically added by USB links or PCI plugin cards.
1338 *
1339 * When this returns zero, a new bus number was allocated and stored
1340 * in adap->nr, and the specified adapter became available for clients.
1341 * Otherwise, a negative errno value is returned.
1342 */
1343int i2c_add_adapter(struct i2c_adapter *adapter)
1344{
1345 struct device *dev = &adapter->dev;
1346 int id;
1347
1348 if (dev->of_node) {
1349 id = of_alias_get_id(dev->of_node, "i2c");
1350 if (id >= 0) {
1351 adapter->nr = id;
1352 return __i2c_add_numbered_adapter(adapter);
1353 }
1354 }
1355
1356 mutex_lock(&core_lock);
1357 id = idr_alloc(&i2c_adapter_idr, adapter,
1358 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1359 mutex_unlock(&core_lock);
1360 if (WARN(id < 0, "couldn't get idr"))
1361 return id;
1362
1363 adapter->nr = id;
1364
1365 return i2c_register_adapter(adapter);
1366}
1367EXPORT_SYMBOL(i2c_add_adapter);
1368
1369/**
1370 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1371 * @adap: the adapter to register (with adap->nr initialized)
1372 * Context: can sleep
1373 *
1374 * This routine is used to declare an I2C adapter when its bus number
1375 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1376 * or otherwise built in to the system's mainboard, and where i2c_board_info
1377 * is used to properly configure I2C devices.
1378 *
1379 * If the requested bus number is set to -1, then this function will behave
1380 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1381 *
1382 * If no devices have pre-been declared for this bus, then be sure to
1383 * register the adapter before any dynamically allocated ones. Otherwise
1384 * the required bus ID may not be available.
1385 *
1386 * When this returns zero, the specified adapter became available for
1387 * clients using the bus number provided in adap->nr. Also, the table
1388 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1389 * and the appropriate driver model device nodes are created. Otherwise, a
1390 * negative errno value is returned.
1391 */
1392int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1393{
1394 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1395 return i2c_add_adapter(adap);
1396
1397 return __i2c_add_numbered_adapter(adap);
1398}
1399EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1400
1401static void i2c_do_del_adapter(struct i2c_driver *driver,
1402 struct i2c_adapter *adapter)
1403{
1404 struct i2c_client *client, *_n;
1405
1406 /* Remove the devices we created ourselves as the result of hardware
1407 * probing (using a driver's detect method) */
1408 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1409 if (client->adapter == adapter) {
1410 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1411 client->name, client->addr);
1412 list_del(&client->detected);
1413 i2c_unregister_device(client);
1414 }
1415 }
1416}
1417
1418static int __unregister_client(struct device *dev, void *dummy)
1419{
1420 struct i2c_client *client = i2c_verify_client(dev);
1421 if (client && strcmp(client->name, "dummy"))
1422 i2c_unregister_device(client);
1423 return 0;
1424}
1425
1426static int __unregister_dummy(struct device *dev, void *dummy)
1427{
1428 struct i2c_client *client = i2c_verify_client(dev);
1429 i2c_unregister_device(client);
1430 return 0;
1431}
1432
1433static int __process_removed_adapter(struct device_driver *d, void *data)
1434{
1435 i2c_do_del_adapter(to_i2c_driver(d), data);
1436 return 0;
1437}
1438
1439/**
1440 * i2c_del_adapter - unregister I2C adapter
1441 * @adap: the adapter being unregistered
1442 * Context: can sleep
1443 *
1444 * This unregisters an I2C adapter which was previously registered
1445 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1446 */
1447void i2c_del_adapter(struct i2c_adapter *adap)
1448{
1449 struct i2c_adapter *found;
1450 struct i2c_client *client, *next;
1451
1452 /* First make sure that this adapter was ever added */
1453 mutex_lock(&core_lock);
1454 found = idr_find(&i2c_adapter_idr, adap->nr);
1455 mutex_unlock(&core_lock);
1456 if (found != adap) {
1457 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1458 return;
1459 }
1460
1461 i2c_acpi_remove_space_handler(adap);
1462 /* Tell drivers about this removal */
1463 mutex_lock(&core_lock);
1464 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1465 __process_removed_adapter);
1466 mutex_unlock(&core_lock);
1467
1468 /* Remove devices instantiated from sysfs */
1469 mutex_lock_nested(&adap->userspace_clients_lock,
1470 i2c_adapter_depth(adap));
1471 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1472 detected) {
1473 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1474 client->addr);
1475 list_del(&client->detected);
1476 i2c_unregister_device(client);
1477 }
1478 mutex_unlock(&adap->userspace_clients_lock);
1479
1480 /* Detach any active clients. This can't fail, thus we do not
1481 * check the returned value. This is a two-pass process, because
1482 * we can't remove the dummy devices during the first pass: they
1483 * could have been instantiated by real devices wishing to clean
1484 * them up properly, so we give them a chance to do that first. */
1485 device_for_each_child(&adap->dev, NULL, __unregister_client);
1486 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1487
1488#ifdef CONFIG_I2C_COMPAT
1489 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1490 adap->dev.parent);
1491#endif
1492
1493 /* device name is gone after device_unregister */
1494 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1495
1496 pm_runtime_disable(&adap->dev);
1497
1498 i2c_host_notify_irq_teardown(adap);
1499
1500 /* wait until all references to the device are gone
1501 *
1502 * FIXME: This is old code and should ideally be replaced by an
1503 * alternative which results in decoupling the lifetime of the struct
1504 * device from the i2c_adapter, like spi or netdev do. Any solution
1505 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1506 */
1507 init_completion(&adap->dev_released);
1508 device_unregister(&adap->dev);
1509 wait_for_completion(&adap->dev_released);
1510
1511 /* free bus id */
1512 mutex_lock(&core_lock);
1513 idr_remove(&i2c_adapter_idr, adap->nr);
1514 mutex_unlock(&core_lock);
1515
1516 /* Clear the device structure in case this adapter is ever going to be
1517 added again */
1518 memset(&adap->dev, 0, sizeof(adap->dev));
1519}
1520EXPORT_SYMBOL(i2c_del_adapter);
1521
1522/**
1523 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1524 * @dev: The device to scan for I2C timing properties
1525 * @t: the i2c_timings struct to be filled with values
1526 * @use_defaults: bool to use sane defaults derived from the I2C specification
1527 * when properties are not found, otherwise use 0
1528 *
1529 * Scan the device for the generic I2C properties describing timing parameters
1530 * for the signal and fill the given struct with the results. If a property was
1531 * not found and use_defaults was true, then maximum timings are assumed which
1532 * are derived from the I2C specification. If use_defaults is not used, the
1533 * results will be 0, so drivers can apply their own defaults later. The latter
1534 * is mainly intended for avoiding regressions of existing drivers which want
1535 * to switch to this function. New drivers almost always should use the defaults.
1536 */
1537
1538void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1539{
1540 int ret;
1541
1542 memset(t, 0, sizeof(*t));
1543
1544 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1545 if (ret && use_defaults)
1546 t->bus_freq_hz = 100000;
1547
1548 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1549 if (ret && use_defaults) {
1550 if (t->bus_freq_hz <= 100000)
1551 t->scl_rise_ns = 1000;
1552 else if (t->bus_freq_hz <= 400000)
1553 t->scl_rise_ns = 300;
1554 else
1555 t->scl_rise_ns = 120;
1556 }
1557
1558 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1559 if (ret && use_defaults) {
1560 if (t->bus_freq_hz <= 400000)
1561 t->scl_fall_ns = 300;
1562 else
1563 t->scl_fall_ns = 120;
1564 }
1565
1566 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1567
1568 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1569 if (ret && use_defaults)
1570 t->sda_fall_ns = t->scl_fall_ns;
1571
1572 device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1573}
1574EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1575
1576/* ------------------------------------------------------------------------- */
1577
1578int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1579{
1580 int res;
1581
1582 mutex_lock(&core_lock);
1583 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1584 mutex_unlock(&core_lock);
1585
1586 return res;
1587}
1588EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1589
1590static int __process_new_driver(struct device *dev, void *data)
1591{
1592 if (dev->type != &i2c_adapter_type)
1593 return 0;
1594 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1595}
1596
1597/*
1598 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1599 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1600 */
1601
1602int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1603{
1604 int res;
1605
1606 /* Can't register until after driver model init */
1607 if (WARN_ON(!is_registered))
1608 return -EAGAIN;
1609
1610 /* add the driver to the list of i2c drivers in the driver core */
1611 driver->driver.owner = owner;
1612 driver->driver.bus = &i2c_bus_type;
1613 INIT_LIST_HEAD(&driver->clients);
1614
1615 /* When registration returns, the driver core
1616 * will have called probe() for all matching-but-unbound devices.
1617 */
1618 res = driver_register(&driver->driver);
1619 if (res)
1620 return res;
1621
1622 pr_debug("driver [%s] registered\n", driver->driver.name);
1623
1624 /* Walk the adapters that are already present */
1625 i2c_for_each_dev(driver, __process_new_driver);
1626
1627 return 0;
1628}
1629EXPORT_SYMBOL(i2c_register_driver);
1630
1631static int __process_removed_driver(struct device *dev, void *data)
1632{
1633 if (dev->type == &i2c_adapter_type)
1634 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1635 return 0;
1636}
1637
1638/**
1639 * i2c_del_driver - unregister I2C driver
1640 * @driver: the driver being unregistered
1641 * Context: can sleep
1642 */
1643void i2c_del_driver(struct i2c_driver *driver)
1644{
1645 i2c_for_each_dev(driver, __process_removed_driver);
1646
1647 driver_unregister(&driver->driver);
1648 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1649}
1650EXPORT_SYMBOL(i2c_del_driver);
1651
1652/* ------------------------------------------------------------------------- */
1653
1654/**
1655 * i2c_use_client - increments the reference count of the i2c client structure
1656 * @client: the client being referenced
1657 *
1658 * Each live reference to a client should be refcounted. The driver model does
1659 * that automatically as part of driver binding, so that most drivers don't
1660 * need to do this explicitly: they hold a reference until they're unbound
1661 * from the device.
1662 *
1663 * A pointer to the client with the incremented reference counter is returned.
1664 */
1665struct i2c_client *i2c_use_client(struct i2c_client *client)
1666{
1667 if (client && get_device(&client->dev))
1668 return client;
1669 return NULL;
1670}
1671EXPORT_SYMBOL(i2c_use_client);
1672
1673/**
1674 * i2c_release_client - release a use of the i2c client structure
1675 * @client: the client being no longer referenced
1676 *
1677 * Must be called when a user of a client is finished with it.
1678 */
1679void i2c_release_client(struct i2c_client *client)
1680{
1681 if (client)
1682 put_device(&client->dev);
1683}
1684EXPORT_SYMBOL(i2c_release_client);
1685
1686struct i2c_cmd_arg {
1687 unsigned cmd;
1688 void *arg;
1689};
1690
1691static int i2c_cmd(struct device *dev, void *_arg)
1692{
1693 struct i2c_client *client = i2c_verify_client(dev);
1694 struct i2c_cmd_arg *arg = _arg;
1695 struct i2c_driver *driver;
1696
1697 if (!client || !client->dev.driver)
1698 return 0;
1699
1700 driver = to_i2c_driver(client->dev.driver);
1701 if (driver->command)
1702 driver->command(client, arg->cmd, arg->arg);
1703 return 0;
1704}
1705
1706void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1707{
1708 struct i2c_cmd_arg cmd_arg;
1709
1710 cmd_arg.cmd = cmd;
1711 cmd_arg.arg = arg;
1712 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1713}
1714EXPORT_SYMBOL(i2c_clients_command);
1715
1716static int __init i2c_init(void)
1717{
1718 int retval;
1719
1720 retval = of_alias_get_highest_id("i2c");
1721
1722 down_write(&__i2c_board_lock);
1723 if (retval >= __i2c_first_dynamic_bus_num)
1724 __i2c_first_dynamic_bus_num = retval + 1;
1725 up_write(&__i2c_board_lock);
1726
1727 retval = bus_register(&i2c_bus_type);
1728 if (retval)
1729 return retval;
1730
1731 is_registered = true;
1732
1733#ifdef CONFIG_I2C_COMPAT
1734 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1735 if (!i2c_adapter_compat_class) {
1736 retval = -ENOMEM;
1737 goto bus_err;
1738 }
1739#endif
1740 retval = i2c_add_driver(&dummy_driver);
1741 if (retval)
1742 goto class_err;
1743
1744 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1745 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1746 if (IS_ENABLED(CONFIG_ACPI))
1747 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1748
1749 return 0;
1750
1751class_err:
1752#ifdef CONFIG_I2C_COMPAT
1753 class_compat_unregister(i2c_adapter_compat_class);
1754bus_err:
1755#endif
1756 is_registered = false;
1757 bus_unregister(&i2c_bus_type);
1758 return retval;
1759}
1760
1761static void __exit i2c_exit(void)
1762{
1763 if (IS_ENABLED(CONFIG_ACPI))
1764 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1765 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1766 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1767 i2c_del_driver(&dummy_driver);
1768#ifdef CONFIG_I2C_COMPAT
1769 class_compat_unregister(i2c_adapter_compat_class);
1770#endif
1771 bus_unregister(&i2c_bus_type);
1772 tracepoint_synchronize_unregister();
1773}
1774
1775/* We must initialize early, because some subsystems register i2c drivers
1776 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1777 */
1778postcore_initcall(i2c_init);
1779module_exit(i2c_exit);
1780
1781/* ----------------------------------------------------
1782 * the functional interface to the i2c busses.
1783 * ----------------------------------------------------
1784 */
1785
1786/* Check if val is exceeding the quirk IFF quirk is non 0 */
1787#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1788
1789static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1790{
1791 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1792 err_msg, msg->addr, msg->len,
1793 msg->flags & I2C_M_RD ? "read" : "write");
1794 return -EOPNOTSUPP;
1795}
1796
1797static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1798{
1799 const struct i2c_adapter_quirks *q = adap->quirks;
1800 int max_num = q->max_num_msgs, i;
1801 bool do_len_check = true;
1802
1803 if (q->flags & I2C_AQ_COMB) {
1804 max_num = 2;
1805
1806 /* special checks for combined messages */
1807 if (num == 2) {
1808 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1809 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1810
1811 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1812 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1813
1814 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1815 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1816
1817 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1818 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1819
1820 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1821 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1822
1823 do_len_check = false;
1824 }
1825 }
1826
1827 if (i2c_quirk_exceeded(num, max_num))
1828 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1829
1830 for (i = 0; i < num; i++) {
1831 u16 len = msgs[i].len;
1832
1833 if (msgs[i].flags & I2C_M_RD) {
1834 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1835 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1836
1837 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1838 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1839 } else {
1840 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1841 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1842
1843 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1844 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1845 }
1846 }
1847
1848 return 0;
1849}
1850
1851/**
1852 * __i2c_transfer - unlocked flavor of i2c_transfer
1853 * @adap: Handle to I2C bus
1854 * @msgs: One or more messages to execute before STOP is issued to
1855 * terminate the operation; each message begins with a START.
1856 * @num: Number of messages to be executed.
1857 *
1858 * Returns negative errno, else the number of messages executed.
1859 *
1860 * Adapter lock must be held when calling this function. No debug logging
1861 * takes place. adap->algo->master_xfer existence isn't checked.
1862 */
1863int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1864{
1865 unsigned long orig_jiffies;
1866 int ret, try;
1867
1868 if (WARN_ON(!msgs || num < 1))
1869 return -EINVAL;
1870 if (WARN_ON(test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)))
1871 return -ESHUTDOWN;
1872
1873 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1874 return -EOPNOTSUPP;
1875
1876 /*
1877 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1878 * enabled. This is an efficient way of keeping the for-loop from
1879 * being executed when not needed.
1880 */
1881 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1882 int i;
1883 for (i = 0; i < num; i++)
1884 if (msgs[i].flags & I2C_M_RD)
1885 trace_i2c_read(adap, &msgs[i], i);
1886 else
1887 trace_i2c_write(adap, &msgs[i], i);
1888 }
1889
1890 /* Retry automatically on arbitration loss */
1891 orig_jiffies = jiffies;
1892 for (ret = 0, try = 0; try <= adap->retries; try++) {
1893 ret = adap->algo->master_xfer(adap, msgs, num);
1894 if (ret != -EAGAIN)
1895 break;
1896 if (time_after(jiffies, orig_jiffies + adap->timeout))
1897 break;
1898 }
1899
1900 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1901 int i;
1902 for (i = 0; i < ret; i++)
1903 if (msgs[i].flags & I2C_M_RD)
1904 trace_i2c_reply(adap, &msgs[i], i);
1905 trace_i2c_result(adap, num, ret);
1906 }
1907
1908 return ret;
1909}
1910EXPORT_SYMBOL(__i2c_transfer);
1911
1912/**
1913 * i2c_transfer - execute a single or combined I2C message
1914 * @adap: Handle to I2C bus
1915 * @msgs: One or more messages to execute before STOP is issued to
1916 * terminate the operation; each message begins with a START.
1917 * @num: Number of messages to be executed.
1918 *
1919 * Returns negative errno, else the number of messages executed.
1920 *
1921 * Note that there is no requirement that each message be sent to
1922 * the same slave address, although that is the most common model.
1923 */
1924int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1925{
1926 int ret;
1927
1928 if (!adap->algo->master_xfer) {
1929 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1930 return -EOPNOTSUPP;
1931 }
1932
1933 /* REVISIT the fault reporting model here is weak:
1934 *
1935 * - When we get an error after receiving N bytes from a slave,
1936 * there is no way to report "N".
1937 *
1938 * - When we get a NAK after transmitting N bytes to a slave,
1939 * there is no way to report "N" ... or to let the master
1940 * continue executing the rest of this combined message, if
1941 * that's the appropriate response.
1942 *
1943 * - When for example "num" is two and we successfully complete
1944 * the first message but get an error part way through the
1945 * second, it's unclear whether that should be reported as
1946 * one (discarding status on the second message) or errno
1947 * (discarding status on the first one).
1948 */
1949 if (in_atomic() || irqs_disabled()) {
1950 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1951 if (!ret)
1952 /* I2C activity is ongoing. */
1953 return -EAGAIN;
1954 } else {
1955 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1956 }
1957
1958 ret = __i2c_transfer(adap, msgs, num);
1959 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1960
1961 return ret;
1962}
1963EXPORT_SYMBOL(i2c_transfer);
1964
1965/**
1966 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1967 * to/from a buffer
1968 * @client: Handle to slave device
1969 * @buf: Where the data is stored
1970 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1971 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1972 *
1973 * Returns negative errno, or else the number of bytes transferred.
1974 */
1975int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1976 int count, u16 flags)
1977{
1978 int ret;
1979 struct i2c_msg msg = {
1980 .addr = client->addr,
1981 .flags = flags | (client->flags & I2C_M_TEN),
1982 .len = count,
1983 .buf = buf,
1984 };
1985
1986 ret = i2c_transfer(client->adapter, &msg, 1);
1987
1988 /*
1989 * If everything went ok (i.e. 1 msg transferred), return #bytes
1990 * transferred, else error code.
1991 */
1992 return (ret == 1) ? count : ret;
1993}
1994EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1995
1996/**
1997 * i2c_get_device_id - get manufacturer, part id and die revision of a device
1998 * @client: The device to query
1999 * @id: The queried information
2000 *
2001 * Returns negative errno on error, zero on success.
2002 */
2003int i2c_get_device_id(const struct i2c_client *client,
2004 struct i2c_device_identity *id)
2005{
2006 struct i2c_adapter *adap = client->adapter;
2007 union i2c_smbus_data raw_id;
2008 int ret;
2009
2010 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2011 return -EOPNOTSUPP;
2012
2013 raw_id.block[0] = 3;
2014 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2015 I2C_SMBUS_READ, client->addr << 1,
2016 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2017 if (ret)
2018 return ret;
2019
2020 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2021 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2022 id->die_revision = raw_id.block[3] & 0x7;
2023 return 0;
2024}
2025EXPORT_SYMBOL_GPL(i2c_get_device_id);
2026
2027/* ----------------------------------------------------
2028 * the i2c address scanning function
2029 * Will not work for 10-bit addresses!
2030 * ----------------------------------------------------
2031 */
2032
2033/*
2034 * Legacy default probe function, mostly relevant for SMBus. The default
2035 * probe method is a quick write, but it is known to corrupt the 24RF08
2036 * EEPROMs due to a state machine bug, and could also irreversibly
2037 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2038 * we use a short byte read instead. Also, some bus drivers don't implement
2039 * quick write, so we fallback to a byte read in that case too.
2040 * On x86, there is another special case for FSC hardware monitoring chips,
2041 * which want regular byte reads (address 0x73.) Fortunately, these are the
2042 * only known chips using this I2C address on PC hardware.
2043 * Returns 1 if probe succeeded, 0 if not.
2044 */
2045static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2046{
2047 int err;
2048 union i2c_smbus_data dummy;
2049
2050#ifdef CONFIG_X86
2051 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2052 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2053 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2054 I2C_SMBUS_BYTE_DATA, &dummy);
2055 else
2056#endif
2057 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2058 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2059 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2060 I2C_SMBUS_QUICK, NULL);
2061 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2062 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2063 I2C_SMBUS_BYTE, &dummy);
2064 else {
2065 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2066 addr);
2067 err = -EOPNOTSUPP;
2068 }
2069
2070 return err >= 0;
2071}
2072
2073static int i2c_detect_address(struct i2c_client *temp_client,
2074 struct i2c_driver *driver)
2075{
2076 struct i2c_board_info info;
2077 struct i2c_adapter *adapter = temp_client->adapter;
2078 int addr = temp_client->addr;
2079 int err;
2080
2081 /* Make sure the address is valid */
2082 err = i2c_check_7bit_addr_validity_strict(addr);
2083 if (err) {
2084 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2085 addr);
2086 return err;
2087 }
2088
2089 /* Skip if already in use (7 bit, no need to encode flags) */
2090 if (i2c_check_addr_busy(adapter, addr))
2091 return 0;
2092
2093 /* Make sure there is something at this address */
2094 if (!i2c_default_probe(adapter, addr))
2095 return 0;
2096
2097 /* Finally call the custom detection function */
2098 memset(&info, 0, sizeof(struct i2c_board_info));
2099 info.addr = addr;
2100 err = driver->detect(temp_client, &info);
2101 if (err) {
2102 /* -ENODEV is returned if the detection fails. We catch it
2103 here as this isn't an error. */
2104 return err == -ENODEV ? 0 : err;
2105 }
2106
2107 /* Consistency check */
2108 if (info.type[0] == '\0') {
2109 dev_err(&adapter->dev,
2110 "%s detection function provided no name for 0x%x\n",
2111 driver->driver.name, addr);
2112 } else {
2113 struct i2c_client *client;
2114
2115 /* Detection succeeded, instantiate the device */
2116 if (adapter->class & I2C_CLASS_DEPRECATED)
2117 dev_warn(&adapter->dev,
2118 "This adapter will soon drop class based instantiation of devices. "
2119 "Please make sure client 0x%02x gets instantiated by other means. "
2120 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2121 info.addr);
2122
2123 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2124 info.type, info.addr);
2125 client = i2c_new_device(adapter, &info);
2126 if (client)
2127 list_add_tail(&client->detected, &driver->clients);
2128 else
2129 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2130 info.type, info.addr);
2131 }
2132 return 0;
2133}
2134
2135static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2136{
2137 const unsigned short *address_list;
2138 struct i2c_client *temp_client;
2139 int i, err = 0;
2140 int adap_id = i2c_adapter_id(adapter);
2141
2142 address_list = driver->address_list;
2143 if (!driver->detect || !address_list)
2144 return 0;
2145
2146 /* Warn that the adapter lost class based instantiation */
2147 if (adapter->class == I2C_CLASS_DEPRECATED) {
2148 dev_dbg(&adapter->dev,
2149 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2150 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2151 driver->driver.name);
2152 return 0;
2153 }
2154
2155 /* Stop here if the classes do not match */
2156 if (!(adapter->class & driver->class))
2157 return 0;
2158
2159 /* Set up a temporary client to help detect callback */
2160 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2161 if (!temp_client)
2162 return -ENOMEM;
2163 temp_client->adapter = adapter;
2164
2165 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2166 dev_dbg(&adapter->dev,
2167 "found normal entry for adapter %d, addr 0x%02x\n",
2168 adap_id, address_list[i]);
2169 temp_client->addr = address_list[i];
2170 err = i2c_detect_address(temp_client, driver);
2171 if (unlikely(err))
2172 break;
2173 }
2174
2175 kfree(temp_client);
2176 return err;
2177}
2178
2179int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2180{
2181 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2182 I2C_SMBUS_QUICK, NULL) >= 0;
2183}
2184EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2185
2186struct i2c_client *
2187i2c_new_probed_device(struct i2c_adapter *adap,
2188 struct i2c_board_info *info,
2189 unsigned short const *addr_list,
2190 int (*probe)(struct i2c_adapter *, unsigned short addr))
2191{
2192 int i;
2193
2194 if (!probe)
2195 probe = i2c_default_probe;
2196
2197 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2198 /* Check address validity */
2199 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2200 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2201 addr_list[i]);
2202 continue;
2203 }
2204
2205 /* Check address availability (7 bit, no need to encode flags) */
2206 if (i2c_check_addr_busy(adap, addr_list[i])) {
2207 dev_dbg(&adap->dev,
2208 "Address 0x%02x already in use, not probing\n",
2209 addr_list[i]);
2210 continue;
2211 }
2212
2213 /* Test address responsiveness */
2214 if (probe(adap, addr_list[i]))
2215 break;
2216 }
2217
2218 if (addr_list[i] == I2C_CLIENT_END) {
2219 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2220 return NULL;
2221 }
2222
2223 info->addr = addr_list[i];
2224 return i2c_new_device(adap, info);
2225}
2226EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2227
2228struct i2c_adapter *i2c_get_adapter(int nr)
2229{
2230 struct i2c_adapter *adapter;
2231
2232 mutex_lock(&core_lock);
2233 adapter = idr_find(&i2c_adapter_idr, nr);
2234 if (!adapter)
2235 goto exit;
2236
2237 if (try_module_get(adapter->owner))
2238 get_device(&adapter->dev);
2239 else
2240 adapter = NULL;
2241
2242 exit:
2243 mutex_unlock(&core_lock);
2244 return adapter;
2245}
2246EXPORT_SYMBOL(i2c_get_adapter);
2247
2248void i2c_put_adapter(struct i2c_adapter *adap)
2249{
2250 if (!adap)
2251 return;
2252
2253 put_device(&adap->dev);
2254 module_put(adap->owner);
2255}
2256EXPORT_SYMBOL(i2c_put_adapter);
2257
2258/**
2259 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2260 * @msg: the message to be checked
2261 * @threshold: the minimum number of bytes for which using DMA makes sense.
2262 * Should at least be 1.
2263 *
2264 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2265 * Or a valid pointer to be used with DMA. After use, release it by
2266 * calling i2c_put_dma_safe_msg_buf().
2267 *
2268 * This function must only be called from process context!
2269 */
2270u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2271{
2272 /* also skip 0-length msgs for bogus thresholds of 0 */
2273 if (!threshold)
2274 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2275 msg->addr);
2276 if (msg->len < threshold || msg->len == 0)
2277 return NULL;
2278
2279 if (msg->flags & I2C_M_DMA_SAFE)
2280 return msg->buf;
2281
2282 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2283 msg->addr, msg->len);
2284
2285 if (msg->flags & I2C_M_RD)
2286 return kzalloc(msg->len, GFP_KERNEL);
2287 else
2288 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2289}
2290EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2291
2292/**
2293 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2294 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2295 * @msg: the message which the buffer corresponds to
2296 * @xferred: bool saying if the message was transferred
2297 */
2298void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2299{
2300 if (!buf || buf == msg->buf)
2301 return;
2302
2303 if (xferred && msg->flags & I2C_M_RD)
2304 memcpy(msg->buf, buf, msg->len);
2305
2306 kfree(buf);
2307}
2308EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2309
2310MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2311MODULE_DESCRIPTION("I2C-Bus main module");
2312MODULE_LICENSE("GPL");
2313