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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, and attach_adapter calls 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
161/*
162 * We are generating clock pulses. ndelay() determines durating of clk pulses.
163 * We will generate clock with rate 100 KHz and so duration of both clock levels
164 * is: delay in ns = (10^6 / 100) / 2
165 */
166#define RECOVERY_NDELAY 5000
167#define RECOVERY_CLK_CNT 9
168
169int i2c_generic_scl_recovery(struct i2c_adapter *adap)
170{
171 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
172 int i = 0, val = 1, ret = 0;
173
174 if (bri->prepare_recovery)
175 bri->prepare_recovery(adap);
176
177 bri->set_scl(adap, val);
178 if (bri->set_sda)
179 bri->set_sda(adap, 1);
180 ndelay(RECOVERY_NDELAY);
181
182 /*
183 * By this time SCL is high, as we need to give 9 falling-rising edges
184 */
185 while (i++ < RECOVERY_CLK_CNT * 2) {
186 if (val) {
187 /* SCL shouldn't be low here */
188 if (!bri->get_scl(adap)) {
189 dev_err(&adap->dev,
190 "SCL is stuck low, exit recovery\n");
191 ret = -EBUSY;
192 break;
193 }
194 /* Break if SDA is high */
195 if (bri->get_sda && bri->get_sda(adap))
196 break;
197 }
198
199 val = !val;
200 bri->set_scl(adap, val);
201 ndelay(RECOVERY_NDELAY);
202 }
203
204 /* check if recovery actually succeeded */
205 if (bri->get_sda && !bri->get_sda(adap))
206 ret = -EBUSY;
207
208 /* If all went well, send STOP for a sane bus state. */
209 if (ret == 0 && bri->set_sda) {
210 bri->set_scl(adap, 0);
211 ndelay(RECOVERY_NDELAY / 2);
212 bri->set_sda(adap, 0);
213 ndelay(RECOVERY_NDELAY / 2);
214 bri->set_scl(adap, 1);
215 ndelay(RECOVERY_NDELAY / 2);
216 bri->set_sda(adap, 1);
217 ndelay(RECOVERY_NDELAY / 2);
218 }
219
220 if (bri->unprepare_recovery)
221 bri->unprepare_recovery(adap);
222
223 return ret;
224}
225EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
226
227int i2c_recover_bus(struct i2c_adapter *adap)
228{
229 if (!adap->bus_recovery_info)
230 return -EOPNOTSUPP;
231
232 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
233 return adap->bus_recovery_info->recover_bus(adap);
234}
235EXPORT_SYMBOL_GPL(i2c_recover_bus);
236
237static void i2c_init_recovery(struct i2c_adapter *adap)
238{
239 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
240 char *err_str;
241
242 if (!bri)
243 return;
244
245 if (!bri->recover_bus) {
246 err_str = "no recover_bus() found";
247 goto err;
248 }
249
250 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
251 bri->get_scl = get_scl_gpio_value;
252 bri->set_scl = set_scl_gpio_value;
253 if (bri->sda_gpiod) {
254 bri->get_sda = get_sda_gpio_value;
255 /* FIXME: add proper flag instead of '0' once available */
256 if (gpiod_get_direction(bri->sda_gpiod) == 0)
257 bri->set_sda = set_sda_gpio_value;
258 }
259 return;
260 }
261
262 if (bri->recover_bus == i2c_generic_scl_recovery) {
263 /* Generic SCL recovery */
264 if (!bri->set_scl || !bri->get_scl) {
265 err_str = "no {get|set}_scl() found";
266 goto err;
267 }
268 }
269
270 return;
271 err:
272 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
273 adap->bus_recovery_info = NULL;
274}
275
276static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
277{
278 struct i2c_adapter *adap = client->adapter;
279 unsigned int irq;
280
281 if (!adap->host_notify_domain)
282 return -ENXIO;
283
284 if (client->flags & I2C_CLIENT_TEN)
285 return -EINVAL;
286
287 irq = irq_find_mapping(adap->host_notify_domain, client->addr);
288 if (!irq)
289 irq = irq_create_mapping(adap->host_notify_domain,
290 client->addr);
291
292 return irq > 0 ? irq : -ENXIO;
293}
294
295static int i2c_device_probe(struct device *dev)
296{
297 struct i2c_client *client = i2c_verify_client(dev);
298 struct i2c_driver *driver;
299 int status;
300
301 if (!client)
302 return 0;
303
304 driver = to_i2c_driver(dev->driver);
305
306 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
307 int irq = -ENOENT;
308
309 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
310 dev_dbg(dev, "Using Host Notify IRQ\n");
311 irq = i2c_smbus_host_notify_to_irq(client);
312 } else if (dev->of_node) {
313 irq = of_irq_get_byname(dev->of_node, "irq");
314 if (irq == -EINVAL || irq == -ENODATA)
315 irq = of_irq_get(dev->of_node, 0);
316 } else if (ACPI_COMPANION(dev)) {
317 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
318 }
319 if (irq == -EPROBE_DEFER)
320 return irq;
321
322 if (irq < 0)
323 irq = 0;
324
325 client->irq = irq;
326 }
327
328 /*
329 * An I2C ID table is not mandatory, if and only if, a suitable OF
330 * or ACPI ID table is supplied for the probing device.
331 */
332 if (!driver->id_table &&
333 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
334 !i2c_of_match_device(dev->driver->of_match_table, client))
335 return -ENODEV;
336
337 if (client->flags & I2C_CLIENT_WAKE) {
338 int wakeirq = -ENOENT;
339
340 if (dev->of_node) {
341 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
342 if (wakeirq == -EPROBE_DEFER)
343 return wakeirq;
344 }
345
346 device_init_wakeup(&client->dev, true);
347
348 if (wakeirq > 0 && wakeirq != client->irq)
349 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
350 else if (client->irq > 0)
351 status = dev_pm_set_wake_irq(dev, client->irq);
352 else
353 status = 0;
354
355 if (status)
356 dev_warn(&client->dev, "failed to set up wakeup irq\n");
357 }
358
359 dev_dbg(dev, "probe\n");
360
361 status = of_clk_set_defaults(dev->of_node, false);
362 if (status < 0)
363 goto err_clear_wakeup_irq;
364
365 status = dev_pm_domain_attach(&client->dev, true);
366 if (status == -EPROBE_DEFER)
367 goto err_clear_wakeup_irq;
368
369 /*
370 * When there are no more users of probe(),
371 * rename probe_new to probe.
372 */
373 if (driver->probe_new)
374 status = driver->probe_new(client);
375 else if (driver->probe)
376 status = driver->probe(client,
377 i2c_match_id(driver->id_table, client));
378 else
379 status = -EINVAL;
380
381 if (status)
382 goto err_detach_pm_domain;
383
384 return 0;
385
386err_detach_pm_domain:
387 dev_pm_domain_detach(&client->dev, true);
388err_clear_wakeup_irq:
389 dev_pm_clear_wake_irq(&client->dev);
390 device_init_wakeup(&client->dev, false);
391 return status;
392}
393
394static int i2c_device_remove(struct device *dev)
395{
396 struct i2c_client *client = i2c_verify_client(dev);
397 struct i2c_driver *driver;
398 int status = 0;
399
400 if (!client || !dev->driver)
401 return 0;
402
403 driver = to_i2c_driver(dev->driver);
404 if (driver->remove) {
405 dev_dbg(dev, "remove\n");
406 status = driver->remove(client);
407 }
408
409 dev_pm_domain_detach(&client->dev, true);
410
411 dev_pm_clear_wake_irq(&client->dev);
412 device_init_wakeup(&client->dev, false);
413
414 return status;
415}
416
417static void i2c_device_shutdown(struct device *dev)
418{
419 struct i2c_client *client = i2c_verify_client(dev);
420 struct i2c_driver *driver;
421
422 if (!client || !dev->driver)
423 return;
424 driver = to_i2c_driver(dev->driver);
425 if (driver->shutdown)
426 driver->shutdown(client);
427}
428
429static void i2c_client_dev_release(struct device *dev)
430{
431 kfree(to_i2c_client(dev));
432}
433
434static ssize_t
435show_name(struct device *dev, struct device_attribute *attr, char *buf)
436{
437 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
438 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
439}
440static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
441
442static ssize_t
443show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
444{
445 struct i2c_client *client = to_i2c_client(dev);
446 int len;
447
448 len = of_device_modalias(dev, buf, PAGE_SIZE);
449 if (len != -ENODEV)
450 return len;
451
452 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
453 if (len != -ENODEV)
454 return len;
455
456 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
457}
458static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
459
460static struct attribute *i2c_dev_attrs[] = {
461 &dev_attr_name.attr,
462 /* modalias helps coldplug: modprobe $(cat .../modalias) */
463 &dev_attr_modalias.attr,
464 NULL
465};
466ATTRIBUTE_GROUPS(i2c_dev);
467
468struct bus_type i2c_bus_type = {
469 .name = "i2c",
470 .match = i2c_device_match,
471 .probe = i2c_device_probe,
472 .remove = i2c_device_remove,
473 .shutdown = i2c_device_shutdown,
474};
475EXPORT_SYMBOL_GPL(i2c_bus_type);
476
477struct device_type i2c_client_type = {
478 .groups = i2c_dev_groups,
479 .uevent = i2c_device_uevent,
480 .release = i2c_client_dev_release,
481};
482EXPORT_SYMBOL_GPL(i2c_client_type);
483
484
485/**
486 * i2c_verify_client - return parameter as i2c_client, or NULL
487 * @dev: device, probably from some driver model iterator
488 *
489 * When traversing the driver model tree, perhaps using driver model
490 * iterators like @device_for_each_child(), you can't assume very much
491 * about the nodes you find. Use this function to avoid oopses caused
492 * by wrongly treating some non-I2C device as an i2c_client.
493 */
494struct i2c_client *i2c_verify_client(struct device *dev)
495{
496 return (dev->type == &i2c_client_type)
497 ? to_i2c_client(dev)
498 : NULL;
499}
500EXPORT_SYMBOL(i2c_verify_client);
501
502
503/* Return a unique address which takes the flags of the client into account */
504static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
505{
506 unsigned short addr = client->addr;
507
508 /* For some client flags, add an arbitrary offset to avoid collisions */
509 if (client->flags & I2C_CLIENT_TEN)
510 addr |= I2C_ADDR_OFFSET_TEN_BIT;
511
512 if (client->flags & I2C_CLIENT_SLAVE)
513 addr |= I2C_ADDR_OFFSET_SLAVE;
514
515 return addr;
516}
517
518/* This is a permissive address validity check, I2C address map constraints
519 * are purposely not enforced, except for the general call address. */
520static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
521{
522 if (flags & I2C_CLIENT_TEN) {
523 /* 10-bit address, all values are valid */
524 if (addr > 0x3ff)
525 return -EINVAL;
526 } else {
527 /* 7-bit address, reject the general call address */
528 if (addr == 0x00 || addr > 0x7f)
529 return -EINVAL;
530 }
531 return 0;
532}
533
534/* And this is a strict address validity check, used when probing. If a
535 * device uses a reserved address, then it shouldn't be probed. 7-bit
536 * addressing is assumed, 10-bit address devices are rare and should be
537 * explicitly enumerated. */
538int i2c_check_7bit_addr_validity_strict(unsigned short addr)
539{
540 /*
541 * Reserved addresses per I2C specification:
542 * 0x00 General call address / START byte
543 * 0x01 CBUS address
544 * 0x02 Reserved for different bus format
545 * 0x03 Reserved for future purposes
546 * 0x04-0x07 Hs-mode master code
547 * 0x78-0x7b 10-bit slave addressing
548 * 0x7c-0x7f Reserved for future purposes
549 */
550 if (addr < 0x08 || addr > 0x77)
551 return -EINVAL;
552 return 0;
553}
554
555static int __i2c_check_addr_busy(struct device *dev, void *addrp)
556{
557 struct i2c_client *client = i2c_verify_client(dev);
558 int addr = *(int *)addrp;
559
560 if (client && i2c_encode_flags_to_addr(client) == addr)
561 return -EBUSY;
562 return 0;
563}
564
565/* walk up mux tree */
566static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
567{
568 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
569 int result;
570
571 result = device_for_each_child(&adapter->dev, &addr,
572 __i2c_check_addr_busy);
573
574 if (!result && parent)
575 result = i2c_check_mux_parents(parent, addr);
576
577 return result;
578}
579
580/* recurse down mux tree */
581static int i2c_check_mux_children(struct device *dev, void *addrp)
582{
583 int result;
584
585 if (dev->type == &i2c_adapter_type)
586 result = device_for_each_child(dev, addrp,
587 i2c_check_mux_children);
588 else
589 result = __i2c_check_addr_busy(dev, addrp);
590
591 return result;
592}
593
594static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
595{
596 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
597 int result = 0;
598
599 if (parent)
600 result = i2c_check_mux_parents(parent, addr);
601
602 if (!result)
603 result = device_for_each_child(&adapter->dev, &addr,
604 i2c_check_mux_children);
605
606 return result;
607}
608
609/**
610 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
611 * @adapter: Target I2C bus segment
612 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
613 * locks only this branch in the adapter tree
614 */
615static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
616 unsigned int flags)
617{
618 rt_mutex_lock(&adapter->bus_lock);
619}
620
621/**
622 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
623 * @adapter: Target I2C bus segment
624 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
625 * trylocks only this branch in the adapter tree
626 */
627static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
628 unsigned int flags)
629{
630 return rt_mutex_trylock(&adapter->bus_lock);
631}
632
633/**
634 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
635 * @adapter: Target I2C bus segment
636 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
637 * unlocks only this branch in the adapter tree
638 */
639static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
640 unsigned int flags)
641{
642 rt_mutex_unlock(&adapter->bus_lock);
643}
644
645static void i2c_dev_set_name(struct i2c_adapter *adap,
646 struct i2c_client *client,
647 struct i2c_board_info const *info)
648{
649 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
650
651 if (info && info->dev_name) {
652 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
653 return;
654 }
655
656 if (adev) {
657 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
658 return;
659 }
660
661 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
662 i2c_encode_flags_to_addr(client));
663}
664
665static int i2c_dev_irq_from_resources(const struct resource *resources,
666 unsigned int num_resources)
667{
668 struct irq_data *irqd;
669 int i;
670
671 for (i = 0; i < num_resources; i++) {
672 const struct resource *r = &resources[i];
673
674 if (resource_type(r) != IORESOURCE_IRQ)
675 continue;
676
677 if (r->flags & IORESOURCE_BITS) {
678 irqd = irq_get_irq_data(r->start);
679 if (!irqd)
680 break;
681
682 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
683 }
684
685 return r->start;
686 }
687
688 return 0;
689}
690
691/**
692 * i2c_new_device - instantiate an i2c device
693 * @adap: the adapter managing the device
694 * @info: describes one I2C device; bus_num is ignored
695 * Context: can sleep
696 *
697 * Create an i2c device. Binding is handled through driver model
698 * probe()/remove() methods. A driver may be bound to this device when we
699 * return from this function, or any later moment (e.g. maybe hotplugging will
700 * load the driver module). This call is not appropriate for use by mainboard
701 * initialization logic, which usually runs during an arch_initcall() long
702 * before any i2c_adapter could exist.
703 *
704 * This returns the new i2c client, which may be saved for later use with
705 * i2c_unregister_device(); or NULL to indicate an error.
706 */
707struct i2c_client *
708i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
709{
710 struct i2c_client *client;
711 int status;
712
713 client = kzalloc(sizeof *client, GFP_KERNEL);
714 if (!client)
715 return NULL;
716
717 client->adapter = adap;
718
719 client->dev.platform_data = info->platform_data;
720
721 if (info->archdata)
722 client->dev.archdata = *info->archdata;
723
724 client->flags = info->flags;
725 client->addr = info->addr;
726
727 client->irq = info->irq;
728 if (!client->irq)
729 client->irq = i2c_dev_irq_from_resources(info->resources,
730 info->num_resources);
731
732 strlcpy(client->name, info->type, sizeof(client->name));
733
734 status = i2c_check_addr_validity(client->addr, client->flags);
735 if (status) {
736 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
737 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
738 goto out_err_silent;
739 }
740
741 /* Check for address business */
742 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
743 if (status)
744 goto out_err;
745
746 client->dev.parent = &client->adapter->dev;
747 client->dev.bus = &i2c_bus_type;
748 client->dev.type = &i2c_client_type;
749 client->dev.of_node = info->of_node;
750 client->dev.fwnode = info->fwnode;
751
752 i2c_dev_set_name(adap, client, info);
753
754 if (info->properties) {
755 status = device_add_properties(&client->dev, info->properties);
756 if (status) {
757 dev_err(&adap->dev,
758 "Failed to add properties to client %s: %d\n",
759 client->name, status);
760 goto out_err;
761 }
762 }
763
764 status = device_register(&client->dev);
765 if (status)
766 goto out_free_props;
767
768 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
769 client->name, dev_name(&client->dev));
770
771 return client;
772
773out_free_props:
774 if (info->properties)
775 device_remove_properties(&client->dev);
776out_err:
777 dev_err(&adap->dev,
778 "Failed to register i2c client %s at 0x%02x (%d)\n",
779 client->name, client->addr, status);
780out_err_silent:
781 kfree(client);
782 return NULL;
783}
784EXPORT_SYMBOL_GPL(i2c_new_device);
785
786
787/**
788 * i2c_unregister_device - reverse effect of i2c_new_device()
789 * @client: value returned from i2c_new_device()
790 * Context: can sleep
791 */
792void i2c_unregister_device(struct i2c_client *client)
793{
794 if (!client)
795 return;
796
797 if (client->dev.of_node) {
798 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
799 of_node_put(client->dev.of_node);
800 }
801
802 if (ACPI_COMPANION(&client->dev))
803 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
804 device_unregister(&client->dev);
805}
806EXPORT_SYMBOL_GPL(i2c_unregister_device);
807
808
809static const struct i2c_device_id dummy_id[] = {
810 { "dummy", 0 },
811 { },
812};
813
814static int dummy_probe(struct i2c_client *client,
815 const struct i2c_device_id *id)
816{
817 return 0;
818}
819
820static int dummy_remove(struct i2c_client *client)
821{
822 return 0;
823}
824
825static struct i2c_driver dummy_driver = {
826 .driver.name = "dummy",
827 .probe = dummy_probe,
828 .remove = dummy_remove,
829 .id_table = dummy_id,
830};
831
832/**
833 * i2c_new_dummy - return a new i2c device bound to a dummy driver
834 * @adapter: the adapter managing the device
835 * @address: seven bit address to be used
836 * Context: can sleep
837 *
838 * This returns an I2C client bound to the "dummy" driver, intended for use
839 * with devices that consume multiple addresses. Examples of such chips
840 * include various EEPROMS (like 24c04 and 24c08 models).
841 *
842 * These dummy devices have two main uses. First, most I2C and SMBus calls
843 * except i2c_transfer() need a client handle; the dummy will be that handle.
844 * And second, this prevents the specified address from being bound to a
845 * different driver.
846 *
847 * This returns the new i2c client, which should be saved for later use with
848 * i2c_unregister_device(); or NULL to indicate an error.
849 */
850struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
851{
852 struct i2c_board_info info = {
853 I2C_BOARD_INFO("dummy", address),
854 };
855
856 return i2c_new_device(adapter, &info);
857}
858EXPORT_SYMBOL_GPL(i2c_new_dummy);
859
860/**
861 * i2c_new_secondary_device - Helper to get the instantiated secondary address
862 * and create the associated device
863 * @client: Handle to the primary client
864 * @name: Handle to specify which secondary address to get
865 * @default_addr: Used as a fallback if no secondary address was specified
866 * Context: can sleep
867 *
868 * I2C clients can be composed of multiple I2C slaves bound together in a single
869 * component. The I2C client driver then binds to the master I2C slave and needs
870 * to create I2C dummy clients to communicate with all the other slaves.
871 *
872 * This function creates and returns an I2C dummy client whose I2C address is
873 * retrieved from the platform firmware based on the given slave name. If no
874 * address is specified by the firmware default_addr is used.
875 *
876 * On DT-based platforms the address is retrieved from the "reg" property entry
877 * cell whose "reg-names" value matches the slave name.
878 *
879 * This returns the new i2c client, which should be saved for later use with
880 * i2c_unregister_device(); or NULL to indicate an error.
881 */
882struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
883 const char *name,
884 u16 default_addr)
885{
886 struct device_node *np = client->dev.of_node;
887 u32 addr = default_addr;
888 int i;
889
890 if (np) {
891 i = of_property_match_string(np, "reg-names", name);
892 if (i >= 0)
893 of_property_read_u32_index(np, "reg", i, &addr);
894 }
895
896 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
897 return i2c_new_dummy(client->adapter, addr);
898}
899EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
900
901/* ------------------------------------------------------------------------- */
902
903/* I2C bus adapters -- one roots each I2C or SMBUS segment */
904
905static void i2c_adapter_dev_release(struct device *dev)
906{
907 struct i2c_adapter *adap = to_i2c_adapter(dev);
908 complete(&adap->dev_released);
909}
910
911unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
912{
913 unsigned int depth = 0;
914
915 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
916 depth++;
917
918 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
919 "adapter depth exceeds lockdep subclass limit\n");
920
921 return depth;
922}
923EXPORT_SYMBOL_GPL(i2c_adapter_depth);
924
925/*
926 * Let users instantiate I2C devices through sysfs. This can be used when
927 * platform initialization code doesn't contain the proper data for
928 * whatever reason. Also useful for drivers that do device detection and
929 * detection fails, either because the device uses an unexpected address,
930 * or this is a compatible device with different ID register values.
931 *
932 * Parameter checking may look overzealous, but we really don't want
933 * the user to provide incorrect parameters.
934 */
935static ssize_t
936i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
937 const char *buf, size_t count)
938{
939 struct i2c_adapter *adap = to_i2c_adapter(dev);
940 struct i2c_board_info info;
941 struct i2c_client *client;
942 char *blank, end;
943 int res;
944
945 memset(&info, 0, sizeof(struct i2c_board_info));
946
947 blank = strchr(buf, ' ');
948 if (!blank) {
949 dev_err(dev, "%s: Missing parameters\n", "new_device");
950 return -EINVAL;
951 }
952 if (blank - buf > I2C_NAME_SIZE - 1) {
953 dev_err(dev, "%s: Invalid device name\n", "new_device");
954 return -EINVAL;
955 }
956 memcpy(info.type, buf, blank - buf);
957
958 /* Parse remaining parameters, reject extra parameters */
959 res = sscanf(++blank, "%hi%c", &info.addr, &end);
960 if (res < 1) {
961 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
962 return -EINVAL;
963 }
964 if (res > 1 && end != '\n') {
965 dev_err(dev, "%s: Extra parameters\n", "new_device");
966 return -EINVAL;
967 }
968
969 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
970 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
971 info.flags |= I2C_CLIENT_TEN;
972 }
973
974 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
975 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
976 info.flags |= I2C_CLIENT_SLAVE;
977 }
978
979 client = i2c_new_device(adap, &info);
980 if (!client)
981 return -EINVAL;
982
983 /* Keep track of the added device */
984 mutex_lock(&adap->userspace_clients_lock);
985 list_add_tail(&client->detected, &adap->userspace_clients);
986 mutex_unlock(&adap->userspace_clients_lock);
987 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
988 info.type, info.addr);
989
990 return count;
991}
992static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
993
994/*
995 * And of course let the users delete the devices they instantiated, if
996 * they got it wrong. This interface can only be used to delete devices
997 * instantiated by i2c_sysfs_new_device above. This guarantees that we
998 * don't delete devices to which some kernel code still has references.
999 *
1000 * Parameter checking may look overzealous, but we really don't want
1001 * the user to delete the wrong device.
1002 */
1003static ssize_t
1004i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1005 const char *buf, size_t count)
1006{
1007 struct i2c_adapter *adap = to_i2c_adapter(dev);
1008 struct i2c_client *client, *next;
1009 unsigned short addr;
1010 char end;
1011 int res;
1012
1013 /* Parse parameters, reject extra parameters */
1014 res = sscanf(buf, "%hi%c", &addr, &end);
1015 if (res < 1) {
1016 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1017 return -EINVAL;
1018 }
1019 if (res > 1 && end != '\n') {
1020 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1021 return -EINVAL;
1022 }
1023
1024 /* Make sure the device was added through sysfs */
1025 res = -ENOENT;
1026 mutex_lock_nested(&adap->userspace_clients_lock,
1027 i2c_adapter_depth(adap));
1028 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1029 detected) {
1030 if (i2c_encode_flags_to_addr(client) == addr) {
1031 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1032 "delete_device", client->name, client->addr);
1033
1034 list_del(&client->detected);
1035 i2c_unregister_device(client);
1036 res = count;
1037 break;
1038 }
1039 }
1040 mutex_unlock(&adap->userspace_clients_lock);
1041
1042 if (res < 0)
1043 dev_err(dev, "%s: Can't find device in list\n",
1044 "delete_device");
1045 return res;
1046}
1047static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1048 i2c_sysfs_delete_device);
1049
1050static struct attribute *i2c_adapter_attrs[] = {
1051 &dev_attr_name.attr,
1052 &dev_attr_new_device.attr,
1053 &dev_attr_delete_device.attr,
1054 NULL
1055};
1056ATTRIBUTE_GROUPS(i2c_adapter);
1057
1058struct device_type i2c_adapter_type = {
1059 .groups = i2c_adapter_groups,
1060 .release = i2c_adapter_dev_release,
1061};
1062EXPORT_SYMBOL_GPL(i2c_adapter_type);
1063
1064/**
1065 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1066 * @dev: device, probably from some driver model iterator
1067 *
1068 * When traversing the driver model tree, perhaps using driver model
1069 * iterators like @device_for_each_child(), you can't assume very much
1070 * about the nodes you find. Use this function to avoid oopses caused
1071 * by wrongly treating some non-I2C device as an i2c_adapter.
1072 */
1073struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1074{
1075 return (dev->type == &i2c_adapter_type)
1076 ? to_i2c_adapter(dev)
1077 : NULL;
1078}
1079EXPORT_SYMBOL(i2c_verify_adapter);
1080
1081#ifdef CONFIG_I2C_COMPAT
1082static struct class_compat *i2c_adapter_compat_class;
1083#endif
1084
1085static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1086{
1087 struct i2c_devinfo *devinfo;
1088
1089 down_read(&__i2c_board_lock);
1090 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1091 if (devinfo->busnum == adapter->nr
1092 && !i2c_new_device(adapter,
1093 &devinfo->board_info))
1094 dev_err(&adapter->dev,
1095 "Can't create device at 0x%02x\n",
1096 devinfo->board_info.addr);
1097 }
1098 up_read(&__i2c_board_lock);
1099}
1100
1101static int i2c_do_add_adapter(struct i2c_driver *driver,
1102 struct i2c_adapter *adap)
1103{
1104 /* Detect supported devices on that bus, and instantiate them */
1105 i2c_detect(adap, driver);
1106
1107 /* Let legacy drivers scan this bus for matching devices */
1108 if (driver->attach_adapter) {
1109 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1110 driver->driver.name);
1111 dev_warn(&adap->dev,
1112 "Please use another way to instantiate your i2c_client\n");
1113 /* We ignore the return code; if it fails, too bad */
1114 driver->attach_adapter(adap);
1115 }
1116 return 0;
1117}
1118
1119static int __process_new_adapter(struct device_driver *d, void *data)
1120{
1121 return i2c_do_add_adapter(to_i2c_driver(d), data);
1122}
1123
1124static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1125 .lock_bus = i2c_adapter_lock_bus,
1126 .trylock_bus = i2c_adapter_trylock_bus,
1127 .unlock_bus = i2c_adapter_unlock_bus,
1128};
1129
1130static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1131{
1132 struct irq_domain *domain = adap->host_notify_domain;
1133 irq_hw_number_t hwirq;
1134
1135 if (!domain)
1136 return;
1137
1138 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1139 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1140
1141 irq_domain_remove(domain);
1142 adap->host_notify_domain = NULL;
1143}
1144
1145static int i2c_host_notify_irq_map(struct irq_domain *h,
1146 unsigned int virq,
1147 irq_hw_number_t hw_irq_num)
1148{
1149 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1150
1151 return 0;
1152}
1153
1154static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1155 .map = i2c_host_notify_irq_map,
1156};
1157
1158static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1159{
1160 struct irq_domain *domain;
1161
1162 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1163 return 0;
1164
1165 domain = irq_domain_create_linear(adap->dev.fwnode,
1166 I2C_ADDR_7BITS_COUNT,
1167 &i2c_host_notify_irq_ops, adap);
1168 if (!domain)
1169 return -ENOMEM;
1170
1171 adap->host_notify_domain = domain;
1172
1173 return 0;
1174}
1175
1176/**
1177 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1178 * I2C client.
1179 * @adap: the adapter
1180 * @addr: the I2C address of the notifying device
1181 * Context: can't sleep
1182 *
1183 * Helper function to be called from an I2C bus driver's interrupt
1184 * handler. It will schedule the Host Notify IRQ.
1185 */
1186int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1187{
1188 int irq;
1189
1190 if (!adap)
1191 return -EINVAL;
1192
1193 irq = irq_find_mapping(adap->host_notify_domain, addr);
1194 if (irq <= 0)
1195 return -ENXIO;
1196
1197 generic_handle_irq(irq);
1198
1199 return 0;
1200}
1201EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1202
1203static int i2c_register_adapter(struct i2c_adapter *adap)
1204{
1205 int res = -EINVAL;
1206
1207 /* Can't register until after driver model init */
1208 if (WARN_ON(!is_registered)) {
1209 res = -EAGAIN;
1210 goto out_list;
1211 }
1212
1213 /* Sanity checks */
1214 if (WARN(!adap->name[0], "i2c adapter has no name"))
1215 goto out_list;
1216
1217 if (!adap->algo) {
1218 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1219 goto out_list;
1220 }
1221
1222 if (!adap->lock_ops)
1223 adap->lock_ops = &i2c_adapter_lock_ops;
1224
1225 rt_mutex_init(&adap->bus_lock);
1226 rt_mutex_init(&adap->mux_lock);
1227 mutex_init(&adap->userspace_clients_lock);
1228 INIT_LIST_HEAD(&adap->userspace_clients);
1229
1230 /* Set default timeout to 1 second if not already set */
1231 if (adap->timeout == 0)
1232 adap->timeout = HZ;
1233
1234 /* register soft irqs for Host Notify */
1235 res = i2c_setup_host_notify_irq_domain(adap);
1236 if (res) {
1237 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1238 adap->name, res);
1239 goto out_list;
1240 }
1241
1242 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1243 adap->dev.bus = &i2c_bus_type;
1244 adap->dev.type = &i2c_adapter_type;
1245 res = device_register(&adap->dev);
1246 if (res) {
1247 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1248 goto out_list;
1249 }
1250
1251 res = of_i2c_setup_smbus_alert(adap);
1252 if (res)
1253 goto out_reg;
1254
1255 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1256
1257 pm_runtime_no_callbacks(&adap->dev);
1258 pm_suspend_ignore_children(&adap->dev, true);
1259 pm_runtime_enable(&adap->dev);
1260
1261#ifdef CONFIG_I2C_COMPAT
1262 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1263 adap->dev.parent);
1264 if (res)
1265 dev_warn(&adap->dev,
1266 "Failed to create compatibility class link\n");
1267#endif
1268
1269 i2c_init_recovery(adap);
1270
1271 /* create pre-declared device nodes */
1272 of_i2c_register_devices(adap);
1273 i2c_acpi_register_devices(adap);
1274 i2c_acpi_install_space_handler(adap);
1275
1276 if (adap->nr < __i2c_first_dynamic_bus_num)
1277 i2c_scan_static_board_info(adap);
1278
1279 /* Notify drivers */
1280 mutex_lock(&core_lock);
1281 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1282 mutex_unlock(&core_lock);
1283
1284 return 0;
1285
1286out_reg:
1287 init_completion(&adap->dev_released);
1288 device_unregister(&adap->dev);
1289 wait_for_completion(&adap->dev_released);
1290out_list:
1291 mutex_lock(&core_lock);
1292 idr_remove(&i2c_adapter_idr, adap->nr);
1293 mutex_unlock(&core_lock);
1294 return res;
1295}
1296
1297/**
1298 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1299 * @adap: the adapter to register (with adap->nr initialized)
1300 * Context: can sleep
1301 *
1302 * See i2c_add_numbered_adapter() for details.
1303 */
1304static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1305{
1306 int id;
1307
1308 mutex_lock(&core_lock);
1309 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1310 mutex_unlock(&core_lock);
1311 if (WARN(id < 0, "couldn't get idr"))
1312 return id == -ENOSPC ? -EBUSY : id;
1313
1314 return i2c_register_adapter(adap);
1315}
1316
1317/**
1318 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1319 * @adapter: the adapter to add
1320 * Context: can sleep
1321 *
1322 * This routine is used to declare an I2C adapter when its bus number
1323 * doesn't matter or when its bus number is specified by an dt alias.
1324 * Examples of bases when the bus number doesn't matter: I2C adapters
1325 * dynamically added by USB links or PCI plugin cards.
1326 *
1327 * When this returns zero, a new bus number was allocated and stored
1328 * in adap->nr, and the specified adapter became available for clients.
1329 * Otherwise, a negative errno value is returned.
1330 */
1331int i2c_add_adapter(struct i2c_adapter *adapter)
1332{
1333 struct device *dev = &adapter->dev;
1334 int id;
1335
1336 if (dev->of_node) {
1337 id = of_alias_get_id(dev->of_node, "i2c");
1338 if (id >= 0) {
1339 adapter->nr = id;
1340 return __i2c_add_numbered_adapter(adapter);
1341 }
1342 }
1343
1344 mutex_lock(&core_lock);
1345 id = idr_alloc(&i2c_adapter_idr, adapter,
1346 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1347 mutex_unlock(&core_lock);
1348 if (WARN(id < 0, "couldn't get idr"))
1349 return id;
1350
1351 adapter->nr = id;
1352
1353 return i2c_register_adapter(adapter);
1354}
1355EXPORT_SYMBOL(i2c_add_adapter);
1356
1357/**
1358 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1359 * @adap: the adapter to register (with adap->nr initialized)
1360 * Context: can sleep
1361 *
1362 * This routine is used to declare an I2C adapter when its bus number
1363 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1364 * or otherwise built in to the system's mainboard, and where i2c_board_info
1365 * is used to properly configure I2C devices.
1366 *
1367 * If the requested bus number is set to -1, then this function will behave
1368 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1369 *
1370 * If no devices have pre-been declared for this bus, then be sure to
1371 * register the adapter before any dynamically allocated ones. Otherwise
1372 * the required bus ID may not be available.
1373 *
1374 * When this returns zero, the specified adapter became available for
1375 * clients using the bus number provided in adap->nr. Also, the table
1376 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1377 * and the appropriate driver model device nodes are created. Otherwise, a
1378 * negative errno value is returned.
1379 */
1380int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1381{
1382 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1383 return i2c_add_adapter(adap);
1384
1385 return __i2c_add_numbered_adapter(adap);
1386}
1387EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1388
1389static void i2c_do_del_adapter(struct i2c_driver *driver,
1390 struct i2c_adapter *adapter)
1391{
1392 struct i2c_client *client, *_n;
1393
1394 /* Remove the devices we created ourselves as the result of hardware
1395 * probing (using a driver's detect method) */
1396 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1397 if (client->adapter == adapter) {
1398 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1399 client->name, client->addr);
1400 list_del(&client->detected);
1401 i2c_unregister_device(client);
1402 }
1403 }
1404}
1405
1406static int __unregister_client(struct device *dev, void *dummy)
1407{
1408 struct i2c_client *client = i2c_verify_client(dev);
1409 if (client && strcmp(client->name, "dummy"))
1410 i2c_unregister_device(client);
1411 return 0;
1412}
1413
1414static int __unregister_dummy(struct device *dev, void *dummy)
1415{
1416 struct i2c_client *client = i2c_verify_client(dev);
1417 i2c_unregister_device(client);
1418 return 0;
1419}
1420
1421static int __process_removed_adapter(struct device_driver *d, void *data)
1422{
1423 i2c_do_del_adapter(to_i2c_driver(d), data);
1424 return 0;
1425}
1426
1427/**
1428 * i2c_del_adapter - unregister I2C adapter
1429 * @adap: the adapter being unregistered
1430 * Context: can sleep
1431 *
1432 * This unregisters an I2C adapter which was previously registered
1433 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1434 */
1435void i2c_del_adapter(struct i2c_adapter *adap)
1436{
1437 struct i2c_adapter *found;
1438 struct i2c_client *client, *next;
1439
1440 /* First make sure that this adapter was ever added */
1441 mutex_lock(&core_lock);
1442 found = idr_find(&i2c_adapter_idr, adap->nr);
1443 mutex_unlock(&core_lock);
1444 if (found != adap) {
1445 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1446 return;
1447 }
1448
1449 i2c_acpi_remove_space_handler(adap);
1450 /* Tell drivers about this removal */
1451 mutex_lock(&core_lock);
1452 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1453 __process_removed_adapter);
1454 mutex_unlock(&core_lock);
1455
1456 /* Remove devices instantiated from sysfs */
1457 mutex_lock_nested(&adap->userspace_clients_lock,
1458 i2c_adapter_depth(adap));
1459 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1460 detected) {
1461 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1462 client->addr);
1463 list_del(&client->detected);
1464 i2c_unregister_device(client);
1465 }
1466 mutex_unlock(&adap->userspace_clients_lock);
1467
1468 /* Detach any active clients. This can't fail, thus we do not
1469 * check the returned value. This is a two-pass process, because
1470 * we can't remove the dummy devices during the first pass: they
1471 * could have been instantiated by real devices wishing to clean
1472 * them up properly, so we give them a chance to do that first. */
1473 device_for_each_child(&adap->dev, NULL, __unregister_client);
1474 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1475
1476#ifdef CONFIG_I2C_COMPAT
1477 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1478 adap->dev.parent);
1479#endif
1480
1481 /* device name is gone after device_unregister */
1482 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1483
1484 pm_runtime_disable(&adap->dev);
1485
1486 i2c_host_notify_irq_teardown(adap);
1487
1488 /* wait until all references to the device are gone
1489 *
1490 * FIXME: This is old code and should ideally be replaced by an
1491 * alternative which results in decoupling the lifetime of the struct
1492 * device from the i2c_adapter, like spi or netdev do. Any solution
1493 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1494 */
1495 init_completion(&adap->dev_released);
1496 device_unregister(&adap->dev);
1497 wait_for_completion(&adap->dev_released);
1498
1499 /* free bus id */
1500 mutex_lock(&core_lock);
1501 idr_remove(&i2c_adapter_idr, adap->nr);
1502 mutex_unlock(&core_lock);
1503
1504 /* Clear the device structure in case this adapter is ever going to be
1505 added again */
1506 memset(&adap->dev, 0, sizeof(adap->dev));
1507}
1508EXPORT_SYMBOL(i2c_del_adapter);
1509
1510/**
1511 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1512 * @dev: The device to scan for I2C timing properties
1513 * @t: the i2c_timings struct to be filled with values
1514 * @use_defaults: bool to use sane defaults derived from the I2C specification
1515 * when properties are not found, otherwise use 0
1516 *
1517 * Scan the device for the generic I2C properties describing timing parameters
1518 * for the signal and fill the given struct with the results. If a property was
1519 * not found and use_defaults was true, then maximum timings are assumed which
1520 * are derived from the I2C specification. If use_defaults is not used, the
1521 * results will be 0, so drivers can apply their own defaults later. The latter
1522 * is mainly intended for avoiding regressions of existing drivers which want
1523 * to switch to this function. New drivers almost always should use the defaults.
1524 */
1525
1526void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1527{
1528 int ret;
1529
1530 memset(t, 0, sizeof(*t));
1531
1532 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1533 if (ret && use_defaults)
1534 t->bus_freq_hz = 100000;
1535
1536 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1537 if (ret && use_defaults) {
1538 if (t->bus_freq_hz <= 100000)
1539 t->scl_rise_ns = 1000;
1540 else if (t->bus_freq_hz <= 400000)
1541 t->scl_rise_ns = 300;
1542 else
1543 t->scl_rise_ns = 120;
1544 }
1545
1546 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1547 if (ret && use_defaults) {
1548 if (t->bus_freq_hz <= 400000)
1549 t->scl_fall_ns = 300;
1550 else
1551 t->scl_fall_ns = 120;
1552 }
1553
1554 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1555
1556 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1557 if (ret && use_defaults)
1558 t->sda_fall_ns = t->scl_fall_ns;
1559}
1560EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1561
1562/* ------------------------------------------------------------------------- */
1563
1564int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1565{
1566 int res;
1567
1568 mutex_lock(&core_lock);
1569 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1570 mutex_unlock(&core_lock);
1571
1572 return res;
1573}
1574EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1575
1576static int __process_new_driver(struct device *dev, void *data)
1577{
1578 if (dev->type != &i2c_adapter_type)
1579 return 0;
1580 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1581}
1582
1583/*
1584 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1585 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1586 */
1587
1588int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1589{
1590 int res;
1591
1592 /* Can't register until after driver model init */
1593 if (WARN_ON(!is_registered))
1594 return -EAGAIN;
1595
1596 /* add the driver to the list of i2c drivers in the driver core */
1597 driver->driver.owner = owner;
1598 driver->driver.bus = &i2c_bus_type;
1599 INIT_LIST_HEAD(&driver->clients);
1600
1601 /* When registration returns, the driver core
1602 * will have called probe() for all matching-but-unbound devices.
1603 */
1604 res = driver_register(&driver->driver);
1605 if (res)
1606 return res;
1607
1608 pr_debug("driver [%s] registered\n", driver->driver.name);
1609
1610 /* Walk the adapters that are already present */
1611 i2c_for_each_dev(driver, __process_new_driver);
1612
1613 return 0;
1614}
1615EXPORT_SYMBOL(i2c_register_driver);
1616
1617static int __process_removed_driver(struct device *dev, void *data)
1618{
1619 if (dev->type == &i2c_adapter_type)
1620 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1621 return 0;
1622}
1623
1624/**
1625 * i2c_del_driver - unregister I2C driver
1626 * @driver: the driver being unregistered
1627 * Context: can sleep
1628 */
1629void i2c_del_driver(struct i2c_driver *driver)
1630{
1631 i2c_for_each_dev(driver, __process_removed_driver);
1632
1633 driver_unregister(&driver->driver);
1634 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1635}
1636EXPORT_SYMBOL(i2c_del_driver);
1637
1638/* ------------------------------------------------------------------------- */
1639
1640/**
1641 * i2c_use_client - increments the reference count of the i2c client structure
1642 * @client: the client being referenced
1643 *
1644 * Each live reference to a client should be refcounted. The driver model does
1645 * that automatically as part of driver binding, so that most drivers don't
1646 * need to do this explicitly: they hold a reference until they're unbound
1647 * from the device.
1648 *
1649 * A pointer to the client with the incremented reference counter is returned.
1650 */
1651struct i2c_client *i2c_use_client(struct i2c_client *client)
1652{
1653 if (client && get_device(&client->dev))
1654 return client;
1655 return NULL;
1656}
1657EXPORT_SYMBOL(i2c_use_client);
1658
1659/**
1660 * i2c_release_client - release a use of the i2c client structure
1661 * @client: the client being no longer referenced
1662 *
1663 * Must be called when a user of a client is finished with it.
1664 */
1665void i2c_release_client(struct i2c_client *client)
1666{
1667 if (client)
1668 put_device(&client->dev);
1669}
1670EXPORT_SYMBOL(i2c_release_client);
1671
1672struct i2c_cmd_arg {
1673 unsigned cmd;
1674 void *arg;
1675};
1676
1677static int i2c_cmd(struct device *dev, void *_arg)
1678{
1679 struct i2c_client *client = i2c_verify_client(dev);
1680 struct i2c_cmd_arg *arg = _arg;
1681 struct i2c_driver *driver;
1682
1683 if (!client || !client->dev.driver)
1684 return 0;
1685
1686 driver = to_i2c_driver(client->dev.driver);
1687 if (driver->command)
1688 driver->command(client, arg->cmd, arg->arg);
1689 return 0;
1690}
1691
1692void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1693{
1694 struct i2c_cmd_arg cmd_arg;
1695
1696 cmd_arg.cmd = cmd;
1697 cmd_arg.arg = arg;
1698 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1699}
1700EXPORT_SYMBOL(i2c_clients_command);
1701
1702static int __init i2c_init(void)
1703{
1704 int retval;
1705
1706 retval = of_alias_get_highest_id("i2c");
1707
1708 down_write(&__i2c_board_lock);
1709 if (retval >= __i2c_first_dynamic_bus_num)
1710 __i2c_first_dynamic_bus_num = retval + 1;
1711 up_write(&__i2c_board_lock);
1712
1713 retval = bus_register(&i2c_bus_type);
1714 if (retval)
1715 return retval;
1716
1717 is_registered = true;
1718
1719#ifdef CONFIG_I2C_COMPAT
1720 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1721 if (!i2c_adapter_compat_class) {
1722 retval = -ENOMEM;
1723 goto bus_err;
1724 }
1725#endif
1726 retval = i2c_add_driver(&dummy_driver);
1727 if (retval)
1728 goto class_err;
1729
1730 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1731 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1732 if (IS_ENABLED(CONFIG_ACPI))
1733 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1734
1735 return 0;
1736
1737class_err:
1738#ifdef CONFIG_I2C_COMPAT
1739 class_compat_unregister(i2c_adapter_compat_class);
1740bus_err:
1741#endif
1742 is_registered = false;
1743 bus_unregister(&i2c_bus_type);
1744 return retval;
1745}
1746
1747static void __exit i2c_exit(void)
1748{
1749 if (IS_ENABLED(CONFIG_ACPI))
1750 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1751 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1752 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1753 i2c_del_driver(&dummy_driver);
1754#ifdef CONFIG_I2C_COMPAT
1755 class_compat_unregister(i2c_adapter_compat_class);
1756#endif
1757 bus_unregister(&i2c_bus_type);
1758 tracepoint_synchronize_unregister();
1759}
1760
1761/* We must initialize early, because some subsystems register i2c drivers
1762 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1763 */
1764postcore_initcall(i2c_init);
1765module_exit(i2c_exit);
1766
1767/* ----------------------------------------------------
1768 * the functional interface to the i2c busses.
1769 * ----------------------------------------------------
1770 */
1771
1772/* Check if val is exceeding the quirk IFF quirk is non 0 */
1773#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1774
1775static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1776{
1777 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1778 err_msg, msg->addr, msg->len,
1779 msg->flags & I2C_M_RD ? "read" : "write");
1780 return -EOPNOTSUPP;
1781}
1782
1783static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1784{
1785 const struct i2c_adapter_quirks *q = adap->quirks;
1786 int max_num = q->max_num_msgs, i;
1787 bool do_len_check = true;
1788
1789 if (q->flags & I2C_AQ_COMB) {
1790 max_num = 2;
1791
1792 /* special checks for combined messages */
1793 if (num == 2) {
1794 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1795 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1796
1797 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1798 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1799
1800 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1801 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1802
1803 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1804 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1805
1806 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1807 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1808
1809 do_len_check = false;
1810 }
1811 }
1812
1813 if (i2c_quirk_exceeded(num, max_num))
1814 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1815
1816 for (i = 0; i < num; i++) {
1817 u16 len = msgs[i].len;
1818
1819 if (msgs[i].flags & I2C_M_RD) {
1820 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1821 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1822 } else {
1823 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1824 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1825 }
1826 }
1827
1828 return 0;
1829}
1830
1831/**
1832 * __i2c_transfer - unlocked flavor of i2c_transfer
1833 * @adap: Handle to I2C bus
1834 * @msgs: One or more messages to execute before STOP is issued to
1835 * terminate the operation; each message begins with a START.
1836 * @num: Number of messages to be executed.
1837 *
1838 * Returns negative errno, else the number of messages executed.
1839 *
1840 * Adapter lock must be held when calling this function. No debug logging
1841 * takes place. adap->algo->master_xfer existence isn't checked.
1842 */
1843int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1844{
1845 unsigned long orig_jiffies;
1846 int ret, try;
1847
1848 if (WARN_ON(!msgs || num < 1))
1849 return -EINVAL;
1850
1851 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1852 return -EOPNOTSUPP;
1853
1854 /*
1855 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1856 * enabled. This is an efficient way of keeping the for-loop from
1857 * being executed when not needed.
1858 */
1859 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1860 int i;
1861 for (i = 0; i < num; i++)
1862 if (msgs[i].flags & I2C_M_RD)
1863 trace_i2c_read(adap, &msgs[i], i);
1864 else
1865 trace_i2c_write(adap, &msgs[i], i);
1866 }
1867
1868 /* Retry automatically on arbitration loss */
1869 orig_jiffies = jiffies;
1870 for (ret = 0, try = 0; try <= adap->retries; try++) {
1871 ret = adap->algo->master_xfer(adap, msgs, num);
1872 if (ret != -EAGAIN)
1873 break;
1874 if (time_after(jiffies, orig_jiffies + adap->timeout))
1875 break;
1876 }
1877
1878 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1879 int i;
1880 for (i = 0; i < ret; i++)
1881 if (msgs[i].flags & I2C_M_RD)
1882 trace_i2c_reply(adap, &msgs[i], i);
1883 trace_i2c_result(adap, num, ret);
1884 }
1885
1886 return ret;
1887}
1888EXPORT_SYMBOL(__i2c_transfer);
1889
1890/**
1891 * i2c_transfer - execute a single or combined I2C message
1892 * @adap: Handle to I2C bus
1893 * @msgs: One or more messages to execute before STOP is issued to
1894 * terminate the operation; each message begins with a START.
1895 * @num: Number of messages to be executed.
1896 *
1897 * Returns negative errno, else the number of messages executed.
1898 *
1899 * Note that there is no requirement that each message be sent to
1900 * the same slave address, although that is the most common model.
1901 */
1902int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1903{
1904 int ret;
1905
1906 /* REVISIT the fault reporting model here is weak:
1907 *
1908 * - When we get an error after receiving N bytes from a slave,
1909 * there is no way to report "N".
1910 *
1911 * - When we get a NAK after transmitting N bytes to a slave,
1912 * there is no way to report "N" ... or to let the master
1913 * continue executing the rest of this combined message, if
1914 * that's the appropriate response.
1915 *
1916 * - When for example "num" is two and we successfully complete
1917 * the first message but get an error part way through the
1918 * second, it's unclear whether that should be reported as
1919 * one (discarding status on the second message) or errno
1920 * (discarding status on the first one).
1921 */
1922
1923 if (adap->algo->master_xfer) {
1924#ifdef DEBUG
1925 for (ret = 0; ret < num; ret++) {
1926 dev_dbg(&adap->dev,
1927 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1928 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1929 msgs[ret].addr, msgs[ret].len,
1930 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1931 }
1932#endif
1933
1934 if (in_atomic() || irqs_disabled()) {
1935 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1936 if (!ret)
1937 /* I2C activity is ongoing. */
1938 return -EAGAIN;
1939 } else {
1940 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1941 }
1942
1943 ret = __i2c_transfer(adap, msgs, num);
1944 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1945
1946 return ret;
1947 } else {
1948 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1949 return -EOPNOTSUPP;
1950 }
1951}
1952EXPORT_SYMBOL(i2c_transfer);
1953
1954/**
1955 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1956 * to/from a buffer
1957 * @client: Handle to slave device
1958 * @buf: Where the data is stored
1959 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1960 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1961 *
1962 * Returns negative errno, or else the number of bytes transferred.
1963 */
1964int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1965 int count, u16 flags)
1966{
1967 int ret;
1968 struct i2c_msg msg = {
1969 .addr = client->addr,
1970 .flags = flags | (client->flags & I2C_M_TEN),
1971 .len = count,
1972 .buf = buf,
1973 };
1974
1975 ret = i2c_transfer(client->adapter, &msg, 1);
1976
1977 /*
1978 * If everything went ok (i.e. 1 msg transferred), return #bytes
1979 * transferred, else error code.
1980 */
1981 return (ret == 1) ? count : ret;
1982}
1983EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1984
1985/**
1986 * i2c_get_device_id - get manufacturer, part id and die revision of a device
1987 * @client: The device to query
1988 * @id: The queried information
1989 *
1990 * Returns negative errno on error, zero on success.
1991 */
1992int i2c_get_device_id(const struct i2c_client *client,
1993 struct i2c_device_identity *id)
1994{
1995 struct i2c_adapter *adap = client->adapter;
1996 union i2c_smbus_data raw_id;
1997 int ret;
1998
1999 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2000 return -EOPNOTSUPP;
2001
2002 raw_id.block[0] = 3;
2003 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2004 I2C_SMBUS_READ, client->addr << 1,
2005 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2006 if (ret)
2007 return ret;
2008
2009 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2010 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2011 id->die_revision = raw_id.block[3] & 0x7;
2012 return 0;
2013}
2014EXPORT_SYMBOL_GPL(i2c_get_device_id);
2015
2016/* ----------------------------------------------------
2017 * the i2c address scanning function
2018 * Will not work for 10-bit addresses!
2019 * ----------------------------------------------------
2020 */
2021
2022/*
2023 * Legacy default probe function, mostly relevant for SMBus. The default
2024 * probe method is a quick write, but it is known to corrupt the 24RF08
2025 * EEPROMs due to a state machine bug, and could also irreversibly
2026 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2027 * we use a short byte read instead. Also, some bus drivers don't implement
2028 * quick write, so we fallback to a byte read in that case too.
2029 * On x86, there is another special case for FSC hardware monitoring chips,
2030 * which want regular byte reads (address 0x73.) Fortunately, these are the
2031 * only known chips using this I2C address on PC hardware.
2032 * Returns 1 if probe succeeded, 0 if not.
2033 */
2034static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2035{
2036 int err;
2037 union i2c_smbus_data dummy;
2038
2039#ifdef CONFIG_X86
2040 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2041 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2042 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2043 I2C_SMBUS_BYTE_DATA, &dummy);
2044 else
2045#endif
2046 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2047 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2048 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2049 I2C_SMBUS_QUICK, NULL);
2050 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2051 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2052 I2C_SMBUS_BYTE, &dummy);
2053 else {
2054 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2055 addr);
2056 err = -EOPNOTSUPP;
2057 }
2058
2059 return err >= 0;
2060}
2061
2062static int i2c_detect_address(struct i2c_client *temp_client,
2063 struct i2c_driver *driver)
2064{
2065 struct i2c_board_info info;
2066 struct i2c_adapter *adapter = temp_client->adapter;
2067 int addr = temp_client->addr;
2068 int err;
2069
2070 /* Make sure the address is valid */
2071 err = i2c_check_7bit_addr_validity_strict(addr);
2072 if (err) {
2073 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2074 addr);
2075 return err;
2076 }
2077
2078 /* Skip if already in use (7 bit, no need to encode flags) */
2079 if (i2c_check_addr_busy(adapter, addr))
2080 return 0;
2081
2082 /* Make sure there is something at this address */
2083 if (!i2c_default_probe(adapter, addr))
2084 return 0;
2085
2086 /* Finally call the custom detection function */
2087 memset(&info, 0, sizeof(struct i2c_board_info));
2088 info.addr = addr;
2089 err = driver->detect(temp_client, &info);
2090 if (err) {
2091 /* -ENODEV is returned if the detection fails. We catch it
2092 here as this isn't an error. */
2093 return err == -ENODEV ? 0 : err;
2094 }
2095
2096 /* Consistency check */
2097 if (info.type[0] == '\0') {
2098 dev_err(&adapter->dev,
2099 "%s detection function provided no name for 0x%x\n",
2100 driver->driver.name, addr);
2101 } else {
2102 struct i2c_client *client;
2103
2104 /* Detection succeeded, instantiate the device */
2105 if (adapter->class & I2C_CLASS_DEPRECATED)
2106 dev_warn(&adapter->dev,
2107 "This adapter will soon drop class based instantiation of devices. "
2108 "Please make sure client 0x%02x gets instantiated by other means. "
2109 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2110 info.addr);
2111
2112 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2113 info.type, info.addr);
2114 client = i2c_new_device(adapter, &info);
2115 if (client)
2116 list_add_tail(&client->detected, &driver->clients);
2117 else
2118 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2119 info.type, info.addr);
2120 }
2121 return 0;
2122}
2123
2124static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2125{
2126 const unsigned short *address_list;
2127 struct i2c_client *temp_client;
2128 int i, err = 0;
2129 int adap_id = i2c_adapter_id(adapter);
2130
2131 address_list = driver->address_list;
2132 if (!driver->detect || !address_list)
2133 return 0;
2134
2135 /* Warn that the adapter lost class based instantiation */
2136 if (adapter->class == I2C_CLASS_DEPRECATED) {
2137 dev_dbg(&adapter->dev,
2138 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2139 "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2140 driver->driver.name);
2141 return 0;
2142 }
2143
2144 /* Stop here if the classes do not match */
2145 if (!(adapter->class & driver->class))
2146 return 0;
2147
2148 /* Set up a temporary client to help detect callback */
2149 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2150 if (!temp_client)
2151 return -ENOMEM;
2152 temp_client->adapter = adapter;
2153
2154 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2155 dev_dbg(&adapter->dev,
2156 "found normal entry for adapter %d, addr 0x%02x\n",
2157 adap_id, address_list[i]);
2158 temp_client->addr = address_list[i];
2159 err = i2c_detect_address(temp_client, driver);
2160 if (unlikely(err))
2161 break;
2162 }
2163
2164 kfree(temp_client);
2165 return err;
2166}
2167
2168int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2169{
2170 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2171 I2C_SMBUS_QUICK, NULL) >= 0;
2172}
2173EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2174
2175struct i2c_client *
2176i2c_new_probed_device(struct i2c_adapter *adap,
2177 struct i2c_board_info *info,
2178 unsigned short const *addr_list,
2179 int (*probe)(struct i2c_adapter *, unsigned short addr))
2180{
2181 int i;
2182
2183 if (!probe)
2184 probe = i2c_default_probe;
2185
2186 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2187 /* Check address validity */
2188 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2189 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2190 addr_list[i]);
2191 continue;
2192 }
2193
2194 /* Check address availability (7 bit, no need to encode flags) */
2195 if (i2c_check_addr_busy(adap, addr_list[i])) {
2196 dev_dbg(&adap->dev,
2197 "Address 0x%02x already in use, not probing\n",
2198 addr_list[i]);
2199 continue;
2200 }
2201
2202 /* Test address responsiveness */
2203 if (probe(adap, addr_list[i]))
2204 break;
2205 }
2206
2207 if (addr_list[i] == I2C_CLIENT_END) {
2208 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2209 return NULL;
2210 }
2211
2212 info->addr = addr_list[i];
2213 return i2c_new_device(adap, info);
2214}
2215EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2216
2217struct i2c_adapter *i2c_get_adapter(int nr)
2218{
2219 struct i2c_adapter *adapter;
2220
2221 mutex_lock(&core_lock);
2222 adapter = idr_find(&i2c_adapter_idr, nr);
2223 if (!adapter)
2224 goto exit;
2225
2226 if (try_module_get(adapter->owner))
2227 get_device(&adapter->dev);
2228 else
2229 adapter = NULL;
2230
2231 exit:
2232 mutex_unlock(&core_lock);
2233 return adapter;
2234}
2235EXPORT_SYMBOL(i2c_get_adapter);
2236
2237void i2c_put_adapter(struct i2c_adapter *adap)
2238{
2239 if (!adap)
2240 return;
2241
2242 put_device(&adap->dev);
2243 module_put(adap->owner);
2244}
2245EXPORT_SYMBOL(i2c_put_adapter);
2246
2247/**
2248 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2249 * @msg: the message to be checked
2250 * @threshold: the minimum number of bytes for which using DMA makes sense
2251 *
2252 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2253 * Or a valid pointer to be used with DMA. After use, release it by
2254 * calling i2c_release_dma_safe_msg_buf().
2255 *
2256 * This function must only be called from process context!
2257 */
2258u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2259{
2260 if (msg->len < threshold)
2261 return NULL;
2262
2263 if (msg->flags & I2C_M_DMA_SAFE)
2264 return msg->buf;
2265
2266 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2267 msg->addr, msg->len);
2268
2269 if (msg->flags & I2C_M_RD)
2270 return kzalloc(msg->len, GFP_KERNEL);
2271 else
2272 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2273}
2274EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2275
2276/**
2277 * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2278 * @msg: the message to be synced with
2279 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2280 */
2281void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2282{
2283 if (!buf || buf == msg->buf)
2284 return;
2285
2286 if (msg->flags & I2C_M_RD)
2287 memcpy(msg->buf, buf, msg->len);
2288
2289 kfree(buf);
2290}
2291EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2292
2293MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2294MODULE_DESCRIPTION("I2C-Bus main module");
2295MODULE_LICENSE("GPL");