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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Linux I2C core
4 *
5 * Copyright (C) 1995-99 Simon G. Vogl
6 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8 * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 *
10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
11 */
12
13#define pr_fmt(fmt) "i2c-core: " fmt
14
15#include <dt-bindings/i2c/i2c.h>
16#include <linux/acpi.h>
17#include <linux/clk/clk-conf.h>
18#include <linux/completion.h>
19#include <linux/delay.h>
20#include <linux/err.h>
21#include <linux/errno.h>
22#include <linux/gpio/consumer.h>
23#include <linux/i2c.h>
24#include <linux/i2c-smbus.h>
25#include <linux/idr.h>
26#include <linux/init.h>
27#include <linux/irqflags.h>
28#include <linux/jump_label.h>
29#include <linux/kernel.h>
30#include <linux/module.h>
31#include <linux/mutex.h>
32#include <linux/of_device.h>
33#include <linux/of.h>
34#include <linux/of_irq.h>
35#include <linux/pm_domain.h>
36#include <linux/pm_runtime.h>
37#include <linux/pm_wakeirq.h>
38#include <linux/property.h>
39#include <linux/rwsem.h>
40#include <linux/slab.h>
41
42#include "i2c-core.h"
43
44#define CREATE_TRACE_POINTS
45#include <trace/events/i2c.h>
46
47#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
48#define I2C_ADDR_OFFSET_SLAVE 0x1000
49
50#define I2C_ADDR_7BITS_MAX 0x77
51#define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
52
53#define I2C_ADDR_DEVICE_ID 0x7c
54
55/*
56 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
57 * deletion of detected devices are serialized
58 */
59static DEFINE_MUTEX(core_lock);
60static DEFINE_IDR(i2c_adapter_idr);
61
62static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
63
64static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
65static bool is_registered;
66
67int i2c_transfer_trace_reg(void)
68{
69 static_branch_inc(&i2c_trace_msg_key);
70 return 0;
71}
72
73void i2c_transfer_trace_unreg(void)
74{
75 static_branch_dec(&i2c_trace_msg_key);
76}
77
78const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
79 const struct i2c_client *client)
80{
81 if (!(id && client))
82 return NULL;
83
84 while (id->name[0]) {
85 if (strcmp(client->name, id->name) == 0)
86 return id;
87 id++;
88 }
89 return NULL;
90}
91EXPORT_SYMBOL_GPL(i2c_match_id);
92
93static int i2c_device_match(struct device *dev, struct device_driver *drv)
94{
95 struct i2c_client *client = i2c_verify_client(dev);
96 struct i2c_driver *driver;
97
98
99 /* Attempt an OF style match */
100 if (i2c_of_match_device(drv->of_match_table, client))
101 return 1;
102
103 /* Then ACPI style match */
104 if (acpi_driver_match_device(dev, drv))
105 return 1;
106
107 driver = to_i2c_driver(drv);
108
109 /* Finally an I2C match */
110 if (i2c_match_id(driver->id_table, client))
111 return 1;
112
113 return 0;
114}
115
116static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
117{
118 struct i2c_client *client = to_i2c_client(dev);
119 int rc;
120
121 rc = of_device_uevent_modalias(dev, env);
122 if (rc != -ENODEV)
123 return rc;
124
125 rc = acpi_device_uevent_modalias(dev, env);
126 if (rc != -ENODEV)
127 return rc;
128
129 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
130}
131
132/* i2c bus recovery routines */
133static int get_scl_gpio_value(struct i2c_adapter *adap)
134{
135 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
136}
137
138static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
139{
140 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
141}
142
143static int get_sda_gpio_value(struct i2c_adapter *adap)
144{
145 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
146}
147
148static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
149{
150 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
151}
152
153static int i2c_generic_bus_free(struct i2c_adapter *adap)
154{
155 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
156 int ret = -EOPNOTSUPP;
157
158 if (bri->get_bus_free)
159 ret = bri->get_bus_free(adap);
160 else if (bri->get_sda)
161 ret = bri->get_sda(adap);
162
163 if (ret < 0)
164 return ret;
165
166 return ret ? 0 : -EBUSY;
167}
168
169/*
170 * We are generating clock pulses. ndelay() determines durating of clk pulses.
171 * We will generate clock with rate 100 KHz and so duration of both clock levels
172 * is: delay in ns = (10^6 / 100) / 2
173 */
174#define RECOVERY_NDELAY 5000
175#define RECOVERY_CLK_CNT 9
176
177int i2c_generic_scl_recovery(struct i2c_adapter *adap)
178{
179 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
180 int i = 0, scl = 1, ret = 0;
181
182 if (bri->prepare_recovery)
183 bri->prepare_recovery(adap);
184
185 /*
186 * If we can set SDA, we will always create a STOP to ensure additional
187 * pulses will do no harm. This is achieved by letting SDA follow SCL
188 * half a cycle later. Check the 'incomplete_write_byte' fault injector
189 * for details.
190 */
191 bri->set_scl(adap, scl);
192 ndelay(RECOVERY_NDELAY / 2);
193 if (bri->set_sda)
194 bri->set_sda(adap, scl);
195 ndelay(RECOVERY_NDELAY / 2);
196
197 /*
198 * By this time SCL is high, as we need to give 9 falling-rising edges
199 */
200 while (i++ < RECOVERY_CLK_CNT * 2) {
201 if (scl) {
202 /* SCL shouldn't be low here */
203 if (!bri->get_scl(adap)) {
204 dev_err(&adap->dev,
205 "SCL is stuck low, exit recovery\n");
206 ret = -EBUSY;
207 break;
208 }
209 }
210
211 scl = !scl;
212 bri->set_scl(adap, scl);
213 /* Creating STOP again, see above */
214 ndelay(RECOVERY_NDELAY / 2);
215 if (bri->set_sda)
216 bri->set_sda(adap, scl);
217 ndelay(RECOVERY_NDELAY / 2);
218
219 if (scl) {
220 ret = i2c_generic_bus_free(adap);
221 if (ret == 0)
222 break;
223 }
224 }
225
226 /* If we can't check bus status, assume recovery worked */
227 if (ret == -EOPNOTSUPP)
228 ret = 0;
229
230 if (bri->unprepare_recovery)
231 bri->unprepare_recovery(adap);
232
233 return ret;
234}
235EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
236
237int i2c_recover_bus(struct i2c_adapter *adap)
238{
239 if (!adap->bus_recovery_info)
240 return -EOPNOTSUPP;
241
242 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
243 return adap->bus_recovery_info->recover_bus(adap);
244}
245EXPORT_SYMBOL_GPL(i2c_recover_bus);
246
247static void i2c_init_recovery(struct i2c_adapter *adap)
248{
249 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
250 char *err_str;
251
252 if (!bri)
253 return;
254
255 if (!bri->recover_bus) {
256 err_str = "no recover_bus() found";
257 goto err;
258 }
259
260 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
261 bri->get_scl = get_scl_gpio_value;
262 bri->set_scl = set_scl_gpio_value;
263 if (bri->sda_gpiod) {
264 bri->get_sda = get_sda_gpio_value;
265 /* FIXME: add proper flag instead of '0' once available */
266 if (gpiod_get_direction(bri->sda_gpiod) == 0)
267 bri->set_sda = set_sda_gpio_value;
268 }
269 return;
270 }
271
272 if (bri->recover_bus == i2c_generic_scl_recovery) {
273 /* Generic SCL recovery */
274 if (!bri->set_scl || !bri->get_scl) {
275 err_str = "no {get|set}_scl() found";
276 goto err;
277 }
278 if (!bri->set_sda && !bri->get_sda) {
279 err_str = "either get_sda() or set_sda() needed";
280 goto err;
281 }
282 }
283
284 return;
285 err:
286 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
287 adap->bus_recovery_info = NULL;
288}
289
290static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
291{
292 struct i2c_adapter *adap = client->adapter;
293 unsigned int irq;
294
295 if (!adap->host_notify_domain)
296 return -ENXIO;
297
298 if (client->flags & I2C_CLIENT_TEN)
299 return -EINVAL;
300
301 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
302
303 return irq > 0 ? irq : -ENXIO;
304}
305
306static int i2c_device_probe(struct device *dev)
307{
308 struct i2c_client *client = i2c_verify_client(dev);
309 struct i2c_driver *driver;
310 int status;
311
312 if (!client)
313 return 0;
314
315 driver = to_i2c_driver(dev->driver);
316
317 client->irq = client->init_irq;
318
319 if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
320 int irq = -ENOENT;
321
322 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
323 dev_dbg(dev, "Using Host Notify IRQ\n");
324 /* Keep adapter active when Host Notify is required */
325 pm_runtime_get_sync(&client->adapter->dev);
326 irq = i2c_smbus_host_notify_to_irq(client);
327 } else if (dev->of_node) {
328 irq = of_irq_get_byname(dev->of_node, "irq");
329 if (irq == -EINVAL || irq == -ENODATA)
330 irq = of_irq_get(dev->of_node, 0);
331 } else if (ACPI_COMPANION(dev)) {
332 irq = i2c_acpi_get_irq(client);
333 }
334 if (irq == -EPROBE_DEFER)
335 return irq;
336
337 if (irq < 0)
338 irq = 0;
339
340 client->irq = irq;
341 }
342
343 /*
344 * An I2C ID table is not mandatory, if and only if, a suitable OF
345 * or ACPI ID table is supplied for the probing device.
346 */
347 if (!driver->id_table &&
348 !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
349 !i2c_of_match_device(dev->driver->of_match_table, client))
350 return -ENODEV;
351
352 if (client->flags & I2C_CLIENT_WAKE) {
353 int wakeirq;
354
355 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
356 if (wakeirq == -EPROBE_DEFER)
357 return wakeirq;
358
359 device_init_wakeup(&client->dev, true);
360
361 if (wakeirq > 0 && wakeirq != client->irq)
362 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
363 else if (client->irq > 0)
364 status = dev_pm_set_wake_irq(dev, client->irq);
365 else
366 status = 0;
367
368 if (status)
369 dev_warn(&client->dev, "failed to set up wakeup irq\n");
370 }
371
372 dev_dbg(dev, "probe\n");
373
374 status = of_clk_set_defaults(dev->of_node, false);
375 if (status < 0)
376 goto err_clear_wakeup_irq;
377
378 status = dev_pm_domain_attach(&client->dev, true);
379 if (status)
380 goto err_clear_wakeup_irq;
381
382 /*
383 * When there are no more users of probe(),
384 * rename probe_new to probe.
385 */
386 if (driver->probe_new)
387 status = driver->probe_new(client);
388 else if (driver->probe)
389 status = driver->probe(client,
390 i2c_match_id(driver->id_table, client));
391 else
392 status = -EINVAL;
393
394 if (status)
395 goto err_detach_pm_domain;
396
397 return 0;
398
399err_detach_pm_domain:
400 dev_pm_domain_detach(&client->dev, true);
401err_clear_wakeup_irq:
402 dev_pm_clear_wake_irq(&client->dev);
403 device_init_wakeup(&client->dev, false);
404 return status;
405}
406
407static int i2c_device_remove(struct device *dev)
408{
409 struct i2c_client *client = i2c_verify_client(dev);
410 struct i2c_driver *driver;
411 int status = 0;
412
413 if (!client || !dev->driver)
414 return 0;
415
416 driver = to_i2c_driver(dev->driver);
417 if (driver->remove) {
418 dev_dbg(dev, "remove\n");
419 status = driver->remove(client);
420 }
421
422 dev_pm_domain_detach(&client->dev, true);
423
424 dev_pm_clear_wake_irq(&client->dev);
425 device_init_wakeup(&client->dev, false);
426
427 client->irq = 0;
428 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
429 pm_runtime_put(&client->adapter->dev);
430
431 return status;
432}
433
434static void i2c_device_shutdown(struct device *dev)
435{
436 struct i2c_client *client = i2c_verify_client(dev);
437 struct i2c_driver *driver;
438
439 if (!client || !dev->driver)
440 return;
441 driver = to_i2c_driver(dev->driver);
442 if (driver->shutdown)
443 driver->shutdown(client);
444}
445
446static void i2c_client_dev_release(struct device *dev)
447{
448 kfree(to_i2c_client(dev));
449}
450
451static ssize_t
452show_name(struct device *dev, struct device_attribute *attr, char *buf)
453{
454 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
455 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
456}
457static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
458
459static ssize_t
460show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
461{
462 struct i2c_client *client = to_i2c_client(dev);
463 int len;
464
465 len = of_device_modalias(dev, buf, PAGE_SIZE);
466 if (len != -ENODEV)
467 return len;
468
469 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
470 if (len != -ENODEV)
471 return len;
472
473 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
474}
475static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
476
477static struct attribute *i2c_dev_attrs[] = {
478 &dev_attr_name.attr,
479 /* modalias helps coldplug: modprobe $(cat .../modalias) */
480 &dev_attr_modalias.attr,
481 NULL
482};
483ATTRIBUTE_GROUPS(i2c_dev);
484
485struct bus_type i2c_bus_type = {
486 .name = "i2c",
487 .match = i2c_device_match,
488 .probe = i2c_device_probe,
489 .remove = i2c_device_remove,
490 .shutdown = i2c_device_shutdown,
491};
492EXPORT_SYMBOL_GPL(i2c_bus_type);
493
494struct device_type i2c_client_type = {
495 .groups = i2c_dev_groups,
496 .uevent = i2c_device_uevent,
497 .release = i2c_client_dev_release,
498};
499EXPORT_SYMBOL_GPL(i2c_client_type);
500
501
502/**
503 * i2c_verify_client - return parameter as i2c_client, or NULL
504 * @dev: device, probably from some driver model iterator
505 *
506 * When traversing the driver model tree, perhaps using driver model
507 * iterators like @device_for_each_child(), you can't assume very much
508 * about the nodes you find. Use this function to avoid oopses caused
509 * by wrongly treating some non-I2C device as an i2c_client.
510 */
511struct i2c_client *i2c_verify_client(struct device *dev)
512{
513 return (dev->type == &i2c_client_type)
514 ? to_i2c_client(dev)
515 : NULL;
516}
517EXPORT_SYMBOL(i2c_verify_client);
518
519
520/* Return a unique address which takes the flags of the client into account */
521static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
522{
523 unsigned short addr = client->addr;
524
525 /* For some client flags, add an arbitrary offset to avoid collisions */
526 if (client->flags & I2C_CLIENT_TEN)
527 addr |= I2C_ADDR_OFFSET_TEN_BIT;
528
529 if (client->flags & I2C_CLIENT_SLAVE)
530 addr |= I2C_ADDR_OFFSET_SLAVE;
531
532 return addr;
533}
534
535/* This is a permissive address validity check, I2C address map constraints
536 * are purposely not enforced, except for the general call address. */
537static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
538{
539 if (flags & I2C_CLIENT_TEN) {
540 /* 10-bit address, all values are valid */
541 if (addr > 0x3ff)
542 return -EINVAL;
543 } else {
544 /* 7-bit address, reject the general call address */
545 if (addr == 0x00 || addr > 0x7f)
546 return -EINVAL;
547 }
548 return 0;
549}
550
551/* And this is a strict address validity check, used when probing. If a
552 * device uses a reserved address, then it shouldn't be probed. 7-bit
553 * addressing is assumed, 10-bit address devices are rare and should be
554 * explicitly enumerated. */
555int i2c_check_7bit_addr_validity_strict(unsigned short addr)
556{
557 /*
558 * Reserved addresses per I2C specification:
559 * 0x00 General call address / START byte
560 * 0x01 CBUS address
561 * 0x02 Reserved for different bus format
562 * 0x03 Reserved for future purposes
563 * 0x04-0x07 Hs-mode master code
564 * 0x78-0x7b 10-bit slave addressing
565 * 0x7c-0x7f Reserved for future purposes
566 */
567 if (addr < 0x08 || addr > 0x77)
568 return -EINVAL;
569 return 0;
570}
571
572static int __i2c_check_addr_busy(struct device *dev, void *addrp)
573{
574 struct i2c_client *client = i2c_verify_client(dev);
575 int addr = *(int *)addrp;
576
577 if (client && i2c_encode_flags_to_addr(client) == addr)
578 return -EBUSY;
579 return 0;
580}
581
582/* walk up mux tree */
583static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
584{
585 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
586 int result;
587
588 result = device_for_each_child(&adapter->dev, &addr,
589 __i2c_check_addr_busy);
590
591 if (!result && parent)
592 result = i2c_check_mux_parents(parent, addr);
593
594 return result;
595}
596
597/* recurse down mux tree */
598static int i2c_check_mux_children(struct device *dev, void *addrp)
599{
600 int result;
601
602 if (dev->type == &i2c_adapter_type)
603 result = device_for_each_child(dev, addrp,
604 i2c_check_mux_children);
605 else
606 result = __i2c_check_addr_busy(dev, addrp);
607
608 return result;
609}
610
611static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
612{
613 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
614 int result = 0;
615
616 if (parent)
617 result = i2c_check_mux_parents(parent, addr);
618
619 if (!result)
620 result = device_for_each_child(&adapter->dev, &addr,
621 i2c_check_mux_children);
622
623 return result;
624}
625
626/**
627 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
628 * @adapter: Target I2C bus segment
629 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
630 * locks only this branch in the adapter tree
631 */
632static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
633 unsigned int flags)
634{
635 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
636}
637
638/**
639 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
640 * @adapter: Target I2C bus segment
641 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
642 * trylocks only this branch in the adapter tree
643 */
644static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
645 unsigned int flags)
646{
647 return rt_mutex_trylock(&adapter->bus_lock);
648}
649
650/**
651 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
652 * @adapter: Target I2C bus segment
653 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
654 * unlocks only this branch in the adapter tree
655 */
656static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
657 unsigned int flags)
658{
659 rt_mutex_unlock(&adapter->bus_lock);
660}
661
662static void i2c_dev_set_name(struct i2c_adapter *adap,
663 struct i2c_client *client,
664 struct i2c_board_info const *info)
665{
666 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
667
668 if (info && info->dev_name) {
669 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
670 return;
671 }
672
673 if (adev) {
674 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
675 return;
676 }
677
678 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
679 i2c_encode_flags_to_addr(client));
680}
681
682int i2c_dev_irq_from_resources(const struct resource *resources,
683 unsigned int num_resources)
684{
685 struct irq_data *irqd;
686 int i;
687
688 for (i = 0; i < num_resources; i++) {
689 const struct resource *r = &resources[i];
690
691 if (resource_type(r) != IORESOURCE_IRQ)
692 continue;
693
694 if (r->flags & IORESOURCE_BITS) {
695 irqd = irq_get_irq_data(r->start);
696 if (!irqd)
697 break;
698
699 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
700 }
701
702 return r->start;
703 }
704
705 return 0;
706}
707
708/**
709 * i2c_new_client_device - instantiate an i2c device
710 * @adap: the adapter managing the device
711 * @info: describes one I2C device; bus_num is ignored
712 * Context: can sleep
713 *
714 * Create an i2c device. Binding is handled through driver model
715 * probe()/remove() methods. A driver may be bound to this device when we
716 * return from this function, or any later moment (e.g. maybe hotplugging will
717 * load the driver module). This call is not appropriate for use by mainboard
718 * initialization logic, which usually runs during an arch_initcall() long
719 * before any i2c_adapter could exist.
720 *
721 * This returns the new i2c client, which may be saved for later use with
722 * i2c_unregister_device(); or an ERR_PTR to describe the error.
723 */
724struct i2c_client *
725i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
726{
727 struct i2c_client *client;
728 int status;
729
730 client = kzalloc(sizeof *client, GFP_KERNEL);
731 if (!client)
732 return ERR_PTR(-ENOMEM);
733
734 client->adapter = adap;
735
736 client->dev.platform_data = info->platform_data;
737 client->flags = info->flags;
738 client->addr = info->addr;
739
740 client->init_irq = info->irq;
741 if (!client->init_irq)
742 client->init_irq = i2c_dev_irq_from_resources(info->resources,
743 info->num_resources);
744
745 strlcpy(client->name, info->type, sizeof(client->name));
746
747 status = i2c_check_addr_validity(client->addr, client->flags);
748 if (status) {
749 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
750 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
751 goto out_err_silent;
752 }
753
754 /* Check for address business */
755 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
756 if (status)
757 goto out_err;
758
759 client->dev.parent = &client->adapter->dev;
760 client->dev.bus = &i2c_bus_type;
761 client->dev.type = &i2c_client_type;
762 client->dev.of_node = of_node_get(info->of_node);
763 client->dev.fwnode = info->fwnode;
764
765 i2c_dev_set_name(adap, client, info);
766
767 if (info->properties) {
768 status = device_add_properties(&client->dev, info->properties);
769 if (status) {
770 dev_err(&adap->dev,
771 "Failed to add properties to client %s: %d\n",
772 client->name, status);
773 goto out_err_put_of_node;
774 }
775 }
776
777 status = device_register(&client->dev);
778 if (status)
779 goto out_free_props;
780
781 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
782 client->name, dev_name(&client->dev));
783
784 return client;
785
786out_free_props:
787 if (info->properties)
788 device_remove_properties(&client->dev);
789out_err_put_of_node:
790 of_node_put(info->of_node);
791out_err:
792 dev_err(&adap->dev,
793 "Failed to register i2c client %s at 0x%02x (%d)\n",
794 client->name, client->addr, status);
795out_err_silent:
796 kfree(client);
797 return ERR_PTR(status);
798}
799EXPORT_SYMBOL_GPL(i2c_new_client_device);
800
801/**
802 * i2c_new_device - instantiate an i2c device
803 * @adap: the adapter managing the device
804 * @info: describes one I2C device; bus_num is ignored
805 * Context: can sleep
806 *
807 * This deprecated function has the same functionality as
808 * @i2c_new_client_device, it just returns NULL instead of an ERR_PTR in case of
809 * an error for compatibility with current I2C API. It will be removed once all
810 * users are converted.
811 *
812 * This returns the new i2c client, which may be saved for later use with
813 * i2c_unregister_device(); or NULL to indicate an error.
814 */
815struct i2c_client *
816i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
817{
818 struct i2c_client *ret;
819
820 ret = i2c_new_client_device(adap, info);
821 return IS_ERR(ret) ? NULL : ret;
822}
823EXPORT_SYMBOL_GPL(i2c_new_device);
824
825
826/**
827 * i2c_unregister_device - reverse effect of i2c_new_device()
828 * @client: value returned from i2c_new_device()
829 * Context: can sleep
830 */
831void i2c_unregister_device(struct i2c_client *client)
832{
833 if (IS_ERR_OR_NULL(client))
834 return;
835
836 if (client->dev.of_node) {
837 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
838 of_node_put(client->dev.of_node);
839 }
840
841 if (ACPI_COMPANION(&client->dev))
842 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
843 device_unregister(&client->dev);
844}
845EXPORT_SYMBOL_GPL(i2c_unregister_device);
846
847
848static const struct i2c_device_id dummy_id[] = {
849 { "dummy", 0 },
850 { },
851};
852
853static int dummy_probe(struct i2c_client *client,
854 const struct i2c_device_id *id)
855{
856 return 0;
857}
858
859static int dummy_remove(struct i2c_client *client)
860{
861 return 0;
862}
863
864static struct i2c_driver dummy_driver = {
865 .driver.name = "dummy",
866 .probe = dummy_probe,
867 .remove = dummy_remove,
868 .id_table = dummy_id,
869};
870
871/**
872 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
873 * @adapter: the adapter managing the device
874 * @address: seven bit address to be used
875 * Context: can sleep
876 *
877 * This returns an I2C client bound to the "dummy" driver, intended for use
878 * with devices that consume multiple addresses. Examples of such chips
879 * include various EEPROMS (like 24c04 and 24c08 models).
880 *
881 * These dummy devices have two main uses. First, most I2C and SMBus calls
882 * except i2c_transfer() need a client handle; the dummy will be that handle.
883 * And second, this prevents the specified address from being bound to a
884 * different driver.
885 *
886 * This returns the new i2c client, which should be saved for later use with
887 * i2c_unregister_device(); or an ERR_PTR to describe the error.
888 */
889struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
890{
891 struct i2c_board_info info = {
892 I2C_BOARD_INFO("dummy", address),
893 };
894
895 return i2c_new_client_device(adapter, &info);
896}
897EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
898
899/**
900 * i2c_new_dummy - return a new i2c device bound to a dummy driver
901 * @adapter: the adapter managing the device
902 * @address: seven bit address to be used
903 * Context: can sleep
904 *
905 * This deprecated function has the same functionality as @i2c_new_dummy_device,
906 * it just returns NULL instead of an ERR_PTR in case of an error for
907 * compatibility with current I2C API. It will be removed once all users are
908 * converted.
909 *
910 * This returns the new i2c client, which should be saved for later use with
911 * i2c_unregister_device(); or NULL to indicate an error.
912 */
913struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
914{
915 struct i2c_client *ret;
916
917 ret = i2c_new_dummy_device(adapter, address);
918 return IS_ERR(ret) ? NULL : ret;
919}
920EXPORT_SYMBOL_GPL(i2c_new_dummy);
921
922struct i2c_dummy_devres {
923 struct i2c_client *client;
924};
925
926static void devm_i2c_release_dummy(struct device *dev, void *res)
927{
928 struct i2c_dummy_devres *this = res;
929
930 i2c_unregister_device(this->client);
931}
932
933/**
934 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
935 * @dev: device the managed resource is bound to
936 * @adapter: the adapter managing the device
937 * @address: seven bit address to be used
938 * Context: can sleep
939 *
940 * This is the device-managed version of @i2c_new_dummy_device. It returns the
941 * new i2c client or an ERR_PTR in case of an error.
942 */
943struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
944 struct i2c_adapter *adapter,
945 u16 address)
946{
947 struct i2c_dummy_devres *dr;
948 struct i2c_client *client;
949
950 dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
951 if (!dr)
952 return ERR_PTR(-ENOMEM);
953
954 client = i2c_new_dummy_device(adapter, address);
955 if (IS_ERR(client)) {
956 devres_free(dr);
957 } else {
958 dr->client = client;
959 devres_add(dev, dr);
960 }
961
962 return client;
963}
964EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
965
966/**
967 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
968 * and create the associated device
969 * @client: Handle to the primary client
970 * @name: Handle to specify which secondary address to get
971 * @default_addr: Used as a fallback if no secondary address was specified
972 * Context: can sleep
973 *
974 * I2C clients can be composed of multiple I2C slaves bound together in a single
975 * component. The I2C client driver then binds to the master I2C slave and needs
976 * to create I2C dummy clients to communicate with all the other slaves.
977 *
978 * This function creates and returns an I2C dummy client whose I2C address is
979 * retrieved from the platform firmware based on the given slave name. If no
980 * address is specified by the firmware default_addr is used.
981 *
982 * On DT-based platforms the address is retrieved from the "reg" property entry
983 * cell whose "reg-names" value matches the slave name.
984 *
985 * This returns the new i2c client, which should be saved for later use with
986 * i2c_unregister_device(); or an ERR_PTR to describe the error.
987 */
988struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
989 const char *name,
990 u16 default_addr)
991{
992 struct device_node *np = client->dev.of_node;
993 u32 addr = default_addr;
994 int i;
995
996 if (np) {
997 i = of_property_match_string(np, "reg-names", name);
998 if (i >= 0)
999 of_property_read_u32_index(np, "reg", i, &addr);
1000 }
1001
1002 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1003 return i2c_new_dummy_device(client->adapter, addr);
1004}
1005EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1006
1007/* ------------------------------------------------------------------------- */
1008
1009/* I2C bus adapters -- one roots each I2C or SMBUS segment */
1010
1011static void i2c_adapter_dev_release(struct device *dev)
1012{
1013 struct i2c_adapter *adap = to_i2c_adapter(dev);
1014 complete(&adap->dev_released);
1015}
1016
1017unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1018{
1019 unsigned int depth = 0;
1020
1021 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1022 depth++;
1023
1024 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1025 "adapter depth exceeds lockdep subclass limit\n");
1026
1027 return depth;
1028}
1029EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1030
1031/*
1032 * Let users instantiate I2C devices through sysfs. This can be used when
1033 * platform initialization code doesn't contain the proper data for
1034 * whatever reason. Also useful for drivers that do device detection and
1035 * detection fails, either because the device uses an unexpected address,
1036 * or this is a compatible device with different ID register values.
1037 *
1038 * Parameter checking may look overzealous, but we really don't want
1039 * the user to provide incorrect parameters.
1040 */
1041static ssize_t
1042i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1043 const char *buf, size_t count)
1044{
1045 struct i2c_adapter *adap = to_i2c_adapter(dev);
1046 struct i2c_board_info info;
1047 struct i2c_client *client;
1048 char *blank, end;
1049 int res;
1050
1051 memset(&info, 0, sizeof(struct i2c_board_info));
1052
1053 blank = strchr(buf, ' ');
1054 if (!blank) {
1055 dev_err(dev, "%s: Missing parameters\n", "new_device");
1056 return -EINVAL;
1057 }
1058 if (blank - buf > I2C_NAME_SIZE - 1) {
1059 dev_err(dev, "%s: Invalid device name\n", "new_device");
1060 return -EINVAL;
1061 }
1062 memcpy(info.type, buf, blank - buf);
1063
1064 /* Parse remaining parameters, reject extra parameters */
1065 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1066 if (res < 1) {
1067 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1068 return -EINVAL;
1069 }
1070 if (res > 1 && end != '\n') {
1071 dev_err(dev, "%s: Extra parameters\n", "new_device");
1072 return -EINVAL;
1073 }
1074
1075 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1076 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1077 info.flags |= I2C_CLIENT_TEN;
1078 }
1079
1080 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1081 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1082 info.flags |= I2C_CLIENT_SLAVE;
1083 }
1084
1085 client = i2c_new_client_device(adap, &info);
1086 if (IS_ERR(client))
1087 return PTR_ERR(client);
1088
1089 /* Keep track of the added device */
1090 mutex_lock(&adap->userspace_clients_lock);
1091 list_add_tail(&client->detected, &adap->userspace_clients);
1092 mutex_unlock(&adap->userspace_clients_lock);
1093 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1094 info.type, info.addr);
1095
1096 return count;
1097}
1098static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1099
1100/*
1101 * And of course let the users delete the devices they instantiated, if
1102 * they got it wrong. This interface can only be used to delete devices
1103 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1104 * don't delete devices to which some kernel code still has references.
1105 *
1106 * Parameter checking may look overzealous, but we really don't want
1107 * the user to delete the wrong device.
1108 */
1109static ssize_t
1110i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1111 const char *buf, size_t count)
1112{
1113 struct i2c_adapter *adap = to_i2c_adapter(dev);
1114 struct i2c_client *client, *next;
1115 unsigned short addr;
1116 char end;
1117 int res;
1118
1119 /* Parse parameters, reject extra parameters */
1120 res = sscanf(buf, "%hi%c", &addr, &end);
1121 if (res < 1) {
1122 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1123 return -EINVAL;
1124 }
1125 if (res > 1 && end != '\n') {
1126 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1127 return -EINVAL;
1128 }
1129
1130 /* Make sure the device was added through sysfs */
1131 res = -ENOENT;
1132 mutex_lock_nested(&adap->userspace_clients_lock,
1133 i2c_adapter_depth(adap));
1134 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1135 detected) {
1136 if (i2c_encode_flags_to_addr(client) == addr) {
1137 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1138 "delete_device", client->name, client->addr);
1139
1140 list_del(&client->detected);
1141 i2c_unregister_device(client);
1142 res = count;
1143 break;
1144 }
1145 }
1146 mutex_unlock(&adap->userspace_clients_lock);
1147
1148 if (res < 0)
1149 dev_err(dev, "%s: Can't find device in list\n",
1150 "delete_device");
1151 return res;
1152}
1153static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1154 i2c_sysfs_delete_device);
1155
1156static struct attribute *i2c_adapter_attrs[] = {
1157 &dev_attr_name.attr,
1158 &dev_attr_new_device.attr,
1159 &dev_attr_delete_device.attr,
1160 NULL
1161};
1162ATTRIBUTE_GROUPS(i2c_adapter);
1163
1164struct device_type i2c_adapter_type = {
1165 .groups = i2c_adapter_groups,
1166 .release = i2c_adapter_dev_release,
1167};
1168EXPORT_SYMBOL_GPL(i2c_adapter_type);
1169
1170/**
1171 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1172 * @dev: device, probably from some driver model iterator
1173 *
1174 * When traversing the driver model tree, perhaps using driver model
1175 * iterators like @device_for_each_child(), you can't assume very much
1176 * about the nodes you find. Use this function to avoid oopses caused
1177 * by wrongly treating some non-I2C device as an i2c_adapter.
1178 */
1179struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1180{
1181 return (dev->type == &i2c_adapter_type)
1182 ? to_i2c_adapter(dev)
1183 : NULL;
1184}
1185EXPORT_SYMBOL(i2c_verify_adapter);
1186
1187#ifdef CONFIG_I2C_COMPAT
1188static struct class_compat *i2c_adapter_compat_class;
1189#endif
1190
1191static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1192{
1193 struct i2c_devinfo *devinfo;
1194
1195 down_read(&__i2c_board_lock);
1196 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1197 if (devinfo->busnum == adapter->nr
1198 && !i2c_new_device(adapter,
1199 &devinfo->board_info))
1200 dev_err(&adapter->dev,
1201 "Can't create device at 0x%02x\n",
1202 devinfo->board_info.addr);
1203 }
1204 up_read(&__i2c_board_lock);
1205}
1206
1207static int i2c_do_add_adapter(struct i2c_driver *driver,
1208 struct i2c_adapter *adap)
1209{
1210 /* Detect supported devices on that bus, and instantiate them */
1211 i2c_detect(adap, driver);
1212
1213 return 0;
1214}
1215
1216static int __process_new_adapter(struct device_driver *d, void *data)
1217{
1218 return i2c_do_add_adapter(to_i2c_driver(d), data);
1219}
1220
1221static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1222 .lock_bus = i2c_adapter_lock_bus,
1223 .trylock_bus = i2c_adapter_trylock_bus,
1224 .unlock_bus = i2c_adapter_unlock_bus,
1225};
1226
1227static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1228{
1229 struct irq_domain *domain = adap->host_notify_domain;
1230 irq_hw_number_t hwirq;
1231
1232 if (!domain)
1233 return;
1234
1235 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1236 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1237
1238 irq_domain_remove(domain);
1239 adap->host_notify_domain = NULL;
1240}
1241
1242static int i2c_host_notify_irq_map(struct irq_domain *h,
1243 unsigned int virq,
1244 irq_hw_number_t hw_irq_num)
1245{
1246 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1247
1248 return 0;
1249}
1250
1251static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1252 .map = i2c_host_notify_irq_map,
1253};
1254
1255static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1256{
1257 struct irq_domain *domain;
1258
1259 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1260 return 0;
1261
1262 domain = irq_domain_create_linear(adap->dev.fwnode,
1263 I2C_ADDR_7BITS_COUNT,
1264 &i2c_host_notify_irq_ops, adap);
1265 if (!domain)
1266 return -ENOMEM;
1267
1268 adap->host_notify_domain = domain;
1269
1270 return 0;
1271}
1272
1273/**
1274 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1275 * I2C client.
1276 * @adap: the adapter
1277 * @addr: the I2C address of the notifying device
1278 * Context: can't sleep
1279 *
1280 * Helper function to be called from an I2C bus driver's interrupt
1281 * handler. It will schedule the Host Notify IRQ.
1282 */
1283int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1284{
1285 int irq;
1286
1287 if (!adap)
1288 return -EINVAL;
1289
1290 irq = irq_find_mapping(adap->host_notify_domain, addr);
1291 if (irq <= 0)
1292 return -ENXIO;
1293
1294 generic_handle_irq(irq);
1295
1296 return 0;
1297}
1298EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1299
1300static int i2c_register_adapter(struct i2c_adapter *adap)
1301{
1302 int res = -EINVAL;
1303
1304 /* Can't register until after driver model init */
1305 if (WARN_ON(!is_registered)) {
1306 res = -EAGAIN;
1307 goto out_list;
1308 }
1309
1310 /* Sanity checks */
1311 if (WARN(!adap->name[0], "i2c adapter has no name"))
1312 goto out_list;
1313
1314 if (!adap->algo) {
1315 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1316 goto out_list;
1317 }
1318
1319 if (!adap->lock_ops)
1320 adap->lock_ops = &i2c_adapter_lock_ops;
1321
1322 adap->locked_flags = 0;
1323 rt_mutex_init(&adap->bus_lock);
1324 rt_mutex_init(&adap->mux_lock);
1325 mutex_init(&adap->userspace_clients_lock);
1326 INIT_LIST_HEAD(&adap->userspace_clients);
1327
1328 /* Set default timeout to 1 second if not already set */
1329 if (adap->timeout == 0)
1330 adap->timeout = HZ;
1331
1332 /* register soft irqs for Host Notify */
1333 res = i2c_setup_host_notify_irq_domain(adap);
1334 if (res) {
1335 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1336 adap->name, res);
1337 goto out_list;
1338 }
1339
1340 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1341 adap->dev.bus = &i2c_bus_type;
1342 adap->dev.type = &i2c_adapter_type;
1343 res = device_register(&adap->dev);
1344 if (res) {
1345 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1346 goto out_list;
1347 }
1348
1349 res = of_i2c_setup_smbus_alert(adap);
1350 if (res)
1351 goto out_reg;
1352
1353 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1354
1355 pm_runtime_no_callbacks(&adap->dev);
1356 pm_suspend_ignore_children(&adap->dev, true);
1357 pm_runtime_enable(&adap->dev);
1358
1359#ifdef CONFIG_I2C_COMPAT
1360 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1361 adap->dev.parent);
1362 if (res)
1363 dev_warn(&adap->dev,
1364 "Failed to create compatibility class link\n");
1365#endif
1366
1367 i2c_init_recovery(adap);
1368
1369 /* create pre-declared device nodes */
1370 of_i2c_register_devices(adap);
1371 i2c_acpi_register_devices(adap);
1372 i2c_acpi_install_space_handler(adap);
1373
1374 if (adap->nr < __i2c_first_dynamic_bus_num)
1375 i2c_scan_static_board_info(adap);
1376
1377 /* Notify drivers */
1378 mutex_lock(&core_lock);
1379 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1380 mutex_unlock(&core_lock);
1381
1382 return 0;
1383
1384out_reg:
1385 init_completion(&adap->dev_released);
1386 device_unregister(&adap->dev);
1387 wait_for_completion(&adap->dev_released);
1388out_list:
1389 mutex_lock(&core_lock);
1390 idr_remove(&i2c_adapter_idr, adap->nr);
1391 mutex_unlock(&core_lock);
1392 return res;
1393}
1394
1395/**
1396 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1397 * @adap: the adapter to register (with adap->nr initialized)
1398 * Context: can sleep
1399 *
1400 * See i2c_add_numbered_adapter() for details.
1401 */
1402static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1403{
1404 int id;
1405
1406 mutex_lock(&core_lock);
1407 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1408 mutex_unlock(&core_lock);
1409 if (WARN(id < 0, "couldn't get idr"))
1410 return id == -ENOSPC ? -EBUSY : id;
1411
1412 return i2c_register_adapter(adap);
1413}
1414
1415/**
1416 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1417 * @adapter: the adapter to add
1418 * Context: can sleep
1419 *
1420 * This routine is used to declare an I2C adapter when its bus number
1421 * doesn't matter or when its bus number is specified by an dt alias.
1422 * Examples of bases when the bus number doesn't matter: I2C adapters
1423 * dynamically added by USB links or PCI plugin cards.
1424 *
1425 * When this returns zero, a new bus number was allocated and stored
1426 * in adap->nr, and the specified adapter became available for clients.
1427 * Otherwise, a negative errno value is returned.
1428 */
1429int i2c_add_adapter(struct i2c_adapter *adapter)
1430{
1431 struct device *dev = &adapter->dev;
1432 int id;
1433
1434 if (dev->of_node) {
1435 id = of_alias_get_id(dev->of_node, "i2c");
1436 if (id >= 0) {
1437 adapter->nr = id;
1438 return __i2c_add_numbered_adapter(adapter);
1439 }
1440 }
1441
1442 mutex_lock(&core_lock);
1443 id = idr_alloc(&i2c_adapter_idr, adapter,
1444 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1445 mutex_unlock(&core_lock);
1446 if (WARN(id < 0, "couldn't get idr"))
1447 return id;
1448
1449 adapter->nr = id;
1450
1451 return i2c_register_adapter(adapter);
1452}
1453EXPORT_SYMBOL(i2c_add_adapter);
1454
1455/**
1456 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1457 * @adap: the adapter to register (with adap->nr initialized)
1458 * Context: can sleep
1459 *
1460 * This routine is used to declare an I2C adapter when its bus number
1461 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1462 * or otherwise built in to the system's mainboard, and where i2c_board_info
1463 * is used to properly configure I2C devices.
1464 *
1465 * If the requested bus number is set to -1, then this function will behave
1466 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1467 *
1468 * If no devices have pre-been declared for this bus, then be sure to
1469 * register the adapter before any dynamically allocated ones. Otherwise
1470 * the required bus ID may not be available.
1471 *
1472 * When this returns zero, the specified adapter became available for
1473 * clients using the bus number provided in adap->nr. Also, the table
1474 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1475 * and the appropriate driver model device nodes are created. Otherwise, a
1476 * negative errno value is returned.
1477 */
1478int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1479{
1480 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1481 return i2c_add_adapter(adap);
1482
1483 return __i2c_add_numbered_adapter(adap);
1484}
1485EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1486
1487static void i2c_do_del_adapter(struct i2c_driver *driver,
1488 struct i2c_adapter *adapter)
1489{
1490 struct i2c_client *client, *_n;
1491
1492 /* Remove the devices we created ourselves as the result of hardware
1493 * probing (using a driver's detect method) */
1494 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1495 if (client->adapter == adapter) {
1496 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1497 client->name, client->addr);
1498 list_del(&client->detected);
1499 i2c_unregister_device(client);
1500 }
1501 }
1502}
1503
1504static int __unregister_client(struct device *dev, void *dummy)
1505{
1506 struct i2c_client *client = i2c_verify_client(dev);
1507 if (client && strcmp(client->name, "dummy"))
1508 i2c_unregister_device(client);
1509 return 0;
1510}
1511
1512static int __unregister_dummy(struct device *dev, void *dummy)
1513{
1514 struct i2c_client *client = i2c_verify_client(dev);
1515 i2c_unregister_device(client);
1516 return 0;
1517}
1518
1519static int __process_removed_adapter(struct device_driver *d, void *data)
1520{
1521 i2c_do_del_adapter(to_i2c_driver(d), data);
1522 return 0;
1523}
1524
1525/**
1526 * i2c_del_adapter - unregister I2C adapter
1527 * @adap: the adapter being unregistered
1528 * Context: can sleep
1529 *
1530 * This unregisters an I2C adapter which was previously registered
1531 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1532 */
1533void i2c_del_adapter(struct i2c_adapter *adap)
1534{
1535 struct i2c_adapter *found;
1536 struct i2c_client *client, *next;
1537
1538 /* First make sure that this adapter was ever added */
1539 mutex_lock(&core_lock);
1540 found = idr_find(&i2c_adapter_idr, adap->nr);
1541 mutex_unlock(&core_lock);
1542 if (found != adap) {
1543 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1544 return;
1545 }
1546
1547 i2c_acpi_remove_space_handler(adap);
1548 /* Tell drivers about this removal */
1549 mutex_lock(&core_lock);
1550 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1551 __process_removed_adapter);
1552 mutex_unlock(&core_lock);
1553
1554 /* Remove devices instantiated from sysfs */
1555 mutex_lock_nested(&adap->userspace_clients_lock,
1556 i2c_adapter_depth(adap));
1557 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1558 detected) {
1559 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1560 client->addr);
1561 list_del(&client->detected);
1562 i2c_unregister_device(client);
1563 }
1564 mutex_unlock(&adap->userspace_clients_lock);
1565
1566 /* Detach any active clients. This can't fail, thus we do not
1567 * check the returned value. This is a two-pass process, because
1568 * we can't remove the dummy devices during the first pass: they
1569 * could have been instantiated by real devices wishing to clean
1570 * them up properly, so we give them a chance to do that first. */
1571 device_for_each_child(&adap->dev, NULL, __unregister_client);
1572 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1573
1574#ifdef CONFIG_I2C_COMPAT
1575 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1576 adap->dev.parent);
1577#endif
1578
1579 /* device name is gone after device_unregister */
1580 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1581
1582 pm_runtime_disable(&adap->dev);
1583
1584 i2c_host_notify_irq_teardown(adap);
1585
1586 /* wait until all references to the device are gone
1587 *
1588 * FIXME: This is old code and should ideally be replaced by an
1589 * alternative which results in decoupling the lifetime of the struct
1590 * device from the i2c_adapter, like spi or netdev do. Any solution
1591 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1592 */
1593 init_completion(&adap->dev_released);
1594 device_unregister(&adap->dev);
1595 wait_for_completion(&adap->dev_released);
1596
1597 /* free bus id */
1598 mutex_lock(&core_lock);
1599 idr_remove(&i2c_adapter_idr, adap->nr);
1600 mutex_unlock(&core_lock);
1601
1602 /* Clear the device structure in case this adapter is ever going to be
1603 added again */
1604 memset(&adap->dev, 0, sizeof(adap->dev));
1605}
1606EXPORT_SYMBOL(i2c_del_adapter);
1607
1608/**
1609 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1610 * @dev: The device to scan for I2C timing properties
1611 * @t: the i2c_timings struct to be filled with values
1612 * @use_defaults: bool to use sane defaults derived from the I2C specification
1613 * when properties are not found, otherwise use 0
1614 *
1615 * Scan the device for the generic I2C properties describing timing parameters
1616 * for the signal and fill the given struct with the results. If a property was
1617 * not found and use_defaults was true, then maximum timings are assumed which
1618 * are derived from the I2C specification. If use_defaults is not used, the
1619 * results will be 0, so drivers can apply their own defaults later. The latter
1620 * is mainly intended for avoiding regressions of existing drivers which want
1621 * to switch to this function. New drivers almost always should use the defaults.
1622 */
1623
1624void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1625{
1626 int ret;
1627
1628 memset(t, 0, sizeof(*t));
1629
1630 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1631 if (ret && use_defaults)
1632 t->bus_freq_hz = 100000;
1633
1634 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1635 if (ret && use_defaults) {
1636 if (t->bus_freq_hz <= 100000)
1637 t->scl_rise_ns = 1000;
1638 else if (t->bus_freq_hz <= 400000)
1639 t->scl_rise_ns = 300;
1640 else
1641 t->scl_rise_ns = 120;
1642 }
1643
1644 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1645 if (ret && use_defaults) {
1646 if (t->bus_freq_hz <= 400000)
1647 t->scl_fall_ns = 300;
1648 else
1649 t->scl_fall_ns = 120;
1650 }
1651
1652 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1653
1654 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1655 if (ret && use_defaults)
1656 t->sda_fall_ns = t->scl_fall_ns;
1657
1658 device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1659}
1660EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1661
1662/* ------------------------------------------------------------------------- */
1663
1664int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1665{
1666 int res;
1667
1668 mutex_lock(&core_lock);
1669 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1670 mutex_unlock(&core_lock);
1671
1672 return res;
1673}
1674EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1675
1676static int __process_new_driver(struct device *dev, void *data)
1677{
1678 if (dev->type != &i2c_adapter_type)
1679 return 0;
1680 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1681}
1682
1683/*
1684 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1685 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1686 */
1687
1688int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1689{
1690 int res;
1691
1692 /* Can't register until after driver model init */
1693 if (WARN_ON(!is_registered))
1694 return -EAGAIN;
1695
1696 /* add the driver to the list of i2c drivers in the driver core */
1697 driver->driver.owner = owner;
1698 driver->driver.bus = &i2c_bus_type;
1699 INIT_LIST_HEAD(&driver->clients);
1700
1701 /* When registration returns, the driver core
1702 * will have called probe() for all matching-but-unbound devices.
1703 */
1704 res = driver_register(&driver->driver);
1705 if (res)
1706 return res;
1707
1708 pr_debug("driver [%s] registered\n", driver->driver.name);
1709
1710 /* Walk the adapters that are already present */
1711 i2c_for_each_dev(driver, __process_new_driver);
1712
1713 return 0;
1714}
1715EXPORT_SYMBOL(i2c_register_driver);
1716
1717static int __process_removed_driver(struct device *dev, void *data)
1718{
1719 if (dev->type == &i2c_adapter_type)
1720 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1721 return 0;
1722}
1723
1724/**
1725 * i2c_del_driver - unregister I2C driver
1726 * @driver: the driver being unregistered
1727 * Context: can sleep
1728 */
1729void i2c_del_driver(struct i2c_driver *driver)
1730{
1731 i2c_for_each_dev(driver, __process_removed_driver);
1732
1733 driver_unregister(&driver->driver);
1734 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1735}
1736EXPORT_SYMBOL(i2c_del_driver);
1737
1738/* ------------------------------------------------------------------------- */
1739
1740/**
1741 * i2c_use_client - increments the reference count of the i2c client structure
1742 * @client: the client being referenced
1743 *
1744 * Each live reference to a client should be refcounted. The driver model does
1745 * that automatically as part of driver binding, so that most drivers don't
1746 * need to do this explicitly: they hold a reference until they're unbound
1747 * from the device.
1748 *
1749 * A pointer to the client with the incremented reference counter is returned.
1750 */
1751struct i2c_client *i2c_use_client(struct i2c_client *client)
1752{
1753 if (client && get_device(&client->dev))
1754 return client;
1755 return NULL;
1756}
1757EXPORT_SYMBOL(i2c_use_client);
1758
1759/**
1760 * i2c_release_client - release a use of the i2c client structure
1761 * @client: the client being no longer referenced
1762 *
1763 * Must be called when a user of a client is finished with it.
1764 */
1765void i2c_release_client(struct i2c_client *client)
1766{
1767 if (client)
1768 put_device(&client->dev);
1769}
1770EXPORT_SYMBOL(i2c_release_client);
1771
1772struct i2c_cmd_arg {
1773 unsigned cmd;
1774 void *arg;
1775};
1776
1777static int i2c_cmd(struct device *dev, void *_arg)
1778{
1779 struct i2c_client *client = i2c_verify_client(dev);
1780 struct i2c_cmd_arg *arg = _arg;
1781 struct i2c_driver *driver;
1782
1783 if (!client || !client->dev.driver)
1784 return 0;
1785
1786 driver = to_i2c_driver(client->dev.driver);
1787 if (driver->command)
1788 driver->command(client, arg->cmd, arg->arg);
1789 return 0;
1790}
1791
1792void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1793{
1794 struct i2c_cmd_arg cmd_arg;
1795
1796 cmd_arg.cmd = cmd;
1797 cmd_arg.arg = arg;
1798 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1799}
1800EXPORT_SYMBOL(i2c_clients_command);
1801
1802static int __init i2c_init(void)
1803{
1804 int retval;
1805
1806 retval = of_alias_get_highest_id("i2c");
1807
1808 down_write(&__i2c_board_lock);
1809 if (retval >= __i2c_first_dynamic_bus_num)
1810 __i2c_first_dynamic_bus_num = retval + 1;
1811 up_write(&__i2c_board_lock);
1812
1813 retval = bus_register(&i2c_bus_type);
1814 if (retval)
1815 return retval;
1816
1817 is_registered = true;
1818
1819#ifdef CONFIG_I2C_COMPAT
1820 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1821 if (!i2c_adapter_compat_class) {
1822 retval = -ENOMEM;
1823 goto bus_err;
1824 }
1825#endif
1826 retval = i2c_add_driver(&dummy_driver);
1827 if (retval)
1828 goto class_err;
1829
1830 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1831 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1832 if (IS_ENABLED(CONFIG_ACPI))
1833 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1834
1835 return 0;
1836
1837class_err:
1838#ifdef CONFIG_I2C_COMPAT
1839 class_compat_unregister(i2c_adapter_compat_class);
1840bus_err:
1841#endif
1842 is_registered = false;
1843 bus_unregister(&i2c_bus_type);
1844 return retval;
1845}
1846
1847static void __exit i2c_exit(void)
1848{
1849 if (IS_ENABLED(CONFIG_ACPI))
1850 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1851 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1852 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1853 i2c_del_driver(&dummy_driver);
1854#ifdef CONFIG_I2C_COMPAT
1855 class_compat_unregister(i2c_adapter_compat_class);
1856#endif
1857 bus_unregister(&i2c_bus_type);
1858 tracepoint_synchronize_unregister();
1859}
1860
1861/* We must initialize early, because some subsystems register i2c drivers
1862 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1863 */
1864postcore_initcall(i2c_init);
1865module_exit(i2c_exit);
1866
1867/* ----------------------------------------------------
1868 * the functional interface to the i2c busses.
1869 * ----------------------------------------------------
1870 */
1871
1872/* Check if val is exceeding the quirk IFF quirk is non 0 */
1873#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1874
1875static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1876{
1877 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1878 err_msg, msg->addr, msg->len,
1879 msg->flags & I2C_M_RD ? "read" : "write");
1880 return -EOPNOTSUPP;
1881}
1882
1883static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1884{
1885 const struct i2c_adapter_quirks *q = adap->quirks;
1886 int max_num = q->max_num_msgs, i;
1887 bool do_len_check = true;
1888
1889 if (q->flags & I2C_AQ_COMB) {
1890 max_num = 2;
1891
1892 /* special checks for combined messages */
1893 if (num == 2) {
1894 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1895 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1896
1897 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1898 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1899
1900 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1901 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1902
1903 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1904 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1905
1906 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1907 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1908
1909 do_len_check = false;
1910 }
1911 }
1912
1913 if (i2c_quirk_exceeded(num, max_num))
1914 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1915
1916 for (i = 0; i < num; i++) {
1917 u16 len = msgs[i].len;
1918
1919 if (msgs[i].flags & I2C_M_RD) {
1920 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1921 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1922
1923 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1924 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1925 } else {
1926 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1927 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1928
1929 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1930 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1931 }
1932 }
1933
1934 return 0;
1935}
1936
1937/**
1938 * __i2c_transfer - unlocked flavor of i2c_transfer
1939 * @adap: Handle to I2C bus
1940 * @msgs: One or more messages to execute before STOP is issued to
1941 * terminate the operation; each message begins with a START.
1942 * @num: Number of messages to be executed.
1943 *
1944 * Returns negative errno, else the number of messages executed.
1945 *
1946 * Adapter lock must be held when calling this function. No debug logging
1947 * takes place. adap->algo->master_xfer existence isn't checked.
1948 */
1949int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1950{
1951 unsigned long orig_jiffies;
1952 int ret, try;
1953
1954 if (WARN_ON(!msgs || num < 1))
1955 return -EINVAL;
1956
1957 ret = __i2c_check_suspended(adap);
1958 if (ret)
1959 return ret;
1960
1961 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1962 return -EOPNOTSUPP;
1963
1964 /*
1965 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1966 * enabled. This is an efficient way of keeping the for-loop from
1967 * being executed when not needed.
1968 */
1969 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1970 int i;
1971 for (i = 0; i < num; i++)
1972 if (msgs[i].flags & I2C_M_RD)
1973 trace_i2c_read(adap, &msgs[i], i);
1974 else
1975 trace_i2c_write(adap, &msgs[i], i);
1976 }
1977
1978 /* Retry automatically on arbitration loss */
1979 orig_jiffies = jiffies;
1980 for (ret = 0, try = 0; try <= adap->retries; try++) {
1981 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
1982 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
1983 else
1984 ret = adap->algo->master_xfer(adap, msgs, num);
1985
1986 if (ret != -EAGAIN)
1987 break;
1988 if (time_after(jiffies, orig_jiffies + adap->timeout))
1989 break;
1990 }
1991
1992 if (static_branch_unlikely(&i2c_trace_msg_key)) {
1993 int i;
1994 for (i = 0; i < ret; i++)
1995 if (msgs[i].flags & I2C_M_RD)
1996 trace_i2c_reply(adap, &msgs[i], i);
1997 trace_i2c_result(adap, num, ret);
1998 }
1999
2000 return ret;
2001}
2002EXPORT_SYMBOL(__i2c_transfer);
2003
2004/**
2005 * i2c_transfer - execute a single or combined I2C message
2006 * @adap: Handle to I2C bus
2007 * @msgs: One or more messages to execute before STOP is issued to
2008 * terminate the operation; each message begins with a START.
2009 * @num: Number of messages to be executed.
2010 *
2011 * Returns negative errno, else the number of messages executed.
2012 *
2013 * Note that there is no requirement that each message be sent to
2014 * the same slave address, although that is the most common model.
2015 */
2016int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2017{
2018 int ret;
2019
2020 if (!adap->algo->master_xfer) {
2021 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2022 return -EOPNOTSUPP;
2023 }
2024
2025 /* REVISIT the fault reporting model here is weak:
2026 *
2027 * - When we get an error after receiving N bytes from a slave,
2028 * there is no way to report "N".
2029 *
2030 * - When we get a NAK after transmitting N bytes to a slave,
2031 * there is no way to report "N" ... or to let the master
2032 * continue executing the rest of this combined message, if
2033 * that's the appropriate response.
2034 *
2035 * - When for example "num" is two and we successfully complete
2036 * the first message but get an error part way through the
2037 * second, it's unclear whether that should be reported as
2038 * one (discarding status on the second message) or errno
2039 * (discarding status on the first one).
2040 */
2041 ret = __i2c_lock_bus_helper(adap);
2042 if (ret)
2043 return ret;
2044
2045 ret = __i2c_transfer(adap, msgs, num);
2046 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2047
2048 return ret;
2049}
2050EXPORT_SYMBOL(i2c_transfer);
2051
2052/**
2053 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2054 * to/from a buffer
2055 * @client: Handle to slave device
2056 * @buf: Where the data is stored
2057 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2058 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2059 *
2060 * Returns negative errno, or else the number of bytes transferred.
2061 */
2062int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2063 int count, u16 flags)
2064{
2065 int ret;
2066 struct i2c_msg msg = {
2067 .addr = client->addr,
2068 .flags = flags | (client->flags & I2C_M_TEN),
2069 .len = count,
2070 .buf = buf,
2071 };
2072
2073 ret = i2c_transfer(client->adapter, &msg, 1);
2074
2075 /*
2076 * If everything went ok (i.e. 1 msg transferred), return #bytes
2077 * transferred, else error code.
2078 */
2079 return (ret == 1) ? count : ret;
2080}
2081EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2082
2083/**
2084 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2085 * @client: The device to query
2086 * @id: The queried information
2087 *
2088 * Returns negative errno on error, zero on success.
2089 */
2090int i2c_get_device_id(const struct i2c_client *client,
2091 struct i2c_device_identity *id)
2092{
2093 struct i2c_adapter *adap = client->adapter;
2094 union i2c_smbus_data raw_id;
2095 int ret;
2096
2097 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2098 return -EOPNOTSUPP;
2099
2100 raw_id.block[0] = 3;
2101 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2102 I2C_SMBUS_READ, client->addr << 1,
2103 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2104 if (ret)
2105 return ret;
2106
2107 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2108 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2109 id->die_revision = raw_id.block[3] & 0x7;
2110 return 0;
2111}
2112EXPORT_SYMBOL_GPL(i2c_get_device_id);
2113
2114/* ----------------------------------------------------
2115 * the i2c address scanning function
2116 * Will not work for 10-bit addresses!
2117 * ----------------------------------------------------
2118 */
2119
2120/*
2121 * Legacy default probe function, mostly relevant for SMBus. The default
2122 * probe method is a quick write, but it is known to corrupt the 24RF08
2123 * EEPROMs due to a state machine bug, and could also irreversibly
2124 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2125 * we use a short byte read instead. Also, some bus drivers don't implement
2126 * quick write, so we fallback to a byte read in that case too.
2127 * On x86, there is another special case for FSC hardware monitoring chips,
2128 * which want regular byte reads (address 0x73.) Fortunately, these are the
2129 * only known chips using this I2C address on PC hardware.
2130 * Returns 1 if probe succeeded, 0 if not.
2131 */
2132static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2133{
2134 int err;
2135 union i2c_smbus_data dummy;
2136
2137#ifdef CONFIG_X86
2138 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2139 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2140 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2141 I2C_SMBUS_BYTE_DATA, &dummy);
2142 else
2143#endif
2144 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2145 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2146 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2147 I2C_SMBUS_QUICK, NULL);
2148 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2149 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2150 I2C_SMBUS_BYTE, &dummy);
2151 else {
2152 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2153 addr);
2154 err = -EOPNOTSUPP;
2155 }
2156
2157 return err >= 0;
2158}
2159
2160static int i2c_detect_address(struct i2c_client *temp_client,
2161 struct i2c_driver *driver)
2162{
2163 struct i2c_board_info info;
2164 struct i2c_adapter *adapter = temp_client->adapter;
2165 int addr = temp_client->addr;
2166 int err;
2167
2168 /* Make sure the address is valid */
2169 err = i2c_check_7bit_addr_validity_strict(addr);
2170 if (err) {
2171 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2172 addr);
2173 return err;
2174 }
2175
2176 /* Skip if already in use (7 bit, no need to encode flags) */
2177 if (i2c_check_addr_busy(adapter, addr))
2178 return 0;
2179
2180 /* Make sure there is something at this address */
2181 if (!i2c_default_probe(adapter, addr))
2182 return 0;
2183
2184 /* Finally call the custom detection function */
2185 memset(&info, 0, sizeof(struct i2c_board_info));
2186 info.addr = addr;
2187 err = driver->detect(temp_client, &info);
2188 if (err) {
2189 /* -ENODEV is returned if the detection fails. We catch it
2190 here as this isn't an error. */
2191 return err == -ENODEV ? 0 : err;
2192 }
2193
2194 /* Consistency check */
2195 if (info.type[0] == '\0') {
2196 dev_err(&adapter->dev,
2197 "%s detection function provided no name for 0x%x\n",
2198 driver->driver.name, addr);
2199 } else {
2200 struct i2c_client *client;
2201
2202 /* Detection succeeded, instantiate the device */
2203 if (adapter->class & I2C_CLASS_DEPRECATED)
2204 dev_warn(&adapter->dev,
2205 "This adapter will soon drop class based instantiation of devices. "
2206 "Please make sure client 0x%02x gets instantiated by other means. "
2207 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2208 info.addr);
2209
2210 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2211 info.type, info.addr);
2212 client = i2c_new_device(adapter, &info);
2213 if (client)
2214 list_add_tail(&client->detected, &driver->clients);
2215 else
2216 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2217 info.type, info.addr);
2218 }
2219 return 0;
2220}
2221
2222static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2223{
2224 const unsigned short *address_list;
2225 struct i2c_client *temp_client;
2226 int i, err = 0;
2227 int adap_id = i2c_adapter_id(adapter);
2228
2229 address_list = driver->address_list;
2230 if (!driver->detect || !address_list)
2231 return 0;
2232
2233 /* Warn that the adapter lost class based instantiation */
2234 if (adapter->class == I2C_CLASS_DEPRECATED) {
2235 dev_dbg(&adapter->dev,
2236 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2237 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2238 driver->driver.name);
2239 return 0;
2240 }
2241
2242 /* Stop here if the classes do not match */
2243 if (!(adapter->class & driver->class))
2244 return 0;
2245
2246 /* Set up a temporary client to help detect callback */
2247 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2248 if (!temp_client)
2249 return -ENOMEM;
2250 temp_client->adapter = adapter;
2251
2252 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2253 dev_dbg(&adapter->dev,
2254 "found normal entry for adapter %d, addr 0x%02x\n",
2255 adap_id, address_list[i]);
2256 temp_client->addr = address_list[i];
2257 err = i2c_detect_address(temp_client, driver);
2258 if (unlikely(err))
2259 break;
2260 }
2261
2262 kfree(temp_client);
2263 return err;
2264}
2265
2266int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2267{
2268 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2269 I2C_SMBUS_QUICK, NULL) >= 0;
2270}
2271EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2272
2273struct i2c_client *
2274i2c_new_probed_device(struct i2c_adapter *adap,
2275 struct i2c_board_info *info,
2276 unsigned short const *addr_list,
2277 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2278{
2279 int i;
2280
2281 if (!probe)
2282 probe = i2c_default_probe;
2283
2284 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2285 /* Check address validity */
2286 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2287 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2288 addr_list[i]);
2289 continue;
2290 }
2291
2292 /* Check address availability (7 bit, no need to encode flags) */
2293 if (i2c_check_addr_busy(adap, addr_list[i])) {
2294 dev_dbg(&adap->dev,
2295 "Address 0x%02x already in use, not probing\n",
2296 addr_list[i]);
2297 continue;
2298 }
2299
2300 /* Test address responsiveness */
2301 if (probe(adap, addr_list[i]))
2302 break;
2303 }
2304
2305 if (addr_list[i] == I2C_CLIENT_END) {
2306 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2307 return NULL;
2308 }
2309
2310 info->addr = addr_list[i];
2311 return i2c_new_device(adap, info);
2312}
2313EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2314
2315struct i2c_adapter *i2c_get_adapter(int nr)
2316{
2317 struct i2c_adapter *adapter;
2318
2319 mutex_lock(&core_lock);
2320 adapter = idr_find(&i2c_adapter_idr, nr);
2321 if (!adapter)
2322 goto exit;
2323
2324 if (try_module_get(adapter->owner))
2325 get_device(&adapter->dev);
2326 else
2327 adapter = NULL;
2328
2329 exit:
2330 mutex_unlock(&core_lock);
2331 return adapter;
2332}
2333EXPORT_SYMBOL(i2c_get_adapter);
2334
2335void i2c_put_adapter(struct i2c_adapter *adap)
2336{
2337 if (!adap)
2338 return;
2339
2340 put_device(&adap->dev);
2341 module_put(adap->owner);
2342}
2343EXPORT_SYMBOL(i2c_put_adapter);
2344
2345/**
2346 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2347 * @msg: the message to be checked
2348 * @threshold: the minimum number of bytes for which using DMA makes sense.
2349 * Should at least be 1.
2350 *
2351 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2352 * Or a valid pointer to be used with DMA. After use, release it by
2353 * calling i2c_put_dma_safe_msg_buf().
2354 *
2355 * This function must only be called from process context!
2356 */
2357u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2358{
2359 /* also skip 0-length msgs for bogus thresholds of 0 */
2360 if (!threshold)
2361 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2362 msg->addr);
2363 if (msg->len < threshold || msg->len == 0)
2364 return NULL;
2365
2366 if (msg->flags & I2C_M_DMA_SAFE)
2367 return msg->buf;
2368
2369 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2370 msg->addr, msg->len);
2371
2372 if (msg->flags & I2C_M_RD)
2373 return kzalloc(msg->len, GFP_KERNEL);
2374 else
2375 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2376}
2377EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2378
2379/**
2380 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2381 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2382 * @msg: the message which the buffer corresponds to
2383 * @xferred: bool saying if the message was transferred
2384 */
2385void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2386{
2387 if (!buf || buf == msg->buf)
2388 return;
2389
2390 if (xferred && msg->flags & I2C_M_RD)
2391 memcpy(msg->buf, buf, msg->len);
2392
2393 kfree(buf);
2394}
2395EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2396
2397MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2398MODULE_DESCRIPTION("I2C-Bus main module");
2399MODULE_LICENSE("GPL");