1 // SPDX-License-Identifier: GPL-2.0-or-later
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>
10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
13 #define pr_fmt(fmt) "i2c-core: " fmt
15 #include <dt-bindings/i2c/i2c.h>
16 #include <linux/acpi.h>
17 #include <linux/clk/clk-conf.h>
18 #include <linux/completion.h>
19 #include <linux/delay.h>
20 #include <linux/err.h>
21 #include <linux/errno.h>
22 #include <linux/gpio/consumer.h>
23 #include <linux/i2c.h>
24 #include <linux/i2c-smbus.h>
25 #include <linux/idr.h>
26 #include <linux/init.h>
27 #include <linux/interrupt.h>
28 #include <linux/irqflags.h>
29 #include <linux/jump_label.h>
30 #include <linux/kernel.h>
31 #include <linux/module.h>
32 #include <linux/mutex.h>
33 #include <linux/of_device.h>
35 #include <linux/of_irq.h>
36 #include <linux/pinctrl/consumer.h>
37 #include <linux/pinctrl/devinfo.h>
38 #include <linux/pm_domain.h>
39 #include <linux/pm_runtime.h>
40 #include <linux/pm_wakeirq.h>
41 #include <linux/property.h>
42 #include <linux/rwsem.h>
43 #include <linux/slab.h>
47 #define CREATE_TRACE_POINTS
48 #include <trace/events/i2c.h>
50 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
51 #define I2C_ADDR_OFFSET_SLAVE 0x1000
53 #define I2C_ADDR_7BITS_MAX 0x77
54 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
56 #define I2C_ADDR_DEVICE_ID 0x7c
59 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
60 * deletion of detected devices are serialized
62 static DEFINE_MUTEX(core_lock);
63 static DEFINE_IDR(i2c_adapter_idr);
65 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
67 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
68 static bool is_registered;
70 int i2c_transfer_trace_reg(void)
72 static_branch_inc(&i2c_trace_msg_key);
76 void i2c_transfer_trace_unreg(void)
78 static_branch_dec(&i2c_trace_msg_key);
81 const char *i2c_freq_mode_string(u32 bus_freq_hz)
83 switch (bus_freq_hz) {
84 case I2C_MAX_STANDARD_MODE_FREQ:
85 return "Standard Mode (100 kHz)";
86 case I2C_MAX_FAST_MODE_FREQ:
87 return "Fast Mode (400 kHz)";
88 case I2C_MAX_FAST_MODE_PLUS_FREQ:
89 return "Fast Mode Plus (1.0 MHz)";
90 case I2C_MAX_TURBO_MODE_FREQ:
91 return "Turbo Mode (1.4 MHz)";
92 case I2C_MAX_HIGH_SPEED_MODE_FREQ:
93 return "High Speed Mode (3.4 MHz)";
94 case I2C_MAX_ULTRA_FAST_MODE_FREQ:
95 return "Ultra Fast Mode (5.0 MHz)";
97 return "Unknown Mode";
100 EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
102 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
103 const struct i2c_client *client)
108 while (id->name[0]) {
109 if (strcmp(client->name, id->name) == 0)
115 EXPORT_SYMBOL_GPL(i2c_match_id);
117 const void *i2c_get_match_data(const struct i2c_client *client)
119 struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
120 const struct i2c_device_id *match;
123 data = device_get_match_data(&client->dev);
125 match = i2c_match_id(driver->id_table, client);
129 data = (const void *)match->driver_data;
134 EXPORT_SYMBOL(i2c_get_match_data);
136 static int i2c_device_match(struct device *dev, struct device_driver *drv)
138 struct i2c_client *client = i2c_verify_client(dev);
139 struct i2c_driver *driver;
142 /* Attempt an OF style match */
143 if (i2c_of_match_device(drv->of_match_table, client))
146 /* Then ACPI style match */
147 if (acpi_driver_match_device(dev, drv))
150 driver = to_i2c_driver(drv);
152 /* Finally an I2C match */
153 if (i2c_match_id(driver->id_table, client))
159 static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
161 const struct i2c_client *client = to_i2c_client(dev);
164 rc = of_device_uevent_modalias(dev, env);
168 rc = acpi_device_uevent_modalias(dev, env);
172 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
175 /* i2c bus recovery routines */
176 static int get_scl_gpio_value(struct i2c_adapter *adap)
178 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
181 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
183 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
186 static int get_sda_gpio_value(struct i2c_adapter *adap)
188 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
191 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
193 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
196 static int i2c_generic_bus_free(struct i2c_adapter *adap)
198 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
199 int ret = -EOPNOTSUPP;
201 if (bri->get_bus_free)
202 ret = bri->get_bus_free(adap);
203 else if (bri->get_sda)
204 ret = bri->get_sda(adap);
209 return ret ? 0 : -EBUSY;
213 * We are generating clock pulses. ndelay() determines durating of clk pulses.
214 * We will generate clock with rate 100 KHz and so duration of both clock levels
215 * is: delay in ns = (10^6 / 100) / 2
217 #define RECOVERY_NDELAY 5000
218 #define RECOVERY_CLK_CNT 9
220 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
222 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
223 int i = 0, scl = 1, ret = 0;
225 if (bri->prepare_recovery)
226 bri->prepare_recovery(adap);
228 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
231 * If we can set SDA, we will always create a STOP to ensure additional
232 * pulses will do no harm. This is achieved by letting SDA follow SCL
233 * half a cycle later. Check the 'incomplete_write_byte' fault injector
234 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
235 * here for simplicity.
237 bri->set_scl(adap, scl);
238 ndelay(RECOVERY_NDELAY);
240 bri->set_sda(adap, scl);
241 ndelay(RECOVERY_NDELAY / 2);
244 * By this time SCL is high, as we need to give 9 falling-rising edges
246 while (i++ < RECOVERY_CLK_CNT * 2) {
248 /* SCL shouldn't be low here */
249 if (!bri->get_scl(adap)) {
251 "SCL is stuck low, exit recovery\n");
258 bri->set_scl(adap, scl);
259 /* Creating STOP again, see above */
261 /* Honour minimum tsu:sto */
262 ndelay(RECOVERY_NDELAY);
264 /* Honour minimum tf and thd:dat */
265 ndelay(RECOVERY_NDELAY / 2);
268 bri->set_sda(adap, scl);
269 ndelay(RECOVERY_NDELAY / 2);
272 ret = i2c_generic_bus_free(adap);
278 /* If we can't check bus status, assume recovery worked */
279 if (ret == -EOPNOTSUPP)
282 if (bri->unprepare_recovery)
283 bri->unprepare_recovery(adap);
285 pinctrl_select_state(bri->pinctrl, bri->pins_default);
289 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
291 int i2c_recover_bus(struct i2c_adapter *adap)
293 if (!adap->bus_recovery_info)
296 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
297 return adap->bus_recovery_info->recover_bus(adap);
299 EXPORT_SYMBOL_GPL(i2c_recover_bus);
301 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
303 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
304 struct device *dev = &adap->dev;
305 struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
310 * we can't change states without pinctrl, so remove the states if
314 bri->pins_default = NULL;
315 bri->pins_gpio = NULL;
319 if (!bri->pins_default) {
320 bri->pins_default = pinctrl_lookup_state(p,
321 PINCTRL_STATE_DEFAULT);
322 if (IS_ERR(bri->pins_default)) {
323 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
324 bri->pins_default = NULL;
327 if (!bri->pins_gpio) {
328 bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
329 if (IS_ERR(bri->pins_gpio))
330 bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
332 if (IS_ERR(bri->pins_gpio)) {
333 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
334 bri->pins_gpio = NULL;
338 /* for pinctrl state changes, we need all the information */
339 if (bri->pins_default && bri->pins_gpio) {
340 dev_info(dev, "using pinctrl states for GPIO recovery");
343 bri->pins_default = NULL;
344 bri->pins_gpio = NULL;
348 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
350 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
351 struct device *dev = &adap->dev;
352 struct gpio_desc *gpiod;
356 * don't touch the recovery information if the driver is not using
357 * generic SCL recovery
359 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
363 * pins might be taken as GPIO, so we should inform pinctrl about
364 * this and move the state to GPIO
367 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
370 * if there is incomplete or no recovery information, see if generic
371 * GPIO recovery is available
373 if (!bri->scl_gpiod) {
374 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
375 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
377 goto cleanup_pinctrl_state;
379 if (!IS_ERR(gpiod)) {
380 bri->scl_gpiod = gpiod;
381 bri->recover_bus = i2c_generic_scl_recovery;
382 dev_info(dev, "using generic GPIOs for recovery\n");
386 /* SDA GPIOD line is optional, so we care about DEFER only */
387 if (!bri->sda_gpiod) {
389 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
392 gpiod_direction_output(bri->scl_gpiod, 0);
394 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
396 /* Wait a bit in case of a SDA glitch, and then release SCL. */
398 gpiod_direction_output(bri->scl_gpiod, 1);
400 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
402 goto cleanup_pinctrl_state;
405 bri->sda_gpiod = gpiod;
408 cleanup_pinctrl_state:
409 /* change the state of the pins back to their default state */
411 pinctrl_select_state(bri->pinctrl, bri->pins_default);
416 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
418 i2c_gpio_init_pinctrl_recovery(adap);
419 return i2c_gpio_init_generic_recovery(adap);
422 static int i2c_init_recovery(struct i2c_adapter *adap)
424 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
425 bool is_error_level = true;
431 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
432 return -EPROBE_DEFER;
434 if (!bri->recover_bus) {
435 err_str = "no suitable method provided";
436 is_error_level = false;
440 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
441 bri->get_scl = get_scl_gpio_value;
442 bri->set_scl = set_scl_gpio_value;
443 if (bri->sda_gpiod) {
444 bri->get_sda = get_sda_gpio_value;
445 /* FIXME: add proper flag instead of '0' once available */
446 if (gpiod_get_direction(bri->sda_gpiod) == 0)
447 bri->set_sda = set_sda_gpio_value;
449 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
450 /* Generic SCL recovery */
451 if (!bri->set_scl || !bri->get_scl) {
452 err_str = "no {get|set}_scl() found";
455 if (!bri->set_sda && !bri->get_sda) {
456 err_str = "either get_sda() or set_sda() needed";
464 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
466 dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
467 adap->bus_recovery_info = NULL;
472 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
474 struct i2c_adapter *adap = client->adapter;
477 if (!adap->host_notify_domain)
480 if (client->flags & I2C_CLIENT_TEN)
483 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
485 return irq > 0 ? irq : -ENXIO;
488 static int i2c_device_probe(struct device *dev)
490 struct i2c_client *client = i2c_verify_client(dev);
491 struct i2c_driver *driver;
498 client->irq = client->init_irq;
503 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
504 dev_dbg(dev, "Using Host Notify IRQ\n");
505 /* Keep adapter active when Host Notify is required */
506 pm_runtime_get_sync(&client->adapter->dev);
507 irq = i2c_smbus_host_notify_to_irq(client);
508 } else if (dev->of_node) {
509 irq = of_irq_get_byname(dev->of_node, "irq");
510 if (irq == -EINVAL || irq == -ENODATA)
511 irq = of_irq_get(dev->of_node, 0);
512 } else if (ACPI_COMPANION(dev)) {
515 irq = i2c_acpi_get_irq(client, &wake_capable);
516 if (irq > 0 && wake_capable)
517 client->flags |= I2C_CLIENT_WAKE;
519 if (irq == -EPROBE_DEFER) {
521 goto put_sync_adapter;
530 driver = to_i2c_driver(dev->driver);
533 * An I2C ID table is not mandatory, if and only if, a suitable OF
534 * or ACPI ID table is supplied for the probing device.
536 if (!driver->id_table &&
537 !acpi_driver_match_device(dev, dev->driver) &&
538 !i2c_of_match_device(dev->driver->of_match_table, client)) {
540 goto put_sync_adapter;
543 if (client->flags & I2C_CLIENT_WAKE) {
546 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
547 if (wakeirq == -EPROBE_DEFER) {
549 goto put_sync_adapter;
552 device_init_wakeup(&client->dev, true);
554 if (wakeirq > 0 && wakeirq != client->irq)
555 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
556 else if (client->irq > 0)
557 status = dev_pm_set_wake_irq(dev, client->irq);
562 dev_warn(&client->dev, "failed to set up wakeup irq\n");
565 dev_dbg(dev, "probe\n");
567 status = of_clk_set_defaults(dev->of_node, false);
569 goto err_clear_wakeup_irq;
571 do_power_on = !i2c_acpi_waive_d0_probe(dev);
572 status = dev_pm_domain_attach(&client->dev, do_power_on);
574 goto err_clear_wakeup_irq;
576 client->devres_group_id = devres_open_group(&client->dev, NULL,
578 if (!client->devres_group_id) {
580 goto err_detach_pm_domain;
584 status = driver->probe(client);
589 * Note that we are not closing the devres group opened above so
590 * even resources that were attached to the device after probe is
591 * run are released when i2c_device_remove() is executed. This is
592 * needed as some drivers would allocate additional resources,
593 * for example when updating firmware.
597 goto err_release_driver_resources;
601 err_release_driver_resources:
602 devres_release_group(&client->dev, client->devres_group_id);
603 err_detach_pm_domain:
604 dev_pm_domain_detach(&client->dev, do_power_on);
605 err_clear_wakeup_irq:
606 dev_pm_clear_wake_irq(&client->dev);
607 device_init_wakeup(&client->dev, false);
609 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
610 pm_runtime_put_sync(&client->adapter->dev);
615 static void i2c_device_remove(struct device *dev)
617 struct i2c_client *client = to_i2c_client(dev);
618 struct i2c_driver *driver;
620 driver = to_i2c_driver(dev->driver);
621 if (driver->remove) {
622 dev_dbg(dev, "remove\n");
624 driver->remove(client);
627 devres_release_group(&client->dev, client->devres_group_id);
629 dev_pm_domain_detach(&client->dev, true);
631 dev_pm_clear_wake_irq(&client->dev);
632 device_init_wakeup(&client->dev, false);
635 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
636 pm_runtime_put(&client->adapter->dev);
639 static void i2c_device_shutdown(struct device *dev)
641 struct i2c_client *client = i2c_verify_client(dev);
642 struct i2c_driver *driver;
644 if (!client || !dev->driver)
646 driver = to_i2c_driver(dev->driver);
647 if (driver->shutdown)
648 driver->shutdown(client);
649 else if (client->irq > 0)
650 disable_irq(client->irq);
653 static void i2c_client_dev_release(struct device *dev)
655 kfree(to_i2c_client(dev));
659 name_show(struct device *dev, struct device_attribute *attr, char *buf)
661 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
662 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
664 static DEVICE_ATTR_RO(name);
667 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
669 struct i2c_client *client = to_i2c_client(dev);
672 len = of_device_modalias(dev, buf, PAGE_SIZE);
676 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
680 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
682 static DEVICE_ATTR_RO(modalias);
684 static struct attribute *i2c_dev_attrs[] = {
686 /* modalias helps coldplug: modprobe $(cat .../modalias) */
687 &dev_attr_modalias.attr,
690 ATTRIBUTE_GROUPS(i2c_dev);
692 struct bus_type i2c_bus_type = {
694 .match = i2c_device_match,
695 .probe = i2c_device_probe,
696 .remove = i2c_device_remove,
697 .shutdown = i2c_device_shutdown,
699 EXPORT_SYMBOL_GPL(i2c_bus_type);
701 struct device_type i2c_client_type = {
702 .groups = i2c_dev_groups,
703 .uevent = i2c_device_uevent,
704 .release = i2c_client_dev_release,
706 EXPORT_SYMBOL_GPL(i2c_client_type);
710 * i2c_verify_client - return parameter as i2c_client, or NULL
711 * @dev: device, probably from some driver model iterator
713 * When traversing the driver model tree, perhaps using driver model
714 * iterators like @device_for_each_child(), you can't assume very much
715 * about the nodes you find. Use this function to avoid oopses caused
716 * by wrongly treating some non-I2C device as an i2c_client.
718 struct i2c_client *i2c_verify_client(struct device *dev)
720 return (dev->type == &i2c_client_type)
724 EXPORT_SYMBOL(i2c_verify_client);
727 /* Return a unique address which takes the flags of the client into account */
728 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
730 unsigned short addr = client->addr;
732 /* For some client flags, add an arbitrary offset to avoid collisions */
733 if (client->flags & I2C_CLIENT_TEN)
734 addr |= I2C_ADDR_OFFSET_TEN_BIT;
736 if (client->flags & I2C_CLIENT_SLAVE)
737 addr |= I2C_ADDR_OFFSET_SLAVE;
742 /* This is a permissive address validity check, I2C address map constraints
743 * are purposely not enforced, except for the general call address. */
744 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
746 if (flags & I2C_CLIENT_TEN) {
747 /* 10-bit address, all values are valid */
751 /* 7-bit address, reject the general call address */
752 if (addr == 0x00 || addr > 0x7f)
758 /* And this is a strict address validity check, used when probing. If a
759 * device uses a reserved address, then it shouldn't be probed. 7-bit
760 * addressing is assumed, 10-bit address devices are rare and should be
761 * explicitly enumerated. */
762 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
765 * Reserved addresses per I2C specification:
766 * 0x00 General call address / START byte
768 * 0x02 Reserved for different bus format
769 * 0x03 Reserved for future purposes
770 * 0x04-0x07 Hs-mode master code
771 * 0x78-0x7b 10-bit slave addressing
772 * 0x7c-0x7f Reserved for future purposes
774 if (addr < 0x08 || addr > 0x77)
779 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
781 struct i2c_client *client = i2c_verify_client(dev);
782 int addr = *(int *)addrp;
784 if (client && i2c_encode_flags_to_addr(client) == addr)
789 /* walk up mux tree */
790 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
792 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
795 result = device_for_each_child(&adapter->dev, &addr,
796 __i2c_check_addr_busy);
798 if (!result && parent)
799 result = i2c_check_mux_parents(parent, addr);
804 /* recurse down mux tree */
805 static int i2c_check_mux_children(struct device *dev, void *addrp)
809 if (dev->type == &i2c_adapter_type)
810 result = device_for_each_child(dev, addrp,
811 i2c_check_mux_children);
813 result = __i2c_check_addr_busy(dev, addrp);
818 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
820 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
824 result = i2c_check_mux_parents(parent, addr);
827 result = device_for_each_child(&adapter->dev, &addr,
828 i2c_check_mux_children);
834 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
835 * @adapter: Target I2C bus segment
836 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
837 * locks only this branch in the adapter tree
839 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
842 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
846 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
847 * @adapter: Target I2C bus segment
848 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
849 * trylocks only this branch in the adapter tree
851 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
854 return rt_mutex_trylock(&adapter->bus_lock);
858 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
859 * @adapter: Target I2C bus segment
860 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
861 * unlocks only this branch in the adapter tree
863 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
866 rt_mutex_unlock(&adapter->bus_lock);
869 static void i2c_dev_set_name(struct i2c_adapter *adap,
870 struct i2c_client *client,
871 struct i2c_board_info const *info)
873 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
875 if (info && info->dev_name) {
876 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
881 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
885 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
886 i2c_encode_flags_to_addr(client));
889 int i2c_dev_irq_from_resources(const struct resource *resources,
890 unsigned int num_resources)
892 struct irq_data *irqd;
895 for (i = 0; i < num_resources; i++) {
896 const struct resource *r = &resources[i];
898 if (resource_type(r) != IORESOURCE_IRQ)
901 if (r->flags & IORESOURCE_BITS) {
902 irqd = irq_get_irq_data(r->start);
906 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
916 * i2c_new_client_device - instantiate an i2c device
917 * @adap: the adapter managing the device
918 * @info: describes one I2C device; bus_num is ignored
921 * Create an i2c device. Binding is handled through driver model
922 * probe()/remove() methods. A driver may be bound to this device when we
923 * return from this function, or any later moment (e.g. maybe hotplugging will
924 * load the driver module). This call is not appropriate for use by mainboard
925 * initialization logic, which usually runs during an arch_initcall() long
926 * before any i2c_adapter could exist.
928 * This returns the new i2c client, which may be saved for later use with
929 * i2c_unregister_device(); or an ERR_PTR to describe the error.
932 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
934 struct i2c_client *client;
935 bool need_put = false;
938 client = kzalloc(sizeof *client, GFP_KERNEL);
940 return ERR_PTR(-ENOMEM);
942 client->adapter = adap;
944 client->dev.platform_data = info->platform_data;
945 client->flags = info->flags;
946 client->addr = info->addr;
948 client->init_irq = info->irq;
949 if (!client->init_irq)
950 client->init_irq = i2c_dev_irq_from_resources(info->resources,
951 info->num_resources);
953 strscpy(client->name, info->type, sizeof(client->name));
955 status = i2c_check_addr_validity(client->addr, client->flags);
957 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
958 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
962 /* Check for address business */
963 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
967 client->dev.parent = &client->adapter->dev;
968 client->dev.bus = &i2c_bus_type;
969 client->dev.type = &i2c_client_type;
970 client->dev.of_node = of_node_get(info->of_node);
971 client->dev.fwnode = info->fwnode;
973 device_enable_async_suspend(&client->dev);
976 status = device_add_software_node(&client->dev, info->swnode);
979 "Failed to add software node to client %s: %d\n",
980 client->name, status);
981 goto out_err_put_of_node;
985 i2c_dev_set_name(adap, client, info);
986 status = device_register(&client->dev);
988 goto out_remove_swnode;
990 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
991 client->name, dev_name(&client->dev));
996 device_remove_software_node(&client->dev);
999 of_node_put(info->of_node);
1002 "Failed to register i2c client %s at 0x%02x (%d)\n",
1003 client->name, client->addr, status);
1006 put_device(&client->dev);
1009 return ERR_PTR(status);
1011 EXPORT_SYMBOL_GPL(i2c_new_client_device);
1014 * i2c_unregister_device - reverse effect of i2c_new_*_device()
1015 * @client: value returned from i2c_new_*_device()
1016 * Context: can sleep
1018 void i2c_unregister_device(struct i2c_client *client)
1020 if (IS_ERR_OR_NULL(client))
1023 if (client->dev.of_node) {
1024 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1025 of_node_put(client->dev.of_node);
1028 if (ACPI_COMPANION(&client->dev))
1029 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1030 device_remove_software_node(&client->dev);
1031 device_unregister(&client->dev);
1033 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1036 * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1037 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1039 * Look up and return the &struct i2c_client corresponding to the @fwnode.
1040 * If no client can be found, or @fwnode is NULL, this returns NULL.
1042 * The user must call put_device(&client->dev) once done with the i2c client.
1044 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1046 struct i2c_client *client;
1052 dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1056 client = i2c_verify_client(dev);
1062 EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1065 static const struct i2c_device_id dummy_id[] = {
1070 static int dummy_probe(struct i2c_client *client)
1075 static struct i2c_driver dummy_driver = {
1076 .driver.name = "dummy",
1077 .probe = dummy_probe,
1078 .id_table = dummy_id,
1082 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1083 * @adapter: the adapter managing the device
1084 * @address: seven bit address to be used
1085 * Context: can sleep
1087 * This returns an I2C client bound to the "dummy" driver, intended for use
1088 * with devices that consume multiple addresses. Examples of such chips
1089 * include various EEPROMS (like 24c04 and 24c08 models).
1091 * These dummy devices have two main uses. First, most I2C and SMBus calls
1092 * except i2c_transfer() need a client handle; the dummy will be that handle.
1093 * And second, this prevents the specified address from being bound to a
1096 * This returns the new i2c client, which should be saved for later use with
1097 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1099 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1101 struct i2c_board_info info = {
1102 I2C_BOARD_INFO("dummy", address),
1105 return i2c_new_client_device(adapter, &info);
1107 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1109 static void devm_i2c_release_dummy(void *client)
1111 i2c_unregister_device(client);
1115 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1116 * @dev: device the managed resource is bound to
1117 * @adapter: the adapter managing the device
1118 * @address: seven bit address to be used
1119 * Context: can sleep
1121 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1122 * new i2c client or an ERR_PTR in case of an error.
1124 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1125 struct i2c_adapter *adapter,
1128 struct i2c_client *client;
1131 client = i2c_new_dummy_device(adapter, address);
1135 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1137 return ERR_PTR(ret);
1141 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1144 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1145 * and create the associated device
1146 * @client: Handle to the primary client
1147 * @name: Handle to specify which secondary address to get
1148 * @default_addr: Used as a fallback if no secondary address was specified
1149 * Context: can sleep
1151 * I2C clients can be composed of multiple I2C slaves bound together in a single
1152 * component. The I2C client driver then binds to the master I2C slave and needs
1153 * to create I2C dummy clients to communicate with all the other slaves.
1155 * This function creates and returns an I2C dummy client whose I2C address is
1156 * retrieved from the platform firmware based on the given slave name. If no
1157 * address is specified by the firmware default_addr is used.
1159 * On DT-based platforms the address is retrieved from the "reg" property entry
1160 * cell whose "reg-names" value matches the slave name.
1162 * This returns the new i2c client, which should be saved for later use with
1163 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1165 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1169 struct device_node *np = client->dev.of_node;
1170 u32 addr = default_addr;
1174 i = of_property_match_string(np, "reg-names", name);
1176 of_property_read_u32_index(np, "reg", i, &addr);
1179 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1180 return i2c_new_dummy_device(client->adapter, addr);
1182 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1184 /* ------------------------------------------------------------------------- */
1186 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1188 static void i2c_adapter_dev_release(struct device *dev)
1190 struct i2c_adapter *adap = to_i2c_adapter(dev);
1191 complete(&adap->dev_released);
1194 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1196 unsigned int depth = 0;
1198 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1201 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1202 "adapter depth exceeds lockdep subclass limit\n");
1206 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1209 * Let users instantiate I2C devices through sysfs. This can be used when
1210 * platform initialization code doesn't contain the proper data for
1211 * whatever reason. Also useful for drivers that do device detection and
1212 * detection fails, either because the device uses an unexpected address,
1213 * or this is a compatible device with different ID register values.
1215 * Parameter checking may look overzealous, but we really don't want
1216 * the user to provide incorrect parameters.
1219 new_device_store(struct device *dev, struct device_attribute *attr,
1220 const char *buf, size_t count)
1222 struct i2c_adapter *adap = to_i2c_adapter(dev);
1223 struct i2c_board_info info;
1224 struct i2c_client *client;
1228 memset(&info, 0, sizeof(struct i2c_board_info));
1230 blank = strchr(buf, ' ');
1232 dev_err(dev, "%s: Missing parameters\n", "new_device");
1235 if (blank - buf > I2C_NAME_SIZE - 1) {
1236 dev_err(dev, "%s: Invalid device name\n", "new_device");
1239 memcpy(info.type, buf, blank - buf);
1241 /* Parse remaining parameters, reject extra parameters */
1242 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1244 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1247 if (res > 1 && end != '\n') {
1248 dev_err(dev, "%s: Extra parameters\n", "new_device");
1252 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1253 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1254 info.flags |= I2C_CLIENT_TEN;
1257 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1258 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1259 info.flags |= I2C_CLIENT_SLAVE;
1262 client = i2c_new_client_device(adap, &info);
1264 return PTR_ERR(client);
1266 /* Keep track of the added device */
1267 mutex_lock(&adap->userspace_clients_lock);
1268 list_add_tail(&client->detected, &adap->userspace_clients);
1269 mutex_unlock(&adap->userspace_clients_lock);
1270 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1271 info.type, info.addr);
1275 static DEVICE_ATTR_WO(new_device);
1278 * And of course let the users delete the devices they instantiated, if
1279 * they got it wrong. This interface can only be used to delete devices
1280 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1281 * don't delete devices to which some kernel code still has references.
1283 * Parameter checking may look overzealous, but we really don't want
1284 * the user to delete the wrong device.
1287 delete_device_store(struct device *dev, struct device_attribute *attr,
1288 const char *buf, size_t count)
1290 struct i2c_adapter *adap = to_i2c_adapter(dev);
1291 struct i2c_client *client, *next;
1292 unsigned short addr;
1296 /* Parse parameters, reject extra parameters */
1297 res = sscanf(buf, "%hi%c", &addr, &end);
1299 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1302 if (res > 1 && end != '\n') {
1303 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1307 /* Make sure the device was added through sysfs */
1309 mutex_lock_nested(&adap->userspace_clients_lock,
1310 i2c_adapter_depth(adap));
1311 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1313 if (i2c_encode_flags_to_addr(client) == addr) {
1314 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1315 "delete_device", client->name, client->addr);
1317 list_del(&client->detected);
1318 i2c_unregister_device(client);
1323 mutex_unlock(&adap->userspace_clients_lock);
1326 dev_err(dev, "%s: Can't find device in list\n",
1330 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1331 delete_device_store);
1333 static struct attribute *i2c_adapter_attrs[] = {
1334 &dev_attr_name.attr,
1335 &dev_attr_new_device.attr,
1336 &dev_attr_delete_device.attr,
1339 ATTRIBUTE_GROUPS(i2c_adapter);
1341 struct device_type i2c_adapter_type = {
1342 .groups = i2c_adapter_groups,
1343 .release = i2c_adapter_dev_release,
1345 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1348 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1349 * @dev: device, probably from some driver model iterator
1351 * When traversing the driver model tree, perhaps using driver model
1352 * iterators like @device_for_each_child(), you can't assume very much
1353 * about the nodes you find. Use this function to avoid oopses caused
1354 * by wrongly treating some non-I2C device as an i2c_adapter.
1356 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1358 return (dev->type == &i2c_adapter_type)
1359 ? to_i2c_adapter(dev)
1362 EXPORT_SYMBOL(i2c_verify_adapter);
1364 #ifdef CONFIG_I2C_COMPAT
1365 static struct class_compat *i2c_adapter_compat_class;
1368 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1370 struct i2c_devinfo *devinfo;
1372 down_read(&__i2c_board_lock);
1373 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1374 if (devinfo->busnum == adapter->nr &&
1375 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1376 dev_err(&adapter->dev,
1377 "Can't create device at 0x%02x\n",
1378 devinfo->board_info.addr);
1380 up_read(&__i2c_board_lock);
1383 static int i2c_do_add_adapter(struct i2c_driver *driver,
1384 struct i2c_adapter *adap)
1386 /* Detect supported devices on that bus, and instantiate them */
1387 i2c_detect(adap, driver);
1392 static int __process_new_adapter(struct device_driver *d, void *data)
1394 return i2c_do_add_adapter(to_i2c_driver(d), data);
1397 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1398 .lock_bus = i2c_adapter_lock_bus,
1399 .trylock_bus = i2c_adapter_trylock_bus,
1400 .unlock_bus = i2c_adapter_unlock_bus,
1403 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1405 struct irq_domain *domain = adap->host_notify_domain;
1406 irq_hw_number_t hwirq;
1411 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1412 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1414 irq_domain_remove(domain);
1415 adap->host_notify_domain = NULL;
1418 static int i2c_host_notify_irq_map(struct irq_domain *h,
1420 irq_hw_number_t hw_irq_num)
1422 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1427 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1428 .map = i2c_host_notify_irq_map,
1431 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1433 struct irq_domain *domain;
1435 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1438 domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1439 I2C_ADDR_7BITS_COUNT,
1440 &i2c_host_notify_irq_ops, adap);
1444 adap->host_notify_domain = domain;
1450 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1452 * @adap: the adapter
1453 * @addr: the I2C address of the notifying device
1454 * Context: can't sleep
1456 * Helper function to be called from an I2C bus driver's interrupt
1457 * handler. It will schedule the Host Notify IRQ.
1459 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1466 irq = irq_find_mapping(adap->host_notify_domain, addr);
1470 generic_handle_irq_safe(irq);
1474 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1476 static int i2c_register_adapter(struct i2c_adapter *adap)
1480 /* Can't register until after driver model init */
1481 if (WARN_ON(!is_registered)) {
1487 if (WARN(!adap->name[0], "i2c adapter has no name"))
1491 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1495 if (!adap->lock_ops)
1496 adap->lock_ops = &i2c_adapter_lock_ops;
1498 adap->locked_flags = 0;
1499 rt_mutex_init(&adap->bus_lock);
1500 rt_mutex_init(&adap->mux_lock);
1501 mutex_init(&adap->userspace_clients_lock);
1502 INIT_LIST_HEAD(&adap->userspace_clients);
1504 /* Set default timeout to 1 second if not already set */
1505 if (adap->timeout == 0)
1508 /* register soft irqs for Host Notify */
1509 res = i2c_setup_host_notify_irq_domain(adap);
1511 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1516 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1517 adap->dev.bus = &i2c_bus_type;
1518 adap->dev.type = &i2c_adapter_type;
1519 res = device_register(&adap->dev);
1521 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1525 res = i2c_setup_smbus_alert(adap);
1529 device_enable_async_suspend(&adap->dev);
1530 pm_runtime_no_callbacks(&adap->dev);
1531 pm_suspend_ignore_children(&adap->dev, true);
1532 pm_runtime_enable(&adap->dev);
1534 res = i2c_init_recovery(adap);
1535 if (res == -EPROBE_DEFER)
1538 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1540 #ifdef CONFIG_I2C_COMPAT
1541 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1544 dev_warn(&adap->dev,
1545 "Failed to create compatibility class link\n");
1548 /* create pre-declared device nodes */
1549 of_i2c_register_devices(adap);
1550 i2c_acpi_install_space_handler(adap);
1551 i2c_acpi_register_devices(adap);
1553 if (adap->nr < __i2c_first_dynamic_bus_num)
1554 i2c_scan_static_board_info(adap);
1556 /* Notify drivers */
1557 mutex_lock(&core_lock);
1558 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1559 mutex_unlock(&core_lock);
1564 init_completion(&adap->dev_released);
1565 device_unregister(&adap->dev);
1566 wait_for_completion(&adap->dev_released);
1568 mutex_lock(&core_lock);
1569 idr_remove(&i2c_adapter_idr, adap->nr);
1570 mutex_unlock(&core_lock);
1575 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1576 * @adap: the adapter to register (with adap->nr initialized)
1577 * Context: can sleep
1579 * See i2c_add_numbered_adapter() for details.
1581 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1585 mutex_lock(&core_lock);
1586 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1587 mutex_unlock(&core_lock);
1588 if (WARN(id < 0, "couldn't get idr"))
1589 return id == -ENOSPC ? -EBUSY : id;
1591 return i2c_register_adapter(adap);
1595 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1596 * @adapter: the adapter to add
1597 * Context: can sleep
1599 * This routine is used to declare an I2C adapter when its bus number
1600 * doesn't matter or when its bus number is specified by an dt alias.
1601 * Examples of bases when the bus number doesn't matter: I2C adapters
1602 * dynamically added by USB links or PCI plugin cards.
1604 * When this returns zero, a new bus number was allocated and stored
1605 * in adap->nr, and the specified adapter became available for clients.
1606 * Otherwise, a negative errno value is returned.
1608 int i2c_add_adapter(struct i2c_adapter *adapter)
1610 struct device *dev = &adapter->dev;
1614 id = of_alias_get_id(dev->of_node, "i2c");
1617 return __i2c_add_numbered_adapter(adapter);
1621 mutex_lock(&core_lock);
1622 id = idr_alloc(&i2c_adapter_idr, adapter,
1623 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1624 mutex_unlock(&core_lock);
1625 if (WARN(id < 0, "couldn't get idr"))
1630 return i2c_register_adapter(adapter);
1632 EXPORT_SYMBOL(i2c_add_adapter);
1635 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1636 * @adap: the adapter to register (with adap->nr initialized)
1637 * Context: can sleep
1639 * This routine is used to declare an I2C adapter when its bus number
1640 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1641 * or otherwise built in to the system's mainboard, and where i2c_board_info
1642 * is used to properly configure I2C devices.
1644 * If the requested bus number is set to -1, then this function will behave
1645 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1647 * If no devices have pre-been declared for this bus, then be sure to
1648 * register the adapter before any dynamically allocated ones. Otherwise
1649 * the required bus ID may not be available.
1651 * When this returns zero, the specified adapter became available for
1652 * clients using the bus number provided in adap->nr. Also, the table
1653 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1654 * and the appropriate driver model device nodes are created. Otherwise, a
1655 * negative errno value is returned.
1657 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1659 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1660 return i2c_add_adapter(adap);
1662 return __i2c_add_numbered_adapter(adap);
1664 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1666 static void i2c_do_del_adapter(struct i2c_driver *driver,
1667 struct i2c_adapter *adapter)
1669 struct i2c_client *client, *_n;
1671 /* Remove the devices we created ourselves as the result of hardware
1672 * probing (using a driver's detect method) */
1673 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1674 if (client->adapter == adapter) {
1675 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1676 client->name, client->addr);
1677 list_del(&client->detected);
1678 i2c_unregister_device(client);
1683 static int __unregister_client(struct device *dev, void *dummy)
1685 struct i2c_client *client = i2c_verify_client(dev);
1686 if (client && strcmp(client->name, "dummy"))
1687 i2c_unregister_device(client);
1691 static int __unregister_dummy(struct device *dev, void *dummy)
1693 struct i2c_client *client = i2c_verify_client(dev);
1694 i2c_unregister_device(client);
1698 static int __process_removed_adapter(struct device_driver *d, void *data)
1700 i2c_do_del_adapter(to_i2c_driver(d), data);
1705 * i2c_del_adapter - unregister I2C adapter
1706 * @adap: the adapter being unregistered
1707 * Context: can sleep
1709 * This unregisters an I2C adapter which was previously registered
1710 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1712 void i2c_del_adapter(struct i2c_adapter *adap)
1714 struct i2c_adapter *found;
1715 struct i2c_client *client, *next;
1717 /* First make sure that this adapter was ever added */
1718 mutex_lock(&core_lock);
1719 found = idr_find(&i2c_adapter_idr, adap->nr);
1720 mutex_unlock(&core_lock);
1721 if (found != adap) {
1722 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1726 i2c_acpi_remove_space_handler(adap);
1727 /* Tell drivers about this removal */
1728 mutex_lock(&core_lock);
1729 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1730 __process_removed_adapter);
1731 mutex_unlock(&core_lock);
1733 /* Remove devices instantiated from sysfs */
1734 mutex_lock_nested(&adap->userspace_clients_lock,
1735 i2c_adapter_depth(adap));
1736 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1738 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1740 list_del(&client->detected);
1741 i2c_unregister_device(client);
1743 mutex_unlock(&adap->userspace_clients_lock);
1745 /* Detach any active clients. This can't fail, thus we do not
1746 * check the returned value. This is a two-pass process, because
1747 * we can't remove the dummy devices during the first pass: they
1748 * could have been instantiated by real devices wishing to clean
1749 * them up properly, so we give them a chance to do that first. */
1750 device_for_each_child(&adap->dev, NULL, __unregister_client);
1751 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1753 #ifdef CONFIG_I2C_COMPAT
1754 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1758 /* device name is gone after device_unregister */
1759 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1761 pm_runtime_disable(&adap->dev);
1763 i2c_host_notify_irq_teardown(adap);
1765 /* wait until all references to the device are gone
1767 * FIXME: This is old code and should ideally be replaced by an
1768 * alternative which results in decoupling the lifetime of the struct
1769 * device from the i2c_adapter, like spi or netdev do. Any solution
1770 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1772 init_completion(&adap->dev_released);
1773 device_unregister(&adap->dev);
1774 wait_for_completion(&adap->dev_released);
1777 mutex_lock(&core_lock);
1778 idr_remove(&i2c_adapter_idr, adap->nr);
1779 mutex_unlock(&core_lock);
1781 /* Clear the device structure in case this adapter is ever going to be
1783 memset(&adap->dev, 0, sizeof(adap->dev));
1785 EXPORT_SYMBOL(i2c_del_adapter);
1787 static void devm_i2c_del_adapter(void *adapter)
1789 i2c_del_adapter(adapter);
1793 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1794 * @dev: managing device for adding this I2C adapter
1795 * @adapter: the adapter to add
1796 * Context: can sleep
1798 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1799 * but the adapter will be auto deleted on driver detach.
1801 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1805 ret = i2c_add_adapter(adapter);
1809 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1811 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1813 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1815 if (dev_fwnode(dev) == data)
1818 if (dev->parent && dev_fwnode(dev->parent) == data)
1825 * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1826 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1828 * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1829 * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1831 * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1833 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1835 struct i2c_adapter *adapter;
1841 dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1842 i2c_dev_or_parent_fwnode_match);
1846 adapter = i2c_verify_adapter(dev);
1852 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1855 * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1856 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1858 * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1859 * and increment the adapter module's use count. If no adapter can be found,
1860 * or @fwnode is NULL, this returns NULL.
1862 * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1863 * Note that this is different from i2c_find_adapter_by_node().
1865 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1867 struct i2c_adapter *adapter;
1869 adapter = i2c_find_adapter_by_fwnode(fwnode);
1873 if (!try_module_get(adapter->owner)) {
1874 put_device(&adapter->dev);
1880 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1882 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1883 u32 def_val, bool use_def)
1887 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1889 *cur_val_p = def_val;
1891 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1895 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1896 * @dev: The device to scan for I2C timing properties
1897 * @t: the i2c_timings struct to be filled with values
1898 * @use_defaults: bool to use sane defaults derived from the I2C specification
1899 * when properties are not found, otherwise don't update
1901 * Scan the device for the generic I2C properties describing timing parameters
1902 * for the signal and fill the given struct with the results. If a property was
1903 * not found and use_defaults was true, then maximum timings are assumed which
1904 * are derived from the I2C specification. If use_defaults is not used, the
1905 * results will be as before, so drivers can apply their own defaults before
1906 * calling this helper. The latter is mainly intended for avoiding regressions
1907 * of existing drivers which want to switch to this function. New drivers
1908 * almost always should use the defaults.
1910 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1912 bool u = use_defaults;
1915 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1916 I2C_MAX_STANDARD_MODE_FREQ, u);
1918 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1919 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1920 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1922 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1923 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1925 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1926 &t->scl_int_delay_ns, 0, u);
1927 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1929 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1930 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1931 &t->digital_filter_width_ns, 0, u);
1932 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1933 &t->analog_filter_cutoff_freq_hz, 0, u);
1935 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1937 /* ------------------------------------------------------------------------- */
1939 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1943 mutex_lock(&core_lock);
1944 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1945 mutex_unlock(&core_lock);
1949 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1951 static int __process_new_driver(struct device *dev, void *data)
1953 if (dev->type != &i2c_adapter_type)
1955 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1959 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1960 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1963 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1967 /* Can't register until after driver model init */
1968 if (WARN_ON(!is_registered))
1971 /* add the driver to the list of i2c drivers in the driver core */
1972 driver->driver.owner = owner;
1973 driver->driver.bus = &i2c_bus_type;
1974 INIT_LIST_HEAD(&driver->clients);
1976 /* When registration returns, the driver core
1977 * will have called probe() for all matching-but-unbound devices.
1979 res = driver_register(&driver->driver);
1983 pr_debug("driver [%s] registered\n", driver->driver.name);
1985 /* Walk the adapters that are already present */
1986 i2c_for_each_dev(driver, __process_new_driver);
1990 EXPORT_SYMBOL(i2c_register_driver);
1992 static int __process_removed_driver(struct device *dev, void *data)
1994 if (dev->type == &i2c_adapter_type)
1995 i2c_do_del_adapter(data, to_i2c_adapter(dev));
2000 * i2c_del_driver - unregister I2C driver
2001 * @driver: the driver being unregistered
2002 * Context: can sleep
2004 void i2c_del_driver(struct i2c_driver *driver)
2006 i2c_for_each_dev(driver, __process_removed_driver);
2008 driver_unregister(&driver->driver);
2009 pr_debug("driver [%s] unregistered\n", driver->driver.name);
2011 EXPORT_SYMBOL(i2c_del_driver);
2013 /* ------------------------------------------------------------------------- */
2015 struct i2c_cmd_arg {
2020 static int i2c_cmd(struct device *dev, void *_arg)
2022 struct i2c_client *client = i2c_verify_client(dev);
2023 struct i2c_cmd_arg *arg = _arg;
2024 struct i2c_driver *driver;
2026 if (!client || !client->dev.driver)
2029 driver = to_i2c_driver(client->dev.driver);
2030 if (driver->command)
2031 driver->command(client, arg->cmd, arg->arg);
2035 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2037 struct i2c_cmd_arg cmd_arg;
2041 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2043 EXPORT_SYMBOL(i2c_clients_command);
2045 static int __init i2c_init(void)
2049 retval = of_alias_get_highest_id("i2c");
2051 down_write(&__i2c_board_lock);
2052 if (retval >= __i2c_first_dynamic_bus_num)
2053 __i2c_first_dynamic_bus_num = retval + 1;
2054 up_write(&__i2c_board_lock);
2056 retval = bus_register(&i2c_bus_type);
2060 is_registered = true;
2062 #ifdef CONFIG_I2C_COMPAT
2063 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2064 if (!i2c_adapter_compat_class) {
2069 retval = i2c_add_driver(&dummy_driver);
2073 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2074 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2075 if (IS_ENABLED(CONFIG_ACPI))
2076 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2081 #ifdef CONFIG_I2C_COMPAT
2082 class_compat_unregister(i2c_adapter_compat_class);
2085 is_registered = false;
2086 bus_unregister(&i2c_bus_type);
2090 static void __exit i2c_exit(void)
2092 if (IS_ENABLED(CONFIG_ACPI))
2093 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2094 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2095 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2096 i2c_del_driver(&dummy_driver);
2097 #ifdef CONFIG_I2C_COMPAT
2098 class_compat_unregister(i2c_adapter_compat_class);
2100 bus_unregister(&i2c_bus_type);
2101 tracepoint_synchronize_unregister();
2104 /* We must initialize early, because some subsystems register i2c drivers
2105 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2107 postcore_initcall(i2c_init);
2108 module_exit(i2c_exit);
2110 /* ----------------------------------------------------
2111 * the functional interface to the i2c busses.
2112 * ----------------------------------------------------
2115 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2116 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2118 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2120 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2121 err_msg, msg->addr, msg->len,
2122 msg->flags & I2C_M_RD ? "read" : "write");
2126 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2128 const struct i2c_adapter_quirks *q = adap->quirks;
2129 int max_num = q->max_num_msgs, i;
2130 bool do_len_check = true;
2132 if (q->flags & I2C_AQ_COMB) {
2135 /* special checks for combined messages */
2137 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2138 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2140 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2141 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2143 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2144 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2146 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2147 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2149 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2150 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2152 do_len_check = false;
2156 if (i2c_quirk_exceeded(num, max_num))
2157 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2159 for (i = 0; i < num; i++) {
2160 u16 len = msgs[i].len;
2162 if (msgs[i].flags & I2C_M_RD) {
2163 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2164 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2166 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2167 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2169 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2170 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2172 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2173 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2181 * __i2c_transfer - unlocked flavor of i2c_transfer
2182 * @adap: Handle to I2C bus
2183 * @msgs: One or more messages to execute before STOP is issued to
2184 * terminate the operation; each message begins with a START.
2185 * @num: Number of messages to be executed.
2187 * Returns negative errno, else the number of messages executed.
2189 * Adapter lock must be held when calling this function. No debug logging
2190 * takes place. adap->algo->master_xfer existence isn't checked.
2192 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2194 unsigned long orig_jiffies;
2197 if (WARN_ON(!msgs || num < 1))
2200 ret = __i2c_check_suspended(adap);
2204 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2208 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2209 * enabled. This is an efficient way of keeping the for-loop from
2210 * being executed when not needed.
2212 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2214 for (i = 0; i < num; i++)
2215 if (msgs[i].flags & I2C_M_RD)
2216 trace_i2c_read(adap, &msgs[i], i);
2218 trace_i2c_write(adap, &msgs[i], i);
2221 /* Retry automatically on arbitration loss */
2222 orig_jiffies = jiffies;
2223 for (ret = 0, try = 0; try <= adap->retries; try++) {
2224 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2225 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2227 ret = adap->algo->master_xfer(adap, msgs, num);
2231 if (time_after(jiffies, orig_jiffies + adap->timeout))
2235 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2237 for (i = 0; i < ret; i++)
2238 if (msgs[i].flags & I2C_M_RD)
2239 trace_i2c_reply(adap, &msgs[i], i);
2240 trace_i2c_result(adap, num, ret);
2245 EXPORT_SYMBOL(__i2c_transfer);
2248 * i2c_transfer - execute a single or combined I2C message
2249 * @adap: Handle to I2C bus
2250 * @msgs: One or more messages to execute before STOP is issued to
2251 * terminate the operation; each message begins with a START.
2252 * @num: Number of messages to be executed.
2254 * Returns negative errno, else the number of messages executed.
2256 * Note that there is no requirement that each message be sent to
2257 * the same slave address, although that is the most common model.
2259 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2263 if (!adap->algo->master_xfer) {
2264 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2268 /* REVISIT the fault reporting model here is weak:
2270 * - When we get an error after receiving N bytes from a slave,
2271 * there is no way to report "N".
2273 * - When we get a NAK after transmitting N bytes to a slave,
2274 * there is no way to report "N" ... or to let the master
2275 * continue executing the rest of this combined message, if
2276 * that's the appropriate response.
2278 * - When for example "num" is two and we successfully complete
2279 * the first message but get an error part way through the
2280 * second, it's unclear whether that should be reported as
2281 * one (discarding status on the second message) or errno
2282 * (discarding status on the first one).
2284 ret = __i2c_lock_bus_helper(adap);
2288 ret = __i2c_transfer(adap, msgs, num);
2289 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2293 EXPORT_SYMBOL(i2c_transfer);
2296 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2298 * @client: Handle to slave device
2299 * @buf: Where the data is stored
2300 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2301 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2303 * Returns negative errno, or else the number of bytes transferred.
2305 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2306 int count, u16 flags)
2309 struct i2c_msg msg = {
2310 .addr = client->addr,
2311 .flags = flags | (client->flags & I2C_M_TEN),
2316 ret = i2c_transfer(client->adapter, &msg, 1);
2319 * If everything went ok (i.e. 1 msg transferred), return #bytes
2320 * transferred, else error code.
2322 return (ret == 1) ? count : ret;
2324 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2327 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2328 * @client: The device to query
2329 * @id: The queried information
2331 * Returns negative errno on error, zero on success.
2333 int i2c_get_device_id(const struct i2c_client *client,
2334 struct i2c_device_identity *id)
2336 struct i2c_adapter *adap = client->adapter;
2337 union i2c_smbus_data raw_id;
2340 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2343 raw_id.block[0] = 3;
2344 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2345 I2C_SMBUS_READ, client->addr << 1,
2346 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2350 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2351 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2352 id->die_revision = raw_id.block[3] & 0x7;
2355 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2358 * i2c_client_get_device_id - get the driver match table entry of a device
2359 * @client: the device to query. The device must be bound to a driver
2361 * Returns a pointer to the matching entry if found, NULL otherwise.
2363 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2365 const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2367 return i2c_match_id(drv->id_table, client);
2369 EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2371 /* ----------------------------------------------------
2372 * the i2c address scanning function
2373 * Will not work for 10-bit addresses!
2374 * ----------------------------------------------------
2378 * Legacy default probe function, mostly relevant for SMBus. The default
2379 * probe method is a quick write, but it is known to corrupt the 24RF08
2380 * EEPROMs due to a state machine bug, and could also irreversibly
2381 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2382 * we use a short byte read instead. Also, some bus drivers don't implement
2383 * quick write, so we fallback to a byte read in that case too.
2384 * On x86, there is another special case for FSC hardware monitoring chips,
2385 * which want regular byte reads (address 0x73.) Fortunately, these are the
2386 * only known chips using this I2C address on PC hardware.
2387 * Returns 1 if probe succeeded, 0 if not.
2389 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2392 union i2c_smbus_data dummy;
2395 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2396 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2397 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2398 I2C_SMBUS_BYTE_DATA, &dummy);
2401 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2402 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2403 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2404 I2C_SMBUS_QUICK, NULL);
2405 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2406 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2407 I2C_SMBUS_BYTE, &dummy);
2409 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2417 static int i2c_detect_address(struct i2c_client *temp_client,
2418 struct i2c_driver *driver)
2420 struct i2c_board_info info;
2421 struct i2c_adapter *adapter = temp_client->adapter;
2422 int addr = temp_client->addr;
2425 /* Make sure the address is valid */
2426 err = i2c_check_7bit_addr_validity_strict(addr);
2428 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2433 /* Skip if already in use (7 bit, no need to encode flags) */
2434 if (i2c_check_addr_busy(adapter, addr))
2437 /* Make sure there is something at this address */
2438 if (!i2c_default_probe(adapter, addr))
2441 /* Finally call the custom detection function */
2442 memset(&info, 0, sizeof(struct i2c_board_info));
2444 err = driver->detect(temp_client, &info);
2446 /* -ENODEV is returned if the detection fails. We catch it
2447 here as this isn't an error. */
2448 return err == -ENODEV ? 0 : err;
2451 /* Consistency check */
2452 if (info.type[0] == '\0') {
2453 dev_err(&adapter->dev,
2454 "%s detection function provided no name for 0x%x\n",
2455 driver->driver.name, addr);
2457 struct i2c_client *client;
2459 /* Detection succeeded, instantiate the device */
2460 if (adapter->class & I2C_CLASS_DEPRECATED)
2461 dev_warn(&adapter->dev,
2462 "This adapter will soon drop class based instantiation of devices. "
2463 "Please make sure client 0x%02x gets instantiated by other means. "
2464 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2467 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2468 info.type, info.addr);
2469 client = i2c_new_client_device(adapter, &info);
2470 if (!IS_ERR(client))
2471 list_add_tail(&client->detected, &driver->clients);
2473 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2474 info.type, info.addr);
2479 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2481 const unsigned short *address_list;
2482 struct i2c_client *temp_client;
2485 address_list = driver->address_list;
2486 if (!driver->detect || !address_list)
2489 /* Warn that the adapter lost class based instantiation */
2490 if (adapter->class == I2C_CLASS_DEPRECATED) {
2491 dev_dbg(&adapter->dev,
2492 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2493 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2494 driver->driver.name);
2498 /* Stop here if the classes do not match */
2499 if (!(adapter->class & driver->class))
2502 /* Set up a temporary client to help detect callback */
2503 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2506 temp_client->adapter = adapter;
2508 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2509 dev_dbg(&adapter->dev,
2510 "found normal entry for adapter %d, addr 0x%02x\n",
2511 i2c_adapter_id(adapter), address_list[i]);
2512 temp_client->addr = address_list[i];
2513 err = i2c_detect_address(temp_client, driver);
2522 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2524 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2525 I2C_SMBUS_QUICK, NULL) >= 0;
2527 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2530 i2c_new_scanned_device(struct i2c_adapter *adap,
2531 struct i2c_board_info *info,
2532 unsigned short const *addr_list,
2533 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2538 probe = i2c_default_probe;
2540 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2541 /* Check address validity */
2542 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2543 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2548 /* Check address availability (7 bit, no need to encode flags) */
2549 if (i2c_check_addr_busy(adap, addr_list[i])) {
2551 "Address 0x%02x already in use, not probing\n",
2556 /* Test address responsiveness */
2557 if (probe(adap, addr_list[i]))
2561 if (addr_list[i] == I2C_CLIENT_END) {
2562 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2563 return ERR_PTR(-ENODEV);
2566 info->addr = addr_list[i];
2567 return i2c_new_client_device(adap, info);
2569 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2571 struct i2c_adapter *i2c_get_adapter(int nr)
2573 struct i2c_adapter *adapter;
2575 mutex_lock(&core_lock);
2576 adapter = idr_find(&i2c_adapter_idr, nr);
2580 if (try_module_get(adapter->owner))
2581 get_device(&adapter->dev);
2586 mutex_unlock(&core_lock);
2589 EXPORT_SYMBOL(i2c_get_adapter);
2591 void i2c_put_adapter(struct i2c_adapter *adap)
2596 module_put(adap->owner);
2597 /* Should be last, otherwise we risk use-after-free with 'adap' */
2598 put_device(&adap->dev);
2600 EXPORT_SYMBOL(i2c_put_adapter);
2603 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2604 * @msg: the message to be checked
2605 * @threshold: the minimum number of bytes for which using DMA makes sense.
2606 * Should at least be 1.
2608 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2609 * Or a valid pointer to be used with DMA. After use, release it by
2610 * calling i2c_put_dma_safe_msg_buf().
2612 * This function must only be called from process context!
2614 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2616 /* also skip 0-length msgs for bogus thresholds of 0 */
2618 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2620 if (msg->len < threshold || msg->len == 0)
2623 if (msg->flags & I2C_M_DMA_SAFE)
2626 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2627 msg->addr, msg->len);
2629 if (msg->flags & I2C_M_RD)
2630 return kzalloc(msg->len, GFP_KERNEL);
2632 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2634 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2637 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2638 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2639 * @msg: the message which the buffer corresponds to
2640 * @xferred: bool saying if the message was transferred
2642 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2644 if (!buf || buf == msg->buf)
2647 if (xferred && msg->flags & I2C_M_RD)
2648 memcpy(msg->buf, buf, msg->len);
2652 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2654 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2655 MODULE_DESCRIPTION("I2C-Bus main module");
2656 MODULE_LICENSE("GPL");