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;
937 client = kzalloc(sizeof *client, GFP_KERNEL);
939 return ERR_PTR(-ENOMEM);
941 client->adapter = adap;
943 client->dev.platform_data = info->platform_data;
944 client->flags = info->flags;
945 client->addr = info->addr;
947 client->init_irq = info->irq;
948 if (!client->init_irq)
949 client->init_irq = i2c_dev_irq_from_resources(info->resources,
950 info->num_resources);
952 strscpy(client->name, info->type, sizeof(client->name));
954 status = i2c_check_addr_validity(client->addr, client->flags);
956 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
957 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
961 /* Check for address business */
962 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
966 client->dev.parent = &client->adapter->dev;
967 client->dev.bus = &i2c_bus_type;
968 client->dev.type = &i2c_client_type;
969 client->dev.of_node = of_node_get(info->of_node);
970 client->dev.fwnode = info->fwnode;
972 device_enable_async_suspend(&client->dev);
973 i2c_dev_set_name(adap, client, info);
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 status = device_register(&client->dev);
987 goto out_remove_swnode;
989 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
990 client->name, dev_name(&client->dev));
995 device_remove_software_node(&client->dev);
997 of_node_put(info->of_node);
1000 "Failed to register i2c client %s at 0x%02x (%d)\n",
1001 client->name, client->addr, status);
1004 return ERR_PTR(status);
1006 EXPORT_SYMBOL_GPL(i2c_new_client_device);
1009 * i2c_unregister_device - reverse effect of i2c_new_*_device()
1010 * @client: value returned from i2c_new_*_device()
1011 * Context: can sleep
1013 void i2c_unregister_device(struct i2c_client *client)
1015 if (IS_ERR_OR_NULL(client))
1018 if (client->dev.of_node) {
1019 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1020 of_node_put(client->dev.of_node);
1023 if (ACPI_COMPANION(&client->dev))
1024 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1025 device_remove_software_node(&client->dev);
1026 device_unregister(&client->dev);
1028 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1031 * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1032 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1034 * Look up and return the &struct i2c_client corresponding to the @fwnode.
1035 * If no client can be found, or @fwnode is NULL, this returns NULL.
1037 * The user must call put_device(&client->dev) once done with the i2c client.
1039 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1041 struct i2c_client *client;
1047 dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1051 client = i2c_verify_client(dev);
1057 EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1060 static const struct i2c_device_id dummy_id[] = {
1065 static int dummy_probe(struct i2c_client *client)
1070 static struct i2c_driver dummy_driver = {
1071 .driver.name = "dummy",
1072 .probe = dummy_probe,
1073 .id_table = dummy_id,
1077 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1078 * @adapter: the adapter managing the device
1079 * @address: seven bit address to be used
1080 * Context: can sleep
1082 * This returns an I2C client bound to the "dummy" driver, intended for use
1083 * with devices that consume multiple addresses. Examples of such chips
1084 * include various EEPROMS (like 24c04 and 24c08 models).
1086 * These dummy devices have two main uses. First, most I2C and SMBus calls
1087 * except i2c_transfer() need a client handle; the dummy will be that handle.
1088 * And second, this prevents the specified address from being bound to a
1091 * This returns the new i2c client, which should be saved for later use with
1092 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1094 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1096 struct i2c_board_info info = {
1097 I2C_BOARD_INFO("dummy", address),
1100 return i2c_new_client_device(adapter, &info);
1102 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1104 static void devm_i2c_release_dummy(void *client)
1106 i2c_unregister_device(client);
1110 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1111 * @dev: device the managed resource is bound to
1112 * @adapter: the adapter managing the device
1113 * @address: seven bit address to be used
1114 * Context: can sleep
1116 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1117 * new i2c client or an ERR_PTR in case of an error.
1119 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1120 struct i2c_adapter *adapter,
1123 struct i2c_client *client;
1126 client = i2c_new_dummy_device(adapter, address);
1130 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1132 return ERR_PTR(ret);
1136 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1139 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1140 * and create the associated device
1141 * @client: Handle to the primary client
1142 * @name: Handle to specify which secondary address to get
1143 * @default_addr: Used as a fallback if no secondary address was specified
1144 * Context: can sleep
1146 * I2C clients can be composed of multiple I2C slaves bound together in a single
1147 * component. The I2C client driver then binds to the master I2C slave and needs
1148 * to create I2C dummy clients to communicate with all the other slaves.
1150 * This function creates and returns an I2C dummy client whose I2C address is
1151 * retrieved from the platform firmware based on the given slave name. If no
1152 * address is specified by the firmware default_addr is used.
1154 * On DT-based platforms the address is retrieved from the "reg" property entry
1155 * cell whose "reg-names" value matches the slave name.
1157 * This returns the new i2c client, which should be saved for later use with
1158 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1160 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1164 struct device_node *np = client->dev.of_node;
1165 u32 addr = default_addr;
1169 i = of_property_match_string(np, "reg-names", name);
1171 of_property_read_u32_index(np, "reg", i, &addr);
1174 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1175 return i2c_new_dummy_device(client->adapter, addr);
1177 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1179 /* ------------------------------------------------------------------------- */
1181 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1183 static void i2c_adapter_dev_release(struct device *dev)
1185 struct i2c_adapter *adap = to_i2c_adapter(dev);
1186 complete(&adap->dev_released);
1189 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1191 unsigned int depth = 0;
1193 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1196 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1197 "adapter depth exceeds lockdep subclass limit\n");
1201 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1204 * Let users instantiate I2C devices through sysfs. This can be used when
1205 * platform initialization code doesn't contain the proper data for
1206 * whatever reason. Also useful for drivers that do device detection and
1207 * detection fails, either because the device uses an unexpected address,
1208 * or this is a compatible device with different ID register values.
1210 * Parameter checking may look overzealous, but we really don't want
1211 * the user to provide incorrect parameters.
1214 new_device_store(struct device *dev, struct device_attribute *attr,
1215 const char *buf, size_t count)
1217 struct i2c_adapter *adap = to_i2c_adapter(dev);
1218 struct i2c_board_info info;
1219 struct i2c_client *client;
1223 memset(&info, 0, sizeof(struct i2c_board_info));
1225 blank = strchr(buf, ' ');
1227 dev_err(dev, "%s: Missing parameters\n", "new_device");
1230 if (blank - buf > I2C_NAME_SIZE - 1) {
1231 dev_err(dev, "%s: Invalid device name\n", "new_device");
1234 memcpy(info.type, buf, blank - buf);
1236 /* Parse remaining parameters, reject extra parameters */
1237 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1239 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1242 if (res > 1 && end != '\n') {
1243 dev_err(dev, "%s: Extra parameters\n", "new_device");
1247 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1248 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1249 info.flags |= I2C_CLIENT_TEN;
1252 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1253 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1254 info.flags |= I2C_CLIENT_SLAVE;
1257 client = i2c_new_client_device(adap, &info);
1259 return PTR_ERR(client);
1261 /* Keep track of the added device */
1262 mutex_lock(&adap->userspace_clients_lock);
1263 list_add_tail(&client->detected, &adap->userspace_clients);
1264 mutex_unlock(&adap->userspace_clients_lock);
1265 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1266 info.type, info.addr);
1270 static DEVICE_ATTR_WO(new_device);
1273 * And of course let the users delete the devices they instantiated, if
1274 * they got it wrong. This interface can only be used to delete devices
1275 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1276 * don't delete devices to which some kernel code still has references.
1278 * Parameter checking may look overzealous, but we really don't want
1279 * the user to delete the wrong device.
1282 delete_device_store(struct device *dev, struct device_attribute *attr,
1283 const char *buf, size_t count)
1285 struct i2c_adapter *adap = to_i2c_adapter(dev);
1286 struct i2c_client *client, *next;
1287 unsigned short addr;
1291 /* Parse parameters, reject extra parameters */
1292 res = sscanf(buf, "%hi%c", &addr, &end);
1294 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1297 if (res > 1 && end != '\n') {
1298 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1302 /* Make sure the device was added through sysfs */
1304 mutex_lock_nested(&adap->userspace_clients_lock,
1305 i2c_adapter_depth(adap));
1306 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1308 if (i2c_encode_flags_to_addr(client) == addr) {
1309 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1310 "delete_device", client->name, client->addr);
1312 list_del(&client->detected);
1313 i2c_unregister_device(client);
1318 mutex_unlock(&adap->userspace_clients_lock);
1321 dev_err(dev, "%s: Can't find device in list\n",
1325 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1326 delete_device_store);
1328 static struct attribute *i2c_adapter_attrs[] = {
1329 &dev_attr_name.attr,
1330 &dev_attr_new_device.attr,
1331 &dev_attr_delete_device.attr,
1334 ATTRIBUTE_GROUPS(i2c_adapter);
1336 struct device_type i2c_adapter_type = {
1337 .groups = i2c_adapter_groups,
1338 .release = i2c_adapter_dev_release,
1340 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1343 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1344 * @dev: device, probably from some driver model iterator
1346 * When traversing the driver model tree, perhaps using driver model
1347 * iterators like @device_for_each_child(), you can't assume very much
1348 * about the nodes you find. Use this function to avoid oopses caused
1349 * by wrongly treating some non-I2C device as an i2c_adapter.
1351 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1353 return (dev->type == &i2c_adapter_type)
1354 ? to_i2c_adapter(dev)
1357 EXPORT_SYMBOL(i2c_verify_adapter);
1359 #ifdef CONFIG_I2C_COMPAT
1360 static struct class_compat *i2c_adapter_compat_class;
1363 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1365 struct i2c_devinfo *devinfo;
1367 down_read(&__i2c_board_lock);
1368 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1369 if (devinfo->busnum == adapter->nr &&
1370 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1371 dev_err(&adapter->dev,
1372 "Can't create device at 0x%02x\n",
1373 devinfo->board_info.addr);
1375 up_read(&__i2c_board_lock);
1378 static int i2c_do_add_adapter(struct i2c_driver *driver,
1379 struct i2c_adapter *adap)
1381 /* Detect supported devices on that bus, and instantiate them */
1382 i2c_detect(adap, driver);
1387 static int __process_new_adapter(struct device_driver *d, void *data)
1389 return i2c_do_add_adapter(to_i2c_driver(d), data);
1392 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1393 .lock_bus = i2c_adapter_lock_bus,
1394 .trylock_bus = i2c_adapter_trylock_bus,
1395 .unlock_bus = i2c_adapter_unlock_bus,
1398 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1400 struct irq_domain *domain = adap->host_notify_domain;
1401 irq_hw_number_t hwirq;
1406 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1407 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1409 irq_domain_remove(domain);
1410 adap->host_notify_domain = NULL;
1413 static int i2c_host_notify_irq_map(struct irq_domain *h,
1415 irq_hw_number_t hw_irq_num)
1417 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1422 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1423 .map = i2c_host_notify_irq_map,
1426 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1428 struct irq_domain *domain;
1430 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1433 domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1434 I2C_ADDR_7BITS_COUNT,
1435 &i2c_host_notify_irq_ops, adap);
1439 adap->host_notify_domain = domain;
1445 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1447 * @adap: the adapter
1448 * @addr: the I2C address of the notifying device
1449 * Context: can't sleep
1451 * Helper function to be called from an I2C bus driver's interrupt
1452 * handler. It will schedule the Host Notify IRQ.
1454 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1461 irq = irq_find_mapping(adap->host_notify_domain, addr);
1465 generic_handle_irq_safe(irq);
1469 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1471 static int i2c_register_adapter(struct i2c_adapter *adap)
1475 /* Can't register until after driver model init */
1476 if (WARN_ON(!is_registered)) {
1482 if (WARN(!adap->name[0], "i2c adapter has no name"))
1486 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1490 if (!adap->lock_ops)
1491 adap->lock_ops = &i2c_adapter_lock_ops;
1493 adap->locked_flags = 0;
1494 rt_mutex_init(&adap->bus_lock);
1495 rt_mutex_init(&adap->mux_lock);
1496 mutex_init(&adap->userspace_clients_lock);
1497 INIT_LIST_HEAD(&adap->userspace_clients);
1499 /* Set default timeout to 1 second if not already set */
1500 if (adap->timeout == 0)
1503 /* register soft irqs for Host Notify */
1504 res = i2c_setup_host_notify_irq_domain(adap);
1506 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1511 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1512 adap->dev.bus = &i2c_bus_type;
1513 adap->dev.type = &i2c_adapter_type;
1514 res = device_register(&adap->dev);
1516 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1520 res = i2c_setup_smbus_alert(adap);
1524 device_enable_async_suspend(&adap->dev);
1525 pm_runtime_no_callbacks(&adap->dev);
1526 pm_suspend_ignore_children(&adap->dev, true);
1527 pm_runtime_enable(&adap->dev);
1529 res = i2c_init_recovery(adap);
1530 if (res == -EPROBE_DEFER)
1533 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1535 #ifdef CONFIG_I2C_COMPAT
1536 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1539 dev_warn(&adap->dev,
1540 "Failed to create compatibility class link\n");
1543 /* create pre-declared device nodes */
1544 of_i2c_register_devices(adap);
1545 i2c_acpi_install_space_handler(adap);
1546 i2c_acpi_register_devices(adap);
1548 if (adap->nr < __i2c_first_dynamic_bus_num)
1549 i2c_scan_static_board_info(adap);
1551 /* Notify drivers */
1552 mutex_lock(&core_lock);
1553 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1554 mutex_unlock(&core_lock);
1559 init_completion(&adap->dev_released);
1560 device_unregister(&adap->dev);
1561 wait_for_completion(&adap->dev_released);
1563 mutex_lock(&core_lock);
1564 idr_remove(&i2c_adapter_idr, adap->nr);
1565 mutex_unlock(&core_lock);
1570 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1571 * @adap: the adapter to register (with adap->nr initialized)
1572 * Context: can sleep
1574 * See i2c_add_numbered_adapter() for details.
1576 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1580 mutex_lock(&core_lock);
1581 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1582 mutex_unlock(&core_lock);
1583 if (WARN(id < 0, "couldn't get idr"))
1584 return id == -ENOSPC ? -EBUSY : id;
1586 return i2c_register_adapter(adap);
1590 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1591 * @adapter: the adapter to add
1592 * Context: can sleep
1594 * This routine is used to declare an I2C adapter when its bus number
1595 * doesn't matter or when its bus number is specified by an dt alias.
1596 * Examples of bases when the bus number doesn't matter: I2C adapters
1597 * dynamically added by USB links or PCI plugin cards.
1599 * When this returns zero, a new bus number was allocated and stored
1600 * in adap->nr, and the specified adapter became available for clients.
1601 * Otherwise, a negative errno value is returned.
1603 int i2c_add_adapter(struct i2c_adapter *adapter)
1605 struct device *dev = &adapter->dev;
1609 id = of_alias_get_id(dev->of_node, "i2c");
1612 return __i2c_add_numbered_adapter(adapter);
1616 mutex_lock(&core_lock);
1617 id = idr_alloc(&i2c_adapter_idr, adapter,
1618 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1619 mutex_unlock(&core_lock);
1620 if (WARN(id < 0, "couldn't get idr"))
1625 return i2c_register_adapter(adapter);
1627 EXPORT_SYMBOL(i2c_add_adapter);
1630 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1631 * @adap: the adapter to register (with adap->nr initialized)
1632 * Context: can sleep
1634 * This routine is used to declare an I2C adapter when its bus number
1635 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1636 * or otherwise built in to the system's mainboard, and where i2c_board_info
1637 * is used to properly configure I2C devices.
1639 * If the requested bus number is set to -1, then this function will behave
1640 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1642 * If no devices have pre-been declared for this bus, then be sure to
1643 * register the adapter before any dynamically allocated ones. Otherwise
1644 * the required bus ID may not be available.
1646 * When this returns zero, the specified adapter became available for
1647 * clients using the bus number provided in adap->nr. Also, the table
1648 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1649 * and the appropriate driver model device nodes are created. Otherwise, a
1650 * negative errno value is returned.
1652 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1654 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1655 return i2c_add_adapter(adap);
1657 return __i2c_add_numbered_adapter(adap);
1659 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1661 static void i2c_do_del_adapter(struct i2c_driver *driver,
1662 struct i2c_adapter *adapter)
1664 struct i2c_client *client, *_n;
1666 /* Remove the devices we created ourselves as the result of hardware
1667 * probing (using a driver's detect method) */
1668 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1669 if (client->adapter == adapter) {
1670 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1671 client->name, client->addr);
1672 list_del(&client->detected);
1673 i2c_unregister_device(client);
1678 static int __unregister_client(struct device *dev, void *dummy)
1680 struct i2c_client *client = i2c_verify_client(dev);
1681 if (client && strcmp(client->name, "dummy"))
1682 i2c_unregister_device(client);
1686 static int __unregister_dummy(struct device *dev, void *dummy)
1688 struct i2c_client *client = i2c_verify_client(dev);
1689 i2c_unregister_device(client);
1693 static int __process_removed_adapter(struct device_driver *d, void *data)
1695 i2c_do_del_adapter(to_i2c_driver(d), data);
1700 * i2c_del_adapter - unregister I2C adapter
1701 * @adap: the adapter being unregistered
1702 * Context: can sleep
1704 * This unregisters an I2C adapter which was previously registered
1705 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1707 void i2c_del_adapter(struct i2c_adapter *adap)
1709 struct i2c_adapter *found;
1710 struct i2c_client *client, *next;
1712 /* First make sure that this adapter was ever added */
1713 mutex_lock(&core_lock);
1714 found = idr_find(&i2c_adapter_idr, adap->nr);
1715 mutex_unlock(&core_lock);
1716 if (found != adap) {
1717 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1721 i2c_acpi_remove_space_handler(adap);
1722 /* Tell drivers about this removal */
1723 mutex_lock(&core_lock);
1724 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1725 __process_removed_adapter);
1726 mutex_unlock(&core_lock);
1728 /* Remove devices instantiated from sysfs */
1729 mutex_lock_nested(&adap->userspace_clients_lock,
1730 i2c_adapter_depth(adap));
1731 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1733 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1735 list_del(&client->detected);
1736 i2c_unregister_device(client);
1738 mutex_unlock(&adap->userspace_clients_lock);
1740 /* Detach any active clients. This can't fail, thus we do not
1741 * check the returned value. This is a two-pass process, because
1742 * we can't remove the dummy devices during the first pass: they
1743 * could have been instantiated by real devices wishing to clean
1744 * them up properly, so we give them a chance to do that first. */
1745 device_for_each_child(&adap->dev, NULL, __unregister_client);
1746 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1748 #ifdef CONFIG_I2C_COMPAT
1749 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1753 /* device name is gone after device_unregister */
1754 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1756 pm_runtime_disable(&adap->dev);
1758 i2c_host_notify_irq_teardown(adap);
1760 /* wait until all references to the device are gone
1762 * FIXME: This is old code and should ideally be replaced by an
1763 * alternative which results in decoupling the lifetime of the struct
1764 * device from the i2c_adapter, like spi or netdev do. Any solution
1765 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1767 init_completion(&adap->dev_released);
1768 device_unregister(&adap->dev);
1769 wait_for_completion(&adap->dev_released);
1772 mutex_lock(&core_lock);
1773 idr_remove(&i2c_adapter_idr, adap->nr);
1774 mutex_unlock(&core_lock);
1776 /* Clear the device structure in case this adapter is ever going to be
1778 memset(&adap->dev, 0, sizeof(adap->dev));
1780 EXPORT_SYMBOL(i2c_del_adapter);
1782 static void devm_i2c_del_adapter(void *adapter)
1784 i2c_del_adapter(adapter);
1788 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1789 * @dev: managing device for adding this I2C adapter
1790 * @adapter: the adapter to add
1791 * Context: can sleep
1793 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1794 * but the adapter will be auto deleted on driver detach.
1796 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1800 ret = i2c_add_adapter(adapter);
1804 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1806 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1808 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1810 if (dev_fwnode(dev) == data)
1813 if (dev->parent && dev_fwnode(dev->parent) == data)
1820 * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1821 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1823 * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1824 * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1826 * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1828 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1830 struct i2c_adapter *adapter;
1836 dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1837 i2c_dev_or_parent_fwnode_match);
1841 adapter = i2c_verify_adapter(dev);
1847 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1850 * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1851 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1853 * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1854 * and increment the adapter module's use count. If no adapter can be found,
1855 * or @fwnode is NULL, this returns NULL.
1857 * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1858 * Note that this is different from i2c_find_adapter_by_node().
1860 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1862 struct i2c_adapter *adapter;
1864 adapter = i2c_find_adapter_by_fwnode(fwnode);
1868 if (!try_module_get(adapter->owner)) {
1869 put_device(&adapter->dev);
1875 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1877 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1878 u32 def_val, bool use_def)
1882 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1884 *cur_val_p = def_val;
1886 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1890 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1891 * @dev: The device to scan for I2C timing properties
1892 * @t: the i2c_timings struct to be filled with values
1893 * @use_defaults: bool to use sane defaults derived from the I2C specification
1894 * when properties are not found, otherwise don't update
1896 * Scan the device for the generic I2C properties describing timing parameters
1897 * for the signal and fill the given struct with the results. If a property was
1898 * not found and use_defaults was true, then maximum timings are assumed which
1899 * are derived from the I2C specification. If use_defaults is not used, the
1900 * results will be as before, so drivers can apply their own defaults before
1901 * calling this helper. The latter is mainly intended for avoiding regressions
1902 * of existing drivers which want to switch to this function. New drivers
1903 * almost always should use the defaults.
1905 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1907 bool u = use_defaults;
1910 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1911 I2C_MAX_STANDARD_MODE_FREQ, u);
1913 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1914 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1915 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1917 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1918 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1920 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1921 &t->scl_int_delay_ns, 0, u);
1922 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1924 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1925 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1926 &t->digital_filter_width_ns, 0, u);
1927 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1928 &t->analog_filter_cutoff_freq_hz, 0, u);
1930 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1932 /* ------------------------------------------------------------------------- */
1934 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1938 mutex_lock(&core_lock);
1939 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1940 mutex_unlock(&core_lock);
1944 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1946 static int __process_new_driver(struct device *dev, void *data)
1948 if (dev->type != &i2c_adapter_type)
1950 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1954 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1955 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1958 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1962 /* Can't register until after driver model init */
1963 if (WARN_ON(!is_registered))
1966 /* add the driver to the list of i2c drivers in the driver core */
1967 driver->driver.owner = owner;
1968 driver->driver.bus = &i2c_bus_type;
1969 INIT_LIST_HEAD(&driver->clients);
1971 /* When registration returns, the driver core
1972 * will have called probe() for all matching-but-unbound devices.
1974 res = driver_register(&driver->driver);
1978 pr_debug("driver [%s] registered\n", driver->driver.name);
1980 /* Walk the adapters that are already present */
1981 i2c_for_each_dev(driver, __process_new_driver);
1985 EXPORT_SYMBOL(i2c_register_driver);
1987 static int __process_removed_driver(struct device *dev, void *data)
1989 if (dev->type == &i2c_adapter_type)
1990 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1995 * i2c_del_driver - unregister I2C driver
1996 * @driver: the driver being unregistered
1997 * Context: can sleep
1999 void i2c_del_driver(struct i2c_driver *driver)
2001 i2c_for_each_dev(driver, __process_removed_driver);
2003 driver_unregister(&driver->driver);
2004 pr_debug("driver [%s] unregistered\n", driver->driver.name);
2006 EXPORT_SYMBOL(i2c_del_driver);
2008 /* ------------------------------------------------------------------------- */
2010 struct i2c_cmd_arg {
2015 static int i2c_cmd(struct device *dev, void *_arg)
2017 struct i2c_client *client = i2c_verify_client(dev);
2018 struct i2c_cmd_arg *arg = _arg;
2019 struct i2c_driver *driver;
2021 if (!client || !client->dev.driver)
2024 driver = to_i2c_driver(client->dev.driver);
2025 if (driver->command)
2026 driver->command(client, arg->cmd, arg->arg);
2030 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2032 struct i2c_cmd_arg cmd_arg;
2036 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2038 EXPORT_SYMBOL(i2c_clients_command);
2040 static int __init i2c_init(void)
2044 retval = of_alias_get_highest_id("i2c");
2046 down_write(&__i2c_board_lock);
2047 if (retval >= __i2c_first_dynamic_bus_num)
2048 __i2c_first_dynamic_bus_num = retval + 1;
2049 up_write(&__i2c_board_lock);
2051 retval = bus_register(&i2c_bus_type);
2055 is_registered = true;
2057 #ifdef CONFIG_I2C_COMPAT
2058 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2059 if (!i2c_adapter_compat_class) {
2064 retval = i2c_add_driver(&dummy_driver);
2068 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2069 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2070 if (IS_ENABLED(CONFIG_ACPI))
2071 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2076 #ifdef CONFIG_I2C_COMPAT
2077 class_compat_unregister(i2c_adapter_compat_class);
2080 is_registered = false;
2081 bus_unregister(&i2c_bus_type);
2085 static void __exit i2c_exit(void)
2087 if (IS_ENABLED(CONFIG_ACPI))
2088 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2089 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2090 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2091 i2c_del_driver(&dummy_driver);
2092 #ifdef CONFIG_I2C_COMPAT
2093 class_compat_unregister(i2c_adapter_compat_class);
2095 bus_unregister(&i2c_bus_type);
2096 tracepoint_synchronize_unregister();
2099 /* We must initialize early, because some subsystems register i2c drivers
2100 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2102 postcore_initcall(i2c_init);
2103 module_exit(i2c_exit);
2105 /* ----------------------------------------------------
2106 * the functional interface to the i2c busses.
2107 * ----------------------------------------------------
2110 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2111 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2113 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2115 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2116 err_msg, msg->addr, msg->len,
2117 msg->flags & I2C_M_RD ? "read" : "write");
2121 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2123 const struct i2c_adapter_quirks *q = adap->quirks;
2124 int max_num = q->max_num_msgs, i;
2125 bool do_len_check = true;
2127 if (q->flags & I2C_AQ_COMB) {
2130 /* special checks for combined messages */
2132 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2133 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2135 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2136 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2138 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2139 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2141 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2142 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2144 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2145 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2147 do_len_check = false;
2151 if (i2c_quirk_exceeded(num, max_num))
2152 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2154 for (i = 0; i < num; i++) {
2155 u16 len = msgs[i].len;
2157 if (msgs[i].flags & I2C_M_RD) {
2158 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2159 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2161 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2162 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2164 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2165 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2167 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2168 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2176 * __i2c_transfer - unlocked flavor of i2c_transfer
2177 * @adap: Handle to I2C bus
2178 * @msgs: One or more messages to execute before STOP is issued to
2179 * terminate the operation; each message begins with a START.
2180 * @num: Number of messages to be executed.
2182 * Returns negative errno, else the number of messages executed.
2184 * Adapter lock must be held when calling this function. No debug logging
2185 * takes place. adap->algo->master_xfer existence isn't checked.
2187 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2189 unsigned long orig_jiffies;
2192 if (WARN_ON(!msgs || num < 1))
2195 ret = __i2c_check_suspended(adap);
2199 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2203 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2204 * enabled. This is an efficient way of keeping the for-loop from
2205 * being executed when not needed.
2207 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2209 for (i = 0; i < num; i++)
2210 if (msgs[i].flags & I2C_M_RD)
2211 trace_i2c_read(adap, &msgs[i], i);
2213 trace_i2c_write(adap, &msgs[i], i);
2216 /* Retry automatically on arbitration loss */
2217 orig_jiffies = jiffies;
2218 for (ret = 0, try = 0; try <= adap->retries; try++) {
2219 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2220 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2222 ret = adap->algo->master_xfer(adap, msgs, num);
2226 if (time_after(jiffies, orig_jiffies + adap->timeout))
2230 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2232 for (i = 0; i < ret; i++)
2233 if (msgs[i].flags & I2C_M_RD)
2234 trace_i2c_reply(adap, &msgs[i], i);
2235 trace_i2c_result(adap, num, ret);
2240 EXPORT_SYMBOL(__i2c_transfer);
2243 * i2c_transfer - execute a single or combined I2C message
2244 * @adap: Handle to I2C bus
2245 * @msgs: One or more messages to execute before STOP is issued to
2246 * terminate the operation; each message begins with a START.
2247 * @num: Number of messages to be executed.
2249 * Returns negative errno, else the number of messages executed.
2251 * Note that there is no requirement that each message be sent to
2252 * the same slave address, although that is the most common model.
2254 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2258 if (!adap->algo->master_xfer) {
2259 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2263 /* REVISIT the fault reporting model here is weak:
2265 * - When we get an error after receiving N bytes from a slave,
2266 * there is no way to report "N".
2268 * - When we get a NAK after transmitting N bytes to a slave,
2269 * there is no way to report "N" ... or to let the master
2270 * continue executing the rest of this combined message, if
2271 * that's the appropriate response.
2273 * - When for example "num" is two and we successfully complete
2274 * the first message but get an error part way through the
2275 * second, it's unclear whether that should be reported as
2276 * one (discarding status on the second message) or errno
2277 * (discarding status on the first one).
2279 ret = __i2c_lock_bus_helper(adap);
2283 ret = __i2c_transfer(adap, msgs, num);
2284 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2288 EXPORT_SYMBOL(i2c_transfer);
2291 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2293 * @client: Handle to slave device
2294 * @buf: Where the data is stored
2295 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2296 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2298 * Returns negative errno, or else the number of bytes transferred.
2300 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2301 int count, u16 flags)
2304 struct i2c_msg msg = {
2305 .addr = client->addr,
2306 .flags = flags | (client->flags & I2C_M_TEN),
2311 ret = i2c_transfer(client->adapter, &msg, 1);
2314 * If everything went ok (i.e. 1 msg transferred), return #bytes
2315 * transferred, else error code.
2317 return (ret == 1) ? count : ret;
2319 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2322 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2323 * @client: The device to query
2324 * @id: The queried information
2326 * Returns negative errno on error, zero on success.
2328 int i2c_get_device_id(const struct i2c_client *client,
2329 struct i2c_device_identity *id)
2331 struct i2c_adapter *adap = client->adapter;
2332 union i2c_smbus_data raw_id;
2335 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2338 raw_id.block[0] = 3;
2339 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2340 I2C_SMBUS_READ, client->addr << 1,
2341 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2345 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2346 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2347 id->die_revision = raw_id.block[3] & 0x7;
2350 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2353 * i2c_client_get_device_id - get the driver match table entry of a device
2354 * @client: the device to query. The device must be bound to a driver
2356 * Returns a pointer to the matching entry if found, NULL otherwise.
2358 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2360 const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2362 return i2c_match_id(drv->id_table, client);
2364 EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2366 /* ----------------------------------------------------
2367 * the i2c address scanning function
2368 * Will not work for 10-bit addresses!
2369 * ----------------------------------------------------
2373 * Legacy default probe function, mostly relevant for SMBus. The default
2374 * probe method is a quick write, but it is known to corrupt the 24RF08
2375 * EEPROMs due to a state machine bug, and could also irreversibly
2376 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2377 * we use a short byte read instead. Also, some bus drivers don't implement
2378 * quick write, so we fallback to a byte read in that case too.
2379 * On x86, there is another special case for FSC hardware monitoring chips,
2380 * which want regular byte reads (address 0x73.) Fortunately, these are the
2381 * only known chips using this I2C address on PC hardware.
2382 * Returns 1 if probe succeeded, 0 if not.
2384 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2387 union i2c_smbus_data dummy;
2390 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2391 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2392 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2393 I2C_SMBUS_BYTE_DATA, &dummy);
2396 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2397 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2398 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2399 I2C_SMBUS_QUICK, NULL);
2400 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2401 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2402 I2C_SMBUS_BYTE, &dummy);
2404 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2412 static int i2c_detect_address(struct i2c_client *temp_client,
2413 struct i2c_driver *driver)
2415 struct i2c_board_info info;
2416 struct i2c_adapter *adapter = temp_client->adapter;
2417 int addr = temp_client->addr;
2420 /* Make sure the address is valid */
2421 err = i2c_check_7bit_addr_validity_strict(addr);
2423 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2428 /* Skip if already in use (7 bit, no need to encode flags) */
2429 if (i2c_check_addr_busy(adapter, addr))
2432 /* Make sure there is something at this address */
2433 if (!i2c_default_probe(adapter, addr))
2436 /* Finally call the custom detection function */
2437 memset(&info, 0, sizeof(struct i2c_board_info));
2439 err = driver->detect(temp_client, &info);
2441 /* -ENODEV is returned if the detection fails. We catch it
2442 here as this isn't an error. */
2443 return err == -ENODEV ? 0 : err;
2446 /* Consistency check */
2447 if (info.type[0] == '\0') {
2448 dev_err(&adapter->dev,
2449 "%s detection function provided no name for 0x%x\n",
2450 driver->driver.name, addr);
2452 struct i2c_client *client;
2454 /* Detection succeeded, instantiate the device */
2455 if (adapter->class & I2C_CLASS_DEPRECATED)
2456 dev_warn(&adapter->dev,
2457 "This adapter will soon drop class based instantiation of devices. "
2458 "Please make sure client 0x%02x gets instantiated by other means. "
2459 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2462 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2463 info.type, info.addr);
2464 client = i2c_new_client_device(adapter, &info);
2465 if (!IS_ERR(client))
2466 list_add_tail(&client->detected, &driver->clients);
2468 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2469 info.type, info.addr);
2474 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2476 const unsigned short *address_list;
2477 struct i2c_client *temp_client;
2480 address_list = driver->address_list;
2481 if (!driver->detect || !address_list)
2484 /* Warn that the adapter lost class based instantiation */
2485 if (adapter->class == I2C_CLASS_DEPRECATED) {
2486 dev_dbg(&adapter->dev,
2487 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2488 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2489 driver->driver.name);
2493 /* Stop here if the classes do not match */
2494 if (!(adapter->class & driver->class))
2497 /* Set up a temporary client to help detect callback */
2498 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2501 temp_client->adapter = adapter;
2503 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2504 dev_dbg(&adapter->dev,
2505 "found normal entry for adapter %d, addr 0x%02x\n",
2506 i2c_adapter_id(adapter), address_list[i]);
2507 temp_client->addr = address_list[i];
2508 err = i2c_detect_address(temp_client, driver);
2517 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2519 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2520 I2C_SMBUS_QUICK, NULL) >= 0;
2522 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2525 i2c_new_scanned_device(struct i2c_adapter *adap,
2526 struct i2c_board_info *info,
2527 unsigned short const *addr_list,
2528 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2533 probe = i2c_default_probe;
2535 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2536 /* Check address validity */
2537 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2538 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2543 /* Check address availability (7 bit, no need to encode flags) */
2544 if (i2c_check_addr_busy(adap, addr_list[i])) {
2546 "Address 0x%02x already in use, not probing\n",
2551 /* Test address responsiveness */
2552 if (probe(adap, addr_list[i]))
2556 if (addr_list[i] == I2C_CLIENT_END) {
2557 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2558 return ERR_PTR(-ENODEV);
2561 info->addr = addr_list[i];
2562 return i2c_new_client_device(adap, info);
2564 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2566 struct i2c_adapter *i2c_get_adapter(int nr)
2568 struct i2c_adapter *adapter;
2570 mutex_lock(&core_lock);
2571 adapter = idr_find(&i2c_adapter_idr, nr);
2575 if (try_module_get(adapter->owner))
2576 get_device(&adapter->dev);
2581 mutex_unlock(&core_lock);
2584 EXPORT_SYMBOL(i2c_get_adapter);
2586 void i2c_put_adapter(struct i2c_adapter *adap)
2591 module_put(adap->owner);
2592 /* Should be last, otherwise we risk use-after-free with 'adap' */
2593 put_device(&adap->dev);
2595 EXPORT_SYMBOL(i2c_put_adapter);
2598 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2599 * @msg: the message to be checked
2600 * @threshold: the minimum number of bytes for which using DMA makes sense.
2601 * Should at least be 1.
2603 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2604 * Or a valid pointer to be used with DMA. After use, release it by
2605 * calling i2c_put_dma_safe_msg_buf().
2607 * This function must only be called from process context!
2609 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2611 /* also skip 0-length msgs for bogus thresholds of 0 */
2613 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2615 if (msg->len < threshold || msg->len == 0)
2618 if (msg->flags & I2C_M_DMA_SAFE)
2621 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2622 msg->addr, msg->len);
2624 if (msg->flags & I2C_M_RD)
2625 return kzalloc(msg->len, GFP_KERNEL);
2627 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2629 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2632 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2633 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2634 * @msg: the message which the buffer corresponds to
2635 * @xferred: bool saying if the message was transferred
2637 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2639 if (!buf || buf == msg->buf)
2642 if (xferred && msg->flags & I2C_M_RD)
2643 memcpy(msg->buf, buf, msg->len);
2647 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2649 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2650 MODULE_DESCRIPTION("I2C-Bus main module");
2651 MODULE_LICENSE("GPL");