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 static int i2c_device_match(struct device *dev, struct device_driver *drv)
119 struct i2c_client *client = i2c_verify_client(dev);
120 struct i2c_driver *driver;
123 /* Attempt an OF style match */
124 if (i2c_of_match_device(drv->of_match_table, client))
127 /* Then ACPI style match */
128 if (acpi_driver_match_device(dev, drv))
131 driver = to_i2c_driver(drv);
133 /* Finally an I2C match */
134 if (i2c_match_id(driver->id_table, client))
140 static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
142 const struct i2c_client *client = to_i2c_client(dev);
145 rc = of_device_uevent_modalias(dev, env);
149 rc = acpi_device_uevent_modalias(dev, env);
153 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
156 /* i2c bus recovery routines */
157 static int get_scl_gpio_value(struct i2c_adapter *adap)
159 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
162 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
164 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
167 static int get_sda_gpio_value(struct i2c_adapter *adap)
169 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
172 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
174 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
177 static int i2c_generic_bus_free(struct i2c_adapter *adap)
179 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
180 int ret = -EOPNOTSUPP;
182 if (bri->get_bus_free)
183 ret = bri->get_bus_free(adap);
184 else if (bri->get_sda)
185 ret = bri->get_sda(adap);
190 return ret ? 0 : -EBUSY;
194 * We are generating clock pulses. ndelay() determines durating of clk pulses.
195 * We will generate clock with rate 100 KHz and so duration of both clock levels
196 * is: delay in ns = (10^6 / 100) / 2
198 #define RECOVERY_NDELAY 5000
199 #define RECOVERY_CLK_CNT 9
201 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
203 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
204 int i = 0, scl = 1, ret = 0;
206 if (bri->prepare_recovery)
207 bri->prepare_recovery(adap);
209 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
212 * If we can set SDA, we will always create a STOP to ensure additional
213 * pulses will do no harm. This is achieved by letting SDA follow SCL
214 * half a cycle later. Check the 'incomplete_write_byte' fault injector
215 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
216 * here for simplicity.
218 bri->set_scl(adap, scl);
219 ndelay(RECOVERY_NDELAY);
221 bri->set_sda(adap, scl);
222 ndelay(RECOVERY_NDELAY / 2);
225 * By this time SCL is high, as we need to give 9 falling-rising edges
227 while (i++ < RECOVERY_CLK_CNT * 2) {
229 /* SCL shouldn't be low here */
230 if (!bri->get_scl(adap)) {
232 "SCL is stuck low, exit recovery\n");
239 bri->set_scl(adap, scl);
240 /* Creating STOP again, see above */
242 /* Honour minimum tsu:sto */
243 ndelay(RECOVERY_NDELAY);
245 /* Honour minimum tf and thd:dat */
246 ndelay(RECOVERY_NDELAY / 2);
249 bri->set_sda(adap, scl);
250 ndelay(RECOVERY_NDELAY / 2);
253 ret = i2c_generic_bus_free(adap);
259 /* If we can't check bus status, assume recovery worked */
260 if (ret == -EOPNOTSUPP)
263 if (bri->unprepare_recovery)
264 bri->unprepare_recovery(adap);
266 pinctrl_select_state(bri->pinctrl, bri->pins_default);
270 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
272 int i2c_recover_bus(struct i2c_adapter *adap)
274 if (!adap->bus_recovery_info)
277 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
278 return adap->bus_recovery_info->recover_bus(adap);
280 EXPORT_SYMBOL_GPL(i2c_recover_bus);
282 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
284 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
285 struct device *dev = &adap->dev;
286 struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
291 * we can't change states without pinctrl, so remove the states if
295 bri->pins_default = NULL;
296 bri->pins_gpio = NULL;
300 if (!bri->pins_default) {
301 bri->pins_default = pinctrl_lookup_state(p,
302 PINCTRL_STATE_DEFAULT);
303 if (IS_ERR(bri->pins_default)) {
304 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
305 bri->pins_default = NULL;
308 if (!bri->pins_gpio) {
309 bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
310 if (IS_ERR(bri->pins_gpio))
311 bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
313 if (IS_ERR(bri->pins_gpio)) {
314 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
315 bri->pins_gpio = NULL;
319 /* for pinctrl state changes, we need all the information */
320 if (bri->pins_default && bri->pins_gpio) {
321 dev_info(dev, "using pinctrl states for GPIO recovery");
324 bri->pins_default = NULL;
325 bri->pins_gpio = NULL;
329 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
331 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
332 struct device *dev = &adap->dev;
333 struct gpio_desc *gpiod;
337 * don't touch the recovery information if the driver is not using
338 * generic SCL recovery
340 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
344 * pins might be taken as GPIO, so we should inform pinctrl about
345 * this and move the state to GPIO
348 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
351 * if there is incomplete or no recovery information, see if generic
352 * GPIO recovery is available
354 if (!bri->scl_gpiod) {
355 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
356 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
358 goto cleanup_pinctrl_state;
360 if (!IS_ERR(gpiod)) {
361 bri->scl_gpiod = gpiod;
362 bri->recover_bus = i2c_generic_scl_recovery;
363 dev_info(dev, "using generic GPIOs for recovery\n");
367 /* SDA GPIOD line is optional, so we care about DEFER only */
368 if (!bri->sda_gpiod) {
370 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
373 gpiod_direction_output(bri->scl_gpiod, 0);
375 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
377 /* Wait a bit in case of a SDA glitch, and then release SCL. */
379 gpiod_direction_output(bri->scl_gpiod, 1);
381 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
383 goto cleanup_pinctrl_state;
386 bri->sda_gpiod = gpiod;
389 cleanup_pinctrl_state:
390 /* change the state of the pins back to their default state */
392 pinctrl_select_state(bri->pinctrl, bri->pins_default);
397 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
399 i2c_gpio_init_pinctrl_recovery(adap);
400 return i2c_gpio_init_generic_recovery(adap);
403 static int i2c_init_recovery(struct i2c_adapter *adap)
405 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
406 bool is_error_level = true;
412 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
413 return -EPROBE_DEFER;
415 if (!bri->recover_bus) {
416 err_str = "no suitable method provided";
417 is_error_level = false;
421 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
422 bri->get_scl = get_scl_gpio_value;
423 bri->set_scl = set_scl_gpio_value;
424 if (bri->sda_gpiod) {
425 bri->get_sda = get_sda_gpio_value;
426 /* FIXME: add proper flag instead of '0' once available */
427 if (gpiod_get_direction(bri->sda_gpiod) == 0)
428 bri->set_sda = set_sda_gpio_value;
430 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
431 /* Generic SCL recovery */
432 if (!bri->set_scl || !bri->get_scl) {
433 err_str = "no {get|set}_scl() found";
436 if (!bri->set_sda && !bri->get_sda) {
437 err_str = "either get_sda() or set_sda() needed";
445 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
447 dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
448 adap->bus_recovery_info = NULL;
453 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
455 struct i2c_adapter *adap = client->adapter;
458 if (!adap->host_notify_domain)
461 if (client->flags & I2C_CLIENT_TEN)
464 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
466 return irq > 0 ? irq : -ENXIO;
469 static int i2c_device_probe(struct device *dev)
471 struct i2c_client *client = i2c_verify_client(dev);
472 struct i2c_driver *driver;
479 client->irq = client->init_irq;
484 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
485 dev_dbg(dev, "Using Host Notify IRQ\n");
486 /* Keep adapter active when Host Notify is required */
487 pm_runtime_get_sync(&client->adapter->dev);
488 irq = i2c_smbus_host_notify_to_irq(client);
489 } else if (dev->of_node) {
490 irq = of_irq_get_byname(dev->of_node, "irq");
491 if (irq == -EINVAL || irq == -ENODATA)
492 irq = of_irq_get(dev->of_node, 0);
493 } else if (ACPI_COMPANION(dev)) {
496 irq = i2c_acpi_get_irq(client, &wake_capable);
497 if (irq > 0 && wake_capable)
498 client->flags |= I2C_CLIENT_WAKE;
500 if (irq == -EPROBE_DEFER) {
502 goto put_sync_adapter;
511 driver = to_i2c_driver(dev->driver);
514 * An I2C ID table is not mandatory, if and only if, a suitable OF
515 * or ACPI ID table is supplied for the probing device.
517 if (!driver->id_table &&
518 !acpi_driver_match_device(dev, dev->driver) &&
519 !i2c_of_match_device(dev->driver->of_match_table, client)) {
521 goto put_sync_adapter;
524 if (client->flags & I2C_CLIENT_WAKE) {
527 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
528 if (wakeirq == -EPROBE_DEFER) {
530 goto put_sync_adapter;
533 device_init_wakeup(&client->dev, true);
535 if (wakeirq > 0 && wakeirq != client->irq)
536 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
537 else if (client->irq > 0)
538 status = dev_pm_set_wake_irq(dev, client->irq);
543 dev_warn(&client->dev, "failed to set up wakeup irq\n");
546 dev_dbg(dev, "probe\n");
548 status = of_clk_set_defaults(dev->of_node, false);
550 goto err_clear_wakeup_irq;
552 do_power_on = !i2c_acpi_waive_d0_probe(dev);
553 status = dev_pm_domain_attach(&client->dev, do_power_on);
555 goto err_clear_wakeup_irq;
557 client->devres_group_id = devres_open_group(&client->dev, NULL,
559 if (!client->devres_group_id) {
561 goto err_detach_pm_domain;
565 status = driver->probe(client);
570 * Note that we are not closing the devres group opened above so
571 * even resources that were attached to the device after probe is
572 * run are released when i2c_device_remove() is executed. This is
573 * needed as some drivers would allocate additional resources,
574 * for example when updating firmware.
578 goto err_release_driver_resources;
582 err_release_driver_resources:
583 devres_release_group(&client->dev, client->devres_group_id);
584 err_detach_pm_domain:
585 dev_pm_domain_detach(&client->dev, do_power_on);
586 err_clear_wakeup_irq:
587 dev_pm_clear_wake_irq(&client->dev);
588 device_init_wakeup(&client->dev, false);
590 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
591 pm_runtime_put_sync(&client->adapter->dev);
596 static void i2c_device_remove(struct device *dev)
598 struct i2c_client *client = to_i2c_client(dev);
599 struct i2c_driver *driver;
601 driver = to_i2c_driver(dev->driver);
602 if (driver->remove) {
603 dev_dbg(dev, "remove\n");
605 driver->remove(client);
608 devres_release_group(&client->dev, client->devres_group_id);
610 dev_pm_domain_detach(&client->dev, true);
612 dev_pm_clear_wake_irq(&client->dev);
613 device_init_wakeup(&client->dev, false);
616 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
617 pm_runtime_put(&client->adapter->dev);
620 static void i2c_device_shutdown(struct device *dev)
622 struct i2c_client *client = i2c_verify_client(dev);
623 struct i2c_driver *driver;
625 if (!client || !dev->driver)
627 driver = to_i2c_driver(dev->driver);
628 if (driver->shutdown)
629 driver->shutdown(client);
630 else if (client->irq > 0)
631 disable_irq(client->irq);
634 static void i2c_client_dev_release(struct device *dev)
636 kfree(to_i2c_client(dev));
640 name_show(struct device *dev, struct device_attribute *attr, char *buf)
642 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
643 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
645 static DEVICE_ATTR_RO(name);
648 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
650 struct i2c_client *client = to_i2c_client(dev);
653 len = of_device_modalias(dev, buf, PAGE_SIZE);
657 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
661 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
663 static DEVICE_ATTR_RO(modalias);
665 static struct attribute *i2c_dev_attrs[] = {
667 /* modalias helps coldplug: modprobe $(cat .../modalias) */
668 &dev_attr_modalias.attr,
671 ATTRIBUTE_GROUPS(i2c_dev);
673 struct bus_type i2c_bus_type = {
675 .match = i2c_device_match,
676 .probe = i2c_device_probe,
677 .remove = i2c_device_remove,
678 .shutdown = i2c_device_shutdown,
680 EXPORT_SYMBOL_GPL(i2c_bus_type);
682 struct device_type i2c_client_type = {
683 .groups = i2c_dev_groups,
684 .uevent = i2c_device_uevent,
685 .release = i2c_client_dev_release,
687 EXPORT_SYMBOL_GPL(i2c_client_type);
691 * i2c_verify_client - return parameter as i2c_client, or NULL
692 * @dev: device, probably from some driver model iterator
694 * When traversing the driver model tree, perhaps using driver model
695 * iterators like @device_for_each_child(), you can't assume very much
696 * about the nodes you find. Use this function to avoid oopses caused
697 * by wrongly treating some non-I2C device as an i2c_client.
699 struct i2c_client *i2c_verify_client(struct device *dev)
701 return (dev->type == &i2c_client_type)
705 EXPORT_SYMBOL(i2c_verify_client);
708 /* Return a unique address which takes the flags of the client into account */
709 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
711 unsigned short addr = client->addr;
713 /* For some client flags, add an arbitrary offset to avoid collisions */
714 if (client->flags & I2C_CLIENT_TEN)
715 addr |= I2C_ADDR_OFFSET_TEN_BIT;
717 if (client->flags & I2C_CLIENT_SLAVE)
718 addr |= I2C_ADDR_OFFSET_SLAVE;
723 /* This is a permissive address validity check, I2C address map constraints
724 * are purposely not enforced, except for the general call address. */
725 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
727 if (flags & I2C_CLIENT_TEN) {
728 /* 10-bit address, all values are valid */
732 /* 7-bit address, reject the general call address */
733 if (addr == 0x00 || addr > 0x7f)
739 /* And this is a strict address validity check, used when probing. If a
740 * device uses a reserved address, then it shouldn't be probed. 7-bit
741 * addressing is assumed, 10-bit address devices are rare and should be
742 * explicitly enumerated. */
743 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
746 * Reserved addresses per I2C specification:
747 * 0x00 General call address / START byte
749 * 0x02 Reserved for different bus format
750 * 0x03 Reserved for future purposes
751 * 0x04-0x07 Hs-mode master code
752 * 0x78-0x7b 10-bit slave addressing
753 * 0x7c-0x7f Reserved for future purposes
755 if (addr < 0x08 || addr > 0x77)
760 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
762 struct i2c_client *client = i2c_verify_client(dev);
763 int addr = *(int *)addrp;
765 if (client && i2c_encode_flags_to_addr(client) == addr)
770 /* walk up mux tree */
771 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
773 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
776 result = device_for_each_child(&adapter->dev, &addr,
777 __i2c_check_addr_busy);
779 if (!result && parent)
780 result = i2c_check_mux_parents(parent, addr);
785 /* recurse down mux tree */
786 static int i2c_check_mux_children(struct device *dev, void *addrp)
790 if (dev->type == &i2c_adapter_type)
791 result = device_for_each_child(dev, addrp,
792 i2c_check_mux_children);
794 result = __i2c_check_addr_busy(dev, addrp);
799 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
801 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
805 result = i2c_check_mux_parents(parent, addr);
808 result = device_for_each_child(&adapter->dev, &addr,
809 i2c_check_mux_children);
815 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
816 * @adapter: Target I2C bus segment
817 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
818 * locks only this branch in the adapter tree
820 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
823 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
827 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
828 * @adapter: Target I2C bus segment
829 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
830 * trylocks only this branch in the adapter tree
832 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
835 return rt_mutex_trylock(&adapter->bus_lock);
839 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
840 * @adapter: Target I2C bus segment
841 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
842 * unlocks only this branch in the adapter tree
844 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
847 rt_mutex_unlock(&adapter->bus_lock);
850 static void i2c_dev_set_name(struct i2c_adapter *adap,
851 struct i2c_client *client,
852 struct i2c_board_info const *info)
854 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
856 if (info && info->dev_name) {
857 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
862 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
866 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
867 i2c_encode_flags_to_addr(client));
870 int i2c_dev_irq_from_resources(const struct resource *resources,
871 unsigned int num_resources)
873 struct irq_data *irqd;
876 for (i = 0; i < num_resources; i++) {
877 const struct resource *r = &resources[i];
879 if (resource_type(r) != IORESOURCE_IRQ)
882 if (r->flags & IORESOURCE_BITS) {
883 irqd = irq_get_irq_data(r->start);
887 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
897 * i2c_new_client_device - instantiate an i2c device
898 * @adap: the adapter managing the device
899 * @info: describes one I2C device; bus_num is ignored
902 * Create an i2c device. Binding is handled through driver model
903 * probe()/remove() methods. A driver may be bound to this device when we
904 * return from this function, or any later moment (e.g. maybe hotplugging will
905 * load the driver module). This call is not appropriate for use by mainboard
906 * initialization logic, which usually runs during an arch_initcall() long
907 * before any i2c_adapter could exist.
909 * This returns the new i2c client, which may be saved for later use with
910 * i2c_unregister_device(); or an ERR_PTR to describe the error.
913 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
915 struct i2c_client *client;
918 client = kzalloc(sizeof *client, GFP_KERNEL);
920 return ERR_PTR(-ENOMEM);
922 client->adapter = adap;
924 client->dev.platform_data = info->platform_data;
925 client->flags = info->flags;
926 client->addr = info->addr;
928 client->init_irq = info->irq;
929 if (!client->init_irq)
930 client->init_irq = i2c_dev_irq_from_resources(info->resources,
931 info->num_resources);
933 strscpy(client->name, info->type, sizeof(client->name));
935 status = i2c_check_addr_validity(client->addr, client->flags);
937 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
938 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
942 /* Check for address business */
943 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
947 client->dev.parent = &client->adapter->dev;
948 client->dev.bus = &i2c_bus_type;
949 client->dev.type = &i2c_client_type;
950 client->dev.of_node = of_node_get(info->of_node);
951 client->dev.fwnode = info->fwnode;
953 device_enable_async_suspend(&client->dev);
954 i2c_dev_set_name(adap, client, info);
957 status = device_add_software_node(&client->dev, info->swnode);
960 "Failed to add software node to client %s: %d\n",
961 client->name, status);
962 goto out_err_put_of_node;
966 status = device_register(&client->dev);
968 goto out_remove_swnode;
970 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
971 client->name, dev_name(&client->dev));
976 device_remove_software_node(&client->dev);
978 of_node_put(info->of_node);
981 "Failed to register i2c client %s at 0x%02x (%d)\n",
982 client->name, client->addr, status);
985 return ERR_PTR(status);
987 EXPORT_SYMBOL_GPL(i2c_new_client_device);
990 * i2c_unregister_device - reverse effect of i2c_new_*_device()
991 * @client: value returned from i2c_new_*_device()
994 void i2c_unregister_device(struct i2c_client *client)
996 if (IS_ERR_OR_NULL(client))
999 if (client->dev.of_node) {
1000 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1001 of_node_put(client->dev.of_node);
1004 if (ACPI_COMPANION(&client->dev))
1005 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1006 device_remove_software_node(&client->dev);
1007 device_unregister(&client->dev);
1009 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1012 * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1013 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1015 * Look up and return the &struct i2c_client corresponding to the @fwnode.
1016 * If no client can be found, or @fwnode is NULL, this returns NULL.
1018 * The user must call put_device(&client->dev) once done with the i2c client.
1020 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1022 struct i2c_client *client;
1028 dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1032 client = i2c_verify_client(dev);
1038 EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1041 static const struct i2c_device_id dummy_id[] = {
1046 static int dummy_probe(struct i2c_client *client)
1051 static struct i2c_driver dummy_driver = {
1052 .driver.name = "dummy",
1053 .probe = dummy_probe,
1054 .id_table = dummy_id,
1058 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1059 * @adapter: the adapter managing the device
1060 * @address: seven bit address to be used
1061 * Context: can sleep
1063 * This returns an I2C client bound to the "dummy" driver, intended for use
1064 * with devices that consume multiple addresses. Examples of such chips
1065 * include various EEPROMS (like 24c04 and 24c08 models).
1067 * These dummy devices have two main uses. First, most I2C and SMBus calls
1068 * except i2c_transfer() need a client handle; the dummy will be that handle.
1069 * And second, this prevents the specified address from being bound to a
1072 * This returns the new i2c client, which should be saved for later use with
1073 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1075 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1077 struct i2c_board_info info = {
1078 I2C_BOARD_INFO("dummy", address),
1081 return i2c_new_client_device(adapter, &info);
1083 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1085 static void devm_i2c_release_dummy(void *client)
1087 i2c_unregister_device(client);
1091 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1092 * @dev: device the managed resource is bound to
1093 * @adapter: the adapter managing the device
1094 * @address: seven bit address to be used
1095 * Context: can sleep
1097 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1098 * new i2c client or an ERR_PTR in case of an error.
1100 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1101 struct i2c_adapter *adapter,
1104 struct i2c_client *client;
1107 client = i2c_new_dummy_device(adapter, address);
1111 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1113 return ERR_PTR(ret);
1117 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1120 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1121 * and create the associated device
1122 * @client: Handle to the primary client
1123 * @name: Handle to specify which secondary address to get
1124 * @default_addr: Used as a fallback if no secondary address was specified
1125 * Context: can sleep
1127 * I2C clients can be composed of multiple I2C slaves bound together in a single
1128 * component. The I2C client driver then binds to the master I2C slave and needs
1129 * to create I2C dummy clients to communicate with all the other slaves.
1131 * This function creates and returns an I2C dummy client whose I2C address is
1132 * retrieved from the platform firmware based on the given slave name. If no
1133 * address is specified by the firmware default_addr is used.
1135 * On DT-based platforms the address is retrieved from the "reg" property entry
1136 * cell whose "reg-names" value matches the slave name.
1138 * This returns the new i2c client, which should be saved for later use with
1139 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1141 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1145 struct device_node *np = client->dev.of_node;
1146 u32 addr = default_addr;
1150 i = of_property_match_string(np, "reg-names", name);
1152 of_property_read_u32_index(np, "reg", i, &addr);
1155 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1156 return i2c_new_dummy_device(client->adapter, addr);
1158 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1160 /* ------------------------------------------------------------------------- */
1162 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1164 static void i2c_adapter_dev_release(struct device *dev)
1166 struct i2c_adapter *adap = to_i2c_adapter(dev);
1167 complete(&adap->dev_released);
1170 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1172 unsigned int depth = 0;
1174 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1177 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1178 "adapter depth exceeds lockdep subclass limit\n");
1182 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1185 * Let users instantiate I2C devices through sysfs. This can be used when
1186 * platform initialization code doesn't contain the proper data for
1187 * whatever reason. Also useful for drivers that do device detection and
1188 * detection fails, either because the device uses an unexpected address,
1189 * or this is a compatible device with different ID register values.
1191 * Parameter checking may look overzealous, but we really don't want
1192 * the user to provide incorrect parameters.
1195 new_device_store(struct device *dev, struct device_attribute *attr,
1196 const char *buf, size_t count)
1198 struct i2c_adapter *adap = to_i2c_adapter(dev);
1199 struct i2c_board_info info;
1200 struct i2c_client *client;
1204 memset(&info, 0, sizeof(struct i2c_board_info));
1206 blank = strchr(buf, ' ');
1208 dev_err(dev, "%s: Missing parameters\n", "new_device");
1211 if (blank - buf > I2C_NAME_SIZE - 1) {
1212 dev_err(dev, "%s: Invalid device name\n", "new_device");
1215 memcpy(info.type, buf, blank - buf);
1217 /* Parse remaining parameters, reject extra parameters */
1218 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1220 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1223 if (res > 1 && end != '\n') {
1224 dev_err(dev, "%s: Extra parameters\n", "new_device");
1228 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1229 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1230 info.flags |= I2C_CLIENT_TEN;
1233 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1234 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1235 info.flags |= I2C_CLIENT_SLAVE;
1238 client = i2c_new_client_device(adap, &info);
1240 return PTR_ERR(client);
1242 /* Keep track of the added device */
1243 mutex_lock(&adap->userspace_clients_lock);
1244 list_add_tail(&client->detected, &adap->userspace_clients);
1245 mutex_unlock(&adap->userspace_clients_lock);
1246 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1247 info.type, info.addr);
1251 static DEVICE_ATTR_WO(new_device);
1254 * And of course let the users delete the devices they instantiated, if
1255 * they got it wrong. This interface can only be used to delete devices
1256 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1257 * don't delete devices to which some kernel code still has references.
1259 * Parameter checking may look overzealous, but we really don't want
1260 * the user to delete the wrong device.
1263 delete_device_store(struct device *dev, struct device_attribute *attr,
1264 const char *buf, size_t count)
1266 struct i2c_adapter *adap = to_i2c_adapter(dev);
1267 struct i2c_client *client, *next;
1268 unsigned short addr;
1272 /* Parse parameters, reject extra parameters */
1273 res = sscanf(buf, "%hi%c", &addr, &end);
1275 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1278 if (res > 1 && end != '\n') {
1279 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1283 /* Make sure the device was added through sysfs */
1285 mutex_lock_nested(&adap->userspace_clients_lock,
1286 i2c_adapter_depth(adap));
1287 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1289 if (i2c_encode_flags_to_addr(client) == addr) {
1290 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1291 "delete_device", client->name, client->addr);
1293 list_del(&client->detected);
1294 i2c_unregister_device(client);
1299 mutex_unlock(&adap->userspace_clients_lock);
1302 dev_err(dev, "%s: Can't find device in list\n",
1306 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1307 delete_device_store);
1309 static struct attribute *i2c_adapter_attrs[] = {
1310 &dev_attr_name.attr,
1311 &dev_attr_new_device.attr,
1312 &dev_attr_delete_device.attr,
1315 ATTRIBUTE_GROUPS(i2c_adapter);
1317 struct device_type i2c_adapter_type = {
1318 .groups = i2c_adapter_groups,
1319 .release = i2c_adapter_dev_release,
1321 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1324 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1325 * @dev: device, probably from some driver model iterator
1327 * When traversing the driver model tree, perhaps using driver model
1328 * iterators like @device_for_each_child(), you can't assume very much
1329 * about the nodes you find. Use this function to avoid oopses caused
1330 * by wrongly treating some non-I2C device as an i2c_adapter.
1332 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1334 return (dev->type == &i2c_adapter_type)
1335 ? to_i2c_adapter(dev)
1338 EXPORT_SYMBOL(i2c_verify_adapter);
1340 #ifdef CONFIG_I2C_COMPAT
1341 static struct class_compat *i2c_adapter_compat_class;
1344 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1346 struct i2c_devinfo *devinfo;
1348 down_read(&__i2c_board_lock);
1349 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1350 if (devinfo->busnum == adapter->nr &&
1351 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1352 dev_err(&adapter->dev,
1353 "Can't create device at 0x%02x\n",
1354 devinfo->board_info.addr);
1356 up_read(&__i2c_board_lock);
1359 static int i2c_do_add_adapter(struct i2c_driver *driver,
1360 struct i2c_adapter *adap)
1362 /* Detect supported devices on that bus, and instantiate them */
1363 i2c_detect(adap, driver);
1368 static int __process_new_adapter(struct device_driver *d, void *data)
1370 return i2c_do_add_adapter(to_i2c_driver(d), data);
1373 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1374 .lock_bus = i2c_adapter_lock_bus,
1375 .trylock_bus = i2c_adapter_trylock_bus,
1376 .unlock_bus = i2c_adapter_unlock_bus,
1379 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1381 struct irq_domain *domain = adap->host_notify_domain;
1382 irq_hw_number_t hwirq;
1387 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1388 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1390 irq_domain_remove(domain);
1391 adap->host_notify_domain = NULL;
1394 static int i2c_host_notify_irq_map(struct irq_domain *h,
1396 irq_hw_number_t hw_irq_num)
1398 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1403 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1404 .map = i2c_host_notify_irq_map,
1407 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1409 struct irq_domain *domain;
1411 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1414 domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1415 I2C_ADDR_7BITS_COUNT,
1416 &i2c_host_notify_irq_ops, adap);
1420 adap->host_notify_domain = domain;
1426 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1428 * @adap: the adapter
1429 * @addr: the I2C address of the notifying device
1430 * Context: can't sleep
1432 * Helper function to be called from an I2C bus driver's interrupt
1433 * handler. It will schedule the Host Notify IRQ.
1435 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1442 irq = irq_find_mapping(adap->host_notify_domain, addr);
1446 generic_handle_irq_safe(irq);
1450 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1452 static int i2c_register_adapter(struct i2c_adapter *adap)
1456 /* Can't register until after driver model init */
1457 if (WARN_ON(!is_registered)) {
1463 if (WARN(!adap->name[0], "i2c adapter has no name"))
1467 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1471 if (!adap->lock_ops)
1472 adap->lock_ops = &i2c_adapter_lock_ops;
1474 adap->locked_flags = 0;
1475 rt_mutex_init(&adap->bus_lock);
1476 rt_mutex_init(&adap->mux_lock);
1477 mutex_init(&adap->userspace_clients_lock);
1478 INIT_LIST_HEAD(&adap->userspace_clients);
1480 /* Set default timeout to 1 second if not already set */
1481 if (adap->timeout == 0)
1484 /* register soft irqs for Host Notify */
1485 res = i2c_setup_host_notify_irq_domain(adap);
1487 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1492 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1493 adap->dev.bus = &i2c_bus_type;
1494 adap->dev.type = &i2c_adapter_type;
1495 res = device_register(&adap->dev);
1497 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1501 res = i2c_setup_smbus_alert(adap);
1505 device_enable_async_suspend(&adap->dev);
1506 pm_runtime_no_callbacks(&adap->dev);
1507 pm_suspend_ignore_children(&adap->dev, true);
1508 pm_runtime_enable(&adap->dev);
1510 res = i2c_init_recovery(adap);
1511 if (res == -EPROBE_DEFER)
1514 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1516 #ifdef CONFIG_I2C_COMPAT
1517 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1520 dev_warn(&adap->dev,
1521 "Failed to create compatibility class link\n");
1524 /* create pre-declared device nodes */
1525 of_i2c_register_devices(adap);
1526 i2c_acpi_install_space_handler(adap);
1527 i2c_acpi_register_devices(adap);
1529 if (adap->nr < __i2c_first_dynamic_bus_num)
1530 i2c_scan_static_board_info(adap);
1532 /* Notify drivers */
1533 mutex_lock(&core_lock);
1534 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1535 mutex_unlock(&core_lock);
1540 init_completion(&adap->dev_released);
1541 device_unregister(&adap->dev);
1542 wait_for_completion(&adap->dev_released);
1544 mutex_lock(&core_lock);
1545 idr_remove(&i2c_adapter_idr, adap->nr);
1546 mutex_unlock(&core_lock);
1551 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1552 * @adap: the adapter to register (with adap->nr initialized)
1553 * Context: can sleep
1555 * See i2c_add_numbered_adapter() for details.
1557 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1561 mutex_lock(&core_lock);
1562 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1563 mutex_unlock(&core_lock);
1564 if (WARN(id < 0, "couldn't get idr"))
1565 return id == -ENOSPC ? -EBUSY : id;
1567 return i2c_register_adapter(adap);
1571 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1572 * @adapter: the adapter to add
1573 * Context: can sleep
1575 * This routine is used to declare an I2C adapter when its bus number
1576 * doesn't matter or when its bus number is specified by an dt alias.
1577 * Examples of bases when the bus number doesn't matter: I2C adapters
1578 * dynamically added by USB links or PCI plugin cards.
1580 * When this returns zero, a new bus number was allocated and stored
1581 * in adap->nr, and the specified adapter became available for clients.
1582 * Otherwise, a negative errno value is returned.
1584 int i2c_add_adapter(struct i2c_adapter *adapter)
1586 struct device *dev = &adapter->dev;
1590 id = of_alias_get_id(dev->of_node, "i2c");
1593 return __i2c_add_numbered_adapter(adapter);
1597 mutex_lock(&core_lock);
1598 id = idr_alloc(&i2c_adapter_idr, adapter,
1599 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1600 mutex_unlock(&core_lock);
1601 if (WARN(id < 0, "couldn't get idr"))
1606 return i2c_register_adapter(adapter);
1608 EXPORT_SYMBOL(i2c_add_adapter);
1611 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1612 * @adap: the adapter to register (with adap->nr initialized)
1613 * Context: can sleep
1615 * This routine is used to declare an I2C adapter when its bus number
1616 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1617 * or otherwise built in to the system's mainboard, and where i2c_board_info
1618 * is used to properly configure I2C devices.
1620 * If the requested bus number is set to -1, then this function will behave
1621 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1623 * If no devices have pre-been declared for this bus, then be sure to
1624 * register the adapter before any dynamically allocated ones. Otherwise
1625 * the required bus ID may not be available.
1627 * When this returns zero, the specified adapter became available for
1628 * clients using the bus number provided in adap->nr. Also, the table
1629 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1630 * and the appropriate driver model device nodes are created. Otherwise, a
1631 * negative errno value is returned.
1633 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1635 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1636 return i2c_add_adapter(adap);
1638 return __i2c_add_numbered_adapter(adap);
1640 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1642 static void i2c_do_del_adapter(struct i2c_driver *driver,
1643 struct i2c_adapter *adapter)
1645 struct i2c_client *client, *_n;
1647 /* Remove the devices we created ourselves as the result of hardware
1648 * probing (using a driver's detect method) */
1649 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1650 if (client->adapter == adapter) {
1651 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1652 client->name, client->addr);
1653 list_del(&client->detected);
1654 i2c_unregister_device(client);
1659 static int __unregister_client(struct device *dev, void *dummy)
1661 struct i2c_client *client = i2c_verify_client(dev);
1662 if (client && strcmp(client->name, "dummy"))
1663 i2c_unregister_device(client);
1667 static int __unregister_dummy(struct device *dev, void *dummy)
1669 struct i2c_client *client = i2c_verify_client(dev);
1670 i2c_unregister_device(client);
1674 static int __process_removed_adapter(struct device_driver *d, void *data)
1676 i2c_do_del_adapter(to_i2c_driver(d), data);
1681 * i2c_del_adapter - unregister I2C adapter
1682 * @adap: the adapter being unregistered
1683 * Context: can sleep
1685 * This unregisters an I2C adapter which was previously registered
1686 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1688 void i2c_del_adapter(struct i2c_adapter *adap)
1690 struct i2c_adapter *found;
1691 struct i2c_client *client, *next;
1693 /* First make sure that this adapter was ever added */
1694 mutex_lock(&core_lock);
1695 found = idr_find(&i2c_adapter_idr, adap->nr);
1696 mutex_unlock(&core_lock);
1697 if (found != adap) {
1698 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1702 i2c_acpi_remove_space_handler(adap);
1703 /* Tell drivers about this removal */
1704 mutex_lock(&core_lock);
1705 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1706 __process_removed_adapter);
1707 mutex_unlock(&core_lock);
1709 /* Remove devices instantiated from sysfs */
1710 mutex_lock_nested(&adap->userspace_clients_lock,
1711 i2c_adapter_depth(adap));
1712 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1714 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1716 list_del(&client->detected);
1717 i2c_unregister_device(client);
1719 mutex_unlock(&adap->userspace_clients_lock);
1721 /* Detach any active clients. This can't fail, thus we do not
1722 * check the returned value. This is a two-pass process, because
1723 * we can't remove the dummy devices during the first pass: they
1724 * could have been instantiated by real devices wishing to clean
1725 * them up properly, so we give them a chance to do that first. */
1726 device_for_each_child(&adap->dev, NULL, __unregister_client);
1727 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1729 #ifdef CONFIG_I2C_COMPAT
1730 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1734 /* device name is gone after device_unregister */
1735 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1737 pm_runtime_disable(&adap->dev);
1739 i2c_host_notify_irq_teardown(adap);
1741 /* wait until all references to the device are gone
1743 * FIXME: This is old code and should ideally be replaced by an
1744 * alternative which results in decoupling the lifetime of the struct
1745 * device from the i2c_adapter, like spi or netdev do. Any solution
1746 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1748 init_completion(&adap->dev_released);
1749 device_unregister(&adap->dev);
1750 wait_for_completion(&adap->dev_released);
1753 mutex_lock(&core_lock);
1754 idr_remove(&i2c_adapter_idr, adap->nr);
1755 mutex_unlock(&core_lock);
1757 /* Clear the device structure in case this adapter is ever going to be
1759 memset(&adap->dev, 0, sizeof(adap->dev));
1761 EXPORT_SYMBOL(i2c_del_adapter);
1763 static void devm_i2c_del_adapter(void *adapter)
1765 i2c_del_adapter(adapter);
1769 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1770 * @dev: managing device for adding this I2C adapter
1771 * @adapter: the adapter to add
1772 * Context: can sleep
1774 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1775 * but the adapter will be auto deleted on driver detach.
1777 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1781 ret = i2c_add_adapter(adapter);
1785 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1787 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1789 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1791 if (dev_fwnode(dev) == data)
1794 if (dev->parent && dev_fwnode(dev->parent) == data)
1801 * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1802 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1804 * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1805 * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1807 * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1809 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1811 struct i2c_adapter *adapter;
1817 dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1818 i2c_dev_or_parent_fwnode_match);
1822 adapter = i2c_verify_adapter(dev);
1828 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1831 * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1832 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1834 * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1835 * and increment the adapter module's use count. If no adapter can be found,
1836 * or @fwnode is NULL, this returns NULL.
1838 * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1839 * Note that this is different from i2c_find_adapter_by_node().
1841 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1843 struct i2c_adapter *adapter;
1845 adapter = i2c_find_adapter_by_fwnode(fwnode);
1849 if (!try_module_get(adapter->owner)) {
1850 put_device(&adapter->dev);
1856 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1858 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1859 u32 def_val, bool use_def)
1863 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1865 *cur_val_p = def_val;
1867 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1871 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1872 * @dev: The device to scan for I2C timing properties
1873 * @t: the i2c_timings struct to be filled with values
1874 * @use_defaults: bool to use sane defaults derived from the I2C specification
1875 * when properties are not found, otherwise don't update
1877 * Scan the device for the generic I2C properties describing timing parameters
1878 * for the signal and fill the given struct with the results. If a property was
1879 * not found and use_defaults was true, then maximum timings are assumed which
1880 * are derived from the I2C specification. If use_defaults is not used, the
1881 * results will be as before, so drivers can apply their own defaults before
1882 * calling this helper. The latter is mainly intended for avoiding regressions
1883 * of existing drivers which want to switch to this function. New drivers
1884 * almost always should use the defaults.
1886 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1888 bool u = use_defaults;
1891 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1892 I2C_MAX_STANDARD_MODE_FREQ, u);
1894 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1895 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1896 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1898 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1899 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1901 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1902 &t->scl_int_delay_ns, 0, u);
1903 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1905 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1906 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1907 &t->digital_filter_width_ns, 0, u);
1908 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1909 &t->analog_filter_cutoff_freq_hz, 0, u);
1911 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1913 /* ------------------------------------------------------------------------- */
1915 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1919 mutex_lock(&core_lock);
1920 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1921 mutex_unlock(&core_lock);
1925 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1927 static int __process_new_driver(struct device *dev, void *data)
1929 if (dev->type != &i2c_adapter_type)
1931 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1935 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1936 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1939 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1943 /* Can't register until after driver model init */
1944 if (WARN_ON(!is_registered))
1947 /* add the driver to the list of i2c drivers in the driver core */
1948 driver->driver.owner = owner;
1949 driver->driver.bus = &i2c_bus_type;
1950 INIT_LIST_HEAD(&driver->clients);
1952 /* When registration returns, the driver core
1953 * will have called probe() for all matching-but-unbound devices.
1955 res = driver_register(&driver->driver);
1959 pr_debug("driver [%s] registered\n", driver->driver.name);
1961 /* Walk the adapters that are already present */
1962 i2c_for_each_dev(driver, __process_new_driver);
1966 EXPORT_SYMBOL(i2c_register_driver);
1968 static int __process_removed_driver(struct device *dev, void *data)
1970 if (dev->type == &i2c_adapter_type)
1971 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1976 * i2c_del_driver - unregister I2C driver
1977 * @driver: the driver being unregistered
1978 * Context: can sleep
1980 void i2c_del_driver(struct i2c_driver *driver)
1982 i2c_for_each_dev(driver, __process_removed_driver);
1984 driver_unregister(&driver->driver);
1985 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1987 EXPORT_SYMBOL(i2c_del_driver);
1989 /* ------------------------------------------------------------------------- */
1991 struct i2c_cmd_arg {
1996 static int i2c_cmd(struct device *dev, void *_arg)
1998 struct i2c_client *client = i2c_verify_client(dev);
1999 struct i2c_cmd_arg *arg = _arg;
2000 struct i2c_driver *driver;
2002 if (!client || !client->dev.driver)
2005 driver = to_i2c_driver(client->dev.driver);
2006 if (driver->command)
2007 driver->command(client, arg->cmd, arg->arg);
2011 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2013 struct i2c_cmd_arg cmd_arg;
2017 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2019 EXPORT_SYMBOL(i2c_clients_command);
2021 static int __init i2c_init(void)
2025 retval = of_alias_get_highest_id("i2c");
2027 down_write(&__i2c_board_lock);
2028 if (retval >= __i2c_first_dynamic_bus_num)
2029 __i2c_first_dynamic_bus_num = retval + 1;
2030 up_write(&__i2c_board_lock);
2032 retval = bus_register(&i2c_bus_type);
2036 is_registered = true;
2038 #ifdef CONFIG_I2C_COMPAT
2039 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2040 if (!i2c_adapter_compat_class) {
2045 retval = i2c_add_driver(&dummy_driver);
2049 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2050 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2051 if (IS_ENABLED(CONFIG_ACPI))
2052 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2057 #ifdef CONFIG_I2C_COMPAT
2058 class_compat_unregister(i2c_adapter_compat_class);
2061 is_registered = false;
2062 bus_unregister(&i2c_bus_type);
2066 static void __exit i2c_exit(void)
2068 if (IS_ENABLED(CONFIG_ACPI))
2069 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2070 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2071 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2072 i2c_del_driver(&dummy_driver);
2073 #ifdef CONFIG_I2C_COMPAT
2074 class_compat_unregister(i2c_adapter_compat_class);
2076 bus_unregister(&i2c_bus_type);
2077 tracepoint_synchronize_unregister();
2080 /* We must initialize early, because some subsystems register i2c drivers
2081 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2083 postcore_initcall(i2c_init);
2084 module_exit(i2c_exit);
2086 /* ----------------------------------------------------
2087 * the functional interface to the i2c busses.
2088 * ----------------------------------------------------
2091 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2092 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2094 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2096 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2097 err_msg, msg->addr, msg->len,
2098 msg->flags & I2C_M_RD ? "read" : "write");
2102 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2104 const struct i2c_adapter_quirks *q = adap->quirks;
2105 int max_num = q->max_num_msgs, i;
2106 bool do_len_check = true;
2108 if (q->flags & I2C_AQ_COMB) {
2111 /* special checks for combined messages */
2113 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2114 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2116 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2117 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2119 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2120 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2122 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2123 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2125 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2126 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2128 do_len_check = false;
2132 if (i2c_quirk_exceeded(num, max_num))
2133 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2135 for (i = 0; i < num; i++) {
2136 u16 len = msgs[i].len;
2138 if (msgs[i].flags & I2C_M_RD) {
2139 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2140 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2142 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2143 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2145 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2146 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2148 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2149 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2157 * __i2c_transfer - unlocked flavor of i2c_transfer
2158 * @adap: Handle to I2C bus
2159 * @msgs: One or more messages to execute before STOP is issued to
2160 * terminate the operation; each message begins with a START.
2161 * @num: Number of messages to be executed.
2163 * Returns negative errno, else the number of messages executed.
2165 * Adapter lock must be held when calling this function. No debug logging
2166 * takes place. adap->algo->master_xfer existence isn't checked.
2168 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2170 unsigned long orig_jiffies;
2173 if (WARN_ON(!msgs || num < 1))
2176 ret = __i2c_check_suspended(adap);
2180 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2184 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2185 * enabled. This is an efficient way of keeping the for-loop from
2186 * being executed when not needed.
2188 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2190 for (i = 0; i < num; i++)
2191 if (msgs[i].flags & I2C_M_RD)
2192 trace_i2c_read(adap, &msgs[i], i);
2194 trace_i2c_write(adap, &msgs[i], i);
2197 /* Retry automatically on arbitration loss */
2198 orig_jiffies = jiffies;
2199 for (ret = 0, try = 0; try <= adap->retries; try++) {
2200 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2201 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2203 ret = adap->algo->master_xfer(adap, msgs, num);
2207 if (time_after(jiffies, orig_jiffies + adap->timeout))
2211 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2213 for (i = 0; i < ret; i++)
2214 if (msgs[i].flags & I2C_M_RD)
2215 trace_i2c_reply(adap, &msgs[i], i);
2216 trace_i2c_result(adap, num, ret);
2221 EXPORT_SYMBOL(__i2c_transfer);
2224 * i2c_transfer - execute a single or combined I2C message
2225 * @adap: Handle to I2C bus
2226 * @msgs: One or more messages to execute before STOP is issued to
2227 * terminate the operation; each message begins with a START.
2228 * @num: Number of messages to be executed.
2230 * Returns negative errno, else the number of messages executed.
2232 * Note that there is no requirement that each message be sent to
2233 * the same slave address, although that is the most common model.
2235 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2239 if (!adap->algo->master_xfer) {
2240 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2244 /* REVISIT the fault reporting model here is weak:
2246 * - When we get an error after receiving N bytes from a slave,
2247 * there is no way to report "N".
2249 * - When we get a NAK after transmitting N bytes to a slave,
2250 * there is no way to report "N" ... or to let the master
2251 * continue executing the rest of this combined message, if
2252 * that's the appropriate response.
2254 * - When for example "num" is two and we successfully complete
2255 * the first message but get an error part way through the
2256 * second, it's unclear whether that should be reported as
2257 * one (discarding status on the second message) or errno
2258 * (discarding status on the first one).
2260 ret = __i2c_lock_bus_helper(adap);
2264 ret = __i2c_transfer(adap, msgs, num);
2265 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2269 EXPORT_SYMBOL(i2c_transfer);
2272 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2274 * @client: Handle to slave device
2275 * @buf: Where the data is stored
2276 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2277 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2279 * Returns negative errno, or else the number of bytes transferred.
2281 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2282 int count, u16 flags)
2285 struct i2c_msg msg = {
2286 .addr = client->addr,
2287 .flags = flags | (client->flags & I2C_M_TEN),
2292 ret = i2c_transfer(client->adapter, &msg, 1);
2295 * If everything went ok (i.e. 1 msg transferred), return #bytes
2296 * transferred, else error code.
2298 return (ret == 1) ? count : ret;
2300 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2303 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2304 * @client: The device to query
2305 * @id: The queried information
2307 * Returns negative errno on error, zero on success.
2309 int i2c_get_device_id(const struct i2c_client *client,
2310 struct i2c_device_identity *id)
2312 struct i2c_adapter *adap = client->adapter;
2313 union i2c_smbus_data raw_id;
2316 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2319 raw_id.block[0] = 3;
2320 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2321 I2C_SMBUS_READ, client->addr << 1,
2322 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2326 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2327 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2328 id->die_revision = raw_id.block[3] & 0x7;
2331 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2334 * i2c_client_get_device_id - get the driver match table entry of a device
2335 * @client: the device to query. The device must be bound to a driver
2337 * Returns a pointer to the matching entry if found, NULL otherwise.
2339 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2341 const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2343 return i2c_match_id(drv->id_table, client);
2345 EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2347 /* ----------------------------------------------------
2348 * the i2c address scanning function
2349 * Will not work for 10-bit addresses!
2350 * ----------------------------------------------------
2354 * Legacy default probe function, mostly relevant for SMBus. The default
2355 * probe method is a quick write, but it is known to corrupt the 24RF08
2356 * EEPROMs due to a state machine bug, and could also irreversibly
2357 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2358 * we use a short byte read instead. Also, some bus drivers don't implement
2359 * quick write, so we fallback to a byte read in that case too.
2360 * On x86, there is another special case for FSC hardware monitoring chips,
2361 * which want regular byte reads (address 0x73.) Fortunately, these are the
2362 * only known chips using this I2C address on PC hardware.
2363 * Returns 1 if probe succeeded, 0 if not.
2365 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2368 union i2c_smbus_data dummy;
2371 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2372 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2373 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2374 I2C_SMBUS_BYTE_DATA, &dummy);
2377 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2378 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2379 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2380 I2C_SMBUS_QUICK, NULL);
2381 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2382 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2383 I2C_SMBUS_BYTE, &dummy);
2385 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2393 static int i2c_detect_address(struct i2c_client *temp_client,
2394 struct i2c_driver *driver)
2396 struct i2c_board_info info;
2397 struct i2c_adapter *adapter = temp_client->adapter;
2398 int addr = temp_client->addr;
2401 /* Make sure the address is valid */
2402 err = i2c_check_7bit_addr_validity_strict(addr);
2404 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2409 /* Skip if already in use (7 bit, no need to encode flags) */
2410 if (i2c_check_addr_busy(adapter, addr))
2413 /* Make sure there is something at this address */
2414 if (!i2c_default_probe(adapter, addr))
2417 /* Finally call the custom detection function */
2418 memset(&info, 0, sizeof(struct i2c_board_info));
2420 err = driver->detect(temp_client, &info);
2422 /* -ENODEV is returned if the detection fails. We catch it
2423 here as this isn't an error. */
2424 return err == -ENODEV ? 0 : err;
2427 /* Consistency check */
2428 if (info.type[0] == '\0') {
2429 dev_err(&adapter->dev,
2430 "%s detection function provided no name for 0x%x\n",
2431 driver->driver.name, addr);
2433 struct i2c_client *client;
2435 /* Detection succeeded, instantiate the device */
2436 if (adapter->class & I2C_CLASS_DEPRECATED)
2437 dev_warn(&adapter->dev,
2438 "This adapter will soon drop class based instantiation of devices. "
2439 "Please make sure client 0x%02x gets instantiated by other means. "
2440 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2443 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2444 info.type, info.addr);
2445 client = i2c_new_client_device(adapter, &info);
2446 if (!IS_ERR(client))
2447 list_add_tail(&client->detected, &driver->clients);
2449 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2450 info.type, info.addr);
2455 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2457 const unsigned short *address_list;
2458 struct i2c_client *temp_client;
2461 address_list = driver->address_list;
2462 if (!driver->detect || !address_list)
2465 /* Warn that the adapter lost class based instantiation */
2466 if (adapter->class == I2C_CLASS_DEPRECATED) {
2467 dev_dbg(&adapter->dev,
2468 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2469 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2470 driver->driver.name);
2474 /* Stop here if the classes do not match */
2475 if (!(adapter->class & driver->class))
2478 /* Set up a temporary client to help detect callback */
2479 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2482 temp_client->adapter = adapter;
2484 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2485 dev_dbg(&adapter->dev,
2486 "found normal entry for adapter %d, addr 0x%02x\n",
2487 i2c_adapter_id(adapter), address_list[i]);
2488 temp_client->addr = address_list[i];
2489 err = i2c_detect_address(temp_client, driver);
2498 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2500 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2501 I2C_SMBUS_QUICK, NULL) >= 0;
2503 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2506 i2c_new_scanned_device(struct i2c_adapter *adap,
2507 struct i2c_board_info *info,
2508 unsigned short const *addr_list,
2509 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2514 probe = i2c_default_probe;
2516 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2517 /* Check address validity */
2518 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2519 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2524 /* Check address availability (7 bit, no need to encode flags) */
2525 if (i2c_check_addr_busy(adap, addr_list[i])) {
2527 "Address 0x%02x already in use, not probing\n",
2532 /* Test address responsiveness */
2533 if (probe(adap, addr_list[i]))
2537 if (addr_list[i] == I2C_CLIENT_END) {
2538 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2539 return ERR_PTR(-ENODEV);
2542 info->addr = addr_list[i];
2543 return i2c_new_client_device(adap, info);
2545 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2547 struct i2c_adapter *i2c_get_adapter(int nr)
2549 struct i2c_adapter *adapter;
2551 mutex_lock(&core_lock);
2552 adapter = idr_find(&i2c_adapter_idr, nr);
2556 if (try_module_get(adapter->owner))
2557 get_device(&adapter->dev);
2562 mutex_unlock(&core_lock);
2565 EXPORT_SYMBOL(i2c_get_adapter);
2567 void i2c_put_adapter(struct i2c_adapter *adap)
2572 module_put(adap->owner);
2573 /* Should be last, otherwise we risk use-after-free with 'adap' */
2574 put_device(&adap->dev);
2576 EXPORT_SYMBOL(i2c_put_adapter);
2579 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2580 * @msg: the message to be checked
2581 * @threshold: the minimum number of bytes for which using DMA makes sense.
2582 * Should at least be 1.
2584 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2585 * Or a valid pointer to be used with DMA. After use, release it by
2586 * calling i2c_put_dma_safe_msg_buf().
2588 * This function must only be called from process context!
2590 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2592 /* also skip 0-length msgs for bogus thresholds of 0 */
2594 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2596 if (msg->len < threshold || msg->len == 0)
2599 if (msg->flags & I2C_M_DMA_SAFE)
2602 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2603 msg->addr, msg->len);
2605 if (msg->flags & I2C_M_RD)
2606 return kzalloc(msg->len, GFP_KERNEL);
2608 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2610 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2613 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2614 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2615 * @msg: the message which the buffer corresponds to
2616 * @xferred: bool saying if the message was transferred
2618 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2620 if (!buf || buf == msg->buf)
2623 if (xferred && msg->flags & I2C_M_RD)
2624 memcpy(msg->buf, buf, msg->len);
2628 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2630 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2631 MODULE_DESCRIPTION("I2C-Bus main module");
2632 MODULE_LICENSE("GPL");