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/irqflags.h>
28 #include <linux/jump_label.h>
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/mutex.h>
32 #include <linux/of_device.h>
34 #include <linux/of_irq.h>
35 #include <linux/pinctrl/consumer.h>
36 #include <linux/pm_domain.h>
37 #include <linux/pm_runtime.h>
38 #include <linux/pm_wakeirq.h>
39 #include <linux/property.h>
40 #include <linux/rwsem.h>
41 #include <linux/slab.h>
45 #define CREATE_TRACE_POINTS
46 #include <trace/events/i2c.h>
48 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
49 #define I2C_ADDR_OFFSET_SLAVE 0x1000
51 #define I2C_ADDR_7BITS_MAX 0x77
52 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
54 #define I2C_ADDR_DEVICE_ID 0x7c
57 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
58 * deletion of detected devices are serialized
60 static DEFINE_MUTEX(core_lock);
61 static DEFINE_IDR(i2c_adapter_idr);
63 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
65 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
66 static bool is_registered;
68 int i2c_transfer_trace_reg(void)
70 static_branch_inc(&i2c_trace_msg_key);
74 void i2c_transfer_trace_unreg(void)
76 static_branch_dec(&i2c_trace_msg_key);
79 const char *i2c_freq_mode_string(u32 bus_freq_hz)
81 switch (bus_freq_hz) {
82 case I2C_MAX_STANDARD_MODE_FREQ:
83 return "Standard Mode (100 kHz)";
84 case I2C_MAX_FAST_MODE_FREQ:
85 return "Fast Mode (400 kHz)";
86 case I2C_MAX_FAST_MODE_PLUS_FREQ:
87 return "Fast Mode Plus (1.0 MHz)";
88 case I2C_MAX_TURBO_MODE_FREQ:
89 return "Turbo Mode (1.4 MHz)";
90 case I2C_MAX_HIGH_SPEED_MODE_FREQ:
91 return "High Speed Mode (3.4 MHz)";
92 case I2C_MAX_ULTRA_FAST_MODE_FREQ:
93 return "Ultra Fast Mode (5.0 MHz)";
95 return "Unknown Mode";
98 EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
100 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
101 const struct i2c_client *client)
106 while (id->name[0]) {
107 if (strcmp(client->name, id->name) == 0)
113 EXPORT_SYMBOL_GPL(i2c_match_id);
115 static int i2c_device_match(struct device *dev, struct device_driver *drv)
117 struct i2c_client *client = i2c_verify_client(dev);
118 struct i2c_driver *driver;
121 /* Attempt an OF style match */
122 if (i2c_of_match_device(drv->of_match_table, client))
125 /* Then ACPI style match */
126 if (acpi_driver_match_device(dev, drv))
129 driver = to_i2c_driver(drv);
131 /* Finally an I2C match */
132 if (i2c_match_id(driver->id_table, client))
138 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
140 struct i2c_client *client = to_i2c_client(dev);
143 rc = of_device_uevent_modalias(dev, env);
147 rc = acpi_device_uevent_modalias(dev, env);
151 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
154 /* i2c bus recovery routines */
155 static int get_scl_gpio_value(struct i2c_adapter *adap)
157 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
160 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
162 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
165 static int get_sda_gpio_value(struct i2c_adapter *adap)
167 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
170 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
172 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
175 static int i2c_generic_bus_free(struct i2c_adapter *adap)
177 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
178 int ret = -EOPNOTSUPP;
180 if (bri->get_bus_free)
181 ret = bri->get_bus_free(adap);
182 else if (bri->get_sda)
183 ret = bri->get_sda(adap);
188 return ret ? 0 : -EBUSY;
192 * We are generating clock pulses. ndelay() determines durating of clk pulses.
193 * We will generate clock with rate 100 KHz and so duration of both clock levels
194 * is: delay in ns = (10^6 / 100) / 2
196 #define RECOVERY_NDELAY 5000
197 #define RECOVERY_CLK_CNT 9
199 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
201 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
202 int i = 0, scl = 1, ret = 0;
204 if (bri->prepare_recovery)
205 bri->prepare_recovery(adap);
207 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
210 * If we can set SDA, we will always create a STOP to ensure additional
211 * pulses will do no harm. This is achieved by letting SDA follow SCL
212 * half a cycle later. Check the 'incomplete_write_byte' fault injector
213 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
214 * here for simplicity.
216 bri->set_scl(adap, scl);
217 ndelay(RECOVERY_NDELAY);
219 bri->set_sda(adap, scl);
220 ndelay(RECOVERY_NDELAY / 2);
223 * By this time SCL is high, as we need to give 9 falling-rising edges
225 while (i++ < RECOVERY_CLK_CNT * 2) {
227 /* SCL shouldn't be low here */
228 if (!bri->get_scl(adap)) {
230 "SCL is stuck low, exit recovery\n");
237 bri->set_scl(adap, scl);
238 /* Creating STOP again, see above */
240 /* Honour minimum tsu:sto */
241 ndelay(RECOVERY_NDELAY);
243 /* Honour minimum tf and thd:dat */
244 ndelay(RECOVERY_NDELAY / 2);
247 bri->set_sda(adap, scl);
248 ndelay(RECOVERY_NDELAY / 2);
251 ret = i2c_generic_bus_free(adap);
257 /* If we can't check bus status, assume recovery worked */
258 if (ret == -EOPNOTSUPP)
261 if (bri->unprepare_recovery)
262 bri->unprepare_recovery(adap);
264 pinctrl_select_state(bri->pinctrl, bri->pins_default);
268 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
270 int i2c_recover_bus(struct i2c_adapter *adap)
272 if (!adap->bus_recovery_info)
275 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
276 return adap->bus_recovery_info->recover_bus(adap);
278 EXPORT_SYMBOL_GPL(i2c_recover_bus);
280 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
282 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
283 struct device *dev = &adap->dev;
284 struct pinctrl *p = bri->pinctrl;
287 * we can't change states without pinctrl, so remove the states if
291 bri->pins_default = NULL;
292 bri->pins_gpio = NULL;
296 if (!bri->pins_default) {
297 bri->pins_default = pinctrl_lookup_state(p,
298 PINCTRL_STATE_DEFAULT);
299 if (IS_ERR(bri->pins_default)) {
300 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
301 bri->pins_default = NULL;
304 if (!bri->pins_gpio) {
305 bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
306 if (IS_ERR(bri->pins_gpio))
307 bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
309 if (IS_ERR(bri->pins_gpio)) {
310 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
311 bri->pins_gpio = NULL;
315 /* for pinctrl state changes, we need all the information */
316 if (bri->pins_default && bri->pins_gpio) {
317 dev_info(dev, "using pinctrl states for GPIO recovery");
320 bri->pins_default = NULL;
321 bri->pins_gpio = NULL;
325 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
327 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
328 struct device *dev = &adap->dev;
329 struct gpio_desc *gpiod;
333 * don't touch the recovery information if the driver is not using
334 * generic SCL recovery
336 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
340 * pins might be taken as GPIO, so we should inform pinctrl about
341 * this and move the state to GPIO
344 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
347 * if there is incomplete or no recovery information, see if generic
348 * GPIO recovery is available
350 if (!bri->scl_gpiod) {
351 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
352 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
354 goto cleanup_pinctrl_state;
356 if (!IS_ERR(gpiod)) {
357 bri->scl_gpiod = gpiod;
358 bri->recover_bus = i2c_generic_scl_recovery;
359 dev_info(dev, "using generic GPIOs for recovery\n");
363 /* SDA GPIOD line is optional, so we care about DEFER only */
364 if (!bri->sda_gpiod) {
366 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
369 gpiod_direction_output(bri->scl_gpiod, 0);
371 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
373 /* Wait a bit in case of a SDA glitch, and then release SCL. */
375 gpiod_direction_output(bri->scl_gpiod, 1);
377 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
379 goto cleanup_pinctrl_state;
382 bri->sda_gpiod = gpiod;
385 cleanup_pinctrl_state:
386 /* change the state of the pins back to their default state */
388 pinctrl_select_state(bri->pinctrl, bri->pins_default);
393 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
395 i2c_gpio_init_pinctrl_recovery(adap);
396 return i2c_gpio_init_generic_recovery(adap);
399 static int i2c_init_recovery(struct i2c_adapter *adap)
401 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
402 char *err_str, *err_level = KERN_ERR;
407 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
408 return -EPROBE_DEFER;
410 if (!bri->recover_bus) {
411 err_str = "no suitable method provided";
412 err_level = KERN_DEBUG;
416 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
417 bri->get_scl = get_scl_gpio_value;
418 bri->set_scl = set_scl_gpio_value;
419 if (bri->sda_gpiod) {
420 bri->get_sda = get_sda_gpio_value;
421 /* FIXME: add proper flag instead of '0' once available */
422 if (gpiod_get_direction(bri->sda_gpiod) == 0)
423 bri->set_sda = set_sda_gpio_value;
425 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
426 /* Generic SCL recovery */
427 if (!bri->set_scl || !bri->get_scl) {
428 err_str = "no {get|set}_scl() found";
431 if (!bri->set_sda && !bri->get_sda) {
432 err_str = "either get_sda() or set_sda() needed";
439 dev_printk(err_level, &adap->dev, "Not using recovery: %s\n", err_str);
440 adap->bus_recovery_info = NULL;
445 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
447 struct i2c_adapter *adap = client->adapter;
450 if (!adap->host_notify_domain)
453 if (client->flags & I2C_CLIENT_TEN)
456 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
458 return irq > 0 ? irq : -ENXIO;
461 static int i2c_device_probe(struct device *dev)
463 struct i2c_client *client = i2c_verify_client(dev);
464 struct i2c_driver *driver;
470 client->irq = client->init_irq;
475 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
476 dev_dbg(dev, "Using Host Notify IRQ\n");
477 /* Keep adapter active when Host Notify is required */
478 pm_runtime_get_sync(&client->adapter->dev);
479 irq = i2c_smbus_host_notify_to_irq(client);
480 } else if (dev->of_node) {
481 irq = of_irq_get_byname(dev->of_node, "irq");
482 if (irq == -EINVAL || irq == -ENODATA)
483 irq = of_irq_get(dev->of_node, 0);
484 } else if (ACPI_COMPANION(dev)) {
485 irq = i2c_acpi_get_irq(client);
487 if (irq == -EPROBE_DEFER) {
489 goto put_sync_adapter;
498 driver = to_i2c_driver(dev->driver);
501 * An I2C ID table is not mandatory, if and only if, a suitable OF
502 * or ACPI ID table is supplied for the probing device.
504 if (!driver->id_table &&
505 !acpi_driver_match_device(dev, dev->driver) &&
506 !i2c_of_match_device(dev->driver->of_match_table, client)) {
508 goto put_sync_adapter;
511 if (client->flags & I2C_CLIENT_WAKE) {
514 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
515 if (wakeirq == -EPROBE_DEFER) {
517 goto put_sync_adapter;
520 device_init_wakeup(&client->dev, true);
522 if (wakeirq > 0 && wakeirq != client->irq)
523 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
524 else if (client->irq > 0)
525 status = dev_pm_set_wake_irq(dev, client->irq);
530 dev_warn(&client->dev, "failed to set up wakeup irq\n");
533 dev_dbg(dev, "probe\n");
535 status = of_clk_set_defaults(dev->of_node, false);
537 goto err_clear_wakeup_irq;
539 status = dev_pm_domain_attach(&client->dev, true);
541 goto err_clear_wakeup_irq;
543 client->devres_group_id = devres_open_group(&client->dev, NULL,
545 if (!client->devres_group_id) {
547 goto err_detach_pm_domain;
551 * When there are no more users of probe(),
552 * rename probe_new to probe.
554 if (driver->probe_new)
555 status = driver->probe_new(client);
556 else if (driver->probe)
557 status = driver->probe(client,
558 i2c_match_id(driver->id_table, client));
563 * Note that we are not closing the devres group opened above so
564 * even resources that were attached to the device after probe is
565 * run are released when i2c_device_remove() is executed. This is
566 * needed as some drivers would allocate additional resources,
567 * for example when updating firmware.
571 goto err_release_driver_resources;
575 err_release_driver_resources:
576 devres_release_group(&client->dev, client->devres_group_id);
577 err_detach_pm_domain:
578 dev_pm_domain_detach(&client->dev, true);
579 err_clear_wakeup_irq:
580 dev_pm_clear_wake_irq(&client->dev);
581 device_init_wakeup(&client->dev, false);
583 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
584 pm_runtime_put_sync(&client->adapter->dev);
589 static int i2c_device_remove(struct device *dev)
591 struct i2c_client *client = to_i2c_client(dev);
592 struct i2c_driver *driver;
594 driver = to_i2c_driver(dev->driver);
595 if (driver->remove) {
598 dev_dbg(dev, "remove\n");
600 status = driver->remove(client);
602 dev_warn(dev, "remove failed (%pe), will be ignored\n", ERR_PTR(status));
605 devres_release_group(&client->dev, client->devres_group_id);
607 dev_pm_domain_detach(&client->dev, true);
609 dev_pm_clear_wake_irq(&client->dev);
610 device_init_wakeup(&client->dev, false);
613 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
614 pm_runtime_put(&client->adapter->dev);
616 /* return always 0 because there is WIP to make remove-functions void */
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);
632 static void i2c_client_dev_release(struct device *dev)
634 kfree(to_i2c_client(dev));
638 name_show(struct device *dev, struct device_attribute *attr, char *buf)
640 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
641 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
643 static DEVICE_ATTR_RO(name);
646 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
648 struct i2c_client *client = to_i2c_client(dev);
651 len = of_device_modalias(dev, buf, PAGE_SIZE);
655 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
659 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
661 static DEVICE_ATTR_RO(modalias);
663 static struct attribute *i2c_dev_attrs[] = {
665 /* modalias helps coldplug: modprobe $(cat .../modalias) */
666 &dev_attr_modalias.attr,
669 ATTRIBUTE_GROUPS(i2c_dev);
671 struct bus_type i2c_bus_type = {
673 .match = i2c_device_match,
674 .probe = i2c_device_probe,
675 .remove = i2c_device_remove,
676 .shutdown = i2c_device_shutdown,
678 EXPORT_SYMBOL_GPL(i2c_bus_type);
680 struct device_type i2c_client_type = {
681 .groups = i2c_dev_groups,
682 .uevent = i2c_device_uevent,
683 .release = i2c_client_dev_release,
685 EXPORT_SYMBOL_GPL(i2c_client_type);
689 * i2c_verify_client - return parameter as i2c_client, or NULL
690 * @dev: device, probably from some driver model iterator
692 * When traversing the driver model tree, perhaps using driver model
693 * iterators like @device_for_each_child(), you can't assume very much
694 * about the nodes you find. Use this function to avoid oopses caused
695 * by wrongly treating some non-I2C device as an i2c_client.
697 struct i2c_client *i2c_verify_client(struct device *dev)
699 return (dev->type == &i2c_client_type)
703 EXPORT_SYMBOL(i2c_verify_client);
706 /* Return a unique address which takes the flags of the client into account */
707 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
709 unsigned short addr = client->addr;
711 /* For some client flags, add an arbitrary offset to avoid collisions */
712 if (client->flags & I2C_CLIENT_TEN)
713 addr |= I2C_ADDR_OFFSET_TEN_BIT;
715 if (client->flags & I2C_CLIENT_SLAVE)
716 addr |= I2C_ADDR_OFFSET_SLAVE;
721 /* This is a permissive address validity check, I2C address map constraints
722 * are purposely not enforced, except for the general call address. */
723 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
725 if (flags & I2C_CLIENT_TEN) {
726 /* 10-bit address, all values are valid */
730 /* 7-bit address, reject the general call address */
731 if (addr == 0x00 || addr > 0x7f)
737 /* And this is a strict address validity check, used when probing. If a
738 * device uses a reserved address, then it shouldn't be probed. 7-bit
739 * addressing is assumed, 10-bit address devices are rare and should be
740 * explicitly enumerated. */
741 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
744 * Reserved addresses per I2C specification:
745 * 0x00 General call address / START byte
747 * 0x02 Reserved for different bus format
748 * 0x03 Reserved for future purposes
749 * 0x04-0x07 Hs-mode master code
750 * 0x78-0x7b 10-bit slave addressing
751 * 0x7c-0x7f Reserved for future purposes
753 if (addr < 0x08 || addr > 0x77)
758 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
760 struct i2c_client *client = i2c_verify_client(dev);
761 int addr = *(int *)addrp;
763 if (client && i2c_encode_flags_to_addr(client) == addr)
768 /* walk up mux tree */
769 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
771 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
774 result = device_for_each_child(&adapter->dev, &addr,
775 __i2c_check_addr_busy);
777 if (!result && parent)
778 result = i2c_check_mux_parents(parent, addr);
783 /* recurse down mux tree */
784 static int i2c_check_mux_children(struct device *dev, void *addrp)
788 if (dev->type == &i2c_adapter_type)
789 result = device_for_each_child(dev, addrp,
790 i2c_check_mux_children);
792 result = __i2c_check_addr_busy(dev, addrp);
797 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
799 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
803 result = i2c_check_mux_parents(parent, addr);
806 result = device_for_each_child(&adapter->dev, &addr,
807 i2c_check_mux_children);
813 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
814 * @adapter: Target I2C bus segment
815 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
816 * locks only this branch in the adapter tree
818 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
821 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
825 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
826 * @adapter: Target I2C bus segment
827 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
828 * trylocks only this branch in the adapter tree
830 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
833 return rt_mutex_trylock(&adapter->bus_lock);
837 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
838 * @adapter: Target I2C bus segment
839 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
840 * unlocks only this branch in the adapter tree
842 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
845 rt_mutex_unlock(&adapter->bus_lock);
848 static void i2c_dev_set_name(struct i2c_adapter *adap,
849 struct i2c_client *client,
850 struct i2c_board_info const *info)
852 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
854 if (info && info->dev_name) {
855 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
860 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
864 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
865 i2c_encode_flags_to_addr(client));
868 int i2c_dev_irq_from_resources(const struct resource *resources,
869 unsigned int num_resources)
871 struct irq_data *irqd;
874 for (i = 0; i < num_resources; i++) {
875 const struct resource *r = &resources[i];
877 if (resource_type(r) != IORESOURCE_IRQ)
880 if (r->flags & IORESOURCE_BITS) {
881 irqd = irq_get_irq_data(r->start);
885 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
895 * i2c_new_client_device - instantiate an i2c device
896 * @adap: the adapter managing the device
897 * @info: describes one I2C device; bus_num is ignored
900 * Create an i2c device. Binding is handled through driver model
901 * probe()/remove() methods. A driver may be bound to this device when we
902 * return from this function, or any later moment (e.g. maybe hotplugging will
903 * load the driver module). This call is not appropriate for use by mainboard
904 * initialization logic, which usually runs during an arch_initcall() long
905 * before any i2c_adapter could exist.
907 * This returns the new i2c client, which may be saved for later use with
908 * i2c_unregister_device(); or an ERR_PTR to describe the error.
911 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
913 struct i2c_client *client;
916 client = kzalloc(sizeof *client, GFP_KERNEL);
918 return ERR_PTR(-ENOMEM);
920 client->adapter = adap;
922 client->dev.platform_data = info->platform_data;
923 client->flags = info->flags;
924 client->addr = info->addr;
926 client->init_irq = info->irq;
927 if (!client->init_irq)
928 client->init_irq = i2c_dev_irq_from_resources(info->resources,
929 info->num_resources);
931 strlcpy(client->name, info->type, sizeof(client->name));
933 status = i2c_check_addr_validity(client->addr, client->flags);
935 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
936 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
940 /* Check for address business */
941 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
945 client->dev.parent = &client->adapter->dev;
946 client->dev.bus = &i2c_bus_type;
947 client->dev.type = &i2c_client_type;
948 client->dev.of_node = of_node_get(info->of_node);
949 client->dev.fwnode = info->fwnode;
951 i2c_dev_set_name(adap, client, info);
954 status = device_add_software_node(&client->dev, info->swnode);
957 "Failed to add software node to client %s: %d\n",
958 client->name, status);
959 goto out_err_put_of_node;
963 status = device_register(&client->dev);
965 goto out_remove_swnode;
967 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
968 client->name, dev_name(&client->dev));
973 device_remove_software_node(&client->dev);
975 of_node_put(info->of_node);
978 "Failed to register i2c client %s at 0x%02x (%d)\n",
979 client->name, client->addr, status);
982 return ERR_PTR(status);
984 EXPORT_SYMBOL_GPL(i2c_new_client_device);
987 * i2c_unregister_device - reverse effect of i2c_new_*_device()
988 * @client: value returned from i2c_new_*_device()
991 void i2c_unregister_device(struct i2c_client *client)
993 if (IS_ERR_OR_NULL(client))
996 if (client->dev.of_node) {
997 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
998 of_node_put(client->dev.of_node);
1001 if (ACPI_COMPANION(&client->dev))
1002 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1003 device_remove_software_node(&client->dev);
1004 device_unregister(&client->dev);
1006 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1009 static const struct i2c_device_id dummy_id[] = {
1014 static int dummy_probe(struct i2c_client *client,
1015 const struct i2c_device_id *id)
1020 static int dummy_remove(struct i2c_client *client)
1025 static struct i2c_driver dummy_driver = {
1026 .driver.name = "dummy",
1027 .probe = dummy_probe,
1028 .remove = dummy_remove,
1029 .id_table = dummy_id,
1033 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1034 * @adapter: the adapter managing the device
1035 * @address: seven bit address to be used
1036 * Context: can sleep
1038 * This returns an I2C client bound to the "dummy" driver, intended for use
1039 * with devices that consume multiple addresses. Examples of such chips
1040 * include various EEPROMS (like 24c04 and 24c08 models).
1042 * These dummy devices have two main uses. First, most I2C and SMBus calls
1043 * except i2c_transfer() need a client handle; the dummy will be that handle.
1044 * And second, this prevents the specified address from being bound to a
1047 * This returns the new i2c client, which should be saved for later use with
1048 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1050 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1052 struct i2c_board_info info = {
1053 I2C_BOARD_INFO("dummy", address),
1056 return i2c_new_client_device(adapter, &info);
1058 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1060 static void devm_i2c_release_dummy(void *client)
1062 i2c_unregister_device(client);
1066 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1067 * @dev: device the managed resource is bound to
1068 * @adapter: the adapter managing the device
1069 * @address: seven bit address to be used
1070 * Context: can sleep
1072 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1073 * new i2c client or an ERR_PTR in case of an error.
1075 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1076 struct i2c_adapter *adapter,
1079 struct i2c_client *client;
1082 client = i2c_new_dummy_device(adapter, address);
1086 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1088 return ERR_PTR(ret);
1092 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1095 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1096 * and create the associated device
1097 * @client: Handle to the primary client
1098 * @name: Handle to specify which secondary address to get
1099 * @default_addr: Used as a fallback if no secondary address was specified
1100 * Context: can sleep
1102 * I2C clients can be composed of multiple I2C slaves bound together in a single
1103 * component. The I2C client driver then binds to the master I2C slave and needs
1104 * to create I2C dummy clients to communicate with all the other slaves.
1106 * This function creates and returns an I2C dummy client whose I2C address is
1107 * retrieved from the platform firmware based on the given slave name. If no
1108 * address is specified by the firmware default_addr is used.
1110 * On DT-based platforms the address is retrieved from the "reg" property entry
1111 * cell whose "reg-names" value matches the slave name.
1113 * This returns the new i2c client, which should be saved for later use with
1114 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1116 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1120 struct device_node *np = client->dev.of_node;
1121 u32 addr = default_addr;
1125 i = of_property_match_string(np, "reg-names", name);
1127 of_property_read_u32_index(np, "reg", i, &addr);
1130 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1131 return i2c_new_dummy_device(client->adapter, addr);
1133 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1135 /* ------------------------------------------------------------------------- */
1137 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1139 static void i2c_adapter_dev_release(struct device *dev)
1141 struct i2c_adapter *adap = to_i2c_adapter(dev);
1142 complete(&adap->dev_released);
1145 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1147 unsigned int depth = 0;
1149 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1152 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1153 "adapter depth exceeds lockdep subclass limit\n");
1157 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1160 * Let users instantiate I2C devices through sysfs. This can be used when
1161 * platform initialization code doesn't contain the proper data for
1162 * whatever reason. Also useful for drivers that do device detection and
1163 * detection fails, either because the device uses an unexpected address,
1164 * or this is a compatible device with different ID register values.
1166 * Parameter checking may look overzealous, but we really don't want
1167 * the user to provide incorrect parameters.
1170 new_device_store(struct device *dev, struct device_attribute *attr,
1171 const char *buf, size_t count)
1173 struct i2c_adapter *adap = to_i2c_adapter(dev);
1174 struct i2c_board_info info;
1175 struct i2c_client *client;
1179 memset(&info, 0, sizeof(struct i2c_board_info));
1181 blank = strchr(buf, ' ');
1183 dev_err(dev, "%s: Missing parameters\n", "new_device");
1186 if (blank - buf > I2C_NAME_SIZE - 1) {
1187 dev_err(dev, "%s: Invalid device name\n", "new_device");
1190 memcpy(info.type, buf, blank - buf);
1192 /* Parse remaining parameters, reject extra parameters */
1193 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1195 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1198 if (res > 1 && end != '\n') {
1199 dev_err(dev, "%s: Extra parameters\n", "new_device");
1203 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1204 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1205 info.flags |= I2C_CLIENT_TEN;
1208 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1209 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1210 info.flags |= I2C_CLIENT_SLAVE;
1213 client = i2c_new_client_device(adap, &info);
1215 return PTR_ERR(client);
1217 /* Keep track of the added device */
1218 mutex_lock(&adap->userspace_clients_lock);
1219 list_add_tail(&client->detected, &adap->userspace_clients);
1220 mutex_unlock(&adap->userspace_clients_lock);
1221 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1222 info.type, info.addr);
1226 static DEVICE_ATTR_WO(new_device);
1229 * And of course let the users delete the devices they instantiated, if
1230 * they got it wrong. This interface can only be used to delete devices
1231 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1232 * don't delete devices to which some kernel code still has references.
1234 * Parameter checking may look overzealous, but we really don't want
1235 * the user to delete the wrong device.
1238 delete_device_store(struct device *dev, struct device_attribute *attr,
1239 const char *buf, size_t count)
1241 struct i2c_adapter *adap = to_i2c_adapter(dev);
1242 struct i2c_client *client, *next;
1243 unsigned short addr;
1247 /* Parse parameters, reject extra parameters */
1248 res = sscanf(buf, "%hi%c", &addr, &end);
1250 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1253 if (res > 1 && end != '\n') {
1254 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1258 /* Make sure the device was added through sysfs */
1260 mutex_lock_nested(&adap->userspace_clients_lock,
1261 i2c_adapter_depth(adap));
1262 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1264 if (i2c_encode_flags_to_addr(client) == addr) {
1265 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1266 "delete_device", client->name, client->addr);
1268 list_del(&client->detected);
1269 i2c_unregister_device(client);
1274 mutex_unlock(&adap->userspace_clients_lock);
1277 dev_err(dev, "%s: Can't find device in list\n",
1281 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1282 delete_device_store);
1284 static struct attribute *i2c_adapter_attrs[] = {
1285 &dev_attr_name.attr,
1286 &dev_attr_new_device.attr,
1287 &dev_attr_delete_device.attr,
1290 ATTRIBUTE_GROUPS(i2c_adapter);
1292 struct device_type i2c_adapter_type = {
1293 .groups = i2c_adapter_groups,
1294 .release = i2c_adapter_dev_release,
1296 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1299 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1300 * @dev: device, probably from some driver model iterator
1302 * When traversing the driver model tree, perhaps using driver model
1303 * iterators like @device_for_each_child(), you can't assume very much
1304 * about the nodes you find. Use this function to avoid oopses caused
1305 * by wrongly treating some non-I2C device as an i2c_adapter.
1307 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1309 return (dev->type == &i2c_adapter_type)
1310 ? to_i2c_adapter(dev)
1313 EXPORT_SYMBOL(i2c_verify_adapter);
1315 #ifdef CONFIG_I2C_COMPAT
1316 static struct class_compat *i2c_adapter_compat_class;
1319 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1321 struct i2c_devinfo *devinfo;
1323 down_read(&__i2c_board_lock);
1324 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1325 if (devinfo->busnum == adapter->nr &&
1326 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1327 dev_err(&adapter->dev,
1328 "Can't create device at 0x%02x\n",
1329 devinfo->board_info.addr);
1331 up_read(&__i2c_board_lock);
1334 static int i2c_do_add_adapter(struct i2c_driver *driver,
1335 struct i2c_adapter *adap)
1337 /* Detect supported devices on that bus, and instantiate them */
1338 i2c_detect(adap, driver);
1343 static int __process_new_adapter(struct device_driver *d, void *data)
1345 return i2c_do_add_adapter(to_i2c_driver(d), data);
1348 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1349 .lock_bus = i2c_adapter_lock_bus,
1350 .trylock_bus = i2c_adapter_trylock_bus,
1351 .unlock_bus = i2c_adapter_unlock_bus,
1354 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1356 struct irq_domain *domain = adap->host_notify_domain;
1357 irq_hw_number_t hwirq;
1362 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1363 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1365 irq_domain_remove(domain);
1366 adap->host_notify_domain = NULL;
1369 static int i2c_host_notify_irq_map(struct irq_domain *h,
1371 irq_hw_number_t hw_irq_num)
1373 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1378 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1379 .map = i2c_host_notify_irq_map,
1382 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1384 struct irq_domain *domain;
1386 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1389 domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1390 I2C_ADDR_7BITS_COUNT,
1391 &i2c_host_notify_irq_ops, adap);
1395 adap->host_notify_domain = domain;
1401 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1403 * @adap: the adapter
1404 * @addr: the I2C address of the notifying device
1405 * Context: can't sleep
1407 * Helper function to be called from an I2C bus driver's interrupt
1408 * handler. It will schedule the Host Notify IRQ.
1410 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1417 irq = irq_find_mapping(adap->host_notify_domain, addr);
1421 generic_handle_irq(irq);
1425 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1427 static int i2c_register_adapter(struct i2c_adapter *adap)
1431 /* Can't register until after driver model init */
1432 if (WARN_ON(!is_registered)) {
1438 if (WARN(!adap->name[0], "i2c adapter has no name"))
1442 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1446 if (!adap->lock_ops)
1447 adap->lock_ops = &i2c_adapter_lock_ops;
1449 adap->locked_flags = 0;
1450 rt_mutex_init(&adap->bus_lock);
1451 rt_mutex_init(&adap->mux_lock);
1452 mutex_init(&adap->userspace_clients_lock);
1453 INIT_LIST_HEAD(&adap->userspace_clients);
1455 /* Set default timeout to 1 second if not already set */
1456 if (adap->timeout == 0)
1459 /* register soft irqs for Host Notify */
1460 res = i2c_setup_host_notify_irq_domain(adap);
1462 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1467 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1468 adap->dev.bus = &i2c_bus_type;
1469 adap->dev.type = &i2c_adapter_type;
1470 res = device_register(&adap->dev);
1472 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1476 res = of_i2c_setup_smbus_alert(adap);
1480 pm_runtime_no_callbacks(&adap->dev);
1481 pm_suspend_ignore_children(&adap->dev, true);
1482 pm_runtime_enable(&adap->dev);
1484 res = i2c_init_recovery(adap);
1485 if (res == -EPROBE_DEFER)
1488 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1490 #ifdef CONFIG_I2C_COMPAT
1491 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1494 dev_warn(&adap->dev,
1495 "Failed to create compatibility class link\n");
1498 /* create pre-declared device nodes */
1499 of_i2c_register_devices(adap);
1500 i2c_acpi_install_space_handler(adap);
1501 i2c_acpi_register_devices(adap);
1503 if (adap->nr < __i2c_first_dynamic_bus_num)
1504 i2c_scan_static_board_info(adap);
1506 /* Notify drivers */
1507 mutex_lock(&core_lock);
1508 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1509 mutex_unlock(&core_lock);
1514 init_completion(&adap->dev_released);
1515 device_unregister(&adap->dev);
1516 wait_for_completion(&adap->dev_released);
1518 mutex_lock(&core_lock);
1519 idr_remove(&i2c_adapter_idr, adap->nr);
1520 mutex_unlock(&core_lock);
1525 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1526 * @adap: the adapter to register (with adap->nr initialized)
1527 * Context: can sleep
1529 * See i2c_add_numbered_adapter() for details.
1531 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1535 mutex_lock(&core_lock);
1536 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1537 mutex_unlock(&core_lock);
1538 if (WARN(id < 0, "couldn't get idr"))
1539 return id == -ENOSPC ? -EBUSY : id;
1541 return i2c_register_adapter(adap);
1545 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1546 * @adapter: the adapter to add
1547 * Context: can sleep
1549 * This routine is used to declare an I2C adapter when its bus number
1550 * doesn't matter or when its bus number is specified by an dt alias.
1551 * Examples of bases when the bus number doesn't matter: I2C adapters
1552 * dynamically added by USB links or PCI plugin cards.
1554 * When this returns zero, a new bus number was allocated and stored
1555 * in adap->nr, and the specified adapter became available for clients.
1556 * Otherwise, a negative errno value is returned.
1558 int i2c_add_adapter(struct i2c_adapter *adapter)
1560 struct device *dev = &adapter->dev;
1564 id = of_alias_get_id(dev->of_node, "i2c");
1567 return __i2c_add_numbered_adapter(adapter);
1571 mutex_lock(&core_lock);
1572 id = idr_alloc(&i2c_adapter_idr, adapter,
1573 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1574 mutex_unlock(&core_lock);
1575 if (WARN(id < 0, "couldn't get idr"))
1580 return i2c_register_adapter(adapter);
1582 EXPORT_SYMBOL(i2c_add_adapter);
1585 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1586 * @adap: the adapter to register (with adap->nr initialized)
1587 * Context: can sleep
1589 * This routine is used to declare an I2C adapter when its bus number
1590 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1591 * or otherwise built in to the system's mainboard, and where i2c_board_info
1592 * is used to properly configure I2C devices.
1594 * If the requested bus number is set to -1, then this function will behave
1595 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1597 * If no devices have pre-been declared for this bus, then be sure to
1598 * register the adapter before any dynamically allocated ones. Otherwise
1599 * the required bus ID may not be available.
1601 * When this returns zero, the specified adapter became available for
1602 * clients using the bus number provided in adap->nr. Also, the table
1603 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1604 * and the appropriate driver model device nodes are created. Otherwise, a
1605 * negative errno value is returned.
1607 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1609 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1610 return i2c_add_adapter(adap);
1612 return __i2c_add_numbered_adapter(adap);
1614 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1616 static void i2c_do_del_adapter(struct i2c_driver *driver,
1617 struct i2c_adapter *adapter)
1619 struct i2c_client *client, *_n;
1621 /* Remove the devices we created ourselves as the result of hardware
1622 * probing (using a driver's detect method) */
1623 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1624 if (client->adapter == adapter) {
1625 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1626 client->name, client->addr);
1627 list_del(&client->detected);
1628 i2c_unregister_device(client);
1633 static int __unregister_client(struct device *dev, void *dummy)
1635 struct i2c_client *client = i2c_verify_client(dev);
1636 if (client && strcmp(client->name, "dummy"))
1637 i2c_unregister_device(client);
1641 static int __unregister_dummy(struct device *dev, void *dummy)
1643 struct i2c_client *client = i2c_verify_client(dev);
1644 i2c_unregister_device(client);
1648 static int __process_removed_adapter(struct device_driver *d, void *data)
1650 i2c_do_del_adapter(to_i2c_driver(d), data);
1655 * i2c_del_adapter - unregister I2C adapter
1656 * @adap: the adapter being unregistered
1657 * Context: can sleep
1659 * This unregisters an I2C adapter which was previously registered
1660 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1662 void i2c_del_adapter(struct i2c_adapter *adap)
1664 struct i2c_adapter *found;
1665 struct i2c_client *client, *next;
1667 /* First make sure that this adapter was ever added */
1668 mutex_lock(&core_lock);
1669 found = idr_find(&i2c_adapter_idr, adap->nr);
1670 mutex_unlock(&core_lock);
1671 if (found != adap) {
1672 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1676 i2c_acpi_remove_space_handler(adap);
1677 /* Tell drivers about this removal */
1678 mutex_lock(&core_lock);
1679 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1680 __process_removed_adapter);
1681 mutex_unlock(&core_lock);
1683 /* Remove devices instantiated from sysfs */
1684 mutex_lock_nested(&adap->userspace_clients_lock,
1685 i2c_adapter_depth(adap));
1686 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1688 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1690 list_del(&client->detected);
1691 i2c_unregister_device(client);
1693 mutex_unlock(&adap->userspace_clients_lock);
1695 /* Detach any active clients. This can't fail, thus we do not
1696 * check the returned value. This is a two-pass process, because
1697 * we can't remove the dummy devices during the first pass: they
1698 * could have been instantiated by real devices wishing to clean
1699 * them up properly, so we give them a chance to do that first. */
1700 device_for_each_child(&adap->dev, NULL, __unregister_client);
1701 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1703 #ifdef CONFIG_I2C_COMPAT
1704 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1708 /* device name is gone after device_unregister */
1709 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1711 pm_runtime_disable(&adap->dev);
1713 i2c_host_notify_irq_teardown(adap);
1715 /* wait until all references to the device are gone
1717 * FIXME: This is old code and should ideally be replaced by an
1718 * alternative which results in decoupling the lifetime of the struct
1719 * device from the i2c_adapter, like spi or netdev do. Any solution
1720 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1722 init_completion(&adap->dev_released);
1723 device_unregister(&adap->dev);
1724 wait_for_completion(&adap->dev_released);
1727 mutex_lock(&core_lock);
1728 idr_remove(&i2c_adapter_idr, adap->nr);
1729 mutex_unlock(&core_lock);
1731 /* Clear the device structure in case this adapter is ever going to be
1733 memset(&adap->dev, 0, sizeof(adap->dev));
1735 EXPORT_SYMBOL(i2c_del_adapter);
1737 static void devm_i2c_del_adapter(void *adapter)
1739 i2c_del_adapter(adapter);
1743 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1744 * @dev: managing device for adding this I2C adapter
1745 * @adapter: the adapter to add
1746 * Context: can sleep
1748 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1749 * but the adapter will be auto deleted on driver detach.
1751 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1755 ret = i2c_add_adapter(adapter);
1759 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1761 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1763 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1764 u32 def_val, bool use_def)
1768 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1770 *cur_val_p = def_val;
1772 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1776 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1777 * @dev: The device to scan for I2C timing properties
1778 * @t: the i2c_timings struct to be filled with values
1779 * @use_defaults: bool to use sane defaults derived from the I2C specification
1780 * when properties are not found, otherwise don't update
1782 * Scan the device for the generic I2C properties describing timing parameters
1783 * for the signal and fill the given struct with the results. If a property was
1784 * not found and use_defaults was true, then maximum timings are assumed which
1785 * are derived from the I2C specification. If use_defaults is not used, the
1786 * results will be as before, so drivers can apply their own defaults before
1787 * calling this helper. The latter is mainly intended for avoiding regressions
1788 * of existing drivers which want to switch to this function. New drivers
1789 * almost always should use the defaults.
1791 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1793 bool u = use_defaults;
1796 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1797 I2C_MAX_STANDARD_MODE_FREQ, u);
1799 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1800 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1801 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1803 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1804 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1806 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1807 &t->scl_int_delay_ns, 0, u);
1808 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1810 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1811 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1812 &t->digital_filter_width_ns, 0, u);
1813 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1814 &t->analog_filter_cutoff_freq_hz, 0, u);
1816 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1818 /* ------------------------------------------------------------------------- */
1820 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1824 mutex_lock(&core_lock);
1825 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1826 mutex_unlock(&core_lock);
1830 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1832 static int __process_new_driver(struct device *dev, void *data)
1834 if (dev->type != &i2c_adapter_type)
1836 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1840 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1841 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1844 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1848 /* Can't register until after driver model init */
1849 if (WARN_ON(!is_registered))
1852 /* add the driver to the list of i2c drivers in the driver core */
1853 driver->driver.owner = owner;
1854 driver->driver.bus = &i2c_bus_type;
1855 INIT_LIST_HEAD(&driver->clients);
1857 /* When registration returns, the driver core
1858 * will have called probe() for all matching-but-unbound devices.
1860 res = driver_register(&driver->driver);
1864 pr_debug("driver [%s] registered\n", driver->driver.name);
1866 /* Walk the adapters that are already present */
1867 i2c_for_each_dev(driver, __process_new_driver);
1871 EXPORT_SYMBOL(i2c_register_driver);
1873 static int __process_removed_driver(struct device *dev, void *data)
1875 if (dev->type == &i2c_adapter_type)
1876 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1881 * i2c_del_driver - unregister I2C driver
1882 * @driver: the driver being unregistered
1883 * Context: can sleep
1885 void i2c_del_driver(struct i2c_driver *driver)
1887 i2c_for_each_dev(driver, __process_removed_driver);
1889 driver_unregister(&driver->driver);
1890 pr_debug("driver [%s] unregistered\n", driver->driver.name);
1892 EXPORT_SYMBOL(i2c_del_driver);
1894 /* ------------------------------------------------------------------------- */
1896 struct i2c_cmd_arg {
1901 static int i2c_cmd(struct device *dev, void *_arg)
1903 struct i2c_client *client = i2c_verify_client(dev);
1904 struct i2c_cmd_arg *arg = _arg;
1905 struct i2c_driver *driver;
1907 if (!client || !client->dev.driver)
1910 driver = to_i2c_driver(client->dev.driver);
1911 if (driver->command)
1912 driver->command(client, arg->cmd, arg->arg);
1916 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1918 struct i2c_cmd_arg cmd_arg;
1922 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1924 EXPORT_SYMBOL(i2c_clients_command);
1926 static int __init i2c_init(void)
1930 retval = of_alias_get_highest_id("i2c");
1932 down_write(&__i2c_board_lock);
1933 if (retval >= __i2c_first_dynamic_bus_num)
1934 __i2c_first_dynamic_bus_num = retval + 1;
1935 up_write(&__i2c_board_lock);
1937 retval = bus_register(&i2c_bus_type);
1941 is_registered = true;
1943 #ifdef CONFIG_I2C_COMPAT
1944 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1945 if (!i2c_adapter_compat_class) {
1950 retval = i2c_add_driver(&dummy_driver);
1954 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1955 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1956 if (IS_ENABLED(CONFIG_ACPI))
1957 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1962 #ifdef CONFIG_I2C_COMPAT
1963 class_compat_unregister(i2c_adapter_compat_class);
1966 is_registered = false;
1967 bus_unregister(&i2c_bus_type);
1971 static void __exit i2c_exit(void)
1973 if (IS_ENABLED(CONFIG_ACPI))
1974 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1975 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1976 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1977 i2c_del_driver(&dummy_driver);
1978 #ifdef CONFIG_I2C_COMPAT
1979 class_compat_unregister(i2c_adapter_compat_class);
1981 bus_unregister(&i2c_bus_type);
1982 tracepoint_synchronize_unregister();
1985 /* We must initialize early, because some subsystems register i2c drivers
1986 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1988 postcore_initcall(i2c_init);
1989 module_exit(i2c_exit);
1991 /* ----------------------------------------------------
1992 * the functional interface to the i2c busses.
1993 * ----------------------------------------------------
1996 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1997 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1999 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2001 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2002 err_msg, msg->addr, msg->len,
2003 msg->flags & I2C_M_RD ? "read" : "write");
2007 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2009 const struct i2c_adapter_quirks *q = adap->quirks;
2010 int max_num = q->max_num_msgs, i;
2011 bool do_len_check = true;
2013 if (q->flags & I2C_AQ_COMB) {
2016 /* special checks for combined messages */
2018 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2019 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2021 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2022 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2024 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2025 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2027 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2028 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2030 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2031 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2033 do_len_check = false;
2037 if (i2c_quirk_exceeded(num, max_num))
2038 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2040 for (i = 0; i < num; i++) {
2041 u16 len = msgs[i].len;
2043 if (msgs[i].flags & I2C_M_RD) {
2044 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2045 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2047 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2048 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2050 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2051 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2053 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2054 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2062 * __i2c_transfer - unlocked flavor of i2c_transfer
2063 * @adap: Handle to I2C bus
2064 * @msgs: One or more messages to execute before STOP is issued to
2065 * terminate the operation; each message begins with a START.
2066 * @num: Number of messages to be executed.
2068 * Returns negative errno, else the number of messages executed.
2070 * Adapter lock must be held when calling this function. No debug logging
2071 * takes place. adap->algo->master_xfer existence isn't checked.
2073 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2075 unsigned long orig_jiffies;
2078 if (WARN_ON(!msgs || num < 1))
2081 ret = __i2c_check_suspended(adap);
2085 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2089 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2090 * enabled. This is an efficient way of keeping the for-loop from
2091 * being executed when not needed.
2093 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2095 for (i = 0; i < num; i++)
2096 if (msgs[i].flags & I2C_M_RD)
2097 trace_i2c_read(adap, &msgs[i], i);
2099 trace_i2c_write(adap, &msgs[i], i);
2102 /* Retry automatically on arbitration loss */
2103 orig_jiffies = jiffies;
2104 for (ret = 0, try = 0; try <= adap->retries; try++) {
2105 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2106 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2108 ret = adap->algo->master_xfer(adap, msgs, num);
2112 if (time_after(jiffies, orig_jiffies + adap->timeout))
2116 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2118 for (i = 0; i < ret; i++)
2119 if (msgs[i].flags & I2C_M_RD)
2120 trace_i2c_reply(adap, &msgs[i], i);
2121 trace_i2c_result(adap, num, ret);
2126 EXPORT_SYMBOL(__i2c_transfer);
2129 * i2c_transfer - execute a single or combined I2C message
2130 * @adap: Handle to I2C bus
2131 * @msgs: One or more messages to execute before STOP is issued to
2132 * terminate the operation; each message begins with a START.
2133 * @num: Number of messages to be executed.
2135 * Returns negative errno, else the number of messages executed.
2137 * Note that there is no requirement that each message be sent to
2138 * the same slave address, although that is the most common model.
2140 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2144 if (!adap->algo->master_xfer) {
2145 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2149 /* REVISIT the fault reporting model here is weak:
2151 * - When we get an error after receiving N bytes from a slave,
2152 * there is no way to report "N".
2154 * - When we get a NAK after transmitting N bytes to a slave,
2155 * there is no way to report "N" ... or to let the master
2156 * continue executing the rest of this combined message, if
2157 * that's the appropriate response.
2159 * - When for example "num" is two and we successfully complete
2160 * the first message but get an error part way through the
2161 * second, it's unclear whether that should be reported as
2162 * one (discarding status on the second message) or errno
2163 * (discarding status on the first one).
2165 ret = __i2c_lock_bus_helper(adap);
2169 ret = __i2c_transfer(adap, msgs, num);
2170 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2174 EXPORT_SYMBOL(i2c_transfer);
2177 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2179 * @client: Handle to slave device
2180 * @buf: Where the data is stored
2181 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2182 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2184 * Returns negative errno, or else the number of bytes transferred.
2186 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2187 int count, u16 flags)
2190 struct i2c_msg msg = {
2191 .addr = client->addr,
2192 .flags = flags | (client->flags & I2C_M_TEN),
2197 ret = i2c_transfer(client->adapter, &msg, 1);
2200 * If everything went ok (i.e. 1 msg transferred), return #bytes
2201 * transferred, else error code.
2203 return (ret == 1) ? count : ret;
2205 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2208 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2209 * @client: The device to query
2210 * @id: The queried information
2212 * Returns negative errno on error, zero on success.
2214 int i2c_get_device_id(const struct i2c_client *client,
2215 struct i2c_device_identity *id)
2217 struct i2c_adapter *adap = client->adapter;
2218 union i2c_smbus_data raw_id;
2221 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2224 raw_id.block[0] = 3;
2225 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2226 I2C_SMBUS_READ, client->addr << 1,
2227 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2231 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2232 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2233 id->die_revision = raw_id.block[3] & 0x7;
2236 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2238 /* ----------------------------------------------------
2239 * the i2c address scanning function
2240 * Will not work for 10-bit addresses!
2241 * ----------------------------------------------------
2245 * Legacy default probe function, mostly relevant for SMBus. The default
2246 * probe method is a quick write, but it is known to corrupt the 24RF08
2247 * EEPROMs due to a state machine bug, and could also irreversibly
2248 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2249 * we use a short byte read instead. Also, some bus drivers don't implement
2250 * quick write, so we fallback to a byte read in that case too.
2251 * On x86, there is another special case for FSC hardware monitoring chips,
2252 * which want regular byte reads (address 0x73.) Fortunately, these are the
2253 * only known chips using this I2C address on PC hardware.
2254 * Returns 1 if probe succeeded, 0 if not.
2256 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2259 union i2c_smbus_data dummy;
2262 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2263 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2264 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2265 I2C_SMBUS_BYTE_DATA, &dummy);
2268 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2269 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2270 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2271 I2C_SMBUS_QUICK, NULL);
2272 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2273 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2274 I2C_SMBUS_BYTE, &dummy);
2276 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2284 static int i2c_detect_address(struct i2c_client *temp_client,
2285 struct i2c_driver *driver)
2287 struct i2c_board_info info;
2288 struct i2c_adapter *adapter = temp_client->adapter;
2289 int addr = temp_client->addr;
2292 /* Make sure the address is valid */
2293 err = i2c_check_7bit_addr_validity_strict(addr);
2295 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2300 /* Skip if already in use (7 bit, no need to encode flags) */
2301 if (i2c_check_addr_busy(adapter, addr))
2304 /* Make sure there is something at this address */
2305 if (!i2c_default_probe(adapter, addr))
2308 /* Finally call the custom detection function */
2309 memset(&info, 0, sizeof(struct i2c_board_info));
2311 err = driver->detect(temp_client, &info);
2313 /* -ENODEV is returned if the detection fails. We catch it
2314 here as this isn't an error. */
2315 return err == -ENODEV ? 0 : err;
2318 /* Consistency check */
2319 if (info.type[0] == '\0') {
2320 dev_err(&adapter->dev,
2321 "%s detection function provided no name for 0x%x\n",
2322 driver->driver.name, addr);
2324 struct i2c_client *client;
2326 /* Detection succeeded, instantiate the device */
2327 if (adapter->class & I2C_CLASS_DEPRECATED)
2328 dev_warn(&adapter->dev,
2329 "This adapter will soon drop class based instantiation of devices. "
2330 "Please make sure client 0x%02x gets instantiated by other means. "
2331 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2334 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2335 info.type, info.addr);
2336 client = i2c_new_client_device(adapter, &info);
2337 if (!IS_ERR(client))
2338 list_add_tail(&client->detected, &driver->clients);
2340 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2341 info.type, info.addr);
2346 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2348 const unsigned short *address_list;
2349 struct i2c_client *temp_client;
2352 address_list = driver->address_list;
2353 if (!driver->detect || !address_list)
2356 /* Warn that the adapter lost class based instantiation */
2357 if (adapter->class == I2C_CLASS_DEPRECATED) {
2358 dev_dbg(&adapter->dev,
2359 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2360 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2361 driver->driver.name);
2365 /* Stop here if the classes do not match */
2366 if (!(adapter->class & driver->class))
2369 /* Set up a temporary client to help detect callback */
2370 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2373 temp_client->adapter = adapter;
2375 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2376 dev_dbg(&adapter->dev,
2377 "found normal entry for adapter %d, addr 0x%02x\n",
2378 i2c_adapter_id(adapter), address_list[i]);
2379 temp_client->addr = address_list[i];
2380 err = i2c_detect_address(temp_client, driver);
2389 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2391 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2392 I2C_SMBUS_QUICK, NULL) >= 0;
2394 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2397 i2c_new_scanned_device(struct i2c_adapter *adap,
2398 struct i2c_board_info *info,
2399 unsigned short const *addr_list,
2400 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2405 probe = i2c_default_probe;
2407 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2408 /* Check address validity */
2409 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2410 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2415 /* Check address availability (7 bit, no need to encode flags) */
2416 if (i2c_check_addr_busy(adap, addr_list[i])) {
2418 "Address 0x%02x already in use, not probing\n",
2423 /* Test address responsiveness */
2424 if (probe(adap, addr_list[i]))
2428 if (addr_list[i] == I2C_CLIENT_END) {
2429 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2430 return ERR_PTR(-ENODEV);
2433 info->addr = addr_list[i];
2434 return i2c_new_client_device(adap, info);
2436 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2438 struct i2c_adapter *i2c_get_adapter(int nr)
2440 struct i2c_adapter *adapter;
2442 mutex_lock(&core_lock);
2443 adapter = idr_find(&i2c_adapter_idr, nr);
2447 if (try_module_get(adapter->owner))
2448 get_device(&adapter->dev);
2453 mutex_unlock(&core_lock);
2456 EXPORT_SYMBOL(i2c_get_adapter);
2458 void i2c_put_adapter(struct i2c_adapter *adap)
2463 put_device(&adap->dev);
2464 module_put(adap->owner);
2466 EXPORT_SYMBOL(i2c_put_adapter);
2469 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2470 * @msg: the message to be checked
2471 * @threshold: the minimum number of bytes for which using DMA makes sense.
2472 * Should at least be 1.
2474 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2475 * Or a valid pointer to be used with DMA. After use, release it by
2476 * calling i2c_put_dma_safe_msg_buf().
2478 * This function must only be called from process context!
2480 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2482 /* also skip 0-length msgs for bogus thresholds of 0 */
2484 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2486 if (msg->len < threshold || msg->len == 0)
2489 if (msg->flags & I2C_M_DMA_SAFE)
2492 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2493 msg->addr, msg->len);
2495 if (msg->flags & I2C_M_RD)
2496 return kzalloc(msg->len, GFP_KERNEL);
2498 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2500 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2503 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2504 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2505 * @msg: the message which the buffer corresponds to
2506 * @xferred: bool saying if the message was transferred
2508 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2510 if (!buf || buf == msg->buf)
2513 if (xferred && msg->flags & I2C_M_RD)
2514 memcpy(msg->buf, buf, msg->len);
2518 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2520 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2521 MODULE_DESCRIPTION("I2C-Bus main module");
2522 MODULE_LICENSE("GPL");