1 /* i2c-core.c - a device driver for the iic-bus interface */
2 /* ------------------------------------------------------------------------- */
3 /* Copyright (C) 1995-99 Simon G. Vogl
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details. */
14 /* ------------------------------------------------------------------------- */
16 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
17 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
18 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
19 Jean Delvare <jdelvare@suse.de>
20 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
21 Michael Lawnick <michael.lawnick.ext@nsn.com>
22 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
23 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
24 (c) 2013 Wolfram Sang <wsa@the-dreams.de>
25 I2C ACPI code Copyright (C) 2014 Intel Corp
26 Author: Lan Tianyu <tianyu.lan@intel.com>
27 I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com>
30 #include <linux/module.h>
31 #include <linux/kernel.h>
32 #include <linux/delay.h>
33 #include <linux/errno.h>
34 #include <linux/gpio.h>
35 #include <linux/slab.h>
36 #include <linux/i2c.h>
37 #include <linux/init.h>
38 #include <linux/idr.h>
39 #include <linux/mutex.h>
41 #include <linux/of_device.h>
42 #include <linux/of_irq.h>
43 #include <linux/clk/clk-conf.h>
44 #include <linux/completion.h>
45 #include <linux/hardirq.h>
46 #include <linux/irqflags.h>
47 #include <linux/rwsem.h>
48 #include <linux/pm_runtime.h>
49 #include <linux/pm_domain.h>
50 #include <linux/acpi.h>
51 #include <linux/jump_label.h>
52 #include <asm/uaccess.h>
53 #include <linux/err.h>
57 #define CREATE_TRACE_POINTS
58 #include <trace/events/i2c.h>
60 /* core_lock protects i2c_adapter_idr, and guarantees
61 that device detection, deletion of detected devices, and attach_adapter
62 calls are serialized */
63 static DEFINE_MUTEX(core_lock
);
64 static DEFINE_IDR(i2c_adapter_idr
);
66 static struct device_type i2c_client_type
;
67 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
);
69 static struct static_key i2c_trace_msg
= STATIC_KEY_INIT_FALSE
;
71 void i2c_transfer_trace_reg(void)
73 static_key_slow_inc(&i2c_trace_msg
);
76 void i2c_transfer_trace_unreg(void)
78 static_key_slow_dec(&i2c_trace_msg
);
81 #if defined(CONFIG_ACPI)
82 struct acpi_i2c_handler_data
{
83 struct acpi_connection_info info
;
84 struct i2c_adapter
*adapter
;
97 static int acpi_i2c_add_resource(struct acpi_resource
*ares
, void *data
)
99 struct i2c_board_info
*info
= data
;
101 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
102 struct acpi_resource_i2c_serialbus
*sb
;
104 sb
= &ares
->data
.i2c_serial_bus
;
105 if (!info
->addr
&& sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_I2C
) {
106 info
->addr
= sb
->slave_address
;
107 if (sb
->access_mode
== ACPI_I2C_10BIT_MODE
)
108 info
->flags
|= I2C_CLIENT_TEN
;
110 } else if (info
->irq
< 0) {
113 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
117 /* Tell the ACPI core to skip this resource */
121 static acpi_status
acpi_i2c_add_device(acpi_handle handle
, u32 level
,
122 void *data
, void **return_value
)
124 struct i2c_adapter
*adapter
= data
;
125 struct list_head resource_list
;
126 struct i2c_board_info info
;
127 struct acpi_device
*adev
;
130 if (acpi_bus_get_device(handle
, &adev
))
132 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
135 memset(&info
, 0, sizeof(info
));
136 info
.fwnode
= acpi_fwnode_handle(adev
);
139 INIT_LIST_HEAD(&resource_list
);
140 ret
= acpi_dev_get_resources(adev
, &resource_list
,
141 acpi_i2c_add_resource
, &info
);
142 acpi_dev_free_resource_list(&resource_list
);
144 if (ret
< 0 || !info
.addr
)
147 adev
->power
.flags
.ignore_parent
= true;
148 strlcpy(info
.type
, dev_name(&adev
->dev
), sizeof(info
.type
));
149 if (!i2c_new_device(adapter
, &info
)) {
150 adev
->power
.flags
.ignore_parent
= false;
151 dev_err(&adapter
->dev
,
152 "failed to add I2C device %s from ACPI\n",
153 dev_name(&adev
->dev
));
160 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
161 * @adap: pointer to adapter
163 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
164 * namespace. When a device is found it will be added to the Linux device
165 * model and bound to the corresponding ACPI handle.
167 static void acpi_i2c_register_devices(struct i2c_adapter
*adap
)
172 if (!adap
->dev
.parent
)
175 handle
= ACPI_HANDLE(adap
->dev
.parent
);
179 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
180 acpi_i2c_add_device
, NULL
,
182 if (ACPI_FAILURE(status
))
183 dev_warn(&adap
->dev
, "failed to enumerate I2C slaves\n");
186 #else /* CONFIG_ACPI */
187 static inline void acpi_i2c_register_devices(struct i2c_adapter
*adap
) { }
188 #endif /* CONFIG_ACPI */
190 #ifdef CONFIG_ACPI_I2C_OPREGION
191 static int acpi_gsb_i2c_read_bytes(struct i2c_client
*client
,
192 u8 cmd
, u8
*data
, u8 data_len
)
195 struct i2c_msg msgs
[2];
199 buffer
= kzalloc(data_len
, GFP_KERNEL
);
203 msgs
[0].addr
= client
->addr
;
204 msgs
[0].flags
= client
->flags
;
208 msgs
[1].addr
= client
->addr
;
209 msgs
[1].flags
= client
->flags
| I2C_M_RD
;
210 msgs
[1].len
= data_len
;
211 msgs
[1].buf
= buffer
;
213 ret
= i2c_transfer(client
->adapter
, msgs
, ARRAY_SIZE(msgs
));
215 dev_err(&client
->adapter
->dev
, "i2c read failed\n");
217 memcpy(data
, buffer
, data_len
);
223 static int acpi_gsb_i2c_write_bytes(struct i2c_client
*client
,
224 u8 cmd
, u8
*data
, u8 data_len
)
227 struct i2c_msg msgs
[1];
231 buffer
= kzalloc(data_len
+ 1, GFP_KERNEL
);
236 memcpy(buffer
+ 1, data
, data_len
);
238 msgs
[0].addr
= client
->addr
;
239 msgs
[0].flags
= client
->flags
;
240 msgs
[0].len
= data_len
+ 1;
241 msgs
[0].buf
= buffer
;
243 ret
= i2c_transfer(client
->adapter
, msgs
, ARRAY_SIZE(msgs
));
245 dev_err(&client
->adapter
->dev
, "i2c write failed\n");
252 acpi_i2c_space_handler(u32 function
, acpi_physical_address command
,
253 u32 bits
, u64
*value64
,
254 void *handler_context
, void *region_context
)
256 struct gsb_buffer
*gsb
= (struct gsb_buffer
*)value64
;
257 struct acpi_i2c_handler_data
*data
= handler_context
;
258 struct acpi_connection_info
*info
= &data
->info
;
259 struct acpi_resource_i2c_serialbus
*sb
;
260 struct i2c_adapter
*adapter
= data
->adapter
;
261 struct i2c_client client
;
262 struct acpi_resource
*ares
;
263 u32 accessor_type
= function
>> 16;
264 u8 action
= function
& ACPI_IO_MASK
;
268 ret
= acpi_buffer_to_resource(info
->connection
, info
->length
, &ares
);
269 if (ACPI_FAILURE(ret
))
272 if (!value64
|| ares
->type
!= ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
273 ret
= AE_BAD_PARAMETER
;
277 sb
= &ares
->data
.i2c_serial_bus
;
278 if (sb
->type
!= ACPI_RESOURCE_SERIAL_TYPE_I2C
) {
279 ret
= AE_BAD_PARAMETER
;
283 memset(&client
, 0, sizeof(client
));
284 client
.adapter
= adapter
;
285 client
.addr
= sb
->slave_address
;
288 if (sb
->access_mode
== ACPI_I2C_10BIT_MODE
)
289 client
.flags
|= I2C_CLIENT_TEN
;
291 switch (accessor_type
) {
292 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV
:
293 if (action
== ACPI_READ
) {
294 status
= i2c_smbus_read_byte(&client
);
300 status
= i2c_smbus_write_byte(&client
, gsb
->bdata
);
304 case ACPI_GSB_ACCESS_ATTRIB_BYTE
:
305 if (action
== ACPI_READ
) {
306 status
= i2c_smbus_read_byte_data(&client
, command
);
312 status
= i2c_smbus_write_byte_data(&client
, command
,
317 case ACPI_GSB_ACCESS_ATTRIB_WORD
:
318 if (action
== ACPI_READ
) {
319 status
= i2c_smbus_read_word_data(&client
, command
);
325 status
= i2c_smbus_write_word_data(&client
, command
,
330 case ACPI_GSB_ACCESS_ATTRIB_BLOCK
:
331 if (action
== ACPI_READ
) {
332 status
= i2c_smbus_read_block_data(&client
, command
,
339 status
= i2c_smbus_write_block_data(&client
, command
,
340 gsb
->len
, gsb
->data
);
344 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE
:
345 if (action
== ACPI_READ
) {
346 status
= acpi_gsb_i2c_read_bytes(&client
, command
,
347 gsb
->data
, info
->access_length
);
351 status
= acpi_gsb_i2c_write_bytes(&client
, command
,
352 gsb
->data
, info
->access_length
);
357 pr_info("protocol(0x%02x) is not supported.\n", accessor_type
);
358 ret
= AE_BAD_PARAMETER
;
362 gsb
->status
= status
;
370 static int acpi_i2c_install_space_handler(struct i2c_adapter
*adapter
)
373 struct acpi_i2c_handler_data
*data
;
376 if (!adapter
->dev
.parent
)
379 handle
= ACPI_HANDLE(adapter
->dev
.parent
);
384 data
= kzalloc(sizeof(struct acpi_i2c_handler_data
),
389 data
->adapter
= adapter
;
390 status
= acpi_bus_attach_private_data(handle
, (void *)data
);
391 if (ACPI_FAILURE(status
)) {
396 status
= acpi_install_address_space_handler(handle
,
397 ACPI_ADR_SPACE_GSBUS
,
398 &acpi_i2c_space_handler
,
401 if (ACPI_FAILURE(status
)) {
402 dev_err(&adapter
->dev
, "Error installing i2c space handler\n");
403 acpi_bus_detach_private_data(handle
);
408 acpi_walk_dep_device_list(handle
);
412 static void acpi_i2c_remove_space_handler(struct i2c_adapter
*adapter
)
415 struct acpi_i2c_handler_data
*data
;
418 if (!adapter
->dev
.parent
)
421 handle
= ACPI_HANDLE(adapter
->dev
.parent
);
426 acpi_remove_address_space_handler(handle
,
427 ACPI_ADR_SPACE_GSBUS
,
428 &acpi_i2c_space_handler
);
430 status
= acpi_bus_get_private_data(handle
, (void **)&data
);
431 if (ACPI_SUCCESS(status
))
434 acpi_bus_detach_private_data(handle
);
436 #else /* CONFIG_ACPI_I2C_OPREGION */
437 static inline void acpi_i2c_remove_space_handler(struct i2c_adapter
*adapter
)
440 static inline int acpi_i2c_install_space_handler(struct i2c_adapter
*adapter
)
442 #endif /* CONFIG_ACPI_I2C_OPREGION */
444 /* ------------------------------------------------------------------------- */
446 static const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
447 const struct i2c_client
*client
)
449 while (id
->name
[0]) {
450 if (strcmp(client
->name
, id
->name
) == 0)
457 static int i2c_device_match(struct device
*dev
, struct device_driver
*drv
)
459 struct i2c_client
*client
= i2c_verify_client(dev
);
460 struct i2c_driver
*driver
;
465 /* Attempt an OF style match */
466 if (of_driver_match_device(dev
, drv
))
469 /* Then ACPI style match */
470 if (acpi_driver_match_device(dev
, drv
))
473 driver
= to_i2c_driver(drv
);
474 /* match on an id table if there is one */
475 if (driver
->id_table
)
476 return i2c_match_id(driver
->id_table
, client
) != NULL
;
482 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
483 static int i2c_device_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
485 struct i2c_client
*client
= to_i2c_client(dev
);
488 rc
= acpi_device_uevent_modalias(dev
, env
);
492 if (add_uevent_var(env
, "MODALIAS=%s%s",
493 I2C_MODULE_PREFIX
, client
->name
))
495 dev_dbg(dev
, "uevent\n");
499 /* i2c bus recovery routines */
500 static int get_scl_gpio_value(struct i2c_adapter
*adap
)
502 return gpio_get_value(adap
->bus_recovery_info
->scl_gpio
);
505 static void set_scl_gpio_value(struct i2c_adapter
*adap
, int val
)
507 gpio_set_value(adap
->bus_recovery_info
->scl_gpio
, val
);
510 static int get_sda_gpio_value(struct i2c_adapter
*adap
)
512 return gpio_get_value(adap
->bus_recovery_info
->sda_gpio
);
515 static int i2c_get_gpios_for_recovery(struct i2c_adapter
*adap
)
517 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
518 struct device
*dev
= &adap
->dev
;
521 ret
= gpio_request_one(bri
->scl_gpio
, GPIOF_OPEN_DRAIN
|
522 GPIOF_OUT_INIT_HIGH
, "i2c-scl");
524 dev_warn(dev
, "Can't get SCL gpio: %d\n", bri
->scl_gpio
);
529 if (gpio_request_one(bri
->sda_gpio
, GPIOF_IN
, "i2c-sda")) {
530 /* work without SDA polling */
531 dev_warn(dev
, "Can't get SDA gpio: %d. Not using SDA polling\n",
540 static void i2c_put_gpios_for_recovery(struct i2c_adapter
*adap
)
542 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
545 gpio_free(bri
->sda_gpio
);
547 gpio_free(bri
->scl_gpio
);
551 * We are generating clock pulses. ndelay() determines durating of clk pulses.
552 * We will generate clock with rate 100 KHz and so duration of both clock levels
553 * is: delay in ns = (10^6 / 100) / 2
555 #define RECOVERY_NDELAY 5000
556 #define RECOVERY_CLK_CNT 9
558 static int i2c_generic_recovery(struct i2c_adapter
*adap
)
560 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
561 int i
= 0, val
= 1, ret
= 0;
563 if (bri
->prepare_recovery
)
564 bri
->prepare_recovery(adap
);
567 * By this time SCL is high, as we need to give 9 falling-rising edges
569 while (i
++ < RECOVERY_CLK_CNT
* 2) {
571 /* Break if SDA is high */
572 if (bri
->get_sda
&& bri
->get_sda(adap
))
574 /* SCL shouldn't be low here */
575 if (!bri
->get_scl(adap
)) {
577 "SCL is stuck low, exit recovery\n");
584 bri
->set_scl(adap
, val
);
585 ndelay(RECOVERY_NDELAY
);
588 if (bri
->unprepare_recovery
)
589 bri
->unprepare_recovery(adap
);
594 int i2c_generic_scl_recovery(struct i2c_adapter
*adap
)
596 adap
->bus_recovery_info
->set_scl(adap
, 1);
597 return i2c_generic_recovery(adap
);
600 int i2c_generic_gpio_recovery(struct i2c_adapter
*adap
)
604 ret
= i2c_get_gpios_for_recovery(adap
);
608 ret
= i2c_generic_recovery(adap
);
609 i2c_put_gpios_for_recovery(adap
);
614 int i2c_recover_bus(struct i2c_adapter
*adap
)
616 if (!adap
->bus_recovery_info
)
619 dev_dbg(&adap
->dev
, "Trying i2c bus recovery\n");
620 return adap
->bus_recovery_info
->recover_bus(adap
);
623 static int i2c_device_probe(struct device
*dev
)
625 struct i2c_client
*client
= i2c_verify_client(dev
);
626 struct i2c_driver
*driver
;
632 if (!client
->irq
&& dev
->of_node
) {
633 int irq
= of_irq_get(dev
->of_node
, 0);
635 if (irq
== -EPROBE_DEFER
)
643 driver
= to_i2c_driver(dev
->driver
);
644 if (!driver
->probe
|| !driver
->id_table
)
647 if (!device_can_wakeup(&client
->dev
))
648 device_init_wakeup(&client
->dev
,
649 client
->flags
& I2C_CLIENT_WAKE
);
650 dev_dbg(dev
, "probe\n");
652 status
= of_clk_set_defaults(dev
->of_node
, false);
656 status
= dev_pm_domain_attach(&client
->dev
, true);
657 if (status
!= -EPROBE_DEFER
) {
658 status
= driver
->probe(client
, i2c_match_id(driver
->id_table
,
661 dev_pm_domain_detach(&client
->dev
, true);
667 static int i2c_device_remove(struct device
*dev
)
669 struct i2c_client
*client
= i2c_verify_client(dev
);
670 struct i2c_driver
*driver
;
673 if (!client
|| !dev
->driver
)
676 driver
= to_i2c_driver(dev
->driver
);
677 if (driver
->remove
) {
678 dev_dbg(dev
, "remove\n");
679 status
= driver
->remove(client
);
682 dev_pm_domain_detach(&client
->dev
, true);
686 static void i2c_device_shutdown(struct device
*dev
)
688 struct i2c_client
*client
= i2c_verify_client(dev
);
689 struct i2c_driver
*driver
;
691 if (!client
|| !dev
->driver
)
693 driver
= to_i2c_driver(dev
->driver
);
694 if (driver
->shutdown
)
695 driver
->shutdown(client
);
698 static void i2c_client_dev_release(struct device
*dev
)
700 kfree(to_i2c_client(dev
));
704 show_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
706 return sprintf(buf
, "%s\n", dev
->type
== &i2c_client_type
?
707 to_i2c_client(dev
)->name
: to_i2c_adapter(dev
)->name
);
709 static DEVICE_ATTR(name
, S_IRUGO
, show_name
, NULL
);
712 show_modalias(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
714 struct i2c_client
*client
= to_i2c_client(dev
);
717 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
-1);
721 return sprintf(buf
, "%s%s\n", I2C_MODULE_PREFIX
, client
->name
);
723 static DEVICE_ATTR(modalias
, S_IRUGO
, show_modalias
, NULL
);
725 static struct attribute
*i2c_dev_attrs
[] = {
727 /* modalias helps coldplug: modprobe $(cat .../modalias) */
728 &dev_attr_modalias
.attr
,
731 ATTRIBUTE_GROUPS(i2c_dev
);
733 struct bus_type i2c_bus_type
= {
735 .match
= i2c_device_match
,
736 .probe
= i2c_device_probe
,
737 .remove
= i2c_device_remove
,
738 .shutdown
= i2c_device_shutdown
,
740 EXPORT_SYMBOL_GPL(i2c_bus_type
);
742 static struct device_type i2c_client_type
= {
743 .groups
= i2c_dev_groups
,
744 .uevent
= i2c_device_uevent
,
745 .release
= i2c_client_dev_release
,
750 * i2c_verify_client - return parameter as i2c_client, or NULL
751 * @dev: device, probably from some driver model iterator
753 * When traversing the driver model tree, perhaps using driver model
754 * iterators like @device_for_each_child(), you can't assume very much
755 * about the nodes you find. Use this function to avoid oopses caused
756 * by wrongly treating some non-I2C device as an i2c_client.
758 struct i2c_client
*i2c_verify_client(struct device
*dev
)
760 return (dev
->type
== &i2c_client_type
)
764 EXPORT_SYMBOL(i2c_verify_client
);
767 /* This is a permissive address validity check, I2C address map constraints
768 * are purposely not enforced, except for the general call address. */
769 static int i2c_check_client_addr_validity(const struct i2c_client
*client
)
771 if (client
->flags
& I2C_CLIENT_TEN
) {
772 /* 10-bit address, all values are valid */
773 if (client
->addr
> 0x3ff)
776 /* 7-bit address, reject the general call address */
777 if (client
->addr
== 0x00 || client
->addr
> 0x7f)
783 /* And this is a strict address validity check, used when probing. If a
784 * device uses a reserved address, then it shouldn't be probed. 7-bit
785 * addressing is assumed, 10-bit address devices are rare and should be
786 * explicitly enumerated. */
787 static int i2c_check_addr_validity(unsigned short addr
)
790 * Reserved addresses per I2C specification:
791 * 0x00 General call address / START byte
793 * 0x02 Reserved for different bus format
794 * 0x03 Reserved for future purposes
795 * 0x04-0x07 Hs-mode master code
796 * 0x78-0x7b 10-bit slave addressing
797 * 0x7c-0x7f Reserved for future purposes
799 if (addr
< 0x08 || addr
> 0x77)
804 static int __i2c_check_addr_busy(struct device
*dev
, void *addrp
)
806 struct i2c_client
*client
= i2c_verify_client(dev
);
807 int addr
= *(int *)addrp
;
809 if (client
&& client
->addr
== addr
)
814 /* walk up mux tree */
815 static int i2c_check_mux_parents(struct i2c_adapter
*adapter
, int addr
)
817 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
820 result
= device_for_each_child(&adapter
->dev
, &addr
,
821 __i2c_check_addr_busy
);
823 if (!result
&& parent
)
824 result
= i2c_check_mux_parents(parent
, addr
);
829 /* recurse down mux tree */
830 static int i2c_check_mux_children(struct device
*dev
, void *addrp
)
834 if (dev
->type
== &i2c_adapter_type
)
835 result
= device_for_each_child(dev
, addrp
,
836 i2c_check_mux_children
);
838 result
= __i2c_check_addr_busy(dev
, addrp
);
843 static int i2c_check_addr_busy(struct i2c_adapter
*adapter
, int addr
)
845 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
849 result
= i2c_check_mux_parents(parent
, addr
);
852 result
= device_for_each_child(&adapter
->dev
, &addr
,
853 i2c_check_mux_children
);
859 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
860 * @adapter: Target I2C bus segment
862 void i2c_lock_adapter(struct i2c_adapter
*adapter
)
864 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
867 i2c_lock_adapter(parent
);
869 rt_mutex_lock(&adapter
->bus_lock
);
871 EXPORT_SYMBOL_GPL(i2c_lock_adapter
);
874 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
875 * @adapter: Target I2C bus segment
877 static int i2c_trylock_adapter(struct i2c_adapter
*adapter
)
879 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
882 return i2c_trylock_adapter(parent
);
884 return rt_mutex_trylock(&adapter
->bus_lock
);
888 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
889 * @adapter: Target I2C bus segment
891 void i2c_unlock_adapter(struct i2c_adapter
*adapter
)
893 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
896 i2c_unlock_adapter(parent
);
898 rt_mutex_unlock(&adapter
->bus_lock
);
900 EXPORT_SYMBOL_GPL(i2c_unlock_adapter
);
902 static void i2c_dev_set_name(struct i2c_adapter
*adap
,
903 struct i2c_client
*client
)
905 struct acpi_device
*adev
= ACPI_COMPANION(&client
->dev
);
908 dev_set_name(&client
->dev
, "i2c-%s", acpi_dev_name(adev
));
912 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
913 dev_set_name(&client
->dev
, "%d-%04x", i2c_adapter_id(adap
),
914 client
->addr
| ((client
->flags
& I2C_CLIENT_TEN
)
919 * i2c_new_device - instantiate an i2c device
920 * @adap: the adapter managing the device
921 * @info: describes one I2C device; bus_num is ignored
924 * Create an i2c device. Binding is handled through driver model
925 * probe()/remove() methods. A driver may be bound to this device when we
926 * return from this function, or any later moment (e.g. maybe hotplugging will
927 * load the driver module). This call is not appropriate for use by mainboard
928 * initialization logic, which usually runs during an arch_initcall() long
929 * before any i2c_adapter could exist.
931 * This returns the new i2c client, which may be saved for later use with
932 * i2c_unregister_device(); or NULL to indicate an error.
935 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
)
937 struct i2c_client
*client
;
940 client
= kzalloc(sizeof *client
, GFP_KERNEL
);
944 client
->adapter
= adap
;
946 client
->dev
.platform_data
= info
->platform_data
;
949 client
->dev
.archdata
= *info
->archdata
;
951 client
->flags
= info
->flags
;
952 client
->addr
= info
->addr
;
953 client
->irq
= info
->irq
;
955 strlcpy(client
->name
, info
->type
, sizeof(client
->name
));
957 /* Check for address validity */
958 status
= i2c_check_client_addr_validity(client
);
960 dev_err(&adap
->dev
, "Invalid %d-bit I2C address 0x%02hx\n",
961 client
->flags
& I2C_CLIENT_TEN
? 10 : 7, client
->addr
);
965 /* Check for address business */
966 status
= i2c_check_addr_busy(adap
, client
->addr
);
970 client
->dev
.parent
= &client
->adapter
->dev
;
971 client
->dev
.bus
= &i2c_bus_type
;
972 client
->dev
.type
= &i2c_client_type
;
973 client
->dev
.of_node
= info
->of_node
;
974 client
->dev
.fwnode
= info
->fwnode
;
976 i2c_dev_set_name(adap
, client
);
977 status
= device_register(&client
->dev
);
981 dev_dbg(&adap
->dev
, "client [%s] registered with bus id %s\n",
982 client
->name
, dev_name(&client
->dev
));
987 dev_err(&adap
->dev
, "Failed to register i2c client %s at 0x%02x "
988 "(%d)\n", client
->name
, client
->addr
, status
);
993 EXPORT_SYMBOL_GPL(i2c_new_device
);
997 * i2c_unregister_device - reverse effect of i2c_new_device()
998 * @client: value returned from i2c_new_device()
1001 void i2c_unregister_device(struct i2c_client
*client
)
1003 device_unregister(&client
->dev
);
1005 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
1008 static const struct i2c_device_id dummy_id
[] = {
1013 static int dummy_probe(struct i2c_client
*client
,
1014 const struct i2c_device_id
*id
)
1019 static int dummy_remove(struct i2c_client
*client
)
1024 static struct i2c_driver dummy_driver
= {
1025 .driver
.name
= "dummy",
1026 .probe
= dummy_probe
,
1027 .remove
= dummy_remove
,
1028 .id_table
= dummy_id
,
1032 * i2c_new_dummy - return a new i2c device bound to a dummy driver
1033 * @adapter: the adapter managing the device
1034 * @address: seven bit address to be used
1035 * Context: can sleep
1037 * This returns an I2C client bound to the "dummy" driver, intended for use
1038 * with devices that consume multiple addresses. Examples of such chips
1039 * include various EEPROMS (like 24c04 and 24c08 models).
1041 * These dummy devices have two main uses. First, most I2C and SMBus calls
1042 * except i2c_transfer() need a client handle; the dummy will be that handle.
1043 * And second, this prevents the specified address from being bound to a
1046 * This returns the new i2c client, which should be saved for later use with
1047 * i2c_unregister_device(); or NULL to indicate an error.
1049 struct i2c_client
*i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
1051 struct i2c_board_info info
= {
1052 I2C_BOARD_INFO("dummy", address
),
1055 return i2c_new_device(adapter
, &info
);
1057 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
1059 /* ------------------------------------------------------------------------- */
1061 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1063 static void i2c_adapter_dev_release(struct device
*dev
)
1065 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1066 complete(&adap
->dev_released
);
1070 * This function is only needed for mutex_lock_nested, so it is never
1071 * called unless locking correctness checking is enabled. Thus we
1072 * make it inline to avoid a compiler warning. That's what gcc ends up
1075 static inline unsigned int i2c_adapter_depth(struct i2c_adapter
*adapter
)
1077 unsigned int depth
= 0;
1079 while ((adapter
= i2c_parent_is_i2c_adapter(adapter
)))
1086 * Let users instantiate I2C devices through sysfs. This can be used when
1087 * platform initialization code doesn't contain the proper data for
1088 * whatever reason. Also useful for drivers that do device detection and
1089 * detection fails, either because the device uses an unexpected address,
1090 * or this is a compatible device with different ID register values.
1092 * Parameter checking may look overzealous, but we really don't want
1093 * the user to provide incorrect parameters.
1096 i2c_sysfs_new_device(struct device
*dev
, struct device_attribute
*attr
,
1097 const char *buf
, size_t count
)
1099 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1100 struct i2c_board_info info
;
1101 struct i2c_client
*client
;
1105 memset(&info
, 0, sizeof(struct i2c_board_info
));
1107 blank
= strchr(buf
, ' ');
1109 dev_err(dev
, "%s: Missing parameters\n", "new_device");
1112 if (blank
- buf
> I2C_NAME_SIZE
- 1) {
1113 dev_err(dev
, "%s: Invalid device name\n", "new_device");
1116 memcpy(info
.type
, buf
, blank
- buf
);
1118 /* Parse remaining parameters, reject extra parameters */
1119 res
= sscanf(++blank
, "%hi%c", &info
.addr
, &end
);
1121 dev_err(dev
, "%s: Can't parse I2C address\n", "new_device");
1124 if (res
> 1 && end
!= '\n') {
1125 dev_err(dev
, "%s: Extra parameters\n", "new_device");
1129 client
= i2c_new_device(adap
, &info
);
1133 /* Keep track of the added device */
1134 mutex_lock(&adap
->userspace_clients_lock
);
1135 list_add_tail(&client
->detected
, &adap
->userspace_clients
);
1136 mutex_unlock(&adap
->userspace_clients_lock
);
1137 dev_info(dev
, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1138 info
.type
, info
.addr
);
1142 static DEVICE_ATTR(new_device
, S_IWUSR
, NULL
, i2c_sysfs_new_device
);
1145 * And of course let the users delete the devices they instantiated, if
1146 * they got it wrong. This interface can only be used to delete devices
1147 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1148 * don't delete devices to which some kernel code still has references.
1150 * Parameter checking may look overzealous, but we really don't want
1151 * the user to delete the wrong device.
1154 i2c_sysfs_delete_device(struct device
*dev
, struct device_attribute
*attr
,
1155 const char *buf
, size_t count
)
1157 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1158 struct i2c_client
*client
, *next
;
1159 unsigned short addr
;
1163 /* Parse parameters, reject extra parameters */
1164 res
= sscanf(buf
, "%hi%c", &addr
, &end
);
1166 dev_err(dev
, "%s: Can't parse I2C address\n", "delete_device");
1169 if (res
> 1 && end
!= '\n') {
1170 dev_err(dev
, "%s: Extra parameters\n", "delete_device");
1174 /* Make sure the device was added through sysfs */
1176 mutex_lock_nested(&adap
->userspace_clients_lock
,
1177 i2c_adapter_depth(adap
));
1178 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1180 if (client
->addr
== addr
) {
1181 dev_info(dev
, "%s: Deleting device %s at 0x%02hx\n",
1182 "delete_device", client
->name
, client
->addr
);
1184 list_del(&client
->detected
);
1185 i2c_unregister_device(client
);
1190 mutex_unlock(&adap
->userspace_clients_lock
);
1193 dev_err(dev
, "%s: Can't find device in list\n",
1197 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device
, S_IWUSR
, NULL
,
1198 i2c_sysfs_delete_device
);
1200 static struct attribute
*i2c_adapter_attrs
[] = {
1201 &dev_attr_name
.attr
,
1202 &dev_attr_new_device
.attr
,
1203 &dev_attr_delete_device
.attr
,
1206 ATTRIBUTE_GROUPS(i2c_adapter
);
1208 struct device_type i2c_adapter_type
= {
1209 .groups
= i2c_adapter_groups
,
1210 .release
= i2c_adapter_dev_release
,
1212 EXPORT_SYMBOL_GPL(i2c_adapter_type
);
1215 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1216 * @dev: device, probably from some driver model iterator
1218 * When traversing the driver model tree, perhaps using driver model
1219 * iterators like @device_for_each_child(), you can't assume very much
1220 * about the nodes you find. Use this function to avoid oopses caused
1221 * by wrongly treating some non-I2C device as an i2c_adapter.
1223 struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
)
1225 return (dev
->type
== &i2c_adapter_type
)
1226 ? to_i2c_adapter(dev
)
1229 EXPORT_SYMBOL(i2c_verify_adapter
);
1231 #ifdef CONFIG_I2C_COMPAT
1232 static struct class_compat
*i2c_adapter_compat_class
;
1235 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
1237 struct i2c_devinfo
*devinfo
;
1239 down_read(&__i2c_board_lock
);
1240 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
1241 if (devinfo
->busnum
== adapter
->nr
1242 && !i2c_new_device(adapter
,
1243 &devinfo
->board_info
))
1244 dev_err(&adapter
->dev
,
1245 "Can't create device at 0x%02x\n",
1246 devinfo
->board_info
.addr
);
1248 up_read(&__i2c_board_lock
);
1251 /* OF support code */
1253 #if IS_ENABLED(CONFIG_OF)
1254 static struct i2c_client
*of_i2c_register_device(struct i2c_adapter
*adap
,
1255 struct device_node
*node
)
1257 struct i2c_client
*result
;
1258 struct i2c_board_info info
= {};
1259 struct dev_archdata dev_ad
= {};
1263 dev_dbg(&adap
->dev
, "of_i2c: register %s\n", node
->full_name
);
1265 if (of_modalias_node(node
, info
.type
, sizeof(info
.type
)) < 0) {
1266 dev_err(&adap
->dev
, "of_i2c: modalias failure on %s\n",
1268 return ERR_PTR(-EINVAL
);
1271 addr
= of_get_property(node
, "reg", &len
);
1272 if (!addr
|| (len
< sizeof(int))) {
1273 dev_err(&adap
->dev
, "of_i2c: invalid reg on %s\n",
1275 return ERR_PTR(-EINVAL
);
1278 info
.addr
= be32_to_cpup(addr
);
1279 if (info
.addr
> (1 << 10) - 1) {
1280 dev_err(&adap
->dev
, "of_i2c: invalid addr=%x on %s\n",
1281 info
.addr
, node
->full_name
);
1282 return ERR_PTR(-EINVAL
);
1285 info
.of_node
= of_node_get(node
);
1286 info
.archdata
= &dev_ad
;
1288 if (of_get_property(node
, "wakeup-source", NULL
))
1289 info
.flags
|= I2C_CLIENT_WAKE
;
1291 result
= i2c_new_device(adap
, &info
);
1292 if (result
== NULL
) {
1293 dev_err(&adap
->dev
, "of_i2c: Failure registering %s\n",
1296 return ERR_PTR(-EINVAL
);
1301 static void of_i2c_register_devices(struct i2c_adapter
*adap
)
1303 struct device_node
*node
;
1305 /* Only register child devices if the adapter has a node pointer set */
1306 if (!adap
->dev
.of_node
)
1309 dev_dbg(&adap
->dev
, "of_i2c: walking child nodes\n");
1311 for_each_available_child_of_node(adap
->dev
.of_node
, node
)
1312 of_i2c_register_device(adap
, node
);
1315 static int of_dev_node_match(struct device
*dev
, void *data
)
1317 return dev
->of_node
== data
;
1320 /* must call put_device() when done with returned i2c_client device */
1321 struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
)
1325 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1330 return i2c_verify_client(dev
);
1332 EXPORT_SYMBOL(of_find_i2c_device_by_node
);
1334 /* must call put_device() when done with returned i2c_adapter device */
1335 struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
)
1339 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1344 return i2c_verify_adapter(dev
);
1346 EXPORT_SYMBOL(of_find_i2c_adapter_by_node
);
1348 static void of_i2c_register_devices(struct i2c_adapter
*adap
) { }
1349 #endif /* CONFIG_OF */
1351 static int i2c_do_add_adapter(struct i2c_driver
*driver
,
1352 struct i2c_adapter
*adap
)
1354 /* Detect supported devices on that bus, and instantiate them */
1355 i2c_detect(adap
, driver
);
1357 /* Let legacy drivers scan this bus for matching devices */
1358 if (driver
->attach_adapter
) {
1359 dev_warn(&adap
->dev
, "%s: attach_adapter method is deprecated\n",
1360 driver
->driver
.name
);
1361 dev_warn(&adap
->dev
, "Please use another way to instantiate "
1362 "your i2c_client\n");
1363 /* We ignore the return code; if it fails, too bad */
1364 driver
->attach_adapter(adap
);
1369 static int __process_new_adapter(struct device_driver
*d
, void *data
)
1371 return i2c_do_add_adapter(to_i2c_driver(d
), data
);
1374 static int i2c_register_adapter(struct i2c_adapter
*adap
)
1378 /* Can't register until after driver model init */
1379 if (unlikely(WARN_ON(!i2c_bus_type
.p
))) {
1385 if (unlikely(adap
->name
[0] == '\0')) {
1386 pr_err("i2c-core: Attempt to register an adapter with "
1390 if (unlikely(!adap
->algo
)) {
1391 pr_err("i2c-core: Attempt to register adapter '%s' with "
1392 "no algo!\n", adap
->name
);
1396 rt_mutex_init(&adap
->bus_lock
);
1397 mutex_init(&adap
->userspace_clients_lock
);
1398 INIT_LIST_HEAD(&adap
->userspace_clients
);
1400 /* Set default timeout to 1 second if not already set */
1401 if (adap
->timeout
== 0)
1404 dev_set_name(&adap
->dev
, "i2c-%d", adap
->nr
);
1405 adap
->dev
.bus
= &i2c_bus_type
;
1406 adap
->dev
.type
= &i2c_adapter_type
;
1407 res
= device_register(&adap
->dev
);
1411 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
1413 #ifdef CONFIG_I2C_COMPAT
1414 res
= class_compat_create_link(i2c_adapter_compat_class
, &adap
->dev
,
1417 dev_warn(&adap
->dev
,
1418 "Failed to create compatibility class link\n");
1421 /* bus recovery specific initialization */
1422 if (adap
->bus_recovery_info
) {
1423 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
1425 if (!bri
->recover_bus
) {
1426 dev_err(&adap
->dev
, "No recover_bus() found, not using recovery\n");
1427 adap
->bus_recovery_info
= NULL
;
1431 /* Generic GPIO recovery */
1432 if (bri
->recover_bus
== i2c_generic_gpio_recovery
) {
1433 if (!gpio_is_valid(bri
->scl_gpio
)) {
1434 dev_err(&adap
->dev
, "Invalid SCL gpio, not using recovery\n");
1435 adap
->bus_recovery_info
= NULL
;
1439 if (gpio_is_valid(bri
->sda_gpio
))
1440 bri
->get_sda
= get_sda_gpio_value
;
1442 bri
->get_sda
= NULL
;
1444 bri
->get_scl
= get_scl_gpio_value
;
1445 bri
->set_scl
= set_scl_gpio_value
;
1446 } else if (!bri
->set_scl
|| !bri
->get_scl
) {
1447 /* Generic SCL recovery */
1448 dev_err(&adap
->dev
, "No {get|set}_gpio() found, not using recovery\n");
1449 adap
->bus_recovery_info
= NULL
;
1454 /* create pre-declared device nodes */
1455 of_i2c_register_devices(adap
);
1456 acpi_i2c_register_devices(adap
);
1457 acpi_i2c_install_space_handler(adap
);
1459 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
1460 i2c_scan_static_board_info(adap
);
1462 /* Notify drivers */
1463 mutex_lock(&core_lock
);
1464 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
, __process_new_adapter
);
1465 mutex_unlock(&core_lock
);
1470 mutex_lock(&core_lock
);
1471 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1472 mutex_unlock(&core_lock
);
1477 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1478 * @adap: the adapter to register (with adap->nr initialized)
1479 * Context: can sleep
1481 * See i2c_add_numbered_adapter() for details.
1483 static int __i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1487 mutex_lock(&core_lock
);
1488 id
= idr_alloc(&i2c_adapter_idr
, adap
, adap
->nr
, adap
->nr
+ 1,
1490 mutex_unlock(&core_lock
);
1492 return id
== -ENOSPC
? -EBUSY
: id
;
1494 return i2c_register_adapter(adap
);
1498 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1499 * @adapter: the adapter to add
1500 * Context: can sleep
1502 * This routine is used to declare an I2C adapter when its bus number
1503 * doesn't matter or when its bus number is specified by an dt alias.
1504 * Examples of bases when the bus number doesn't matter: I2C adapters
1505 * dynamically added by USB links or PCI plugin cards.
1507 * When this returns zero, a new bus number was allocated and stored
1508 * in adap->nr, and the specified adapter became available for clients.
1509 * Otherwise, a negative errno value is returned.
1511 int i2c_add_adapter(struct i2c_adapter
*adapter
)
1513 struct device
*dev
= &adapter
->dev
;
1517 id
= of_alias_get_id(dev
->of_node
, "i2c");
1520 return __i2c_add_numbered_adapter(adapter
);
1524 mutex_lock(&core_lock
);
1525 id
= idr_alloc(&i2c_adapter_idr
, adapter
,
1526 __i2c_first_dynamic_bus_num
, 0, GFP_KERNEL
);
1527 mutex_unlock(&core_lock
);
1533 return i2c_register_adapter(adapter
);
1535 EXPORT_SYMBOL(i2c_add_adapter
);
1538 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1539 * @adap: the adapter to register (with adap->nr initialized)
1540 * Context: can sleep
1542 * This routine is used to declare an I2C adapter when its bus number
1543 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1544 * or otherwise built in to the system's mainboard, and where i2c_board_info
1545 * is used to properly configure I2C devices.
1547 * If the requested bus number is set to -1, then this function will behave
1548 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1550 * If no devices have pre-been declared for this bus, then be sure to
1551 * register the adapter before any dynamically allocated ones. Otherwise
1552 * the required bus ID may not be available.
1554 * When this returns zero, the specified adapter became available for
1555 * clients using the bus number provided in adap->nr. Also, the table
1556 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1557 * and the appropriate driver model device nodes are created. Otherwise, a
1558 * negative errno value is returned.
1560 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1562 if (adap
->nr
== -1) /* -1 means dynamically assign bus id */
1563 return i2c_add_adapter(adap
);
1565 return __i2c_add_numbered_adapter(adap
);
1567 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
1569 static void i2c_do_del_adapter(struct i2c_driver
*driver
,
1570 struct i2c_adapter
*adapter
)
1572 struct i2c_client
*client
, *_n
;
1574 /* Remove the devices we created ourselves as the result of hardware
1575 * probing (using a driver's detect method) */
1576 list_for_each_entry_safe(client
, _n
, &driver
->clients
, detected
) {
1577 if (client
->adapter
== adapter
) {
1578 dev_dbg(&adapter
->dev
, "Removing %s at 0x%x\n",
1579 client
->name
, client
->addr
);
1580 list_del(&client
->detected
);
1581 i2c_unregister_device(client
);
1586 static int __unregister_client(struct device
*dev
, void *dummy
)
1588 struct i2c_client
*client
= i2c_verify_client(dev
);
1589 if (client
&& strcmp(client
->name
, "dummy"))
1590 i2c_unregister_device(client
);
1594 static int __unregister_dummy(struct device
*dev
, void *dummy
)
1596 struct i2c_client
*client
= i2c_verify_client(dev
);
1598 i2c_unregister_device(client
);
1602 static int __process_removed_adapter(struct device_driver
*d
, void *data
)
1604 i2c_do_del_adapter(to_i2c_driver(d
), data
);
1609 * i2c_del_adapter - unregister I2C adapter
1610 * @adap: the adapter being unregistered
1611 * Context: can sleep
1613 * This unregisters an I2C adapter which was previously registered
1614 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1616 void i2c_del_adapter(struct i2c_adapter
*adap
)
1618 struct i2c_adapter
*found
;
1619 struct i2c_client
*client
, *next
;
1621 /* First make sure that this adapter was ever added */
1622 mutex_lock(&core_lock
);
1623 found
= idr_find(&i2c_adapter_idr
, adap
->nr
);
1624 mutex_unlock(&core_lock
);
1625 if (found
!= adap
) {
1626 pr_debug("i2c-core: attempting to delete unregistered "
1627 "adapter [%s]\n", adap
->name
);
1631 acpi_i2c_remove_space_handler(adap
);
1632 /* Tell drivers about this removal */
1633 mutex_lock(&core_lock
);
1634 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
1635 __process_removed_adapter
);
1636 mutex_unlock(&core_lock
);
1638 /* Remove devices instantiated from sysfs */
1639 mutex_lock_nested(&adap
->userspace_clients_lock
,
1640 i2c_adapter_depth(adap
));
1641 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1643 dev_dbg(&adap
->dev
, "Removing %s at 0x%x\n", client
->name
,
1645 list_del(&client
->detected
);
1646 i2c_unregister_device(client
);
1648 mutex_unlock(&adap
->userspace_clients_lock
);
1650 /* Detach any active clients. This can't fail, thus we do not
1651 * check the returned value. This is a two-pass process, because
1652 * we can't remove the dummy devices during the first pass: they
1653 * could have been instantiated by real devices wishing to clean
1654 * them up properly, so we give them a chance to do that first. */
1655 device_for_each_child(&adap
->dev
, NULL
, __unregister_client
);
1656 device_for_each_child(&adap
->dev
, NULL
, __unregister_dummy
);
1658 #ifdef CONFIG_I2C_COMPAT
1659 class_compat_remove_link(i2c_adapter_compat_class
, &adap
->dev
,
1663 /* device name is gone after device_unregister */
1664 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
1666 /* wait until all references to the device are gone
1668 * FIXME: This is old code and should ideally be replaced by an
1669 * alternative which results in decoupling the lifetime of the struct
1670 * device from the i2c_adapter, like spi or netdev do. Any solution
1671 * should be throughly tested with DEBUG_KOBJECT_RELEASE enabled!
1673 init_completion(&adap
->dev_released
);
1674 device_unregister(&adap
->dev
);
1675 wait_for_completion(&adap
->dev_released
);
1678 mutex_lock(&core_lock
);
1679 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1680 mutex_unlock(&core_lock
);
1682 /* Clear the device structure in case this adapter is ever going to be
1684 memset(&adap
->dev
, 0, sizeof(adap
->dev
));
1686 EXPORT_SYMBOL(i2c_del_adapter
);
1688 /* ------------------------------------------------------------------------- */
1690 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *))
1694 mutex_lock(&core_lock
);
1695 res
= bus_for_each_dev(&i2c_bus_type
, NULL
, data
, fn
);
1696 mutex_unlock(&core_lock
);
1700 EXPORT_SYMBOL_GPL(i2c_for_each_dev
);
1702 static int __process_new_driver(struct device
*dev
, void *data
)
1704 if (dev
->type
!= &i2c_adapter_type
)
1706 return i2c_do_add_adapter(data
, to_i2c_adapter(dev
));
1710 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1711 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1714 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
1718 /* Can't register until after driver model init */
1719 if (unlikely(WARN_ON(!i2c_bus_type
.p
)))
1722 /* add the driver to the list of i2c drivers in the driver core */
1723 driver
->driver
.owner
= owner
;
1724 driver
->driver
.bus
= &i2c_bus_type
;
1726 /* When registration returns, the driver core
1727 * will have called probe() for all matching-but-unbound devices.
1729 res
= driver_register(&driver
->driver
);
1733 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
1735 INIT_LIST_HEAD(&driver
->clients
);
1736 /* Walk the adapters that are already present */
1737 i2c_for_each_dev(driver
, __process_new_driver
);
1741 EXPORT_SYMBOL(i2c_register_driver
);
1743 static int __process_removed_driver(struct device
*dev
, void *data
)
1745 if (dev
->type
== &i2c_adapter_type
)
1746 i2c_do_del_adapter(data
, to_i2c_adapter(dev
));
1751 * i2c_del_driver - unregister I2C driver
1752 * @driver: the driver being unregistered
1753 * Context: can sleep
1755 void i2c_del_driver(struct i2c_driver
*driver
)
1757 i2c_for_each_dev(driver
, __process_removed_driver
);
1759 driver_unregister(&driver
->driver
);
1760 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
1762 EXPORT_SYMBOL(i2c_del_driver
);
1764 /* ------------------------------------------------------------------------- */
1767 * i2c_use_client - increments the reference count of the i2c client structure
1768 * @client: the client being referenced
1770 * Each live reference to a client should be refcounted. The driver model does
1771 * that automatically as part of driver binding, so that most drivers don't
1772 * need to do this explicitly: they hold a reference until they're unbound
1775 * A pointer to the client with the incremented reference counter is returned.
1777 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
1779 if (client
&& get_device(&client
->dev
))
1783 EXPORT_SYMBOL(i2c_use_client
);
1786 * i2c_release_client - release a use of the i2c client structure
1787 * @client: the client being no longer referenced
1789 * Must be called when a user of a client is finished with it.
1791 void i2c_release_client(struct i2c_client
*client
)
1794 put_device(&client
->dev
);
1796 EXPORT_SYMBOL(i2c_release_client
);
1798 struct i2c_cmd_arg
{
1803 static int i2c_cmd(struct device
*dev
, void *_arg
)
1805 struct i2c_client
*client
= i2c_verify_client(dev
);
1806 struct i2c_cmd_arg
*arg
= _arg
;
1807 struct i2c_driver
*driver
;
1809 if (!client
|| !client
->dev
.driver
)
1812 driver
= to_i2c_driver(client
->dev
.driver
);
1813 if (driver
->command
)
1814 driver
->command(client
, arg
->cmd
, arg
->arg
);
1818 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
1820 struct i2c_cmd_arg cmd_arg
;
1824 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
1826 EXPORT_SYMBOL(i2c_clients_command
);
1828 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
1829 static int of_i2c_notify(struct notifier_block
*nb
, unsigned long action
,
1832 struct of_reconfig_data
*rd
= arg
;
1833 struct i2c_adapter
*adap
;
1834 struct i2c_client
*client
;
1836 switch (of_reconfig_get_state_change(action
, rd
)) {
1837 case OF_RECONFIG_CHANGE_ADD
:
1838 adap
= of_find_i2c_adapter_by_node(rd
->dn
->parent
);
1840 return NOTIFY_OK
; /* not for us */
1842 client
= of_i2c_register_device(adap
, rd
->dn
);
1843 put_device(&adap
->dev
);
1845 if (IS_ERR(client
)) {
1846 pr_err("%s: failed to create for '%s'\n",
1847 __func__
, rd
->dn
->full_name
);
1848 return notifier_from_errno(PTR_ERR(client
));
1851 case OF_RECONFIG_CHANGE_REMOVE
:
1852 /* find our device by node */
1853 client
= of_find_i2c_device_by_node(rd
->dn
);
1855 return NOTIFY_OK
; /* no? not meant for us */
1857 /* unregister takes one ref away */
1858 i2c_unregister_device(client
);
1860 /* and put the reference of the find */
1861 put_device(&client
->dev
);
1867 static struct notifier_block i2c_of_notifier
= {
1868 .notifier_call
= of_i2c_notify
,
1871 extern struct notifier_block i2c_of_notifier
;
1872 #endif /* CONFIG_OF_DYNAMIC */
1874 static int __init
i2c_init(void)
1878 retval
= of_alias_get_highest_id("i2c");
1880 down_write(&__i2c_board_lock
);
1881 if (retval
>= __i2c_first_dynamic_bus_num
)
1882 __i2c_first_dynamic_bus_num
= retval
+ 1;
1883 up_write(&__i2c_board_lock
);
1885 retval
= bus_register(&i2c_bus_type
);
1888 #ifdef CONFIG_I2C_COMPAT
1889 i2c_adapter_compat_class
= class_compat_register("i2c-adapter");
1890 if (!i2c_adapter_compat_class
) {
1895 retval
= i2c_add_driver(&dummy_driver
);
1899 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
1900 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier
));
1905 #ifdef CONFIG_I2C_COMPAT
1906 class_compat_unregister(i2c_adapter_compat_class
);
1909 bus_unregister(&i2c_bus_type
);
1913 static void __exit
i2c_exit(void)
1915 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
1916 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier
));
1917 i2c_del_driver(&dummy_driver
);
1918 #ifdef CONFIG_I2C_COMPAT
1919 class_compat_unregister(i2c_adapter_compat_class
);
1921 bus_unregister(&i2c_bus_type
);
1922 tracepoint_synchronize_unregister();
1925 /* We must initialize early, because some subsystems register i2c drivers
1926 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1928 postcore_initcall(i2c_init
);
1929 module_exit(i2c_exit
);
1931 /* ----------------------------------------------------
1932 * the functional interface to the i2c busses.
1933 * ----------------------------------------------------
1936 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1937 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1939 static int i2c_quirk_error(struct i2c_adapter
*adap
, struct i2c_msg
*msg
, char *err_msg
)
1941 dev_err_ratelimited(&adap
->dev
, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1942 err_msg
, msg
->addr
, msg
->len
,
1943 msg
->flags
& I2C_M_RD
? "read" : "write");
1947 static int i2c_check_for_quirks(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1949 const struct i2c_adapter_quirks
*q
= adap
->quirks
;
1950 int max_num
= q
->max_num_msgs
, i
;
1951 bool do_len_check
= true;
1953 if (q
->flags
& I2C_AQ_COMB
) {
1956 /* special checks for combined messages */
1958 if (q
->flags
& I2C_AQ_COMB_WRITE_FIRST
&& msgs
[0].flags
& I2C_M_RD
)
1959 return i2c_quirk_error(adap
, &msgs
[0], "1st comb msg must be write");
1961 if (q
->flags
& I2C_AQ_COMB_READ_SECOND
&& !(msgs
[1].flags
& I2C_M_RD
))
1962 return i2c_quirk_error(adap
, &msgs
[1], "2nd comb msg must be read");
1964 if (q
->flags
& I2C_AQ_COMB_SAME_ADDR
&& msgs
[0].addr
!= msgs
[1].addr
)
1965 return i2c_quirk_error(adap
, &msgs
[0], "comb msg only to same addr");
1967 if (i2c_quirk_exceeded(msgs
[0].len
, q
->max_comb_1st_msg_len
))
1968 return i2c_quirk_error(adap
, &msgs
[0], "msg too long");
1970 if (i2c_quirk_exceeded(msgs
[1].len
, q
->max_comb_2nd_msg_len
))
1971 return i2c_quirk_error(adap
, &msgs
[1], "msg too long");
1973 do_len_check
= false;
1977 if (i2c_quirk_exceeded(num
, max_num
))
1978 return i2c_quirk_error(adap
, &msgs
[0], "too many messages");
1980 for (i
= 0; i
< num
; i
++) {
1981 u16 len
= msgs
[i
].len
;
1983 if (msgs
[i
].flags
& I2C_M_RD
) {
1984 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_read_len
))
1985 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
1987 if (do_len_check
&& i2c_quirk_exceeded(len
, q
->max_write_len
))
1988 return i2c_quirk_error(adap
, &msgs
[i
], "msg too long");
1996 * __i2c_transfer - unlocked flavor of i2c_transfer
1997 * @adap: Handle to I2C bus
1998 * @msgs: One or more messages to execute before STOP is issued to
1999 * terminate the operation; each message begins with a START.
2000 * @num: Number of messages to be executed.
2002 * Returns negative errno, else the number of messages executed.
2004 * Adapter lock must be held when calling this function. No debug logging
2005 * takes place. adap->algo->master_xfer existence isn't checked.
2007 int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2009 unsigned long orig_jiffies
;
2012 if (adap
->quirks
&& i2c_check_for_quirks(adap
, msgs
, num
))
2015 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2016 * enabled. This is an efficient way of keeping the for-loop from
2017 * being executed when not needed.
2019 if (static_key_false(&i2c_trace_msg
)) {
2021 for (i
= 0; i
< num
; i
++)
2022 if (msgs
[i
].flags
& I2C_M_RD
)
2023 trace_i2c_read(adap
, &msgs
[i
], i
);
2025 trace_i2c_write(adap
, &msgs
[i
], i
);
2028 /* Retry automatically on arbitration loss */
2029 orig_jiffies
= jiffies
;
2030 for (ret
= 0, try = 0; try <= adap
->retries
; try++) {
2031 ret
= adap
->algo
->master_xfer(adap
, msgs
, num
);
2034 if (time_after(jiffies
, orig_jiffies
+ adap
->timeout
))
2038 if (static_key_false(&i2c_trace_msg
)) {
2040 for (i
= 0; i
< ret
; i
++)
2041 if (msgs
[i
].flags
& I2C_M_RD
)
2042 trace_i2c_reply(adap
, &msgs
[i
], i
);
2043 trace_i2c_result(adap
, i
, ret
);
2048 EXPORT_SYMBOL(__i2c_transfer
);
2051 * i2c_transfer - execute a single or combined I2C message
2052 * @adap: Handle to I2C bus
2053 * @msgs: One or more messages to execute before STOP is issued to
2054 * terminate the operation; each message begins with a START.
2055 * @num: Number of messages to be executed.
2057 * Returns negative errno, else the number of messages executed.
2059 * Note that there is no requirement that each message be sent to
2060 * the same slave address, although that is the most common model.
2062 int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2066 /* REVISIT the fault reporting model here is weak:
2068 * - When we get an error after receiving N bytes from a slave,
2069 * there is no way to report "N".
2071 * - When we get a NAK after transmitting N bytes to a slave,
2072 * there is no way to report "N" ... or to let the master
2073 * continue executing the rest of this combined message, if
2074 * that's the appropriate response.
2076 * - When for example "num" is two and we successfully complete
2077 * the first message but get an error part way through the
2078 * second, it's unclear whether that should be reported as
2079 * one (discarding status on the second message) or errno
2080 * (discarding status on the first one).
2083 if (adap
->algo
->master_xfer
) {
2085 for (ret
= 0; ret
< num
; ret
++) {
2086 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
2087 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
2088 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
2089 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
2093 if (in_atomic() || irqs_disabled()) {
2094 ret
= i2c_trylock_adapter(adap
);
2096 /* I2C activity is ongoing. */
2099 i2c_lock_adapter(adap
);
2102 ret
= __i2c_transfer(adap
, msgs
, num
);
2103 i2c_unlock_adapter(adap
);
2107 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
2111 EXPORT_SYMBOL(i2c_transfer
);
2114 * i2c_master_send - issue a single I2C message in master transmit mode
2115 * @client: Handle to slave device
2116 * @buf: Data that will be written to the slave
2117 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2119 * Returns negative errno, or else the number of bytes written.
2121 int i2c_master_send(const struct i2c_client
*client
, const char *buf
, int count
)
2124 struct i2c_adapter
*adap
= client
->adapter
;
2127 msg
.addr
= client
->addr
;
2128 msg
.flags
= client
->flags
& I2C_M_TEN
;
2130 msg
.buf
= (char *)buf
;
2132 ret
= i2c_transfer(adap
, &msg
, 1);
2135 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2136 * transmitted, else error code.
2138 return (ret
== 1) ? count
: ret
;
2140 EXPORT_SYMBOL(i2c_master_send
);
2143 * i2c_master_recv - issue a single I2C message in master receive mode
2144 * @client: Handle to slave device
2145 * @buf: Where to store data read from slave
2146 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2148 * Returns negative errno, or else the number of bytes read.
2150 int i2c_master_recv(const struct i2c_client
*client
, char *buf
, int count
)
2152 struct i2c_adapter
*adap
= client
->adapter
;
2156 msg
.addr
= client
->addr
;
2157 msg
.flags
= client
->flags
& I2C_M_TEN
;
2158 msg
.flags
|= I2C_M_RD
;
2162 ret
= i2c_transfer(adap
, &msg
, 1);
2165 * If everything went ok (i.e. 1 msg received), return #bytes received,
2168 return (ret
== 1) ? count
: ret
;
2170 EXPORT_SYMBOL(i2c_master_recv
);
2172 /* ----------------------------------------------------
2173 * the i2c address scanning function
2174 * Will not work for 10-bit addresses!
2175 * ----------------------------------------------------
2179 * Legacy default probe function, mostly relevant for SMBus. The default
2180 * probe method is a quick write, but it is known to corrupt the 24RF08
2181 * EEPROMs due to a state machine bug, and could also irreversibly
2182 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2183 * we use a short byte read instead. Also, some bus drivers don't implement
2184 * quick write, so we fallback to a byte read in that case too.
2185 * On x86, there is another special case for FSC hardware monitoring chips,
2186 * which want regular byte reads (address 0x73.) Fortunately, these are the
2187 * only known chips using this I2C address on PC hardware.
2188 * Returns 1 if probe succeeded, 0 if not.
2190 static int i2c_default_probe(struct i2c_adapter
*adap
, unsigned short addr
)
2193 union i2c_smbus_data dummy
;
2196 if (addr
== 0x73 && (adap
->class & I2C_CLASS_HWMON
)
2197 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
2198 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2199 I2C_SMBUS_BYTE_DATA
, &dummy
);
2202 if (!((addr
& ~0x07) == 0x30 || (addr
& ~0x0f) == 0x50)
2203 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
))
2204 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_WRITE
, 0,
2205 I2C_SMBUS_QUICK
, NULL
);
2206 else if (i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
))
2207 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2208 I2C_SMBUS_BYTE
, &dummy
);
2210 dev_warn(&adap
->dev
, "No suitable probing method supported for address 0x%02X\n",
2218 static int i2c_detect_address(struct i2c_client
*temp_client
,
2219 struct i2c_driver
*driver
)
2221 struct i2c_board_info info
;
2222 struct i2c_adapter
*adapter
= temp_client
->adapter
;
2223 int addr
= temp_client
->addr
;
2226 /* Make sure the address is valid */
2227 err
= i2c_check_addr_validity(addr
);
2229 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
2234 /* Skip if already in use */
2235 if (i2c_check_addr_busy(adapter
, addr
))
2238 /* Make sure there is something at this address */
2239 if (!i2c_default_probe(adapter
, addr
))
2242 /* Finally call the custom detection function */
2243 memset(&info
, 0, sizeof(struct i2c_board_info
));
2245 err
= driver
->detect(temp_client
, &info
);
2247 /* -ENODEV is returned if the detection fails. We catch it
2248 here as this isn't an error. */
2249 return err
== -ENODEV
? 0 : err
;
2252 /* Consistency check */
2253 if (info
.type
[0] == '\0') {
2254 dev_err(&adapter
->dev
, "%s detection function provided "
2255 "no name for 0x%x\n", driver
->driver
.name
,
2258 struct i2c_client
*client
;
2260 /* Detection succeeded, instantiate the device */
2261 if (adapter
->class & I2C_CLASS_DEPRECATED
)
2262 dev_warn(&adapter
->dev
,
2263 "This adapter will soon drop class based instantiation of devices. "
2264 "Please make sure client 0x%02x gets instantiated by other means. "
2265 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2268 dev_dbg(&adapter
->dev
, "Creating %s at 0x%02x\n",
2269 info
.type
, info
.addr
);
2270 client
= i2c_new_device(adapter
, &info
);
2272 list_add_tail(&client
->detected
, &driver
->clients
);
2274 dev_err(&adapter
->dev
, "Failed creating %s at 0x%02x\n",
2275 info
.type
, info
.addr
);
2280 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
)
2282 const unsigned short *address_list
;
2283 struct i2c_client
*temp_client
;
2285 int adap_id
= i2c_adapter_id(adapter
);
2287 address_list
= driver
->address_list
;
2288 if (!driver
->detect
|| !address_list
)
2291 /* Warn that the adapter lost class based instantiation */
2292 if (adapter
->class == I2C_CLASS_DEPRECATED
) {
2293 dev_dbg(&adapter
->dev
,
2294 "This adapter dropped support for I2C classes and "
2295 "won't auto-detect %s devices anymore. If you need it, check "
2296 "'Documentation/i2c/instantiating-devices' for alternatives.\n",
2297 driver
->driver
.name
);
2301 /* Stop here if the classes do not match */
2302 if (!(adapter
->class & driver
->class))
2305 /* Set up a temporary client to help detect callback */
2306 temp_client
= kzalloc(sizeof(struct i2c_client
), GFP_KERNEL
);
2309 temp_client
->adapter
= adapter
;
2311 for (i
= 0; address_list
[i
] != I2C_CLIENT_END
; i
+= 1) {
2312 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
2313 "addr 0x%02x\n", adap_id
, address_list
[i
]);
2314 temp_client
->addr
= address_list
[i
];
2315 err
= i2c_detect_address(temp_client
, driver
);
2324 int i2c_probe_func_quick_read(struct i2c_adapter
*adap
, unsigned short addr
)
2326 return i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2327 I2C_SMBUS_QUICK
, NULL
) >= 0;
2329 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read
);
2332 i2c_new_probed_device(struct i2c_adapter
*adap
,
2333 struct i2c_board_info
*info
,
2334 unsigned short const *addr_list
,
2335 int (*probe
)(struct i2c_adapter
*, unsigned short addr
))
2340 probe
= i2c_default_probe
;
2342 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
2343 /* Check address validity */
2344 if (i2c_check_addr_validity(addr_list
[i
]) < 0) {
2345 dev_warn(&adap
->dev
, "Invalid 7-bit address "
2346 "0x%02x\n", addr_list
[i
]);
2350 /* Check address availability */
2351 if (i2c_check_addr_busy(adap
, addr_list
[i
])) {
2352 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
2353 "use, not probing\n", addr_list
[i
]);
2357 /* Test address responsiveness */
2358 if (probe(adap
, addr_list
[i
]))
2362 if (addr_list
[i
] == I2C_CLIENT_END
) {
2363 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
2367 info
->addr
= addr_list
[i
];
2368 return i2c_new_device(adap
, info
);
2370 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
2372 struct i2c_adapter
*i2c_get_adapter(int nr
)
2374 struct i2c_adapter
*adapter
;
2376 mutex_lock(&core_lock
);
2377 adapter
= idr_find(&i2c_adapter_idr
, nr
);
2378 if (adapter
&& !try_module_get(adapter
->owner
))
2381 mutex_unlock(&core_lock
);
2384 EXPORT_SYMBOL(i2c_get_adapter
);
2386 void i2c_put_adapter(struct i2c_adapter
*adap
)
2389 module_put(adap
->owner
);
2391 EXPORT_SYMBOL(i2c_put_adapter
);
2393 /* The SMBus parts */
2395 #define POLY (0x1070U << 3)
2396 static u8
crc8(u16 data
)
2400 for (i
= 0; i
< 8; i
++) {
2405 return (u8
)(data
>> 8);
2408 /* Incremental CRC8 over count bytes in the array pointed to by p */
2409 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
2413 for (i
= 0; i
< count
; i
++)
2414 crc
= crc8((crc
^ p
[i
]) << 8);
2418 /* Assume a 7-bit address, which is reasonable for SMBus */
2419 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
2421 /* The address will be sent first */
2422 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
2423 pec
= i2c_smbus_pec(pec
, &addr
, 1);
2425 /* The data buffer follows */
2426 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
2429 /* Used for write only transactions */
2430 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
2432 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
2436 /* Return <0 on CRC error
2437 If there was a write before this read (most cases) we need to take the
2438 partial CRC from the write part into account.
2439 Note that this function does modify the message (we need to decrease the
2440 message length to hide the CRC byte from the caller). */
2441 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
2443 u8 rpec
= msg
->buf
[--msg
->len
];
2444 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
2447 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2455 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2456 * @client: Handle to slave device
2458 * This executes the SMBus "receive byte" protocol, returning negative errno
2459 * else the byte received from the device.
2461 s32
i2c_smbus_read_byte(const struct i2c_client
*client
)
2463 union i2c_smbus_data data
;
2466 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2468 I2C_SMBUS_BYTE
, &data
);
2469 return (status
< 0) ? status
: data
.byte
;
2471 EXPORT_SYMBOL(i2c_smbus_read_byte
);
2474 * i2c_smbus_write_byte - SMBus "send byte" protocol
2475 * @client: Handle to slave device
2476 * @value: Byte to be sent
2478 * This executes the SMBus "send byte" protocol, returning negative errno
2479 * else zero on success.
2481 s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
)
2483 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2484 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
2486 EXPORT_SYMBOL(i2c_smbus_write_byte
);
2489 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2490 * @client: Handle to slave device
2491 * @command: Byte interpreted by slave
2493 * This executes the SMBus "read byte" protocol, returning negative errno
2494 * else a data byte received from the device.
2496 s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
, u8 command
)
2498 union i2c_smbus_data data
;
2501 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2502 I2C_SMBUS_READ
, command
,
2503 I2C_SMBUS_BYTE_DATA
, &data
);
2504 return (status
< 0) ? status
: data
.byte
;
2506 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
2509 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2510 * @client: Handle to slave device
2511 * @command: Byte interpreted by slave
2512 * @value: Byte being written
2514 * This executes the SMBus "write byte" protocol, returning negative errno
2515 * else zero on success.
2517 s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
, u8 command
,
2520 union i2c_smbus_data data
;
2522 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2523 I2C_SMBUS_WRITE
, command
,
2524 I2C_SMBUS_BYTE_DATA
, &data
);
2526 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
2529 * i2c_smbus_read_word_data - SMBus "read word" protocol
2530 * @client: Handle to slave device
2531 * @command: Byte interpreted by slave
2533 * This executes the SMBus "read word" protocol, returning negative errno
2534 * else a 16-bit unsigned "word" received from the device.
2536 s32
i2c_smbus_read_word_data(const struct i2c_client
*client
, u8 command
)
2538 union i2c_smbus_data data
;
2541 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2542 I2C_SMBUS_READ
, command
,
2543 I2C_SMBUS_WORD_DATA
, &data
);
2544 return (status
< 0) ? status
: data
.word
;
2546 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
2549 * i2c_smbus_write_word_data - SMBus "write word" protocol
2550 * @client: Handle to slave device
2551 * @command: Byte interpreted by slave
2552 * @value: 16-bit "word" being written
2554 * This executes the SMBus "write word" protocol, returning negative errno
2555 * else zero on success.
2557 s32
i2c_smbus_write_word_data(const struct i2c_client
*client
, u8 command
,
2560 union i2c_smbus_data data
;
2562 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2563 I2C_SMBUS_WRITE
, command
,
2564 I2C_SMBUS_WORD_DATA
, &data
);
2566 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
2569 * i2c_smbus_read_block_data - SMBus "block read" protocol
2570 * @client: Handle to slave device
2571 * @command: Byte interpreted by slave
2572 * @values: Byte array into which data will be read; big enough to hold
2573 * the data returned by the slave. SMBus allows at most 32 bytes.
2575 * This executes the SMBus "block read" protocol, returning negative errno
2576 * else the number of data bytes in the slave's response.
2578 * Note that using this function requires that the client's adapter support
2579 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2580 * support this; its emulation through I2C messaging relies on a specific
2581 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2583 s32
i2c_smbus_read_block_data(const struct i2c_client
*client
, u8 command
,
2586 union i2c_smbus_data data
;
2589 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2590 I2C_SMBUS_READ
, command
,
2591 I2C_SMBUS_BLOCK_DATA
, &data
);
2595 memcpy(values
, &data
.block
[1], data
.block
[0]);
2596 return data
.block
[0];
2598 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
2601 * i2c_smbus_write_block_data - SMBus "block write" protocol
2602 * @client: Handle to slave device
2603 * @command: Byte interpreted by slave
2604 * @length: Size of data block; SMBus allows at most 32 bytes
2605 * @values: Byte array which will be written.
2607 * This executes the SMBus "block write" protocol, returning negative errno
2608 * else zero on success.
2610 s32
i2c_smbus_write_block_data(const struct i2c_client
*client
, u8 command
,
2611 u8 length
, const u8
*values
)
2613 union i2c_smbus_data data
;
2615 if (length
> I2C_SMBUS_BLOCK_MAX
)
2616 length
= I2C_SMBUS_BLOCK_MAX
;
2617 data
.block
[0] = length
;
2618 memcpy(&data
.block
[1], values
, length
);
2619 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2620 I2C_SMBUS_WRITE
, command
,
2621 I2C_SMBUS_BLOCK_DATA
, &data
);
2623 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
2625 /* Returns the number of read bytes */
2626 s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2627 u8 length
, u8
*values
)
2629 union i2c_smbus_data data
;
2632 if (length
> I2C_SMBUS_BLOCK_MAX
)
2633 length
= I2C_SMBUS_BLOCK_MAX
;
2634 data
.block
[0] = length
;
2635 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2636 I2C_SMBUS_READ
, command
,
2637 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2641 memcpy(values
, &data
.block
[1], data
.block
[0]);
2642 return data
.block
[0];
2644 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
2646 s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2647 u8 length
, const u8
*values
)
2649 union i2c_smbus_data data
;
2651 if (length
> I2C_SMBUS_BLOCK_MAX
)
2652 length
= I2C_SMBUS_BLOCK_MAX
;
2653 data
.block
[0] = length
;
2654 memcpy(data
.block
+ 1, values
, length
);
2655 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2656 I2C_SMBUS_WRITE
, command
,
2657 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2659 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
2661 /* Simulate a SMBus command using the i2c protocol
2662 No checking of parameters is done! */
2663 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
*adapter
, u16 addr
,
2664 unsigned short flags
,
2665 char read_write
, u8 command
, int size
,
2666 union i2c_smbus_data
*data
)
2668 /* So we need to generate a series of msgs. In the case of writing, we
2669 need to use only one message; when reading, we need two. We initialize
2670 most things with sane defaults, to keep the code below somewhat
2672 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
2673 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
2674 int num
= read_write
== I2C_SMBUS_READ
? 2 : 1;
2678 struct i2c_msg msg
[2] = {
2686 .flags
= flags
| I2C_M_RD
,
2692 msgbuf0
[0] = command
;
2694 case I2C_SMBUS_QUICK
:
2696 /* Special case: The read/write field is used as data */
2697 msg
[0].flags
= flags
| (read_write
== I2C_SMBUS_READ
?
2701 case I2C_SMBUS_BYTE
:
2702 if (read_write
== I2C_SMBUS_READ
) {
2703 /* Special case: only a read! */
2704 msg
[0].flags
= I2C_M_RD
| flags
;
2708 case I2C_SMBUS_BYTE_DATA
:
2709 if (read_write
== I2C_SMBUS_READ
)
2713 msgbuf0
[1] = data
->byte
;
2716 case I2C_SMBUS_WORD_DATA
:
2717 if (read_write
== I2C_SMBUS_READ
)
2721 msgbuf0
[1] = data
->word
& 0xff;
2722 msgbuf0
[2] = data
->word
>> 8;
2725 case I2C_SMBUS_PROC_CALL
:
2726 num
= 2; /* Special case */
2727 read_write
= I2C_SMBUS_READ
;
2730 msgbuf0
[1] = data
->word
& 0xff;
2731 msgbuf0
[2] = data
->word
>> 8;
2733 case I2C_SMBUS_BLOCK_DATA
:
2734 if (read_write
== I2C_SMBUS_READ
) {
2735 msg
[1].flags
|= I2C_M_RECV_LEN
;
2736 msg
[1].len
= 1; /* block length will be added by
2737 the underlying bus driver */
2739 msg
[0].len
= data
->block
[0] + 2;
2740 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
2741 dev_err(&adapter
->dev
,
2742 "Invalid block write size %d\n",
2746 for (i
= 1; i
< msg
[0].len
; i
++)
2747 msgbuf0
[i
] = data
->block
[i
-1];
2750 case I2C_SMBUS_BLOCK_PROC_CALL
:
2751 num
= 2; /* Another special case */
2752 read_write
= I2C_SMBUS_READ
;
2753 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
2754 dev_err(&adapter
->dev
,
2755 "Invalid block write size %d\n",
2759 msg
[0].len
= data
->block
[0] + 2;
2760 for (i
= 1; i
< msg
[0].len
; i
++)
2761 msgbuf0
[i
] = data
->block
[i
-1];
2762 msg
[1].flags
|= I2C_M_RECV_LEN
;
2763 msg
[1].len
= 1; /* block length will be added by
2764 the underlying bus driver */
2766 case I2C_SMBUS_I2C_BLOCK_DATA
:
2767 if (read_write
== I2C_SMBUS_READ
) {
2768 msg
[1].len
= data
->block
[0];
2770 msg
[0].len
= data
->block
[0] + 1;
2771 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
2772 dev_err(&adapter
->dev
,
2773 "Invalid block write size %d\n",
2777 for (i
= 1; i
<= data
->block
[0]; i
++)
2778 msgbuf0
[i
] = data
->block
[i
];
2782 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
2786 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
2787 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
2789 /* Compute PEC if first message is a write */
2790 if (!(msg
[0].flags
& I2C_M_RD
)) {
2791 if (num
== 1) /* Write only */
2792 i2c_smbus_add_pec(&msg
[0]);
2793 else /* Write followed by read */
2794 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
2796 /* Ask for PEC if last message is a read */
2797 if (msg
[num
-1].flags
& I2C_M_RD
)
2801 status
= i2c_transfer(adapter
, msg
, num
);
2805 /* Check PEC if last message is a read */
2806 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
2807 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
2812 if (read_write
== I2C_SMBUS_READ
)
2814 case I2C_SMBUS_BYTE
:
2815 data
->byte
= msgbuf0
[0];
2817 case I2C_SMBUS_BYTE_DATA
:
2818 data
->byte
= msgbuf1
[0];
2820 case I2C_SMBUS_WORD_DATA
:
2821 case I2C_SMBUS_PROC_CALL
:
2822 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
2824 case I2C_SMBUS_I2C_BLOCK_DATA
:
2825 for (i
= 0; i
< data
->block
[0]; i
++)
2826 data
->block
[i
+1] = msgbuf1
[i
];
2828 case I2C_SMBUS_BLOCK_DATA
:
2829 case I2C_SMBUS_BLOCK_PROC_CALL
:
2830 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
2831 data
->block
[i
] = msgbuf1
[i
];
2838 * i2c_smbus_xfer - execute SMBus protocol operations
2839 * @adapter: Handle to I2C bus
2840 * @addr: Address of SMBus slave on that bus
2841 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2842 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2843 * @command: Byte interpreted by slave, for protocols which use such bytes
2844 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2845 * @data: Data to be read or written
2847 * This executes an SMBus protocol operation, and returns a negative
2848 * errno code else zero on success.
2850 s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
, unsigned short flags
,
2851 char read_write
, u8 command
, int protocol
,
2852 union i2c_smbus_data
*data
)
2854 unsigned long orig_jiffies
;
2858 /* If enabled, the following two tracepoints are conditional on
2859 * read_write and protocol.
2861 trace_smbus_write(adapter
, addr
, flags
, read_write
,
2862 command
, protocol
, data
);
2863 trace_smbus_read(adapter
, addr
, flags
, read_write
,
2866 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
| I2C_CLIENT_SCCB
;
2868 if (adapter
->algo
->smbus_xfer
) {
2869 i2c_lock_adapter(adapter
);
2871 /* Retry automatically on arbitration loss */
2872 orig_jiffies
= jiffies
;
2873 for (res
= 0, try = 0; try <= adapter
->retries
; try++) {
2874 res
= adapter
->algo
->smbus_xfer(adapter
, addr
, flags
,
2875 read_write
, command
,
2879 if (time_after(jiffies
,
2880 orig_jiffies
+ adapter
->timeout
))
2883 i2c_unlock_adapter(adapter
);
2885 if (res
!= -EOPNOTSUPP
|| !adapter
->algo
->master_xfer
)
2888 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2889 * implement native support for the SMBus operation.
2893 res
= i2c_smbus_xfer_emulated(adapter
, addr
, flags
, read_write
,
2894 command
, protocol
, data
);
2897 /* If enabled, the reply tracepoint is conditional on read_write. */
2898 trace_smbus_reply(adapter
, addr
, flags
, read_write
,
2899 command
, protocol
, data
);
2900 trace_smbus_result(adapter
, addr
, flags
, read_write
,
2901 command
, protocol
, res
);
2905 EXPORT_SYMBOL(i2c_smbus_xfer
);
2907 #if IS_ENABLED(CONFIG_I2C_SLAVE)
2908 int i2c_slave_register(struct i2c_client
*client
, i2c_slave_cb_t slave_cb
)
2912 if (!client
|| !slave_cb
)
2915 if (!(client
->flags
& I2C_CLIENT_TEN
)) {
2916 /* Enforce stricter address checking */
2917 ret
= i2c_check_addr_validity(client
->addr
);
2922 if (!client
->adapter
->algo
->reg_slave
)
2925 client
->slave_cb
= slave_cb
;
2927 i2c_lock_adapter(client
->adapter
);
2928 ret
= client
->adapter
->algo
->reg_slave(client
);
2929 i2c_unlock_adapter(client
->adapter
);
2932 client
->slave_cb
= NULL
;
2936 EXPORT_SYMBOL_GPL(i2c_slave_register
);
2938 int i2c_slave_unregister(struct i2c_client
*client
)
2942 if (!client
->adapter
->algo
->unreg_slave
)
2945 i2c_lock_adapter(client
->adapter
);
2946 ret
= client
->adapter
->algo
->unreg_slave(client
);
2947 i2c_unlock_adapter(client
->adapter
);
2950 client
->slave_cb
= NULL
;
2954 EXPORT_SYMBOL_GPL(i2c_slave_unregister
);
2957 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2958 MODULE_DESCRIPTION("I2C-Bus main module");
2959 MODULE_LICENSE("GPL");