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>
29 #include <linux/module.h>
30 #include <linux/kernel.h>
31 #include <linux/delay.h>
32 #include <linux/errno.h>
33 #include <linux/gpio.h>
34 #include <linux/slab.h>
35 #include <linux/i2c.h>
36 #include <linux/init.h>
37 #include <linux/idr.h>
38 #include <linux/mutex.h>
40 #include <linux/of_device.h>
41 #include <linux/of_irq.h>
42 #include <linux/clk/clk-conf.h>
43 #include <linux/completion.h>
44 #include <linux/hardirq.h>
45 #include <linux/irqflags.h>
46 #include <linux/rwsem.h>
47 #include <linux/pm_runtime.h>
48 #include <linux/pm_domain.h>
49 #include <linux/acpi.h>
50 #include <linux/jump_label.h>
51 #include <asm/uaccess.h>
52 #include <linux/err.h>
56 #define CREATE_TRACE_POINTS
57 #include <trace/events/i2c.h>
59 /* core_lock protects i2c_adapter_idr, and guarantees
60 that device detection, deletion of detected devices, and attach_adapter
61 calls are serialized */
62 static DEFINE_MUTEX(core_lock
);
63 static DEFINE_IDR(i2c_adapter_idr
);
65 static struct device_type i2c_client_type
;
66 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
);
68 static struct static_key i2c_trace_msg
= STATIC_KEY_INIT_FALSE
;
70 void i2c_transfer_trace_reg(void)
72 static_key_slow_inc(&i2c_trace_msg
);
75 void i2c_transfer_trace_unreg(void)
77 static_key_slow_dec(&i2c_trace_msg
);
80 #if defined(CONFIG_ACPI)
81 struct acpi_i2c_handler_data
{
82 struct acpi_connection_info info
;
83 struct i2c_adapter
*adapter
;
96 static int acpi_i2c_add_resource(struct acpi_resource
*ares
, void *data
)
98 struct i2c_board_info
*info
= data
;
100 if (ares
->type
== ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
101 struct acpi_resource_i2c_serialbus
*sb
;
103 sb
= &ares
->data
.i2c_serial_bus
;
104 if (sb
->type
== ACPI_RESOURCE_SERIAL_TYPE_I2C
) {
105 info
->addr
= sb
->slave_address
;
106 if (sb
->access_mode
== ACPI_I2C_10BIT_MODE
)
107 info
->flags
|= I2C_CLIENT_TEN
;
109 } else if (info
->irq
< 0) {
112 if (acpi_dev_resource_interrupt(ares
, 0, &r
))
116 /* Tell the ACPI core to skip this resource */
120 static acpi_status
acpi_i2c_add_device(acpi_handle handle
, u32 level
,
121 void *data
, void **return_value
)
123 struct i2c_adapter
*adapter
= data
;
124 struct list_head resource_list
;
125 struct i2c_board_info info
;
126 struct acpi_device
*adev
;
129 if (acpi_bus_get_device(handle
, &adev
))
131 if (acpi_bus_get_status(adev
) || !adev
->status
.present
)
134 memset(&info
, 0, sizeof(info
));
135 info
.acpi_node
.companion
= adev
;
138 INIT_LIST_HEAD(&resource_list
);
139 ret
= acpi_dev_get_resources(adev
, &resource_list
,
140 acpi_i2c_add_resource
, &info
);
141 acpi_dev_free_resource_list(&resource_list
);
143 if (ret
< 0 || !info
.addr
)
146 adev
->power
.flags
.ignore_parent
= true;
147 strlcpy(info
.type
, dev_name(&adev
->dev
), sizeof(info
.type
));
148 if (!i2c_new_device(adapter
, &info
)) {
149 adev
->power
.flags
.ignore_parent
= false;
150 dev_err(&adapter
->dev
,
151 "failed to add I2C device %s from ACPI\n",
152 dev_name(&adev
->dev
));
159 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
160 * @adap: pointer to adapter
162 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
163 * namespace. When a device is found it will be added to the Linux device
164 * model and bound to the corresponding ACPI handle.
166 static void acpi_i2c_register_devices(struct i2c_adapter
*adap
)
171 if (!adap
->dev
.parent
)
174 handle
= ACPI_HANDLE(adap
->dev
.parent
);
178 status
= acpi_walk_namespace(ACPI_TYPE_DEVICE
, handle
, 1,
179 acpi_i2c_add_device
, NULL
,
181 if (ACPI_FAILURE(status
))
182 dev_warn(&adap
->dev
, "failed to enumerate I2C slaves\n");
185 #else /* CONFIG_ACPI */
186 static inline void acpi_i2c_register_devices(struct i2c_adapter
*adap
) { }
187 #endif /* CONFIG_ACPI */
189 #ifdef CONFIG_ACPI_I2C_OPREGION
190 static int acpi_gsb_i2c_read_bytes(struct i2c_client
*client
,
191 u8 cmd
, u8
*data
, u8 data_len
)
194 struct i2c_msg msgs
[2];
198 buffer
= kzalloc(data_len
, GFP_KERNEL
);
202 msgs
[0].addr
= client
->addr
;
203 msgs
[0].flags
= client
->flags
;
207 msgs
[1].addr
= client
->addr
;
208 msgs
[1].flags
= client
->flags
| I2C_M_RD
;
209 msgs
[1].len
= data_len
;
210 msgs
[1].buf
= buffer
;
212 ret
= i2c_transfer(client
->adapter
, msgs
, ARRAY_SIZE(msgs
));
214 dev_err(&client
->adapter
->dev
, "i2c read failed\n");
216 memcpy(data
, buffer
, data_len
);
222 static int acpi_gsb_i2c_write_bytes(struct i2c_client
*client
,
223 u8 cmd
, u8
*data
, u8 data_len
)
226 struct i2c_msg msgs
[1];
230 buffer
= kzalloc(data_len
+ 1, GFP_KERNEL
);
235 memcpy(buffer
+ 1, data
, data_len
);
237 msgs
[0].addr
= client
->addr
;
238 msgs
[0].flags
= client
->flags
;
239 msgs
[0].len
= data_len
+ 1;
240 msgs
[0].buf
= buffer
;
242 ret
= i2c_transfer(client
->adapter
, msgs
, ARRAY_SIZE(msgs
));
244 dev_err(&client
->adapter
->dev
, "i2c write failed\n");
251 acpi_i2c_space_handler(u32 function
, acpi_physical_address command
,
252 u32 bits
, u64
*value64
,
253 void *handler_context
, void *region_context
)
255 struct gsb_buffer
*gsb
= (struct gsb_buffer
*)value64
;
256 struct acpi_i2c_handler_data
*data
= handler_context
;
257 struct acpi_connection_info
*info
= &data
->info
;
258 struct acpi_resource_i2c_serialbus
*sb
;
259 struct i2c_adapter
*adapter
= data
->adapter
;
260 struct i2c_client client
;
261 struct acpi_resource
*ares
;
262 u32 accessor_type
= function
>> 16;
263 u8 action
= function
& ACPI_IO_MASK
;
264 acpi_status ret
= AE_OK
;
267 ret
= acpi_buffer_to_resource(info
->connection
, info
->length
, &ares
);
268 if (ACPI_FAILURE(ret
))
271 if (!value64
|| ares
->type
!= ACPI_RESOURCE_TYPE_SERIAL_BUS
) {
272 ret
= AE_BAD_PARAMETER
;
276 sb
= &ares
->data
.i2c_serial_bus
;
277 if (sb
->type
!= ACPI_RESOURCE_SERIAL_TYPE_I2C
) {
278 ret
= AE_BAD_PARAMETER
;
282 memset(&client
, 0, sizeof(client
));
283 client
.adapter
= adapter
;
284 client
.addr
= sb
->slave_address
;
287 if (sb
->access_mode
== ACPI_I2C_10BIT_MODE
)
288 client
.flags
|= I2C_CLIENT_TEN
;
290 switch (accessor_type
) {
291 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV
:
292 if (action
== ACPI_READ
) {
293 status
= i2c_smbus_read_byte(&client
);
299 status
= i2c_smbus_write_byte(&client
, gsb
->bdata
);
303 case ACPI_GSB_ACCESS_ATTRIB_BYTE
:
304 if (action
== ACPI_READ
) {
305 status
= i2c_smbus_read_byte_data(&client
, command
);
311 status
= i2c_smbus_write_byte_data(&client
, command
,
316 case ACPI_GSB_ACCESS_ATTRIB_WORD
:
317 if (action
== ACPI_READ
) {
318 status
= i2c_smbus_read_word_data(&client
, command
);
324 status
= i2c_smbus_write_word_data(&client
, command
,
329 case ACPI_GSB_ACCESS_ATTRIB_BLOCK
:
330 if (action
== ACPI_READ
) {
331 status
= i2c_smbus_read_block_data(&client
, command
,
338 status
= i2c_smbus_write_block_data(&client
, command
,
339 gsb
->len
, gsb
->data
);
343 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE
:
344 if (action
== ACPI_READ
) {
345 status
= acpi_gsb_i2c_read_bytes(&client
, command
,
346 gsb
->data
, info
->access_length
);
350 status
= acpi_gsb_i2c_write_bytes(&client
, command
,
351 gsb
->data
, info
->access_length
);
356 pr_info("protocol(0x%02x) is not supported.\n", accessor_type
);
357 ret
= AE_BAD_PARAMETER
;
361 gsb
->status
= status
;
369 static int acpi_i2c_install_space_handler(struct i2c_adapter
*adapter
)
372 struct acpi_i2c_handler_data
*data
;
375 if (!adapter
->dev
.parent
)
378 handle
= ACPI_HANDLE(adapter
->dev
.parent
);
383 data
= kzalloc(sizeof(struct acpi_i2c_handler_data
),
388 data
->adapter
= adapter
;
389 status
= acpi_bus_attach_private_data(handle
, (void *)data
);
390 if (ACPI_FAILURE(status
)) {
395 status
= acpi_install_address_space_handler(handle
,
396 ACPI_ADR_SPACE_GSBUS
,
397 &acpi_i2c_space_handler
,
400 if (ACPI_FAILURE(status
)) {
401 dev_err(&adapter
->dev
, "Error installing i2c space handler\n");
402 acpi_bus_detach_private_data(handle
);
410 static void acpi_i2c_remove_space_handler(struct i2c_adapter
*adapter
)
413 struct acpi_i2c_handler_data
*data
;
416 if (!adapter
->dev
.parent
)
419 handle
= ACPI_HANDLE(adapter
->dev
.parent
);
424 acpi_remove_address_space_handler(handle
,
425 ACPI_ADR_SPACE_GSBUS
,
426 &acpi_i2c_space_handler
);
428 status
= acpi_bus_get_private_data(handle
, (void **)&data
);
429 if (ACPI_SUCCESS(status
))
432 acpi_bus_detach_private_data(handle
);
434 #else /* CONFIG_ACPI_I2C_OPREGION */
435 static inline void acpi_i2c_remove_space_handler(struct i2c_adapter
*adapter
)
438 static inline int acpi_i2c_install_space_handler(struct i2c_adapter
*adapter
)
440 #endif /* CONFIG_ACPI_I2C_OPREGION */
442 /* ------------------------------------------------------------------------- */
444 static const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
445 const struct i2c_client
*client
)
447 while (id
->name
[0]) {
448 if (strcmp(client
->name
, id
->name
) == 0)
455 static int i2c_device_match(struct device
*dev
, struct device_driver
*drv
)
457 struct i2c_client
*client
= i2c_verify_client(dev
);
458 struct i2c_driver
*driver
;
463 /* Attempt an OF style match */
464 if (of_driver_match_device(dev
, drv
))
467 /* Then ACPI style match */
468 if (acpi_driver_match_device(dev
, drv
))
471 driver
= to_i2c_driver(drv
);
472 /* match on an id table if there is one */
473 if (driver
->id_table
)
474 return i2c_match_id(driver
->id_table
, client
) != NULL
;
480 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
481 static int i2c_device_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
483 struct i2c_client
*client
= to_i2c_client(dev
);
486 rc
= acpi_device_uevent_modalias(dev
, env
);
490 if (add_uevent_var(env
, "MODALIAS=%s%s",
491 I2C_MODULE_PREFIX
, client
->name
))
493 dev_dbg(dev
, "uevent\n");
497 /* i2c bus recovery routines */
498 static int get_scl_gpio_value(struct i2c_adapter
*adap
)
500 return gpio_get_value(adap
->bus_recovery_info
->scl_gpio
);
503 static void set_scl_gpio_value(struct i2c_adapter
*adap
, int val
)
505 gpio_set_value(adap
->bus_recovery_info
->scl_gpio
, val
);
508 static int get_sda_gpio_value(struct i2c_adapter
*adap
)
510 return gpio_get_value(adap
->bus_recovery_info
->sda_gpio
);
513 static int i2c_get_gpios_for_recovery(struct i2c_adapter
*adap
)
515 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
516 struct device
*dev
= &adap
->dev
;
519 ret
= gpio_request_one(bri
->scl_gpio
, GPIOF_OPEN_DRAIN
|
520 GPIOF_OUT_INIT_HIGH
, "i2c-scl");
522 dev_warn(dev
, "Can't get SCL gpio: %d\n", bri
->scl_gpio
);
527 if (gpio_request_one(bri
->sda_gpio
, GPIOF_IN
, "i2c-sda")) {
528 /* work without SDA polling */
529 dev_warn(dev
, "Can't get SDA gpio: %d. Not using SDA polling\n",
538 static void i2c_put_gpios_for_recovery(struct i2c_adapter
*adap
)
540 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
543 gpio_free(bri
->sda_gpio
);
545 gpio_free(bri
->scl_gpio
);
549 * We are generating clock pulses. ndelay() determines durating of clk pulses.
550 * We will generate clock with rate 100 KHz and so duration of both clock levels
551 * is: delay in ns = (10^6 / 100) / 2
553 #define RECOVERY_NDELAY 5000
554 #define RECOVERY_CLK_CNT 9
556 static int i2c_generic_recovery(struct i2c_adapter
*adap
)
558 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
559 int i
= 0, val
= 1, ret
= 0;
561 if (bri
->prepare_recovery
)
562 bri
->prepare_recovery(bri
);
565 * By this time SCL is high, as we need to give 9 falling-rising edges
567 while (i
++ < RECOVERY_CLK_CNT
* 2) {
569 /* Break if SDA is high */
570 if (bri
->get_sda
&& bri
->get_sda(adap
))
572 /* SCL shouldn't be low here */
573 if (!bri
->get_scl(adap
)) {
575 "SCL is stuck low, exit recovery\n");
582 bri
->set_scl(adap
, val
);
583 ndelay(RECOVERY_NDELAY
);
586 if (bri
->unprepare_recovery
)
587 bri
->unprepare_recovery(bri
);
592 int i2c_generic_scl_recovery(struct i2c_adapter
*adap
)
594 adap
->bus_recovery_info
->set_scl(adap
, 1);
595 return i2c_generic_recovery(adap
);
598 int i2c_generic_gpio_recovery(struct i2c_adapter
*adap
)
602 ret
= i2c_get_gpios_for_recovery(adap
);
606 ret
= i2c_generic_recovery(adap
);
607 i2c_put_gpios_for_recovery(adap
);
612 int i2c_recover_bus(struct i2c_adapter
*adap
)
614 if (!adap
->bus_recovery_info
)
617 dev_dbg(&adap
->dev
, "Trying i2c bus recovery\n");
618 return adap
->bus_recovery_info
->recover_bus(adap
);
621 static int i2c_device_probe(struct device
*dev
)
623 struct i2c_client
*client
= i2c_verify_client(dev
);
624 struct i2c_driver
*driver
;
630 driver
= to_i2c_driver(dev
->driver
);
631 if (!driver
->probe
|| !driver
->id_table
)
634 if (!device_can_wakeup(&client
->dev
))
635 device_init_wakeup(&client
->dev
,
636 client
->flags
& I2C_CLIENT_WAKE
);
637 dev_dbg(dev
, "probe\n");
639 status
= of_clk_set_defaults(dev
->of_node
, false);
643 status
= dev_pm_domain_attach(&client
->dev
, true);
644 if (status
!= -EPROBE_DEFER
) {
645 status
= driver
->probe(client
, i2c_match_id(driver
->id_table
,
648 dev_pm_domain_detach(&client
->dev
, true);
654 static int i2c_device_remove(struct device
*dev
)
656 struct i2c_client
*client
= i2c_verify_client(dev
);
657 struct i2c_driver
*driver
;
660 if (!client
|| !dev
->driver
)
663 driver
= to_i2c_driver(dev
->driver
);
664 if (driver
->remove
) {
665 dev_dbg(dev
, "remove\n");
666 status
= driver
->remove(client
);
670 irq_dispose_mapping(client
->irq
);
672 dev_pm_domain_detach(&client
->dev
, true);
676 static void i2c_device_shutdown(struct device
*dev
)
678 struct i2c_client
*client
= i2c_verify_client(dev
);
679 struct i2c_driver
*driver
;
681 if (!client
|| !dev
->driver
)
683 driver
= to_i2c_driver(dev
->driver
);
684 if (driver
->shutdown
)
685 driver
->shutdown(client
);
688 #ifdef CONFIG_PM_SLEEP
689 static int i2c_legacy_suspend(struct device
*dev
, pm_message_t mesg
)
691 struct i2c_client
*client
= i2c_verify_client(dev
);
692 struct i2c_driver
*driver
;
694 if (!client
|| !dev
->driver
)
696 driver
= to_i2c_driver(dev
->driver
);
697 if (!driver
->suspend
)
699 return driver
->suspend(client
, mesg
);
702 static int i2c_legacy_resume(struct device
*dev
)
704 struct i2c_client
*client
= i2c_verify_client(dev
);
705 struct i2c_driver
*driver
;
707 if (!client
|| !dev
->driver
)
709 driver
= to_i2c_driver(dev
->driver
);
712 return driver
->resume(client
);
715 static int i2c_device_pm_suspend(struct device
*dev
)
717 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
720 return pm_generic_suspend(dev
);
722 return i2c_legacy_suspend(dev
, PMSG_SUSPEND
);
725 static int i2c_device_pm_resume(struct device
*dev
)
727 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
730 return pm_generic_resume(dev
);
732 return i2c_legacy_resume(dev
);
735 static int i2c_device_pm_freeze(struct device
*dev
)
737 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
740 return pm_generic_freeze(dev
);
742 return i2c_legacy_suspend(dev
, PMSG_FREEZE
);
745 static int i2c_device_pm_thaw(struct device
*dev
)
747 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
750 return pm_generic_thaw(dev
);
752 return i2c_legacy_resume(dev
);
755 static int i2c_device_pm_poweroff(struct device
*dev
)
757 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
760 return pm_generic_poweroff(dev
);
762 return i2c_legacy_suspend(dev
, PMSG_HIBERNATE
);
765 static int i2c_device_pm_restore(struct device
*dev
)
767 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
770 return pm_generic_restore(dev
);
772 return i2c_legacy_resume(dev
);
774 #else /* !CONFIG_PM_SLEEP */
775 #define i2c_device_pm_suspend NULL
776 #define i2c_device_pm_resume NULL
777 #define i2c_device_pm_freeze NULL
778 #define i2c_device_pm_thaw NULL
779 #define i2c_device_pm_poweroff NULL
780 #define i2c_device_pm_restore NULL
781 #endif /* !CONFIG_PM_SLEEP */
783 static void i2c_client_dev_release(struct device
*dev
)
785 kfree(to_i2c_client(dev
));
789 show_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
791 return sprintf(buf
, "%s\n", dev
->type
== &i2c_client_type
?
792 to_i2c_client(dev
)->name
: to_i2c_adapter(dev
)->name
);
796 show_modalias(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
798 struct i2c_client
*client
= to_i2c_client(dev
);
801 len
= acpi_device_modalias(dev
, buf
, PAGE_SIZE
-1);
805 return sprintf(buf
, "%s%s\n", I2C_MODULE_PREFIX
, client
->name
);
808 static DEVICE_ATTR(name
, S_IRUGO
, show_name
, NULL
);
809 static DEVICE_ATTR(modalias
, S_IRUGO
, show_modalias
, NULL
);
811 static struct attribute
*i2c_dev_attrs
[] = {
813 /* modalias helps coldplug: modprobe $(cat .../modalias) */
814 &dev_attr_modalias
.attr
,
818 static struct attribute_group i2c_dev_attr_group
= {
819 .attrs
= i2c_dev_attrs
,
822 static const struct attribute_group
*i2c_dev_attr_groups
[] = {
827 static const struct dev_pm_ops i2c_device_pm_ops
= {
828 .suspend
= i2c_device_pm_suspend
,
829 .resume
= i2c_device_pm_resume
,
830 .freeze
= i2c_device_pm_freeze
,
831 .thaw
= i2c_device_pm_thaw
,
832 .poweroff
= i2c_device_pm_poweroff
,
833 .restore
= i2c_device_pm_restore
,
835 pm_generic_runtime_suspend
,
836 pm_generic_runtime_resume
,
841 struct bus_type i2c_bus_type
= {
843 .match
= i2c_device_match
,
844 .probe
= i2c_device_probe
,
845 .remove
= i2c_device_remove
,
846 .shutdown
= i2c_device_shutdown
,
847 .pm
= &i2c_device_pm_ops
,
849 EXPORT_SYMBOL_GPL(i2c_bus_type
);
851 static struct device_type i2c_client_type
= {
852 .groups
= i2c_dev_attr_groups
,
853 .uevent
= i2c_device_uevent
,
854 .release
= i2c_client_dev_release
,
859 * i2c_verify_client - return parameter as i2c_client, or NULL
860 * @dev: device, probably from some driver model iterator
862 * When traversing the driver model tree, perhaps using driver model
863 * iterators like @device_for_each_child(), you can't assume very much
864 * about the nodes you find. Use this function to avoid oopses caused
865 * by wrongly treating some non-I2C device as an i2c_client.
867 struct i2c_client
*i2c_verify_client(struct device
*dev
)
869 return (dev
->type
== &i2c_client_type
)
873 EXPORT_SYMBOL(i2c_verify_client
);
876 /* This is a permissive address validity check, I2C address map constraints
877 * are purposely not enforced, except for the general call address. */
878 static int i2c_check_client_addr_validity(const struct i2c_client
*client
)
880 if (client
->flags
& I2C_CLIENT_TEN
) {
881 /* 10-bit address, all values are valid */
882 if (client
->addr
> 0x3ff)
885 /* 7-bit address, reject the general call address */
886 if (client
->addr
== 0x00 || client
->addr
> 0x7f)
892 /* And this is a strict address validity check, used when probing. If a
893 * device uses a reserved address, then it shouldn't be probed. 7-bit
894 * addressing is assumed, 10-bit address devices are rare and should be
895 * explicitly enumerated. */
896 static int i2c_check_addr_validity(unsigned short addr
)
899 * Reserved addresses per I2C specification:
900 * 0x00 General call address / START byte
902 * 0x02 Reserved for different bus format
903 * 0x03 Reserved for future purposes
904 * 0x04-0x07 Hs-mode master code
905 * 0x78-0x7b 10-bit slave addressing
906 * 0x7c-0x7f Reserved for future purposes
908 if (addr
< 0x08 || addr
> 0x77)
913 static int __i2c_check_addr_busy(struct device
*dev
, void *addrp
)
915 struct i2c_client
*client
= i2c_verify_client(dev
);
916 int addr
= *(int *)addrp
;
918 if (client
&& client
->addr
== addr
)
923 /* walk up mux tree */
924 static int i2c_check_mux_parents(struct i2c_adapter
*adapter
, int addr
)
926 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
929 result
= device_for_each_child(&adapter
->dev
, &addr
,
930 __i2c_check_addr_busy
);
932 if (!result
&& parent
)
933 result
= i2c_check_mux_parents(parent
, addr
);
938 /* recurse down mux tree */
939 static int i2c_check_mux_children(struct device
*dev
, void *addrp
)
943 if (dev
->type
== &i2c_adapter_type
)
944 result
= device_for_each_child(dev
, addrp
,
945 i2c_check_mux_children
);
947 result
= __i2c_check_addr_busy(dev
, addrp
);
952 static int i2c_check_addr_busy(struct i2c_adapter
*adapter
, int addr
)
954 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
958 result
= i2c_check_mux_parents(parent
, addr
);
961 result
= device_for_each_child(&adapter
->dev
, &addr
,
962 i2c_check_mux_children
);
968 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
969 * @adapter: Target I2C bus segment
971 void i2c_lock_adapter(struct i2c_adapter
*adapter
)
973 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
976 i2c_lock_adapter(parent
);
978 rt_mutex_lock(&adapter
->bus_lock
);
980 EXPORT_SYMBOL_GPL(i2c_lock_adapter
);
983 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
984 * @adapter: Target I2C bus segment
986 static int i2c_trylock_adapter(struct i2c_adapter
*adapter
)
988 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
991 return i2c_trylock_adapter(parent
);
993 return rt_mutex_trylock(&adapter
->bus_lock
);
997 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
998 * @adapter: Target I2C bus segment
1000 void i2c_unlock_adapter(struct i2c_adapter
*adapter
)
1002 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
1005 i2c_unlock_adapter(parent
);
1007 rt_mutex_unlock(&adapter
->bus_lock
);
1009 EXPORT_SYMBOL_GPL(i2c_unlock_adapter
);
1011 static void i2c_dev_set_name(struct i2c_adapter
*adap
,
1012 struct i2c_client
*client
)
1014 struct acpi_device
*adev
= ACPI_COMPANION(&client
->dev
);
1017 dev_set_name(&client
->dev
, "i2c-%s", acpi_dev_name(adev
));
1021 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
1022 dev_set_name(&client
->dev
, "%d-%04x", i2c_adapter_id(adap
),
1023 client
->addr
| ((client
->flags
& I2C_CLIENT_TEN
)
1028 * i2c_new_device - instantiate an i2c device
1029 * @adap: the adapter managing the device
1030 * @info: describes one I2C device; bus_num is ignored
1031 * Context: can sleep
1033 * Create an i2c device. Binding is handled through driver model
1034 * probe()/remove() methods. A driver may be bound to this device when we
1035 * return from this function, or any later moment (e.g. maybe hotplugging will
1036 * load the driver module). This call is not appropriate for use by mainboard
1037 * initialization logic, which usually runs during an arch_initcall() long
1038 * before any i2c_adapter could exist.
1040 * This returns the new i2c client, which may be saved for later use with
1041 * i2c_unregister_device(); or NULL to indicate an error.
1044 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
)
1046 struct i2c_client
*client
;
1049 client
= kzalloc(sizeof *client
, GFP_KERNEL
);
1053 client
->adapter
= adap
;
1055 client
->dev
.platform_data
= info
->platform_data
;
1058 client
->dev
.archdata
= *info
->archdata
;
1060 client
->flags
= info
->flags
;
1061 client
->addr
= info
->addr
;
1062 client
->irq
= info
->irq
;
1064 strlcpy(client
->name
, info
->type
, sizeof(client
->name
));
1066 /* Check for address validity */
1067 status
= i2c_check_client_addr_validity(client
);
1069 dev_err(&adap
->dev
, "Invalid %d-bit I2C address 0x%02hx\n",
1070 client
->flags
& I2C_CLIENT_TEN
? 10 : 7, client
->addr
);
1071 goto out_err_silent
;
1074 /* Check for address business */
1075 status
= i2c_check_addr_busy(adap
, client
->addr
);
1079 client
->dev
.parent
= &client
->adapter
->dev
;
1080 client
->dev
.bus
= &i2c_bus_type
;
1081 client
->dev
.type
= &i2c_client_type
;
1082 client
->dev
.of_node
= info
->of_node
;
1083 ACPI_COMPANION_SET(&client
->dev
, info
->acpi_node
.companion
);
1085 i2c_dev_set_name(adap
, client
);
1086 status
= device_register(&client
->dev
);
1090 dev_dbg(&adap
->dev
, "client [%s] registered with bus id %s\n",
1091 client
->name
, dev_name(&client
->dev
));
1096 dev_err(&adap
->dev
, "Failed to register i2c client %s at 0x%02x "
1097 "(%d)\n", client
->name
, client
->addr
, status
);
1102 EXPORT_SYMBOL_GPL(i2c_new_device
);
1106 * i2c_unregister_device - reverse effect of i2c_new_device()
1107 * @client: value returned from i2c_new_device()
1108 * Context: can sleep
1110 void i2c_unregister_device(struct i2c_client
*client
)
1112 device_unregister(&client
->dev
);
1114 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
1117 static const struct i2c_device_id dummy_id
[] = {
1122 static int dummy_probe(struct i2c_client
*client
,
1123 const struct i2c_device_id
*id
)
1128 static int dummy_remove(struct i2c_client
*client
)
1133 static struct i2c_driver dummy_driver
= {
1134 .driver
.name
= "dummy",
1135 .probe
= dummy_probe
,
1136 .remove
= dummy_remove
,
1137 .id_table
= dummy_id
,
1141 * i2c_new_dummy - return a new i2c device bound to a dummy driver
1142 * @adapter: the adapter managing the device
1143 * @address: seven bit address to be used
1144 * Context: can sleep
1146 * This returns an I2C client bound to the "dummy" driver, intended for use
1147 * with devices that consume multiple addresses. Examples of such chips
1148 * include various EEPROMS (like 24c04 and 24c08 models).
1150 * These dummy devices have two main uses. First, most I2C and SMBus calls
1151 * except i2c_transfer() need a client handle; the dummy will be that handle.
1152 * And second, this prevents the specified address from being bound to a
1155 * This returns the new i2c client, which should be saved for later use with
1156 * i2c_unregister_device(); or NULL to indicate an error.
1158 struct i2c_client
*i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
1160 struct i2c_board_info info
= {
1161 I2C_BOARD_INFO("dummy", address
),
1164 return i2c_new_device(adapter
, &info
);
1166 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
1168 /* ------------------------------------------------------------------------- */
1170 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1172 static void i2c_adapter_dev_release(struct device
*dev
)
1174 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1175 complete(&adap
->dev_released
);
1179 * This function is only needed for mutex_lock_nested, so it is never
1180 * called unless locking correctness checking is enabled. Thus we
1181 * make it inline to avoid a compiler warning. That's what gcc ends up
1184 static inline unsigned int i2c_adapter_depth(struct i2c_adapter
*adapter
)
1186 unsigned int depth
= 0;
1188 while ((adapter
= i2c_parent_is_i2c_adapter(adapter
)))
1195 * Let users instantiate I2C devices through sysfs. This can be used when
1196 * platform initialization code doesn't contain the proper data for
1197 * whatever reason. Also useful for drivers that do device detection and
1198 * detection fails, either because the device uses an unexpected address,
1199 * or this is a compatible device with different ID register values.
1201 * Parameter checking may look overzealous, but we really don't want
1202 * the user to provide incorrect parameters.
1205 i2c_sysfs_new_device(struct device
*dev
, struct device_attribute
*attr
,
1206 const char *buf
, size_t count
)
1208 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1209 struct i2c_board_info info
;
1210 struct i2c_client
*client
;
1214 memset(&info
, 0, sizeof(struct i2c_board_info
));
1216 blank
= strchr(buf
, ' ');
1218 dev_err(dev
, "%s: Missing parameters\n", "new_device");
1221 if (blank
- buf
> I2C_NAME_SIZE
- 1) {
1222 dev_err(dev
, "%s: Invalid device name\n", "new_device");
1225 memcpy(info
.type
, buf
, blank
- buf
);
1227 /* Parse remaining parameters, reject extra parameters */
1228 res
= sscanf(++blank
, "%hi%c", &info
.addr
, &end
);
1230 dev_err(dev
, "%s: Can't parse I2C address\n", "new_device");
1233 if (res
> 1 && end
!= '\n') {
1234 dev_err(dev
, "%s: Extra parameters\n", "new_device");
1238 client
= i2c_new_device(adap
, &info
);
1242 /* Keep track of the added device */
1243 mutex_lock(&adap
->userspace_clients_lock
);
1244 list_add_tail(&client
->detected
, &adap
->userspace_clients
);
1245 mutex_unlock(&adap
->userspace_clients_lock
);
1246 dev_info(dev
, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1247 info
.type
, info
.addr
);
1253 * And of course let the users delete the devices they instantiated, if
1254 * they got it wrong. This interface can only be used to delete devices
1255 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1256 * don't delete devices to which some kernel code still has references.
1258 * Parameter checking may look overzealous, but we really don't want
1259 * the user to delete the wrong device.
1262 i2c_sysfs_delete_device(struct device
*dev
, struct device_attribute
*attr
,
1263 const char *buf
, size_t count
)
1265 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
1266 struct i2c_client
*client
, *next
;
1267 unsigned short addr
;
1271 /* Parse parameters, reject extra parameters */
1272 res
= sscanf(buf
, "%hi%c", &addr
, &end
);
1274 dev_err(dev
, "%s: Can't parse I2C address\n", "delete_device");
1277 if (res
> 1 && end
!= '\n') {
1278 dev_err(dev
, "%s: Extra parameters\n", "delete_device");
1282 /* Make sure the device was added through sysfs */
1284 mutex_lock_nested(&adap
->userspace_clients_lock
,
1285 i2c_adapter_depth(adap
));
1286 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1288 if (client
->addr
== addr
) {
1289 dev_info(dev
, "%s: Deleting device %s at 0x%02hx\n",
1290 "delete_device", client
->name
, client
->addr
);
1292 list_del(&client
->detected
);
1293 i2c_unregister_device(client
);
1298 mutex_unlock(&adap
->userspace_clients_lock
);
1301 dev_err(dev
, "%s: Can't find device in list\n",
1306 static DEVICE_ATTR(new_device
, S_IWUSR
, NULL
, i2c_sysfs_new_device
);
1307 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device
, S_IWUSR
, NULL
,
1308 i2c_sysfs_delete_device
);
1310 static struct attribute
*i2c_adapter_attrs
[] = {
1311 &dev_attr_name
.attr
,
1312 &dev_attr_new_device
.attr
,
1313 &dev_attr_delete_device
.attr
,
1317 static struct attribute_group i2c_adapter_attr_group
= {
1318 .attrs
= i2c_adapter_attrs
,
1321 static const struct attribute_group
*i2c_adapter_attr_groups
[] = {
1322 &i2c_adapter_attr_group
,
1326 struct device_type i2c_adapter_type
= {
1327 .groups
= i2c_adapter_attr_groups
,
1328 .release
= i2c_adapter_dev_release
,
1330 EXPORT_SYMBOL_GPL(i2c_adapter_type
);
1333 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1334 * @dev: device, probably from some driver model iterator
1336 * When traversing the driver model tree, perhaps using driver model
1337 * iterators like @device_for_each_child(), you can't assume very much
1338 * about the nodes you find. Use this function to avoid oopses caused
1339 * by wrongly treating some non-I2C device as an i2c_adapter.
1341 struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
)
1343 return (dev
->type
== &i2c_adapter_type
)
1344 ? to_i2c_adapter(dev
)
1347 EXPORT_SYMBOL(i2c_verify_adapter
);
1349 #ifdef CONFIG_I2C_COMPAT
1350 static struct class_compat
*i2c_adapter_compat_class
;
1353 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
1355 struct i2c_devinfo
*devinfo
;
1357 down_read(&__i2c_board_lock
);
1358 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
1359 if (devinfo
->busnum
== adapter
->nr
1360 && !i2c_new_device(adapter
,
1361 &devinfo
->board_info
))
1362 dev_err(&adapter
->dev
,
1363 "Can't create device at 0x%02x\n",
1364 devinfo
->board_info
.addr
);
1366 up_read(&__i2c_board_lock
);
1369 /* OF support code */
1371 #if IS_ENABLED(CONFIG_OF)
1372 static struct i2c_client
*of_i2c_register_device(struct i2c_adapter
*adap
,
1373 struct device_node
*node
)
1375 struct i2c_client
*result
;
1376 struct i2c_board_info info
= {};
1377 struct dev_archdata dev_ad
= {};
1381 dev_dbg(&adap
->dev
, "of_i2c: register %s\n", node
->full_name
);
1383 if (of_modalias_node(node
, info
.type
, sizeof(info
.type
)) < 0) {
1384 dev_err(&adap
->dev
, "of_i2c: modalias failure on %s\n",
1386 return ERR_PTR(-EINVAL
);
1389 addr
= of_get_property(node
, "reg", &len
);
1390 if (!addr
|| (len
< sizeof(int))) {
1391 dev_err(&adap
->dev
, "of_i2c: invalid reg on %s\n",
1393 return ERR_PTR(-EINVAL
);
1396 info
.addr
= be32_to_cpup(addr
);
1397 if (info
.addr
> (1 << 10) - 1) {
1398 dev_err(&adap
->dev
, "of_i2c: invalid addr=%x on %s\n",
1399 info
.addr
, node
->full_name
);
1400 return ERR_PTR(-EINVAL
);
1403 info
.irq
= irq_of_parse_and_map(node
, 0);
1404 info
.of_node
= of_node_get(node
);
1405 info
.archdata
= &dev_ad
;
1407 if (of_get_property(node
, "wakeup-source", NULL
))
1408 info
.flags
|= I2C_CLIENT_WAKE
;
1410 request_module("%s%s", I2C_MODULE_PREFIX
, info
.type
);
1412 result
= i2c_new_device(adap
, &info
);
1413 if (result
== NULL
) {
1414 dev_err(&adap
->dev
, "of_i2c: Failure registering %s\n",
1417 irq_dispose_mapping(info
.irq
);
1418 return ERR_PTR(-EINVAL
);
1423 static void of_i2c_register_devices(struct i2c_adapter
*adap
)
1425 struct device_node
*node
;
1427 /* Only register child devices if the adapter has a node pointer set */
1428 if (!adap
->dev
.of_node
)
1431 dev_dbg(&adap
->dev
, "of_i2c: walking child nodes\n");
1433 for_each_available_child_of_node(adap
->dev
.of_node
, node
)
1434 of_i2c_register_device(adap
, node
);
1437 static int of_dev_node_match(struct device
*dev
, void *data
)
1439 return dev
->of_node
== data
;
1442 /* must call put_device() when done with returned i2c_client device */
1443 struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
)
1447 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1452 return i2c_verify_client(dev
);
1454 EXPORT_SYMBOL(of_find_i2c_device_by_node
);
1456 /* must call put_device() when done with returned i2c_adapter device */
1457 struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
)
1461 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1466 return i2c_verify_adapter(dev
);
1468 EXPORT_SYMBOL(of_find_i2c_adapter_by_node
);
1470 static void of_i2c_register_devices(struct i2c_adapter
*adap
) { }
1471 #endif /* CONFIG_OF */
1473 static int i2c_do_add_adapter(struct i2c_driver
*driver
,
1474 struct i2c_adapter
*adap
)
1476 /* Detect supported devices on that bus, and instantiate them */
1477 i2c_detect(adap
, driver
);
1479 /* Let legacy drivers scan this bus for matching devices */
1480 if (driver
->attach_adapter
) {
1481 dev_warn(&adap
->dev
, "%s: attach_adapter method is deprecated\n",
1482 driver
->driver
.name
);
1483 dev_warn(&adap
->dev
, "Please use another way to instantiate "
1484 "your i2c_client\n");
1485 /* We ignore the return code; if it fails, too bad */
1486 driver
->attach_adapter(adap
);
1491 static int __process_new_adapter(struct device_driver
*d
, void *data
)
1493 return i2c_do_add_adapter(to_i2c_driver(d
), data
);
1496 static int i2c_register_adapter(struct i2c_adapter
*adap
)
1500 /* Can't register until after driver model init */
1501 if (unlikely(WARN_ON(!i2c_bus_type
.p
))) {
1507 if (unlikely(adap
->name
[0] == '\0')) {
1508 pr_err("i2c-core: Attempt to register an adapter with "
1512 if (unlikely(!adap
->algo
)) {
1513 pr_err("i2c-core: Attempt to register adapter '%s' with "
1514 "no algo!\n", adap
->name
);
1518 rt_mutex_init(&adap
->bus_lock
);
1519 mutex_init(&adap
->userspace_clients_lock
);
1520 INIT_LIST_HEAD(&adap
->userspace_clients
);
1522 /* Set default timeout to 1 second if not already set */
1523 if (adap
->timeout
== 0)
1526 dev_set_name(&adap
->dev
, "i2c-%d", adap
->nr
);
1527 adap
->dev
.bus
= &i2c_bus_type
;
1528 adap
->dev
.type
= &i2c_adapter_type
;
1529 res
= device_register(&adap
->dev
);
1533 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
1535 #ifdef CONFIG_I2C_COMPAT
1536 res
= class_compat_create_link(i2c_adapter_compat_class
, &adap
->dev
,
1539 dev_warn(&adap
->dev
,
1540 "Failed to create compatibility class link\n");
1543 /* bus recovery specific initialization */
1544 if (adap
->bus_recovery_info
) {
1545 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
1547 if (!bri
->recover_bus
) {
1548 dev_err(&adap
->dev
, "No recover_bus() found, not using recovery\n");
1549 adap
->bus_recovery_info
= NULL
;
1553 /* Generic GPIO recovery */
1554 if (bri
->recover_bus
== i2c_generic_gpio_recovery
) {
1555 if (!gpio_is_valid(bri
->scl_gpio
)) {
1556 dev_err(&adap
->dev
, "Invalid SCL gpio, not using recovery\n");
1557 adap
->bus_recovery_info
= NULL
;
1561 if (gpio_is_valid(bri
->sda_gpio
))
1562 bri
->get_sda
= get_sda_gpio_value
;
1564 bri
->get_sda
= NULL
;
1566 bri
->get_scl
= get_scl_gpio_value
;
1567 bri
->set_scl
= set_scl_gpio_value
;
1568 } else if (!bri
->set_scl
|| !bri
->get_scl
) {
1569 /* Generic SCL recovery */
1570 dev_err(&adap
->dev
, "No {get|set}_gpio() found, not using recovery\n");
1571 adap
->bus_recovery_info
= NULL
;
1576 /* create pre-declared device nodes */
1577 of_i2c_register_devices(adap
);
1578 acpi_i2c_register_devices(adap
);
1579 acpi_i2c_install_space_handler(adap
);
1581 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
1582 i2c_scan_static_board_info(adap
);
1584 /* Notify drivers */
1585 mutex_lock(&core_lock
);
1586 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
, __process_new_adapter
);
1587 mutex_unlock(&core_lock
);
1592 mutex_lock(&core_lock
);
1593 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1594 mutex_unlock(&core_lock
);
1599 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1600 * @adap: the adapter to register (with adap->nr initialized)
1601 * Context: can sleep
1603 * See i2c_add_numbered_adapter() for details.
1605 static int __i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1609 mutex_lock(&core_lock
);
1610 id
= idr_alloc(&i2c_adapter_idr
, adap
, adap
->nr
, adap
->nr
+ 1,
1612 mutex_unlock(&core_lock
);
1614 return id
== -ENOSPC
? -EBUSY
: id
;
1616 return i2c_register_adapter(adap
);
1620 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1621 * @adapter: the adapter to add
1622 * Context: can sleep
1624 * This routine is used to declare an I2C adapter when its bus number
1625 * doesn't matter or when its bus number is specified by an dt alias.
1626 * Examples of bases when the bus number doesn't matter: I2C adapters
1627 * dynamically added by USB links or PCI plugin cards.
1629 * When this returns zero, a new bus number was allocated and stored
1630 * in adap->nr, and the specified adapter became available for clients.
1631 * Otherwise, a negative errno value is returned.
1633 int i2c_add_adapter(struct i2c_adapter
*adapter
)
1635 struct device
*dev
= &adapter
->dev
;
1639 id
= of_alias_get_id(dev
->of_node
, "i2c");
1642 return __i2c_add_numbered_adapter(adapter
);
1646 mutex_lock(&core_lock
);
1647 id
= idr_alloc(&i2c_adapter_idr
, adapter
,
1648 __i2c_first_dynamic_bus_num
, 0, GFP_KERNEL
);
1649 mutex_unlock(&core_lock
);
1655 return i2c_register_adapter(adapter
);
1657 EXPORT_SYMBOL(i2c_add_adapter
);
1660 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1661 * @adap: the adapter to register (with adap->nr initialized)
1662 * Context: can sleep
1664 * This routine is used to declare an I2C adapter when its bus number
1665 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1666 * or otherwise built in to the system's mainboard, and where i2c_board_info
1667 * is used to properly configure I2C devices.
1669 * If the requested bus number is set to -1, then this function will behave
1670 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1672 * If no devices have pre-been declared for this bus, then be sure to
1673 * register the adapter before any dynamically allocated ones. Otherwise
1674 * the required bus ID may not be available.
1676 * When this returns zero, the specified adapter became available for
1677 * clients using the bus number provided in adap->nr. Also, the table
1678 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1679 * and the appropriate driver model device nodes are created. Otherwise, a
1680 * negative errno value is returned.
1682 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1684 if (adap
->nr
== -1) /* -1 means dynamically assign bus id */
1685 return i2c_add_adapter(adap
);
1687 return __i2c_add_numbered_adapter(adap
);
1689 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
1691 static void i2c_do_del_adapter(struct i2c_driver
*driver
,
1692 struct i2c_adapter
*adapter
)
1694 struct i2c_client
*client
, *_n
;
1696 /* Remove the devices we created ourselves as the result of hardware
1697 * probing (using a driver's detect method) */
1698 list_for_each_entry_safe(client
, _n
, &driver
->clients
, detected
) {
1699 if (client
->adapter
== adapter
) {
1700 dev_dbg(&adapter
->dev
, "Removing %s at 0x%x\n",
1701 client
->name
, client
->addr
);
1702 list_del(&client
->detected
);
1703 i2c_unregister_device(client
);
1708 static int __unregister_client(struct device
*dev
, void *dummy
)
1710 struct i2c_client
*client
= i2c_verify_client(dev
);
1711 if (client
&& strcmp(client
->name
, "dummy"))
1712 i2c_unregister_device(client
);
1716 static int __unregister_dummy(struct device
*dev
, void *dummy
)
1718 struct i2c_client
*client
= i2c_verify_client(dev
);
1720 i2c_unregister_device(client
);
1724 static int __process_removed_adapter(struct device_driver
*d
, void *data
)
1726 i2c_do_del_adapter(to_i2c_driver(d
), data
);
1731 * i2c_del_adapter - unregister I2C adapter
1732 * @adap: the adapter being unregistered
1733 * Context: can sleep
1735 * This unregisters an I2C adapter which was previously registered
1736 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1738 void i2c_del_adapter(struct i2c_adapter
*adap
)
1740 struct i2c_adapter
*found
;
1741 struct i2c_client
*client
, *next
;
1743 /* First make sure that this adapter was ever added */
1744 mutex_lock(&core_lock
);
1745 found
= idr_find(&i2c_adapter_idr
, adap
->nr
);
1746 mutex_unlock(&core_lock
);
1747 if (found
!= adap
) {
1748 pr_debug("i2c-core: attempting to delete unregistered "
1749 "adapter [%s]\n", adap
->name
);
1753 acpi_i2c_remove_space_handler(adap
);
1754 /* Tell drivers about this removal */
1755 mutex_lock(&core_lock
);
1756 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
1757 __process_removed_adapter
);
1758 mutex_unlock(&core_lock
);
1760 /* Remove devices instantiated from sysfs */
1761 mutex_lock_nested(&adap
->userspace_clients_lock
,
1762 i2c_adapter_depth(adap
));
1763 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1765 dev_dbg(&adap
->dev
, "Removing %s at 0x%x\n", client
->name
,
1767 list_del(&client
->detected
);
1768 i2c_unregister_device(client
);
1770 mutex_unlock(&adap
->userspace_clients_lock
);
1772 /* Detach any active clients. This can't fail, thus we do not
1773 * check the returned value. This is a two-pass process, because
1774 * we can't remove the dummy devices during the first pass: they
1775 * could have been instantiated by real devices wishing to clean
1776 * them up properly, so we give them a chance to do that first. */
1777 device_for_each_child(&adap
->dev
, NULL
, __unregister_client
);
1778 device_for_each_child(&adap
->dev
, NULL
, __unregister_dummy
);
1780 #ifdef CONFIG_I2C_COMPAT
1781 class_compat_remove_link(i2c_adapter_compat_class
, &adap
->dev
,
1785 /* device name is gone after device_unregister */
1786 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
1788 /* clean up the sysfs representation */
1789 init_completion(&adap
->dev_released
);
1790 device_unregister(&adap
->dev
);
1792 /* wait for sysfs to drop all references */
1793 wait_for_completion(&adap
->dev_released
);
1796 mutex_lock(&core_lock
);
1797 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1798 mutex_unlock(&core_lock
);
1800 /* Clear the device structure in case this adapter is ever going to be
1802 memset(&adap
->dev
, 0, sizeof(adap
->dev
));
1804 EXPORT_SYMBOL(i2c_del_adapter
);
1806 /* ------------------------------------------------------------------------- */
1808 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *))
1812 mutex_lock(&core_lock
);
1813 res
= bus_for_each_dev(&i2c_bus_type
, NULL
, data
, fn
);
1814 mutex_unlock(&core_lock
);
1818 EXPORT_SYMBOL_GPL(i2c_for_each_dev
);
1820 static int __process_new_driver(struct device
*dev
, void *data
)
1822 if (dev
->type
!= &i2c_adapter_type
)
1824 return i2c_do_add_adapter(data
, to_i2c_adapter(dev
));
1828 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1829 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1832 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
1836 /* Can't register until after driver model init */
1837 if (unlikely(WARN_ON(!i2c_bus_type
.p
)))
1840 /* add the driver to the list of i2c drivers in the driver core */
1841 driver
->driver
.owner
= owner
;
1842 driver
->driver
.bus
= &i2c_bus_type
;
1844 /* When registration returns, the driver core
1845 * will have called probe() for all matching-but-unbound devices.
1847 res
= driver_register(&driver
->driver
);
1851 /* Drivers should switch to dev_pm_ops instead. */
1852 if (driver
->suspend
)
1853 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1854 driver
->driver
.name
);
1856 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1857 driver
->driver
.name
);
1859 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
1861 INIT_LIST_HEAD(&driver
->clients
);
1862 /* Walk the adapters that are already present */
1863 i2c_for_each_dev(driver
, __process_new_driver
);
1867 EXPORT_SYMBOL(i2c_register_driver
);
1869 static int __process_removed_driver(struct device
*dev
, void *data
)
1871 if (dev
->type
== &i2c_adapter_type
)
1872 i2c_do_del_adapter(data
, to_i2c_adapter(dev
));
1877 * i2c_del_driver - unregister I2C driver
1878 * @driver: the driver being unregistered
1879 * Context: can sleep
1881 void i2c_del_driver(struct i2c_driver
*driver
)
1883 i2c_for_each_dev(driver
, __process_removed_driver
);
1885 driver_unregister(&driver
->driver
);
1886 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
1888 EXPORT_SYMBOL(i2c_del_driver
);
1890 /* ------------------------------------------------------------------------- */
1893 * i2c_use_client - increments the reference count of the i2c client structure
1894 * @client: the client being referenced
1896 * Each live reference to a client should be refcounted. The driver model does
1897 * that automatically as part of driver binding, so that most drivers don't
1898 * need to do this explicitly: they hold a reference until they're unbound
1901 * A pointer to the client with the incremented reference counter is returned.
1903 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
1905 if (client
&& get_device(&client
->dev
))
1909 EXPORT_SYMBOL(i2c_use_client
);
1912 * i2c_release_client - release a use of the i2c client structure
1913 * @client: the client being no longer referenced
1915 * Must be called when a user of a client is finished with it.
1917 void i2c_release_client(struct i2c_client
*client
)
1920 put_device(&client
->dev
);
1922 EXPORT_SYMBOL(i2c_release_client
);
1924 struct i2c_cmd_arg
{
1929 static int i2c_cmd(struct device
*dev
, void *_arg
)
1931 struct i2c_client
*client
= i2c_verify_client(dev
);
1932 struct i2c_cmd_arg
*arg
= _arg
;
1933 struct i2c_driver
*driver
;
1935 if (!client
|| !client
->dev
.driver
)
1938 driver
= to_i2c_driver(client
->dev
.driver
);
1939 if (driver
->command
)
1940 driver
->command(client
, arg
->cmd
, arg
->arg
);
1944 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
1946 struct i2c_cmd_arg cmd_arg
;
1950 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
1952 EXPORT_SYMBOL(i2c_clients_command
);
1954 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
1955 static int of_i2c_notify(struct notifier_block
*nb
, unsigned long action
,
1958 struct of_reconfig_data
*rd
= arg
;
1959 struct i2c_adapter
*adap
;
1960 struct i2c_client
*client
;
1962 switch (of_reconfig_get_state_change(action
, rd
)) {
1963 case OF_RECONFIG_CHANGE_ADD
:
1964 adap
= of_find_i2c_adapter_by_node(rd
->dn
->parent
);
1966 return NOTIFY_OK
; /* not for us */
1968 client
= of_i2c_register_device(adap
, rd
->dn
);
1969 put_device(&adap
->dev
);
1971 if (IS_ERR(client
)) {
1972 pr_err("%s: failed to create for '%s'\n",
1973 __func__
, rd
->dn
->full_name
);
1974 return notifier_from_errno(PTR_ERR(client
));
1977 case OF_RECONFIG_CHANGE_REMOVE
:
1978 /* find our device by node */
1979 client
= of_find_i2c_device_by_node(rd
->dn
);
1981 return NOTIFY_OK
; /* no? not meant for us */
1983 /* unregister takes one ref away */
1984 i2c_unregister_device(client
);
1986 /* and put the reference of the find */
1987 put_device(&client
->dev
);
1993 static struct notifier_block i2c_of_notifier
= {
1994 .notifier_call
= of_i2c_notify
,
1997 extern struct notifier_block i2c_of_notifier
;
1998 #endif /* CONFIG_OF_DYNAMIC */
2000 static int __init
i2c_init(void)
2004 retval
= bus_register(&i2c_bus_type
);
2007 #ifdef CONFIG_I2C_COMPAT
2008 i2c_adapter_compat_class
= class_compat_register("i2c-adapter");
2009 if (!i2c_adapter_compat_class
) {
2014 retval
= i2c_add_driver(&dummy_driver
);
2018 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
2019 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier
));
2024 #ifdef CONFIG_I2C_COMPAT
2025 class_compat_unregister(i2c_adapter_compat_class
);
2028 bus_unregister(&i2c_bus_type
);
2032 static void __exit
i2c_exit(void)
2034 if (IS_ENABLED(CONFIG_OF_DYNAMIC
))
2035 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier
));
2036 i2c_del_driver(&dummy_driver
);
2037 #ifdef CONFIG_I2C_COMPAT
2038 class_compat_unregister(i2c_adapter_compat_class
);
2040 bus_unregister(&i2c_bus_type
);
2041 tracepoint_synchronize_unregister();
2044 /* We must initialize early, because some subsystems register i2c drivers
2045 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2047 postcore_initcall(i2c_init
);
2048 module_exit(i2c_exit
);
2050 /* ----------------------------------------------------
2051 * the functional interface to the i2c busses.
2052 * ----------------------------------------------------
2056 * __i2c_transfer - unlocked flavor of i2c_transfer
2057 * @adap: Handle to I2C bus
2058 * @msgs: One or more messages to execute before STOP is issued to
2059 * terminate the operation; each message begins with a START.
2060 * @num: Number of messages to be executed.
2062 * Returns negative errno, else the number of messages executed.
2064 * Adapter lock must be held when calling this function. No debug logging
2065 * takes place. adap->algo->master_xfer existence isn't checked.
2067 int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2069 unsigned long orig_jiffies
;
2072 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2073 * enabled. This is an efficient way of keeping the for-loop from
2074 * being executed when not needed.
2076 if (static_key_false(&i2c_trace_msg
)) {
2078 for (i
= 0; i
< num
; i
++)
2079 if (msgs
[i
].flags
& I2C_M_RD
)
2080 trace_i2c_read(adap
, &msgs
[i
], i
);
2082 trace_i2c_write(adap
, &msgs
[i
], i
);
2085 /* Retry automatically on arbitration loss */
2086 orig_jiffies
= jiffies
;
2087 for (ret
= 0, try = 0; try <= adap
->retries
; try++) {
2088 ret
= adap
->algo
->master_xfer(adap
, msgs
, num
);
2091 if (time_after(jiffies
, orig_jiffies
+ adap
->timeout
))
2095 if (static_key_false(&i2c_trace_msg
)) {
2097 for (i
= 0; i
< ret
; i
++)
2098 if (msgs
[i
].flags
& I2C_M_RD
)
2099 trace_i2c_reply(adap
, &msgs
[i
], i
);
2100 trace_i2c_result(adap
, i
, ret
);
2105 EXPORT_SYMBOL(__i2c_transfer
);
2108 * i2c_transfer - execute a single or combined I2C message
2109 * @adap: Handle to I2C bus
2110 * @msgs: One or more messages to execute before STOP is issued to
2111 * terminate the operation; each message begins with a START.
2112 * @num: Number of messages to be executed.
2114 * Returns negative errno, else the number of messages executed.
2116 * Note that there is no requirement that each message be sent to
2117 * the same slave address, although that is the most common model.
2119 int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
2123 /* REVISIT the fault reporting model here is weak:
2125 * - When we get an error after receiving N bytes from a slave,
2126 * there is no way to report "N".
2128 * - When we get a NAK after transmitting N bytes to a slave,
2129 * there is no way to report "N" ... or to let the master
2130 * continue executing the rest of this combined message, if
2131 * that's the appropriate response.
2133 * - When for example "num" is two and we successfully complete
2134 * the first message but get an error part way through the
2135 * second, it's unclear whether that should be reported as
2136 * one (discarding status on the second message) or errno
2137 * (discarding status on the first one).
2140 if (adap
->algo
->master_xfer
) {
2142 for (ret
= 0; ret
< num
; ret
++) {
2143 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
2144 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
2145 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
2146 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
2150 if (in_atomic() || irqs_disabled()) {
2151 ret
= i2c_trylock_adapter(adap
);
2153 /* I2C activity is ongoing. */
2156 i2c_lock_adapter(adap
);
2159 ret
= __i2c_transfer(adap
, msgs
, num
);
2160 i2c_unlock_adapter(adap
);
2164 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
2168 EXPORT_SYMBOL(i2c_transfer
);
2171 * i2c_master_send - issue a single I2C message in master transmit mode
2172 * @client: Handle to slave device
2173 * @buf: Data that will be written to the slave
2174 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2176 * Returns negative errno, or else the number of bytes written.
2178 int i2c_master_send(const struct i2c_client
*client
, const char *buf
, int count
)
2181 struct i2c_adapter
*adap
= client
->adapter
;
2184 msg
.addr
= client
->addr
;
2185 msg
.flags
= client
->flags
& I2C_M_TEN
;
2187 msg
.buf
= (char *)buf
;
2189 ret
= i2c_transfer(adap
, &msg
, 1);
2192 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2193 * transmitted, else error code.
2195 return (ret
== 1) ? count
: ret
;
2197 EXPORT_SYMBOL(i2c_master_send
);
2200 * i2c_master_recv - issue a single I2C message in master receive mode
2201 * @client: Handle to slave device
2202 * @buf: Where to store data read from slave
2203 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2205 * Returns negative errno, or else the number of bytes read.
2207 int i2c_master_recv(const struct i2c_client
*client
, char *buf
, int count
)
2209 struct i2c_adapter
*adap
= client
->adapter
;
2213 msg
.addr
= client
->addr
;
2214 msg
.flags
= client
->flags
& I2C_M_TEN
;
2215 msg
.flags
|= I2C_M_RD
;
2219 ret
= i2c_transfer(adap
, &msg
, 1);
2222 * If everything went ok (i.e. 1 msg received), return #bytes received,
2225 return (ret
== 1) ? count
: ret
;
2227 EXPORT_SYMBOL(i2c_master_recv
);
2229 /* ----------------------------------------------------
2230 * the i2c address scanning function
2231 * Will not work for 10-bit addresses!
2232 * ----------------------------------------------------
2236 * Legacy default probe function, mostly relevant for SMBus. The default
2237 * probe method is a quick write, but it is known to corrupt the 24RF08
2238 * EEPROMs due to a state machine bug, and could also irreversibly
2239 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2240 * we use a short byte read instead. Also, some bus drivers don't implement
2241 * quick write, so we fallback to a byte read in that case too.
2242 * On x86, there is another special case for FSC hardware monitoring chips,
2243 * which want regular byte reads (address 0x73.) Fortunately, these are the
2244 * only known chips using this I2C address on PC hardware.
2245 * Returns 1 if probe succeeded, 0 if not.
2247 static int i2c_default_probe(struct i2c_adapter
*adap
, unsigned short addr
)
2250 union i2c_smbus_data dummy
;
2253 if (addr
== 0x73 && (adap
->class & I2C_CLASS_HWMON
)
2254 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
2255 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2256 I2C_SMBUS_BYTE_DATA
, &dummy
);
2259 if (!((addr
& ~0x07) == 0x30 || (addr
& ~0x0f) == 0x50)
2260 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
))
2261 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_WRITE
, 0,
2262 I2C_SMBUS_QUICK
, NULL
);
2263 else if (i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
))
2264 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2265 I2C_SMBUS_BYTE
, &dummy
);
2267 dev_warn(&adap
->dev
, "No suitable probing method supported for address 0x%02X\n",
2275 static int i2c_detect_address(struct i2c_client
*temp_client
,
2276 struct i2c_driver
*driver
)
2278 struct i2c_board_info info
;
2279 struct i2c_adapter
*adapter
= temp_client
->adapter
;
2280 int addr
= temp_client
->addr
;
2283 /* Make sure the address is valid */
2284 err
= i2c_check_addr_validity(addr
);
2286 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
2291 /* Skip if already in use */
2292 if (i2c_check_addr_busy(adapter
, addr
))
2295 /* Make sure there is something at this address */
2296 if (!i2c_default_probe(adapter
, addr
))
2299 /* Finally call the custom detection function */
2300 memset(&info
, 0, sizeof(struct i2c_board_info
));
2302 err
= driver
->detect(temp_client
, &info
);
2304 /* -ENODEV is returned if the detection fails. We catch it
2305 here as this isn't an error. */
2306 return err
== -ENODEV
? 0 : err
;
2309 /* Consistency check */
2310 if (info
.type
[0] == '\0') {
2311 dev_err(&adapter
->dev
, "%s detection function provided "
2312 "no name for 0x%x\n", driver
->driver
.name
,
2315 struct i2c_client
*client
;
2317 /* Detection succeeded, instantiate the device */
2318 if (adapter
->class & I2C_CLASS_DEPRECATED
)
2319 dev_warn(&adapter
->dev
,
2320 "This adapter will soon drop class based instantiation of devices. "
2321 "Please make sure client 0x%02x gets instantiated by other means. "
2322 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2325 dev_dbg(&adapter
->dev
, "Creating %s at 0x%02x\n",
2326 info
.type
, info
.addr
);
2327 client
= i2c_new_device(adapter
, &info
);
2329 list_add_tail(&client
->detected
, &driver
->clients
);
2331 dev_err(&adapter
->dev
, "Failed creating %s at 0x%02x\n",
2332 info
.type
, info
.addr
);
2337 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
)
2339 const unsigned short *address_list
;
2340 struct i2c_client
*temp_client
;
2342 int adap_id
= i2c_adapter_id(adapter
);
2344 address_list
= driver
->address_list
;
2345 if (!driver
->detect
|| !address_list
)
2348 /* Warn that the adapter lost class based instantiation */
2349 if (adapter
->class == I2C_CLASS_DEPRECATED
) {
2350 dev_dbg(&adapter
->dev
,
2351 "This adapter dropped support for I2C classes and "
2352 "won't auto-detect %s devices anymore. If you need it, check "
2353 "'Documentation/i2c/instantiating-devices' for alternatives.\n",
2354 driver
->driver
.name
);
2358 /* Stop here if the classes do not match */
2359 if (!(adapter
->class & driver
->class))
2362 /* Set up a temporary client to help detect callback */
2363 temp_client
= kzalloc(sizeof(struct i2c_client
), GFP_KERNEL
);
2366 temp_client
->adapter
= adapter
;
2368 for (i
= 0; address_list
[i
] != I2C_CLIENT_END
; i
+= 1) {
2369 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
2370 "addr 0x%02x\n", adap_id
, address_list
[i
]);
2371 temp_client
->addr
= address_list
[i
];
2372 err
= i2c_detect_address(temp_client
, driver
);
2381 int i2c_probe_func_quick_read(struct i2c_adapter
*adap
, unsigned short addr
)
2383 return i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
2384 I2C_SMBUS_QUICK
, NULL
) >= 0;
2386 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read
);
2389 i2c_new_probed_device(struct i2c_adapter
*adap
,
2390 struct i2c_board_info
*info
,
2391 unsigned short const *addr_list
,
2392 int (*probe
)(struct i2c_adapter
*, unsigned short addr
))
2397 probe
= i2c_default_probe
;
2399 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
2400 /* Check address validity */
2401 if (i2c_check_addr_validity(addr_list
[i
]) < 0) {
2402 dev_warn(&adap
->dev
, "Invalid 7-bit address "
2403 "0x%02x\n", addr_list
[i
]);
2407 /* Check address availability */
2408 if (i2c_check_addr_busy(adap
, addr_list
[i
])) {
2409 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
2410 "use, not probing\n", addr_list
[i
]);
2414 /* Test address responsiveness */
2415 if (probe(adap
, addr_list
[i
]))
2419 if (addr_list
[i
] == I2C_CLIENT_END
) {
2420 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
2424 info
->addr
= addr_list
[i
];
2425 return i2c_new_device(adap
, info
);
2427 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
2429 struct i2c_adapter
*i2c_get_adapter(int nr
)
2431 struct i2c_adapter
*adapter
;
2433 mutex_lock(&core_lock
);
2434 adapter
= idr_find(&i2c_adapter_idr
, nr
);
2435 if (adapter
&& !try_module_get(adapter
->owner
))
2438 mutex_unlock(&core_lock
);
2441 EXPORT_SYMBOL(i2c_get_adapter
);
2443 void i2c_put_adapter(struct i2c_adapter
*adap
)
2446 module_put(adap
->owner
);
2448 EXPORT_SYMBOL(i2c_put_adapter
);
2450 /* The SMBus parts */
2452 #define POLY (0x1070U << 3)
2453 static u8
crc8(u16 data
)
2457 for (i
= 0; i
< 8; i
++) {
2462 return (u8
)(data
>> 8);
2465 /* Incremental CRC8 over count bytes in the array pointed to by p */
2466 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
2470 for (i
= 0; i
< count
; i
++)
2471 crc
= crc8((crc
^ p
[i
]) << 8);
2475 /* Assume a 7-bit address, which is reasonable for SMBus */
2476 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
2478 /* The address will be sent first */
2479 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
2480 pec
= i2c_smbus_pec(pec
, &addr
, 1);
2482 /* The data buffer follows */
2483 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
2486 /* Used for write only transactions */
2487 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
2489 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
2493 /* Return <0 on CRC error
2494 If there was a write before this read (most cases) we need to take the
2495 partial CRC from the write part into account.
2496 Note that this function does modify the message (we need to decrease the
2497 message length to hide the CRC byte from the caller). */
2498 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
2500 u8 rpec
= msg
->buf
[--msg
->len
];
2501 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
2504 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2512 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2513 * @client: Handle to slave device
2515 * This executes the SMBus "receive byte" protocol, returning negative errno
2516 * else the byte received from the device.
2518 s32
i2c_smbus_read_byte(const struct i2c_client
*client
)
2520 union i2c_smbus_data data
;
2523 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2525 I2C_SMBUS_BYTE
, &data
);
2526 return (status
< 0) ? status
: data
.byte
;
2528 EXPORT_SYMBOL(i2c_smbus_read_byte
);
2531 * i2c_smbus_write_byte - SMBus "send byte" protocol
2532 * @client: Handle to slave device
2533 * @value: Byte to be sent
2535 * This executes the SMBus "send byte" protocol, returning negative errno
2536 * else zero on success.
2538 s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
)
2540 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2541 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
2543 EXPORT_SYMBOL(i2c_smbus_write_byte
);
2546 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2547 * @client: Handle to slave device
2548 * @command: Byte interpreted by slave
2550 * This executes the SMBus "read byte" protocol, returning negative errno
2551 * else a data byte received from the device.
2553 s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
, u8 command
)
2555 union i2c_smbus_data data
;
2558 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2559 I2C_SMBUS_READ
, command
,
2560 I2C_SMBUS_BYTE_DATA
, &data
);
2561 return (status
< 0) ? status
: data
.byte
;
2563 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
2566 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2567 * @client: Handle to slave device
2568 * @command: Byte interpreted by slave
2569 * @value: Byte being written
2571 * This executes the SMBus "write byte" protocol, returning negative errno
2572 * else zero on success.
2574 s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
, u8 command
,
2577 union i2c_smbus_data data
;
2579 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2580 I2C_SMBUS_WRITE
, command
,
2581 I2C_SMBUS_BYTE_DATA
, &data
);
2583 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
2586 * i2c_smbus_read_word_data - SMBus "read word" protocol
2587 * @client: Handle to slave device
2588 * @command: Byte interpreted by slave
2590 * This executes the SMBus "read word" protocol, returning negative errno
2591 * else a 16-bit unsigned "word" received from the device.
2593 s32
i2c_smbus_read_word_data(const struct i2c_client
*client
, u8 command
)
2595 union i2c_smbus_data data
;
2598 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2599 I2C_SMBUS_READ
, command
,
2600 I2C_SMBUS_WORD_DATA
, &data
);
2601 return (status
< 0) ? status
: data
.word
;
2603 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
2606 * i2c_smbus_write_word_data - SMBus "write word" protocol
2607 * @client: Handle to slave device
2608 * @command: Byte interpreted by slave
2609 * @value: 16-bit "word" being written
2611 * This executes the SMBus "write word" protocol, returning negative errno
2612 * else zero on success.
2614 s32
i2c_smbus_write_word_data(const struct i2c_client
*client
, u8 command
,
2617 union i2c_smbus_data data
;
2619 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2620 I2C_SMBUS_WRITE
, command
,
2621 I2C_SMBUS_WORD_DATA
, &data
);
2623 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
2626 * i2c_smbus_read_block_data - SMBus "block read" protocol
2627 * @client: Handle to slave device
2628 * @command: Byte interpreted by slave
2629 * @values: Byte array into which data will be read; big enough to hold
2630 * the data returned by the slave. SMBus allows at most 32 bytes.
2632 * This executes the SMBus "block read" protocol, returning negative errno
2633 * else the number of data bytes in the slave's response.
2635 * Note that using this function requires that the client's adapter support
2636 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2637 * support this; its emulation through I2C messaging relies on a specific
2638 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2640 s32
i2c_smbus_read_block_data(const struct i2c_client
*client
, u8 command
,
2643 union i2c_smbus_data data
;
2646 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2647 I2C_SMBUS_READ
, command
,
2648 I2C_SMBUS_BLOCK_DATA
, &data
);
2652 memcpy(values
, &data
.block
[1], data
.block
[0]);
2653 return data
.block
[0];
2655 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
2658 * i2c_smbus_write_block_data - SMBus "block write" protocol
2659 * @client: Handle to slave device
2660 * @command: Byte interpreted by slave
2661 * @length: Size of data block; SMBus allows at most 32 bytes
2662 * @values: Byte array which will be written.
2664 * This executes the SMBus "block write" protocol, returning negative errno
2665 * else zero on success.
2667 s32
i2c_smbus_write_block_data(const struct i2c_client
*client
, u8 command
,
2668 u8 length
, const u8
*values
)
2670 union i2c_smbus_data data
;
2672 if (length
> I2C_SMBUS_BLOCK_MAX
)
2673 length
= I2C_SMBUS_BLOCK_MAX
;
2674 data
.block
[0] = length
;
2675 memcpy(&data
.block
[1], values
, length
);
2676 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2677 I2C_SMBUS_WRITE
, command
,
2678 I2C_SMBUS_BLOCK_DATA
, &data
);
2680 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
2682 /* Returns the number of read bytes */
2683 s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2684 u8 length
, u8
*values
)
2686 union i2c_smbus_data data
;
2689 if (length
> I2C_SMBUS_BLOCK_MAX
)
2690 length
= I2C_SMBUS_BLOCK_MAX
;
2691 data
.block
[0] = length
;
2692 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2693 I2C_SMBUS_READ
, command
,
2694 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2698 memcpy(values
, &data
.block
[1], data
.block
[0]);
2699 return data
.block
[0];
2701 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
2703 s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2704 u8 length
, const u8
*values
)
2706 union i2c_smbus_data data
;
2708 if (length
> I2C_SMBUS_BLOCK_MAX
)
2709 length
= I2C_SMBUS_BLOCK_MAX
;
2710 data
.block
[0] = length
;
2711 memcpy(data
.block
+ 1, values
, length
);
2712 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2713 I2C_SMBUS_WRITE
, command
,
2714 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2716 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
2718 /* Simulate a SMBus command using the i2c protocol
2719 No checking of parameters is done! */
2720 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
*adapter
, u16 addr
,
2721 unsigned short flags
,
2722 char read_write
, u8 command
, int size
,
2723 union i2c_smbus_data
*data
)
2725 /* So we need to generate a series of msgs. In the case of writing, we
2726 need to use only one message; when reading, we need two. We initialize
2727 most things with sane defaults, to keep the code below somewhat
2729 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
2730 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
2731 int num
= read_write
== I2C_SMBUS_READ
? 2 : 1;
2735 struct i2c_msg msg
[2] = {
2743 .flags
= flags
| I2C_M_RD
,
2749 msgbuf0
[0] = command
;
2751 case I2C_SMBUS_QUICK
:
2753 /* Special case: The read/write field is used as data */
2754 msg
[0].flags
= flags
| (read_write
== I2C_SMBUS_READ
?
2758 case I2C_SMBUS_BYTE
:
2759 if (read_write
== I2C_SMBUS_READ
) {
2760 /* Special case: only a read! */
2761 msg
[0].flags
= I2C_M_RD
| flags
;
2765 case I2C_SMBUS_BYTE_DATA
:
2766 if (read_write
== I2C_SMBUS_READ
)
2770 msgbuf0
[1] = data
->byte
;
2773 case I2C_SMBUS_WORD_DATA
:
2774 if (read_write
== I2C_SMBUS_READ
)
2778 msgbuf0
[1] = data
->word
& 0xff;
2779 msgbuf0
[2] = data
->word
>> 8;
2782 case I2C_SMBUS_PROC_CALL
:
2783 num
= 2; /* Special case */
2784 read_write
= I2C_SMBUS_READ
;
2787 msgbuf0
[1] = data
->word
& 0xff;
2788 msgbuf0
[2] = data
->word
>> 8;
2790 case I2C_SMBUS_BLOCK_DATA
:
2791 if (read_write
== I2C_SMBUS_READ
) {
2792 msg
[1].flags
|= I2C_M_RECV_LEN
;
2793 msg
[1].len
= 1; /* block length will be added by
2794 the underlying bus driver */
2796 msg
[0].len
= data
->block
[0] + 2;
2797 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
2798 dev_err(&adapter
->dev
,
2799 "Invalid block write size %d\n",
2803 for (i
= 1; i
< msg
[0].len
; i
++)
2804 msgbuf0
[i
] = data
->block
[i
-1];
2807 case I2C_SMBUS_BLOCK_PROC_CALL
:
2808 num
= 2; /* Another special case */
2809 read_write
= I2C_SMBUS_READ
;
2810 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
2811 dev_err(&adapter
->dev
,
2812 "Invalid block write size %d\n",
2816 msg
[0].len
= data
->block
[0] + 2;
2817 for (i
= 1; i
< msg
[0].len
; i
++)
2818 msgbuf0
[i
] = data
->block
[i
-1];
2819 msg
[1].flags
|= I2C_M_RECV_LEN
;
2820 msg
[1].len
= 1; /* block length will be added by
2821 the underlying bus driver */
2823 case I2C_SMBUS_I2C_BLOCK_DATA
:
2824 if (read_write
== I2C_SMBUS_READ
) {
2825 msg
[1].len
= data
->block
[0];
2827 msg
[0].len
= data
->block
[0] + 1;
2828 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
2829 dev_err(&adapter
->dev
,
2830 "Invalid block write size %d\n",
2834 for (i
= 1; i
<= data
->block
[0]; i
++)
2835 msgbuf0
[i
] = data
->block
[i
];
2839 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
2843 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
2844 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
2846 /* Compute PEC if first message is a write */
2847 if (!(msg
[0].flags
& I2C_M_RD
)) {
2848 if (num
== 1) /* Write only */
2849 i2c_smbus_add_pec(&msg
[0]);
2850 else /* Write followed by read */
2851 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
2853 /* Ask for PEC if last message is a read */
2854 if (msg
[num
-1].flags
& I2C_M_RD
)
2858 status
= i2c_transfer(adapter
, msg
, num
);
2862 /* Check PEC if last message is a read */
2863 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
2864 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
2869 if (read_write
== I2C_SMBUS_READ
)
2871 case I2C_SMBUS_BYTE
:
2872 data
->byte
= msgbuf0
[0];
2874 case I2C_SMBUS_BYTE_DATA
:
2875 data
->byte
= msgbuf1
[0];
2877 case I2C_SMBUS_WORD_DATA
:
2878 case I2C_SMBUS_PROC_CALL
:
2879 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
2881 case I2C_SMBUS_I2C_BLOCK_DATA
:
2882 for (i
= 0; i
< data
->block
[0]; i
++)
2883 data
->block
[i
+1] = msgbuf1
[i
];
2885 case I2C_SMBUS_BLOCK_DATA
:
2886 case I2C_SMBUS_BLOCK_PROC_CALL
:
2887 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
2888 data
->block
[i
] = msgbuf1
[i
];
2895 * i2c_smbus_xfer - execute SMBus protocol operations
2896 * @adapter: Handle to I2C bus
2897 * @addr: Address of SMBus slave on that bus
2898 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2899 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2900 * @command: Byte interpreted by slave, for protocols which use such bytes
2901 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2902 * @data: Data to be read or written
2904 * This executes an SMBus protocol operation, and returns a negative
2905 * errno code else zero on success.
2907 s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
, unsigned short flags
,
2908 char read_write
, u8 command
, int protocol
,
2909 union i2c_smbus_data
*data
)
2911 unsigned long orig_jiffies
;
2915 /* If enabled, the following two tracepoints are conditional on
2916 * read_write and protocol.
2918 trace_smbus_write(adapter
, addr
, flags
, read_write
,
2919 command
, protocol
, data
);
2920 trace_smbus_read(adapter
, addr
, flags
, read_write
,
2923 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
| I2C_CLIENT_SCCB
;
2925 if (adapter
->algo
->smbus_xfer
) {
2926 i2c_lock_adapter(adapter
);
2928 /* Retry automatically on arbitration loss */
2929 orig_jiffies
= jiffies
;
2930 for (res
= 0, try = 0; try <= adapter
->retries
; try++) {
2931 res
= adapter
->algo
->smbus_xfer(adapter
, addr
, flags
,
2932 read_write
, command
,
2936 if (time_after(jiffies
,
2937 orig_jiffies
+ adapter
->timeout
))
2940 i2c_unlock_adapter(adapter
);
2942 if (res
!= -EOPNOTSUPP
|| !adapter
->algo
->master_xfer
)
2945 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2946 * implement native support for the SMBus operation.
2950 res
= i2c_smbus_xfer_emulated(adapter
, addr
, flags
, read_write
,
2951 command
, protocol
, data
);
2954 /* If enabled, the reply tracepoint is conditional on read_write. */
2955 trace_smbus_reply(adapter
, addr
, flags
, read_write
,
2956 command
, protocol
, data
);
2957 trace_smbus_result(adapter
, addr
, flags
, read_write
,
2958 command
, protocol
, res
);
2962 EXPORT_SYMBOL(i2c_smbus_xfer
);
2964 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2965 MODULE_DESCRIPTION("I2C-Bus main module");
2966 MODULE_LICENSE("GPL");