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.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
19 /* ------------------------------------------------------------------------- */
21 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
22 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
23 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
24 Jean Delvare <khali@linux-fr.org>
25 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
26 Michael Lawnick <michael.lawnick.ext@nsn.com>
27 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
28 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
29 (c) 2013 Wolfram Sang <wsa@the-dreams.de>
32 #include <linux/module.h>
33 #include <linux/kernel.h>
34 #include <linux/delay.h>
35 #include <linux/errno.h>
36 #include <linux/gpio.h>
37 #include <linux/slab.h>
38 #include <linux/i2c.h>
39 #include <linux/init.h>
40 #include <linux/idr.h>
41 #include <linux/mutex.h>
43 #include <linux/of_device.h>
44 #include <linux/of_irq.h>
45 #include <linux/completion.h>
46 #include <linux/hardirq.h>
47 #include <linux/irqflags.h>
48 #include <linux/rwsem.h>
49 #include <linux/pm_runtime.h>
50 #include <linux/acpi.h>
51 #include <asm/uaccess.h>
56 /* core_lock protects i2c_adapter_idr, and guarantees
57 that device detection, deletion of detected devices, and attach_adapter
58 calls are serialized */
59 static DEFINE_MUTEX(core_lock
);
60 static DEFINE_IDR(i2c_adapter_idr
);
62 static struct device_type i2c_client_type
;
63 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
);
65 /* ------------------------------------------------------------------------- */
67 static const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
68 const struct i2c_client
*client
)
71 if (strcmp(client
->name
, id
->name
) == 0)
78 static int i2c_device_match(struct device
*dev
, struct device_driver
*drv
)
80 struct i2c_client
*client
= i2c_verify_client(dev
);
81 struct i2c_driver
*driver
;
86 /* Attempt an OF style match */
87 if (of_driver_match_device(dev
, drv
))
90 /* Then ACPI style match */
91 if (acpi_driver_match_device(dev
, drv
))
94 driver
= to_i2c_driver(drv
);
95 /* match on an id table if there is one */
97 return i2c_match_id(driver
->id_table
, client
) != NULL
;
103 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
104 static int i2c_device_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
106 struct i2c_client
*client
= to_i2c_client(dev
);
108 if (add_uevent_var(env
, "MODALIAS=%s%s",
109 I2C_MODULE_PREFIX
, client
->name
))
111 dev_dbg(dev
, "uevent\n");
115 /* i2c bus recovery routines */
116 static int get_scl_gpio_value(struct i2c_adapter
*adap
)
118 return gpio_get_value(adap
->bus_recovery_info
->scl_gpio
);
121 static void set_scl_gpio_value(struct i2c_adapter
*adap
, int val
)
123 gpio_set_value(adap
->bus_recovery_info
->scl_gpio
, val
);
126 static int get_sda_gpio_value(struct i2c_adapter
*adap
)
128 return gpio_get_value(adap
->bus_recovery_info
->sda_gpio
);
131 static int i2c_get_gpios_for_recovery(struct i2c_adapter
*adap
)
133 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
134 struct device
*dev
= &adap
->dev
;
137 ret
= gpio_request_one(bri
->scl_gpio
, GPIOF_OPEN_DRAIN
|
138 GPIOF_OUT_INIT_HIGH
, "i2c-scl");
140 dev_warn(dev
, "Can't get SCL gpio: %d\n", bri
->scl_gpio
);
145 if (gpio_request_one(bri
->sda_gpio
, GPIOF_IN
, "i2c-sda")) {
146 /* work without SDA polling */
147 dev_warn(dev
, "Can't get SDA gpio: %d. Not using SDA polling\n",
156 static void i2c_put_gpios_for_recovery(struct i2c_adapter
*adap
)
158 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
161 gpio_free(bri
->sda_gpio
);
163 gpio_free(bri
->scl_gpio
);
167 * We are generating clock pulses. ndelay() determines durating of clk pulses.
168 * We will generate clock with rate 100 KHz and so duration of both clock levels
169 * is: delay in ns = (10^6 / 100) / 2
171 #define RECOVERY_NDELAY 5000
172 #define RECOVERY_CLK_CNT 9
174 static int i2c_generic_recovery(struct i2c_adapter
*adap
)
176 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
177 int i
= 0, val
= 1, ret
= 0;
179 if (bri
->prepare_recovery
)
180 bri
->prepare_recovery(bri
);
183 * By this time SCL is high, as we need to give 9 falling-rising edges
185 while (i
++ < RECOVERY_CLK_CNT
* 2) {
187 /* Break if SDA is high */
188 if (bri
->get_sda
&& bri
->get_sda(adap
))
190 /* SCL shouldn't be low here */
191 if (!bri
->get_scl(adap
)) {
193 "SCL is stuck low, exit recovery\n");
200 bri
->set_scl(adap
, val
);
201 ndelay(RECOVERY_NDELAY
);
204 if (bri
->unprepare_recovery
)
205 bri
->unprepare_recovery(bri
);
210 int i2c_generic_scl_recovery(struct i2c_adapter
*adap
)
212 adap
->bus_recovery_info
->set_scl(adap
, 1);
213 return i2c_generic_recovery(adap
);
216 int i2c_generic_gpio_recovery(struct i2c_adapter
*adap
)
220 ret
= i2c_get_gpios_for_recovery(adap
);
224 ret
= i2c_generic_recovery(adap
);
225 i2c_put_gpios_for_recovery(adap
);
230 int i2c_recover_bus(struct i2c_adapter
*adap
)
232 if (!adap
->bus_recovery_info
)
235 dev_dbg(&adap
->dev
, "Trying i2c bus recovery\n");
236 return adap
->bus_recovery_info
->recover_bus(adap
);
239 static int i2c_device_probe(struct device
*dev
)
241 struct i2c_client
*client
= i2c_verify_client(dev
);
242 struct i2c_driver
*driver
;
248 driver
= to_i2c_driver(dev
->driver
);
249 if (!driver
->probe
|| !driver
->id_table
)
251 client
->driver
= driver
;
252 if (!device_can_wakeup(&client
->dev
))
253 device_init_wakeup(&client
->dev
,
254 client
->flags
& I2C_CLIENT_WAKE
);
255 dev_dbg(dev
, "probe\n");
257 status
= driver
->probe(client
, i2c_match_id(driver
->id_table
, client
));
259 client
->driver
= NULL
;
260 i2c_set_clientdata(client
, NULL
);
265 static int i2c_device_remove(struct device
*dev
)
267 struct i2c_client
*client
= i2c_verify_client(dev
);
268 struct i2c_driver
*driver
;
271 if (!client
|| !dev
->driver
)
274 driver
= to_i2c_driver(dev
->driver
);
275 if (driver
->remove
) {
276 dev_dbg(dev
, "remove\n");
277 status
= driver
->remove(client
);
283 client
->driver
= NULL
;
284 i2c_set_clientdata(client
, NULL
);
289 static void i2c_device_shutdown(struct device
*dev
)
291 struct i2c_client
*client
= i2c_verify_client(dev
);
292 struct i2c_driver
*driver
;
294 if (!client
|| !dev
->driver
)
296 driver
= to_i2c_driver(dev
->driver
);
297 if (driver
->shutdown
)
298 driver
->shutdown(client
);
301 #ifdef CONFIG_PM_SLEEP
302 static int i2c_legacy_suspend(struct device
*dev
, pm_message_t mesg
)
304 struct i2c_client
*client
= i2c_verify_client(dev
);
305 struct i2c_driver
*driver
;
307 if (!client
|| !dev
->driver
)
309 driver
= to_i2c_driver(dev
->driver
);
310 if (!driver
->suspend
)
312 return driver
->suspend(client
, mesg
);
315 static int i2c_legacy_resume(struct device
*dev
)
317 struct i2c_client
*client
= i2c_verify_client(dev
);
318 struct i2c_driver
*driver
;
320 if (!client
|| !dev
->driver
)
322 driver
= to_i2c_driver(dev
->driver
);
325 return driver
->resume(client
);
328 static int i2c_device_pm_suspend(struct device
*dev
)
330 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
333 return pm_generic_suspend(dev
);
335 return i2c_legacy_suspend(dev
, PMSG_SUSPEND
);
338 static int i2c_device_pm_resume(struct device
*dev
)
340 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
343 return pm_generic_resume(dev
);
345 return i2c_legacy_resume(dev
);
348 static int i2c_device_pm_freeze(struct device
*dev
)
350 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
353 return pm_generic_freeze(dev
);
355 return i2c_legacy_suspend(dev
, PMSG_FREEZE
);
358 static int i2c_device_pm_thaw(struct device
*dev
)
360 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
363 return pm_generic_thaw(dev
);
365 return i2c_legacy_resume(dev
);
368 static int i2c_device_pm_poweroff(struct device
*dev
)
370 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
373 return pm_generic_poweroff(dev
);
375 return i2c_legacy_suspend(dev
, PMSG_HIBERNATE
);
378 static int i2c_device_pm_restore(struct device
*dev
)
380 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
383 return pm_generic_restore(dev
);
385 return i2c_legacy_resume(dev
);
387 #else /* !CONFIG_PM_SLEEP */
388 #define i2c_device_pm_suspend NULL
389 #define i2c_device_pm_resume NULL
390 #define i2c_device_pm_freeze NULL
391 #define i2c_device_pm_thaw NULL
392 #define i2c_device_pm_poweroff NULL
393 #define i2c_device_pm_restore NULL
394 #endif /* !CONFIG_PM_SLEEP */
396 static void i2c_client_dev_release(struct device
*dev
)
398 kfree(to_i2c_client(dev
));
402 show_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
404 return sprintf(buf
, "%s\n", dev
->type
== &i2c_client_type
?
405 to_i2c_client(dev
)->name
: to_i2c_adapter(dev
)->name
);
409 show_modalias(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
411 struct i2c_client
*client
= to_i2c_client(dev
);
412 return sprintf(buf
, "%s%s\n", I2C_MODULE_PREFIX
, client
->name
);
415 static DEVICE_ATTR(name
, S_IRUGO
, show_name
, NULL
);
416 static DEVICE_ATTR(modalias
, S_IRUGO
, show_modalias
, NULL
);
418 static struct attribute
*i2c_dev_attrs
[] = {
420 /* modalias helps coldplug: modprobe $(cat .../modalias) */
421 &dev_attr_modalias
.attr
,
425 static struct attribute_group i2c_dev_attr_group
= {
426 .attrs
= i2c_dev_attrs
,
429 static const struct attribute_group
*i2c_dev_attr_groups
[] = {
434 static const struct dev_pm_ops i2c_device_pm_ops
= {
435 .suspend
= i2c_device_pm_suspend
,
436 .resume
= i2c_device_pm_resume
,
437 .freeze
= i2c_device_pm_freeze
,
438 .thaw
= i2c_device_pm_thaw
,
439 .poweroff
= i2c_device_pm_poweroff
,
440 .restore
= i2c_device_pm_restore
,
442 pm_generic_runtime_suspend
,
443 pm_generic_runtime_resume
,
448 struct bus_type i2c_bus_type
= {
450 .match
= i2c_device_match
,
451 .probe
= i2c_device_probe
,
452 .remove
= i2c_device_remove
,
453 .shutdown
= i2c_device_shutdown
,
454 .pm
= &i2c_device_pm_ops
,
456 EXPORT_SYMBOL_GPL(i2c_bus_type
);
458 static struct device_type i2c_client_type
= {
459 .groups
= i2c_dev_attr_groups
,
460 .uevent
= i2c_device_uevent
,
461 .release
= i2c_client_dev_release
,
466 * i2c_verify_client - return parameter as i2c_client, or NULL
467 * @dev: device, probably from some driver model iterator
469 * When traversing the driver model tree, perhaps using driver model
470 * iterators like @device_for_each_child(), you can't assume very much
471 * about the nodes you find. Use this function to avoid oopses caused
472 * by wrongly treating some non-I2C device as an i2c_client.
474 struct i2c_client
*i2c_verify_client(struct device
*dev
)
476 return (dev
->type
== &i2c_client_type
)
480 EXPORT_SYMBOL(i2c_verify_client
);
483 /* This is a permissive address validity check, I2C address map constraints
484 * are purposely not enforced, except for the general call address. */
485 static int i2c_check_client_addr_validity(const struct i2c_client
*client
)
487 if (client
->flags
& I2C_CLIENT_TEN
) {
488 /* 10-bit address, all values are valid */
489 if (client
->addr
> 0x3ff)
492 /* 7-bit address, reject the general call address */
493 if (client
->addr
== 0x00 || client
->addr
> 0x7f)
499 /* And this is a strict address validity check, used when probing. If a
500 * device uses a reserved address, then it shouldn't be probed. 7-bit
501 * addressing is assumed, 10-bit address devices are rare and should be
502 * explicitly enumerated. */
503 static int i2c_check_addr_validity(unsigned short addr
)
506 * Reserved addresses per I2C specification:
507 * 0x00 General call address / START byte
509 * 0x02 Reserved for different bus format
510 * 0x03 Reserved for future purposes
511 * 0x04-0x07 Hs-mode master code
512 * 0x78-0x7b 10-bit slave addressing
513 * 0x7c-0x7f Reserved for future purposes
515 if (addr
< 0x08 || addr
> 0x77)
520 static int __i2c_check_addr_busy(struct device
*dev
, void *addrp
)
522 struct i2c_client
*client
= i2c_verify_client(dev
);
523 int addr
= *(int *)addrp
;
525 if (client
&& client
->addr
== addr
)
530 /* walk up mux tree */
531 static int i2c_check_mux_parents(struct i2c_adapter
*adapter
, int addr
)
533 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
536 result
= device_for_each_child(&adapter
->dev
, &addr
,
537 __i2c_check_addr_busy
);
539 if (!result
&& parent
)
540 result
= i2c_check_mux_parents(parent
, addr
);
545 /* recurse down mux tree */
546 static int i2c_check_mux_children(struct device
*dev
, void *addrp
)
550 if (dev
->type
== &i2c_adapter_type
)
551 result
= device_for_each_child(dev
, addrp
,
552 i2c_check_mux_children
);
554 result
= __i2c_check_addr_busy(dev
, addrp
);
559 static int i2c_check_addr_busy(struct i2c_adapter
*adapter
, int addr
)
561 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
565 result
= i2c_check_mux_parents(parent
, addr
);
568 result
= device_for_each_child(&adapter
->dev
, &addr
,
569 i2c_check_mux_children
);
575 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
576 * @adapter: Target I2C bus segment
578 void i2c_lock_adapter(struct i2c_adapter
*adapter
)
580 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
583 i2c_lock_adapter(parent
);
585 rt_mutex_lock(&adapter
->bus_lock
);
587 EXPORT_SYMBOL_GPL(i2c_lock_adapter
);
590 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
591 * @adapter: Target I2C bus segment
593 static int i2c_trylock_adapter(struct i2c_adapter
*adapter
)
595 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
598 return i2c_trylock_adapter(parent
);
600 return rt_mutex_trylock(&adapter
->bus_lock
);
604 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
605 * @adapter: Target I2C bus segment
607 void i2c_unlock_adapter(struct i2c_adapter
*adapter
)
609 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
612 i2c_unlock_adapter(parent
);
614 rt_mutex_unlock(&adapter
->bus_lock
);
616 EXPORT_SYMBOL_GPL(i2c_unlock_adapter
);
619 * i2c_new_device - instantiate an i2c device
620 * @adap: the adapter managing the device
621 * @info: describes one I2C device; bus_num is ignored
624 * Create an i2c device. Binding is handled through driver model
625 * probe()/remove() methods. A driver may be bound to this device when we
626 * return from this function, or any later moment (e.g. maybe hotplugging will
627 * load the driver module). This call is not appropriate for use by mainboard
628 * initialization logic, which usually runs during an arch_initcall() long
629 * before any i2c_adapter could exist.
631 * This returns the new i2c client, which may be saved for later use with
632 * i2c_unregister_device(); or NULL to indicate an error.
635 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
)
637 struct i2c_client
*client
;
640 client
= kzalloc(sizeof *client
, GFP_KERNEL
);
644 client
->adapter
= adap
;
646 client
->dev
.platform_data
= info
->platform_data
;
649 client
->dev
.archdata
= *info
->archdata
;
651 client
->flags
= info
->flags
;
652 client
->addr
= info
->addr
;
653 client
->irq
= info
->irq
;
655 strlcpy(client
->name
, info
->type
, sizeof(client
->name
));
657 /* Check for address validity */
658 status
= i2c_check_client_addr_validity(client
);
660 dev_err(&adap
->dev
, "Invalid %d-bit I2C address 0x%02hx\n",
661 client
->flags
& I2C_CLIENT_TEN
? 10 : 7, client
->addr
);
665 /* Check for address business */
666 status
= i2c_check_addr_busy(adap
, client
->addr
);
670 client
->dev
.parent
= &client
->adapter
->dev
;
671 client
->dev
.bus
= &i2c_bus_type
;
672 client
->dev
.type
= &i2c_client_type
;
673 client
->dev
.of_node
= info
->of_node
;
674 ACPI_HANDLE_SET(&client
->dev
, info
->acpi_node
.handle
);
676 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
677 dev_set_name(&client
->dev
, "%d-%04x", i2c_adapter_id(adap
),
678 client
->addr
| ((client
->flags
& I2C_CLIENT_TEN
)
680 status
= device_register(&client
->dev
);
684 dev_dbg(&adap
->dev
, "client [%s] registered with bus id %s\n",
685 client
->name
, dev_name(&client
->dev
));
690 dev_err(&adap
->dev
, "Failed to register i2c client %s at 0x%02x "
691 "(%d)\n", client
->name
, client
->addr
, status
);
696 EXPORT_SYMBOL_GPL(i2c_new_device
);
700 * i2c_unregister_device - reverse effect of i2c_new_device()
701 * @client: value returned from i2c_new_device()
704 void i2c_unregister_device(struct i2c_client
*client
)
706 device_unregister(&client
->dev
);
708 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
711 static const struct i2c_device_id dummy_id
[] = {
716 static int dummy_probe(struct i2c_client
*client
,
717 const struct i2c_device_id
*id
)
722 static int dummy_remove(struct i2c_client
*client
)
727 static struct i2c_driver dummy_driver
= {
728 .driver
.name
= "dummy",
729 .probe
= dummy_probe
,
730 .remove
= dummy_remove
,
731 .id_table
= dummy_id
,
735 * i2c_new_dummy - return a new i2c device bound to a dummy driver
736 * @adapter: the adapter managing the device
737 * @address: seven bit address to be used
740 * This returns an I2C client bound to the "dummy" driver, intended for use
741 * with devices that consume multiple addresses. Examples of such chips
742 * include various EEPROMS (like 24c04 and 24c08 models).
744 * These dummy devices have two main uses. First, most I2C and SMBus calls
745 * except i2c_transfer() need a client handle; the dummy will be that handle.
746 * And second, this prevents the specified address from being bound to a
749 * This returns the new i2c client, which should be saved for later use with
750 * i2c_unregister_device(); or NULL to indicate an error.
752 struct i2c_client
*i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
754 struct i2c_board_info info
= {
755 I2C_BOARD_INFO("dummy", address
),
758 return i2c_new_device(adapter
, &info
);
760 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
762 /* ------------------------------------------------------------------------- */
764 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
766 static void i2c_adapter_dev_release(struct device
*dev
)
768 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
769 complete(&adap
->dev_released
);
773 * This function is only needed for mutex_lock_nested, so it is never
774 * called unless locking correctness checking is enabled. Thus we
775 * make it inline to avoid a compiler warning. That's what gcc ends up
778 static inline unsigned int i2c_adapter_depth(struct i2c_adapter
*adapter
)
780 unsigned int depth
= 0;
782 while ((adapter
= i2c_parent_is_i2c_adapter(adapter
)))
789 * Let users instantiate I2C devices through sysfs. This can be used when
790 * platform initialization code doesn't contain the proper data for
791 * whatever reason. Also useful for drivers that do device detection and
792 * detection fails, either because the device uses an unexpected address,
793 * or this is a compatible device with different ID register values.
795 * Parameter checking may look overzealous, but we really don't want
796 * the user to provide incorrect parameters.
799 i2c_sysfs_new_device(struct device
*dev
, struct device_attribute
*attr
,
800 const char *buf
, size_t count
)
802 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
803 struct i2c_board_info info
;
804 struct i2c_client
*client
;
808 memset(&info
, 0, sizeof(struct i2c_board_info
));
810 blank
= strchr(buf
, ' ');
812 dev_err(dev
, "%s: Missing parameters\n", "new_device");
815 if (blank
- buf
> I2C_NAME_SIZE
- 1) {
816 dev_err(dev
, "%s: Invalid device name\n", "new_device");
819 memcpy(info
.type
, buf
, blank
- buf
);
821 /* Parse remaining parameters, reject extra parameters */
822 res
= sscanf(++blank
, "%hi%c", &info
.addr
, &end
);
824 dev_err(dev
, "%s: Can't parse I2C address\n", "new_device");
827 if (res
> 1 && end
!= '\n') {
828 dev_err(dev
, "%s: Extra parameters\n", "new_device");
832 client
= i2c_new_device(adap
, &info
);
836 /* Keep track of the added device */
837 mutex_lock(&adap
->userspace_clients_lock
);
838 list_add_tail(&client
->detected
, &adap
->userspace_clients
);
839 mutex_unlock(&adap
->userspace_clients_lock
);
840 dev_info(dev
, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
841 info
.type
, info
.addr
);
847 * And of course let the users delete the devices they instantiated, if
848 * they got it wrong. This interface can only be used to delete devices
849 * instantiated by i2c_sysfs_new_device above. This guarantees that we
850 * don't delete devices to which some kernel code still has references.
852 * Parameter checking may look overzealous, but we really don't want
853 * the user to delete the wrong device.
856 i2c_sysfs_delete_device(struct device
*dev
, struct device_attribute
*attr
,
857 const char *buf
, size_t count
)
859 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
860 struct i2c_client
*client
, *next
;
865 /* Parse parameters, reject extra parameters */
866 res
= sscanf(buf
, "%hi%c", &addr
, &end
);
868 dev_err(dev
, "%s: Can't parse I2C address\n", "delete_device");
871 if (res
> 1 && end
!= '\n') {
872 dev_err(dev
, "%s: Extra parameters\n", "delete_device");
876 /* Make sure the device was added through sysfs */
878 mutex_lock_nested(&adap
->userspace_clients_lock
,
879 i2c_adapter_depth(adap
));
880 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
882 if (client
->addr
== addr
) {
883 dev_info(dev
, "%s: Deleting device %s at 0x%02hx\n",
884 "delete_device", client
->name
, client
->addr
);
886 list_del(&client
->detected
);
887 i2c_unregister_device(client
);
892 mutex_unlock(&adap
->userspace_clients_lock
);
895 dev_err(dev
, "%s: Can't find device in list\n",
900 static DEVICE_ATTR(new_device
, S_IWUSR
, NULL
, i2c_sysfs_new_device
);
901 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device
, S_IWUSR
, NULL
,
902 i2c_sysfs_delete_device
);
904 static struct attribute
*i2c_adapter_attrs
[] = {
906 &dev_attr_new_device
.attr
,
907 &dev_attr_delete_device
.attr
,
911 static struct attribute_group i2c_adapter_attr_group
= {
912 .attrs
= i2c_adapter_attrs
,
915 static const struct attribute_group
*i2c_adapter_attr_groups
[] = {
916 &i2c_adapter_attr_group
,
920 struct device_type i2c_adapter_type
= {
921 .groups
= i2c_adapter_attr_groups
,
922 .release
= i2c_adapter_dev_release
,
924 EXPORT_SYMBOL_GPL(i2c_adapter_type
);
927 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
928 * @dev: device, probably from some driver model iterator
930 * When traversing the driver model tree, perhaps using driver model
931 * iterators like @device_for_each_child(), you can't assume very much
932 * about the nodes you find. Use this function to avoid oopses caused
933 * by wrongly treating some non-I2C device as an i2c_adapter.
935 struct i2c_adapter
*i2c_verify_adapter(struct device
*dev
)
937 return (dev
->type
== &i2c_adapter_type
)
938 ? to_i2c_adapter(dev
)
941 EXPORT_SYMBOL(i2c_verify_adapter
);
943 #ifdef CONFIG_I2C_COMPAT
944 static struct class_compat
*i2c_adapter_compat_class
;
947 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
949 struct i2c_devinfo
*devinfo
;
951 down_read(&__i2c_board_lock
);
952 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
953 if (devinfo
->busnum
== adapter
->nr
954 && !i2c_new_device(adapter
,
955 &devinfo
->board_info
))
956 dev_err(&adapter
->dev
,
957 "Can't create device at 0x%02x\n",
958 devinfo
->board_info
.addr
);
960 up_read(&__i2c_board_lock
);
963 /* OF support code */
965 #if IS_ENABLED(CONFIG_OF)
966 static void of_i2c_register_devices(struct i2c_adapter
*adap
)
969 struct device_node
*node
;
971 /* Only register child devices if the adapter has a node pointer set */
972 if (!adap
->dev
.of_node
)
975 dev_dbg(&adap
->dev
, "of_i2c: walking child nodes\n");
977 for_each_available_child_of_node(adap
->dev
.of_node
, node
) {
978 struct i2c_board_info info
= {};
979 struct dev_archdata dev_ad
= {};
983 dev_dbg(&adap
->dev
, "of_i2c: register %s\n", node
->full_name
);
985 if (of_modalias_node(node
, info
.type
, sizeof(info
.type
)) < 0) {
986 dev_err(&adap
->dev
, "of_i2c: modalias failure on %s\n",
991 addr
= of_get_property(node
, "reg", &len
);
992 if (!addr
|| (len
< sizeof(int))) {
993 dev_err(&adap
->dev
, "of_i2c: invalid reg on %s\n",
998 info
.addr
= be32_to_cpup(addr
);
999 if (info
.addr
> (1 << 10) - 1) {
1000 dev_err(&adap
->dev
, "of_i2c: invalid addr=%x on %s\n",
1001 info
.addr
, node
->full_name
);
1005 info
.irq
= irq_of_parse_and_map(node
, 0);
1006 info
.of_node
= of_node_get(node
);
1007 info
.archdata
= &dev_ad
;
1009 if (of_get_property(node
, "wakeup-source", NULL
))
1010 info
.flags
|= I2C_CLIENT_WAKE
;
1012 request_module("%s%s", I2C_MODULE_PREFIX
, info
.type
);
1014 result
= i2c_new_device(adap
, &info
);
1015 if (result
== NULL
) {
1016 dev_err(&adap
->dev
, "of_i2c: Failure registering %s\n",
1019 irq_dispose_mapping(info
.irq
);
1025 static int of_dev_node_match(struct device
*dev
, void *data
)
1027 return dev
->of_node
== data
;
1030 /* must call put_device() when done with returned i2c_client device */
1031 struct i2c_client
*of_find_i2c_device_by_node(struct device_node
*node
)
1035 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1040 return i2c_verify_client(dev
);
1042 EXPORT_SYMBOL(of_find_i2c_device_by_node
);
1044 /* must call put_device() when done with returned i2c_adapter device */
1045 struct i2c_adapter
*of_find_i2c_adapter_by_node(struct device_node
*node
)
1049 dev
= bus_find_device(&i2c_bus_type
, NULL
, node
,
1054 return i2c_verify_adapter(dev
);
1056 EXPORT_SYMBOL(of_find_i2c_adapter_by_node
);
1058 static void of_i2c_register_devices(struct i2c_adapter
*adap
) { }
1059 #endif /* CONFIG_OF */
1061 static int i2c_do_add_adapter(struct i2c_driver
*driver
,
1062 struct i2c_adapter
*adap
)
1064 /* Detect supported devices on that bus, and instantiate them */
1065 i2c_detect(adap
, driver
);
1067 /* Let legacy drivers scan this bus for matching devices */
1068 if (driver
->attach_adapter
) {
1069 dev_warn(&adap
->dev
, "%s: attach_adapter method is deprecated\n",
1070 driver
->driver
.name
);
1071 dev_warn(&adap
->dev
, "Please use another way to instantiate "
1072 "your i2c_client\n");
1073 /* We ignore the return code; if it fails, too bad */
1074 driver
->attach_adapter(adap
);
1079 static int __process_new_adapter(struct device_driver
*d
, void *data
)
1081 return i2c_do_add_adapter(to_i2c_driver(d
), data
);
1084 static int i2c_register_adapter(struct i2c_adapter
*adap
)
1088 /* Can't register until after driver model init */
1089 if (unlikely(WARN_ON(!i2c_bus_type
.p
))) {
1095 if (unlikely(adap
->name
[0] == '\0')) {
1096 pr_err("i2c-core: Attempt to register an adapter with "
1100 if (unlikely(!adap
->algo
)) {
1101 pr_err("i2c-core: Attempt to register adapter '%s' with "
1102 "no algo!\n", adap
->name
);
1106 rt_mutex_init(&adap
->bus_lock
);
1107 mutex_init(&adap
->userspace_clients_lock
);
1108 INIT_LIST_HEAD(&adap
->userspace_clients
);
1110 /* Set default timeout to 1 second if not already set */
1111 if (adap
->timeout
== 0)
1114 dev_set_name(&adap
->dev
, "i2c-%d", adap
->nr
);
1115 adap
->dev
.bus
= &i2c_bus_type
;
1116 adap
->dev
.type
= &i2c_adapter_type
;
1117 res
= device_register(&adap
->dev
);
1121 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
1123 #ifdef CONFIG_I2C_COMPAT
1124 res
= class_compat_create_link(i2c_adapter_compat_class
, &adap
->dev
,
1127 dev_warn(&adap
->dev
,
1128 "Failed to create compatibility class link\n");
1131 /* bus recovery specific initialization */
1132 if (adap
->bus_recovery_info
) {
1133 struct i2c_bus_recovery_info
*bri
= adap
->bus_recovery_info
;
1135 if (!bri
->recover_bus
) {
1136 dev_err(&adap
->dev
, "No recover_bus() found, not using recovery\n");
1137 adap
->bus_recovery_info
= NULL
;
1141 /* Generic GPIO recovery */
1142 if (bri
->recover_bus
== i2c_generic_gpio_recovery
) {
1143 if (!gpio_is_valid(bri
->scl_gpio
)) {
1144 dev_err(&adap
->dev
, "Invalid SCL gpio, not using recovery\n");
1145 adap
->bus_recovery_info
= NULL
;
1149 if (gpio_is_valid(bri
->sda_gpio
))
1150 bri
->get_sda
= get_sda_gpio_value
;
1152 bri
->get_sda
= NULL
;
1154 bri
->get_scl
= get_scl_gpio_value
;
1155 bri
->set_scl
= set_scl_gpio_value
;
1156 } else if (!bri
->set_scl
|| !bri
->get_scl
) {
1157 /* Generic SCL recovery */
1158 dev_err(&adap
->dev
, "No {get|set}_gpio() found, not using recovery\n");
1159 adap
->bus_recovery_info
= NULL
;
1164 /* create pre-declared device nodes */
1165 of_i2c_register_devices(adap
);
1167 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
1168 i2c_scan_static_board_info(adap
);
1170 /* Notify drivers */
1171 mutex_lock(&core_lock
);
1172 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
, __process_new_adapter
);
1173 mutex_unlock(&core_lock
);
1178 mutex_lock(&core_lock
);
1179 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1180 mutex_unlock(&core_lock
);
1185 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1186 * @adap: the adapter to register (with adap->nr initialized)
1187 * Context: can sleep
1189 * See i2c_add_numbered_adapter() for details.
1191 static int __i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1195 mutex_lock(&core_lock
);
1196 id
= idr_alloc(&i2c_adapter_idr
, adap
, adap
->nr
, adap
->nr
+ 1,
1198 mutex_unlock(&core_lock
);
1200 return id
== -ENOSPC
? -EBUSY
: id
;
1202 return i2c_register_adapter(adap
);
1206 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1207 * @adapter: the adapter to add
1208 * Context: can sleep
1210 * This routine is used to declare an I2C adapter when its bus number
1211 * doesn't matter or when its bus number is specified by an dt alias.
1212 * Examples of bases when the bus number doesn't matter: I2C adapters
1213 * dynamically added by USB links or PCI plugin cards.
1215 * When this returns zero, a new bus number was allocated and stored
1216 * in adap->nr, and the specified adapter became available for clients.
1217 * Otherwise, a negative errno value is returned.
1219 int i2c_add_adapter(struct i2c_adapter
*adapter
)
1221 struct device
*dev
= &adapter
->dev
;
1225 id
= of_alias_get_id(dev
->of_node
, "i2c");
1228 return __i2c_add_numbered_adapter(adapter
);
1232 mutex_lock(&core_lock
);
1233 id
= idr_alloc(&i2c_adapter_idr
, adapter
,
1234 __i2c_first_dynamic_bus_num
, 0, GFP_KERNEL
);
1235 mutex_unlock(&core_lock
);
1241 return i2c_register_adapter(adapter
);
1243 EXPORT_SYMBOL(i2c_add_adapter
);
1246 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1247 * @adap: the adapter to register (with adap->nr initialized)
1248 * Context: can sleep
1250 * This routine is used to declare an I2C adapter when its bus number
1251 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1252 * or otherwise built in to the system's mainboard, and where i2c_board_info
1253 * is used to properly configure I2C devices.
1255 * If the requested bus number is set to -1, then this function will behave
1256 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1258 * If no devices have pre-been declared for this bus, then be sure to
1259 * register the adapter before any dynamically allocated ones. Otherwise
1260 * the required bus ID may not be available.
1262 * When this returns zero, the specified adapter became available for
1263 * clients using the bus number provided in adap->nr. Also, the table
1264 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1265 * and the appropriate driver model device nodes are created. Otherwise, a
1266 * negative errno value is returned.
1268 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
1270 if (adap
->nr
== -1) /* -1 means dynamically assign bus id */
1271 return i2c_add_adapter(adap
);
1273 return __i2c_add_numbered_adapter(adap
);
1275 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
1277 static void i2c_do_del_adapter(struct i2c_driver
*driver
,
1278 struct i2c_adapter
*adapter
)
1280 struct i2c_client
*client
, *_n
;
1282 /* Remove the devices we created ourselves as the result of hardware
1283 * probing (using a driver's detect method) */
1284 list_for_each_entry_safe(client
, _n
, &driver
->clients
, detected
) {
1285 if (client
->adapter
== adapter
) {
1286 dev_dbg(&adapter
->dev
, "Removing %s at 0x%x\n",
1287 client
->name
, client
->addr
);
1288 list_del(&client
->detected
);
1289 i2c_unregister_device(client
);
1294 static int __unregister_client(struct device
*dev
, void *dummy
)
1296 struct i2c_client
*client
= i2c_verify_client(dev
);
1297 if (client
&& strcmp(client
->name
, "dummy"))
1298 i2c_unregister_device(client
);
1302 static int __unregister_dummy(struct device
*dev
, void *dummy
)
1304 struct i2c_client
*client
= i2c_verify_client(dev
);
1306 i2c_unregister_device(client
);
1310 static int __process_removed_adapter(struct device_driver
*d
, void *data
)
1312 i2c_do_del_adapter(to_i2c_driver(d
), data
);
1317 * i2c_del_adapter - unregister I2C adapter
1318 * @adap: the adapter being unregistered
1319 * Context: can sleep
1321 * This unregisters an I2C adapter which was previously registered
1322 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1324 void i2c_del_adapter(struct i2c_adapter
*adap
)
1326 struct i2c_adapter
*found
;
1327 struct i2c_client
*client
, *next
;
1329 /* First make sure that this adapter was ever added */
1330 mutex_lock(&core_lock
);
1331 found
= idr_find(&i2c_adapter_idr
, adap
->nr
);
1332 mutex_unlock(&core_lock
);
1333 if (found
!= adap
) {
1334 pr_debug("i2c-core: attempting to delete unregistered "
1335 "adapter [%s]\n", adap
->name
);
1339 /* Tell drivers about this removal */
1340 mutex_lock(&core_lock
);
1341 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
1342 __process_removed_adapter
);
1343 mutex_unlock(&core_lock
);
1345 /* Remove devices instantiated from sysfs */
1346 mutex_lock_nested(&adap
->userspace_clients_lock
,
1347 i2c_adapter_depth(adap
));
1348 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1350 dev_dbg(&adap
->dev
, "Removing %s at 0x%x\n", client
->name
,
1352 list_del(&client
->detected
);
1353 i2c_unregister_device(client
);
1355 mutex_unlock(&adap
->userspace_clients_lock
);
1357 /* Detach any active clients. This can't fail, thus we do not
1358 * check the returned value. This is a two-pass process, because
1359 * we can't remove the dummy devices during the first pass: they
1360 * could have been instantiated by real devices wishing to clean
1361 * them up properly, so we give them a chance to do that first. */
1362 device_for_each_child(&adap
->dev
, NULL
, __unregister_client
);
1363 device_for_each_child(&adap
->dev
, NULL
, __unregister_dummy
);
1365 #ifdef CONFIG_I2C_COMPAT
1366 class_compat_remove_link(i2c_adapter_compat_class
, &adap
->dev
,
1370 /* device name is gone after device_unregister */
1371 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
1373 /* clean up the sysfs representation */
1374 init_completion(&adap
->dev_released
);
1375 device_unregister(&adap
->dev
);
1377 /* wait for sysfs to drop all references */
1378 wait_for_completion(&adap
->dev_released
);
1381 mutex_lock(&core_lock
);
1382 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1383 mutex_unlock(&core_lock
);
1385 /* Clear the device structure in case this adapter is ever going to be
1387 memset(&adap
->dev
, 0, sizeof(adap
->dev
));
1389 EXPORT_SYMBOL(i2c_del_adapter
);
1391 /* ------------------------------------------------------------------------- */
1393 int i2c_for_each_dev(void *data
, int (*fn
)(struct device
*, void *))
1397 mutex_lock(&core_lock
);
1398 res
= bus_for_each_dev(&i2c_bus_type
, NULL
, data
, fn
);
1399 mutex_unlock(&core_lock
);
1403 EXPORT_SYMBOL_GPL(i2c_for_each_dev
);
1405 static int __process_new_driver(struct device
*dev
, void *data
)
1407 if (dev
->type
!= &i2c_adapter_type
)
1409 return i2c_do_add_adapter(data
, to_i2c_adapter(dev
));
1413 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1414 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1417 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
1421 /* Can't register until after driver model init */
1422 if (unlikely(WARN_ON(!i2c_bus_type
.p
)))
1425 /* add the driver to the list of i2c drivers in the driver core */
1426 driver
->driver
.owner
= owner
;
1427 driver
->driver
.bus
= &i2c_bus_type
;
1429 /* When registration returns, the driver core
1430 * will have called probe() for all matching-but-unbound devices.
1432 res
= driver_register(&driver
->driver
);
1436 /* Drivers should switch to dev_pm_ops instead. */
1437 if (driver
->suspend
)
1438 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1439 driver
->driver
.name
);
1441 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1442 driver
->driver
.name
);
1444 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
1446 INIT_LIST_HEAD(&driver
->clients
);
1447 /* Walk the adapters that are already present */
1448 i2c_for_each_dev(driver
, __process_new_driver
);
1452 EXPORT_SYMBOL(i2c_register_driver
);
1454 static int __process_removed_driver(struct device
*dev
, void *data
)
1456 if (dev
->type
== &i2c_adapter_type
)
1457 i2c_do_del_adapter(data
, to_i2c_adapter(dev
));
1462 * i2c_del_driver - unregister I2C driver
1463 * @driver: the driver being unregistered
1464 * Context: can sleep
1466 void i2c_del_driver(struct i2c_driver
*driver
)
1468 i2c_for_each_dev(driver
, __process_removed_driver
);
1470 driver_unregister(&driver
->driver
);
1471 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
1473 EXPORT_SYMBOL(i2c_del_driver
);
1475 /* ------------------------------------------------------------------------- */
1478 * i2c_use_client - increments the reference count of the i2c client structure
1479 * @client: the client being referenced
1481 * Each live reference to a client should be refcounted. The driver model does
1482 * that automatically as part of driver binding, so that most drivers don't
1483 * need to do this explicitly: they hold a reference until they're unbound
1486 * A pointer to the client with the incremented reference counter is returned.
1488 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
1490 if (client
&& get_device(&client
->dev
))
1494 EXPORT_SYMBOL(i2c_use_client
);
1497 * i2c_release_client - release a use of the i2c client structure
1498 * @client: the client being no longer referenced
1500 * Must be called when a user of a client is finished with it.
1502 void i2c_release_client(struct i2c_client
*client
)
1505 put_device(&client
->dev
);
1507 EXPORT_SYMBOL(i2c_release_client
);
1509 struct i2c_cmd_arg
{
1514 static int i2c_cmd(struct device
*dev
, void *_arg
)
1516 struct i2c_client
*client
= i2c_verify_client(dev
);
1517 struct i2c_cmd_arg
*arg
= _arg
;
1519 if (client
&& client
->driver
&& client
->driver
->command
)
1520 client
->driver
->command(client
, arg
->cmd
, arg
->arg
);
1524 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
1526 struct i2c_cmd_arg cmd_arg
;
1530 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
1532 EXPORT_SYMBOL(i2c_clients_command
);
1534 static int __init
i2c_init(void)
1538 retval
= bus_register(&i2c_bus_type
);
1541 #ifdef CONFIG_I2C_COMPAT
1542 i2c_adapter_compat_class
= class_compat_register("i2c-adapter");
1543 if (!i2c_adapter_compat_class
) {
1548 retval
= i2c_add_driver(&dummy_driver
);
1554 #ifdef CONFIG_I2C_COMPAT
1555 class_compat_unregister(i2c_adapter_compat_class
);
1558 bus_unregister(&i2c_bus_type
);
1562 static void __exit
i2c_exit(void)
1564 i2c_del_driver(&dummy_driver
);
1565 #ifdef CONFIG_I2C_COMPAT
1566 class_compat_unregister(i2c_adapter_compat_class
);
1568 bus_unregister(&i2c_bus_type
);
1571 /* We must initialize early, because some subsystems register i2c drivers
1572 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1574 postcore_initcall(i2c_init
);
1575 module_exit(i2c_exit
);
1577 /* ----------------------------------------------------
1578 * the functional interface to the i2c busses.
1579 * ----------------------------------------------------
1583 * __i2c_transfer - unlocked flavor of i2c_transfer
1584 * @adap: Handle to I2C bus
1585 * @msgs: One or more messages to execute before STOP is issued to
1586 * terminate the operation; each message begins with a START.
1587 * @num: Number of messages to be executed.
1589 * Returns negative errno, else the number of messages executed.
1591 * Adapter lock must be held when calling this function. No debug logging
1592 * takes place. adap->algo->master_xfer existence isn't checked.
1594 int __i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1596 unsigned long orig_jiffies
;
1599 /* Retry automatically on arbitration loss */
1600 orig_jiffies
= jiffies
;
1601 for (ret
= 0, try = 0; try <= adap
->retries
; try++) {
1602 ret
= adap
->algo
->master_xfer(adap
, msgs
, num
);
1605 if (time_after(jiffies
, orig_jiffies
+ adap
->timeout
))
1611 EXPORT_SYMBOL(__i2c_transfer
);
1614 * i2c_transfer - execute a single or combined I2C message
1615 * @adap: Handle to I2C bus
1616 * @msgs: One or more messages to execute before STOP is issued to
1617 * terminate the operation; each message begins with a START.
1618 * @num: Number of messages to be executed.
1620 * Returns negative errno, else the number of messages executed.
1622 * Note that there is no requirement that each message be sent to
1623 * the same slave address, although that is the most common model.
1625 int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1629 /* REVISIT the fault reporting model here is weak:
1631 * - When we get an error after receiving N bytes from a slave,
1632 * there is no way to report "N".
1634 * - When we get a NAK after transmitting N bytes to a slave,
1635 * there is no way to report "N" ... or to let the master
1636 * continue executing the rest of this combined message, if
1637 * that's the appropriate response.
1639 * - When for example "num" is two and we successfully complete
1640 * the first message but get an error part way through the
1641 * second, it's unclear whether that should be reported as
1642 * one (discarding status on the second message) or errno
1643 * (discarding status on the first one).
1646 if (adap
->algo
->master_xfer
) {
1648 for (ret
= 0; ret
< num
; ret
++) {
1649 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
1650 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
1651 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
1652 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
1656 if (in_atomic() || irqs_disabled()) {
1657 ret
= i2c_trylock_adapter(adap
);
1659 /* I2C activity is ongoing. */
1662 i2c_lock_adapter(adap
);
1665 ret
= __i2c_transfer(adap
, msgs
, num
);
1666 i2c_unlock_adapter(adap
);
1670 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
1674 EXPORT_SYMBOL(i2c_transfer
);
1677 * i2c_master_send - issue a single I2C message in master transmit mode
1678 * @client: Handle to slave device
1679 * @buf: Data that will be written to the slave
1680 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1682 * Returns negative errno, or else the number of bytes written.
1684 int i2c_master_send(const struct i2c_client
*client
, const char *buf
, int count
)
1687 struct i2c_adapter
*adap
= client
->adapter
;
1690 msg
.addr
= client
->addr
;
1691 msg
.flags
= client
->flags
& I2C_M_TEN
;
1693 msg
.buf
= (char *)buf
;
1695 ret
= i2c_transfer(adap
, &msg
, 1);
1698 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1699 * transmitted, else error code.
1701 return (ret
== 1) ? count
: ret
;
1703 EXPORT_SYMBOL(i2c_master_send
);
1706 * i2c_master_recv - issue a single I2C message in master receive mode
1707 * @client: Handle to slave device
1708 * @buf: Where to store data read from slave
1709 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1711 * Returns negative errno, or else the number of bytes read.
1713 int i2c_master_recv(const struct i2c_client
*client
, char *buf
, int count
)
1715 struct i2c_adapter
*adap
= client
->adapter
;
1719 msg
.addr
= client
->addr
;
1720 msg
.flags
= client
->flags
& I2C_M_TEN
;
1721 msg
.flags
|= I2C_M_RD
;
1725 ret
= i2c_transfer(adap
, &msg
, 1);
1728 * If everything went ok (i.e. 1 msg received), return #bytes received,
1731 return (ret
== 1) ? count
: ret
;
1733 EXPORT_SYMBOL(i2c_master_recv
);
1735 /* ----------------------------------------------------
1736 * the i2c address scanning function
1737 * Will not work for 10-bit addresses!
1738 * ----------------------------------------------------
1742 * Legacy default probe function, mostly relevant for SMBus. The default
1743 * probe method is a quick write, but it is known to corrupt the 24RF08
1744 * EEPROMs due to a state machine bug, and could also irreversibly
1745 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1746 * we use a short byte read instead. Also, some bus drivers don't implement
1747 * quick write, so we fallback to a byte read in that case too.
1748 * On x86, there is another special case for FSC hardware monitoring chips,
1749 * which want regular byte reads (address 0x73.) Fortunately, these are the
1750 * only known chips using this I2C address on PC hardware.
1751 * Returns 1 if probe succeeded, 0 if not.
1753 static int i2c_default_probe(struct i2c_adapter
*adap
, unsigned short addr
)
1756 union i2c_smbus_data dummy
;
1759 if (addr
== 0x73 && (adap
->class & I2C_CLASS_HWMON
)
1760 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
1761 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
1762 I2C_SMBUS_BYTE_DATA
, &dummy
);
1765 if (!((addr
& ~0x07) == 0x30 || (addr
& ~0x0f) == 0x50)
1766 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
))
1767 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_WRITE
, 0,
1768 I2C_SMBUS_QUICK
, NULL
);
1769 else if (i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
))
1770 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
1771 I2C_SMBUS_BYTE
, &dummy
);
1773 dev_warn(&adap
->dev
, "No suitable probing method supported for address 0x%02X\n",
1781 static int i2c_detect_address(struct i2c_client
*temp_client
,
1782 struct i2c_driver
*driver
)
1784 struct i2c_board_info info
;
1785 struct i2c_adapter
*adapter
= temp_client
->adapter
;
1786 int addr
= temp_client
->addr
;
1789 /* Make sure the address is valid */
1790 err
= i2c_check_addr_validity(addr
);
1792 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
1797 /* Skip if already in use */
1798 if (i2c_check_addr_busy(adapter
, addr
))
1801 /* Make sure there is something at this address */
1802 if (!i2c_default_probe(adapter
, addr
))
1805 /* Finally call the custom detection function */
1806 memset(&info
, 0, sizeof(struct i2c_board_info
));
1808 err
= driver
->detect(temp_client
, &info
);
1810 /* -ENODEV is returned if the detection fails. We catch it
1811 here as this isn't an error. */
1812 return err
== -ENODEV
? 0 : err
;
1815 /* Consistency check */
1816 if (info
.type
[0] == '\0') {
1817 dev_err(&adapter
->dev
, "%s detection function provided "
1818 "no name for 0x%x\n", driver
->driver
.name
,
1821 struct i2c_client
*client
;
1823 /* Detection succeeded, instantiate the device */
1824 dev_dbg(&adapter
->dev
, "Creating %s at 0x%02x\n",
1825 info
.type
, info
.addr
);
1826 client
= i2c_new_device(adapter
, &info
);
1828 list_add_tail(&client
->detected
, &driver
->clients
);
1830 dev_err(&adapter
->dev
, "Failed creating %s at 0x%02x\n",
1831 info
.type
, info
.addr
);
1836 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
)
1838 const unsigned short *address_list
;
1839 struct i2c_client
*temp_client
;
1841 int adap_id
= i2c_adapter_id(adapter
);
1843 address_list
= driver
->address_list
;
1844 if (!driver
->detect
|| !address_list
)
1847 /* Stop here if the classes do not match */
1848 if (!(adapter
->class & driver
->class))
1851 /* Set up a temporary client to help detect callback */
1852 temp_client
= kzalloc(sizeof(struct i2c_client
), GFP_KERNEL
);
1855 temp_client
->adapter
= adapter
;
1857 for (i
= 0; address_list
[i
] != I2C_CLIENT_END
; i
+= 1) {
1858 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
1859 "addr 0x%02x\n", adap_id
, address_list
[i
]);
1860 temp_client
->addr
= address_list
[i
];
1861 err
= i2c_detect_address(temp_client
, driver
);
1870 int i2c_probe_func_quick_read(struct i2c_adapter
*adap
, unsigned short addr
)
1872 return i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
1873 I2C_SMBUS_QUICK
, NULL
) >= 0;
1875 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read
);
1878 i2c_new_probed_device(struct i2c_adapter
*adap
,
1879 struct i2c_board_info
*info
,
1880 unsigned short const *addr_list
,
1881 int (*probe
)(struct i2c_adapter
*, unsigned short addr
))
1886 probe
= i2c_default_probe
;
1888 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
1889 /* Check address validity */
1890 if (i2c_check_addr_validity(addr_list
[i
]) < 0) {
1891 dev_warn(&adap
->dev
, "Invalid 7-bit address "
1892 "0x%02x\n", addr_list
[i
]);
1896 /* Check address availability */
1897 if (i2c_check_addr_busy(adap
, addr_list
[i
])) {
1898 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
1899 "use, not probing\n", addr_list
[i
]);
1903 /* Test address responsiveness */
1904 if (probe(adap
, addr_list
[i
]))
1908 if (addr_list
[i
] == I2C_CLIENT_END
) {
1909 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
1913 info
->addr
= addr_list
[i
];
1914 return i2c_new_device(adap
, info
);
1916 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
1918 struct i2c_adapter
*i2c_get_adapter(int nr
)
1920 struct i2c_adapter
*adapter
;
1922 mutex_lock(&core_lock
);
1923 adapter
= idr_find(&i2c_adapter_idr
, nr
);
1924 if (adapter
&& !try_module_get(adapter
->owner
))
1927 mutex_unlock(&core_lock
);
1930 EXPORT_SYMBOL(i2c_get_adapter
);
1932 void i2c_put_adapter(struct i2c_adapter
*adap
)
1935 module_put(adap
->owner
);
1937 EXPORT_SYMBOL(i2c_put_adapter
);
1939 /* The SMBus parts */
1941 #define POLY (0x1070U << 3)
1942 static u8
crc8(u16 data
)
1946 for (i
= 0; i
< 8; i
++) {
1951 return (u8
)(data
>> 8);
1954 /* Incremental CRC8 over count bytes in the array pointed to by p */
1955 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
1959 for (i
= 0; i
< count
; i
++)
1960 crc
= crc8((crc
^ p
[i
]) << 8);
1964 /* Assume a 7-bit address, which is reasonable for SMBus */
1965 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
1967 /* The address will be sent first */
1968 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
1969 pec
= i2c_smbus_pec(pec
, &addr
, 1);
1971 /* The data buffer follows */
1972 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
1975 /* Used for write only transactions */
1976 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
1978 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
1982 /* Return <0 on CRC error
1983 If there was a write before this read (most cases) we need to take the
1984 partial CRC from the write part into account.
1985 Note that this function does modify the message (we need to decrease the
1986 message length to hide the CRC byte from the caller). */
1987 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
1989 u8 rpec
= msg
->buf
[--msg
->len
];
1990 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
1993 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2001 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2002 * @client: Handle to slave device
2004 * This executes the SMBus "receive byte" protocol, returning negative errno
2005 * else the byte received from the device.
2007 s32
i2c_smbus_read_byte(const struct i2c_client
*client
)
2009 union i2c_smbus_data data
;
2012 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2014 I2C_SMBUS_BYTE
, &data
);
2015 return (status
< 0) ? status
: data
.byte
;
2017 EXPORT_SYMBOL(i2c_smbus_read_byte
);
2020 * i2c_smbus_write_byte - SMBus "send byte" protocol
2021 * @client: Handle to slave device
2022 * @value: Byte to be sent
2024 * This executes the SMBus "send byte" protocol, returning negative errno
2025 * else zero on success.
2027 s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
)
2029 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2030 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
2032 EXPORT_SYMBOL(i2c_smbus_write_byte
);
2035 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2036 * @client: Handle to slave device
2037 * @command: Byte interpreted by slave
2039 * This executes the SMBus "read byte" protocol, returning negative errno
2040 * else a data byte received from the device.
2042 s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
, u8 command
)
2044 union i2c_smbus_data data
;
2047 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2048 I2C_SMBUS_READ
, command
,
2049 I2C_SMBUS_BYTE_DATA
, &data
);
2050 return (status
< 0) ? status
: data
.byte
;
2052 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
2055 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2056 * @client: Handle to slave device
2057 * @command: Byte interpreted by slave
2058 * @value: Byte being written
2060 * This executes the SMBus "write byte" protocol, returning negative errno
2061 * else zero on success.
2063 s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
, u8 command
,
2066 union i2c_smbus_data data
;
2068 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2069 I2C_SMBUS_WRITE
, command
,
2070 I2C_SMBUS_BYTE_DATA
, &data
);
2072 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
2075 * i2c_smbus_read_word_data - SMBus "read word" protocol
2076 * @client: Handle to slave device
2077 * @command: Byte interpreted by slave
2079 * This executes the SMBus "read word" protocol, returning negative errno
2080 * else a 16-bit unsigned "word" received from the device.
2082 s32
i2c_smbus_read_word_data(const struct i2c_client
*client
, u8 command
)
2084 union i2c_smbus_data data
;
2087 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2088 I2C_SMBUS_READ
, command
,
2089 I2C_SMBUS_WORD_DATA
, &data
);
2090 return (status
< 0) ? status
: data
.word
;
2092 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
2095 * i2c_smbus_write_word_data - SMBus "write word" protocol
2096 * @client: Handle to slave device
2097 * @command: Byte interpreted by slave
2098 * @value: 16-bit "word" being written
2100 * This executes the SMBus "write word" protocol, returning negative errno
2101 * else zero on success.
2103 s32
i2c_smbus_write_word_data(const struct i2c_client
*client
, u8 command
,
2106 union i2c_smbus_data data
;
2108 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2109 I2C_SMBUS_WRITE
, command
,
2110 I2C_SMBUS_WORD_DATA
, &data
);
2112 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
2115 * i2c_smbus_read_block_data - SMBus "block read" protocol
2116 * @client: Handle to slave device
2117 * @command: Byte interpreted by slave
2118 * @values: Byte array into which data will be read; big enough to hold
2119 * the data returned by the slave. SMBus allows at most 32 bytes.
2121 * This executes the SMBus "block read" protocol, returning negative errno
2122 * else the number of data bytes in the slave's response.
2124 * Note that using this function requires that the client's adapter support
2125 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2126 * support this; its emulation through I2C messaging relies on a specific
2127 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2129 s32
i2c_smbus_read_block_data(const struct i2c_client
*client
, u8 command
,
2132 union i2c_smbus_data data
;
2135 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2136 I2C_SMBUS_READ
, command
,
2137 I2C_SMBUS_BLOCK_DATA
, &data
);
2141 memcpy(values
, &data
.block
[1], data
.block
[0]);
2142 return data
.block
[0];
2144 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
2147 * i2c_smbus_write_block_data - SMBus "block write" protocol
2148 * @client: Handle to slave device
2149 * @command: Byte interpreted by slave
2150 * @length: Size of data block; SMBus allows at most 32 bytes
2151 * @values: Byte array which will be written.
2153 * This executes the SMBus "block write" protocol, returning negative errno
2154 * else zero on success.
2156 s32
i2c_smbus_write_block_data(const struct i2c_client
*client
, u8 command
,
2157 u8 length
, const u8
*values
)
2159 union i2c_smbus_data data
;
2161 if (length
> I2C_SMBUS_BLOCK_MAX
)
2162 length
= I2C_SMBUS_BLOCK_MAX
;
2163 data
.block
[0] = length
;
2164 memcpy(&data
.block
[1], values
, length
);
2165 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2166 I2C_SMBUS_WRITE
, command
,
2167 I2C_SMBUS_BLOCK_DATA
, &data
);
2169 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
2171 /* Returns the number of read bytes */
2172 s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2173 u8 length
, u8
*values
)
2175 union i2c_smbus_data data
;
2178 if (length
> I2C_SMBUS_BLOCK_MAX
)
2179 length
= I2C_SMBUS_BLOCK_MAX
;
2180 data
.block
[0] = length
;
2181 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2182 I2C_SMBUS_READ
, command
,
2183 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2187 memcpy(values
, &data
.block
[1], data
.block
[0]);
2188 return data
.block
[0];
2190 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
2192 s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
, u8 command
,
2193 u8 length
, const u8
*values
)
2195 union i2c_smbus_data data
;
2197 if (length
> I2C_SMBUS_BLOCK_MAX
)
2198 length
= I2C_SMBUS_BLOCK_MAX
;
2199 data
.block
[0] = length
;
2200 memcpy(data
.block
+ 1, values
, length
);
2201 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
2202 I2C_SMBUS_WRITE
, command
,
2203 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
2205 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
2207 /* Simulate a SMBus command using the i2c protocol
2208 No checking of parameters is done! */
2209 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
*adapter
, u16 addr
,
2210 unsigned short flags
,
2211 char read_write
, u8 command
, int size
,
2212 union i2c_smbus_data
*data
)
2214 /* So we need to generate a series of msgs. In the case of writing, we
2215 need to use only one message; when reading, we need two. We initialize
2216 most things with sane defaults, to keep the code below somewhat
2218 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
2219 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
2220 int num
= read_write
== I2C_SMBUS_READ
? 2 : 1;
2224 struct i2c_msg msg
[2] = {
2232 .flags
= flags
| I2C_M_RD
,
2238 msgbuf0
[0] = command
;
2240 case I2C_SMBUS_QUICK
:
2242 /* Special case: The read/write field is used as data */
2243 msg
[0].flags
= flags
| (read_write
== I2C_SMBUS_READ
?
2247 case I2C_SMBUS_BYTE
:
2248 if (read_write
== I2C_SMBUS_READ
) {
2249 /* Special case: only a read! */
2250 msg
[0].flags
= I2C_M_RD
| flags
;
2254 case I2C_SMBUS_BYTE_DATA
:
2255 if (read_write
== I2C_SMBUS_READ
)
2259 msgbuf0
[1] = data
->byte
;
2262 case I2C_SMBUS_WORD_DATA
:
2263 if (read_write
== I2C_SMBUS_READ
)
2267 msgbuf0
[1] = data
->word
& 0xff;
2268 msgbuf0
[2] = data
->word
>> 8;
2271 case I2C_SMBUS_PROC_CALL
:
2272 num
= 2; /* Special case */
2273 read_write
= I2C_SMBUS_READ
;
2276 msgbuf0
[1] = data
->word
& 0xff;
2277 msgbuf0
[2] = data
->word
>> 8;
2279 case I2C_SMBUS_BLOCK_DATA
:
2280 if (read_write
== I2C_SMBUS_READ
) {
2281 msg
[1].flags
|= I2C_M_RECV_LEN
;
2282 msg
[1].len
= 1; /* block length will be added by
2283 the underlying bus driver */
2285 msg
[0].len
= data
->block
[0] + 2;
2286 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
2287 dev_err(&adapter
->dev
,
2288 "Invalid block write size %d\n",
2292 for (i
= 1; i
< msg
[0].len
; i
++)
2293 msgbuf0
[i
] = data
->block
[i
-1];
2296 case I2C_SMBUS_BLOCK_PROC_CALL
:
2297 num
= 2; /* Another special case */
2298 read_write
= I2C_SMBUS_READ
;
2299 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
2300 dev_err(&adapter
->dev
,
2301 "Invalid block write size %d\n",
2305 msg
[0].len
= data
->block
[0] + 2;
2306 for (i
= 1; i
< msg
[0].len
; i
++)
2307 msgbuf0
[i
] = data
->block
[i
-1];
2308 msg
[1].flags
|= I2C_M_RECV_LEN
;
2309 msg
[1].len
= 1; /* block length will be added by
2310 the underlying bus driver */
2312 case I2C_SMBUS_I2C_BLOCK_DATA
:
2313 if (read_write
== I2C_SMBUS_READ
) {
2314 msg
[1].len
= data
->block
[0];
2316 msg
[0].len
= data
->block
[0] + 1;
2317 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
2318 dev_err(&adapter
->dev
,
2319 "Invalid block write size %d\n",
2323 for (i
= 1; i
<= data
->block
[0]; i
++)
2324 msgbuf0
[i
] = data
->block
[i
];
2328 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
2332 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
2333 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
2335 /* Compute PEC if first message is a write */
2336 if (!(msg
[0].flags
& I2C_M_RD
)) {
2337 if (num
== 1) /* Write only */
2338 i2c_smbus_add_pec(&msg
[0]);
2339 else /* Write followed by read */
2340 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
2342 /* Ask for PEC if last message is a read */
2343 if (msg
[num
-1].flags
& I2C_M_RD
)
2347 status
= i2c_transfer(adapter
, msg
, num
);
2351 /* Check PEC if last message is a read */
2352 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
2353 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
2358 if (read_write
== I2C_SMBUS_READ
)
2360 case I2C_SMBUS_BYTE
:
2361 data
->byte
= msgbuf0
[0];
2363 case I2C_SMBUS_BYTE_DATA
:
2364 data
->byte
= msgbuf1
[0];
2366 case I2C_SMBUS_WORD_DATA
:
2367 case I2C_SMBUS_PROC_CALL
:
2368 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
2370 case I2C_SMBUS_I2C_BLOCK_DATA
:
2371 for (i
= 0; i
< data
->block
[0]; i
++)
2372 data
->block
[i
+1] = msgbuf1
[i
];
2374 case I2C_SMBUS_BLOCK_DATA
:
2375 case I2C_SMBUS_BLOCK_PROC_CALL
:
2376 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
2377 data
->block
[i
] = msgbuf1
[i
];
2384 * i2c_smbus_xfer - execute SMBus protocol operations
2385 * @adapter: Handle to I2C bus
2386 * @addr: Address of SMBus slave on that bus
2387 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2388 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2389 * @command: Byte interpreted by slave, for protocols which use such bytes
2390 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2391 * @data: Data to be read or written
2393 * This executes an SMBus protocol operation, and returns a negative
2394 * errno code else zero on success.
2396 s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
, unsigned short flags
,
2397 char read_write
, u8 command
, int protocol
,
2398 union i2c_smbus_data
*data
)
2400 unsigned long orig_jiffies
;
2404 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
| I2C_CLIENT_SCCB
;
2406 if (adapter
->algo
->smbus_xfer
) {
2407 i2c_lock_adapter(adapter
);
2409 /* Retry automatically on arbitration loss */
2410 orig_jiffies
= jiffies
;
2411 for (res
= 0, try = 0; try <= adapter
->retries
; try++) {
2412 res
= adapter
->algo
->smbus_xfer(adapter
, addr
, flags
,
2413 read_write
, command
,
2417 if (time_after(jiffies
,
2418 orig_jiffies
+ adapter
->timeout
))
2421 i2c_unlock_adapter(adapter
);
2423 if (res
!= -EOPNOTSUPP
|| !adapter
->algo
->master_xfer
)
2426 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2427 * implement native support for the SMBus operation.
2431 return i2c_smbus_xfer_emulated(adapter
, addr
, flags
, read_write
,
2432 command
, protocol
, data
);
2434 EXPORT_SYMBOL(i2c_smbus_xfer
);
2436 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2437 MODULE_DESCRIPTION("I2C-Bus main module");
2438 MODULE_LICENSE("GPL");