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., 675 Mass Ave, Cambridge, MA 02139, USA. */
18 /* ------------------------------------------------------------------------- */
20 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
21 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
22 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
23 Jean Delvare <khali@linux-fr.org>
24 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
25 Michael Lawnick <michael.lawnick.ext@nsn.com> */
27 #include <linux/module.h>
28 #include <linux/kernel.h>
29 #include <linux/errno.h>
30 #include <linux/slab.h>
31 #include <linux/i2c.h>
32 #include <linux/init.h>
33 #include <linux/idr.h>
34 #include <linux/mutex.h>
35 #include <linux/of_device.h>
36 #include <linux/completion.h>
37 #include <linux/hardirq.h>
38 #include <linux/irqflags.h>
39 #include <linux/rwsem.h>
40 #include <linux/pm_runtime.h>
41 #include <asm/uaccess.h>
46 /* core_lock protects i2c_adapter_idr, and guarantees
47 that device detection, deletion of detected devices, and attach_adapter
48 and detach_adapter calls are serialized */
49 static DEFINE_MUTEX(core_lock
);
50 static DEFINE_IDR(i2c_adapter_idr
);
52 static struct device_type i2c_client_type
;
53 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
);
55 /* ------------------------------------------------------------------------- */
57 static const struct i2c_device_id
*i2c_match_id(const struct i2c_device_id
*id
,
58 const struct i2c_client
*client
)
61 if (strcmp(client
->name
, id
->name
) == 0)
68 static int i2c_device_match(struct device
*dev
, struct device_driver
*drv
)
70 struct i2c_client
*client
= i2c_verify_client(dev
);
71 struct i2c_driver
*driver
;
76 /* Attempt an OF style match */
77 if (of_driver_match_device(dev
, drv
))
80 driver
= to_i2c_driver(drv
);
81 /* match on an id table if there is one */
83 return i2c_match_id(driver
->id_table
, client
) != NULL
;
90 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
91 static int i2c_device_uevent(struct device
*dev
, struct kobj_uevent_env
*env
)
93 struct i2c_client
*client
= to_i2c_client(dev
);
95 if (add_uevent_var(env
, "MODALIAS=%s%s",
96 I2C_MODULE_PREFIX
, client
->name
))
98 dev_dbg(dev
, "uevent\n");
103 #define i2c_device_uevent NULL
104 #endif /* CONFIG_HOTPLUG */
106 static int i2c_device_probe(struct device
*dev
)
108 struct i2c_client
*client
= i2c_verify_client(dev
);
109 struct i2c_driver
*driver
;
115 driver
= to_i2c_driver(dev
->driver
);
116 if (!driver
->probe
|| !driver
->id_table
)
118 client
->driver
= driver
;
119 if (!device_can_wakeup(&client
->dev
))
120 device_init_wakeup(&client
->dev
,
121 client
->flags
& I2C_CLIENT_WAKE
);
122 dev_dbg(dev
, "probe\n");
124 status
= driver
->probe(client
, i2c_match_id(driver
->id_table
, client
));
126 client
->driver
= NULL
;
127 i2c_set_clientdata(client
, NULL
);
132 static int i2c_device_remove(struct device
*dev
)
134 struct i2c_client
*client
= i2c_verify_client(dev
);
135 struct i2c_driver
*driver
;
138 if (!client
|| !dev
->driver
)
141 driver
= to_i2c_driver(dev
->driver
);
142 if (driver
->remove
) {
143 dev_dbg(dev
, "remove\n");
144 status
= driver
->remove(client
);
150 client
->driver
= NULL
;
151 i2c_set_clientdata(client
, NULL
);
156 static void i2c_device_shutdown(struct device
*dev
)
158 struct i2c_client
*client
= i2c_verify_client(dev
);
159 struct i2c_driver
*driver
;
161 if (!client
|| !dev
->driver
)
163 driver
= to_i2c_driver(dev
->driver
);
164 if (driver
->shutdown
)
165 driver
->shutdown(client
);
168 #ifdef CONFIG_PM_SLEEP
169 static int i2c_legacy_suspend(struct device
*dev
, pm_message_t mesg
)
171 struct i2c_client
*client
= i2c_verify_client(dev
);
172 struct i2c_driver
*driver
;
174 if (!client
|| !dev
->driver
)
176 driver
= to_i2c_driver(dev
->driver
);
177 if (!driver
->suspend
)
179 return driver
->suspend(client
, mesg
);
182 static int i2c_legacy_resume(struct device
*dev
)
184 struct i2c_client
*client
= i2c_verify_client(dev
);
185 struct i2c_driver
*driver
;
187 if (!client
|| !dev
->driver
)
189 driver
= to_i2c_driver(dev
->driver
);
192 return driver
->resume(client
);
195 static int i2c_device_pm_suspend(struct device
*dev
)
197 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
200 return pm_generic_suspend(dev
);
202 return i2c_legacy_suspend(dev
, PMSG_SUSPEND
);
205 static int i2c_device_pm_resume(struct device
*dev
)
207 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
210 return pm_generic_resume(dev
);
212 return i2c_legacy_resume(dev
);
215 static int i2c_device_pm_freeze(struct device
*dev
)
217 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
220 return pm_generic_freeze(dev
);
222 return i2c_legacy_suspend(dev
, PMSG_FREEZE
);
225 static int i2c_device_pm_thaw(struct device
*dev
)
227 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
230 return pm_generic_thaw(dev
);
232 return i2c_legacy_resume(dev
);
235 static int i2c_device_pm_poweroff(struct device
*dev
)
237 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
240 return pm_generic_poweroff(dev
);
242 return i2c_legacy_suspend(dev
, PMSG_HIBERNATE
);
245 static int i2c_device_pm_restore(struct device
*dev
)
247 const struct dev_pm_ops
*pm
= dev
->driver
? dev
->driver
->pm
: NULL
;
250 return pm_generic_restore(dev
);
252 return i2c_legacy_resume(dev
);
254 #else /* !CONFIG_PM_SLEEP */
255 #define i2c_device_pm_suspend NULL
256 #define i2c_device_pm_resume NULL
257 #define i2c_device_pm_freeze NULL
258 #define i2c_device_pm_thaw NULL
259 #define i2c_device_pm_poweroff NULL
260 #define i2c_device_pm_restore NULL
261 #endif /* !CONFIG_PM_SLEEP */
263 static void i2c_client_dev_release(struct device
*dev
)
265 kfree(to_i2c_client(dev
));
269 show_name(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
271 return sprintf(buf
, "%s\n", dev
->type
== &i2c_client_type
?
272 to_i2c_client(dev
)->name
: to_i2c_adapter(dev
)->name
);
276 show_modalias(struct device
*dev
, struct device_attribute
*attr
, char *buf
)
278 struct i2c_client
*client
= to_i2c_client(dev
);
279 return sprintf(buf
, "%s%s\n", I2C_MODULE_PREFIX
, client
->name
);
282 static DEVICE_ATTR(name
, S_IRUGO
, show_name
, NULL
);
283 static DEVICE_ATTR(modalias
, S_IRUGO
, show_modalias
, NULL
);
285 static struct attribute
*i2c_dev_attrs
[] = {
287 /* modalias helps coldplug: modprobe $(cat .../modalias) */
288 &dev_attr_modalias
.attr
,
292 static struct attribute_group i2c_dev_attr_group
= {
293 .attrs
= i2c_dev_attrs
,
296 static const struct attribute_group
*i2c_dev_attr_groups
[] = {
301 static const struct dev_pm_ops i2c_device_pm_ops
= {
302 .suspend
= i2c_device_pm_suspend
,
303 .resume
= i2c_device_pm_resume
,
304 .freeze
= i2c_device_pm_freeze
,
305 .thaw
= i2c_device_pm_thaw
,
306 .poweroff
= i2c_device_pm_poweroff
,
307 .restore
= i2c_device_pm_restore
,
309 pm_generic_runtime_suspend
,
310 pm_generic_runtime_resume
,
311 pm_generic_runtime_idle
315 struct bus_type i2c_bus_type
= {
317 .match
= i2c_device_match
,
318 .probe
= i2c_device_probe
,
319 .remove
= i2c_device_remove
,
320 .shutdown
= i2c_device_shutdown
,
321 .pm
= &i2c_device_pm_ops
,
323 EXPORT_SYMBOL_GPL(i2c_bus_type
);
325 static struct device_type i2c_client_type
= {
326 .groups
= i2c_dev_attr_groups
,
327 .uevent
= i2c_device_uevent
,
328 .release
= i2c_client_dev_release
,
333 * i2c_verify_client - return parameter as i2c_client, or NULL
334 * @dev: device, probably from some driver model iterator
336 * When traversing the driver model tree, perhaps using driver model
337 * iterators like @device_for_each_child(), you can't assume very much
338 * about the nodes you find. Use this function to avoid oopses caused
339 * by wrongly treating some non-I2C device as an i2c_client.
341 struct i2c_client
*i2c_verify_client(struct device
*dev
)
343 return (dev
->type
== &i2c_client_type
)
347 EXPORT_SYMBOL(i2c_verify_client
);
350 /* This is a permissive address validity check, I2C address map constraints
351 * are purposedly not enforced, except for the general call address. */
352 static int i2c_check_client_addr_validity(const struct i2c_client
*client
)
354 if (client
->flags
& I2C_CLIENT_TEN
) {
355 /* 10-bit address, all values are valid */
356 if (client
->addr
> 0x3ff)
359 /* 7-bit address, reject the general call address */
360 if (client
->addr
== 0x00 || client
->addr
> 0x7f)
366 /* And this is a strict address validity check, used when probing. If a
367 * device uses a reserved address, then it shouldn't be probed. 7-bit
368 * addressing is assumed, 10-bit address devices are rare and should be
369 * explicitly enumerated. */
370 static int i2c_check_addr_validity(unsigned short addr
)
373 * Reserved addresses per I2C specification:
374 * 0x00 General call address / START byte
376 * 0x02 Reserved for different bus format
377 * 0x03 Reserved for future purposes
378 * 0x04-0x07 Hs-mode master code
379 * 0x78-0x7b 10-bit slave addressing
380 * 0x7c-0x7f Reserved for future purposes
382 if (addr
< 0x08 || addr
> 0x77)
387 static int __i2c_check_addr_busy(struct device
*dev
, void *addrp
)
389 struct i2c_client
*client
= i2c_verify_client(dev
);
390 int addr
= *(int *)addrp
;
392 if (client
&& client
->addr
== addr
)
397 /* walk up mux tree */
398 static int i2c_check_mux_parents(struct i2c_adapter
*adapter
, int addr
)
400 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
403 result
= device_for_each_child(&adapter
->dev
, &addr
,
404 __i2c_check_addr_busy
);
406 if (!result
&& parent
)
407 result
= i2c_check_mux_parents(parent
, addr
);
412 /* recurse down mux tree */
413 static int i2c_check_mux_children(struct device
*dev
, void *addrp
)
417 if (dev
->type
== &i2c_adapter_type
)
418 result
= device_for_each_child(dev
, addrp
,
419 i2c_check_mux_children
);
421 result
= __i2c_check_addr_busy(dev
, addrp
);
426 static int i2c_check_addr_busy(struct i2c_adapter
*adapter
, int addr
)
428 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
432 result
= i2c_check_mux_parents(parent
, addr
);
435 result
= device_for_each_child(&adapter
->dev
, &addr
,
436 i2c_check_mux_children
);
442 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
443 * @adapter: Target I2C bus segment
445 void i2c_lock_adapter(struct i2c_adapter
*adapter
)
447 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
450 i2c_lock_adapter(parent
);
452 rt_mutex_lock(&adapter
->bus_lock
);
454 EXPORT_SYMBOL_GPL(i2c_lock_adapter
);
457 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
458 * @adapter: Target I2C bus segment
460 static int i2c_trylock_adapter(struct i2c_adapter
*adapter
)
462 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
465 return i2c_trylock_adapter(parent
);
467 return rt_mutex_trylock(&adapter
->bus_lock
);
471 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
472 * @adapter: Target I2C bus segment
474 void i2c_unlock_adapter(struct i2c_adapter
*adapter
)
476 struct i2c_adapter
*parent
= i2c_parent_is_i2c_adapter(adapter
);
479 i2c_unlock_adapter(parent
);
481 rt_mutex_unlock(&adapter
->bus_lock
);
483 EXPORT_SYMBOL_GPL(i2c_unlock_adapter
);
486 * i2c_new_device - instantiate an i2c device
487 * @adap: the adapter managing the device
488 * @info: describes one I2C device; bus_num is ignored
491 * Create an i2c device. Binding is handled through driver model
492 * probe()/remove() methods. A driver may be bound to this device when we
493 * return from this function, or any later moment (e.g. maybe hotplugging will
494 * load the driver module). This call is not appropriate for use by mainboard
495 * initialization logic, which usually runs during an arch_initcall() long
496 * before any i2c_adapter could exist.
498 * This returns the new i2c client, which may be saved for later use with
499 * i2c_unregister_device(); or NULL to indicate an error.
502 i2c_new_device(struct i2c_adapter
*adap
, struct i2c_board_info
const *info
)
504 struct i2c_client
*client
;
507 client
= kzalloc(sizeof *client
, GFP_KERNEL
);
511 client
->adapter
= adap
;
513 client
->dev
.platform_data
= info
->platform_data
;
516 client
->dev
.archdata
= *info
->archdata
;
518 client
->flags
= info
->flags
;
519 client
->addr
= info
->addr
;
520 client
->irq
= info
->irq
;
522 strlcpy(client
->name
, info
->type
, sizeof(client
->name
));
524 /* Check for address validity */
525 status
= i2c_check_client_addr_validity(client
);
527 dev_err(&adap
->dev
, "Invalid %d-bit I2C address 0x%02hx\n",
528 client
->flags
& I2C_CLIENT_TEN
? 10 : 7, client
->addr
);
532 /* Check for address business */
533 status
= i2c_check_addr_busy(adap
, client
->addr
);
537 client
->dev
.parent
= &client
->adapter
->dev
;
538 client
->dev
.bus
= &i2c_bus_type
;
539 client
->dev
.type
= &i2c_client_type
;
540 client
->dev
.of_node
= info
->of_node
;
542 dev_set_name(&client
->dev
, "%d-%04x", i2c_adapter_id(adap
),
544 status
= device_register(&client
->dev
);
548 dev_dbg(&adap
->dev
, "client [%s] registered with bus id %s\n",
549 client
->name
, dev_name(&client
->dev
));
554 dev_err(&adap
->dev
, "Failed to register i2c client %s at 0x%02x "
555 "(%d)\n", client
->name
, client
->addr
, status
);
560 EXPORT_SYMBOL_GPL(i2c_new_device
);
564 * i2c_unregister_device - reverse effect of i2c_new_device()
565 * @client: value returned from i2c_new_device()
568 void i2c_unregister_device(struct i2c_client
*client
)
570 device_unregister(&client
->dev
);
572 EXPORT_SYMBOL_GPL(i2c_unregister_device
);
575 static const struct i2c_device_id dummy_id
[] = {
580 static int dummy_probe(struct i2c_client
*client
,
581 const struct i2c_device_id
*id
)
586 static int dummy_remove(struct i2c_client
*client
)
591 static struct i2c_driver dummy_driver
= {
592 .driver
.name
= "dummy",
593 .probe
= dummy_probe
,
594 .remove
= dummy_remove
,
595 .id_table
= dummy_id
,
599 * i2c_new_dummy - return a new i2c device bound to a dummy driver
600 * @adapter: the adapter managing the device
601 * @address: seven bit address to be used
604 * This returns an I2C client bound to the "dummy" driver, intended for use
605 * with devices that consume multiple addresses. Examples of such chips
606 * include various EEPROMS (like 24c04 and 24c08 models).
608 * These dummy devices have two main uses. First, most I2C and SMBus calls
609 * except i2c_transfer() need a client handle; the dummy will be that handle.
610 * And second, this prevents the specified address from being bound to a
613 * This returns the new i2c client, which should be saved for later use with
614 * i2c_unregister_device(); or NULL to indicate an error.
616 struct i2c_client
*i2c_new_dummy(struct i2c_adapter
*adapter
, u16 address
)
618 struct i2c_board_info info
= {
619 I2C_BOARD_INFO("dummy", address
),
622 return i2c_new_device(adapter
, &info
);
624 EXPORT_SYMBOL_GPL(i2c_new_dummy
);
626 /* ------------------------------------------------------------------------- */
628 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
630 static void i2c_adapter_dev_release(struct device
*dev
)
632 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
633 complete(&adap
->dev_released
);
637 * Let users instantiate I2C devices through sysfs. This can be used when
638 * platform initialization code doesn't contain the proper data for
639 * whatever reason. Also useful for drivers that do device detection and
640 * detection fails, either because the device uses an unexpected address,
641 * or this is a compatible device with different ID register values.
643 * Parameter checking may look overzealous, but we really don't want
644 * the user to provide incorrect parameters.
647 i2c_sysfs_new_device(struct device
*dev
, struct device_attribute
*attr
,
648 const char *buf
, size_t count
)
650 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
651 struct i2c_board_info info
;
652 struct i2c_client
*client
;
656 memset(&info
, 0, sizeof(struct i2c_board_info
));
658 blank
= strchr(buf
, ' ');
660 dev_err(dev
, "%s: Missing parameters\n", "new_device");
663 if (blank
- buf
> I2C_NAME_SIZE
- 1) {
664 dev_err(dev
, "%s: Invalid device name\n", "new_device");
667 memcpy(info
.type
, buf
, blank
- buf
);
669 /* Parse remaining parameters, reject extra parameters */
670 res
= sscanf(++blank
, "%hi%c", &info
.addr
, &end
);
672 dev_err(dev
, "%s: Can't parse I2C address\n", "new_device");
675 if (res
> 1 && end
!= '\n') {
676 dev_err(dev
, "%s: Extra parameters\n", "new_device");
680 client
= i2c_new_device(adap
, &info
);
684 /* Keep track of the added device */
685 mutex_lock(&adap
->userspace_clients_lock
);
686 list_add_tail(&client
->detected
, &adap
->userspace_clients
);
687 mutex_unlock(&adap
->userspace_clients_lock
);
688 dev_info(dev
, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
689 info
.type
, info
.addr
);
695 * And of course let the users delete the devices they instantiated, if
696 * they got it wrong. This interface can only be used to delete devices
697 * instantiated by i2c_sysfs_new_device above. This guarantees that we
698 * don't delete devices to which some kernel code still has references.
700 * Parameter checking may look overzealous, but we really don't want
701 * the user to delete the wrong device.
704 i2c_sysfs_delete_device(struct device
*dev
, struct device_attribute
*attr
,
705 const char *buf
, size_t count
)
707 struct i2c_adapter
*adap
= to_i2c_adapter(dev
);
708 struct i2c_client
*client
, *next
;
713 /* Parse parameters, reject extra parameters */
714 res
= sscanf(buf
, "%hi%c", &addr
, &end
);
716 dev_err(dev
, "%s: Can't parse I2C address\n", "delete_device");
719 if (res
> 1 && end
!= '\n') {
720 dev_err(dev
, "%s: Extra parameters\n", "delete_device");
724 /* Make sure the device was added through sysfs */
726 mutex_lock(&adap
->userspace_clients_lock
);
727 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
729 if (client
->addr
== addr
) {
730 dev_info(dev
, "%s: Deleting device %s at 0x%02hx\n",
731 "delete_device", client
->name
, client
->addr
);
733 list_del(&client
->detected
);
734 i2c_unregister_device(client
);
739 mutex_unlock(&adap
->userspace_clients_lock
);
742 dev_err(dev
, "%s: Can't find device in list\n",
747 static DEVICE_ATTR(new_device
, S_IWUSR
, NULL
, i2c_sysfs_new_device
);
748 static DEVICE_ATTR(delete_device
, S_IWUSR
, NULL
, i2c_sysfs_delete_device
);
750 static struct attribute
*i2c_adapter_attrs
[] = {
752 &dev_attr_new_device
.attr
,
753 &dev_attr_delete_device
.attr
,
757 static struct attribute_group i2c_adapter_attr_group
= {
758 .attrs
= i2c_adapter_attrs
,
761 static const struct attribute_group
*i2c_adapter_attr_groups
[] = {
762 &i2c_adapter_attr_group
,
766 struct device_type i2c_adapter_type
= {
767 .groups
= i2c_adapter_attr_groups
,
768 .release
= i2c_adapter_dev_release
,
770 EXPORT_SYMBOL_GPL(i2c_adapter_type
);
772 #ifdef CONFIG_I2C_COMPAT
773 static struct class_compat
*i2c_adapter_compat_class
;
776 static void i2c_scan_static_board_info(struct i2c_adapter
*adapter
)
778 struct i2c_devinfo
*devinfo
;
780 down_read(&__i2c_board_lock
);
781 list_for_each_entry(devinfo
, &__i2c_board_list
, list
) {
782 if (devinfo
->busnum
== adapter
->nr
783 && !i2c_new_device(adapter
,
784 &devinfo
->board_info
))
785 dev_err(&adapter
->dev
,
786 "Can't create device at 0x%02x\n",
787 devinfo
->board_info
.addr
);
789 up_read(&__i2c_board_lock
);
792 static int i2c_do_add_adapter(struct i2c_driver
*driver
,
793 struct i2c_adapter
*adap
)
795 /* Detect supported devices on that bus, and instantiate them */
796 i2c_detect(adap
, driver
);
798 /* Let legacy drivers scan this bus for matching devices */
799 if (driver
->attach_adapter
) {
800 /* We ignore the return code; if it fails, too bad */
801 driver
->attach_adapter(adap
);
806 static int __process_new_adapter(struct device_driver
*d
, void *data
)
808 return i2c_do_add_adapter(to_i2c_driver(d
), data
);
811 static int i2c_register_adapter(struct i2c_adapter
*adap
)
815 /* Can't register until after driver model init */
816 if (unlikely(WARN_ON(!i2c_bus_type
.p
))) {
822 if (unlikely(adap
->name
[0] == '\0')) {
823 pr_err("i2c-core: Attempt to register an adapter with "
827 if (unlikely(!adap
->algo
)) {
828 pr_err("i2c-core: Attempt to register adapter '%s' with "
829 "no algo!\n", adap
->name
);
833 rt_mutex_init(&adap
->bus_lock
);
834 mutex_init(&adap
->userspace_clients_lock
);
835 INIT_LIST_HEAD(&adap
->userspace_clients
);
837 /* Set default timeout to 1 second if not already set */
838 if (adap
->timeout
== 0)
841 dev_set_name(&adap
->dev
, "i2c-%d", adap
->nr
);
842 adap
->dev
.bus
= &i2c_bus_type
;
843 adap
->dev
.type
= &i2c_adapter_type
;
844 res
= device_register(&adap
->dev
);
848 dev_dbg(&adap
->dev
, "adapter [%s] registered\n", adap
->name
);
850 #ifdef CONFIG_I2C_COMPAT
851 res
= class_compat_create_link(i2c_adapter_compat_class
, &adap
->dev
,
855 "Failed to create compatibility class link\n");
858 /* create pre-declared device nodes */
859 if (adap
->nr
< __i2c_first_dynamic_bus_num
)
860 i2c_scan_static_board_info(adap
);
863 mutex_lock(&core_lock
);
864 bus_for_each_drv(&i2c_bus_type
, NULL
, adap
, __process_new_adapter
);
865 mutex_unlock(&core_lock
);
870 mutex_lock(&core_lock
);
871 idr_remove(&i2c_adapter_idr
, adap
->nr
);
872 mutex_unlock(&core_lock
);
877 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
878 * @adapter: the adapter to add
881 * This routine is used to declare an I2C adapter when its bus number
882 * doesn't matter. Examples: for I2C adapters dynamically added by
883 * USB links or PCI plugin cards.
885 * When this returns zero, a new bus number was allocated and stored
886 * in adap->nr, and the specified adapter became available for clients.
887 * Otherwise, a negative errno value is returned.
889 int i2c_add_adapter(struct i2c_adapter
*adapter
)
894 if (idr_pre_get(&i2c_adapter_idr
, GFP_KERNEL
) == 0)
897 mutex_lock(&core_lock
);
898 /* "above" here means "above or equal to", sigh */
899 res
= idr_get_new_above(&i2c_adapter_idr
, adapter
,
900 __i2c_first_dynamic_bus_num
, &id
);
901 mutex_unlock(&core_lock
);
910 return i2c_register_adapter(adapter
);
912 EXPORT_SYMBOL(i2c_add_adapter
);
915 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
916 * @adap: the adapter to register (with adap->nr initialized)
919 * This routine is used to declare an I2C adapter when its bus number
920 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
921 * or otherwise built in to the system's mainboard, and where i2c_board_info
922 * is used to properly configure I2C devices.
924 * If no devices have pre-been declared for this bus, then be sure to
925 * register the adapter before any dynamically allocated ones. Otherwise
926 * the required bus ID may not be available.
928 * When this returns zero, the specified adapter became available for
929 * clients using the bus number provided in adap->nr. Also, the table
930 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
931 * and the appropriate driver model device nodes are created. Otherwise, a
932 * negative errno value is returned.
934 int i2c_add_numbered_adapter(struct i2c_adapter
*adap
)
939 if (adap
->nr
& ~MAX_ID_MASK
)
943 if (idr_pre_get(&i2c_adapter_idr
, GFP_KERNEL
) == 0)
946 mutex_lock(&core_lock
);
947 /* "above" here means "above or equal to", sigh;
948 * we need the "equal to" result to force the result
950 status
= idr_get_new_above(&i2c_adapter_idr
, adap
, adap
->nr
, &id
);
951 if (status
== 0 && id
!= adap
->nr
) {
953 idr_remove(&i2c_adapter_idr
, id
);
955 mutex_unlock(&core_lock
);
956 if (status
== -EAGAIN
)
960 status
= i2c_register_adapter(adap
);
963 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter
);
965 static int i2c_do_del_adapter(struct i2c_driver
*driver
,
966 struct i2c_adapter
*adapter
)
968 struct i2c_client
*client
, *_n
;
971 /* Remove the devices we created ourselves as the result of hardware
972 * probing (using a driver's detect method) */
973 list_for_each_entry_safe(client
, _n
, &driver
->clients
, detected
) {
974 if (client
->adapter
== adapter
) {
975 dev_dbg(&adapter
->dev
, "Removing %s at 0x%x\n",
976 client
->name
, client
->addr
);
977 list_del(&client
->detected
);
978 i2c_unregister_device(client
);
982 if (!driver
->detach_adapter
)
984 res
= driver
->detach_adapter(adapter
);
986 dev_err(&adapter
->dev
, "detach_adapter failed (%d) "
987 "for driver [%s]\n", res
, driver
->driver
.name
);
991 static int __unregister_client(struct device
*dev
, void *dummy
)
993 struct i2c_client
*client
= i2c_verify_client(dev
);
994 if (client
&& strcmp(client
->name
, "dummy"))
995 i2c_unregister_device(client
);
999 static int __unregister_dummy(struct device
*dev
, void *dummy
)
1001 struct i2c_client
*client
= i2c_verify_client(dev
);
1003 i2c_unregister_device(client
);
1007 static int __process_removed_adapter(struct device_driver
*d
, void *data
)
1009 return i2c_do_del_adapter(to_i2c_driver(d
), data
);
1013 * i2c_del_adapter - unregister I2C adapter
1014 * @adap: the adapter being unregistered
1015 * Context: can sleep
1017 * This unregisters an I2C adapter which was previously registered
1018 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1020 int i2c_del_adapter(struct i2c_adapter
*adap
)
1023 struct i2c_adapter
*found
;
1024 struct i2c_client
*client
, *next
;
1026 /* First make sure that this adapter was ever added */
1027 mutex_lock(&core_lock
);
1028 found
= idr_find(&i2c_adapter_idr
, adap
->nr
);
1029 mutex_unlock(&core_lock
);
1030 if (found
!= adap
) {
1031 pr_debug("i2c-core: attempting to delete unregistered "
1032 "adapter [%s]\n", adap
->name
);
1036 /* Tell drivers about this removal */
1037 mutex_lock(&core_lock
);
1038 res
= bus_for_each_drv(&i2c_bus_type
, NULL
, adap
,
1039 __process_removed_adapter
);
1040 mutex_unlock(&core_lock
);
1044 /* Remove devices instantiated from sysfs */
1045 mutex_lock(&adap
->userspace_clients_lock
);
1046 list_for_each_entry_safe(client
, next
, &adap
->userspace_clients
,
1048 dev_dbg(&adap
->dev
, "Removing %s at 0x%x\n", client
->name
,
1050 list_del(&client
->detected
);
1051 i2c_unregister_device(client
);
1053 mutex_unlock(&adap
->userspace_clients_lock
);
1055 /* Detach any active clients. This can't fail, thus we do not
1056 * check the returned value. This is a two-pass process, because
1057 * we can't remove the dummy devices during the first pass: they
1058 * could have been instantiated by real devices wishing to clean
1059 * them up properly, so we give them a chance to do that first. */
1060 res
= device_for_each_child(&adap
->dev
, NULL
, __unregister_client
);
1061 res
= device_for_each_child(&adap
->dev
, NULL
, __unregister_dummy
);
1063 #ifdef CONFIG_I2C_COMPAT
1064 class_compat_remove_link(i2c_adapter_compat_class
, &adap
->dev
,
1068 /* device name is gone after device_unregister */
1069 dev_dbg(&adap
->dev
, "adapter [%s] unregistered\n", adap
->name
);
1071 /* clean up the sysfs representation */
1072 init_completion(&adap
->dev_released
);
1073 device_unregister(&adap
->dev
);
1075 /* wait for sysfs to drop all references */
1076 wait_for_completion(&adap
->dev_released
);
1079 mutex_lock(&core_lock
);
1080 idr_remove(&i2c_adapter_idr
, adap
->nr
);
1081 mutex_unlock(&core_lock
);
1083 /* Clear the device structure in case this adapter is ever going to be
1085 memset(&adap
->dev
, 0, sizeof(adap
->dev
));
1089 EXPORT_SYMBOL(i2c_del_adapter
);
1092 /* ------------------------------------------------------------------------- */
1094 static int __process_new_driver(struct device
*dev
, void *data
)
1096 if (dev
->type
!= &i2c_adapter_type
)
1098 return i2c_do_add_adapter(data
, to_i2c_adapter(dev
));
1102 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1103 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1106 int i2c_register_driver(struct module
*owner
, struct i2c_driver
*driver
)
1110 /* Can't register until after driver model init */
1111 if (unlikely(WARN_ON(!i2c_bus_type
.p
)))
1114 /* add the driver to the list of i2c drivers in the driver core */
1115 driver
->driver
.owner
= owner
;
1116 driver
->driver
.bus
= &i2c_bus_type
;
1118 /* When registration returns, the driver core
1119 * will have called probe() for all matching-but-unbound devices.
1121 res
= driver_register(&driver
->driver
);
1125 /* Drivers should switch to dev_pm_ops instead. */
1126 if (driver
->suspend
)
1127 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1128 driver
->driver
.name
);
1130 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1131 driver
->driver
.name
);
1133 pr_debug("i2c-core: driver [%s] registered\n", driver
->driver
.name
);
1135 INIT_LIST_HEAD(&driver
->clients
);
1136 /* Walk the adapters that are already present */
1137 mutex_lock(&core_lock
);
1138 bus_for_each_dev(&i2c_bus_type
, NULL
, driver
, __process_new_driver
);
1139 mutex_unlock(&core_lock
);
1143 EXPORT_SYMBOL(i2c_register_driver
);
1145 static int __process_removed_driver(struct device
*dev
, void *data
)
1147 if (dev
->type
!= &i2c_adapter_type
)
1149 return i2c_do_del_adapter(data
, to_i2c_adapter(dev
));
1153 * i2c_del_driver - unregister I2C driver
1154 * @driver: the driver being unregistered
1155 * Context: can sleep
1157 void i2c_del_driver(struct i2c_driver
*driver
)
1159 mutex_lock(&core_lock
);
1160 bus_for_each_dev(&i2c_bus_type
, NULL
, driver
, __process_removed_driver
);
1161 mutex_unlock(&core_lock
);
1163 driver_unregister(&driver
->driver
);
1164 pr_debug("i2c-core: driver [%s] unregistered\n", driver
->driver
.name
);
1166 EXPORT_SYMBOL(i2c_del_driver
);
1168 /* ------------------------------------------------------------------------- */
1171 * i2c_use_client - increments the reference count of the i2c client structure
1172 * @client: the client being referenced
1174 * Each live reference to a client should be refcounted. The driver model does
1175 * that automatically as part of driver binding, so that most drivers don't
1176 * need to do this explicitly: they hold a reference until they're unbound
1179 * A pointer to the client with the incremented reference counter is returned.
1181 struct i2c_client
*i2c_use_client(struct i2c_client
*client
)
1183 if (client
&& get_device(&client
->dev
))
1187 EXPORT_SYMBOL(i2c_use_client
);
1190 * i2c_release_client - release a use of the i2c client structure
1191 * @client: the client being no longer referenced
1193 * Must be called when a user of a client is finished with it.
1195 void i2c_release_client(struct i2c_client
*client
)
1198 put_device(&client
->dev
);
1200 EXPORT_SYMBOL(i2c_release_client
);
1202 struct i2c_cmd_arg
{
1207 static int i2c_cmd(struct device
*dev
, void *_arg
)
1209 struct i2c_client
*client
= i2c_verify_client(dev
);
1210 struct i2c_cmd_arg
*arg
= _arg
;
1212 if (client
&& client
->driver
&& client
->driver
->command
)
1213 client
->driver
->command(client
, arg
->cmd
, arg
->arg
);
1217 void i2c_clients_command(struct i2c_adapter
*adap
, unsigned int cmd
, void *arg
)
1219 struct i2c_cmd_arg cmd_arg
;
1223 device_for_each_child(&adap
->dev
, &cmd_arg
, i2c_cmd
);
1225 EXPORT_SYMBOL(i2c_clients_command
);
1227 static int __init
i2c_init(void)
1231 retval
= bus_register(&i2c_bus_type
);
1234 #ifdef CONFIG_I2C_COMPAT
1235 i2c_adapter_compat_class
= class_compat_register("i2c-adapter");
1236 if (!i2c_adapter_compat_class
) {
1241 retval
= i2c_add_driver(&dummy_driver
);
1247 #ifdef CONFIG_I2C_COMPAT
1248 class_compat_unregister(i2c_adapter_compat_class
);
1251 bus_unregister(&i2c_bus_type
);
1255 static void __exit
i2c_exit(void)
1257 i2c_del_driver(&dummy_driver
);
1258 #ifdef CONFIG_I2C_COMPAT
1259 class_compat_unregister(i2c_adapter_compat_class
);
1261 bus_unregister(&i2c_bus_type
);
1264 /* We must initialize early, because some subsystems register i2c drivers
1265 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1267 postcore_initcall(i2c_init
);
1268 module_exit(i2c_exit
);
1270 /* ----------------------------------------------------
1271 * the functional interface to the i2c busses.
1272 * ----------------------------------------------------
1276 * i2c_transfer - execute a single or combined I2C message
1277 * @adap: Handle to I2C bus
1278 * @msgs: One or more messages to execute before STOP is issued to
1279 * terminate the operation; each message begins with a START.
1280 * @num: Number of messages to be executed.
1282 * Returns negative errno, else the number of messages executed.
1284 * Note that there is no requirement that each message be sent to
1285 * the same slave address, although that is the most common model.
1287 int i2c_transfer(struct i2c_adapter
*adap
, struct i2c_msg
*msgs
, int num
)
1289 unsigned long orig_jiffies
;
1292 /* REVISIT the fault reporting model here is weak:
1294 * - When we get an error after receiving N bytes from a slave,
1295 * there is no way to report "N".
1297 * - When we get a NAK after transmitting N bytes to a slave,
1298 * there is no way to report "N" ... or to let the master
1299 * continue executing the rest of this combined message, if
1300 * that's the appropriate response.
1302 * - When for example "num" is two and we successfully complete
1303 * the first message but get an error part way through the
1304 * second, it's unclear whether that should be reported as
1305 * one (discarding status on the second message) or errno
1306 * (discarding status on the first one).
1309 if (adap
->algo
->master_xfer
) {
1311 for (ret
= 0; ret
< num
; ret
++) {
1312 dev_dbg(&adap
->dev
, "master_xfer[%d] %c, addr=0x%02x, "
1313 "len=%d%s\n", ret
, (msgs
[ret
].flags
& I2C_M_RD
)
1314 ? 'R' : 'W', msgs
[ret
].addr
, msgs
[ret
].len
,
1315 (msgs
[ret
].flags
& I2C_M_RECV_LEN
) ? "+" : "");
1319 if (in_atomic() || irqs_disabled()) {
1320 ret
= i2c_trylock_adapter(adap
);
1322 /* I2C activity is ongoing. */
1325 i2c_lock_adapter(adap
);
1328 /* Retry automatically on arbitration loss */
1329 orig_jiffies
= jiffies
;
1330 for (ret
= 0, try = 0; try <= adap
->retries
; try++) {
1331 ret
= adap
->algo
->master_xfer(adap
, msgs
, num
);
1334 if (time_after(jiffies
, orig_jiffies
+ adap
->timeout
))
1337 i2c_unlock_adapter(adap
);
1341 dev_dbg(&adap
->dev
, "I2C level transfers not supported\n");
1345 EXPORT_SYMBOL(i2c_transfer
);
1348 * i2c_master_send - issue a single I2C message in master transmit mode
1349 * @client: Handle to slave device
1350 * @buf: Data that will be written to the slave
1351 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1353 * Returns negative errno, or else the number of bytes written.
1355 int i2c_master_send(const struct i2c_client
*client
, const char *buf
, int count
)
1358 struct i2c_adapter
*adap
= client
->adapter
;
1361 msg
.addr
= client
->addr
;
1362 msg
.flags
= client
->flags
& I2C_M_TEN
;
1364 msg
.buf
= (char *)buf
;
1366 ret
= i2c_transfer(adap
, &msg
, 1);
1368 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1369 transmitted, else error code. */
1370 return (ret
== 1) ? count
: ret
;
1372 EXPORT_SYMBOL(i2c_master_send
);
1375 * i2c_master_recv - issue a single I2C message in master receive mode
1376 * @client: Handle to slave device
1377 * @buf: Where to store data read from slave
1378 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1380 * Returns negative errno, or else the number of bytes read.
1382 int i2c_master_recv(const struct i2c_client
*client
, char *buf
, int count
)
1384 struct i2c_adapter
*adap
= client
->adapter
;
1388 msg
.addr
= client
->addr
;
1389 msg
.flags
= client
->flags
& I2C_M_TEN
;
1390 msg
.flags
|= I2C_M_RD
;
1394 ret
= i2c_transfer(adap
, &msg
, 1);
1396 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1397 transmitted, else error code. */
1398 return (ret
== 1) ? count
: ret
;
1400 EXPORT_SYMBOL(i2c_master_recv
);
1402 /* ----------------------------------------------------
1403 * the i2c address scanning function
1404 * Will not work for 10-bit addresses!
1405 * ----------------------------------------------------
1409 * Legacy default probe function, mostly relevant for SMBus. The default
1410 * probe method is a quick write, but it is known to corrupt the 24RF08
1411 * EEPROMs due to a state machine bug, and could also irreversibly
1412 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1413 * we use a short byte read instead. Also, some bus drivers don't implement
1414 * quick write, so we fallback to a byte read in that case too.
1415 * On x86, there is another special case for FSC hardware monitoring chips,
1416 * which want regular byte reads (address 0x73.) Fortunately, these are the
1417 * only known chips using this I2C address on PC hardware.
1418 * Returns 1 if probe succeeded, 0 if not.
1420 static int i2c_default_probe(struct i2c_adapter
*adap
, unsigned short addr
)
1423 union i2c_smbus_data dummy
;
1426 if (addr
== 0x73 && (adap
->class & I2C_CLASS_HWMON
)
1427 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE_DATA
))
1428 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
1429 I2C_SMBUS_BYTE_DATA
, &dummy
);
1432 if (!((addr
& ~0x07) == 0x30 || (addr
& ~0x0f) == 0x50)
1433 && i2c_check_functionality(adap
, I2C_FUNC_SMBUS_QUICK
))
1434 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_WRITE
, 0,
1435 I2C_SMBUS_QUICK
, NULL
);
1436 else if (i2c_check_functionality(adap
, I2C_FUNC_SMBUS_READ_BYTE
))
1437 err
= i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
1438 I2C_SMBUS_BYTE
, &dummy
);
1440 dev_warn(&adap
->dev
, "No suitable probing method supported\n");
1447 static int i2c_detect_address(struct i2c_client
*temp_client
,
1448 struct i2c_driver
*driver
)
1450 struct i2c_board_info info
;
1451 struct i2c_adapter
*adapter
= temp_client
->adapter
;
1452 int addr
= temp_client
->addr
;
1455 /* Make sure the address is valid */
1456 err
= i2c_check_addr_validity(addr
);
1458 dev_warn(&adapter
->dev
, "Invalid probe address 0x%02x\n",
1463 /* Skip if already in use */
1464 if (i2c_check_addr_busy(adapter
, addr
))
1467 /* Make sure there is something at this address */
1468 if (!i2c_default_probe(adapter
, addr
))
1471 /* Finally call the custom detection function */
1472 memset(&info
, 0, sizeof(struct i2c_board_info
));
1474 err
= driver
->detect(temp_client
, &info
);
1476 /* -ENODEV is returned if the detection fails. We catch it
1477 here as this isn't an error. */
1478 return err
== -ENODEV
? 0 : err
;
1481 /* Consistency check */
1482 if (info
.type
[0] == '\0') {
1483 dev_err(&adapter
->dev
, "%s detection function provided "
1484 "no name for 0x%x\n", driver
->driver
.name
,
1487 struct i2c_client
*client
;
1489 /* Detection succeeded, instantiate the device */
1490 dev_dbg(&adapter
->dev
, "Creating %s at 0x%02x\n",
1491 info
.type
, info
.addr
);
1492 client
= i2c_new_device(adapter
, &info
);
1494 list_add_tail(&client
->detected
, &driver
->clients
);
1496 dev_err(&adapter
->dev
, "Failed creating %s at 0x%02x\n",
1497 info
.type
, info
.addr
);
1502 static int i2c_detect(struct i2c_adapter
*adapter
, struct i2c_driver
*driver
)
1504 const unsigned short *address_list
;
1505 struct i2c_client
*temp_client
;
1507 int adap_id
= i2c_adapter_id(adapter
);
1509 address_list
= driver
->address_list
;
1510 if (!driver
->detect
|| !address_list
)
1513 /* Stop here if the classes do not match */
1514 if (!(adapter
->class & driver
->class))
1517 /* Set up a temporary client to help detect callback */
1518 temp_client
= kzalloc(sizeof(struct i2c_client
), GFP_KERNEL
);
1521 temp_client
->adapter
= adapter
;
1523 for (i
= 0; address_list
[i
] != I2C_CLIENT_END
; i
+= 1) {
1524 dev_dbg(&adapter
->dev
, "found normal entry for adapter %d, "
1525 "addr 0x%02x\n", adap_id
, address_list
[i
]);
1526 temp_client
->addr
= address_list
[i
];
1527 err
= i2c_detect_address(temp_client
, driver
);
1536 int i2c_probe_func_quick_read(struct i2c_adapter
*adap
, unsigned short addr
)
1538 return i2c_smbus_xfer(adap
, addr
, 0, I2C_SMBUS_READ
, 0,
1539 I2C_SMBUS_QUICK
, NULL
) >= 0;
1541 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read
);
1544 i2c_new_probed_device(struct i2c_adapter
*adap
,
1545 struct i2c_board_info
*info
,
1546 unsigned short const *addr_list
,
1547 int (*probe
)(struct i2c_adapter
*, unsigned short addr
))
1552 probe
= i2c_default_probe
;
1554 for (i
= 0; addr_list
[i
] != I2C_CLIENT_END
; i
++) {
1555 /* Check address validity */
1556 if (i2c_check_addr_validity(addr_list
[i
]) < 0) {
1557 dev_warn(&adap
->dev
, "Invalid 7-bit address "
1558 "0x%02x\n", addr_list
[i
]);
1562 /* Check address availability */
1563 if (i2c_check_addr_busy(adap
, addr_list
[i
])) {
1564 dev_dbg(&adap
->dev
, "Address 0x%02x already in "
1565 "use, not probing\n", addr_list
[i
]);
1569 /* Test address responsiveness */
1570 if (probe(adap
, addr_list
[i
]))
1574 if (addr_list
[i
] == I2C_CLIENT_END
) {
1575 dev_dbg(&adap
->dev
, "Probing failed, no device found\n");
1579 info
->addr
= addr_list
[i
];
1580 return i2c_new_device(adap
, info
);
1582 EXPORT_SYMBOL_GPL(i2c_new_probed_device
);
1584 struct i2c_adapter
*i2c_get_adapter(int nr
)
1586 struct i2c_adapter
*adapter
;
1588 mutex_lock(&core_lock
);
1589 adapter
= idr_find(&i2c_adapter_idr
, nr
);
1590 if (adapter
&& !try_module_get(adapter
->owner
))
1593 mutex_unlock(&core_lock
);
1596 EXPORT_SYMBOL(i2c_get_adapter
);
1598 void i2c_put_adapter(struct i2c_adapter
*adap
)
1600 module_put(adap
->owner
);
1602 EXPORT_SYMBOL(i2c_put_adapter
);
1604 /* The SMBus parts */
1606 #define POLY (0x1070U << 3)
1607 static u8
crc8(u16 data
)
1611 for (i
= 0; i
< 8; i
++) {
1616 return (u8
)(data
>> 8);
1619 /* Incremental CRC8 over count bytes in the array pointed to by p */
1620 static u8
i2c_smbus_pec(u8 crc
, u8
*p
, size_t count
)
1624 for (i
= 0; i
< count
; i
++)
1625 crc
= crc8((crc
^ p
[i
]) << 8);
1629 /* Assume a 7-bit address, which is reasonable for SMBus */
1630 static u8
i2c_smbus_msg_pec(u8 pec
, struct i2c_msg
*msg
)
1632 /* The address will be sent first */
1633 u8 addr
= (msg
->addr
<< 1) | !!(msg
->flags
& I2C_M_RD
);
1634 pec
= i2c_smbus_pec(pec
, &addr
, 1);
1636 /* The data buffer follows */
1637 return i2c_smbus_pec(pec
, msg
->buf
, msg
->len
);
1640 /* Used for write only transactions */
1641 static inline void i2c_smbus_add_pec(struct i2c_msg
*msg
)
1643 msg
->buf
[msg
->len
] = i2c_smbus_msg_pec(0, msg
);
1647 /* Return <0 on CRC error
1648 If there was a write before this read (most cases) we need to take the
1649 partial CRC from the write part into account.
1650 Note that this function does modify the message (we need to decrease the
1651 message length to hide the CRC byte from the caller). */
1652 static int i2c_smbus_check_pec(u8 cpec
, struct i2c_msg
*msg
)
1654 u8 rpec
= msg
->buf
[--msg
->len
];
1655 cpec
= i2c_smbus_msg_pec(cpec
, msg
);
1658 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1666 * i2c_smbus_read_byte - SMBus "receive byte" protocol
1667 * @client: Handle to slave device
1669 * This executes the SMBus "receive byte" protocol, returning negative errno
1670 * else the byte received from the device.
1672 s32
i2c_smbus_read_byte(const struct i2c_client
*client
)
1674 union i2c_smbus_data data
;
1677 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1679 I2C_SMBUS_BYTE
, &data
);
1680 return (status
< 0) ? status
: data
.byte
;
1682 EXPORT_SYMBOL(i2c_smbus_read_byte
);
1685 * i2c_smbus_write_byte - SMBus "send byte" protocol
1686 * @client: Handle to slave device
1687 * @value: Byte to be sent
1689 * This executes the SMBus "send byte" protocol, returning negative errno
1690 * else zero on success.
1692 s32
i2c_smbus_write_byte(const struct i2c_client
*client
, u8 value
)
1694 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1695 I2C_SMBUS_WRITE
, value
, I2C_SMBUS_BYTE
, NULL
);
1697 EXPORT_SYMBOL(i2c_smbus_write_byte
);
1700 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
1701 * @client: Handle to slave device
1702 * @command: Byte interpreted by slave
1704 * This executes the SMBus "read byte" protocol, returning negative errno
1705 * else a data byte received from the device.
1707 s32
i2c_smbus_read_byte_data(const struct i2c_client
*client
, u8 command
)
1709 union i2c_smbus_data data
;
1712 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1713 I2C_SMBUS_READ
, command
,
1714 I2C_SMBUS_BYTE_DATA
, &data
);
1715 return (status
< 0) ? status
: data
.byte
;
1717 EXPORT_SYMBOL(i2c_smbus_read_byte_data
);
1720 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
1721 * @client: Handle to slave device
1722 * @command: Byte interpreted by slave
1723 * @value: Byte being written
1725 * This executes the SMBus "write byte" protocol, returning negative errno
1726 * else zero on success.
1728 s32
i2c_smbus_write_byte_data(const struct i2c_client
*client
, u8 command
,
1731 union i2c_smbus_data data
;
1733 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1734 I2C_SMBUS_WRITE
, command
,
1735 I2C_SMBUS_BYTE_DATA
, &data
);
1737 EXPORT_SYMBOL(i2c_smbus_write_byte_data
);
1740 * i2c_smbus_read_word_data - SMBus "read word" protocol
1741 * @client: Handle to slave device
1742 * @command: Byte interpreted by slave
1744 * This executes the SMBus "read word" protocol, returning negative errno
1745 * else a 16-bit unsigned "word" received from the device.
1747 s32
i2c_smbus_read_word_data(const struct i2c_client
*client
, u8 command
)
1749 union i2c_smbus_data data
;
1752 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1753 I2C_SMBUS_READ
, command
,
1754 I2C_SMBUS_WORD_DATA
, &data
);
1755 return (status
< 0) ? status
: data
.word
;
1757 EXPORT_SYMBOL(i2c_smbus_read_word_data
);
1760 * i2c_smbus_write_word_data - SMBus "write word" protocol
1761 * @client: Handle to slave device
1762 * @command: Byte interpreted by slave
1763 * @value: 16-bit "word" being written
1765 * This executes the SMBus "write word" protocol, returning negative errno
1766 * else zero on success.
1768 s32
i2c_smbus_write_word_data(const struct i2c_client
*client
, u8 command
,
1771 union i2c_smbus_data data
;
1773 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1774 I2C_SMBUS_WRITE
, command
,
1775 I2C_SMBUS_WORD_DATA
, &data
);
1777 EXPORT_SYMBOL(i2c_smbus_write_word_data
);
1780 * i2c_smbus_process_call - SMBus "process call" protocol
1781 * @client: Handle to slave device
1782 * @command: Byte interpreted by slave
1783 * @value: 16-bit "word" being written
1785 * This executes the SMBus "process call" protocol, returning negative errno
1786 * else a 16-bit unsigned "word" received from the device.
1788 s32
i2c_smbus_process_call(const struct i2c_client
*client
, u8 command
,
1791 union i2c_smbus_data data
;
1795 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1796 I2C_SMBUS_WRITE
, command
,
1797 I2C_SMBUS_PROC_CALL
, &data
);
1798 return (status
< 0) ? status
: data
.word
;
1800 EXPORT_SYMBOL(i2c_smbus_process_call
);
1803 * i2c_smbus_read_block_data - SMBus "block read" protocol
1804 * @client: Handle to slave device
1805 * @command: Byte interpreted by slave
1806 * @values: Byte array into which data will be read; big enough to hold
1807 * the data returned by the slave. SMBus allows at most 32 bytes.
1809 * This executes the SMBus "block read" protocol, returning negative errno
1810 * else the number of data bytes in the slave's response.
1812 * Note that using this function requires that the client's adapter support
1813 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1814 * support this; its emulation through I2C messaging relies on a specific
1815 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1817 s32
i2c_smbus_read_block_data(const struct i2c_client
*client
, u8 command
,
1820 union i2c_smbus_data data
;
1823 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1824 I2C_SMBUS_READ
, command
,
1825 I2C_SMBUS_BLOCK_DATA
, &data
);
1829 memcpy(values
, &data
.block
[1], data
.block
[0]);
1830 return data
.block
[0];
1832 EXPORT_SYMBOL(i2c_smbus_read_block_data
);
1835 * i2c_smbus_write_block_data - SMBus "block write" protocol
1836 * @client: Handle to slave device
1837 * @command: Byte interpreted by slave
1838 * @length: Size of data block; SMBus allows at most 32 bytes
1839 * @values: Byte array which will be written.
1841 * This executes the SMBus "block write" protocol, returning negative errno
1842 * else zero on success.
1844 s32
i2c_smbus_write_block_data(const struct i2c_client
*client
, u8 command
,
1845 u8 length
, const u8
*values
)
1847 union i2c_smbus_data data
;
1849 if (length
> I2C_SMBUS_BLOCK_MAX
)
1850 length
= I2C_SMBUS_BLOCK_MAX
;
1851 data
.block
[0] = length
;
1852 memcpy(&data
.block
[1], values
, length
);
1853 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1854 I2C_SMBUS_WRITE
, command
,
1855 I2C_SMBUS_BLOCK_DATA
, &data
);
1857 EXPORT_SYMBOL(i2c_smbus_write_block_data
);
1859 /* Returns the number of read bytes */
1860 s32
i2c_smbus_read_i2c_block_data(const struct i2c_client
*client
, u8 command
,
1861 u8 length
, u8
*values
)
1863 union i2c_smbus_data data
;
1866 if (length
> I2C_SMBUS_BLOCK_MAX
)
1867 length
= I2C_SMBUS_BLOCK_MAX
;
1868 data
.block
[0] = length
;
1869 status
= i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1870 I2C_SMBUS_READ
, command
,
1871 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
1875 memcpy(values
, &data
.block
[1], data
.block
[0]);
1876 return data
.block
[0];
1878 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data
);
1880 s32
i2c_smbus_write_i2c_block_data(const struct i2c_client
*client
, u8 command
,
1881 u8 length
, const u8
*values
)
1883 union i2c_smbus_data data
;
1885 if (length
> I2C_SMBUS_BLOCK_MAX
)
1886 length
= I2C_SMBUS_BLOCK_MAX
;
1887 data
.block
[0] = length
;
1888 memcpy(data
.block
+ 1, values
, length
);
1889 return i2c_smbus_xfer(client
->adapter
, client
->addr
, client
->flags
,
1890 I2C_SMBUS_WRITE
, command
,
1891 I2C_SMBUS_I2C_BLOCK_DATA
, &data
);
1893 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data
);
1895 /* Simulate a SMBus command using the i2c protocol
1896 No checking of parameters is done! */
1897 static s32
i2c_smbus_xfer_emulated(struct i2c_adapter
*adapter
, u16 addr
,
1898 unsigned short flags
,
1899 char read_write
, u8 command
, int size
,
1900 union i2c_smbus_data
*data
)
1902 /* So we need to generate a series of msgs. In the case of writing, we
1903 need to use only one message; when reading, we need two. We initialize
1904 most things with sane defaults, to keep the code below somewhat
1906 unsigned char msgbuf0
[I2C_SMBUS_BLOCK_MAX
+3];
1907 unsigned char msgbuf1
[I2C_SMBUS_BLOCK_MAX
+2];
1908 int num
= read_write
== I2C_SMBUS_READ
? 2 : 1;
1909 struct i2c_msg msg
[2] = { { addr
, flags
, 1, msgbuf0
},
1910 { addr
, flags
| I2C_M_RD
, 0, msgbuf1
}
1916 msgbuf0
[0] = command
;
1918 case I2C_SMBUS_QUICK
:
1920 /* Special case: The read/write field is used as data */
1921 msg
[0].flags
= flags
| (read_write
== I2C_SMBUS_READ
?
1925 case I2C_SMBUS_BYTE
:
1926 if (read_write
== I2C_SMBUS_READ
) {
1927 /* Special case: only a read! */
1928 msg
[0].flags
= I2C_M_RD
| flags
;
1932 case I2C_SMBUS_BYTE_DATA
:
1933 if (read_write
== I2C_SMBUS_READ
)
1937 msgbuf0
[1] = data
->byte
;
1940 case I2C_SMBUS_WORD_DATA
:
1941 if (read_write
== I2C_SMBUS_READ
)
1945 msgbuf0
[1] = data
->word
& 0xff;
1946 msgbuf0
[2] = data
->word
>> 8;
1949 case I2C_SMBUS_PROC_CALL
:
1950 num
= 2; /* Special case */
1951 read_write
= I2C_SMBUS_READ
;
1954 msgbuf0
[1] = data
->word
& 0xff;
1955 msgbuf0
[2] = data
->word
>> 8;
1957 case I2C_SMBUS_BLOCK_DATA
:
1958 if (read_write
== I2C_SMBUS_READ
) {
1959 msg
[1].flags
|= I2C_M_RECV_LEN
;
1960 msg
[1].len
= 1; /* block length will be added by
1961 the underlying bus driver */
1963 msg
[0].len
= data
->block
[0] + 2;
1964 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 2) {
1965 dev_err(&adapter
->dev
,
1966 "Invalid block write size %d\n",
1970 for (i
= 1; i
< msg
[0].len
; i
++)
1971 msgbuf0
[i
] = data
->block
[i
-1];
1974 case I2C_SMBUS_BLOCK_PROC_CALL
:
1975 num
= 2; /* Another special case */
1976 read_write
= I2C_SMBUS_READ
;
1977 if (data
->block
[0] > I2C_SMBUS_BLOCK_MAX
) {
1978 dev_err(&adapter
->dev
,
1979 "Invalid block write size %d\n",
1983 msg
[0].len
= data
->block
[0] + 2;
1984 for (i
= 1; i
< msg
[0].len
; i
++)
1985 msgbuf0
[i
] = data
->block
[i
-1];
1986 msg
[1].flags
|= I2C_M_RECV_LEN
;
1987 msg
[1].len
= 1; /* block length will be added by
1988 the underlying bus driver */
1990 case I2C_SMBUS_I2C_BLOCK_DATA
:
1991 if (read_write
== I2C_SMBUS_READ
) {
1992 msg
[1].len
= data
->block
[0];
1994 msg
[0].len
= data
->block
[0] + 1;
1995 if (msg
[0].len
> I2C_SMBUS_BLOCK_MAX
+ 1) {
1996 dev_err(&adapter
->dev
,
1997 "Invalid block write size %d\n",
2001 for (i
= 1; i
<= data
->block
[0]; i
++)
2002 msgbuf0
[i
] = data
->block
[i
];
2006 dev_err(&adapter
->dev
, "Unsupported transaction %d\n", size
);
2010 i
= ((flags
& I2C_CLIENT_PEC
) && size
!= I2C_SMBUS_QUICK
2011 && size
!= I2C_SMBUS_I2C_BLOCK_DATA
);
2013 /* Compute PEC if first message is a write */
2014 if (!(msg
[0].flags
& I2C_M_RD
)) {
2015 if (num
== 1) /* Write only */
2016 i2c_smbus_add_pec(&msg
[0]);
2017 else /* Write followed by read */
2018 partial_pec
= i2c_smbus_msg_pec(0, &msg
[0]);
2020 /* Ask for PEC if last message is a read */
2021 if (msg
[num
-1].flags
& I2C_M_RD
)
2025 status
= i2c_transfer(adapter
, msg
, num
);
2029 /* Check PEC if last message is a read */
2030 if (i
&& (msg
[num
-1].flags
& I2C_M_RD
)) {
2031 status
= i2c_smbus_check_pec(partial_pec
, &msg
[num
-1]);
2036 if (read_write
== I2C_SMBUS_READ
)
2038 case I2C_SMBUS_BYTE
:
2039 data
->byte
= msgbuf0
[0];
2041 case I2C_SMBUS_BYTE_DATA
:
2042 data
->byte
= msgbuf1
[0];
2044 case I2C_SMBUS_WORD_DATA
:
2045 case I2C_SMBUS_PROC_CALL
:
2046 data
->word
= msgbuf1
[0] | (msgbuf1
[1] << 8);
2048 case I2C_SMBUS_I2C_BLOCK_DATA
:
2049 for (i
= 0; i
< data
->block
[0]; i
++)
2050 data
->block
[i
+1] = msgbuf1
[i
];
2052 case I2C_SMBUS_BLOCK_DATA
:
2053 case I2C_SMBUS_BLOCK_PROC_CALL
:
2054 for (i
= 0; i
< msgbuf1
[0] + 1; i
++)
2055 data
->block
[i
] = msgbuf1
[i
];
2062 * i2c_smbus_xfer - execute SMBus protocol operations
2063 * @adapter: Handle to I2C bus
2064 * @addr: Address of SMBus slave on that bus
2065 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2066 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2067 * @command: Byte interpreted by slave, for protocols which use such bytes
2068 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2069 * @data: Data to be read or written
2071 * This executes an SMBus protocol operation, and returns a negative
2072 * errno code else zero on success.
2074 s32
i2c_smbus_xfer(struct i2c_adapter
*adapter
, u16 addr
, unsigned short flags
,
2075 char read_write
, u8 command
, int protocol
,
2076 union i2c_smbus_data
*data
)
2078 unsigned long orig_jiffies
;
2082 flags
&= I2C_M_TEN
| I2C_CLIENT_PEC
;
2084 if (adapter
->algo
->smbus_xfer
) {
2085 i2c_lock_adapter(adapter
);
2087 /* Retry automatically on arbitration loss */
2088 orig_jiffies
= jiffies
;
2089 for (res
= 0, try = 0; try <= adapter
->retries
; try++) {
2090 res
= adapter
->algo
->smbus_xfer(adapter
, addr
, flags
,
2091 read_write
, command
,
2095 if (time_after(jiffies
,
2096 orig_jiffies
+ adapter
->timeout
))
2099 i2c_unlock_adapter(adapter
);
2101 res
= i2c_smbus_xfer_emulated(adapter
, addr
, flags
, read_write
,
2102 command
, protocol
, data
);
2106 EXPORT_SYMBOL(i2c_smbus_xfer
);
2108 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2109 MODULE_DESCRIPTION("I2C-Bus main module");
2110 MODULE_LICENSE("GPL");