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> */
25 #include <linux/module.h>
26 #include <linux/kernel.h>
27 #include <linux/errno.h>
28 #include <linux/slab.h>
29 #include <linux/i2c.h>
30 #include <linux/init.h>
31 #include <linux/idr.h>
32 #include <linux/mutex.h>
33 #include <linux/of_i2c.h>
34 #include <linux/of_device.h>
35 #include <linux/completion.h>
36 #include <linux/hardirq.h>
37 #include <linux/irqflags.h>
38 #include <linux/rwsem.h>
39 #include <linux/pm_runtime.h>
40 #include <asm/uaccess.h>
45 /* core_lock protects i2c_adapter_idr, and guarantees
46 that device detection, deletion of detected devices, and attach_adapter
47 and detach_adapter calls are serialized */
48 static DEFINE_MUTEX(core_lock);
49 static DEFINE_IDR(i2c_adapter_idr);
51 static struct device_type i2c_client_type;
52 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
54 /* ------------------------------------------------------------------------- */
56 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
57 const struct i2c_client *client)
60 if (strcmp(client->name, id->name) == 0)
67 static int i2c_device_match(struct device *dev, struct device_driver *drv)
69 struct i2c_client *client = i2c_verify_client(dev);
70 struct i2c_driver *driver;
75 /* Attempt an OF style match */
76 if (of_driver_match_device(dev, drv))
79 driver = to_i2c_driver(drv);
80 /* match on an id table if there is one */
82 return i2c_match_id(driver->id_table, client) != NULL;
89 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
90 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
92 struct i2c_client *client = to_i2c_client(dev);
94 if (add_uevent_var(env, "MODALIAS=%s%s",
95 I2C_MODULE_PREFIX, client->name))
97 dev_dbg(dev, "uevent\n");
102 #define i2c_device_uevent NULL
103 #endif /* CONFIG_HOTPLUG */
105 static int i2c_device_probe(struct device *dev)
107 struct i2c_client *client = i2c_verify_client(dev);
108 struct i2c_driver *driver;
114 driver = to_i2c_driver(dev->driver);
115 if (!driver->probe || !driver->id_table)
117 client->driver = driver;
118 if (!device_can_wakeup(&client->dev))
119 device_init_wakeup(&client->dev,
120 client->flags & I2C_CLIENT_WAKE);
121 dev_dbg(dev, "probe\n");
123 status = driver->probe(client, i2c_match_id(driver->id_table, client));
125 client->driver = NULL;
126 i2c_set_clientdata(client, NULL);
131 static int i2c_device_remove(struct device *dev)
133 struct i2c_client *client = i2c_verify_client(dev);
134 struct i2c_driver *driver;
137 if (!client || !dev->driver)
140 driver = to_i2c_driver(dev->driver);
141 if (driver->remove) {
142 dev_dbg(dev, "remove\n");
143 status = driver->remove(client);
149 client->driver = NULL;
150 i2c_set_clientdata(client, NULL);
155 static void i2c_device_shutdown(struct device *dev)
157 struct i2c_client *client = i2c_verify_client(dev);
158 struct i2c_driver *driver;
160 if (!client || !dev->driver)
162 driver = to_i2c_driver(dev->driver);
163 if (driver->shutdown)
164 driver->shutdown(client);
167 #ifdef CONFIG_PM_SLEEP
168 static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
170 struct i2c_client *client = i2c_verify_client(dev);
171 struct i2c_driver *driver;
173 if (!client || !dev->driver)
175 driver = to_i2c_driver(dev->driver);
176 if (!driver->suspend)
178 return driver->suspend(client, mesg);
181 static int i2c_legacy_resume(struct device *dev)
183 struct i2c_client *client = i2c_verify_client(dev);
184 struct i2c_driver *driver;
186 if (!client || !dev->driver)
188 driver = to_i2c_driver(dev->driver);
191 return driver->resume(client);
194 static int i2c_device_pm_suspend(struct device *dev)
196 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
198 if (pm_runtime_suspended(dev))
202 return pm->suspend ? pm->suspend(dev) : 0;
204 return i2c_legacy_suspend(dev, PMSG_SUSPEND);
207 static int i2c_device_pm_resume(struct device *dev)
209 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
213 ret = pm->resume ? pm->resume(dev) : 0;
215 ret = i2c_legacy_resume(dev);
218 pm_runtime_disable(dev);
219 pm_runtime_set_active(dev);
220 pm_runtime_enable(dev);
226 static int i2c_device_pm_freeze(struct device *dev)
228 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
230 if (pm_runtime_suspended(dev))
234 return pm->freeze ? pm->freeze(dev) : 0;
236 return i2c_legacy_suspend(dev, PMSG_FREEZE);
239 static int i2c_device_pm_thaw(struct device *dev)
241 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
243 if (pm_runtime_suspended(dev))
247 return pm->thaw ? pm->thaw(dev) : 0;
249 return i2c_legacy_resume(dev);
252 static int i2c_device_pm_poweroff(struct device *dev)
254 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
256 if (pm_runtime_suspended(dev))
260 return pm->poweroff ? pm->poweroff(dev) : 0;
262 return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
265 static int i2c_device_pm_restore(struct device *dev)
267 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
271 ret = pm->restore ? pm->restore(dev) : 0;
273 ret = i2c_legacy_resume(dev);
276 pm_runtime_disable(dev);
277 pm_runtime_set_active(dev);
278 pm_runtime_enable(dev);
283 #else /* !CONFIG_PM_SLEEP */
284 #define i2c_device_pm_suspend NULL
285 #define i2c_device_pm_resume NULL
286 #define i2c_device_pm_freeze NULL
287 #define i2c_device_pm_thaw NULL
288 #define i2c_device_pm_poweroff NULL
289 #define i2c_device_pm_restore NULL
290 #endif /* !CONFIG_PM_SLEEP */
292 static void i2c_client_dev_release(struct device *dev)
294 kfree(to_i2c_client(dev));
298 show_name(struct device *dev, struct device_attribute *attr, char *buf)
300 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
301 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
305 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
307 struct i2c_client *client = to_i2c_client(dev);
308 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
311 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
312 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
314 static struct attribute *i2c_dev_attrs[] = {
316 /* modalias helps coldplug: modprobe $(cat .../modalias) */
317 &dev_attr_modalias.attr,
321 static struct attribute_group i2c_dev_attr_group = {
322 .attrs = i2c_dev_attrs,
325 static const struct attribute_group *i2c_dev_attr_groups[] = {
330 static const struct dev_pm_ops i2c_device_pm_ops = {
331 .suspend = i2c_device_pm_suspend,
332 .resume = i2c_device_pm_resume,
333 .freeze = i2c_device_pm_freeze,
334 .thaw = i2c_device_pm_thaw,
335 .poweroff = i2c_device_pm_poweroff,
336 .restore = i2c_device_pm_restore,
338 pm_generic_runtime_suspend,
339 pm_generic_runtime_resume,
340 pm_generic_runtime_idle
344 struct bus_type i2c_bus_type = {
346 .match = i2c_device_match,
347 .probe = i2c_device_probe,
348 .remove = i2c_device_remove,
349 .shutdown = i2c_device_shutdown,
350 .pm = &i2c_device_pm_ops,
352 EXPORT_SYMBOL_GPL(i2c_bus_type);
354 static struct device_type i2c_client_type = {
355 .groups = i2c_dev_attr_groups,
356 .uevent = i2c_device_uevent,
357 .release = i2c_client_dev_release,
362 * i2c_verify_client - return parameter as i2c_client, or NULL
363 * @dev: device, probably from some driver model iterator
365 * When traversing the driver model tree, perhaps using driver model
366 * iterators like @device_for_each_child(), you can't assume very much
367 * about the nodes you find. Use this function to avoid oopses caused
368 * by wrongly treating some non-I2C device as an i2c_client.
370 struct i2c_client *i2c_verify_client(struct device *dev)
372 return (dev->type == &i2c_client_type)
376 EXPORT_SYMBOL(i2c_verify_client);
379 /* This is a permissive address validity check, I2C address map constraints
380 * are purposedly not enforced, except for the general call address. */
381 static int i2c_check_client_addr_validity(const struct i2c_client *client)
383 if (client->flags & I2C_CLIENT_TEN) {
384 /* 10-bit address, all values are valid */
385 if (client->addr > 0x3ff)
388 /* 7-bit address, reject the general call address */
389 if (client->addr == 0x00 || client->addr > 0x7f)
395 /* And this is a strict address validity check, used when probing. If a
396 * device uses a reserved address, then it shouldn't be probed. 7-bit
397 * addressing is assumed, 10-bit address devices are rare and should be
398 * explicitly enumerated. */
399 static int i2c_check_addr_validity(unsigned short addr)
402 * Reserved addresses per I2C specification:
403 * 0x00 General call address / START byte
405 * 0x02 Reserved for different bus format
406 * 0x03 Reserved for future purposes
407 * 0x04-0x07 Hs-mode master code
408 * 0x78-0x7b 10-bit slave addressing
409 * 0x7c-0x7f Reserved for future purposes
411 if (addr < 0x08 || addr > 0x77)
416 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
418 struct i2c_client *client = i2c_verify_client(dev);
419 int addr = *(int *)addrp;
421 if (client && client->addr == addr)
426 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
428 return device_for_each_child(&adapter->dev, &addr,
429 __i2c_check_addr_busy);
433 * i2c_new_device - instantiate an i2c device
434 * @adap: the adapter managing the device
435 * @info: describes one I2C device; bus_num is ignored
438 * Create an i2c device. Binding is handled through driver model
439 * probe()/remove() methods. A driver may be bound to this device when we
440 * return from this function, or any later moment (e.g. maybe hotplugging will
441 * load the driver module). This call is not appropriate for use by mainboard
442 * initialization logic, which usually runs during an arch_initcall() long
443 * before any i2c_adapter could exist.
445 * This returns the new i2c client, which may be saved for later use with
446 * i2c_unregister_device(); or NULL to indicate an error.
449 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
451 struct i2c_client *client;
454 client = kzalloc(sizeof *client, GFP_KERNEL);
458 client->adapter = adap;
460 client->dev.platform_data = info->platform_data;
463 client->dev.archdata = *info->archdata;
465 client->flags = info->flags;
466 client->addr = info->addr;
467 client->irq = info->irq;
469 strlcpy(client->name, info->type, sizeof(client->name));
471 /* Check for address validity */
472 status = i2c_check_client_addr_validity(client);
474 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
475 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
479 /* Check for address business */
480 status = i2c_check_addr_busy(adap, client->addr);
484 client->dev.parent = &client->adapter->dev;
485 client->dev.bus = &i2c_bus_type;
486 client->dev.type = &i2c_client_type;
488 client->dev.of_node = info->of_node;
491 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
493 status = device_register(&client->dev);
497 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
498 client->name, dev_name(&client->dev));
503 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
504 "(%d)\n", client->name, client->addr, status);
509 EXPORT_SYMBOL_GPL(i2c_new_device);
513 * i2c_unregister_device - reverse effect of i2c_new_device()
514 * @client: value returned from i2c_new_device()
517 void i2c_unregister_device(struct i2c_client *client)
519 device_unregister(&client->dev);
521 EXPORT_SYMBOL_GPL(i2c_unregister_device);
524 static const struct i2c_device_id dummy_id[] = {
529 static int dummy_probe(struct i2c_client *client,
530 const struct i2c_device_id *id)
535 static int dummy_remove(struct i2c_client *client)
540 static struct i2c_driver dummy_driver = {
541 .driver.name = "dummy",
542 .probe = dummy_probe,
543 .remove = dummy_remove,
544 .id_table = dummy_id,
548 * i2c_new_dummy - return a new i2c device bound to a dummy driver
549 * @adapter: the adapter managing the device
550 * @address: seven bit address to be used
553 * This returns an I2C client bound to the "dummy" driver, intended for use
554 * with devices that consume multiple addresses. Examples of such chips
555 * include various EEPROMS (like 24c04 and 24c08 models).
557 * These dummy devices have two main uses. First, most I2C and SMBus calls
558 * except i2c_transfer() need a client handle; the dummy will be that handle.
559 * And second, this prevents the specified address from being bound to a
562 * This returns the new i2c client, which should be saved for later use with
563 * i2c_unregister_device(); or NULL to indicate an error.
565 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
567 struct i2c_board_info info = {
568 I2C_BOARD_INFO("dummy", address),
571 return i2c_new_device(adapter, &info);
573 EXPORT_SYMBOL_GPL(i2c_new_dummy);
575 /* ------------------------------------------------------------------------- */
577 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
579 static void i2c_adapter_dev_release(struct device *dev)
581 struct i2c_adapter *adap = to_i2c_adapter(dev);
582 complete(&adap->dev_released);
586 * Let users instantiate I2C devices through sysfs. This can be used when
587 * platform initialization code doesn't contain the proper data for
588 * whatever reason. Also useful for drivers that do device detection and
589 * detection fails, either because the device uses an unexpected address,
590 * or this is a compatible device with different ID register values.
592 * Parameter checking may look overzealous, but we really don't want
593 * the user to provide incorrect parameters.
596 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
597 const char *buf, size_t count)
599 struct i2c_adapter *adap = to_i2c_adapter(dev);
600 struct i2c_board_info info;
601 struct i2c_client *client;
605 dev_warn(dev, "The new_device interface is still experimental "
606 "and may change in a near future\n");
607 memset(&info, 0, sizeof(struct i2c_board_info));
609 blank = strchr(buf, ' ');
611 dev_err(dev, "%s: Missing parameters\n", "new_device");
614 if (blank - buf > I2C_NAME_SIZE - 1) {
615 dev_err(dev, "%s: Invalid device name\n", "new_device");
618 memcpy(info.type, buf, blank - buf);
620 /* Parse remaining parameters, reject extra parameters */
621 res = sscanf(++blank, "%hi%c", &info.addr, &end);
623 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
626 if (res > 1 && end != '\n') {
627 dev_err(dev, "%s: Extra parameters\n", "new_device");
631 client = i2c_new_device(adap, &info);
635 /* Keep track of the added device */
636 i2c_lock_adapter(adap);
637 list_add_tail(&client->detected, &adap->userspace_clients);
638 i2c_unlock_adapter(adap);
639 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
640 info.type, info.addr);
646 * And of course let the users delete the devices they instantiated, if
647 * they got it wrong. This interface can only be used to delete devices
648 * instantiated by i2c_sysfs_new_device above. This guarantees that we
649 * don't delete devices to which some kernel code still has references.
651 * Parameter checking may look overzealous, but we really don't want
652 * the user to delete the wrong device.
655 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
656 const char *buf, size_t count)
658 struct i2c_adapter *adap = to_i2c_adapter(dev);
659 struct i2c_client *client, *next;
664 /* Parse parameters, reject extra parameters */
665 res = sscanf(buf, "%hi%c", &addr, &end);
667 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
670 if (res > 1 && end != '\n') {
671 dev_err(dev, "%s: Extra parameters\n", "delete_device");
675 /* Make sure the device was added through sysfs */
677 i2c_lock_adapter(adap);
678 list_for_each_entry_safe(client, next, &adap->userspace_clients,
680 if (client->addr == addr) {
681 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
682 "delete_device", client->name, client->addr);
684 list_del(&client->detected);
685 i2c_unregister_device(client);
690 i2c_unlock_adapter(adap);
693 dev_err(dev, "%s: Can't find device in list\n",
698 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
699 static DEVICE_ATTR(delete_device, S_IWUSR, NULL, i2c_sysfs_delete_device);
701 static struct attribute *i2c_adapter_attrs[] = {
703 &dev_attr_new_device.attr,
704 &dev_attr_delete_device.attr,
708 static struct attribute_group i2c_adapter_attr_group = {
709 .attrs = i2c_adapter_attrs,
712 static const struct attribute_group *i2c_adapter_attr_groups[] = {
713 &i2c_adapter_attr_group,
717 static struct device_type i2c_adapter_type = {
718 .groups = i2c_adapter_attr_groups,
719 .release = i2c_adapter_dev_release,
722 #ifdef CONFIG_I2C_COMPAT
723 static struct class_compat *i2c_adapter_compat_class;
726 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
728 struct i2c_devinfo *devinfo;
730 down_read(&__i2c_board_lock);
731 list_for_each_entry(devinfo, &__i2c_board_list, list) {
732 if (devinfo->busnum == adapter->nr
733 && !i2c_new_device(adapter,
734 &devinfo->board_info))
735 dev_err(&adapter->dev,
736 "Can't create device at 0x%02x\n",
737 devinfo->board_info.addr);
739 up_read(&__i2c_board_lock);
742 static int i2c_do_add_adapter(struct i2c_driver *driver,
743 struct i2c_adapter *adap)
745 /* Detect supported devices on that bus, and instantiate them */
746 i2c_detect(adap, driver);
748 /* Let legacy drivers scan this bus for matching devices */
749 if (driver->attach_adapter) {
750 /* We ignore the return code; if it fails, too bad */
751 driver->attach_adapter(adap);
756 static int __process_new_adapter(struct device_driver *d, void *data)
758 return i2c_do_add_adapter(to_i2c_driver(d), data);
761 static int i2c_register_adapter(struct i2c_adapter *adap)
765 /* Can't register until after driver model init */
766 if (unlikely(WARN_ON(!i2c_bus_type.p))) {
771 rt_mutex_init(&adap->bus_lock);
772 INIT_LIST_HEAD(&adap->userspace_clients);
774 /* Set default timeout to 1 second if not already set */
775 if (adap->timeout == 0)
778 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
779 adap->dev.bus = &i2c_bus_type;
780 adap->dev.type = &i2c_adapter_type;
781 res = device_register(&adap->dev);
785 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
787 #ifdef CONFIG_I2C_COMPAT
788 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
792 "Failed to create compatibility class link\n");
795 /* create pre-declared device nodes */
796 if (adap->nr < __i2c_first_dynamic_bus_num)
797 i2c_scan_static_board_info(adap);
799 /* Register devices from the device tree */
800 of_i2c_register_devices(adap);
803 mutex_lock(&core_lock);
804 dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,
805 __process_new_adapter);
806 mutex_unlock(&core_lock);
811 mutex_lock(&core_lock);
812 idr_remove(&i2c_adapter_idr, adap->nr);
813 mutex_unlock(&core_lock);
818 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
819 * @adapter: the adapter to add
822 * This routine is used to declare an I2C adapter when its bus number
823 * doesn't matter. Examples: for I2C adapters dynamically added by
824 * USB links or PCI plugin cards.
826 * When this returns zero, a new bus number was allocated and stored
827 * in adap->nr, and the specified adapter became available for clients.
828 * Otherwise, a negative errno value is returned.
830 int i2c_add_adapter(struct i2c_adapter *adapter)
835 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
838 mutex_lock(&core_lock);
839 /* "above" here means "above or equal to", sigh */
840 res = idr_get_new_above(&i2c_adapter_idr, adapter,
841 __i2c_first_dynamic_bus_num, &id);
842 mutex_unlock(&core_lock);
851 return i2c_register_adapter(adapter);
853 EXPORT_SYMBOL(i2c_add_adapter);
856 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
857 * @adap: the adapter to register (with adap->nr initialized)
860 * This routine is used to declare an I2C adapter when its bus number
861 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
862 * or otherwise built in to the system's mainboard, and where i2c_board_info
863 * is used to properly configure I2C devices.
865 * If no devices have pre-been declared for this bus, then be sure to
866 * register the adapter before any dynamically allocated ones. Otherwise
867 * the required bus ID may not be available.
869 * When this returns zero, the specified adapter became available for
870 * clients using the bus number provided in adap->nr. Also, the table
871 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
872 * and the appropriate driver model device nodes are created. Otherwise, a
873 * negative errno value is returned.
875 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
880 if (adap->nr & ~MAX_ID_MASK)
884 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
887 mutex_lock(&core_lock);
888 /* "above" here means "above or equal to", sigh;
889 * we need the "equal to" result to force the result
891 status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id);
892 if (status == 0 && id != adap->nr) {
894 idr_remove(&i2c_adapter_idr, id);
896 mutex_unlock(&core_lock);
897 if (status == -EAGAIN)
901 status = i2c_register_adapter(adap);
904 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
906 static int i2c_do_del_adapter(struct i2c_driver *driver,
907 struct i2c_adapter *adapter)
909 struct i2c_client *client, *_n;
912 /* Remove the devices we created ourselves as the result of hardware
913 * probing (using a driver's detect method) */
914 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
915 if (client->adapter == adapter) {
916 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
917 client->name, client->addr);
918 list_del(&client->detected);
919 i2c_unregister_device(client);
923 if (!driver->detach_adapter)
925 res = driver->detach_adapter(adapter);
927 dev_err(&adapter->dev, "detach_adapter failed (%d) "
928 "for driver [%s]\n", res, driver->driver.name);
932 static int __unregister_client(struct device *dev, void *dummy)
934 struct i2c_client *client = i2c_verify_client(dev);
936 i2c_unregister_device(client);
940 static int __process_removed_adapter(struct device_driver *d, void *data)
942 return i2c_do_del_adapter(to_i2c_driver(d), data);
946 * i2c_del_adapter - unregister I2C adapter
947 * @adap: the adapter being unregistered
950 * This unregisters an I2C adapter which was previously registered
951 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
953 int i2c_del_adapter(struct i2c_adapter *adap)
956 struct i2c_adapter *found;
957 struct i2c_client *client, *next;
959 /* First make sure that this adapter was ever added */
960 mutex_lock(&core_lock);
961 found = idr_find(&i2c_adapter_idr, adap->nr);
962 mutex_unlock(&core_lock);
964 pr_debug("i2c-core: attempting to delete unregistered "
965 "adapter [%s]\n", adap->name);
969 /* Tell drivers about this removal */
970 mutex_lock(&core_lock);
971 res = bus_for_each_drv(&i2c_bus_type, NULL, adap,
972 __process_removed_adapter);
973 mutex_unlock(&core_lock);
977 /* Remove devices instantiated from sysfs */
978 i2c_lock_adapter(adap);
979 list_for_each_entry_safe(client, next, &adap->userspace_clients,
981 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
983 list_del(&client->detected);
984 i2c_unregister_device(client);
986 i2c_unlock_adapter(adap);
988 /* Detach any active clients. This can't fail, thus we do not
989 checking the returned value. */
990 res = device_for_each_child(&adap->dev, NULL, __unregister_client);
992 #ifdef CONFIG_I2C_COMPAT
993 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
997 /* device name is gone after device_unregister */
998 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1000 /* clean up the sysfs representation */
1001 init_completion(&adap->dev_released);
1002 device_unregister(&adap->dev);
1004 /* wait for sysfs to drop all references */
1005 wait_for_completion(&adap->dev_released);
1008 mutex_lock(&core_lock);
1009 idr_remove(&i2c_adapter_idr, adap->nr);
1010 mutex_unlock(&core_lock);
1012 /* Clear the device structure in case this adapter is ever going to be
1014 memset(&adap->dev, 0, sizeof(adap->dev));
1018 EXPORT_SYMBOL(i2c_del_adapter);
1021 /* ------------------------------------------------------------------------- */
1023 static int __process_new_driver(struct device *dev, void *data)
1025 if (dev->type != &i2c_adapter_type)
1027 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1031 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1032 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1035 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1039 /* Can't register until after driver model init */
1040 if (unlikely(WARN_ON(!i2c_bus_type.p)))
1043 /* add the driver to the list of i2c drivers in the driver core */
1044 driver->driver.owner = owner;
1045 driver->driver.bus = &i2c_bus_type;
1047 /* When registration returns, the driver core
1048 * will have called probe() for all matching-but-unbound devices.
1050 res = driver_register(&driver->driver);
1054 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1056 INIT_LIST_HEAD(&driver->clients);
1057 /* Walk the adapters that are already present */
1058 mutex_lock(&core_lock);
1059 bus_for_each_dev(&i2c_bus_type, NULL, driver, __process_new_driver);
1060 mutex_unlock(&core_lock);
1064 EXPORT_SYMBOL(i2c_register_driver);
1066 static int __process_removed_driver(struct device *dev, void *data)
1068 if (dev->type != &i2c_adapter_type)
1070 return i2c_do_del_adapter(data, to_i2c_adapter(dev));
1074 * i2c_del_driver - unregister I2C driver
1075 * @driver: the driver being unregistered
1076 * Context: can sleep
1078 void i2c_del_driver(struct i2c_driver *driver)
1080 mutex_lock(&core_lock);
1081 bus_for_each_dev(&i2c_bus_type, NULL, driver, __process_removed_driver);
1082 mutex_unlock(&core_lock);
1084 driver_unregister(&driver->driver);
1085 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1087 EXPORT_SYMBOL(i2c_del_driver);
1089 /* ------------------------------------------------------------------------- */
1092 * i2c_use_client - increments the reference count of the i2c client structure
1093 * @client: the client being referenced
1095 * Each live reference to a client should be refcounted. The driver model does
1096 * that automatically as part of driver binding, so that most drivers don't
1097 * need to do this explicitly: they hold a reference until they're unbound
1100 * A pointer to the client with the incremented reference counter is returned.
1102 struct i2c_client *i2c_use_client(struct i2c_client *client)
1104 if (client && get_device(&client->dev))
1108 EXPORT_SYMBOL(i2c_use_client);
1111 * i2c_release_client - release a use of the i2c client structure
1112 * @client: the client being no longer referenced
1114 * Must be called when a user of a client is finished with it.
1116 void i2c_release_client(struct i2c_client *client)
1119 put_device(&client->dev);
1121 EXPORT_SYMBOL(i2c_release_client);
1123 struct i2c_cmd_arg {
1128 static int i2c_cmd(struct device *dev, void *_arg)
1130 struct i2c_client *client = i2c_verify_client(dev);
1131 struct i2c_cmd_arg *arg = _arg;
1133 if (client && client->driver && client->driver->command)
1134 client->driver->command(client, arg->cmd, arg->arg);
1138 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1140 struct i2c_cmd_arg cmd_arg;
1144 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1146 EXPORT_SYMBOL(i2c_clients_command);
1148 static int __init i2c_init(void)
1152 retval = bus_register(&i2c_bus_type);
1155 #ifdef CONFIG_I2C_COMPAT
1156 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1157 if (!i2c_adapter_compat_class) {
1162 retval = i2c_add_driver(&dummy_driver);
1168 #ifdef CONFIG_I2C_COMPAT
1169 class_compat_unregister(i2c_adapter_compat_class);
1172 bus_unregister(&i2c_bus_type);
1176 static void __exit i2c_exit(void)
1178 i2c_del_driver(&dummy_driver);
1179 #ifdef CONFIG_I2C_COMPAT
1180 class_compat_unregister(i2c_adapter_compat_class);
1182 bus_unregister(&i2c_bus_type);
1185 /* We must initialize early, because some subsystems register i2c drivers
1186 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1188 postcore_initcall(i2c_init);
1189 module_exit(i2c_exit);
1191 /* ----------------------------------------------------
1192 * the functional interface to the i2c busses.
1193 * ----------------------------------------------------
1197 * i2c_transfer - execute a single or combined I2C message
1198 * @adap: Handle to I2C bus
1199 * @msgs: One or more messages to execute before STOP is issued to
1200 * terminate the operation; each message begins with a START.
1201 * @num: Number of messages to be executed.
1203 * Returns negative errno, else the number of messages executed.
1205 * Note that there is no requirement that each message be sent to
1206 * the same slave address, although that is the most common model.
1208 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1210 unsigned long orig_jiffies;
1213 /* REVISIT the fault reporting model here is weak:
1215 * - When we get an error after receiving N bytes from a slave,
1216 * there is no way to report "N".
1218 * - When we get a NAK after transmitting N bytes to a slave,
1219 * there is no way to report "N" ... or to let the master
1220 * continue executing the rest of this combined message, if
1221 * that's the appropriate response.
1223 * - When for example "num" is two and we successfully complete
1224 * the first message but get an error part way through the
1225 * second, it's unclear whether that should be reported as
1226 * one (discarding status on the second message) or errno
1227 * (discarding status on the first one).
1230 if (adap->algo->master_xfer) {
1232 for (ret = 0; ret < num; ret++) {
1233 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
1234 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
1235 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
1236 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1240 if (in_atomic() || irqs_disabled()) {
1241 ret = rt_mutex_trylock(&adap->bus_lock);
1243 /* I2C activity is ongoing. */
1246 rt_mutex_lock(&adap->bus_lock);
1249 /* Retry automatically on arbitration loss */
1250 orig_jiffies = jiffies;
1251 for (ret = 0, try = 0; try <= adap->retries; try++) {
1252 ret = adap->algo->master_xfer(adap, msgs, num);
1255 if (time_after(jiffies, orig_jiffies + adap->timeout))
1258 rt_mutex_unlock(&adap->bus_lock);
1262 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1266 EXPORT_SYMBOL(i2c_transfer);
1269 * i2c_master_send - issue a single I2C message in master transmit mode
1270 * @client: Handle to slave device
1271 * @buf: Data that will be written to the slave
1272 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1274 * Returns negative errno, or else the number of bytes written.
1276 int i2c_master_send(struct i2c_client *client, const char *buf, int count)
1279 struct i2c_adapter *adap = client->adapter;
1282 msg.addr = client->addr;
1283 msg.flags = client->flags & I2C_M_TEN;
1285 msg.buf = (char *)buf;
1287 ret = i2c_transfer(adap, &msg, 1);
1289 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1290 transmitted, else error code. */
1291 return (ret == 1) ? count : ret;
1293 EXPORT_SYMBOL(i2c_master_send);
1296 * i2c_master_recv - issue a single I2C message in master receive mode
1297 * @client: Handle to slave device
1298 * @buf: Where to store data read from slave
1299 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1301 * Returns negative errno, or else the number of bytes read.
1303 int i2c_master_recv(struct i2c_client *client, char *buf, int count)
1305 struct i2c_adapter *adap = client->adapter;
1309 msg.addr = client->addr;
1310 msg.flags = client->flags & I2C_M_TEN;
1311 msg.flags |= I2C_M_RD;
1315 ret = i2c_transfer(adap, &msg, 1);
1317 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1318 transmitted, else error code. */
1319 return (ret == 1) ? count : ret;
1321 EXPORT_SYMBOL(i2c_master_recv);
1323 /* ----------------------------------------------------
1324 * the i2c address scanning function
1325 * Will not work for 10-bit addresses!
1326 * ----------------------------------------------------
1330 * Legacy default probe function, mostly relevant for SMBus. The default
1331 * probe method is a quick write, but it is known to corrupt the 24RF08
1332 * EEPROMs due to a state machine bug, and could also irreversibly
1333 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1334 * we use a short byte read instead. Also, some bus drivers don't implement
1335 * quick write, so we fallback to a byte read in that case too.
1336 * On x86, there is another special case for FSC hardware monitoring chips,
1337 * which want regular byte reads (address 0x73.) Fortunately, these are the
1338 * only known chips using this I2C address on PC hardware.
1339 * Returns 1 if probe succeeded, 0 if not.
1341 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1344 union i2c_smbus_data dummy;
1347 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1348 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1349 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1350 I2C_SMBUS_BYTE_DATA, &dummy);
1353 if ((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50
1354 || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
1355 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1356 I2C_SMBUS_BYTE, &dummy);
1358 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
1359 I2C_SMBUS_QUICK, NULL);
1364 static int i2c_detect_address(struct i2c_client *temp_client,
1365 struct i2c_driver *driver)
1367 struct i2c_board_info info;
1368 struct i2c_adapter *adapter = temp_client->adapter;
1369 int addr = temp_client->addr;
1372 /* Make sure the address is valid */
1373 err = i2c_check_addr_validity(addr);
1375 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
1380 /* Skip if already in use */
1381 if (i2c_check_addr_busy(adapter, addr))
1384 /* Make sure there is something at this address */
1385 if (!i2c_default_probe(adapter, addr))
1388 /* Finally call the custom detection function */
1389 memset(&info, 0, sizeof(struct i2c_board_info));
1391 err = driver->detect(temp_client, &info);
1393 /* -ENODEV is returned if the detection fails. We catch it
1394 here as this isn't an error. */
1395 return err == -ENODEV ? 0 : err;
1398 /* Consistency check */
1399 if (info.type[0] == '\0') {
1400 dev_err(&adapter->dev, "%s detection function provided "
1401 "no name for 0x%x\n", driver->driver.name,
1404 struct i2c_client *client;
1406 /* Detection succeeded, instantiate the device */
1407 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
1408 info.type, info.addr);
1409 client = i2c_new_device(adapter, &info);
1411 list_add_tail(&client->detected, &driver->clients);
1413 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
1414 info.type, info.addr);
1419 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
1421 const unsigned short *address_list;
1422 struct i2c_client *temp_client;
1424 int adap_id = i2c_adapter_id(adapter);
1426 address_list = driver->address_list;
1427 if (!driver->detect || !address_list)
1430 /* Set up a temporary client to help detect callback */
1431 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
1434 temp_client->adapter = adapter;
1436 /* Stop here if the classes do not match */
1437 if (!(adapter->class & driver->class))
1440 /* Stop here if the bus doesn't support probing */
1441 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE)) {
1442 if (address_list[0] == I2C_CLIENT_END)
1445 dev_warn(&adapter->dev, "Probing not supported\n");
1450 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
1451 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
1452 "addr 0x%02x\n", adap_id, address_list[i]);
1453 temp_client->addr = address_list[i];
1454 err = i2c_detect_address(temp_client, driver);
1465 i2c_new_probed_device(struct i2c_adapter *adap,
1466 struct i2c_board_info *info,
1467 unsigned short const *addr_list,
1468 int (*probe)(struct i2c_adapter *, unsigned short addr))
1473 /* Stop here if the bus doesn't support probing */
1474 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) {
1475 dev_err(&adap->dev, "Probing not supported\n");
1478 probe = i2c_default_probe;
1481 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
1482 /* Check address validity */
1483 if (i2c_check_addr_validity(addr_list[i]) < 0) {
1484 dev_warn(&adap->dev, "Invalid 7-bit address "
1485 "0x%02x\n", addr_list[i]);
1489 /* Check address availability */
1490 if (i2c_check_addr_busy(adap, addr_list[i])) {
1491 dev_dbg(&adap->dev, "Address 0x%02x already in "
1492 "use, not probing\n", addr_list[i]);
1496 /* Test address responsiveness */
1497 if (probe(adap, addr_list[i]))
1501 if (addr_list[i] == I2C_CLIENT_END) {
1502 dev_dbg(&adap->dev, "Probing failed, no device found\n");
1506 info->addr = addr_list[i];
1507 return i2c_new_device(adap, info);
1509 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
1511 struct i2c_adapter *i2c_get_adapter(int id)
1513 struct i2c_adapter *adapter;
1515 mutex_lock(&core_lock);
1516 adapter = idr_find(&i2c_adapter_idr, id);
1517 if (adapter && !try_module_get(adapter->owner))
1520 mutex_unlock(&core_lock);
1523 EXPORT_SYMBOL(i2c_get_adapter);
1525 void i2c_put_adapter(struct i2c_adapter *adap)
1527 module_put(adap->owner);
1529 EXPORT_SYMBOL(i2c_put_adapter);
1531 /* The SMBus parts */
1533 #define POLY (0x1070U << 3)
1534 static u8 crc8(u16 data)
1538 for (i = 0; i < 8; i++) {
1543 return (u8)(data >> 8);
1546 /* Incremental CRC8 over count bytes in the array pointed to by p */
1547 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
1551 for (i = 0; i < count; i++)
1552 crc = crc8((crc ^ p[i]) << 8);
1556 /* Assume a 7-bit address, which is reasonable for SMBus */
1557 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
1559 /* The address will be sent first */
1560 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
1561 pec = i2c_smbus_pec(pec, &addr, 1);
1563 /* The data buffer follows */
1564 return i2c_smbus_pec(pec, msg->buf, msg->len);
1567 /* Used for write only transactions */
1568 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
1570 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
1574 /* Return <0 on CRC error
1575 If there was a write before this read (most cases) we need to take the
1576 partial CRC from the write part into account.
1577 Note that this function does modify the message (we need to decrease the
1578 message length to hide the CRC byte from the caller). */
1579 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
1581 u8 rpec = msg->buf[--msg->len];
1582 cpec = i2c_smbus_msg_pec(cpec, msg);
1585 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1593 * i2c_smbus_read_byte - SMBus "receive byte" protocol
1594 * @client: Handle to slave device
1596 * This executes the SMBus "receive byte" protocol, returning negative errno
1597 * else the byte received from the device.
1599 s32 i2c_smbus_read_byte(struct i2c_client *client)
1601 union i2c_smbus_data data;
1604 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1606 I2C_SMBUS_BYTE, &data);
1607 return (status < 0) ? status : data.byte;
1609 EXPORT_SYMBOL(i2c_smbus_read_byte);
1612 * i2c_smbus_write_byte - SMBus "send byte" protocol
1613 * @client: Handle to slave device
1614 * @value: Byte to be sent
1616 * This executes the SMBus "send byte" protocol, returning negative errno
1617 * else zero on success.
1619 s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
1621 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1622 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
1624 EXPORT_SYMBOL(i2c_smbus_write_byte);
1627 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
1628 * @client: Handle to slave device
1629 * @command: Byte interpreted by slave
1631 * This executes the SMBus "read byte" protocol, returning negative errno
1632 * else a data byte received from the device.
1634 s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
1636 union i2c_smbus_data data;
1639 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1640 I2C_SMBUS_READ, command,
1641 I2C_SMBUS_BYTE_DATA, &data);
1642 return (status < 0) ? status : data.byte;
1644 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
1647 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
1648 * @client: Handle to slave device
1649 * @command: Byte interpreted by slave
1650 * @value: Byte being written
1652 * This executes the SMBus "write byte" protocol, returning negative errno
1653 * else zero on success.
1655 s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
1657 union i2c_smbus_data data;
1659 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1660 I2C_SMBUS_WRITE, command,
1661 I2C_SMBUS_BYTE_DATA, &data);
1663 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
1666 * i2c_smbus_read_word_data - SMBus "read word" protocol
1667 * @client: Handle to slave device
1668 * @command: Byte interpreted by slave
1670 * This executes the SMBus "read word" protocol, returning negative errno
1671 * else a 16-bit unsigned "word" received from the device.
1673 s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
1675 union i2c_smbus_data data;
1678 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1679 I2C_SMBUS_READ, command,
1680 I2C_SMBUS_WORD_DATA, &data);
1681 return (status < 0) ? status : data.word;
1683 EXPORT_SYMBOL(i2c_smbus_read_word_data);
1686 * i2c_smbus_write_word_data - SMBus "write word" protocol
1687 * @client: Handle to slave device
1688 * @command: Byte interpreted by slave
1689 * @value: 16-bit "word" being written
1691 * This executes the SMBus "write word" protocol, returning negative errno
1692 * else zero on success.
1694 s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
1696 union i2c_smbus_data data;
1698 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1699 I2C_SMBUS_WRITE, command,
1700 I2C_SMBUS_WORD_DATA, &data);
1702 EXPORT_SYMBOL(i2c_smbus_write_word_data);
1705 * i2c_smbus_process_call - SMBus "process call" protocol
1706 * @client: Handle to slave device
1707 * @command: Byte interpreted by slave
1708 * @value: 16-bit "word" being written
1710 * This executes the SMBus "process call" protocol, returning negative errno
1711 * else a 16-bit unsigned "word" received from the device.
1713 s32 i2c_smbus_process_call(struct i2c_client *client, u8 command, u16 value)
1715 union i2c_smbus_data data;
1719 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1720 I2C_SMBUS_WRITE, command,
1721 I2C_SMBUS_PROC_CALL, &data);
1722 return (status < 0) ? status : data.word;
1724 EXPORT_SYMBOL(i2c_smbus_process_call);
1727 * i2c_smbus_read_block_data - SMBus "block read" protocol
1728 * @client: Handle to slave device
1729 * @command: Byte interpreted by slave
1730 * @values: Byte array into which data will be read; big enough to hold
1731 * the data returned by the slave. SMBus allows at most 32 bytes.
1733 * This executes the SMBus "block read" protocol, returning negative errno
1734 * else the number of data bytes in the slave's response.
1736 * Note that using this function requires that the client's adapter support
1737 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1738 * support this; its emulation through I2C messaging relies on a specific
1739 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1741 s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
1744 union i2c_smbus_data data;
1747 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1748 I2C_SMBUS_READ, command,
1749 I2C_SMBUS_BLOCK_DATA, &data);
1753 memcpy(values, &data.block[1], data.block[0]);
1754 return data.block[0];
1756 EXPORT_SYMBOL(i2c_smbus_read_block_data);
1759 * i2c_smbus_write_block_data - SMBus "block write" protocol
1760 * @client: Handle to slave device
1761 * @command: Byte interpreted by slave
1762 * @length: Size of data block; SMBus allows at most 32 bytes
1763 * @values: Byte array which will be written.
1765 * This executes the SMBus "block write" protocol, returning negative errno
1766 * else zero on success.
1768 s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
1769 u8 length, const u8 *values)
1771 union i2c_smbus_data data;
1773 if (length > I2C_SMBUS_BLOCK_MAX)
1774 length = I2C_SMBUS_BLOCK_MAX;
1775 data.block[0] = length;
1776 memcpy(&data.block[1], values, length);
1777 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1778 I2C_SMBUS_WRITE, command,
1779 I2C_SMBUS_BLOCK_DATA, &data);
1781 EXPORT_SYMBOL(i2c_smbus_write_block_data);
1783 /* Returns the number of read bytes */
1784 s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
1785 u8 length, u8 *values)
1787 union i2c_smbus_data data;
1790 if (length > I2C_SMBUS_BLOCK_MAX)
1791 length = I2C_SMBUS_BLOCK_MAX;
1792 data.block[0] = length;
1793 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1794 I2C_SMBUS_READ, command,
1795 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1799 memcpy(values, &data.block[1], data.block[0]);
1800 return data.block[0];
1802 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
1804 s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client, u8 command,
1805 u8 length, const u8 *values)
1807 union i2c_smbus_data data;
1809 if (length > I2C_SMBUS_BLOCK_MAX)
1810 length = I2C_SMBUS_BLOCK_MAX;
1811 data.block[0] = length;
1812 memcpy(data.block + 1, values, length);
1813 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1814 I2C_SMBUS_WRITE, command,
1815 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1817 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
1819 /* Simulate a SMBus command using the i2c protocol
1820 No checking of parameters is done! */
1821 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
1822 unsigned short flags,
1823 char read_write, u8 command, int size,
1824 union i2c_smbus_data *data)
1826 /* So we need to generate a series of msgs. In the case of writing, we
1827 need to use only one message; when reading, we need two. We initialize
1828 most things with sane defaults, to keep the code below somewhat
1830 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
1831 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
1832 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
1833 struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
1834 { addr, flags | I2C_M_RD, 0, msgbuf1 }
1840 msgbuf0[0] = command;
1842 case I2C_SMBUS_QUICK:
1844 /* Special case: The read/write field is used as data */
1845 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
1849 case I2C_SMBUS_BYTE:
1850 if (read_write == I2C_SMBUS_READ) {
1851 /* Special case: only a read! */
1852 msg[0].flags = I2C_M_RD | flags;
1856 case I2C_SMBUS_BYTE_DATA:
1857 if (read_write == I2C_SMBUS_READ)
1861 msgbuf0[1] = data->byte;
1864 case I2C_SMBUS_WORD_DATA:
1865 if (read_write == I2C_SMBUS_READ)
1869 msgbuf0[1] = data->word & 0xff;
1870 msgbuf0[2] = data->word >> 8;
1873 case I2C_SMBUS_PROC_CALL:
1874 num = 2; /* Special case */
1875 read_write = I2C_SMBUS_READ;
1878 msgbuf0[1] = data->word & 0xff;
1879 msgbuf0[2] = data->word >> 8;
1881 case I2C_SMBUS_BLOCK_DATA:
1882 if (read_write == I2C_SMBUS_READ) {
1883 msg[1].flags |= I2C_M_RECV_LEN;
1884 msg[1].len = 1; /* block length will be added by
1885 the underlying bus driver */
1887 msg[0].len = data->block[0] + 2;
1888 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
1889 dev_err(&adapter->dev,
1890 "Invalid block write size %d\n",
1894 for (i = 1; i < msg[0].len; i++)
1895 msgbuf0[i] = data->block[i-1];
1898 case I2C_SMBUS_BLOCK_PROC_CALL:
1899 num = 2; /* Another special case */
1900 read_write = I2C_SMBUS_READ;
1901 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
1902 dev_err(&adapter->dev,
1903 "Invalid block write size %d\n",
1907 msg[0].len = data->block[0] + 2;
1908 for (i = 1; i < msg[0].len; i++)
1909 msgbuf0[i] = data->block[i-1];
1910 msg[1].flags |= I2C_M_RECV_LEN;
1911 msg[1].len = 1; /* block length will be added by
1912 the underlying bus driver */
1914 case I2C_SMBUS_I2C_BLOCK_DATA:
1915 if (read_write == I2C_SMBUS_READ) {
1916 msg[1].len = data->block[0];
1918 msg[0].len = data->block[0] + 1;
1919 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
1920 dev_err(&adapter->dev,
1921 "Invalid block write size %d\n",
1925 for (i = 1; i <= data->block[0]; i++)
1926 msgbuf0[i] = data->block[i];
1930 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
1934 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
1935 && size != I2C_SMBUS_I2C_BLOCK_DATA);
1937 /* Compute PEC if first message is a write */
1938 if (!(msg[0].flags & I2C_M_RD)) {
1939 if (num == 1) /* Write only */
1940 i2c_smbus_add_pec(&msg[0]);
1941 else /* Write followed by read */
1942 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
1944 /* Ask for PEC if last message is a read */
1945 if (msg[num-1].flags & I2C_M_RD)
1949 status = i2c_transfer(adapter, msg, num);
1953 /* Check PEC if last message is a read */
1954 if (i && (msg[num-1].flags & I2C_M_RD)) {
1955 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
1960 if (read_write == I2C_SMBUS_READ)
1962 case I2C_SMBUS_BYTE:
1963 data->byte = msgbuf0[0];
1965 case I2C_SMBUS_BYTE_DATA:
1966 data->byte = msgbuf1[0];
1968 case I2C_SMBUS_WORD_DATA:
1969 case I2C_SMBUS_PROC_CALL:
1970 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
1972 case I2C_SMBUS_I2C_BLOCK_DATA:
1973 for (i = 0; i < data->block[0]; i++)
1974 data->block[i+1] = msgbuf1[i];
1976 case I2C_SMBUS_BLOCK_DATA:
1977 case I2C_SMBUS_BLOCK_PROC_CALL:
1978 for (i = 0; i < msgbuf1[0] + 1; i++)
1979 data->block[i] = msgbuf1[i];
1986 * i2c_smbus_xfer - execute SMBus protocol operations
1987 * @adapter: Handle to I2C bus
1988 * @addr: Address of SMBus slave on that bus
1989 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
1990 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
1991 * @command: Byte interpreted by slave, for protocols which use such bytes
1992 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
1993 * @data: Data to be read or written
1995 * This executes an SMBus protocol operation, and returns a negative
1996 * errno code else zero on success.
1998 s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
1999 char read_write, u8 command, int protocol,
2000 union i2c_smbus_data *data)
2002 unsigned long orig_jiffies;
2006 flags &= I2C_M_TEN | I2C_CLIENT_PEC;
2008 if (adapter->algo->smbus_xfer) {
2009 rt_mutex_lock(&adapter->bus_lock);
2011 /* Retry automatically on arbitration loss */
2012 orig_jiffies = jiffies;
2013 for (res = 0, try = 0; try <= adapter->retries; try++) {
2014 res = adapter->algo->smbus_xfer(adapter, addr, flags,
2015 read_write, command,
2019 if (time_after(jiffies,
2020 orig_jiffies + adapter->timeout))
2023 rt_mutex_unlock(&adapter->bus_lock);
2025 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
2026 command, protocol, data);
2030 EXPORT_SYMBOL(i2c_smbus_xfer);
2032 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2033 MODULE_DESCRIPTION("I2C-Bus main module");
2034 MODULE_LICENSE("GPL");