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/platform_device.h>
33 #include <linux/mutex.h>
34 #include <linux/completion.h>
35 #include <linux/hardirq.h>
36 #include <linux/irqflags.h>
37 #include <asm/uaccess.h>
42 static DEFINE_MUTEX(core_lock);
43 static DEFINE_IDR(i2c_adapter_idr);
45 #define is_newstyle_driver(d) ((d)->probe || (d)->remove)
47 /* ------------------------------------------------------------------------- */
49 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
50 const struct i2c_client *client)
53 if (strcmp(client->name, id->name) == 0)
60 static int i2c_device_match(struct device *dev, struct device_driver *drv)
62 struct i2c_client *client = to_i2c_client(dev);
63 struct i2c_driver *driver = to_i2c_driver(drv);
65 /* make legacy i2c drivers bypass driver model probing entirely;
66 * such drivers scan each i2c adapter/bus themselves.
68 if (!is_newstyle_driver(driver))
71 /* match on an id table if there is one */
73 return i2c_match_id(driver->id_table, client) != NULL;
80 /* uevent helps with hotplug: modprobe -q $(MODALIAS) */
81 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
83 struct i2c_client *client = to_i2c_client(dev);
85 /* by definition, legacy drivers can't hotplug */
89 if (add_uevent_var(env, "MODALIAS=%s%s",
90 I2C_MODULE_PREFIX, client->name))
92 dev_dbg(dev, "uevent\n");
97 #define i2c_device_uevent NULL
98 #endif /* CONFIG_HOTPLUG */
100 static int i2c_device_probe(struct device *dev)
102 struct i2c_client *client = to_i2c_client(dev);
103 struct i2c_driver *driver = to_i2c_driver(dev->driver);
104 const struct i2c_device_id *id;
109 client->driver = driver;
110 dev_dbg(dev, "probe\n");
112 if (driver->id_table)
113 id = i2c_match_id(driver->id_table, client);
116 status = driver->probe(client, id);
118 client->driver = NULL;
122 static int i2c_device_remove(struct device *dev)
124 struct i2c_client *client = to_i2c_client(dev);
125 struct i2c_driver *driver;
131 driver = to_i2c_driver(dev->driver);
132 if (driver->remove) {
133 dev_dbg(dev, "remove\n");
134 status = driver->remove(client);
140 client->driver = NULL;
144 static void i2c_device_shutdown(struct device *dev)
146 struct i2c_driver *driver;
150 driver = to_i2c_driver(dev->driver);
151 if (driver->shutdown)
152 driver->shutdown(to_i2c_client(dev));
155 static int i2c_device_suspend(struct device * dev, pm_message_t mesg)
157 struct i2c_driver *driver;
161 driver = to_i2c_driver(dev->driver);
162 if (!driver->suspend)
164 return driver->suspend(to_i2c_client(dev), mesg);
167 static int i2c_device_resume(struct device * dev)
169 struct i2c_driver *driver;
173 driver = to_i2c_driver(dev->driver);
176 return driver->resume(to_i2c_client(dev));
179 static void i2c_client_release(struct device *dev)
181 struct i2c_client *client = to_i2c_client(dev);
182 complete(&client->released);
185 static void i2c_client_dev_release(struct device *dev)
187 kfree(to_i2c_client(dev));
190 static ssize_t show_client_name(struct device *dev, struct device_attribute *attr, char *buf)
192 struct i2c_client *client = to_i2c_client(dev);
193 return sprintf(buf, "%s\n", client->name);
196 static ssize_t show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
198 struct i2c_client *client = to_i2c_client(dev);
199 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
202 static struct device_attribute i2c_dev_attrs[] = {
203 __ATTR(name, S_IRUGO, show_client_name, NULL),
204 /* modalias helps coldplug: modprobe $(cat .../modalias) */
205 __ATTR(modalias, S_IRUGO, show_modalias, NULL),
209 static struct bus_type i2c_bus_type = {
211 .dev_attrs = i2c_dev_attrs,
212 .match = i2c_device_match,
213 .uevent = i2c_device_uevent,
214 .probe = i2c_device_probe,
215 .remove = i2c_device_remove,
216 .shutdown = i2c_device_shutdown,
217 .suspend = i2c_device_suspend,
218 .resume = i2c_device_resume,
223 * i2c_verify_client - return parameter as i2c_client, or NULL
224 * @dev: device, probably from some driver model iterator
226 * When traversing the driver model tree, perhaps using driver model
227 * iterators like @device_for_each_child(), you can't assume very much
228 * about the nodes you find. Use this function to avoid oopses caused
229 * by wrongly treating some non-I2C device as an i2c_client.
231 struct i2c_client *i2c_verify_client(struct device *dev)
233 return (dev->bus == &i2c_bus_type)
237 EXPORT_SYMBOL(i2c_verify_client);
241 * i2c_new_device - instantiate an i2c device for use with a new style driver
242 * @adap: the adapter managing the device
243 * @info: describes one I2C device; bus_num is ignored
246 * Create a device to work with a new style i2c driver, where binding is
247 * handled through driver model probe()/remove() methods. This call is not
248 * appropriate for use by mainboad initialization logic, which usually runs
249 * during an arch_initcall() long before any i2c_adapter could exist.
251 * This returns the new i2c client, which may be saved for later use with
252 * i2c_unregister_device(); or NULL to indicate an error.
255 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
257 struct i2c_client *client;
260 client = kzalloc(sizeof *client, GFP_KERNEL);
264 client->adapter = adap;
266 client->dev.platform_data = info->platform_data;
267 device_init_wakeup(&client->dev, info->flags & I2C_CLIENT_WAKE);
269 client->flags = info->flags & ~I2C_CLIENT_WAKE;
270 client->addr = info->addr;
271 client->irq = info->irq;
273 strlcpy(client->name, info->type, sizeof(client->name));
275 /* a new style driver may be bound to this device when we
276 * return from this function, or any later moment (e.g. maybe
277 * hotplugging will load the driver module). and the device
278 * refcount model is the standard driver model one.
280 status = i2c_attach_client(client);
287 EXPORT_SYMBOL_GPL(i2c_new_device);
291 * i2c_unregister_device - reverse effect of i2c_new_device()
292 * @client: value returned from i2c_new_device()
295 void i2c_unregister_device(struct i2c_client *client)
297 struct i2c_adapter *adapter = client->adapter;
298 struct i2c_driver *driver = client->driver;
300 if (driver && !is_newstyle_driver(driver)) {
301 dev_err(&client->dev, "can't unregister devices "
302 "with legacy drivers\n");
307 mutex_lock(&adapter->clist_lock);
308 list_del(&client->list);
309 mutex_unlock(&adapter->clist_lock);
311 device_unregister(&client->dev);
313 EXPORT_SYMBOL_GPL(i2c_unregister_device);
316 static const struct i2c_device_id dummy_id[] = {
321 static int dummy_probe(struct i2c_client *client,
322 const struct i2c_device_id *id)
327 static int dummy_remove(struct i2c_client *client)
332 static struct i2c_driver dummy_driver = {
333 .driver.name = "dummy",
334 .probe = dummy_probe,
335 .remove = dummy_remove,
336 .id_table = dummy_id,
340 * i2c_new_dummy - return a new i2c device bound to a dummy driver
341 * @adapter: the adapter managing the device
342 * @address: seven bit address to be used
345 * This returns an I2C client bound to the "dummy" driver, intended for use
346 * with devices that consume multiple addresses. Examples of such chips
347 * include various EEPROMS (like 24c04 and 24c08 models).
349 * These dummy devices have two main uses. First, most I2C and SMBus calls
350 * except i2c_transfer() need a client handle; the dummy will be that handle.
351 * And second, this prevents the specified address from being bound to a
354 * This returns the new i2c client, which should be saved for later use with
355 * i2c_unregister_device(); or NULL to indicate an error.
358 i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
360 struct i2c_board_info info = {
361 I2C_BOARD_INFO("dummy", address),
364 return i2c_new_device(adapter, &info);
366 EXPORT_SYMBOL_GPL(i2c_new_dummy);
368 /* ------------------------------------------------------------------------- */
370 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
372 static void i2c_adapter_dev_release(struct device *dev)
374 struct i2c_adapter *adap = to_i2c_adapter(dev);
375 complete(&adap->dev_released);
379 show_adapter_name(struct device *dev, struct device_attribute *attr, char *buf)
381 struct i2c_adapter *adap = to_i2c_adapter(dev);
382 return sprintf(buf, "%s\n", adap->name);
385 static struct device_attribute i2c_adapter_attrs[] = {
386 __ATTR(name, S_IRUGO, show_adapter_name, NULL),
390 static struct class i2c_adapter_class = {
391 .owner = THIS_MODULE,
392 .name = "i2c-adapter",
393 .dev_attrs = i2c_adapter_attrs,
396 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
398 struct i2c_devinfo *devinfo;
400 mutex_lock(&__i2c_board_lock);
401 list_for_each_entry(devinfo, &__i2c_board_list, list) {
402 if (devinfo->busnum == adapter->nr
403 && !i2c_new_device(adapter,
404 &devinfo->board_info))
405 printk(KERN_ERR "i2c-core: can't create i2c%d-%04x\n",
406 i2c_adapter_id(adapter),
407 devinfo->board_info.addr);
409 mutex_unlock(&__i2c_board_lock);
412 static int i2c_do_add_adapter(struct device_driver *d, void *data)
414 struct i2c_driver *driver = to_i2c_driver(d);
415 struct i2c_adapter *adap = data;
417 if (driver->attach_adapter) {
418 /* We ignore the return code; if it fails, too bad */
419 driver->attach_adapter(adap);
424 static int i2c_register_adapter(struct i2c_adapter *adap)
428 mutex_init(&adap->bus_lock);
429 mutex_init(&adap->clist_lock);
430 INIT_LIST_HEAD(&adap->clients);
432 mutex_lock(&core_lock);
434 /* Add the adapter to the driver core.
435 * If the parent pointer is not set up,
436 * we add this adapter to the host bus.
438 if (adap->dev.parent == NULL) {
439 adap->dev.parent = &platform_bus;
440 pr_debug("I2C adapter driver [%s] forgot to specify "
441 "physical device\n", adap->name);
443 sprintf(adap->dev.bus_id, "i2c-%d", adap->nr);
444 adap->dev.release = &i2c_adapter_dev_release;
445 adap->dev.class = &i2c_adapter_class;
446 res = device_register(&adap->dev);
450 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
452 /* create pre-declared device nodes for new-style drivers */
453 if (adap->nr < __i2c_first_dynamic_bus_num)
454 i2c_scan_static_board_info(adap);
456 /* let legacy drivers scan this bus for matching devices */
457 dummy = bus_for_each_drv(&i2c_bus_type, NULL, adap,
461 mutex_unlock(&core_lock);
465 idr_remove(&i2c_adapter_idr, adap->nr);
470 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
471 * @adapter: the adapter to add
474 * This routine is used to declare an I2C adapter when its bus number
475 * doesn't matter. Examples: for I2C adapters dynamically added by
476 * USB links or PCI plugin cards.
478 * When this returns zero, a new bus number was allocated and stored
479 * in adap->nr, and the specified adapter became available for clients.
480 * Otherwise, a negative errno value is returned.
482 int i2c_add_adapter(struct i2c_adapter *adapter)
487 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
490 mutex_lock(&core_lock);
491 /* "above" here means "above or equal to", sigh */
492 res = idr_get_new_above(&i2c_adapter_idr, adapter,
493 __i2c_first_dynamic_bus_num, &id);
494 mutex_unlock(&core_lock);
503 return i2c_register_adapter(adapter);
505 EXPORT_SYMBOL(i2c_add_adapter);
508 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
509 * @adap: the adapter to register (with adap->nr initialized)
512 * This routine is used to declare an I2C adapter when its bus number
513 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
514 * or otherwise built in to the system's mainboard, and where i2c_board_info
515 * is used to properly configure I2C devices.
517 * If no devices have pre-been declared for this bus, then be sure to
518 * register the adapter before any dynamically allocated ones. Otherwise
519 * the required bus ID may not be available.
521 * When this returns zero, the specified adapter became available for
522 * clients using the bus number provided in adap->nr. Also, the table
523 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
524 * and the appropriate driver model device nodes are created. Otherwise, a
525 * negative errno value is returned.
527 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
532 if (adap->nr & ~MAX_ID_MASK)
536 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
539 mutex_lock(&core_lock);
540 /* "above" here means "above or equal to", sigh;
541 * we need the "equal to" result to force the result
543 status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id);
544 if (status == 0 && id != adap->nr) {
546 idr_remove(&i2c_adapter_idr, id);
548 mutex_unlock(&core_lock);
549 if (status == -EAGAIN)
553 status = i2c_register_adapter(adap);
556 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
558 static int i2c_do_del_adapter(struct device_driver *d, void *data)
560 struct i2c_driver *driver = to_i2c_driver(d);
561 struct i2c_adapter *adapter = data;
564 if (!driver->detach_adapter)
566 res = driver->detach_adapter(adapter);
568 dev_err(&adapter->dev, "detach_adapter failed (%d) "
569 "for driver [%s]\n", res, driver->driver.name);
574 * i2c_del_adapter - unregister I2C adapter
575 * @adap: the adapter being unregistered
578 * This unregisters an I2C adapter which was previously registered
579 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
581 int i2c_del_adapter(struct i2c_adapter *adap)
583 struct list_head *item, *_n;
584 struct i2c_client *client;
587 mutex_lock(&core_lock);
589 /* First make sure that this adapter was ever added */
590 if (idr_find(&i2c_adapter_idr, adap->nr) != adap) {
591 pr_debug("i2c-core: attempting to delete unregistered "
592 "adapter [%s]\n", adap->name);
597 /* Tell drivers about this removal */
598 res = bus_for_each_drv(&i2c_bus_type, NULL, adap,
603 /* detach any active clients. This must be done first, because
604 * it can fail; in which case we give up. */
605 list_for_each_safe(item, _n, &adap->clients) {
606 struct i2c_driver *driver;
608 client = list_entry(item, struct i2c_client, list);
609 driver = client->driver;
611 /* new style, follow standard driver model */
612 if (!driver || is_newstyle_driver(driver)) {
613 i2c_unregister_device(client);
617 /* legacy drivers create and remove clients themselves */
618 if ((res = driver->detach_client(client))) {
619 dev_err(&adap->dev, "detach_client failed for client "
620 "[%s] at address 0x%02x\n", client->name,
626 /* clean up the sysfs representation */
627 init_completion(&adap->dev_released);
628 device_unregister(&adap->dev);
630 /* wait for sysfs to drop all references */
631 wait_for_completion(&adap->dev_released);
634 idr_remove(&i2c_adapter_idr, adap->nr);
636 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
639 mutex_unlock(&core_lock);
642 EXPORT_SYMBOL(i2c_del_adapter);
645 /* ------------------------------------------------------------------------- */
647 static int __attach_adapter(struct device *dev, void *data)
649 struct i2c_adapter *adapter = to_i2c_adapter(dev);
650 struct i2c_driver *driver = data;
652 driver->attach_adapter(adapter);
658 * An i2c_driver is used with one or more i2c_client (device) nodes to access
659 * i2c slave chips, on a bus instance associated with some i2c_adapter. There
660 * are two models for binding the driver to its device: "new style" drivers
661 * follow the standard Linux driver model and just respond to probe() calls
662 * issued if the driver core sees they match(); "legacy" drivers create device
666 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
670 /* new style driver methods can't mix with legacy ones */
671 if (is_newstyle_driver(driver)) {
672 if (driver->attach_adapter || driver->detach_adapter
673 || driver->detach_client) {
675 "i2c-core: driver [%s] is confused\n",
676 driver->driver.name);
681 /* add the driver to the list of i2c drivers in the driver core */
682 driver->driver.owner = owner;
683 driver->driver.bus = &i2c_bus_type;
685 /* for new style drivers, when registration returns the driver core
686 * will have called probe() for all matching-but-unbound devices.
688 res = driver_register(&driver->driver);
692 mutex_lock(&core_lock);
694 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
696 /* legacy drivers scan i2c busses directly */
697 if (driver->attach_adapter)
698 class_for_each_device(&i2c_adapter_class, driver,
701 mutex_unlock(&core_lock);
704 EXPORT_SYMBOL(i2c_register_driver);
706 static int __detach_adapter(struct device *dev, void *data)
708 struct i2c_adapter *adapter = to_i2c_adapter(dev);
709 struct i2c_driver *driver = data;
711 /* Have a look at each adapter, if clients of this driver are still
712 * attached. If so, detach them to be able to kill the driver
715 if (driver->detach_adapter) {
716 if (driver->detach_adapter(adapter))
717 dev_err(&adapter->dev,
718 "detach_adapter failed for driver [%s]\n",
719 driver->driver.name);
721 struct list_head *item, *_n;
722 struct i2c_client *client;
724 list_for_each_safe(item, _n, &adapter->clients) {
725 client = list_entry(item, struct i2c_client, list);
726 if (client->driver != driver)
728 dev_dbg(&adapter->dev,
729 "detaching client [%s] at 0x%02x\n",
730 client->name, client->addr);
731 if (driver->detach_client(client))
732 dev_err(&adapter->dev, "detach_client "
733 "failed for client [%s] at 0x%02x\n",
734 client->name, client->addr);
742 * i2c_del_driver - unregister I2C driver
743 * @driver: the driver being unregistered
746 void i2c_del_driver(struct i2c_driver *driver)
748 mutex_lock(&core_lock);
750 /* new-style driver? */
751 if (is_newstyle_driver(driver))
754 class_for_each_device(&i2c_adapter_class, driver, __detach_adapter);
757 driver_unregister(&driver->driver);
758 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
760 mutex_unlock(&core_lock);
762 EXPORT_SYMBOL(i2c_del_driver);
764 /* ------------------------------------------------------------------------- */
766 static int __i2c_check_addr(struct device *dev, void *addrp)
768 struct i2c_client *client = i2c_verify_client(dev);
769 int addr = *(int *)addrp;
771 if (client && client->addr == addr)
776 static int i2c_check_addr(struct i2c_adapter *adapter, int addr)
778 return device_for_each_child(&adapter->dev, &addr, __i2c_check_addr);
781 int i2c_attach_client(struct i2c_client *client)
783 struct i2c_adapter *adapter = client->adapter;
786 client->dev.parent = &client->adapter->dev;
787 client->dev.bus = &i2c_bus_type;
790 client->dev.driver = &client->driver->driver;
792 if (client->driver && !is_newstyle_driver(client->driver)) {
793 client->dev.release = i2c_client_release;
794 client->dev.uevent_suppress = 1;
796 client->dev.release = i2c_client_dev_release;
798 snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id),
799 "%d-%04x", i2c_adapter_id(adapter), client->addr);
800 res = device_register(&client->dev);
804 mutex_lock(&adapter->clist_lock);
805 list_add_tail(&client->list, &adapter->clients);
806 mutex_unlock(&adapter->clist_lock);
808 dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n",
809 client->name, client->dev.bus_id);
811 if (adapter->client_register) {
812 if (adapter->client_register(client)) {
813 dev_dbg(&adapter->dev, "client_register "
814 "failed for client [%s] at 0x%02x\n",
815 client->name, client->addr);
822 dev_err(&adapter->dev, "Failed to attach i2c client %s at 0x%02x "
823 "(%d)\n", client->name, client->addr, res);
826 EXPORT_SYMBOL(i2c_attach_client);
828 int i2c_detach_client(struct i2c_client *client)
830 struct i2c_adapter *adapter = client->adapter;
833 if (adapter->client_unregister) {
834 res = adapter->client_unregister(client);
836 dev_err(&client->dev,
837 "client_unregister [%s] failed, "
838 "client not detached\n", client->name);
843 mutex_lock(&adapter->clist_lock);
844 list_del(&client->list);
845 mutex_unlock(&adapter->clist_lock);
847 init_completion(&client->released);
848 device_unregister(&client->dev);
849 wait_for_completion(&client->released);
854 EXPORT_SYMBOL(i2c_detach_client);
857 * i2c_use_client - increments the reference count of the i2c client structure
858 * @client: the client being referenced
860 * Each live reference to a client should be refcounted. The driver model does
861 * that automatically as part of driver binding, so that most drivers don't
862 * need to do this explicitly: they hold a reference until they're unbound
865 * A pointer to the client with the incremented reference counter is returned.
867 struct i2c_client *i2c_use_client(struct i2c_client *client)
869 get_device(&client->dev);
872 EXPORT_SYMBOL(i2c_use_client);
875 * i2c_release_client - release a use of the i2c client structure
876 * @client: the client being no longer referenced
878 * Must be called when a user of a client is finished with it.
880 void i2c_release_client(struct i2c_client *client)
882 put_device(&client->dev);
884 EXPORT_SYMBOL(i2c_release_client);
891 static int i2c_cmd(struct device *dev, void *_arg)
893 struct i2c_client *client = i2c_verify_client(dev);
894 struct i2c_cmd_arg *arg = _arg;
896 if (client && client->driver && client->driver->command)
897 client->driver->command(client, arg->cmd, arg->arg);
901 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
903 struct i2c_cmd_arg cmd_arg;
907 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
909 EXPORT_SYMBOL(i2c_clients_command);
911 static int __init i2c_init(void)
915 retval = bus_register(&i2c_bus_type);
918 retval = class_register(&i2c_adapter_class);
921 retval = i2c_add_driver(&dummy_driver);
927 class_unregister(&i2c_adapter_class);
929 bus_unregister(&i2c_bus_type);
933 static void __exit i2c_exit(void)
935 i2c_del_driver(&dummy_driver);
936 class_unregister(&i2c_adapter_class);
937 bus_unregister(&i2c_bus_type);
940 subsys_initcall(i2c_init);
941 module_exit(i2c_exit);
943 /* ----------------------------------------------------
944 * the functional interface to the i2c busses.
945 * ----------------------------------------------------
948 int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)
952 if (adap->algo->master_xfer) {
954 for (ret = 0; ret < num; ret++) {
955 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
956 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
957 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
958 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
962 if (in_atomic() || irqs_disabled()) {
963 ret = mutex_trylock(&adap->bus_lock);
965 /* I2C activity is ongoing. */
968 mutex_lock_nested(&adap->bus_lock, adap->level);
971 ret = adap->algo->master_xfer(adap,msgs,num);
972 mutex_unlock(&adap->bus_lock);
976 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
980 EXPORT_SYMBOL(i2c_transfer);
982 int i2c_master_send(struct i2c_client *client,const char *buf ,int count)
985 struct i2c_adapter *adap=client->adapter;
988 msg.addr = client->addr;
989 msg.flags = client->flags & I2C_M_TEN;
991 msg.buf = (char *)buf;
993 ret = i2c_transfer(adap, &msg, 1);
995 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
996 transmitted, else error code. */
997 return (ret == 1) ? count : ret;
999 EXPORT_SYMBOL(i2c_master_send);
1001 int i2c_master_recv(struct i2c_client *client, char *buf ,int count)
1003 struct i2c_adapter *adap=client->adapter;
1007 msg.addr = client->addr;
1008 msg.flags = client->flags & I2C_M_TEN;
1009 msg.flags |= I2C_M_RD;
1013 ret = i2c_transfer(adap, &msg, 1);
1015 /* If everything went ok (i.e. 1 msg transmitted), return #bytes
1016 transmitted, else error code. */
1017 return (ret == 1) ? count : ret;
1019 EXPORT_SYMBOL(i2c_master_recv);
1021 /* ----------------------------------------------------
1022 * the i2c address scanning function
1023 * Will not work for 10-bit addresses!
1024 * ----------------------------------------------------
1026 static int i2c_probe_address(struct i2c_adapter *adapter, int addr, int kind,
1027 int (*found_proc) (struct i2c_adapter *, int, int))
1031 /* Make sure the address is valid */
1032 if (addr < 0x03 || addr > 0x77) {
1033 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
1038 /* Skip if already in use */
1039 if (i2c_check_addr(adapter, addr))
1042 /* Make sure there is something at this address, unless forced */
1044 if (i2c_smbus_xfer(adapter, addr, 0, 0, 0,
1045 I2C_SMBUS_QUICK, NULL) < 0)
1048 /* prevent 24RF08 corruption */
1049 if ((addr & ~0x0f) == 0x50)
1050 i2c_smbus_xfer(adapter, addr, 0, 0, 0,
1051 I2C_SMBUS_QUICK, NULL);
1054 /* Finally call the custom detection function */
1055 err = found_proc(adapter, addr, kind);
1056 /* -ENODEV can be returned if there is a chip at the given address
1057 but it isn't supported by this chip driver. We catch it here as
1058 this isn't an error. */
1063 dev_warn(&adapter->dev, "Client creation failed at 0x%x (%d)\n",
1068 int i2c_probe(struct i2c_adapter *adapter,
1069 const struct i2c_client_address_data *address_data,
1070 int (*found_proc) (struct i2c_adapter *, int, int))
1073 int adap_id = i2c_adapter_id(adapter);
1075 /* Force entries are done first, and are not affected by ignore
1077 if (address_data->forces) {
1078 const unsigned short * const *forces = address_data->forces;
1081 for (kind = 0; forces[kind]; kind++) {
1082 for (i = 0; forces[kind][i] != I2C_CLIENT_END;
1084 if (forces[kind][i] == adap_id
1085 || forces[kind][i] == ANY_I2C_BUS) {
1086 dev_dbg(&adapter->dev, "found force "
1087 "parameter for adapter %d, "
1088 "addr 0x%02x, kind %d\n",
1089 adap_id, forces[kind][i + 1],
1091 err = i2c_probe_address(adapter,
1092 forces[kind][i + 1],
1101 /* Stop here if we can't use SMBUS_QUICK */
1102 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_QUICK)) {
1103 if (address_data->probe[0] == I2C_CLIENT_END
1104 && address_data->normal_i2c[0] == I2C_CLIENT_END)
1107 dev_warn(&adapter->dev, "SMBus Quick command not supported, "
1108 "can't probe for chips\n");
1112 /* Probe entries are done second, and are not affected by ignore
1114 for (i = 0; address_data->probe[i] != I2C_CLIENT_END; i += 2) {
1115 if (address_data->probe[i] == adap_id
1116 || address_data->probe[i] == ANY_I2C_BUS) {
1117 dev_dbg(&adapter->dev, "found probe parameter for "
1118 "adapter %d, addr 0x%02x\n", adap_id,
1119 address_data->probe[i + 1]);
1120 err = i2c_probe_address(adapter,
1121 address_data->probe[i + 1],
1128 /* Normal entries are done last, unless shadowed by an ignore entry */
1129 for (i = 0; address_data->normal_i2c[i] != I2C_CLIENT_END; i += 1) {
1133 for (j = 0; address_data->ignore[j] != I2C_CLIENT_END;
1135 if ((address_data->ignore[j] == adap_id ||
1136 address_data->ignore[j] == ANY_I2C_BUS)
1137 && address_data->ignore[j + 1]
1138 == address_data->normal_i2c[i]) {
1139 dev_dbg(&adapter->dev, "found ignore "
1140 "parameter for adapter %d, "
1141 "addr 0x%02x\n", adap_id,
1142 address_data->ignore[j + 1]);
1150 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
1151 "addr 0x%02x\n", adap_id,
1152 address_data->normal_i2c[i]);
1153 err = i2c_probe_address(adapter, address_data->normal_i2c[i],
1161 EXPORT_SYMBOL(i2c_probe);
1164 i2c_new_probed_device(struct i2c_adapter *adap,
1165 struct i2c_board_info *info,
1166 unsigned short const *addr_list)
1170 /* Stop here if the bus doesn't support probing */
1171 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) {
1172 dev_err(&adap->dev, "Probing not supported\n");
1176 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
1177 /* Check address validity */
1178 if (addr_list[i] < 0x03 || addr_list[i] > 0x77) {
1179 dev_warn(&adap->dev, "Invalid 7-bit address "
1180 "0x%02x\n", addr_list[i]);
1184 /* Check address availability */
1185 if (i2c_check_addr(adap, addr_list[i])) {
1186 dev_dbg(&adap->dev, "Address 0x%02x already in "
1187 "use, not probing\n", addr_list[i]);
1191 /* Test address responsiveness
1192 The default probe method is a quick write, but it is known
1193 to corrupt the 24RF08 EEPROMs due to a state machine bug,
1194 and could also irreversibly write-protect some EEPROMs, so
1195 for address ranges 0x30-0x37 and 0x50-0x5f, we use a byte
1196 read instead. Also, some bus drivers don't implement
1197 quick write, so we fallback to a byte read it that case
1199 if ((addr_list[i] & ~0x07) == 0x30
1200 || (addr_list[i] & ~0x0f) == 0x50
1201 || !i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) {
1202 if (i2c_smbus_xfer(adap, addr_list[i], 0,
1204 I2C_SMBUS_BYTE, NULL) >= 0)
1207 if (i2c_smbus_xfer(adap, addr_list[i], 0,
1209 I2C_SMBUS_QUICK, NULL) >= 0)
1214 if (addr_list[i] == I2C_CLIENT_END) {
1215 dev_dbg(&adap->dev, "Probing failed, no device found\n");
1219 info->addr = addr_list[i];
1220 return i2c_new_device(adap, info);
1222 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
1224 struct i2c_adapter* i2c_get_adapter(int id)
1226 struct i2c_adapter *adapter;
1228 mutex_lock(&core_lock);
1229 adapter = (struct i2c_adapter *)idr_find(&i2c_adapter_idr, id);
1230 if (adapter && !try_module_get(adapter->owner))
1233 mutex_unlock(&core_lock);
1236 EXPORT_SYMBOL(i2c_get_adapter);
1238 void i2c_put_adapter(struct i2c_adapter *adap)
1240 module_put(adap->owner);
1242 EXPORT_SYMBOL(i2c_put_adapter);
1244 /* The SMBus parts */
1246 #define POLY (0x1070U << 3)
1252 for(i = 0; i < 8; i++) {
1257 return (u8)(data >> 8);
1260 /* Incremental CRC8 over count bytes in the array pointed to by p */
1261 static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
1265 for(i = 0; i < count; i++)
1266 crc = crc8((crc ^ p[i]) << 8);
1270 /* Assume a 7-bit address, which is reasonable for SMBus */
1271 static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
1273 /* The address will be sent first */
1274 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
1275 pec = i2c_smbus_pec(pec, &addr, 1);
1277 /* The data buffer follows */
1278 return i2c_smbus_pec(pec, msg->buf, msg->len);
1281 /* Used for write only transactions */
1282 static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
1284 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
1288 /* Return <0 on CRC error
1289 If there was a write before this read (most cases) we need to take the
1290 partial CRC from the write part into account.
1291 Note that this function does modify the message (we need to decrease the
1292 message length to hide the CRC byte from the caller). */
1293 static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
1295 u8 rpec = msg->buf[--msg->len];
1296 cpec = i2c_smbus_msg_pec(cpec, msg);
1299 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
1306 s32 i2c_smbus_read_byte(struct i2c_client *client)
1308 union i2c_smbus_data data;
1311 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1313 I2C_SMBUS_BYTE, &data);
1314 return (status < 0) ? status : data.byte;
1316 EXPORT_SYMBOL(i2c_smbus_read_byte);
1318 s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
1320 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1321 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
1323 EXPORT_SYMBOL(i2c_smbus_write_byte);
1325 s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
1327 union i2c_smbus_data data;
1330 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1331 I2C_SMBUS_READ, command,
1332 I2C_SMBUS_BYTE_DATA, &data);
1333 return (status < 0) ? status : data.byte;
1335 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
1337 s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
1339 union i2c_smbus_data data;
1341 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1342 I2C_SMBUS_WRITE,command,
1343 I2C_SMBUS_BYTE_DATA,&data);
1345 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
1347 s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
1349 union i2c_smbus_data data;
1352 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1353 I2C_SMBUS_READ, command,
1354 I2C_SMBUS_WORD_DATA, &data);
1355 return (status < 0) ? status : data.word;
1357 EXPORT_SYMBOL(i2c_smbus_read_word_data);
1359 s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
1361 union i2c_smbus_data data;
1363 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1364 I2C_SMBUS_WRITE,command,
1365 I2C_SMBUS_WORD_DATA,&data);
1367 EXPORT_SYMBOL(i2c_smbus_write_word_data);
1370 * i2c_smbus_read_block_data - SMBus block read request
1371 * @client: Handle to slave device
1372 * @command: Command byte issued to let the slave know what data should
1374 * @values: Byte array into which data will be read; big enough to hold
1375 * the data returned by the slave. SMBus allows at most 32 bytes.
1377 * Returns the number of bytes read in the slave's response, else a
1378 * negative number to indicate some kind of error.
1380 * Note that using this function requires that the client's adapter support
1381 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
1382 * support this; its emulation through I2C messaging relies on a specific
1383 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
1385 s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
1388 union i2c_smbus_data data;
1391 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1392 I2C_SMBUS_READ, command,
1393 I2C_SMBUS_BLOCK_DATA, &data);
1397 memcpy(values, &data.block[1], data.block[0]);
1398 return data.block[0];
1400 EXPORT_SYMBOL(i2c_smbus_read_block_data);
1402 s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
1403 u8 length, const u8 *values)
1405 union i2c_smbus_data data;
1407 if (length > I2C_SMBUS_BLOCK_MAX)
1408 length = I2C_SMBUS_BLOCK_MAX;
1409 data.block[0] = length;
1410 memcpy(&data.block[1], values, length);
1411 return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
1412 I2C_SMBUS_WRITE,command,
1413 I2C_SMBUS_BLOCK_DATA,&data);
1415 EXPORT_SYMBOL(i2c_smbus_write_block_data);
1417 /* Returns the number of read bytes */
1418 s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
1419 u8 length, u8 *values)
1421 union i2c_smbus_data data;
1424 if (length > I2C_SMBUS_BLOCK_MAX)
1425 length = I2C_SMBUS_BLOCK_MAX;
1426 data.block[0] = length;
1427 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1428 I2C_SMBUS_READ, command,
1429 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1433 memcpy(values, &data.block[1], data.block[0]);
1434 return data.block[0];
1436 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
1438 s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client, u8 command,
1439 u8 length, const u8 *values)
1441 union i2c_smbus_data data;
1443 if (length > I2C_SMBUS_BLOCK_MAX)
1444 length = I2C_SMBUS_BLOCK_MAX;
1445 data.block[0] = length;
1446 memcpy(data.block + 1, values, length);
1447 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
1448 I2C_SMBUS_WRITE, command,
1449 I2C_SMBUS_I2C_BLOCK_DATA, &data);
1451 EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
1453 /* Simulate a SMBus command using the i2c protocol
1454 No checking of parameters is done! */
1455 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
1456 unsigned short flags,
1457 char read_write, u8 command, int size,
1458 union i2c_smbus_data * data)
1460 /* So we need to generate a series of msgs. In the case of writing, we
1461 need to use only one message; when reading, we need two. We initialize
1462 most things with sane defaults, to keep the code below somewhat
1464 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
1465 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
1466 int num = read_write == I2C_SMBUS_READ?2:1;
1467 struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
1468 { addr, flags | I2C_M_RD, 0, msgbuf1 }
1474 msgbuf0[0] = command;
1476 case I2C_SMBUS_QUICK:
1478 /* Special case: The read/write field is used as data */
1479 msg[0].flags = flags | (read_write==I2C_SMBUS_READ)?I2C_M_RD:0;
1482 case I2C_SMBUS_BYTE:
1483 if (read_write == I2C_SMBUS_READ) {
1484 /* Special case: only a read! */
1485 msg[0].flags = I2C_M_RD | flags;
1489 case I2C_SMBUS_BYTE_DATA:
1490 if (read_write == I2C_SMBUS_READ)
1494 msgbuf0[1] = data->byte;
1497 case I2C_SMBUS_WORD_DATA:
1498 if (read_write == I2C_SMBUS_READ)
1502 msgbuf0[1] = data->word & 0xff;
1503 msgbuf0[2] = data->word >> 8;
1506 case I2C_SMBUS_PROC_CALL:
1507 num = 2; /* Special case */
1508 read_write = I2C_SMBUS_READ;
1511 msgbuf0[1] = data->word & 0xff;
1512 msgbuf0[2] = data->word >> 8;
1514 case I2C_SMBUS_BLOCK_DATA:
1515 if (read_write == I2C_SMBUS_READ) {
1516 msg[1].flags |= I2C_M_RECV_LEN;
1517 msg[1].len = 1; /* block length will be added by
1518 the underlying bus driver */
1520 msg[0].len = data->block[0] + 2;
1521 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
1522 dev_err(&adapter->dev,
1523 "Invalid block write size %d\n",
1527 for (i = 1; i < msg[0].len; i++)
1528 msgbuf0[i] = data->block[i-1];
1531 case I2C_SMBUS_BLOCK_PROC_CALL:
1532 num = 2; /* Another special case */
1533 read_write = I2C_SMBUS_READ;
1534 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
1535 dev_err(&adapter->dev,
1536 "Invalid block write size %d\n",
1540 msg[0].len = data->block[0] + 2;
1541 for (i = 1; i < msg[0].len; i++)
1542 msgbuf0[i] = data->block[i-1];
1543 msg[1].flags |= I2C_M_RECV_LEN;
1544 msg[1].len = 1; /* block length will be added by
1545 the underlying bus driver */
1547 case I2C_SMBUS_I2C_BLOCK_DATA:
1548 if (read_write == I2C_SMBUS_READ) {
1549 msg[1].len = data->block[0];
1551 msg[0].len = data->block[0] + 1;
1552 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
1553 dev_err(&adapter->dev,
1554 "Invalid block write size %d\n",
1558 for (i = 1; i <= data->block[0]; i++)
1559 msgbuf0[i] = data->block[i];
1563 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
1567 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
1568 && size != I2C_SMBUS_I2C_BLOCK_DATA);
1570 /* Compute PEC if first message is a write */
1571 if (!(msg[0].flags & I2C_M_RD)) {
1572 if (num == 1) /* Write only */
1573 i2c_smbus_add_pec(&msg[0]);
1574 else /* Write followed by read */
1575 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
1577 /* Ask for PEC if last message is a read */
1578 if (msg[num-1].flags & I2C_M_RD)
1582 status = i2c_transfer(adapter, msg, num);
1586 /* Check PEC if last message is a read */
1587 if (i && (msg[num-1].flags & I2C_M_RD)) {
1588 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
1593 if (read_write == I2C_SMBUS_READ)
1595 case I2C_SMBUS_BYTE:
1596 data->byte = msgbuf0[0];
1598 case I2C_SMBUS_BYTE_DATA:
1599 data->byte = msgbuf1[0];
1601 case I2C_SMBUS_WORD_DATA:
1602 case I2C_SMBUS_PROC_CALL:
1603 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
1605 case I2C_SMBUS_I2C_BLOCK_DATA:
1606 for (i = 0; i < data->block[0]; i++)
1607 data->block[i+1] = msgbuf1[i];
1609 case I2C_SMBUS_BLOCK_DATA:
1610 case I2C_SMBUS_BLOCK_PROC_CALL:
1611 for (i = 0; i < msgbuf1[0] + 1; i++)
1612 data->block[i] = msgbuf1[i];
1619 s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
1620 char read_write, u8 command, int size,
1621 union i2c_smbus_data * data)
1625 flags &= I2C_M_TEN | I2C_CLIENT_PEC;
1627 if (adapter->algo->smbus_xfer) {
1628 mutex_lock(&adapter->bus_lock);
1629 res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write,
1631 mutex_unlock(&adapter->bus_lock);
1633 res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
1638 EXPORT_SYMBOL(i2c_smbus_xfer);
1640 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
1641 MODULE_DESCRIPTION("I2C-Bus main module");
1642 MODULE_LICENSE("GPL");