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![Jean Delvare](/assets/img/avatar_default.png)
If kernel is compiled with CONFIG_PROVE_LOCKING the validator raises an error when a multiplexer is removed via sysfs and sub-clients are connected to it. This is a false positive. Documentation/lockdep-design.txt recommends to handle this via calls to mutex_lock_nested(). Based on an earlier fix from Michael Lawnick. Note that the extra code resolves to nothing unless CONFIG_DEBUG_LOCK_ALLOC=y. Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Michael Lawnick <ml.lawnick@gmx.de>
2199 lines
60 KiB
C
2199 lines
60 KiB
C
/* i2c-core.c - a device driver for the iic-bus interface */
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/* ------------------------------------------------------------------------- */
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/* Copyright (C) 1995-99 Simon G. Vogl
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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MA 02110-1301 USA. */
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/* ------------------------------------------------------------------------- */
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/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
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All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
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SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
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Jean Delvare <khali@linux-fr.org>
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Mux support by Rodolfo Giometti <giometti@enneenne.com> and
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Michael Lawnick <michael.lawnick.ext@nsn.com> */
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/idr.h>
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#include <linux/mutex.h>
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#include <linux/of_device.h>
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#include <linux/completion.h>
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#include <linux/hardirq.h>
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#include <linux/irqflags.h>
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#include <linux/rwsem.h>
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#include <linux/pm_runtime.h>
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#include <asm/uaccess.h>
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#include "i2c-core.h"
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/* core_lock protects i2c_adapter_idr, and guarantees
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that device detection, deletion of detected devices, and attach_adapter
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and detach_adapter calls are serialized */
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static DEFINE_MUTEX(core_lock);
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static DEFINE_IDR(i2c_adapter_idr);
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static struct device_type i2c_client_type;
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static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
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/* ------------------------------------------------------------------------- */
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static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
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const struct i2c_client *client)
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{
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while (id->name[0]) {
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if (strcmp(client->name, id->name) == 0)
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return id;
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id++;
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}
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return NULL;
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}
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static int i2c_device_match(struct device *dev, struct device_driver *drv)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct i2c_driver *driver;
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if (!client)
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return 0;
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/* Attempt an OF style match */
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if (of_driver_match_device(dev, drv))
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return 1;
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driver = to_i2c_driver(drv);
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/* match on an id table if there is one */
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if (driver->id_table)
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return i2c_match_id(driver->id_table, client) != NULL;
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return 0;
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}
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#ifdef CONFIG_HOTPLUG
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/* uevent helps with hotplug: modprobe -q $(MODALIAS) */
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static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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struct i2c_client *client = to_i2c_client(dev);
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if (add_uevent_var(env, "MODALIAS=%s%s",
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I2C_MODULE_PREFIX, client->name))
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return -ENOMEM;
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dev_dbg(dev, "uevent\n");
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return 0;
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}
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#else
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#define i2c_device_uevent NULL
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#endif /* CONFIG_HOTPLUG */
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static int i2c_device_probe(struct device *dev)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct i2c_driver *driver;
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int status;
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if (!client)
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return 0;
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driver = to_i2c_driver(dev->driver);
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if (!driver->probe || !driver->id_table)
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return -ENODEV;
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client->driver = driver;
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if (!device_can_wakeup(&client->dev))
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device_init_wakeup(&client->dev,
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client->flags & I2C_CLIENT_WAKE);
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dev_dbg(dev, "probe\n");
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status = driver->probe(client, i2c_match_id(driver->id_table, client));
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if (status) {
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client->driver = NULL;
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i2c_set_clientdata(client, NULL);
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}
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return status;
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}
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static int i2c_device_remove(struct device *dev)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct i2c_driver *driver;
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int status;
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if (!client || !dev->driver)
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return 0;
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driver = to_i2c_driver(dev->driver);
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if (driver->remove) {
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dev_dbg(dev, "remove\n");
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status = driver->remove(client);
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} else {
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dev->driver = NULL;
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status = 0;
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}
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if (status == 0) {
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client->driver = NULL;
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i2c_set_clientdata(client, NULL);
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}
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return status;
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}
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static void i2c_device_shutdown(struct device *dev)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct i2c_driver *driver;
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if (!client || !dev->driver)
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return;
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driver = to_i2c_driver(dev->driver);
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if (driver->shutdown)
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driver->shutdown(client);
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}
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#ifdef CONFIG_PM_SLEEP
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static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct i2c_driver *driver;
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if (!client || !dev->driver)
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return 0;
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driver = to_i2c_driver(dev->driver);
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if (!driver->suspend)
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return 0;
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return driver->suspend(client, mesg);
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}
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static int i2c_legacy_resume(struct device *dev)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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struct i2c_driver *driver;
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if (!client || !dev->driver)
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return 0;
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driver = to_i2c_driver(dev->driver);
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if (!driver->resume)
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return 0;
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return driver->resume(client);
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}
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static int i2c_device_pm_suspend(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_suspend(dev);
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else
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return i2c_legacy_suspend(dev, PMSG_SUSPEND);
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}
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static int i2c_device_pm_resume(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_resume(dev);
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else
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return i2c_legacy_resume(dev);
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}
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static int i2c_device_pm_freeze(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_freeze(dev);
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else
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return i2c_legacy_suspend(dev, PMSG_FREEZE);
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}
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static int i2c_device_pm_thaw(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_thaw(dev);
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else
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return i2c_legacy_resume(dev);
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}
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static int i2c_device_pm_poweroff(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_poweroff(dev);
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else
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return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
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}
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static int i2c_device_pm_restore(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_restore(dev);
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else
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return i2c_legacy_resume(dev);
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}
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#else /* !CONFIG_PM_SLEEP */
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#define i2c_device_pm_suspend NULL
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#define i2c_device_pm_resume NULL
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#define i2c_device_pm_freeze NULL
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#define i2c_device_pm_thaw NULL
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#define i2c_device_pm_poweroff NULL
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#define i2c_device_pm_restore NULL
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#endif /* !CONFIG_PM_SLEEP */
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static void i2c_client_dev_release(struct device *dev)
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{
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kfree(to_i2c_client(dev));
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}
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static ssize_t
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show_name(struct device *dev, struct device_attribute *attr, char *buf)
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{
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return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
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to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
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}
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static ssize_t
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show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
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{
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struct i2c_client *client = to_i2c_client(dev);
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return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
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}
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static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
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static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
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static struct attribute *i2c_dev_attrs[] = {
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&dev_attr_name.attr,
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/* modalias helps coldplug: modprobe $(cat .../modalias) */
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&dev_attr_modalias.attr,
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NULL
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};
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static struct attribute_group i2c_dev_attr_group = {
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.attrs = i2c_dev_attrs,
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};
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static const struct attribute_group *i2c_dev_attr_groups[] = {
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&i2c_dev_attr_group,
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NULL
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};
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static const struct dev_pm_ops i2c_device_pm_ops = {
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.suspend = i2c_device_pm_suspend,
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.resume = i2c_device_pm_resume,
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.freeze = i2c_device_pm_freeze,
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.thaw = i2c_device_pm_thaw,
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.poweroff = i2c_device_pm_poweroff,
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.restore = i2c_device_pm_restore,
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SET_RUNTIME_PM_OPS(
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pm_generic_runtime_suspend,
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pm_generic_runtime_resume,
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pm_generic_runtime_idle
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)
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};
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struct bus_type i2c_bus_type = {
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.name = "i2c",
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.match = i2c_device_match,
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.probe = i2c_device_probe,
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.remove = i2c_device_remove,
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.shutdown = i2c_device_shutdown,
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.pm = &i2c_device_pm_ops,
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};
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EXPORT_SYMBOL_GPL(i2c_bus_type);
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static struct device_type i2c_client_type = {
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.groups = i2c_dev_attr_groups,
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.uevent = i2c_device_uevent,
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.release = i2c_client_dev_release,
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};
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/**
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* i2c_verify_client - return parameter as i2c_client, or NULL
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* @dev: device, probably from some driver model iterator
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*
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* When traversing the driver model tree, perhaps using driver model
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* iterators like @device_for_each_child(), you can't assume very much
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* about the nodes you find. Use this function to avoid oopses caused
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* by wrongly treating some non-I2C device as an i2c_client.
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*/
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struct i2c_client *i2c_verify_client(struct device *dev)
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{
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return (dev->type == &i2c_client_type)
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? to_i2c_client(dev)
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: NULL;
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}
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EXPORT_SYMBOL(i2c_verify_client);
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/* This is a permissive address validity check, I2C address map constraints
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* are purposely not enforced, except for the general call address. */
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static int i2c_check_client_addr_validity(const struct i2c_client *client)
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{
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if (client->flags & I2C_CLIENT_TEN) {
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/* 10-bit address, all values are valid */
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if (client->addr > 0x3ff)
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return -EINVAL;
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} else {
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/* 7-bit address, reject the general call address */
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if (client->addr == 0x00 || client->addr > 0x7f)
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return -EINVAL;
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}
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return 0;
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}
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/* And this is a strict address validity check, used when probing. If a
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* device uses a reserved address, then it shouldn't be probed. 7-bit
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* addressing is assumed, 10-bit address devices are rare and should be
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* explicitly enumerated. */
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static int i2c_check_addr_validity(unsigned short addr)
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{
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/*
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* Reserved addresses per I2C specification:
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* 0x00 General call address / START byte
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* 0x01 CBUS address
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* 0x02 Reserved for different bus format
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* 0x03 Reserved for future purposes
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* 0x04-0x07 Hs-mode master code
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* 0x78-0x7b 10-bit slave addressing
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* 0x7c-0x7f Reserved for future purposes
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*/
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if (addr < 0x08 || addr > 0x77)
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return -EINVAL;
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return 0;
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}
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static int __i2c_check_addr_busy(struct device *dev, void *addrp)
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{
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struct i2c_client *client = i2c_verify_client(dev);
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int addr = *(int *)addrp;
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if (client && client->addr == addr)
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return -EBUSY;
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return 0;
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}
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/* walk up mux tree */
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static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
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{
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struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
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int result;
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result = device_for_each_child(&adapter->dev, &addr,
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__i2c_check_addr_busy);
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if (!result && parent)
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result = i2c_check_mux_parents(parent, addr);
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return result;
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}
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/* recurse down mux tree */
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static int i2c_check_mux_children(struct device *dev, void *addrp)
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{
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int result;
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if (dev->type == &i2c_adapter_type)
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result = device_for_each_child(dev, addrp,
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i2c_check_mux_children);
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else
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result = __i2c_check_addr_busy(dev, addrp);
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return result;
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}
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static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
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{
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struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
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int result = 0;
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if (parent)
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result = i2c_check_mux_parents(parent, addr);
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if (!result)
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result = device_for_each_child(&adapter->dev, &addr,
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i2c_check_mux_children);
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return result;
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}
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/**
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* i2c_lock_adapter - Get exclusive access to an I2C bus segment
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* @adapter: Target I2C bus segment
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*/
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void i2c_lock_adapter(struct i2c_adapter *adapter)
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{
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struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
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if (parent)
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i2c_lock_adapter(parent);
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else
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rt_mutex_lock(&adapter->bus_lock);
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}
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EXPORT_SYMBOL_GPL(i2c_lock_adapter);
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/**
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* i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
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* @adapter: Target I2C bus segment
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*/
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static int i2c_trylock_adapter(struct i2c_adapter *adapter)
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{
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struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
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if (parent)
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return i2c_trylock_adapter(parent);
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else
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return rt_mutex_trylock(&adapter->bus_lock);
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}
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/**
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* i2c_unlock_adapter - Release exclusive access to an I2C bus segment
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* @adapter: Target I2C bus segment
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*/
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void i2c_unlock_adapter(struct i2c_adapter *adapter)
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{
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struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
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if (parent)
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i2c_unlock_adapter(parent);
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else
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rt_mutex_unlock(&adapter->bus_lock);
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}
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EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
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/**
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* i2c_new_device - instantiate an i2c device
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* @adap: the adapter managing the device
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* @info: describes one I2C device; bus_num is ignored
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* Context: can sleep
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*
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* Create an i2c device. Binding is handled through driver model
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* probe()/remove() methods. A driver may be bound to this device when we
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* return from this function, or any later moment (e.g. maybe hotplugging will
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* load the driver module). This call is not appropriate for use by mainboard
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* initialization logic, which usually runs during an arch_initcall() long
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* before any i2c_adapter could exist.
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*
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* This returns the new i2c client, which may be saved for later use with
|
|
* i2c_unregister_device(); or NULL to indicate an error.
|
|
*/
|
|
struct i2c_client *
|
|
i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
|
|
{
|
|
struct i2c_client *client;
|
|
int status;
|
|
|
|
client = kzalloc(sizeof *client, GFP_KERNEL);
|
|
if (!client)
|
|
return NULL;
|
|
|
|
client->adapter = adap;
|
|
|
|
client->dev.platform_data = info->platform_data;
|
|
|
|
if (info->archdata)
|
|
client->dev.archdata = *info->archdata;
|
|
|
|
client->flags = info->flags;
|
|
client->addr = info->addr;
|
|
client->irq = info->irq;
|
|
|
|
strlcpy(client->name, info->type, sizeof(client->name));
|
|
|
|
/* Check for address validity */
|
|
status = i2c_check_client_addr_validity(client);
|
|
if (status) {
|
|
dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
|
|
client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
|
|
goto out_err_silent;
|
|
}
|
|
|
|
/* Check for address business */
|
|
status = i2c_check_addr_busy(adap, client->addr);
|
|
if (status)
|
|
goto out_err;
|
|
|
|
client->dev.parent = &client->adapter->dev;
|
|
client->dev.bus = &i2c_bus_type;
|
|
client->dev.type = &i2c_client_type;
|
|
client->dev.of_node = info->of_node;
|
|
|
|
/* For 10-bit clients, add an arbitrary offset to avoid collisions */
|
|
dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
|
|
client->addr | ((client->flags & I2C_CLIENT_TEN)
|
|
? 0xa000 : 0));
|
|
status = device_register(&client->dev);
|
|
if (status)
|
|
goto out_err;
|
|
|
|
dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
|
|
client->name, dev_name(&client->dev));
|
|
|
|
return client;
|
|
|
|
out_err:
|
|
dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
|
|
"(%d)\n", client->name, client->addr, status);
|
|
out_err_silent:
|
|
kfree(client);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_new_device);
|
|
|
|
|
|
/**
|
|
* i2c_unregister_device - reverse effect of i2c_new_device()
|
|
* @client: value returned from i2c_new_device()
|
|
* Context: can sleep
|
|
*/
|
|
void i2c_unregister_device(struct i2c_client *client)
|
|
{
|
|
device_unregister(&client->dev);
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_unregister_device);
|
|
|
|
|
|
static const struct i2c_device_id dummy_id[] = {
|
|
{ "dummy", 0 },
|
|
{ },
|
|
};
|
|
|
|
static int dummy_probe(struct i2c_client *client,
|
|
const struct i2c_device_id *id)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static int dummy_remove(struct i2c_client *client)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static struct i2c_driver dummy_driver = {
|
|
.driver.name = "dummy",
|
|
.probe = dummy_probe,
|
|
.remove = dummy_remove,
|
|
.id_table = dummy_id,
|
|
};
|
|
|
|
/**
|
|
* i2c_new_dummy - return a new i2c device bound to a dummy driver
|
|
* @adapter: the adapter managing the device
|
|
* @address: seven bit address to be used
|
|
* Context: can sleep
|
|
*
|
|
* This returns an I2C client bound to the "dummy" driver, intended for use
|
|
* with devices that consume multiple addresses. Examples of such chips
|
|
* include various EEPROMS (like 24c04 and 24c08 models).
|
|
*
|
|
* These dummy devices have two main uses. First, most I2C and SMBus calls
|
|
* except i2c_transfer() need a client handle; the dummy will be that handle.
|
|
* And second, this prevents the specified address from being bound to a
|
|
* different driver.
|
|
*
|
|
* This returns the new i2c client, which should be saved for later use with
|
|
* i2c_unregister_device(); or NULL to indicate an error.
|
|
*/
|
|
struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
|
|
{
|
|
struct i2c_board_info info = {
|
|
I2C_BOARD_INFO("dummy", address),
|
|
};
|
|
|
|
return i2c_new_device(adapter, &info);
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_new_dummy);
|
|
|
|
/* ------------------------------------------------------------------------- */
|
|
|
|
/* I2C bus adapters -- one roots each I2C or SMBUS segment */
|
|
|
|
static void i2c_adapter_dev_release(struct device *dev)
|
|
{
|
|
struct i2c_adapter *adap = to_i2c_adapter(dev);
|
|
complete(&adap->dev_released);
|
|
}
|
|
|
|
/*
|
|
* This function is only needed for mutex_lock_nested, so it is never
|
|
* called unless locking correctness checking is enabled. Thus we
|
|
* make it inline to avoid a compiler warning. That's what gcc ends up
|
|
* doing anyway.
|
|
*/
|
|
static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
|
|
{
|
|
unsigned int depth = 0;
|
|
|
|
while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
|
|
depth++;
|
|
|
|
return depth;
|
|
}
|
|
|
|
/*
|
|
* Let users instantiate I2C devices through sysfs. This can be used when
|
|
* platform initialization code doesn't contain the proper data for
|
|
* whatever reason. Also useful for drivers that do device detection and
|
|
* detection fails, either because the device uses an unexpected address,
|
|
* or this is a compatible device with different ID register values.
|
|
*
|
|
* Parameter checking may look overzealous, but we really don't want
|
|
* the user to provide incorrect parameters.
|
|
*/
|
|
static ssize_t
|
|
i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct i2c_adapter *adap = to_i2c_adapter(dev);
|
|
struct i2c_board_info info;
|
|
struct i2c_client *client;
|
|
char *blank, end;
|
|
int res;
|
|
|
|
memset(&info, 0, sizeof(struct i2c_board_info));
|
|
|
|
blank = strchr(buf, ' ');
|
|
if (!blank) {
|
|
dev_err(dev, "%s: Missing parameters\n", "new_device");
|
|
return -EINVAL;
|
|
}
|
|
if (blank - buf > I2C_NAME_SIZE - 1) {
|
|
dev_err(dev, "%s: Invalid device name\n", "new_device");
|
|
return -EINVAL;
|
|
}
|
|
memcpy(info.type, buf, blank - buf);
|
|
|
|
/* Parse remaining parameters, reject extra parameters */
|
|
res = sscanf(++blank, "%hi%c", &info.addr, &end);
|
|
if (res < 1) {
|
|
dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
|
|
return -EINVAL;
|
|
}
|
|
if (res > 1 && end != '\n') {
|
|
dev_err(dev, "%s: Extra parameters\n", "new_device");
|
|
return -EINVAL;
|
|
}
|
|
|
|
client = i2c_new_device(adap, &info);
|
|
if (!client)
|
|
return -EINVAL;
|
|
|
|
/* Keep track of the added device */
|
|
mutex_lock(&adap->userspace_clients_lock);
|
|
list_add_tail(&client->detected, &adap->userspace_clients);
|
|
mutex_unlock(&adap->userspace_clients_lock);
|
|
dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
|
|
info.type, info.addr);
|
|
|
|
return count;
|
|
}
|
|
|
|
/*
|
|
* And of course let the users delete the devices they instantiated, if
|
|
* they got it wrong. This interface can only be used to delete devices
|
|
* instantiated by i2c_sysfs_new_device above. This guarantees that we
|
|
* don't delete devices to which some kernel code still has references.
|
|
*
|
|
* Parameter checking may look overzealous, but we really don't want
|
|
* the user to delete the wrong device.
|
|
*/
|
|
static ssize_t
|
|
i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
|
|
const char *buf, size_t count)
|
|
{
|
|
struct i2c_adapter *adap = to_i2c_adapter(dev);
|
|
struct i2c_client *client, *next;
|
|
unsigned short addr;
|
|
char end;
|
|
int res;
|
|
|
|
/* Parse parameters, reject extra parameters */
|
|
res = sscanf(buf, "%hi%c", &addr, &end);
|
|
if (res < 1) {
|
|
dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
|
|
return -EINVAL;
|
|
}
|
|
if (res > 1 && end != '\n') {
|
|
dev_err(dev, "%s: Extra parameters\n", "delete_device");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Make sure the device was added through sysfs */
|
|
res = -ENOENT;
|
|
mutex_lock_nested(&adap->userspace_clients_lock,
|
|
i2c_adapter_depth(adap));
|
|
list_for_each_entry_safe(client, next, &adap->userspace_clients,
|
|
detected) {
|
|
if (client->addr == addr) {
|
|
dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
|
|
"delete_device", client->name, client->addr);
|
|
|
|
list_del(&client->detected);
|
|
i2c_unregister_device(client);
|
|
res = count;
|
|
break;
|
|
}
|
|
}
|
|
mutex_unlock(&adap->userspace_clients_lock);
|
|
|
|
if (res < 0)
|
|
dev_err(dev, "%s: Can't find device in list\n",
|
|
"delete_device");
|
|
return res;
|
|
}
|
|
|
|
static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
|
|
static DEVICE_ATTR(delete_device, S_IWUSR, NULL, i2c_sysfs_delete_device);
|
|
|
|
static struct attribute *i2c_adapter_attrs[] = {
|
|
&dev_attr_name.attr,
|
|
&dev_attr_new_device.attr,
|
|
&dev_attr_delete_device.attr,
|
|
NULL
|
|
};
|
|
|
|
static struct attribute_group i2c_adapter_attr_group = {
|
|
.attrs = i2c_adapter_attrs,
|
|
};
|
|
|
|
static const struct attribute_group *i2c_adapter_attr_groups[] = {
|
|
&i2c_adapter_attr_group,
|
|
NULL
|
|
};
|
|
|
|
struct device_type i2c_adapter_type = {
|
|
.groups = i2c_adapter_attr_groups,
|
|
.release = i2c_adapter_dev_release,
|
|
};
|
|
EXPORT_SYMBOL_GPL(i2c_adapter_type);
|
|
|
|
/**
|
|
* i2c_verify_adapter - return parameter as i2c_adapter or NULL
|
|
* @dev: device, probably from some driver model iterator
|
|
*
|
|
* When traversing the driver model tree, perhaps using driver model
|
|
* iterators like @device_for_each_child(), you can't assume very much
|
|
* about the nodes you find. Use this function to avoid oopses caused
|
|
* by wrongly treating some non-I2C device as an i2c_adapter.
|
|
*/
|
|
struct i2c_adapter *i2c_verify_adapter(struct device *dev)
|
|
{
|
|
return (dev->type == &i2c_adapter_type)
|
|
? to_i2c_adapter(dev)
|
|
: NULL;
|
|
}
|
|
EXPORT_SYMBOL(i2c_verify_adapter);
|
|
|
|
#ifdef CONFIG_I2C_COMPAT
|
|
static struct class_compat *i2c_adapter_compat_class;
|
|
#endif
|
|
|
|
static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
|
|
{
|
|
struct i2c_devinfo *devinfo;
|
|
|
|
down_read(&__i2c_board_lock);
|
|
list_for_each_entry(devinfo, &__i2c_board_list, list) {
|
|
if (devinfo->busnum == adapter->nr
|
|
&& !i2c_new_device(adapter,
|
|
&devinfo->board_info))
|
|
dev_err(&adapter->dev,
|
|
"Can't create device at 0x%02x\n",
|
|
devinfo->board_info.addr);
|
|
}
|
|
up_read(&__i2c_board_lock);
|
|
}
|
|
|
|
static int i2c_do_add_adapter(struct i2c_driver *driver,
|
|
struct i2c_adapter *adap)
|
|
{
|
|
/* Detect supported devices on that bus, and instantiate them */
|
|
i2c_detect(adap, driver);
|
|
|
|
/* Let legacy drivers scan this bus for matching devices */
|
|
if (driver->attach_adapter) {
|
|
dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
|
|
driver->driver.name);
|
|
dev_warn(&adap->dev, "Please use another way to instantiate "
|
|
"your i2c_client\n");
|
|
/* We ignore the return code; if it fails, too bad */
|
|
driver->attach_adapter(adap);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int __process_new_adapter(struct device_driver *d, void *data)
|
|
{
|
|
return i2c_do_add_adapter(to_i2c_driver(d), data);
|
|
}
|
|
|
|
static int i2c_register_adapter(struct i2c_adapter *adap)
|
|
{
|
|
int res = 0;
|
|
|
|
/* Can't register until after driver model init */
|
|
if (unlikely(WARN_ON(!i2c_bus_type.p))) {
|
|
res = -EAGAIN;
|
|
goto out_list;
|
|
}
|
|
|
|
/* Sanity checks */
|
|
if (unlikely(adap->name[0] == '\0')) {
|
|
pr_err("i2c-core: Attempt to register an adapter with "
|
|
"no name!\n");
|
|
return -EINVAL;
|
|
}
|
|
if (unlikely(!adap->algo)) {
|
|
pr_err("i2c-core: Attempt to register adapter '%s' with "
|
|
"no algo!\n", adap->name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
rt_mutex_init(&adap->bus_lock);
|
|
mutex_init(&adap->userspace_clients_lock);
|
|
INIT_LIST_HEAD(&adap->userspace_clients);
|
|
|
|
/* Set default timeout to 1 second if not already set */
|
|
if (adap->timeout == 0)
|
|
adap->timeout = HZ;
|
|
|
|
dev_set_name(&adap->dev, "i2c-%d", adap->nr);
|
|
adap->dev.bus = &i2c_bus_type;
|
|
adap->dev.type = &i2c_adapter_type;
|
|
res = device_register(&adap->dev);
|
|
if (res)
|
|
goto out_list;
|
|
|
|
dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
|
|
|
|
#ifdef CONFIG_I2C_COMPAT
|
|
res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
|
|
adap->dev.parent);
|
|
if (res)
|
|
dev_warn(&adap->dev,
|
|
"Failed to create compatibility class link\n");
|
|
#endif
|
|
|
|
/* create pre-declared device nodes */
|
|
if (adap->nr < __i2c_first_dynamic_bus_num)
|
|
i2c_scan_static_board_info(adap);
|
|
|
|
/* Notify drivers */
|
|
mutex_lock(&core_lock);
|
|
bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
|
|
mutex_unlock(&core_lock);
|
|
|
|
return 0;
|
|
|
|
out_list:
|
|
mutex_lock(&core_lock);
|
|
idr_remove(&i2c_adapter_idr, adap->nr);
|
|
mutex_unlock(&core_lock);
|
|
return res;
|
|
}
|
|
|
|
/**
|
|
* i2c_add_adapter - declare i2c adapter, use dynamic bus number
|
|
* @adapter: the adapter to add
|
|
* Context: can sleep
|
|
*
|
|
* This routine is used to declare an I2C adapter when its bus number
|
|
* doesn't matter. Examples: for I2C adapters dynamically added by
|
|
* USB links or PCI plugin cards.
|
|
*
|
|
* When this returns zero, a new bus number was allocated and stored
|
|
* in adap->nr, and the specified adapter became available for clients.
|
|
* Otherwise, a negative errno value is returned.
|
|
*/
|
|
int i2c_add_adapter(struct i2c_adapter *adapter)
|
|
{
|
|
int id, res = 0;
|
|
|
|
retry:
|
|
if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
|
|
return -ENOMEM;
|
|
|
|
mutex_lock(&core_lock);
|
|
/* "above" here means "above or equal to", sigh */
|
|
res = idr_get_new_above(&i2c_adapter_idr, adapter,
|
|
__i2c_first_dynamic_bus_num, &id);
|
|
mutex_unlock(&core_lock);
|
|
|
|
if (res < 0) {
|
|
if (res == -EAGAIN)
|
|
goto retry;
|
|
return res;
|
|
}
|
|
|
|
adapter->nr = id;
|
|
return i2c_register_adapter(adapter);
|
|
}
|
|
EXPORT_SYMBOL(i2c_add_adapter);
|
|
|
|
/**
|
|
* i2c_add_numbered_adapter - declare i2c adapter, use static bus number
|
|
* @adap: the adapter to register (with adap->nr initialized)
|
|
* Context: can sleep
|
|
*
|
|
* This routine is used to declare an I2C adapter when its bus number
|
|
* matters. For example, use it for I2C adapters from system-on-chip CPUs,
|
|
* or otherwise built in to the system's mainboard, and where i2c_board_info
|
|
* is used to properly configure I2C devices.
|
|
*
|
|
* If the requested bus number is set to -1, then this function will behave
|
|
* identically to i2c_add_adapter, and will dynamically assign a bus number.
|
|
*
|
|
* If no devices have pre-been declared for this bus, then be sure to
|
|
* register the adapter before any dynamically allocated ones. Otherwise
|
|
* the required bus ID may not be available.
|
|
*
|
|
* When this returns zero, the specified adapter became available for
|
|
* clients using the bus number provided in adap->nr. Also, the table
|
|
* of I2C devices pre-declared using i2c_register_board_info() is scanned,
|
|
* and the appropriate driver model device nodes are created. Otherwise, a
|
|
* negative errno value is returned.
|
|
*/
|
|
int i2c_add_numbered_adapter(struct i2c_adapter *adap)
|
|
{
|
|
int id;
|
|
int status;
|
|
|
|
if (adap->nr == -1) /* -1 means dynamically assign bus id */
|
|
return i2c_add_adapter(adap);
|
|
if (adap->nr & ~MAX_ID_MASK)
|
|
return -EINVAL;
|
|
|
|
retry:
|
|
if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0)
|
|
return -ENOMEM;
|
|
|
|
mutex_lock(&core_lock);
|
|
/* "above" here means "above or equal to", sigh;
|
|
* we need the "equal to" result to force the result
|
|
*/
|
|
status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id);
|
|
if (status == 0 && id != adap->nr) {
|
|
status = -EBUSY;
|
|
idr_remove(&i2c_adapter_idr, id);
|
|
}
|
|
mutex_unlock(&core_lock);
|
|
if (status == -EAGAIN)
|
|
goto retry;
|
|
|
|
if (status == 0)
|
|
status = i2c_register_adapter(adap);
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
|
|
|
|
static int i2c_do_del_adapter(struct i2c_driver *driver,
|
|
struct i2c_adapter *adapter)
|
|
{
|
|
struct i2c_client *client, *_n;
|
|
int res;
|
|
|
|
/* Remove the devices we created ourselves as the result of hardware
|
|
* probing (using a driver's detect method) */
|
|
list_for_each_entry_safe(client, _n, &driver->clients, detected) {
|
|
if (client->adapter == adapter) {
|
|
dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
|
|
client->name, client->addr);
|
|
list_del(&client->detected);
|
|
i2c_unregister_device(client);
|
|
}
|
|
}
|
|
|
|
if (!driver->detach_adapter)
|
|
return 0;
|
|
dev_warn(&adapter->dev, "%s: detach_adapter method is deprecated\n",
|
|
driver->driver.name);
|
|
res = driver->detach_adapter(adapter);
|
|
if (res)
|
|
dev_err(&adapter->dev, "detach_adapter failed (%d) "
|
|
"for driver [%s]\n", res, driver->driver.name);
|
|
return res;
|
|
}
|
|
|
|
static int __unregister_client(struct device *dev, void *dummy)
|
|
{
|
|
struct i2c_client *client = i2c_verify_client(dev);
|
|
if (client && strcmp(client->name, "dummy"))
|
|
i2c_unregister_device(client);
|
|
return 0;
|
|
}
|
|
|
|
static int __unregister_dummy(struct device *dev, void *dummy)
|
|
{
|
|
struct i2c_client *client = i2c_verify_client(dev);
|
|
if (client)
|
|
i2c_unregister_device(client);
|
|
return 0;
|
|
}
|
|
|
|
static int __process_removed_adapter(struct device_driver *d, void *data)
|
|
{
|
|
return i2c_do_del_adapter(to_i2c_driver(d), data);
|
|
}
|
|
|
|
/**
|
|
* i2c_del_adapter - unregister I2C adapter
|
|
* @adap: the adapter being unregistered
|
|
* Context: can sleep
|
|
*
|
|
* This unregisters an I2C adapter which was previously registered
|
|
* by @i2c_add_adapter or @i2c_add_numbered_adapter.
|
|
*/
|
|
int i2c_del_adapter(struct i2c_adapter *adap)
|
|
{
|
|
int res = 0;
|
|
struct i2c_adapter *found;
|
|
struct i2c_client *client, *next;
|
|
|
|
/* First make sure that this adapter was ever added */
|
|
mutex_lock(&core_lock);
|
|
found = idr_find(&i2c_adapter_idr, adap->nr);
|
|
mutex_unlock(&core_lock);
|
|
if (found != adap) {
|
|
pr_debug("i2c-core: attempting to delete unregistered "
|
|
"adapter [%s]\n", adap->name);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Tell drivers about this removal */
|
|
mutex_lock(&core_lock);
|
|
res = bus_for_each_drv(&i2c_bus_type, NULL, adap,
|
|
__process_removed_adapter);
|
|
mutex_unlock(&core_lock);
|
|
if (res)
|
|
return res;
|
|
|
|
/* Remove devices instantiated from sysfs */
|
|
mutex_lock_nested(&adap->userspace_clients_lock,
|
|
i2c_adapter_depth(adap));
|
|
list_for_each_entry_safe(client, next, &adap->userspace_clients,
|
|
detected) {
|
|
dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
|
|
client->addr);
|
|
list_del(&client->detected);
|
|
i2c_unregister_device(client);
|
|
}
|
|
mutex_unlock(&adap->userspace_clients_lock);
|
|
|
|
/* Detach any active clients. This can't fail, thus we do not
|
|
* check the returned value. This is a two-pass process, because
|
|
* we can't remove the dummy devices during the first pass: they
|
|
* could have been instantiated by real devices wishing to clean
|
|
* them up properly, so we give them a chance to do that first. */
|
|
res = device_for_each_child(&adap->dev, NULL, __unregister_client);
|
|
res = device_for_each_child(&adap->dev, NULL, __unregister_dummy);
|
|
|
|
#ifdef CONFIG_I2C_COMPAT
|
|
class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
|
|
adap->dev.parent);
|
|
#endif
|
|
|
|
/* device name is gone after device_unregister */
|
|
dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
|
|
|
|
/* clean up the sysfs representation */
|
|
init_completion(&adap->dev_released);
|
|
device_unregister(&adap->dev);
|
|
|
|
/* wait for sysfs to drop all references */
|
|
wait_for_completion(&adap->dev_released);
|
|
|
|
/* free bus id */
|
|
mutex_lock(&core_lock);
|
|
idr_remove(&i2c_adapter_idr, adap->nr);
|
|
mutex_unlock(&core_lock);
|
|
|
|
/* Clear the device structure in case this adapter is ever going to be
|
|
added again */
|
|
memset(&adap->dev, 0, sizeof(adap->dev));
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(i2c_del_adapter);
|
|
|
|
|
|
/* ------------------------------------------------------------------------- */
|
|
|
|
int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
|
|
{
|
|
int res;
|
|
|
|
mutex_lock(&core_lock);
|
|
res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
|
|
mutex_unlock(&core_lock);
|
|
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_for_each_dev);
|
|
|
|
static int __process_new_driver(struct device *dev, void *data)
|
|
{
|
|
if (dev->type != &i2c_adapter_type)
|
|
return 0;
|
|
return i2c_do_add_adapter(data, to_i2c_adapter(dev));
|
|
}
|
|
|
|
/*
|
|
* An i2c_driver is used with one or more i2c_client (device) nodes to access
|
|
* i2c slave chips, on a bus instance associated with some i2c_adapter.
|
|
*/
|
|
|
|
int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
|
|
{
|
|
int res;
|
|
|
|
/* Can't register until after driver model init */
|
|
if (unlikely(WARN_ON(!i2c_bus_type.p)))
|
|
return -EAGAIN;
|
|
|
|
/* add the driver to the list of i2c drivers in the driver core */
|
|
driver->driver.owner = owner;
|
|
driver->driver.bus = &i2c_bus_type;
|
|
|
|
/* When registration returns, the driver core
|
|
* will have called probe() for all matching-but-unbound devices.
|
|
*/
|
|
res = driver_register(&driver->driver);
|
|
if (res)
|
|
return res;
|
|
|
|
/* Drivers should switch to dev_pm_ops instead. */
|
|
if (driver->suspend)
|
|
pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
|
|
driver->driver.name);
|
|
if (driver->resume)
|
|
pr_warn("i2c-core: driver [%s] using legacy resume method\n",
|
|
driver->driver.name);
|
|
|
|
pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
|
|
|
|
INIT_LIST_HEAD(&driver->clients);
|
|
/* Walk the adapters that are already present */
|
|
i2c_for_each_dev(driver, __process_new_driver);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(i2c_register_driver);
|
|
|
|
static int __process_removed_driver(struct device *dev, void *data)
|
|
{
|
|
if (dev->type != &i2c_adapter_type)
|
|
return 0;
|
|
return i2c_do_del_adapter(data, to_i2c_adapter(dev));
|
|
}
|
|
|
|
/**
|
|
* i2c_del_driver - unregister I2C driver
|
|
* @driver: the driver being unregistered
|
|
* Context: can sleep
|
|
*/
|
|
void i2c_del_driver(struct i2c_driver *driver)
|
|
{
|
|
i2c_for_each_dev(driver, __process_removed_driver);
|
|
|
|
driver_unregister(&driver->driver);
|
|
pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
|
|
}
|
|
EXPORT_SYMBOL(i2c_del_driver);
|
|
|
|
/* ------------------------------------------------------------------------- */
|
|
|
|
/**
|
|
* i2c_use_client - increments the reference count of the i2c client structure
|
|
* @client: the client being referenced
|
|
*
|
|
* Each live reference to a client should be refcounted. The driver model does
|
|
* that automatically as part of driver binding, so that most drivers don't
|
|
* need to do this explicitly: they hold a reference until they're unbound
|
|
* from the device.
|
|
*
|
|
* A pointer to the client with the incremented reference counter is returned.
|
|
*/
|
|
struct i2c_client *i2c_use_client(struct i2c_client *client)
|
|
{
|
|
if (client && get_device(&client->dev))
|
|
return client;
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(i2c_use_client);
|
|
|
|
/**
|
|
* i2c_release_client - release a use of the i2c client structure
|
|
* @client: the client being no longer referenced
|
|
*
|
|
* Must be called when a user of a client is finished with it.
|
|
*/
|
|
void i2c_release_client(struct i2c_client *client)
|
|
{
|
|
if (client)
|
|
put_device(&client->dev);
|
|
}
|
|
EXPORT_SYMBOL(i2c_release_client);
|
|
|
|
struct i2c_cmd_arg {
|
|
unsigned cmd;
|
|
void *arg;
|
|
};
|
|
|
|
static int i2c_cmd(struct device *dev, void *_arg)
|
|
{
|
|
struct i2c_client *client = i2c_verify_client(dev);
|
|
struct i2c_cmd_arg *arg = _arg;
|
|
|
|
if (client && client->driver && client->driver->command)
|
|
client->driver->command(client, arg->cmd, arg->arg);
|
|
return 0;
|
|
}
|
|
|
|
void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
|
|
{
|
|
struct i2c_cmd_arg cmd_arg;
|
|
|
|
cmd_arg.cmd = cmd;
|
|
cmd_arg.arg = arg;
|
|
device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
|
|
}
|
|
EXPORT_SYMBOL(i2c_clients_command);
|
|
|
|
static int __init i2c_init(void)
|
|
{
|
|
int retval;
|
|
|
|
retval = bus_register(&i2c_bus_type);
|
|
if (retval)
|
|
return retval;
|
|
#ifdef CONFIG_I2C_COMPAT
|
|
i2c_adapter_compat_class = class_compat_register("i2c-adapter");
|
|
if (!i2c_adapter_compat_class) {
|
|
retval = -ENOMEM;
|
|
goto bus_err;
|
|
}
|
|
#endif
|
|
retval = i2c_add_driver(&dummy_driver);
|
|
if (retval)
|
|
goto class_err;
|
|
return 0;
|
|
|
|
class_err:
|
|
#ifdef CONFIG_I2C_COMPAT
|
|
class_compat_unregister(i2c_adapter_compat_class);
|
|
bus_err:
|
|
#endif
|
|
bus_unregister(&i2c_bus_type);
|
|
return retval;
|
|
}
|
|
|
|
static void __exit i2c_exit(void)
|
|
{
|
|
i2c_del_driver(&dummy_driver);
|
|
#ifdef CONFIG_I2C_COMPAT
|
|
class_compat_unregister(i2c_adapter_compat_class);
|
|
#endif
|
|
bus_unregister(&i2c_bus_type);
|
|
}
|
|
|
|
/* We must initialize early, because some subsystems register i2c drivers
|
|
* in subsys_initcall() code, but are linked (and initialized) before i2c.
|
|
*/
|
|
postcore_initcall(i2c_init);
|
|
module_exit(i2c_exit);
|
|
|
|
/* ----------------------------------------------------
|
|
* the functional interface to the i2c busses.
|
|
* ----------------------------------------------------
|
|
*/
|
|
|
|
/**
|
|
* __i2c_transfer - unlocked flavor of i2c_transfer
|
|
* @adap: Handle to I2C bus
|
|
* @msgs: One or more messages to execute before STOP is issued to
|
|
* terminate the operation; each message begins with a START.
|
|
* @num: Number of messages to be executed.
|
|
*
|
|
* Returns negative errno, else the number of messages executed.
|
|
*
|
|
* Adapter lock must be held when calling this function. No debug logging
|
|
* takes place. adap->algo->master_xfer existence isn't checked.
|
|
*/
|
|
int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
|
|
{
|
|
unsigned long orig_jiffies;
|
|
int ret, try;
|
|
|
|
/* Retry automatically on arbitration loss */
|
|
orig_jiffies = jiffies;
|
|
for (ret = 0, try = 0; try <= adap->retries; try++) {
|
|
ret = adap->algo->master_xfer(adap, msgs, num);
|
|
if (ret != -EAGAIN)
|
|
break;
|
|
if (time_after(jiffies, orig_jiffies + adap->timeout))
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(__i2c_transfer);
|
|
|
|
/**
|
|
* i2c_transfer - execute a single or combined I2C message
|
|
* @adap: Handle to I2C bus
|
|
* @msgs: One or more messages to execute before STOP is issued to
|
|
* terminate the operation; each message begins with a START.
|
|
* @num: Number of messages to be executed.
|
|
*
|
|
* Returns negative errno, else the number of messages executed.
|
|
*
|
|
* Note that there is no requirement that each message be sent to
|
|
* the same slave address, although that is the most common model.
|
|
*/
|
|
int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
|
|
{
|
|
int ret;
|
|
|
|
/* REVISIT the fault reporting model here is weak:
|
|
*
|
|
* - When we get an error after receiving N bytes from a slave,
|
|
* there is no way to report "N".
|
|
*
|
|
* - When we get a NAK after transmitting N bytes to a slave,
|
|
* there is no way to report "N" ... or to let the master
|
|
* continue executing the rest of this combined message, if
|
|
* that's the appropriate response.
|
|
*
|
|
* - When for example "num" is two and we successfully complete
|
|
* the first message but get an error part way through the
|
|
* second, it's unclear whether that should be reported as
|
|
* one (discarding status on the second message) or errno
|
|
* (discarding status on the first one).
|
|
*/
|
|
|
|
if (adap->algo->master_xfer) {
|
|
#ifdef DEBUG
|
|
for (ret = 0; ret < num; ret++) {
|
|
dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
|
|
"len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
|
|
? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
|
|
(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
|
|
}
|
|
#endif
|
|
|
|
if (in_atomic() || irqs_disabled()) {
|
|
ret = i2c_trylock_adapter(adap);
|
|
if (!ret)
|
|
/* I2C activity is ongoing. */
|
|
return -EAGAIN;
|
|
} else {
|
|
i2c_lock_adapter(adap);
|
|
}
|
|
|
|
ret = __i2c_transfer(adap, msgs, num);
|
|
i2c_unlock_adapter(adap);
|
|
|
|
return ret;
|
|
} else {
|
|
dev_dbg(&adap->dev, "I2C level transfers not supported\n");
|
|
return -EOPNOTSUPP;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(i2c_transfer);
|
|
|
|
/**
|
|
* i2c_master_send - issue a single I2C message in master transmit mode
|
|
* @client: Handle to slave device
|
|
* @buf: Data that will be written to the slave
|
|
* @count: How many bytes to write, must be less than 64k since msg.len is u16
|
|
*
|
|
* Returns negative errno, or else the number of bytes written.
|
|
*/
|
|
int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
|
|
{
|
|
int ret;
|
|
struct i2c_adapter *adap = client->adapter;
|
|
struct i2c_msg msg;
|
|
|
|
msg.addr = client->addr;
|
|
msg.flags = client->flags & I2C_M_TEN;
|
|
msg.len = count;
|
|
msg.buf = (char *)buf;
|
|
|
|
ret = i2c_transfer(adap, &msg, 1);
|
|
|
|
/*
|
|
* If everything went ok (i.e. 1 msg transmitted), return #bytes
|
|
* transmitted, else error code.
|
|
*/
|
|
return (ret == 1) ? count : ret;
|
|
}
|
|
EXPORT_SYMBOL(i2c_master_send);
|
|
|
|
/**
|
|
* i2c_master_recv - issue a single I2C message in master receive mode
|
|
* @client: Handle to slave device
|
|
* @buf: Where to store data read from slave
|
|
* @count: How many bytes to read, must be less than 64k since msg.len is u16
|
|
*
|
|
* Returns negative errno, or else the number of bytes read.
|
|
*/
|
|
int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
|
|
{
|
|
struct i2c_adapter *adap = client->adapter;
|
|
struct i2c_msg msg;
|
|
int ret;
|
|
|
|
msg.addr = client->addr;
|
|
msg.flags = client->flags & I2C_M_TEN;
|
|
msg.flags |= I2C_M_RD;
|
|
msg.len = count;
|
|
msg.buf = buf;
|
|
|
|
ret = i2c_transfer(adap, &msg, 1);
|
|
|
|
/*
|
|
* If everything went ok (i.e. 1 msg received), return #bytes received,
|
|
* else error code.
|
|
*/
|
|
return (ret == 1) ? count : ret;
|
|
}
|
|
EXPORT_SYMBOL(i2c_master_recv);
|
|
|
|
/* ----------------------------------------------------
|
|
* the i2c address scanning function
|
|
* Will not work for 10-bit addresses!
|
|
* ----------------------------------------------------
|
|
*/
|
|
|
|
/*
|
|
* Legacy default probe function, mostly relevant for SMBus. The default
|
|
* probe method is a quick write, but it is known to corrupt the 24RF08
|
|
* EEPROMs due to a state machine bug, and could also irreversibly
|
|
* write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
|
|
* we use a short byte read instead. Also, some bus drivers don't implement
|
|
* quick write, so we fallback to a byte read in that case too.
|
|
* On x86, there is another special case for FSC hardware monitoring chips,
|
|
* which want regular byte reads (address 0x73.) Fortunately, these are the
|
|
* only known chips using this I2C address on PC hardware.
|
|
* Returns 1 if probe succeeded, 0 if not.
|
|
*/
|
|
static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
|
|
{
|
|
int err;
|
|
union i2c_smbus_data dummy;
|
|
|
|
#ifdef CONFIG_X86
|
|
if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
|
|
&& i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
|
|
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
|
|
I2C_SMBUS_BYTE_DATA, &dummy);
|
|
else
|
|
#endif
|
|
if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
|
|
&& i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
|
|
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
|
|
I2C_SMBUS_QUICK, NULL);
|
|
else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
|
|
err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
|
|
I2C_SMBUS_BYTE, &dummy);
|
|
else {
|
|
dev_warn(&adap->dev, "No suitable probing method supported\n");
|
|
err = -EOPNOTSUPP;
|
|
}
|
|
|
|
return err >= 0;
|
|
}
|
|
|
|
static int i2c_detect_address(struct i2c_client *temp_client,
|
|
struct i2c_driver *driver)
|
|
{
|
|
struct i2c_board_info info;
|
|
struct i2c_adapter *adapter = temp_client->adapter;
|
|
int addr = temp_client->addr;
|
|
int err;
|
|
|
|
/* Make sure the address is valid */
|
|
err = i2c_check_addr_validity(addr);
|
|
if (err) {
|
|
dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
|
|
addr);
|
|
return err;
|
|
}
|
|
|
|
/* Skip if already in use */
|
|
if (i2c_check_addr_busy(adapter, addr))
|
|
return 0;
|
|
|
|
/* Make sure there is something at this address */
|
|
if (!i2c_default_probe(adapter, addr))
|
|
return 0;
|
|
|
|
/* Finally call the custom detection function */
|
|
memset(&info, 0, sizeof(struct i2c_board_info));
|
|
info.addr = addr;
|
|
err = driver->detect(temp_client, &info);
|
|
if (err) {
|
|
/* -ENODEV is returned if the detection fails. We catch it
|
|
here as this isn't an error. */
|
|
return err == -ENODEV ? 0 : err;
|
|
}
|
|
|
|
/* Consistency check */
|
|
if (info.type[0] == '\0') {
|
|
dev_err(&adapter->dev, "%s detection function provided "
|
|
"no name for 0x%x\n", driver->driver.name,
|
|
addr);
|
|
} else {
|
|
struct i2c_client *client;
|
|
|
|
/* Detection succeeded, instantiate the device */
|
|
dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
|
|
info.type, info.addr);
|
|
client = i2c_new_device(adapter, &info);
|
|
if (client)
|
|
list_add_tail(&client->detected, &driver->clients);
|
|
else
|
|
dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
|
|
info.type, info.addr);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
|
|
{
|
|
const unsigned short *address_list;
|
|
struct i2c_client *temp_client;
|
|
int i, err = 0;
|
|
int adap_id = i2c_adapter_id(adapter);
|
|
|
|
address_list = driver->address_list;
|
|
if (!driver->detect || !address_list)
|
|
return 0;
|
|
|
|
/* Stop here if the classes do not match */
|
|
if (!(adapter->class & driver->class))
|
|
return 0;
|
|
|
|
/* Set up a temporary client to help detect callback */
|
|
temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
|
|
if (!temp_client)
|
|
return -ENOMEM;
|
|
temp_client->adapter = adapter;
|
|
|
|
for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
|
|
dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
|
|
"addr 0x%02x\n", adap_id, address_list[i]);
|
|
temp_client->addr = address_list[i];
|
|
err = i2c_detect_address(temp_client, driver);
|
|
if (unlikely(err))
|
|
break;
|
|
}
|
|
|
|
kfree(temp_client);
|
|
return err;
|
|
}
|
|
|
|
int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
|
|
{
|
|
return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
|
|
I2C_SMBUS_QUICK, NULL) >= 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
|
|
|
|
struct i2c_client *
|
|
i2c_new_probed_device(struct i2c_adapter *adap,
|
|
struct i2c_board_info *info,
|
|
unsigned short const *addr_list,
|
|
int (*probe)(struct i2c_adapter *, unsigned short addr))
|
|
{
|
|
int i;
|
|
|
|
if (!probe)
|
|
probe = i2c_default_probe;
|
|
|
|
for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
|
|
/* Check address validity */
|
|
if (i2c_check_addr_validity(addr_list[i]) < 0) {
|
|
dev_warn(&adap->dev, "Invalid 7-bit address "
|
|
"0x%02x\n", addr_list[i]);
|
|
continue;
|
|
}
|
|
|
|
/* Check address availability */
|
|
if (i2c_check_addr_busy(adap, addr_list[i])) {
|
|
dev_dbg(&adap->dev, "Address 0x%02x already in "
|
|
"use, not probing\n", addr_list[i]);
|
|
continue;
|
|
}
|
|
|
|
/* Test address responsiveness */
|
|
if (probe(adap, addr_list[i]))
|
|
break;
|
|
}
|
|
|
|
if (addr_list[i] == I2C_CLIENT_END) {
|
|
dev_dbg(&adap->dev, "Probing failed, no device found\n");
|
|
return NULL;
|
|
}
|
|
|
|
info->addr = addr_list[i];
|
|
return i2c_new_device(adap, info);
|
|
}
|
|
EXPORT_SYMBOL_GPL(i2c_new_probed_device);
|
|
|
|
struct i2c_adapter *i2c_get_adapter(int nr)
|
|
{
|
|
struct i2c_adapter *adapter;
|
|
|
|
mutex_lock(&core_lock);
|
|
adapter = idr_find(&i2c_adapter_idr, nr);
|
|
if (adapter && !try_module_get(adapter->owner))
|
|
adapter = NULL;
|
|
|
|
mutex_unlock(&core_lock);
|
|
return adapter;
|
|
}
|
|
EXPORT_SYMBOL(i2c_get_adapter);
|
|
|
|
void i2c_put_adapter(struct i2c_adapter *adap)
|
|
{
|
|
module_put(adap->owner);
|
|
}
|
|
EXPORT_SYMBOL(i2c_put_adapter);
|
|
|
|
/* The SMBus parts */
|
|
|
|
#define POLY (0x1070U << 3)
|
|
static u8 crc8(u16 data)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 8; i++) {
|
|
if (data & 0x8000)
|
|
data = data ^ POLY;
|
|
data = data << 1;
|
|
}
|
|
return (u8)(data >> 8);
|
|
}
|
|
|
|
/* Incremental CRC8 over count bytes in the array pointed to by p */
|
|
static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < count; i++)
|
|
crc = crc8((crc ^ p[i]) << 8);
|
|
return crc;
|
|
}
|
|
|
|
/* Assume a 7-bit address, which is reasonable for SMBus */
|
|
static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
|
|
{
|
|
/* The address will be sent first */
|
|
u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
|
|
pec = i2c_smbus_pec(pec, &addr, 1);
|
|
|
|
/* The data buffer follows */
|
|
return i2c_smbus_pec(pec, msg->buf, msg->len);
|
|
}
|
|
|
|
/* Used for write only transactions */
|
|
static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
|
|
{
|
|
msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
|
|
msg->len++;
|
|
}
|
|
|
|
/* Return <0 on CRC error
|
|
If there was a write before this read (most cases) we need to take the
|
|
partial CRC from the write part into account.
|
|
Note that this function does modify the message (we need to decrease the
|
|
message length to hide the CRC byte from the caller). */
|
|
static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
|
|
{
|
|
u8 rpec = msg->buf[--msg->len];
|
|
cpec = i2c_smbus_msg_pec(cpec, msg);
|
|
|
|
if (rpec != cpec) {
|
|
pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
|
|
rpec, cpec);
|
|
return -EBADMSG;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* i2c_smbus_read_byte - SMBus "receive byte" protocol
|
|
* @client: Handle to slave device
|
|
*
|
|
* This executes the SMBus "receive byte" protocol, returning negative errno
|
|
* else the byte received from the device.
|
|
*/
|
|
s32 i2c_smbus_read_byte(const struct i2c_client *client)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, 0,
|
|
I2C_SMBUS_BYTE, &data);
|
|
return (status < 0) ? status : data.byte;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_byte);
|
|
|
|
/**
|
|
* i2c_smbus_write_byte - SMBus "send byte" protocol
|
|
* @client: Handle to slave device
|
|
* @value: Byte to be sent
|
|
*
|
|
* This executes the SMBus "send byte" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
|
|
{
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_byte);
|
|
|
|
/**
|
|
* i2c_smbus_read_byte_data - SMBus "read byte" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
*
|
|
* This executes the SMBus "read byte" protocol, returning negative errno
|
|
* else a data byte received from the device.
|
|
*/
|
|
s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_BYTE_DATA, &data);
|
|
return (status < 0) ? status : data.byte;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_byte_data);
|
|
|
|
/**
|
|
* i2c_smbus_write_byte_data - SMBus "write byte" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @value: Byte being written
|
|
*
|
|
* This executes the SMBus "write byte" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
|
|
u8 value)
|
|
{
|
|
union i2c_smbus_data data;
|
|
data.byte = value;
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_BYTE_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_byte_data);
|
|
|
|
/**
|
|
* i2c_smbus_read_word_data - SMBus "read word" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
*
|
|
* This executes the SMBus "read word" protocol, returning negative errno
|
|
* else a 16-bit unsigned "word" received from the device.
|
|
*/
|
|
s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_WORD_DATA, &data);
|
|
return (status < 0) ? status : data.word;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_word_data);
|
|
|
|
/**
|
|
* i2c_smbus_write_word_data - SMBus "write word" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @value: 16-bit "word" being written
|
|
*
|
|
* This executes the SMBus "write word" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
|
|
u16 value)
|
|
{
|
|
union i2c_smbus_data data;
|
|
data.word = value;
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_WORD_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_word_data);
|
|
|
|
/**
|
|
* i2c_smbus_process_call - SMBus "process call" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @value: 16-bit "word" being written
|
|
*
|
|
* This executes the SMBus "process call" protocol, returning negative errno
|
|
* else a 16-bit unsigned "word" received from the device.
|
|
*/
|
|
s32 i2c_smbus_process_call(const struct i2c_client *client, u8 command,
|
|
u16 value)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
data.word = value;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_PROC_CALL, &data);
|
|
return (status < 0) ? status : data.word;
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_process_call);
|
|
|
|
/**
|
|
* i2c_smbus_read_block_data - SMBus "block read" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @values: Byte array into which data will be read; big enough to hold
|
|
* the data returned by the slave. SMBus allows at most 32 bytes.
|
|
*
|
|
* This executes the SMBus "block read" protocol, returning negative errno
|
|
* else the number of data bytes in the slave's response.
|
|
*
|
|
* Note that using this function requires that the client's adapter support
|
|
* the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
|
|
* support this; its emulation through I2C messaging relies on a specific
|
|
* mechanism (I2C_M_RECV_LEN) which may not be implemented.
|
|
*/
|
|
s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
|
|
u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_BLOCK_DATA, &data);
|
|
if (status)
|
|
return status;
|
|
|
|
memcpy(values, &data.block[1], data.block[0]);
|
|
return data.block[0];
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_block_data);
|
|
|
|
/**
|
|
* i2c_smbus_write_block_data - SMBus "block write" protocol
|
|
* @client: Handle to slave device
|
|
* @command: Byte interpreted by slave
|
|
* @length: Size of data block; SMBus allows at most 32 bytes
|
|
* @values: Byte array which will be written.
|
|
*
|
|
* This executes the SMBus "block write" protocol, returning negative errno
|
|
* else zero on success.
|
|
*/
|
|
s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
|
|
u8 length, const u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
|
|
if (length > I2C_SMBUS_BLOCK_MAX)
|
|
length = I2C_SMBUS_BLOCK_MAX;
|
|
data.block[0] = length;
|
|
memcpy(&data.block[1], values, length);
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_BLOCK_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_block_data);
|
|
|
|
/* Returns the number of read bytes */
|
|
s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
|
|
u8 length, u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
int status;
|
|
|
|
if (length > I2C_SMBUS_BLOCK_MAX)
|
|
length = I2C_SMBUS_BLOCK_MAX;
|
|
data.block[0] = length;
|
|
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_READ, command,
|
|
I2C_SMBUS_I2C_BLOCK_DATA, &data);
|
|
if (status < 0)
|
|
return status;
|
|
|
|
memcpy(values, &data.block[1], data.block[0]);
|
|
return data.block[0];
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
|
|
|
|
s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
|
|
u8 length, const u8 *values)
|
|
{
|
|
union i2c_smbus_data data;
|
|
|
|
if (length > I2C_SMBUS_BLOCK_MAX)
|
|
length = I2C_SMBUS_BLOCK_MAX;
|
|
data.block[0] = length;
|
|
memcpy(data.block + 1, values, length);
|
|
return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
|
|
I2C_SMBUS_WRITE, command,
|
|
I2C_SMBUS_I2C_BLOCK_DATA, &data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
|
|
|
|
/* Simulate a SMBus command using the i2c protocol
|
|
No checking of parameters is done! */
|
|
static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
|
|
unsigned short flags,
|
|
char read_write, u8 command, int size,
|
|
union i2c_smbus_data *data)
|
|
{
|
|
/* So we need to generate a series of msgs. In the case of writing, we
|
|
need to use only one message; when reading, we need two. We initialize
|
|
most things with sane defaults, to keep the code below somewhat
|
|
simpler. */
|
|
unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
|
|
unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
|
|
int num = read_write == I2C_SMBUS_READ ? 2 : 1;
|
|
struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
|
|
{ addr, flags | I2C_M_RD, 0, msgbuf1 }
|
|
};
|
|
int i;
|
|
u8 partial_pec = 0;
|
|
int status;
|
|
|
|
msgbuf0[0] = command;
|
|
switch (size) {
|
|
case I2C_SMBUS_QUICK:
|
|
msg[0].len = 0;
|
|
/* Special case: The read/write field is used as data */
|
|
msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
|
|
I2C_M_RD : 0);
|
|
num = 1;
|
|
break;
|
|
case I2C_SMBUS_BYTE:
|
|
if (read_write == I2C_SMBUS_READ) {
|
|
/* Special case: only a read! */
|
|
msg[0].flags = I2C_M_RD | flags;
|
|
num = 1;
|
|
}
|
|
break;
|
|
case I2C_SMBUS_BYTE_DATA:
|
|
if (read_write == I2C_SMBUS_READ)
|
|
msg[1].len = 1;
|
|
else {
|
|
msg[0].len = 2;
|
|
msgbuf0[1] = data->byte;
|
|
}
|
|
break;
|
|
case I2C_SMBUS_WORD_DATA:
|
|
if (read_write == I2C_SMBUS_READ)
|
|
msg[1].len = 2;
|
|
else {
|
|
msg[0].len = 3;
|
|
msgbuf0[1] = data->word & 0xff;
|
|
msgbuf0[2] = data->word >> 8;
|
|
}
|
|
break;
|
|
case I2C_SMBUS_PROC_CALL:
|
|
num = 2; /* Special case */
|
|
read_write = I2C_SMBUS_READ;
|
|
msg[0].len = 3;
|
|
msg[1].len = 2;
|
|
msgbuf0[1] = data->word & 0xff;
|
|
msgbuf0[2] = data->word >> 8;
|
|
break;
|
|
case I2C_SMBUS_BLOCK_DATA:
|
|
if (read_write == I2C_SMBUS_READ) {
|
|
msg[1].flags |= I2C_M_RECV_LEN;
|
|
msg[1].len = 1; /* block length will be added by
|
|
the underlying bus driver */
|
|
} else {
|
|
msg[0].len = data->block[0] + 2;
|
|
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
|
|
dev_err(&adapter->dev,
|
|
"Invalid block write size %d\n",
|
|
data->block[0]);
|
|
return -EINVAL;
|
|
}
|
|
for (i = 1; i < msg[0].len; i++)
|
|
msgbuf0[i] = data->block[i-1];
|
|
}
|
|
break;
|
|
case I2C_SMBUS_BLOCK_PROC_CALL:
|
|
num = 2; /* Another special case */
|
|
read_write = I2C_SMBUS_READ;
|
|
if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
|
|
dev_err(&adapter->dev,
|
|
"Invalid block write size %d\n",
|
|
data->block[0]);
|
|
return -EINVAL;
|
|
}
|
|
msg[0].len = data->block[0] + 2;
|
|
for (i = 1; i < msg[0].len; i++)
|
|
msgbuf0[i] = data->block[i-1];
|
|
msg[1].flags |= I2C_M_RECV_LEN;
|
|
msg[1].len = 1; /* block length will be added by
|
|
the underlying bus driver */
|
|
break;
|
|
case I2C_SMBUS_I2C_BLOCK_DATA:
|
|
if (read_write == I2C_SMBUS_READ) {
|
|
msg[1].len = data->block[0];
|
|
} else {
|
|
msg[0].len = data->block[0] + 1;
|
|
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
|
|
dev_err(&adapter->dev,
|
|
"Invalid block write size %d\n",
|
|
data->block[0]);
|
|
return -EINVAL;
|
|
}
|
|
for (i = 1; i <= data->block[0]; i++)
|
|
msgbuf0[i] = data->block[i];
|
|
}
|
|
break;
|
|
default:
|
|
dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
|
|
return -EOPNOTSUPP;
|
|
}
|
|
|
|
i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
|
|
&& size != I2C_SMBUS_I2C_BLOCK_DATA);
|
|
if (i) {
|
|
/* Compute PEC if first message is a write */
|
|
if (!(msg[0].flags & I2C_M_RD)) {
|
|
if (num == 1) /* Write only */
|
|
i2c_smbus_add_pec(&msg[0]);
|
|
else /* Write followed by read */
|
|
partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
|
|
}
|
|
/* Ask for PEC if last message is a read */
|
|
if (msg[num-1].flags & I2C_M_RD)
|
|
msg[num-1].len++;
|
|
}
|
|
|
|
status = i2c_transfer(adapter, msg, num);
|
|
if (status < 0)
|
|
return status;
|
|
|
|
/* Check PEC if last message is a read */
|
|
if (i && (msg[num-1].flags & I2C_M_RD)) {
|
|
status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
|
|
if (status < 0)
|
|
return status;
|
|
}
|
|
|
|
if (read_write == I2C_SMBUS_READ)
|
|
switch (size) {
|
|
case I2C_SMBUS_BYTE:
|
|
data->byte = msgbuf0[0];
|
|
break;
|
|
case I2C_SMBUS_BYTE_DATA:
|
|
data->byte = msgbuf1[0];
|
|
break;
|
|
case I2C_SMBUS_WORD_DATA:
|
|
case I2C_SMBUS_PROC_CALL:
|
|
data->word = msgbuf1[0] | (msgbuf1[1] << 8);
|
|
break;
|
|
case I2C_SMBUS_I2C_BLOCK_DATA:
|
|
for (i = 0; i < data->block[0]; i++)
|
|
data->block[i+1] = msgbuf1[i];
|
|
break;
|
|
case I2C_SMBUS_BLOCK_DATA:
|
|
case I2C_SMBUS_BLOCK_PROC_CALL:
|
|
for (i = 0; i < msgbuf1[0] + 1; i++)
|
|
data->block[i] = msgbuf1[i];
|
|
break;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* i2c_smbus_xfer - execute SMBus protocol operations
|
|
* @adapter: Handle to I2C bus
|
|
* @addr: Address of SMBus slave on that bus
|
|
* @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
|
|
* @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
|
|
* @command: Byte interpreted by slave, for protocols which use such bytes
|
|
* @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
|
|
* @data: Data to be read or written
|
|
*
|
|
* This executes an SMBus protocol operation, and returns a negative
|
|
* errno code else zero on success.
|
|
*/
|
|
s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
|
|
char read_write, u8 command, int protocol,
|
|
union i2c_smbus_data *data)
|
|
{
|
|
unsigned long orig_jiffies;
|
|
int try;
|
|
s32 res;
|
|
|
|
flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
|
|
|
|
if (adapter->algo->smbus_xfer) {
|
|
i2c_lock_adapter(adapter);
|
|
|
|
/* Retry automatically on arbitration loss */
|
|
orig_jiffies = jiffies;
|
|
for (res = 0, try = 0; try <= adapter->retries; try++) {
|
|
res = adapter->algo->smbus_xfer(adapter, addr, flags,
|
|
read_write, command,
|
|
protocol, data);
|
|
if (res != -EAGAIN)
|
|
break;
|
|
if (time_after(jiffies,
|
|
orig_jiffies + adapter->timeout))
|
|
break;
|
|
}
|
|
i2c_unlock_adapter(adapter);
|
|
|
|
if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
|
|
return res;
|
|
/*
|
|
* Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
|
|
* implement native support for the SMBus operation.
|
|
*/
|
|
}
|
|
|
|
return i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
|
|
command, protocol, data);
|
|
}
|
|
EXPORT_SYMBOL(i2c_smbus_xfer);
|
|
|
|
MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
|
|
MODULE_DESCRIPTION("I2C-Bus main module");
|
|
MODULE_LICENSE("GPL");
|