path: root/drivers/i2c/i2c-core.c

/* i2c-core.c - a device driver for the iic-bus interface		     */
/* ------------------------------------------------------------------------- */
/*   Copyright (C) 1995-99 Simon G. Vogl

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.		     */
/* ------------------------------------------------------------------------- */

/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
   All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
   SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
   Jean Delvare <khali@linux-fr.org> */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/idr.h>
#include <linux/seq_file.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/completion.h>
#include <linux/hardirq.h>
#include <linux/irqflags.h>
#include <asm/uaccess.h>
#include <asm/semaphore.h>

#include "i2c-core.h"


static DEFINE_MUTEX(core_lock);
static DEFINE_IDR(i2c_adapter_idr);

#define is_newstyle_driver(d) ((d)->probe || (d)->remove)

/* ------------------------------------------------------------------------- */

static int i2c_device_match(struct device *dev, struct device_driver *drv)
{
	struct i2c_client	*client = to_i2c_client(dev);
	struct i2c_driver	*driver = to_i2c_driver(drv);

	/* make legacy i2c drivers bypass driver model probing entirely;
	 * such drivers scan each i2c adapter/bus themselves.
	 */
	if (!is_newstyle_driver(driver))
		return 0;

	/* new style drivers use the same kind of driver matching policy
	 * as platform devices or SPI:  compare device and driver IDs.
	 */
	return strcmp(client->driver_name, drv->name) == 0;
}

#ifdef	CONFIG_HOTPLUG

/* uevent helps with hotplug: modprobe -q $(MODALIAS) */
static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
	struct i2c_client	*client = to_i2c_client(dev);

	/* by definition, legacy drivers can't hotplug */
	if (dev->driver || !client->driver_name)
		return 0;

	if (add_uevent_var(env, "MODALIAS=%s", client->driver_name))
		return -ENOMEM;
	dev_dbg(dev, "uevent\n");
	return 0;
}

#else
#define i2c_device_uevent	NULL
#endif	/* CONFIG_HOTPLUG */

static int i2c_device_probe(struct device *dev)
{
	struct i2c_client	*client = to_i2c_client(dev);
	struct i2c_driver	*driver = to_i2c_driver(dev->driver);

	if (!driver->probe)
		return -ENODEV;
	client->driver = driver;
	dev_dbg(dev, "probe\n");
	return driver->probe(client);
}

static int i2c_device_remove(struct device *dev)
{
	struct i2c_client	*client = to_i2c_client(dev);
	struct i2c_driver	*driver;
	int			status;

	if (!dev->driver)
		return 0;

	driver = to_i2c_driver(dev->driver);
	if (driver->remove) {
		dev_dbg(dev, "remove\n");
		status = driver->remove(client);
	} else {
		dev->driver = NULL;
		status = 0;
	}
	if (status == 0)
		client->driver = NULL;
	return status;
}

static void i2c_device_shutdown(struct device *dev)
{
	struct i2c_driver *driver;

	if (!dev->driver)
		return;
	driver = to_i2c_driver(dev->driver);
	if (driver->shutdown)
		driver->shutdown(to_i2c_client(dev));
}

static int i2c_device_suspend(struct device * dev, pm_message_t mesg)
{
	struct i2c_driver *driver;

	if (!dev->driver)
		return 0;
	driver = to_i2c_driver(dev->driver);
	if (!driver->suspend)
		return 0;
	return driver->suspend(to_i2c_client(dev), mesg);
}

static int i2c_device_resume(struct device * dev)
{
	struct i2c_driver *driver;

	if (!dev->driver)
		return 0;
	driver = to_i2c_driver(dev->driver);
	if (!driver->resume)
		return 0;
	return driver->resume(to_i2c_client(dev));
}

static void i2c_client_release(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	complete(&client->released);
}

static void i2c_client_dev_release(s