1. 根目录:
2. drivers
3. mfd
4. wm831x-i2c.c

/*
 * wm831x-i2c.c  --  I2C access for Wolfson WM831x PMICs
 *
 * Copyright 2009,2010 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 *  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.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/mfd/core.h>
#include <linux/slab.h>

#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>

static int wm831x_i2c_read_device(struct wm831x *wm831x, unsigned short reg,
				  int bytes, void *dest)
{
	struct i2c_client *i2c = wm831x->control_data;
	int ret;
	u16 r = cpu_to_be16(reg);

	ret = i2c_master_send(i2c, (unsigned char *)&r, 2);
	if (ret < 0)
		return ret;
	if (ret != 2)
		return -EIO;

	ret = i2c_master_recv(i2c, dest, bytes);
	if (ret < 0)
		return ret;
	if (ret != bytes)
		return -EIO;
	return 0;
}

/* Currently we allocate the write buffer on the stack; this is OK for
 * small writes - if we need to do large writes this will need to be
 * revised.
 */
static int wm831x_i2c_write_device(struct wm831x *wm831x, unsigned short reg,
				   int bytes, void *src)
{
	struct i2c_client *i2c = wm831x->control_data;
	struct i2c_msg xfer[2];
	int ret;

	reg = cpu_to_be16(reg);

	xfer[0].addr = i2c->addr;
	xfer[0].flags = 0;
	xfer[0].len = 2;
	xfer[0].buf = (char *)&reg;

	xfer[1].addr = i2c->addr;
	xfer[1].flags = I2C_M_NOSTART;
	xfer[1].len = bytes;
	xfer[1].buf = (char *)src;

	ret = i2c_transfer(i2c->adapter, xfer, 2);
	if (ret < 0)
		return ret;
	if (ret != 2)
		return -EIO;

	return 0;
}

static int wm831x_i2c_probe(struct i2c_client *i2c,
			    const struct i2c_device_id *id)
{
	struct wm831x *wm831x;

	wm831x = kzalloc(sizeof(struct wm831x), GFP_KERNEL);
	if (wm831x == NULL)
		return -ENOMEM;

	i2c_set_clientdata(i2c, wm831x);
	wm831x->dev = &i2c->dev;
	wm831x->control_data = i2c;
	wm831x->read_dev = wm831x_i2c_read_device;
	wm831x->write_dev = wm831x_i2c_write_device;

	return wm831x_device_init(wm831x, id->driver_data, i2c->irq);
}

static int wm831x_i2c_remove(struct i2c_client *i2c)
{
	struct wm831x *wm831x = i2c_get_clientdata(i2c);

	wm831x_device_exit(wm831x);

	return 0;
}

static int wm831x_i2c_suspend(struct device *dev)
{
	struct wm831x *wm831x = dev_get_drvdata(dev);

	return wm831x_device_suspend(wm831x);
}

static const struct i2c_device_id wm831x_i2c_id[] = {
	{ "wm8310", WM8310 },
	{ "wm8311", WM8311 },
	{ "wm8312", WM8312 },
	{ "wm8320", WM8320 },
	{ "wm8321", WM8321 },
	{ "wm8325", WM8325 },
	{ "wm8326", WM8326 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, wm831x_i2c_id);

static const struct dev_pm_ops wm831x_pm_ops = {
	.suspend = wm831x_i2c_suspend,
};

static struct i2c_driver wm831x_i2c_driver = {
	.driver = {
		.name = "wm831x",
		.owner = THIS_MODULE,
		.pm = &wm831x_pm_ops,
	},
	.probe = wm831x_i2c_probe,
	.remove = wm831x_i2c_remove,
	.id_table = wm831x_i2c_id,
};

static int __init wm831x_i2c_init(void)
{
	int ret;

	ret = i2c_add_driver(&wm831x_i2c_driver);
	if (ret != 0)
		pr_err("Failed to register wm831x I2C driver: %d\n", ret);

	return ret;
}
subsys_initcall(wm831x_i2c_init);

static void __exit wm831x_i2c_exit(void)
{
	i2c_del_driver(&wm831x_i2c_driver);
}
module_exit(wm831x_i2c_exit);