1. 根目录:
2. drivers
3. media
4. video
5. ths7303.c

/*
 * ths7303- THS7303 Video Amplifier driver
 *
 * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.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 version 2.
 *
 * This program is distributed .as is. WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <linux/videodev2.h>

#include <media/v4l2-device.h>
#include <media/v4l2-subdev.h>
#include <media/v4l2-chip-ident.h>

MODULE_DESCRIPTION("TI THS7303 video amplifier driver");
MODULE_AUTHOR("Chaithrika U S");
MODULE_LICENSE("GPL");

static int debug;
module_param(debug, int, 0644);
MODULE_PARM_DESC(debug, "Debug level 0-1");

/* following function is used to set ths7303 */
static int ths7303_setvalue(struct v4l2_subdev *sd, v4l2_std_id std)
{
	int err = 0;
	u8 val;
	struct i2c_client *client;

	client = v4l2_get_subdevdata(sd);

	if (std & (V4L2_STD_ALL & ~V4L2_STD_SECAM)) {
		val = 0x02;
		v4l2_dbg(1, debug, sd, "setting value for SDTV format\n");
	} else {
		val = 0x00;
		v4l2_dbg(1, debug, sd, "disabling all channels\n");
	}

	err |= i2c_smbus_write_byte_data(client, 0x01, val);
	err |= i2c_smbus_write_byte_data(client, 0x02, val);
	err |= i2c_smbus_write_byte_data(client, 0x03, val);

	if (err)
		v4l2_err(sd, "write failed\n");

	return err;
}

static int ths7303_s_std_output(struct v4l2_subdev *sd, v4l2_std_id norm)
{
	return ths7303_setvalue(sd, norm);
}

static int ths7303_g_chip_ident(struct v4l2_subdev *sd,
				struct v4l2_dbg_chip_ident *chip)
{
	struct i2c_client *client = v4l2_get_subdevdata(sd);

	return v4l2_chip_ident_i2c_client(client, chip, V4L2_IDENT_THS7303, 0);
}

static const struct v4l2_subdev_video_ops ths7303_video_ops = {
	.s_std_output	= ths7303_s_std_output,
};

static const struct v4l2_subdev_core_ops ths7303_core_ops = {
	.g_chip_ident = ths7303_g_chip_ident,
};

static const struct v4l2_subdev_ops ths7303_ops = {
	.core	= &ths7303_core_ops,
	.video 	= &ths7303_video_ops,
};

static int ths7303_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct v4l2_subdev *sd;
	v4l2_std_id std_id = V4L2_STD_NTSC;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -ENODEV;

	v4l_info(client, "chip found @ 0x%x (%s)\n",
			client->addr << 1, client->adapter->name);

	sd = kzalloc(sizeof(struct v4l2_subdev), GFP_KERNEL);
	if (sd == NULL)
		return -ENOMEM;

	v4l2_i2c_subdev_init(sd, client, &ths7303_ops);

	return ths7303_setvalue(sd, std_id);
}

static int ths7303_remove(struct i2c_client *client)
{
	struct v4l2_subdev *sd = i2c_get_clientdata(client);

	v4l2_device_unregister_subdev(sd);
	kfree(sd);

	return 0;
}

static const struct i2c_device_id ths7303_id[] = {
	{"ths7303", 0},
	{},
};

MODULE_DEVICE_TABLE(i2c, ths7303_id);

static struct i2c_driver ths7303_driver = {
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "ths7303",
	},
	.probe		= ths7303_probe,
	.remove		= ths7303_remove,
	.id_table	= ths7303_id,
};

static int __init ths7303_init(void)
{
	return i2c_add_driver(&ths7303_driver);
}

static void __exit ths7303_exit(void)
{
	i2c_del_driver(&ths7303_driver);
}

module_init(ths7303_init);
module_exit(ths7303_exit);