linux-imx

/*

 * m52790 i2c ivtv driver.

 * Copyright (C) 2007  Hans Verkuil

 *

 * A/V source switching Mitsubishi M52790SP/FP

 *

 * 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.

 */

​

​

#include <linux/module.h>

#include <linux/types.h>

#include <linux/slab.h>

#include <linux/ioctl.h>

#include <linux/uaccess.h>

#include <linux/i2c.h>

#include <linux/videodev2.h>

#include <media/i2c/m52790.h>

#include <media/v4l2-device.h>

​

MODULE_DESCRIPTION("i2c device driver for m52790 A/V switch");

MODULE_AUTHOR("Hans Verkuil");

MODULE_LICENSE("GPL");

​

​

struct m52790_state {

    struct v4l2_subdev sd;

    u16 input;

    u16 output;

};

​

static inline struct m52790_state *to_state(struct v4l2_subdev *sd)

{

    return container_of(sd, struct m52790_state, sd);

}

​

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

​

static int m52790_write(struct v4l2_subdev *sd)

{

    struct m52790_state *state = to_state(sd);

    struct i2c_client *client = v4l2_get_subdevdata(sd);

​

    u8 sw1 = (state->input | state->output) & 0xff;

    u8 sw2 = (state->input | state->output) >> 8;

​

    return i2c_smbus_write_byte_data(client, sw1, sw2);

}

​

/* Note: audio and video are linked and cannot be switched separately.

   So audio and video routing commands are identical for this chip.

   In theory the video amplifier and audio modes could be handled

   separately for the output, but that seems to be overkill right now.

   The same holds for implementing an audio mute control, this is now

   part of the audio output routing. The normal case is that another