/*
 * 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.
 *
 * 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.
 */


#include <linux/module.h>
#include <linux/types.h>
#include <linux/ioctl.h>
#include <asm/uaccess.h>
#include <linux/i2c.h>
#include <linux/i2c-id.h>
#include <linux/videodev2.h>
#include <media/m52790.h>
#include <media/v4l2-common.h>
#include <media/v4l2-chip-ident.h>
#include <media/v4l2-i2c-drv.h>

MODULE_DESCRIPTION("i2c device driver for m52790 A/V switch");
MODULE_AUTHOR("Hans Verkuil");
MODULE_LICENSE("GPL");


struct m52790_state {
	u16 input;
	u16 output;
};

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

static int m52790_write(struct i2c_client *client)
{
	struct m52790_state *state = i2c_get_clientdata(client);
	u8 sw1 = (state->input | state->output) & 0xff;
	u8 sw2 = (state->input | state->output) >> 8;

	return i2c_smbus_write_byte_data(client, sw1, sw2);
}

static int m52790_command(struct i2c_client *client, unsigned int cmd,
			    void *arg)
{
	struct m52790_state *state = i2c_get_clientdata(client);
	struct v4l2_routing *route = arg;

	/* 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
	   chip takes care of the actual muting so making it part of the
	   output routing seems to be the right thing to do for now. */
	switch (cmd) {
	case VIDIOC_INT_G_AUDIO_ROUTING:
	case VIDIOC_INT_G_VIDEO_ROUTING:
		route->input = state->input;
		route->output = state->output;
		break;

	case VIDIOC_INT_S_AUDIO_ROUTING:
	case VIDIOC_INT_S_VIDEO_ROUTING:
		state->input = route->input;
		state->output = route->output;
		m52790_write(client);
		break;

#ifdef CONFIG_VIDEO_ADV_DEBUG
	case VIDIOC_DBG_G_REGISTER:
	case VIDIOC_DBG_S_REGISTER:
	{
		struct v4l2_register *reg = arg;

		if (!v4l2_chip_match_i2c_client(client,
					reg->match_type, reg->match_chip))
			return -EINVAL;
		if (!capable(CAP_SYS_ADMIN))
			return -EPERM;
		if (reg->reg != 0)
			return -EINVAL;
		if (cmd == VIDIOC_DBG_G_REGISTER)
			reg->val = state->input | state->output;
		else {
			state->input = reg->val & 0x0303;
			state->output = reg->val & ~0x0303;
			m52790_write(client);
		}
		break;
	}
#endif

	case VIDIOC_G_CHIP_IDENT:
		return v4l2_chip_ident_i2c_client(client, arg,
				V4L2_IDENT_M52790, 0);

	case VIDIOC_LOG_STATUS:
		v4l_info(client, "Switch 1: %02x\n",
				(state->input | state->output) & 0xff);
		v4l_info(client, "Switch 2: %02x\n",
				(state->input | state->output) >> 8);
		break;

	default:
		return -EINVAL;
	}
	return 0;
}

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

/* i2c implementation */

static int m52790_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct m52790_state *state;

	/* Check if the adapter supports the needed features */
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA))
		return -EIO;

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

	state = kmalloc(sizeof(struct m52790_state), GFP_KERNEL);
	if (state == NULL)
		return -ENOMEM;

	state->input = M52790_IN_TUNER;
	state->output = M52790_OUT_STEREO;
	i2c_set_clientdata(client, state);
	m52790_write(client);
	return 0;
}

static int m52790_remove(struct i2c_client *client)
{
	kfree(i2c_get_clientdata(client));
	return 0;
}

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

static const struct i2c_device_id m52790_id[] = {
	{ "m52790", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, m52790_id);

static struct v4l2_i2c_driver_data v4l2_i2c_data = {
	.name = "m52790",
	.driverid = I2C_DRIVERID_M52790,
	.command = m52790_command,
	.probe = m52790_probe,
	.remove = m52790_remove,
	.id_table = m52790_id,
};