tea6420.c

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 /*
    tea6420 - i2c-driver for the tea6420 by SGS Thomson

    Copyright (C) 1998-2003 Michael Hunold <[email protected]>
    Copyright (C) 2008 Hans Verkuil <[email protected]>

    The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
    4 stereo outputs and gain control for each output.
    It is cascadable, i.e. it can be found at the addresses 0x98
    and 0x9a on the i2c-bus.

    For detailed informations download the specifications directly
    from SGS Thomson at http://www.st.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.

    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/ioctl.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <media/v4l2-device.h>
#include <media/v4l2-chip-ident.h>
#include "tea6420.h"

MODULE_AUTHOR("Michael Hunold <[email protected]>");
MODULE_DESCRIPTION("tea6420 driver");
MODULE_LICENSE("GPL");

static int debug;
module_param(debug, int, 0644);

MODULE_PARM_DESC(debug, "Debug level (0-1)");


/* make a connection between the input 'i' and the output 'o'
   with gain 'g' (note: i = 6 means 'mute') */
static int tea6420_s_routing(struct v4l2_subdev *sd,
                 u32 i, u32 o, u32 config)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    int g = (o >> 4) & 0xf;
    u8 byte;
    int ret;

    o &= 0xf;
    v4l2_dbg(1, debug, sd, "i=%d, o=%d, g=%d\n", i, o, g);

    /* check if the parameters are valid */
    if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
        return -EINVAL;

    byte = ((o - 1) << 5);
    byte |= (i - 1);

    /* to understand this, have a look at the tea6420-specs (p.5) */
    switch (g) {
    case 0:
        byte |= (3 << 3);
        break;
    case 2:
        byte |= (2 << 3);
        break;
    case 4:
        byte |= (1 << 3);
        break;
    case 6:
        break;
    }

    ret = i2c_smbus_write_byte(client, byte);
    if (ret) {
        v4l2_dbg(1, debug, sd,
            "i2c_smbus_write_byte() failed, ret:%d\n", ret);
        return -EIO;
    }
    return 0;
}

static int tea6420_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_TEA6420, 0);
}

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

static const struct v4l2_subdev_core_ops tea6420_core_ops = {
    .g_chip_ident = tea6420_g_chip_ident,
};

static const struct v4l2_subdev_audio_ops tea6420_audio_ops = {
    .s_routing = tea6420_s_routing,
};

static const struct v4l2_subdev_ops tea6420_ops = {
    .core = &tea6420_core_ops,
    .audio = &tea6420_audio_ops,
};

static int tea6420_probe(struct i2c_client *client,
              const struct i2c_device_id *id)
{
    struct v4l2_subdev *sd;
    int err, i;

    /* let's see whether this adapter can support what we need */
    if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE))
        return -EIO;

    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, &tea6420_ops);

    /* set initial values: set "mute"-input to all outputs at gain 0 */
    err = 0;
    for (i = 1; i < 5; i++)
        err += tea6420_s_routing(sd, 6, i, 0);
    if (err) {
        v4l_dbg(1, debug, client, "could not initialize tea6420\n");
        return -ENODEV;
    }
    return 0;
}

static int tea6420_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 tea6420_id[] = {
    { "tea6420", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, tea6420_id);

static struct i2c_driver tea6420_driver = {
    .driver = {
        .owner  = THIS_MODULE,
        .name   = "tea6420",
    },
    .probe      = tea6420_probe,
    .remove     = tea6420_remove,
    .id_table   = tea6420_id,
};

module_i2c_driver(tea6420_driver);