tea6415c.c

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 /*
    tea6415c - i2c-driver for the tea6415c by SGS Thomson

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

    The tea6415c is a bus controlled video-matrix-switch
    with 8 inputs and 6 outputs.
    It is cascadable, i.e. it can be found at the addresses
    0x86 and 0x06 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 vs 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 Mvss 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 "tea6415c.h"

MODULE_AUTHOR("Michael Hunold <[email protected]>");
MODULE_DESCRIPTION("tea6415c driver");
MODULE_LICENSE("GPL");

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

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


/* makes a connection between the input-pin 'i' and the output-pin 'o' */
static int tea6415c_s_routing(struct v4l2_subdev *sd,
                  u32 i, u32 o, u32 config)
{
    struct i2c_client *client = v4l2_get_subdevdata(sd);
    u8 byte = 0;
    int ret;

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

    /* check if the pins are valid */
    if (0 == ((1 == i ||  3 == i ||  5 == i ||  6 == i ||  8 == i || 10 == i || 20 == i || 11 == i)
          && (18 == o || 17 == o || 16 == o || 15 == o || 14 == o || 13 == o)))
        return -EINVAL;

    /* to understand this, have a look at the tea6415c-specs (p.5) */
    switch (o) {
    case 18:
        byte = 0x00;
        break;
    case 14:
        byte = 0x20;
        break;
    case 16:
        byte = 0x10;
        break;
    case 17:
        byte = 0x08;
        break;
    case 15:
        byte = 0x18;
        break;
    case 13:
        byte = 0x28;
        break;
    }

    switch (i) {
    case 5:
        byte |= 0x00;
        break;
    case 8:
        byte |= 0x04;
        break;
    case 3:
        byte |= 0x02;
        break;
    case 20:
        byte |= 0x06;
        break;
    case 6:
        byte |= 0x01;
        break;
    case 10:
        byte |= 0x05;
        break;
    case 1:
        byte |= 0x03;
        break;
    case 11:
        byte |= 0x07;
        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 ret;
}

static int tea6415c_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_TEA6415C, 0);
}

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

static const struct v4l2_subdev_core_ops tea6415c_core_ops = {
    .g_chip_ident = tea6415c_g_chip_ident,
};

static const struct v4l2_subdev_video_ops tea6415c_video_ops = {
    .s_routing = tea6415c_s_routing,
};

static const struct v4l2_subdev_ops tea6415c_ops = {
    .core = &tea6415c_core_ops,
    .video = &tea6415c_video_ops,
};

static int tea6415c_probe(struct i2c_client *client,
              const struct i2c_device_id *id)
{
    struct v4l2_subdev *sd;

    /* 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, &tea6415c_ops);
    return 0;
}

static int tea6415c_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 tea6415c_id[] = {
    { "tea6415c", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, tea6415c_id);

static struct i2c_driver tea6415c_driver = {
    .driver = {
        .owner  = THIS_MODULE,
        .name   = "tea6415c",
    },
    .probe      = tea6415c_probe,
    .remove     = tea6415c_remove,
    .id_table   = tea6415c_id,
};

module_i2c_driver(tea6415c_driver);