// SPDX-License-Identifier: GPL-2.0-or-later
 /*
    tea6420 - i2c-driver for the tea6420 by SGS Thomson

    Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
    Copyright (C) 2008 Hans Verkuil <hverkuil@kernel.org>

    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 information download the specifications directly
    from SGS Thomson at http://www.st.com

  */


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

MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
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 const struct v4l2_subdev_audio_ops tea6420_audio_ops = {
        .s_routing = tea6420_s_routing,
};

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

static int tea6420_probe(struct i2c_client *client)
{
        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 = devm_kzalloc(&client->dev, sizeof(*sd), 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 void tea6420_remove(struct i2c_client *client)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(client);

        v4l2_device_unregister_subdev(sd);
}

static const struct i2c_device_id tea6420_id[] = {
        { .name = "tea6420" },
        { }
};
MODULE_DEVICE_TABLE(i2c, tea6420_id);

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

module_i2c_driver(tea6420_driver);