// SPDX-License-Identifier: GPL-2.0-or-later
 /*
    tea6415c - i2c-driver for the tea6415c by SGS Thomson

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

    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 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 "tea6415c.h"

MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
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 const struct v4l2_subdev_video_ops tea6415c_video_ops = {
        .s_routing = tea6415c_s_routing,
};

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

static int tea6415c_probe(struct i2c_client *client)
{
        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 = devm_kzalloc(&client->dev, sizeof(*sd), GFP_KERNEL);
        if (sd == NULL)
                return -ENOMEM;
        v4l2_i2c_subdev_init(sd, client, &tea6415c_ops);
        return 0;
}

static void tea6415c_remove(struct i2c_client *client)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(client);

        v4l2_device_unregister_subdev(sd);
}

static const struct i2c_device_id tea6415c_id[] = {
        { "tea6415c" },
        { }
};
MODULE_DEVICE_TABLE(i2c, tea6415c_id);

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

module_i2c_driver(tea6415c_driver);