// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Cirrus Logic cs3308 8-Channel Analog Volume Control
 *
 * Copyright (C) 2010 Devin Heitmueller <dheitmueller@kernellabs.com>
 * Copyright (C) 2012 Steven Toth <stoth@kernellabs.com>
 *
 * Derived from cs5345.c Copyright (C) 2007 Hans Verkuil
 */


#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/videodev2.h>
#include <media/v4l2-device.h>

MODULE_DESCRIPTION("i2c device driver for cs3308 8-channel volume control");
MODULE_AUTHOR("Devin Heitmueller");
MODULE_LICENSE("GPL");

static inline int cs3308_write(struct v4l2_subdev *sd, u8 reg, u8 value)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        return i2c_smbus_write_byte_data(client, reg, value);
}

static inline int cs3308_read(struct v4l2_subdev *sd, u8 reg)
{
        struct i2c_client *client = v4l2_get_subdevdata(sd);

        return i2c_smbus_read_byte_data(client, reg);
}

#ifdef CONFIG_VIDEO_ADV_DEBUG
static int cs3308_g_register(struct v4l2_subdev *sd, struct v4l2_dbg_register *reg)
{
        reg->val = cs3308_read(sd, reg->reg & 0xffff);
        reg->size = 1;
        return 0;
}

static int cs3308_s_register(struct v4l2_subdev *sd, const struct v4l2_dbg_register *reg)
{
        cs3308_write(sd, reg->reg & 0xffff, reg->val & 0xff);
        return 0;
}
#endif

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

static const struct v4l2_subdev_core_ops cs3308_core_ops = {
#ifdef CONFIG_VIDEO_ADV_DEBUG
        .g_register = cs3308_g_register,
        .s_register = cs3308_s_register,
#endif
};

static const struct v4l2_subdev_ops cs3308_ops = {
        .core = &cs3308_core_ops,
};

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

static int cs3308_probe(struct i2c_client *client)
{
        struct v4l2_subdev *sd;
        unsigned i;

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

        if ((i2c_smbus_read_byte_data(client, 0x1c) & 0xf0) != 0xe0)
                return -ENODEV;

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

        sd = kzalloc_obj(struct v4l2_subdev);
        if (sd == NULL)
                return -ENOMEM;

        v4l2_i2c_subdev_init(sd, client, &cs3308_ops);

        /* Set some reasonable defaults */
        cs3308_write(sd, 0x0d, 0x00); /* Power up all channels */
        cs3308_write(sd, 0x0e, 0x00); /* Master Power */
        cs3308_write(sd, 0x0b, 0x00); /* Device Configuration */
        /* Set volume for each channel */
        for (i = 1; i <= 8; i++)
                cs3308_write(sd, i, 0xd2);
        cs3308_write(sd, 0x0a, 0x00); /* Unmute all channels */
        return 0;
}

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

static void cs3308_remove(struct i2c_client *client)
{
        struct v4l2_subdev *sd = i2c_get_clientdata(client);

        v4l2_device_unregister_subdev(sd);
        kfree(sd);
}

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

static const struct i2c_device_id cs3308_id[] = {
        { "cs3308" },
        { }
};
MODULE_DEVICE_TABLE(i2c, cs3308_id);

static struct i2c_driver cs3308_driver = {
        .driver = {
                .name   = "cs3308",
        },
        .probe          = cs3308_probe,
        .remove         = cs3308_remove,
        .id_table       = cs3308_id,
};

module_i2c_driver(cs3308_driver);