LXR linux/drivers/media/i2c/tea6420.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3    tea6420 - i2c-driver for the tea6420 by SGS Thomson
   4
   5    Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
   6    Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
   7
   8    The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
   9    4 stereo outputs and gain control for each output.
  10    It is cascadable, i.e. it can be found at the addresses 0x98
  11    and 0x9a on the i2c-bus.
  12
  13    For detailed information download the specifications directly
  14    from SGS Thomson at http://www.st.com
  15
  16  */
  17
  18
  19#include <linux/module.h>
  20#include <linux/ioctl.h>
  21#include <linux/slab.h>
  22#include <linux/i2c.h>
  23#include <media/v4l2-device.h>
  24#include "tea6420.h"
  25
  26MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
  27MODULE_DESCRIPTION("tea6420 driver");
  28MODULE_LICENSE("GPL");
  29
  30static int debug;
  31module_param(debug, int, 0644);
  32
  33MODULE_PARM_DESC(debug, "Debug level (0-1)");
  34
  35
  36/* make a connection between the input 'i' and the output 'o'
  37   with gain 'g' (note: i = 6 means 'mute') */
  38static int tea6420_s_routing(struct v4l2_subdev *sd,
  39                             u32 i, u32 o, u32 config)
  40{
  41        struct i2c_client *client = v4l2_get_subdevdata(sd);
  42        int g = (o >> 4) & 0xf;
  43        u8 byte;
  44        int ret;
  45
  46        o &= 0xf;
  47        v4l2_dbg(1, debug, sd, "i=%d, o=%d, g=%d\n", i, o, g);
  48
  49        /* check if the parameters are valid */
  50        if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
  51                return -EINVAL;
  52
  53        byte = ((o - 1) << 5);
  54        byte |= (i - 1);
  55
  56        /* to understand this, have a look at the tea6420-specs (p.5) */
  57        switch (g) {
  58        case 0:
  59                byte |= (3 << 3);
  60                break;
  61        case 2:
  62                byte |= (2 << 3);
  63                break;
  64        case 4:
  65                byte |= (1 << 3);
  66                break;
  67        case 6:
  68                break;
  69        }
  70
  71        ret = i2c_smbus_write_byte(client, byte);
  72        if (ret) {
  73                v4l2_dbg(1, debug, sd,
  74                        "i2c_smbus_write_byte() failed, ret:%d\n", ret);
  75                return -EIO;
  76        }
  77        return 0;
  78}
  79
  80/* ----------------------------------------------------------------------- */
  81
  82static const struct v4l2_subdev_audio_ops tea6420_audio_ops = {
  83        .s_routing = tea6420_s_routing,
  84};
  85
  86static const struct v4l2_subdev_ops tea6420_ops = {
  87        .audio = &tea6420_audio_ops,
  88};
  89
  90static int tea6420_probe(struct i2c_client *client,
  91                          const struct i2c_device_id *id)
  92{
  93        struct v4l2_subdev *sd;
  94        int err, i;
  95
  96        /* let's see whether this adapter can support what we need */
  97        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE))
  98                return -EIO;
  99
 100        v4l_info(client, "chip found @ 0x%x (%s)\n",
 101                        client->addr << 1, client->adapter->name);
 102
 103        sd = devm_kzalloc(&client->dev, sizeof(*sd), GFP_KERNEL);
 104        if (sd == NULL)
 105                return -ENOMEM;
 106        v4l2_i2c_subdev_init(sd, client, &tea6420_ops);
 107
 108        /* set initial values: set "mute"-input to all outputs at gain 0 */
 109        err = 0;
 110        for (i = 1; i < 5; i++)
 111                err += tea6420_s_routing(sd, 6, i, 0);
 112        if (err) {
 113                v4l_dbg(1, debug, client, "could not initialize tea6420\n");
 114                return -ENODEV;
 115        }
 116        return 0;
 117}
 118
 119static int tea6420_remove(struct i2c_client *client)
 120{
 121        struct v4l2_subdev *sd = i2c_get_clientdata(client);
 122
 123        v4l2_device_unregister_subdev(sd);
 124        return 0;
 125}
 126
 127static const struct i2c_device_id tea6420_id[] = {
 128        { "tea6420", 0 },
 129        { }
 130};
 131MODULE_DEVICE_TABLE(i2c, tea6420_id);
 132
 133static struct i2c_driver tea6420_driver = {
 134        .driver = {
 135                .name   = "tea6420",
 136        },
 137        .probe          = tea6420_probe,
 138        .remove         = tea6420_remove,
 139        .id_table       = tea6420_id,
 140};
 141
 142module_i2c_driver(tea6420_driver);
 143