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
  26 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
  27 MODULE_DESCRIPTION("tea6420 driver");
  28 MODULE_LICENSE("GPL");
  29
  30 static int debug;
  31 module_param(debug, int, 0644);
  32
  33 MODULE_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') */
  38 static 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
  82 static const struct v4l2_subdev_audio_ops tea6420_audio_ops = {
  83         .s_routing = tea6420_s_routing,
  84 };
  85
  86 static const struct v4l2_subdev_ops tea6420_ops = {
  87         .audio = &tea6420_audio_ops,
  88 };
  89
  90 static 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
 119 static 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
 127 static const struct i2c_device_id tea6420_id[] = {
 128         { "tea6420", 0 },
 129         { }
 130 };
 131 MODULE_DEVICE_TABLE(i2c, tea6420_id);
 132
 133 static 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
 142 module_i2c_driver(tea6420_driver);