drivers/media/video/tea6420.c

   1  /*
   2     tea6420 - i2c-driver for the tea6420 by SGS Thomson
   3
   4     Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
   5     Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
   6
   7     The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
   8     4 stereo outputs and gain control for each output.
   9     It is cascadable, i.e. it can be found at the adresses 0x98
  10     and 0x9a on the i2c-bus.
  11
  12     For detailed informations download the specifications directly
  13     from SGS Thomson at http://www.st.com
  14
  15     This program is free software; you can redistribute it and/or modify
  16     it under the terms of the GNU General Public License as published by
  17     the Free Software Foundation; either version 2 of the License, or
  18     (at your option) any later version.
  19
  20     This program is distributed in the hope that it will be useful,
  21     but WITHOUT ANY WARRANTY; without even the implied warranty of
  22     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23     GNU General Public License for more details.
  24
  25     You should have received a copy of the GNU General Public License
  26     along with this program; if not, write to the Free Software
  27     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  28   */
  29
  30
  31 #include <linux/module.h>
  32 #include <linux/ioctl.h>
  33 #include <linux/i2c.h>
  34 #include <media/v4l2-common.h>
  35 #include <media/v4l2-i2c-drv-legacy.h>
  36 #include "tea6420.h"
  37
  38 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
  39 MODULE_DESCRIPTION("tea6420 driver");
  40 MODULE_LICENSE("GPL");
  41
  42 static int debug;
  43 module_param(debug, int, 0644);
  44
  45 MODULE_PARM_DESC(debug, "Debug level (0-1)");
  46
  47 /* addresses to scan, found only at 0x4c and/or 0x4d (7-Bit) */
  48 static unsigned short normal_i2c[] = { I2C_ADDR_TEA6420_1, I2C_ADDR_TEA6420_2, I2C_CLIENT_END };
  49
  50 /* magic definition of all other variables and things */
  51 I2C_CLIENT_INSMOD;
  52
  53 /* make a connection between the input 'i' and the output 'o'
  54    with gain 'g' for the tea6420-client 'client' (note: i = 6 means 'mute') */
  55 static int tea6420_switch(struct i2c_client *client, int i, int o, int g)
  56 {
  57         u8 byte;
  58         int ret;
  59
  60         v4l_dbg(1, debug, client, "i=%d, o=%d, g=%d\n", i, o, g);
  61
  62         /* check if the parameters are valid */
  63         if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
  64                 return -1;
  65
  66         byte = ((o - 1) << 5);
  67         byte |= (i - 1);
  68
  69         /* to understand this, have a look at the tea6420-specs (p.5) */
  70         switch (g) {
  71         case 0:
  72                 byte |= (3 << 3);
  73                 break;
  74         case 2:
  75                 byte |= (2 << 3);
  76                 break;
  77         case 4:
  78                 byte |= (1 << 3);
  79                 break;
  80         case 6:
  81                 break;
  82         }
  83
  84         ret = i2c_smbus_write_byte(client, byte);
  85         if (ret) {
  86                 v4l_dbg(1, debug, client,
  87                         "i2c_smbus_write_byte() failed, ret:%d\n", ret);
  88                 return -EIO;
  89         }
  90         return 0;
  91 }
  92
  93 static int tea6420_command(struct i2c_client *client, unsigned cmd, void *arg)
  94 {
  95         struct tea6420_multiplex *a = (struct tea6420_multiplex *)arg;
  96         int result = 0;
  97
  98         switch (cmd) {
  99         case TEA6420_SWITCH:
 100                 result = tea6420_switch(client, a->in, a->out, a->gain);
 101                 break;
 102         default:
 103                 return -ENOIOCTLCMD;
 104         }
 105
 106         return result;
 107 }
 108
 109 /* this function is called by i2c_probe */
 110 static int tea6420_probe(struct i2c_client *client,
 111                           const struct i2c_device_id *id)
 112 {
 113         int err, i;
 114
 115         /* let's see whether this adapter can support what we need */
 116         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE))
 117                 return -EIO;
 118
 119         v4l_info(client, "chip found @ 0x%x (%s)\n",
 120                         client->addr << 1, client->adapter->name);
 121
 122         /* set initial values: set "mute"-input to all outputs at gain 0 */
 123         err = 0;
 124         for (i = 1; i < 5; i++) {
 125                 err += tea6420_switch(client, 6, i, 0);
 126         }
 127         if (err) {
 128                 v4l_dbg(1, debug, client, "could not initialize tea6420\n");
 129                 kfree(client);
 130                 return -ENODEV;
 131         }
 132         return 0;
 133 }
 134
 135 static int tea6420_legacy_probe(struct i2c_adapter *adapter)
 136 {
 137         /* Let's see whether this is a known adapter we can attach to.
 138            Prevents conflicts with tvaudio.c. */
 139         return adapter->id == I2C_HW_SAA7146;
 140 }
 141
 142 static const struct i2c_device_id tea6420_id[] = {
 143         { "tea6420", 0 },
 144         { }
 145 };
 146 MODULE_DEVICE_TABLE(i2c, tea6420_id);
 147
 148 static struct v4l2_i2c_driver_data v4l2_i2c_data = {
 149         .name = "tea6420",
 150         .driverid = I2C_DRIVERID_TEA6420,
 151         .command = tea6420_command,
 152         .probe = tea6420_probe,
 153         .legacy_probe = tea6420_legacy_probe,
 154         .id_table = tea6420_id,
 155 };