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
   6     The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
   7     4 stereo outputs and gain control for each output.
   8     It is cascadable, i.e. it can be found at the adresses 0x98
   9     and 0x9a on the i2c-bus.
  10
  11     For detailed informations download the specifications directly
  12     from SGS Thomson at http://www.st.com
  13
  14     This program is free software; you can redistribute it and/or modify
  15     it under the terms of the GNU General Public License as published by
  16     the Free Software Foundation; either version 2 of the License, or
  17     (at your option) any later version.
  18
  19     This program is distributed in the hope that it will be useful,
  20     but WITHOUT ANY WARRANTY; without even the implied warranty of
  21     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22     GNU General Public License for more details.
  23
  24     You should have received a copy of the GNU General Public License
  25     along with this program; if not, write to the Free Software
  26     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  27   */
  28
  29
  30 #include <linux/module.h>
  31 #include <linux/ioctl.h>
  32 #include <linux/i2c.h>
  33
  34 #include "tea6420.h"
  35
  36 static int debug;               /* insmod parameter */
  37 module_param(debug, int, 0644);
  38 MODULE_PARM_DESC(debug, "Turn on/off device debugging (default:off).");
  39 #define dprintk(args...) \
  40             do { if (debug) { printk("%s: %s()[%d]: ", KBUILD_MODNAME, __func__, __LINE__); printk(args); } } while (0)
  41
  42 /* addresses to scan, found only at 0x4c and/or 0x4d (7-Bit) */
  43 static unsigned short normal_i2c[] = { I2C_ADDR_TEA6420_1, I2C_ADDR_TEA6420_2, I2C_CLIENT_END };
  44
  45 /* magic definition of all other variables and things */
  46 I2C_CLIENT_INSMOD;
  47
  48 static struct i2c_driver driver;
  49 static struct i2c_client client_template;
  50
  51 /* make a connection between the input 'i' and the output 'o'
  52    with gain 'g' for the tea6420-client 'client' (note: i = 6 means 'mute') */
  53 static int tea6420_switch(struct i2c_client *client, int i, int o, int g)
  54 {
  55         u8 byte = 0;
  56         int ret;
  57
  58         dprintk("adr:0x%02x, i:%d, o:%d, g:%d\n", client->addr, i, o, g);
  59
  60         /* check if the parameters are valid */
  61         if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
  62                 return -1;
  63
  64         byte  = ((o - 1) << 5);
  65         byte |= (i - 1);
  66
  67         /* to understand this, have a look at the tea6420-specs (p.5) */
  68         switch (g) {
  69         case 0:
  70                 byte |= (3 << 3);
  71                 break;
  72         case 2:
  73                 byte |= (2 << 3);
  74                 break;
  75         case 4:
  76                 byte |= (1 << 3);
  77                 break;
  78         case 6:
  79                 break;
  80         }
  81
  82         ret = i2c_smbus_write_byte(client, byte);
  83         if (ret) {
  84                 dprintk("i2c_smbus_write_byte() failed, ret:%d\n", ret);
  85                 return -EIO;
  86         }
  87
  88         return 0;
  89 }
  90
  91 /* this function is called by i2c_probe */
  92 static int tea6420_detect(struct i2c_adapter *adapter, int address, int kind)
  93 {
  94         struct i2c_client *client;
  95         int err = 0, i = 0;
  96
  97         /* let's see whether this adapter can support what we need */
  98         if (0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {
  99                 return 0;
 100         }
 101
 102         /* allocate memory for client structure */
 103         client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
 104         if (!client) {
 105                 return -ENOMEM;
 106         }
 107
 108         /* fill client structure */
 109         memcpy(client, &client_template, sizeof(struct i2c_client));
 110         client->addr = address;
 111         client->adapter = adapter;
 112
 113         /* tell the i2c layer a new client has arrived */
 114         if (0 != (err = i2c_attach_client(client))) {
 115                 kfree(client);
 116                 return err;
 117         }
 118
 119         /* set initial values: set "mute"-input to all outputs at gain 0 */
 120         err = 0;
 121         for (i = 1; i < 5; i++) {
 122                 err += tea6420_switch(client, 6, i, 0);
 123         }
 124         if (err) {
 125                 dprintk("could not initialize tea6420\n");
 126                 kfree(client);
 127                 return -ENODEV;
 128         }
 129
 130         printk("tea6420: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
 131
 132         return 0;
 133 }
 134
 135 static int attach(struct i2c_adapter *adapter)
 136 {
 137         /* let's see whether this is a know adapter we can attach to */
 138         if (adapter->id != I2C_HW_SAA7146) {
 139                 dprintk("refusing to probe on unknown adapter [name='%s',id=0x%x]\n", adapter->name, adapter->id);
 140                 return -ENODEV;
 141         }
 142
 143         return i2c_probe(adapter, &addr_data, &tea6420_detect);
 144 }
 145
 146 static int detach(struct i2c_client *client)
 147 {
 148         int ret = i2c_detach_client(client);
 149         kfree(client);
 150         return ret;
 151 }
 152
 153 static int command(struct i2c_client *client, unsigned int cmd, void *arg)
 154 {
 155         struct tea6420_multiplex *a = (struct tea6420_multiplex *)arg;
 156         int result = 0;
 157
 158         switch (cmd) {
 159         case TEA6420_SWITCH:
 160                 result = tea6420_switch(client, a->in, a->out, a->gain);
 161                 break;
 162         default:
 163                 return -ENOIOCTLCMD;
 164         }
 165
 166         return result;
 167 }
 168
 169 static struct i2c_driver driver = {
 170         .driver = {
 171                 .name = "tea6420",
 172         },
 173         .id     = I2C_DRIVERID_TEA6420,
 174         .attach_adapter = attach,
 175         .detach_client  = detach,
 176         .command        = command,
 177 };
 178
 179 static struct i2c_client client_template = {
 180         .name = "tea6420",
 181         .driver = &driver,
 182 };
 183
 184 static int __init this_module_init(void)
 185 {
 186         return i2c_add_driver(&driver);
 187 }
 188
 189 static void __exit this_module_exit(void)
 190 {
 191         i2c_del_driver(&driver);
 192 }
 193
 194 module_init(this_module_init);
 195 module_exit(this_module_exit);
 196
 197 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
 198 MODULE_DESCRIPTION("tea6420 driver");
 199 MODULE_LICENSE("GPL");