drivers/media/video/tea6420.c

   1  /*
   2     tea6420.o - 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 #include <linux/version.h>
  30 #include <linux/module.h>
  31 #include <linux/kernel.h>
  32 #include <linux/poll.h>
  33 #include <linux/slab.h>
  34 #include <linux/i2c.h>
  35 #include <linux/init.h>
  36
  37 #include "tea6420.h"
  38
  39 static int debug = 0;   /* insmod parameter */
  40 MODULE_PARM(debug,"i");
  41 #define dprintk if (debug) printk
  42
  43 /* addresses to scan, found only at 0x4c and/or 0x4d (7-Bit) */
  44 static unsigned short normal_i2c[] = {I2C_TEA6420_1, I2C_TEA6420_2, I2C_CLIENT_END};
  45 static unsigned short normal_i2c_range[] = {I2C_CLIENT_END};
  46
  47 /* magic definition of all other variables and things */
  48 I2C_CLIENT_INSMOD;
  49
  50 static struct i2c_driver driver;
  51
  52 /* unique ID allocation */
  53 static int tea6420_id = 0;
  54
  55 /* make a connection between the input 'i' and the output 'o'
  56    with gain 'g' for the tea6420-client 'client' (note: i = 6 means 'mute') */
  57 static int tea6420_switch(struct i2c_client *client, int i, int o, int g)
  58 {
  59         u8      byte = 0;
  60
  61         int     result = 0;
  62
  63         dprintk("tea6420.o: tea6420_switch: adr:0x%02x, i:%d, o:%d, g:%d\n",client->addr,i,o,g);
  64
  65         /* check if the paramters are valid */
  66         if ( i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g%2 != 0 )
  67                 return -1;
  68
  69         byte  = ((o-1)<<5);
  70         byte |=  (i-1);
  71
  72         /* to understand this, have a look at the tea6420-specs (p.5) */
  73         switch(g) {
  74                 case 0:
  75                         byte |= (3<<3);
  76                         break;
  77                 case 2:
  78                         byte |= (2<<3);
  79                         break;
  80                 case 4:
  81                         byte |= (1<<3);
  82                         break;
  83                 case 6:
  84                         break;
  85         }
  86
  87         /* fixme?: 1 != ... => 0 != */
  88         if ( 0 != (result = i2c_smbus_write_byte(client,byte))) {
  89                 printk("tea6402:%d\n",result);
  90                 dprintk(KERN_ERR "tea6420.o: could not switch, result:%d\n",result);
  91                 return -EFAULT;
  92         }
  93
  94         return 0;
  95 }
  96
  97 /* this function is called by i2c_probe */
  98 static int tea6420_detect(struct i2c_adapter *adapter, int address, int kind)
  99 {
 100         struct  i2c_client *client;
 101         int err = 0, i = 0;
 102
 103         /* let's see whether this adapter can support what we need */
 104         if ( 0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {
 105                 return 0;
 106         }
 107
 108         /* allocate memory for client structure */
 109         client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
 110         if (0 == client) {
 111                 return -ENOMEM;
 112         }
 113         memset(client, 0x0, sizeof(struct i2c_client));
 114
 115         /* fill client structure */
 116         sprintf(client->name,"tea6420 (0x%02x)", address);
 117         client->id = tea6420_id++;
 118         client->flags = 0;
 119         client->addr = address;
 120         client->adapter = adapter;
 121         client->driver = &driver;
 122         i2c_set_clientdata(client, NULL);
 123
 124         /* tell the i2c layer a new client has arrived */
 125         if (0 != (err = i2c_attach_client(client))) {
 126                 kfree(client);
 127                 return err;
 128         }
 129
 130         /* set initial values: set "mute"-input to all outputs at gain 0 */
 131         err = 0;
 132         for(i = 1; i < 5; i++) {
 133                 err += tea6420_switch(client, 6, i, 0);
 134         }
 135         if( 0 != err) {
 136                 printk("tea6420.o: could not initialize chipset. continuing anyway.\n");
 137         }
 138
 139         printk("tea6420.o: detected @ 0x%02x on adapter %s\n",2*address,&client->adapter->name[0]);
 140
 141         return 0;
 142 }
 143
 144 static int tea6420_attach(struct i2c_adapter *adapter)
 145 {
 146         /* let's see whether this is a know adapter we can attach to */
 147         if( adapter->id != I2C_ALGO_SAA7146 ) {
 148                 dprintk("tea6420.o: refusing to probe on unknown adapter [name='%s',id=0x%x]\n",adapter->name,adapter->id);
 149                 return -ENODEV;
 150         }
 151
 152         return i2c_probe(adapter,&addr_data,&tea6420_detect);
 153 }
 154
 155 static int tea6420_detach(struct i2c_client *client)
 156 {
 157         int err = 0;
 158
 159         if ( 0 != (err = i2c_detach_client(client))) {
 160                 printk("tea6420.o: Client deregistration failed, client not detached.\n");
 161                 return err;
 162         }
 163
 164         kfree(client);
 165
 166         return 0;
 167 }
 168
 169 static int tea6420_command(struct i2c_client *client, unsigned int cmd, void* arg)
 170 {
 171         struct tea6420_multiplex *a = (struct tea6420_multiplex*)arg;
 172         int result = 0;
 173
 174         switch (cmd) {
 175                 case TEA6420_SWITCH: {
 176                         result = tea6420_switch(client,a->in,a->out,a->gain);
 177                         break;
 178                 }
 179                 default: {
 180                         return -ENOIOCTLCMD;
 181                 }
 182         }
 183
 184         if ( 0 != result )
 185                 return result;
 186
 187         return 0;
 188 }
 189
 190 static struct i2c_driver driver = {
 191         .owner          = THIS_MODULE,
 192         .name           = "tea6420 driver",
 193         .id             = I2C_DRIVERID_TEA6420,
 194         .flags          = I2C_DF_NOTIFY,
 195         .attach_adapter = tea6420_attach,
 196         .detach_client  = tea6420_detach,
 197         .command        = tea6420_command,
 198 };
 199
 200 static int __init tea6420_init_module(void)
 201 {
 202         return i2c_add_driver(&driver);
 203 }
 204
 205 static void __exit tea6420_cleanup_module(void)
 206 {
 207         i2c_del_driver(&driver);
 208 }
 209
 210 module_init(tea6420_init_module);
 211 module_exit(tea6420_cleanup_module);
 212
 213 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
 214 MODULE_DESCRIPTION("tea6420 driver");
 215 MODULE_LICENSE("GPL");