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 #include <linux/module.h>
  30 #include <linux/ioctl.h>
  31 #include <linux/i2c.h>
  32
  33 #include "tea6420.h"
  34
  35 static int debug = 0;           /* insmod parameter */
  36 module_param(debug, int, 0644);
  37 MODULE_PARM_DESC(debug, "Turn on/off device debugging (default:off).");
  38 #define dprintk(args...) \
  39             do { if (debug) { printk("%s: %s()[%d]: ",__stringify(KBUILD_MODNAME), __FUNCTION__, __LINE__); printk(args); } } while (0)
  40
  41 /* addresses to scan, found only at 0x4c and/or 0x4d (7-Bit) */
  42 static unsigned short normal_i2c[] = { I2C_TEA6420_1, I2C_TEA6420_2, I2C_CLIENT_END };
  43 static unsigned short normal_i2c_range[] = { 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 paramters 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 = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
 104         if (0 == client) {
 105                 return -ENOMEM;
 106         }
 107         memset(client, 0x0, sizeof(struct i2c_client));
 108
 109         /* fill client structure */
 110         memcpy(client, &client_template, sizeof(struct i2c_client));
 111         client->addr = address;
 112         client->adapter = adapter;
 113
 114         /* tell the i2c layer a new client has arrived */
 115         if (0 != (err = i2c_attach_client(client))) {
 116                 kfree(client);
 117                 return err;
 118         }
 119
 120         /* set initial values: set "mute"-input to all outputs at gain 0 */
 121         err = 0;
 122         for (i = 1; i < 5; i++) {
 123                 err += tea6420_switch(client, 6, i, 0);
 124         }
 125         if (err) {
 126                 dprintk("could not initialize tea6420\n");
 127                 kfree(client);
 128                 return -ENODEV;
 129         }
 130
 131         printk("tea6420: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
 132
 133         return 0;
 134 }
 135
 136 static int attach(struct i2c_adapter *adapter)
 137 {
 138         /* let's see whether this is a know adapter we can attach to */
 139         if (adapter->id != I2C_ALGO_SAA7146) {
 140                 dprintk("refusing to probe on unknown adapter [name='%s',id=0x%x]\n", adapter->name, adapter->id);
 141                 return -ENODEV;
 142         }
 143
 144         return i2c_probe(adapter, &addr_data, &tea6420_detect);
 145 }
 146
 147 static int detach(struct i2c_client *client)
 148 {
 149         int ret = i2c_detach_client(client);
 150         kfree(client);
 151         return ret;
 152 }
 153
 154 static int command(struct i2c_client *client, unsigned int cmd, void *arg)
 155 {
 156         struct tea6420_multiplex *a = (struct tea6420_multiplex *)arg;
 157         int result = 0;
 158
 159         switch (cmd) {
 160         case TEA6420_SWITCH:
 161                 result = tea6420_switch(client, a->in, a->out, a->gain);
 162                 break;
 163         default:
 164                 return -ENOIOCTLCMD;
 165         }
 166
 167         return result;
 168 }
 169
 170 static struct i2c_driver driver = {
 171         .owner  = THIS_MODULE,
 172         .name   = "tea6420",
 173         .id     = I2C_DRIVERID_TEA6420,
 174         .flags  = I2C_DF_NOTIFY,
 175         .attach_adapter = attach,
 176         .detach_client  = detach,
 177         .command        = command,
 178 };
 179
 180 static struct i2c_client client_template = {
 181         I2C_DEVNAME("tea6420"),
 182         .driver = &driver,
 183 };
 184
 185 static int __init this_module_init(void)
 186 {
 187         return i2c_add_driver(&driver);
 188 }
 189
 190 static void __exit this_module_exit(void)
 191 {
 192         i2c_del_driver(&driver);
 193 }
 194
 195 module_init(this_module_init);
 196 module_exit(this_module_exit);
 197
 198 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
 199 MODULE_DESCRIPTION("tea6420 driver");
 200 MODULE_LICENSE("GPL");