drivers/media/video/tea6415c.c

   1  /*
   2     tea6415c - i2c-driver for the tea6415c by SGS Thomson
   3
   4     Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
   5
   6     The tea6415c is a bus controlled video-matrix-switch
   7     with 8 inputs and 6 outputs.
   8     It is cascadable, i.e. it can be found at the addresses
   9     0x86 and 0x06 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 vs 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 Mvss 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 "tea6415c.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]: ", KBUILD_MODNAME, __FUNCTION__, __LINE__); printk(args); } } while (0)
  40
  41 #define TEA6415C_NUM_INPUTS     8
  42 #define TEA6415C_NUM_OUTPUTS    6
  43
  44 /* addresses to scan, found only at 0x03 and/or 0x43 (7-bit) */
  45 static unsigned short normal_i2c[] = { I2C_TEA6415C_1, I2C_TEA6415C_2, 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 static struct i2c_client client_template;
  52
  53 /* this function is called by i2c_probe */
  54 static int detect(struct i2c_adapter *adapter, int address, int kind)
  55 {
  56         struct i2c_client *client = NULL;
  57         int err = 0;
  58
  59         /* let's see whether this adapter can support what we need */
  60         if (0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {
  61                 return 0;
  62         }
  63
  64         /* allocate memory for client structure */
  65         client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
  66         if (0 == client) {
  67                 return -ENOMEM;
  68         }
  69
  70         /* fill client structure */
  71         memcpy(client, &client_template, sizeof(struct i2c_client));
  72         client->addr = address;
  73         client->adapter = adapter;
  74
  75         /* tell the i2c layer a new client has arrived */
  76         if (0 != (err = i2c_attach_client(client))) {
  77                 kfree(client);
  78                 return err;
  79         }
  80
  81         printk("tea6415c: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
  82
  83         return 0;
  84 }
  85
  86 static int attach(struct i2c_adapter *adapter)
  87 {
  88         /* let's see whether this is a know adapter we can attach to */
  89         if (adapter->id != I2C_HW_SAA7146) {
  90                 dprintk("refusing to probe on unknown adapter [name='%s',id=0x%x]\n", adapter->name, adapter->id);
  91                 return -ENODEV;
  92         }
  93
  94         return i2c_probe(adapter, &addr_data, &detect);
  95 }
  96
  97 static int detach(struct i2c_client *client)
  98 {
  99         int ret = i2c_detach_client(client);
 100         kfree(client);
 101         return ret;
 102 }
 103
 104 /* makes a connection between the input-pin 'i' and the output-pin 'o'
 105    for the tea6415c-client 'client' */
 106 static int switch_matrix(struct i2c_client *client, int i, int o)
 107 {
 108         u8 byte = 0;
 109         int ret;
 110
 111         dprintk("adr:0x%02x, i:%d, o:%d\n", client->addr, i, o);
 112
 113         /* check if the pins are valid */
 114         if (0 == ((1 == i ||  3 == i ||  5 == i ||  6 == i ||  8 == i || 10 == i || 20 == i || 11 == i)
 115               && (18 == o || 17 == o || 16 == o || 15 == o || 14 == o || 13 == o)))
 116                 return -1;
 117
 118         /* to understand this, have a look at the tea6415c-specs (p.5) */
 119         switch (o) {
 120         case 18:
 121                 byte = 0x00;
 122                 break;
 123         case 14:
 124                 byte = 0x20;
 125                 break;
 126         case 16:
 127                 byte = 0x10;
 128                 break;
 129         case 17:
 130                 byte = 0x08;
 131                 break;
 132         case 15:
 133                 byte = 0x18;
 134                 break;
 135         case 13:
 136                 byte = 0x28;
 137                 break;
 138         };
 139
 140         switch (i) {
 141         case 5:
 142                 byte |= 0x00;
 143                 break;
 144         case 8:
 145                 byte |= 0x04;
 146                 break;
 147         case 3:
 148                 byte |= 0x02;
 149                 break;
 150         case 20:
 151                 byte |= 0x06;
 152                 break;
 153         case 6:
 154                 byte |= 0x01;
 155                 break;
 156         case 10:
 157                 byte |= 0x05;
 158                 break;
 159         case 1:
 160                 byte |= 0x03;
 161                 break;
 162         case 11:
 163                 byte |= 0x07;
 164                 break;
 165         };
 166
 167         ret = i2c_smbus_write_byte(client, byte);
 168         if (ret) {
 169                 dprintk("i2c_smbus_write_byte() failed, ret:%d\n", ret);
 170                 return -EIO;
 171         }
 172
 173         return ret;
 174 }
 175
 176 static int command(struct i2c_client *client, unsigned int cmd, void *arg)
 177 {
 178         struct tea6415c_multiplex *v = (struct tea6415c_multiplex *)arg;
 179         int result = 0;
 180
 181         switch (cmd) {
 182         case TEA6415C_SWITCH:
 183                 result = switch_matrix(client, v->in, v->out);
 184                 break;
 185         default:
 186                 return -ENOIOCTLCMD;
 187         }
 188
 189         return result;
 190 }
 191
 192 static struct i2c_driver driver = {
 193         .driver = {
 194                 .name   = "tea6415c",
 195         },
 196         .id     = I2C_DRIVERID_TEA6415C,
 197         .attach_adapter = attach,
 198         .detach_client  = detach,
 199         .command        = command,
 200 };
 201
 202 static struct i2c_client client_template = {
 203         .name = "tea6415c",
 204         .driver = &driver,
 205 };
 206
 207 static int __init this_module_init(void)
 208 {
 209         return i2c_add_driver(&driver);
 210 }
 211
 212 static void __exit this_module_exit(void)
 213 {
 214         i2c_del_driver(&driver);
 215 }
 216
 217 module_init(this_module_init);
 218 module_exit(this_module_exit);
 219
 220 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
 221 MODULE_DESCRIPTION("tea6415c driver");
 222 MODULE_LICENSE("GPL");