Linux v2.6.15-rc7
[pohmelfs.git] / drivers / media / video / tea6420.c
blob17975c19da5ee376f08ba2b7e98b96d4469b519b
1 /*
2 tea6420 - i2c-driver for the tea6420 by SGS Thomson
4 Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
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.
11 For detailed informations download the specifications directly
12 from SGS Thomson at http://www.st.com
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.
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.
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.
29 #include <linux/module.h>
30 #include <linux/ioctl.h>
31 #include <linux/i2c.h>
33 #include "tea6420.h"
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)
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 };
44 /* magic definition of all other variables and things */
45 I2C_CLIENT_INSMOD;
47 static struct i2c_driver driver;
48 static struct i2c_client client_template;
50 /* make a connection between the input 'i' and the output 'o'
51 with gain 'g' for the tea6420-client 'client' (note: i = 6 means 'mute') */
52 static int tea6420_switch(struct i2c_client *client, int i, int o, int g)
54 u8 byte = 0;
55 int ret;
57 dprintk("adr:0x%02x, i:%d, o:%d, g:%d\n", client->addr, i, o, g);
59 /* check if the paramters are valid */
60 if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
61 return -1;
63 byte = ((o - 1) << 5);
64 byte |= (i - 1);
66 /* to understand this, have a look at the tea6420-specs (p.5) */
67 switch (g) {
68 case 0:
69 byte |= (3 << 3);
70 break;
71 case 2:
72 byte |= (2 << 3);
73 break;
74 case 4:
75 byte |= (1 << 3);
76 break;
77 case 6:
78 break;
81 ret = i2c_smbus_write_byte(client, byte);
82 if (ret) {
83 dprintk("i2c_smbus_write_byte() failed, ret:%d\n", ret);
84 return -EIO;
87 return 0;
90 /* this function is called by i2c_probe */
91 static int tea6420_detect(struct i2c_adapter *adapter, int address, int kind)
93 struct i2c_client *client;
94 int err = 0, i = 0;
96 /* let's see whether this adapter can support what we need */
97 if (0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {
98 return 0;
101 /* allocate memory for client structure */
102 client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
103 if (0 == client) {
104 return -ENOMEM;
106 memset(client, 0x0, sizeof(struct i2c_client));
108 /* fill client structure */
109 memcpy(client, &client_template, sizeof(struct i2c_client));
110 client->addr = address;
111 client->adapter = adapter;
113 /* tell the i2c layer a new client has arrived */
114 if (0 != (err = i2c_attach_client(client))) {
115 kfree(client);
116 return err;
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);
124 if (err) {
125 dprintk("could not initialize tea6420\n");
126 kfree(client);
127 return -ENODEV;
130 printk("tea6420: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
132 return 0;
135 static int attach(struct i2c_adapter *adapter)
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;
143 return i2c_probe(adapter, &addr_data, &tea6420_detect);
146 static int detach(struct i2c_client *client)
148 int ret = i2c_detach_client(client);
149 kfree(client);
150 return ret;
153 static int command(struct i2c_client *client, unsigned int cmd, void *arg)
155 struct tea6420_multiplex *a = (struct tea6420_multiplex *)arg;
156 int result = 0;
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;
166 return result;
169 static struct i2c_driver driver = {
170 .owner = THIS_MODULE,
171 .name = "tea6420",
172 .id = I2C_DRIVERID_TEA6420,
173 .flags = I2C_DF_NOTIFY,
174 .attach_adapter = attach,
175 .detach_client = detach,
176 .command = command,
179 static struct i2c_client client_template = {
180 .name = "tea6420",
181 .driver = &driver,
184 static int __init this_module_init(void)
186 return i2c_add_driver(&driver);
189 static void __exit this_module_exit(void)
191 i2c_del_driver(&driver);
194 module_init(this_module_init);
195 module_exit(this_module_exit);
197 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
198 MODULE_DESCRIPTION("tea6420 driver");
199 MODULE_LICENSE("GPL");