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 /* unique ID allocation */
52 static int tea6420_id = 0;
53
54 /* make a connection between the input 'i' and the output 'o'
55 with gain 'g' for the tea6420-client 'client' (note: i = 6 means 'mute') */
56 static int tea6420_switch(struct i2c_client *client, int i, int o, int g)
57 {
58 u8 byte = 0;
59 int ret;
60
61 dprintk("adr:0x%02x, i:%d, o:%d, g:%d\n", client->addr, i, o, g);
62
63 /* check if the paramters are valid */
64 if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
65 return -1;
66
67 byte = ((o - 1) << 5);
68 byte |= (i - 1);
69
70 /* to understand this, have a look at the tea6420-specs (p.5) */
71 switch (g) {
72 case 0:
73 byte |= (3 << 3);
74 break;
75 case 2:
76 byte |= (2 << 3);
77 break;
78 case 4:
79 byte |= (1 << 3);
80 break;
81 case 6:
82 break;
83 }
84
85 ret = i2c_smbus_write_byte(client, byte);
86 if (ret) {
87 dprintk("i2c_smbus_write_byte() failed, ret:%d\n", ret);
88 return -EIO;
89 }
90
91 return 0;
92 }
93
94 /* this function is called by i2c_probe */
95 static int tea6420_detect(struct i2c_adapter *adapter, int address, int kind)
96 {
97 struct i2c_client *client;
98 int err = 0, i = 0;
99
100 /* let's see whether this adapter can support what we need */
101 if (0 == i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE)) {
102 return 0;
103 }
104
105 /* allocate memory for client structure */
106 client = kmalloc(sizeof(struct i2c_client), GFP_KERNEL);
107 if (0 == client) {
108 return -ENOMEM;
109 }
110 memset(client, 0x0, sizeof(struct i2c_client));
111
112 /* fill client structure */
113 memcpy(client, &client_template, sizeof(struct i2c_client));
114 client->id = tea6420_id++;
115 client->addr = address;
116 client->adapter = adapter;
117
118 /* tell the i2c layer a new client has arrived */
119 if (0 != (err = i2c_attach_client(client))) {
120 kfree(client);
121 return err;
122 }
123
124 /* set initial values: set "mute"-input to all outputs at gain 0 */
125 err = 0;
126 for (i = 1; i < 5; i++) {
127 err += tea6420_switch(client, 6, i, 0);
128 }
129 if (err) {
130 dprintk("could not initialize tea6420\n");
131 kfree(client);
132 return -ENODEV;
133 }
134
135 printk("tea6420: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
136
137 return 0;
138 }
139
140 static int attach(struct i2c_adapter *adapter)
141 {
142 /* let's see whether this is a know adapter we can attach to */
143 if (adapter->id != I2C_ALGO_SAA7146) {
144 dprintk("refusing to probe on unknown adapter [name='%s',id=0x%x]\n", adapter->name, adapter->id);
145 return -ENODEV;
146 }
147
148 return i2c_probe(adapter, &addr_data, &tea6420_detect);
149 }
150
151 static int detach(struct i2c_client *client)
152 {
153 int ret = i2c_detach_client(client);
154 kfree(client);
155 return ret;
156 }
157
158 static int command(struct i2c_client *client, unsigned int cmd, void *arg)
159 {
160 struct tea6420_multiplex *a = (struct tea6420_multiplex *)arg;
161 int result = 0;
162
163 switch (cmd) {
164 case TEA6420_SWITCH:
165 result = tea6420_switch(client, a->in, a->out, a->gain);
166 break;
167 default:
168 return -ENOIOCTLCMD;
169 }
170
171 return result;
172 }
173
174 static struct i2c_driver driver = {
175 .owner = THIS_MODULE,
176 .name = "tea6420",
177 .id = I2C_DRIVERID_TEA6420,
178 .flags = I2C_DF_NOTIFY,
179 .attach_adapter = attach,
180 .detach_client = detach,
181 .command = command,
182 };
183
184 static struct i2c_client client_template = {
185 I2C_DEVNAME("tea6420"),
186 .driver = &driver,
187 };
188
189 static int __init this_module_init(void)
190 {
191 return i2c_add_driver(&driver);
192 }
193
194 static void __exit this_module_exit(void)
195 {
196 i2c_del_driver(&driver);
197 }
198
199 module_init(this_module_init);
200 module_exit(this_module_exit);
201
202 MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
203 MODULE_DESCRIPTION("tea6420 driver");
204 MODULE_LICENSE("GPL");
205
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