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
30#include <linux/module.h>
31#include <linux/ioctl.h>
32#include <linux/i2c.h>
33
34#include "tea6420.h"
35
36static int debug = 0;		/* insmod parameter */
37module_param(debug, int, 0644);
38MODULE_PARM_DESC(debug, "Turn on/off device debugging (default:off).");
39#define dprintk(args...) \
40	    do { if (debug) { printk("%s: %s()[%d]: ", KBUILD_MODNAME, __FUNCTION__, __LINE__); printk(args); } } while (0)
41
42/* addresses to scan, found only at 0x4c and/or 0x4d (7-Bit) */
43static unsigned short normal_i2c[] = { I2C_ADDR_TEA6420_1, I2C_ADDR_TEA6420_2, I2C_CLIENT_END };
44
45/* magic definition of all other variables and things */
46I2C_CLIENT_INSMOD;
47
48static struct i2c_driver driver;
49static 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') */
53static 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 */
92static 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 = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
104	if (0 == client) {
105		return -ENOMEM;
106	}
107
108	/* fill client structure */
109	memcpy(client, &client_template, sizeof(struct i2c_client));
110	client->addr = address;
111	client->adapter = adapter;
112
113	/* tell the i2c layer a new client has arrived */
114	if (0 != (err = i2c_attach_client(client))) {
115		kfree(client);
116		return err;
117	}
118
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);
123	}
124	if (err) {
125		dprintk("could not initialize tea6420\n");
126		kfree(client);
127		return -ENODEV;
128	}
129
130	printk("tea6420: detected @ 0x%02x on adapter %s\n", address, &client->adapter->name[0]);
131
132	return 0;
133}
134
135static int attach(struct i2c_adapter *adapter)
136{
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;
141	}
142
143	return i2c_probe(adapter, &addr_data, &tea6420_detect);
144}
145
146static int detach(struct i2c_client *client)
147{
148	int ret = i2c_detach_client(client);
149	kfree(client);
150	return ret;
151}
152
153static int command(struct i2c_client *client, unsigned int cmd, void *arg)
154{
155	struct tea6420_multiplex *a = (struct tea6420_multiplex *)arg;
156	int result = 0;
157
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;
164	}
165
166	return result;
167}
168
169static struct i2c_driver driver = {
170	.driver = {
171		.name = "tea6420",
172	},
173	.id	= I2C_DRIVERID_TEA6420,
174	.attach_adapter	= attach,
175	.detach_client	= detach,
176	.command	= command,
177};
178
179static struct i2c_client client_template = {
180	.name = "tea6420",
181	.driver = &driver,
182};
183
184static int __init this_module_init(void)
185{
186	return i2c_add_driver(&driver);
187}
188
189static void __exit this_module_exit(void)
190{
191	i2c_del_driver(&driver);
192}
193
194module_init(this_module_init);
195module_exit(this_module_exit);
196
197MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
198MODULE_DESCRIPTION("tea6420 driver");
199MODULE_LICENSE("GPL");
200