1 /*
2    tea6420 - i2c-driver for the tea6420 by SGS Thomson
3
4    Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
5    Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
6
7    The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
8    4 stereo outputs and gain control for each output.
9    It is cascadable, i.e. it can be found at the addresses 0x98
10    and 0x9a on the i2c-bus.
11
12    For detailed informations download the specifications directly
13    from SGS Thomson at http://www.st.com
14
15    This program is free software; you can redistribute it and/or modify
16    it under the terms of the GNU General Public License as published by
17    the Free Software Foundation; either version 2 of the License, or
18    (at your option) any later version.
19
20    This program is distributed in the hope that it will be useful,
21    but WITHOUT ANY WARRANTY; without even the implied warranty of
22    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
23    GNU General Public License for more details.
24
25    You should have received a copy of the GNU General Public License
26    along with this program; if not, write to the Free Software
27    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
28  */
29
30
31#include <linux/module.h>
32#include <linux/ioctl.h>
33#include <linux/slab.h>
34#include <linux/i2c.h>
35#include <media/v4l2-device.h>
36#include "tea6420.h"
37
38MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
39MODULE_DESCRIPTION("tea6420 driver");
40MODULE_LICENSE("GPL");
41
42static int debug;
43module_param(debug, int, 0644);
44
45MODULE_PARM_DESC(debug, "Debug level (0-1)");
46
47
48/* make a connection between the input 'i' and the output 'o'
49   with gain 'g' (note: i = 6 means 'mute') */
50static int tea6420_s_routing(struct v4l2_subdev *sd,
51			     u32 i, u32 o, u32 config)
52{
53	struct i2c_client *client = v4l2_get_subdevdata(sd);
54	int g = (o >> 4) & 0xf;
55	u8 byte;
56	int ret;
57
58	o &= 0xf;
59	v4l2_dbg(1, debug, sd, "i=%d, o=%d, g=%d\n", i, o, g);
60
61	/* check if the parameters are valid */
62	if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
63		return -EINVAL;
64
65	byte = ((o - 1) << 5);
66	byte |= (i - 1);
67
68	/* to understand this, have a look at the tea6420-specs (p.5) */
69	switch (g) {
70	case 0:
71		byte |= (3 << 3);
72		break;
73	case 2:
74		byte |= (2 << 3);
75		break;
76	case 4:
77		byte |= (1 << 3);
78		break;
79	case 6:
80		break;
81	}
82
83	ret = i2c_smbus_write_byte(client, byte);
84	if (ret) {
85		v4l2_dbg(1, debug, sd,
86			"i2c_smbus_write_byte() failed, ret:%d\n", ret);
87		return -EIO;
88	}
89	return 0;
90}
91
92/* ----------------------------------------------------------------------- */
93
94static const struct v4l2_subdev_audio_ops tea6420_audio_ops = {
95	.s_routing = tea6420_s_routing,
96};
97
98static const struct v4l2_subdev_ops tea6420_ops = {
99	.audio = &tea6420_audio_ops,
100};
101
102static int tea6420_probe(struct i2c_client *client,
103			  const struct i2c_device_id *id)
104{
105	struct v4l2_subdev *sd;
106	int err, i;
107
108	/* let's see whether this adapter can support what we need */
109	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE))
110		return -EIO;
111
112	v4l_info(client, "chip found @ 0x%x (%s)\n",
113			client->addr << 1, client->adapter->name);
114
115	sd = devm_kzalloc(&client->dev, sizeof(*sd), GFP_KERNEL);
116	if (sd == NULL)
117		return -ENOMEM;
118	v4l2_i2c_subdev_init(sd, client, &tea6420_ops);
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_s_routing(sd, 6, i, 0);
124	if (err) {
125		v4l_dbg(1, debug, client, "could not initialize tea6420\n");
126		return -ENODEV;
127	}
128	return 0;
129}
130
131static int tea6420_remove(struct i2c_client *client)
132{
133	struct v4l2_subdev *sd = i2c_get_clientdata(client);
134
135	v4l2_device_unregister_subdev(sd);
136	return 0;
137}
138
139static const struct i2c_device_id tea6420_id[] = {
140	{ "tea6420", 0 },
141	{ }
142};
143MODULE_DEVICE_TABLE(i2c, tea6420_id);
144
145static struct i2c_driver tea6420_driver = {
146	.driver = {
147		.name	= "tea6420",
148	},
149	.probe		= tea6420_probe,
150	.remove		= tea6420_remove,
151	.id_table	= tea6420_id,
152};
153
154module_i2c_driver(tea6420_driver);
155