tea6420.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3    tea6420 - i2c-driver for the tea6420 by SGS Thomson
  4
  5    Copyright (C) 1998-2003 Michael Hunold <michael@mihu.de>
  6    Copyright (C) 2008 Hans Verkuil <hverkuil@kernel.org>
  7
  8    The tea6420 is a bus controlled audio-matrix with 5 stereo inputs,
  9    4 stereo outputs and gain control for each output.
 10    It is cascadable, i.e. it can be found at the addresses 0x98
 11    and 0x9a on the i2c-bus.
 12
 13    For detailed information download the specifications directly
 14    from SGS Thomson at http://www.st.com
 15
 16  */
 17
 18
 19#include <linux/module.h>
 20#include <linux/ioctl.h>
 21#include <linux/slab.h>
 22#include <linux/i2c.h>
 23#include <media/v4l2-device.h>
 24#include "tea6420.h"
 25
 26MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
 27MODULE_DESCRIPTION("tea6420 driver");
 28MODULE_LICENSE("GPL");
 29
 30static int debug;
 31module_param(debug, int, 0644);
 32
 33MODULE_PARM_DESC(debug, "Debug level (0-1)");
 34
 35
 36/* make a connection between the input 'i' and the output 'o'
 37   with gain 'g' (note: i = 6 means 'mute') */
 38static int tea6420_s_routing(struct v4l2_subdev *sd,
 39			     u32 i, u32 o, u32 config)
 40{
 41	struct i2c_client *client = v4l2_get_subdevdata(sd);
 42	int g = (o >> 4) & 0xf;
 43	u8 byte;
 44	int ret;
 45
 46	o &= 0xf;
 47	v4l2_dbg(1, debug, sd, "i=%d, o=%d, g=%d\n", i, o, g);
 48
 49	/* check if the parameters are valid */
 50	if (i < 1 || i > 6 || o < 1 || o > 4 || g < 0 || g > 6 || g % 2 != 0)
 51		return -EINVAL;
 52
 53	byte = ((o - 1) << 5);
 54	byte |= (i - 1);
 55
 56	/* to understand this, have a look at the tea6420-specs (p.5) */
 57	switch (g) {
 58	case 0:
 59		byte |= (3 << 3);
 60		break;
 61	case 2:
 62		byte |= (2 << 3);
 63		break;
 64	case 4:
 65		byte |= (1 << 3);
 66		break;
 67	case 6:
 68		break;
 69	}
 70
 71	ret = i2c_smbus_write_byte(client, byte);
 72	if (ret) {
 73		v4l2_dbg(1, debug, sd,
 74			"i2c_smbus_write_byte() failed, ret:%d\n", ret);
 75		return -EIO;
 76	}
 77	return 0;
 78}
 79
 80/* ----------------------------------------------------------------------- */
 81
 82static const struct v4l2_subdev_audio_ops tea6420_audio_ops = {
 83	.s_routing = tea6420_s_routing,
 84};
 85
 86static const struct v4l2_subdev_ops tea6420_ops = {
 87	.audio = &tea6420_audio_ops,
 88};
 89
 90static int tea6420_probe(struct i2c_client *client)
 91{
 92	struct v4l2_subdev *sd;
 93	int err, i;
 94
 95	/* let's see whether this adapter can support what we need */
 96	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE))
 97		return -EIO;
 98
 99	v4l_info(client, "chip found @ 0x%x (%s)\n",
100			client->addr << 1, client->adapter->name);
101
102	sd = devm_kzalloc(&client->dev, sizeof(*sd), GFP_KERNEL);
103	if (sd == NULL)
104		return -ENOMEM;
105	v4l2_i2c_subdev_init(sd, client, &tea6420_ops);
106
107	/* set initial values: set "mute"-input to all outputs at gain 0 */
108	err = 0;
109	for (i = 1; i < 5; i++)
110		err += tea6420_s_routing(sd, 6, i, 0);
111	if (err) {
112		v4l_dbg(1, debug, client, "could not initialize tea6420\n");
113		return -ENODEV;
114	}
115	return 0;
116}
117
118static void tea6420_remove(struct i2c_client *client)
119{
120	struct v4l2_subdev *sd = i2c_get_clientdata(client);
121
122	v4l2_device_unregister_subdev(sd);
123}
124
125static const struct i2c_device_id tea6420_id[] = {
126	{ "tea6420" },
127	{ }
128};
129MODULE_DEVICE_TABLE(i2c, tea6420_id);
130
131static struct i2c_driver tea6420_driver = {
132	.driver = {
133		.name	= "tea6420",
134	},
135	.probe		= tea6420_probe,
136	.remove		= tea6420_remove,
137	.id_table	= tea6420_id,
138};
139
140module_i2c_driver(tea6420_driver);