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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@xs4all.nl>
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  
26  MODULE_AUTHOR("Michael Hunold <michael@mihu.de>");
27  MODULE_DESCRIPTION("tea6420 driver");
28  MODULE_LICENSE("GPL");
29  
30  static int debug;
31  module_param(debug, int, 0644);
32  
33  MODULE_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') */
tea6420_s_routing(struct v4l2_subdev * sd,u32 i,u32 o,u32 config)38  static 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  
82  static const struct v4l2_subdev_audio_ops tea6420_audio_ops = {
83  	.s_routing = tea6420_s_routing,
84  };
85  
86  static const struct v4l2_subdev_ops tea6420_ops = {
87  	.audio = &tea6420_audio_ops,
88  };
89  
tea6420_probe(struct i2c_client * client,const struct i2c_device_id * id)90  static int tea6420_probe(struct i2c_client *client,
91  			  const struct i2c_device_id *id)
92  {
93  	struct v4l2_subdev *sd;
94  	int err, i;
95  
96  	/* let's see whether this adapter can support what we need */
97  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE))
98  		return -EIO;
99  
100  	v4l_info(client, "chip found @ 0x%x (%s)\n",
101  			client->addr << 1, client->adapter->name);
102  
103  	sd = devm_kzalloc(&client->dev, sizeof(*sd), GFP_KERNEL);
104  	if (sd == NULL)
105  		return -ENOMEM;
106  	v4l2_i2c_subdev_init(sd, client, &tea6420_ops);
107  
108  	/* set initial values: set "mute"-input to all outputs at gain 0 */
109  	err = 0;
110  	for (i = 1; i < 5; i++)
111  		err += tea6420_s_routing(sd, 6, i, 0);
112  	if (err) {
113  		v4l_dbg(1, debug, client, "could not initialize tea6420\n");
114  		return -ENODEV;
115  	}
116  	return 0;
117  }
118  
tea6420_remove(struct i2c_client * client)119  static int tea6420_remove(struct i2c_client *client)
120  {
121  	struct v4l2_subdev *sd = i2c_get_clientdata(client);
122  
123  	v4l2_device_unregister_subdev(sd);
124  	return 0;
125  }
126  
127  static const struct i2c_device_id tea6420_id[] = {
128  	{ "tea6420", 0 },
129  	{ }
130  };
131  MODULE_DEVICE_TABLE(i2c, tea6420_id);
132  
133  static struct i2c_driver tea6420_driver = {
134  	.driver = {
135  		.name	= "tea6420",
136  	},
137  	.probe		= tea6420_probe,
138  	.remove		= tea6420_remove,
139  	.id_table	= tea6420_id,
140  };
141  
142  module_i2c_driver(tea6420_driver);
143