[go: nahoru, domu]
1/*
2 * Copyright (C) 2012 Avionic Design GmbH
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/err.h>
10#include <linux/i2c.h>
11#include <linux/module.h>
12#include <linux/of.h>
13
14#include <linux/iio/iio.h>
15#include <linux/regulator/consumer.h>
16
17struct adc081c {
18	struct i2c_client *i2c;
19	struct regulator *ref;
20};
21
22#define REG_CONV_RES 0x00
23
24static int adc081c_read_raw(struct iio_dev *iio,
25			    struct iio_chan_spec const *channel, int *value,
26			    int *shift, long mask)
27{
28	struct adc081c *adc = iio_priv(iio);
29	int err;
30
31	switch (mask) {
32	case IIO_CHAN_INFO_RAW:
33		err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
34		if (err < 0)
35			return err;
36
37		*value = (err >> 4) & 0xff;
38		return IIO_VAL_INT;
39
40	case IIO_CHAN_INFO_SCALE:
41		err = regulator_get_voltage(adc->ref);
42		if (err < 0)
43			return err;
44
45		*value = err / 1000;
46		*shift = 8;
47
48		return IIO_VAL_FRACTIONAL_LOG2;
49
50	default:
51		break;
52	}
53
54	return -EINVAL;
55}
56
57static const struct iio_chan_spec adc081c_channel = {
58	.type = IIO_VOLTAGE,
59	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
60	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
61};
62
63static const struct iio_info adc081c_info = {
64	.read_raw = adc081c_read_raw,
65	.driver_module = THIS_MODULE,
66};
67
68static int adc081c_probe(struct i2c_client *client,
69			 const struct i2c_device_id *id)
70{
71	struct iio_dev *iio;
72	struct adc081c *adc;
73	int err;
74
75	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
76		return -ENODEV;
77
78	iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
79	if (!iio)
80		return -ENOMEM;
81
82	adc = iio_priv(iio);
83	adc->i2c = client;
84
85	adc->ref = devm_regulator_get(&client->dev, "vref");
86	if (IS_ERR(adc->ref))
87		return PTR_ERR(adc->ref);
88
89	err = regulator_enable(adc->ref);
90	if (err < 0)
91		return err;
92
93	iio->dev.parent = &client->dev;
94	iio->name = dev_name(&client->dev);
95	iio->modes = INDIO_DIRECT_MODE;
96	iio->info = &adc081c_info;
97
98	iio->channels = &adc081c_channel;
99	iio->num_channels = 1;
100
101	err = iio_device_register(iio);
102	if (err < 0)
103		goto regulator_disable;
104
105	i2c_set_clientdata(client, iio);
106
107	return 0;
108
109regulator_disable:
110	regulator_disable(adc->ref);
111
112	return err;
113}
114
115static int adc081c_remove(struct i2c_client *client)
116{
117	struct iio_dev *iio = i2c_get_clientdata(client);
118	struct adc081c *adc = iio_priv(iio);
119
120	iio_device_unregister(iio);
121	regulator_disable(adc->ref);
122
123	return 0;
124}
125
126static const struct i2c_device_id adc081c_id[] = {
127	{ "adc081c", 0 },
128	{ }
129};
130MODULE_DEVICE_TABLE(i2c, adc081c_id);
131
132#ifdef CONFIG_OF
133static const struct of_device_id adc081c_of_match[] = {
134	{ .compatible = "ti,adc081c" },
135	{ }
136};
137MODULE_DEVICE_TABLE(of, adc081c_of_match);
138#endif
139
140static struct i2c_driver adc081c_driver = {
141	.driver = {
142		.name = "adc081c",
143		.owner = THIS_MODULE,
144		.of_match_table = of_match_ptr(adc081c_of_match),
145	},
146	.probe = adc081c_probe,
147	.remove = adc081c_remove,
148	.id_table = adc081c_id,
149};
150module_i2c_driver(adc081c_driver);
151
152MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
153MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
154MODULE_LICENSE("GPL v2");
155