summaryrefslogtreecommitdiffstats
path: root/drivers/iio/adc/ti-adc128s052.c
blob: 655cb564ec54af8696229853bf5f418389e49be9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
/*
 * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
 *
 * Driver for Texas Instruments' ADC128S052 ADC chip.
 * Datasheet can be found here:
 * http://www.ti.com/lit/ds/symlink/adc128s052.pdf
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/err.h>
#include <linux/spi/spi.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/regulator/consumer.h>

struct adc128 {
	struct spi_device *spi;

	struct regulator *reg;
	struct mutex lock;

	u8 buffer[2] ____cacheline_aligned;
};

static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
{
	int ret;

	mutex_lock(&adc->lock);

	adc->buffer[0] = channel << 3;
	adc->buffer[1] = 0;

	ret = spi_write(adc->spi, &adc->buffer, 2);
	if (ret < 0) {
		mutex_unlock(&adc->lock);
		return ret;
	}

	ret = spi_read(adc->spi, &adc->buffer, 2);

	mutex_unlock(&adc->lock);

	if (ret < 0)
		return ret;

	return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF);
}

static int adc128_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *channel, int *val,
			   int *val2, long mask)
{
	struct adc128 *adc = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:

		ret = adc128_adc_conversion(adc, channel->channel);
		if (ret < 0)
			return ret;

		*val = ret;
		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		ret = regulator_get_voltage(adc->reg);
		if (ret < 0)
			return ret;

		*val = ret / 1000;
		*val2 = 12;
		return IIO_VAL_FRACTIONAL_LOG2;

	default:
		return -EINVAL;
	}

}

#define ADC128_VOLTAGE_CHANNEL(num)	\
	{ \
		.type = IIO_VOLTAGE, \
		.indexed = 1, \
		.channel = (num), \
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
	}

static const struct iio_chan_spec adc128_channels[] = {
	ADC128_VOLTAGE_CHANNEL(0),
	ADC128_VOLTAGE_CHANNEL(1),
	ADC128_VOLTAGE_CHANNEL(2),
	ADC128_VOLTAGE_CHANNEL(3),
	ADC128_VOLTAGE_CHANNEL(4),
	ADC128_VOLTAGE_CHANNEL(5),
	ADC128_VOLTAGE_CHANNEL(6),
	ADC128_VOLTAGE_CHANNEL(7),
};

static const struct iio_info adc128_info = {
	.read_raw = adc128_read_raw,
	.driver_module = THIS_MODULE,
};

static int adc128_probe(struct spi_device *spi)
{
	struct iio_dev *indio_dev;
	struct adc128 *adc;
	int ret;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
	if (!indio_dev)
		return -ENOMEM;

	adc = iio_priv(indio_dev);
	adc->spi = spi;

	spi_set_drvdata(spi, indio_dev);

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &adc128_info;

	indio_dev->channels = adc128_channels;
	indio_dev->num_channels = ARRAY_SIZE(adc128_channels);

	adc->reg = devm_regulator_get(&spi->dev, "vref");
	if (IS_ERR(adc->reg))
		return PTR_ERR(adc->reg);

	ret = regulator_enable(adc->reg);
	if (ret < 0)
		return ret;

	mutex_init(&adc->lock);

	ret = iio_device_register(indio_dev);

	return ret;
}

static int adc128_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct adc128 *adc = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	regulator_disable(adc->reg);

	return 0;
}

static const struct spi_device_id adc128_id[] = {
	{ "adc128s052", 0},
	{ }
};
MODULE_DEVICE_TABLE(spi, adc128_id);

static struct spi_driver adc128_driver = {
	.driver = {
		.name = "adc128s052",
		.owner = THIS_MODULE,
	},
	.probe = adc128_probe,
	.remove = adc128_remove,
	.id_table = adc128_id,
};
module_spi_driver(adc128_driver);

MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
MODULE_DESCRIPTION("Texas Instruments ADC128S052");
MODULE_LICENSE("GPL v2");
OpenPOWER on IntegriCloud