GNU Linux-libre 4.9.282-gnu1
[releases.git] / drivers / iio / adc / ti-adc128s052.c
1 /*
2  * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
3  *
4  * Driver for Texas Instruments' ADC128S052, ADC122S021 and ADC124S021 ADC chip.
5  * Datasheets can be found here:
6  * http://www.ti.com/lit/ds/symlink/adc128s052.pdf
7  * http://www.ti.com/lit/ds/symlink/adc122s021.pdf
8  * http://www.ti.com/lit/ds/symlink/adc124s021.pdf
9  *
10  * This program is free software; you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License version 2 as
12  * published by the Free Software Foundation.
13  */
14
15 #include <linux/err.h>
16 #include <linux/spi/spi.h>
17 #include <linux/module.h>
18 #include <linux/iio/iio.h>
19 #include <linux/regulator/consumer.h>
20
21 struct adc128_configuration {
22         const struct iio_chan_spec      *channels;
23         u8                              num_channels;
24 };
25
26 struct adc128 {
27         struct spi_device *spi;
28
29         struct regulator *reg;
30         struct mutex lock;
31
32         u8 buffer[2] ____cacheline_aligned;
33 };
34
35 static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
36 {
37         int ret;
38
39         mutex_lock(&adc->lock);
40
41         adc->buffer[0] = channel << 3;
42         adc->buffer[1] = 0;
43
44         ret = spi_write(adc->spi, &adc->buffer, 2);
45         if (ret < 0) {
46                 mutex_unlock(&adc->lock);
47                 return ret;
48         }
49
50         ret = spi_read(adc->spi, &adc->buffer, 2);
51
52         mutex_unlock(&adc->lock);
53
54         if (ret < 0)
55                 return ret;
56
57         return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF);
58 }
59
60 static int adc128_read_raw(struct iio_dev *indio_dev,
61                            struct iio_chan_spec const *channel, int *val,
62                            int *val2, long mask)
63 {
64         struct adc128 *adc = iio_priv(indio_dev);
65         int ret;
66
67         switch (mask) {
68         case IIO_CHAN_INFO_RAW:
69
70                 ret = adc128_adc_conversion(adc, channel->channel);
71                 if (ret < 0)
72                         return ret;
73
74                 *val = ret;
75                 return IIO_VAL_INT;
76
77         case IIO_CHAN_INFO_SCALE:
78
79                 ret = regulator_get_voltage(adc->reg);
80                 if (ret < 0)
81                         return ret;
82
83                 *val = ret / 1000;
84                 *val2 = 12;
85                 return IIO_VAL_FRACTIONAL_LOG2;
86
87         default:
88                 return -EINVAL;
89         }
90
91 }
92
93 #define ADC128_VOLTAGE_CHANNEL(num)     \
94         { \
95                 .type = IIO_VOLTAGE, \
96                 .indexed = 1, \
97                 .channel = (num), \
98                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
99                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
100         }
101
102 static const struct iio_chan_spec adc128s052_channels[] = {
103         ADC128_VOLTAGE_CHANNEL(0),
104         ADC128_VOLTAGE_CHANNEL(1),
105         ADC128_VOLTAGE_CHANNEL(2),
106         ADC128_VOLTAGE_CHANNEL(3),
107         ADC128_VOLTAGE_CHANNEL(4),
108         ADC128_VOLTAGE_CHANNEL(5),
109         ADC128_VOLTAGE_CHANNEL(6),
110         ADC128_VOLTAGE_CHANNEL(7),
111 };
112
113 static const struct iio_chan_spec adc122s021_channels[] = {
114         ADC128_VOLTAGE_CHANNEL(0),
115         ADC128_VOLTAGE_CHANNEL(1),
116 };
117
118 static const struct iio_chan_spec adc124s021_channels[] = {
119         ADC128_VOLTAGE_CHANNEL(0),
120         ADC128_VOLTAGE_CHANNEL(1),
121         ADC128_VOLTAGE_CHANNEL(2),
122         ADC128_VOLTAGE_CHANNEL(3),
123 };
124
125 static const struct adc128_configuration adc128_config[] = {
126         { adc128s052_channels, ARRAY_SIZE(adc128s052_channels) },
127         { adc122s021_channels, ARRAY_SIZE(adc122s021_channels) },
128         { adc124s021_channels, ARRAY_SIZE(adc124s021_channels) },
129 };
130
131 static const struct iio_info adc128_info = {
132         .read_raw = adc128_read_raw,
133         .driver_module = THIS_MODULE,
134 };
135
136 static int adc128_probe(struct spi_device *spi)
137 {
138         struct iio_dev *indio_dev;
139         struct adc128 *adc;
140         int config = spi_get_device_id(spi)->driver_data;
141         int ret;
142
143         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
144         if (!indio_dev)
145                 return -ENOMEM;
146
147         adc = iio_priv(indio_dev);
148         adc->spi = spi;
149
150         spi_set_drvdata(spi, indio_dev);
151
152         indio_dev->dev.parent = &spi->dev;
153         indio_dev->dev.of_node = spi->dev.of_node;
154         indio_dev->name = spi_get_device_id(spi)->name;
155         indio_dev->modes = INDIO_DIRECT_MODE;
156         indio_dev->info = &adc128_info;
157
158         indio_dev->channels = adc128_config[config].channels;
159         indio_dev->num_channels = adc128_config[config].num_channels;
160
161         adc->reg = devm_regulator_get(&spi->dev, "vref");
162         if (IS_ERR(adc->reg))
163                 return PTR_ERR(adc->reg);
164
165         ret = regulator_enable(adc->reg);
166         if (ret < 0)
167                 return ret;
168
169         mutex_init(&adc->lock);
170
171         ret = iio_device_register(indio_dev);
172
173         return ret;
174 }
175
176 static int adc128_remove(struct spi_device *spi)
177 {
178         struct iio_dev *indio_dev = spi_get_drvdata(spi);
179         struct adc128 *adc = iio_priv(indio_dev);
180
181         iio_device_unregister(indio_dev);
182         regulator_disable(adc->reg);
183
184         return 0;
185 }
186
187 static const struct of_device_id adc128_of_match[] = {
188         { .compatible = "ti,adc128s052", },
189         { .compatible = "ti,adc122s021", },
190         { .compatible = "ti,adc124s021", },
191         { /* sentinel */ },
192 };
193 MODULE_DEVICE_TABLE(of, adc128_of_match);
194
195 static const struct spi_device_id adc128_id[] = {
196         { "adc128s052", 0},     /* index into adc128_config */
197         { "adc122s021", 1},
198         { "adc124s021", 2},
199         { }
200 };
201 MODULE_DEVICE_TABLE(spi, adc128_id);
202
203 static struct spi_driver adc128_driver = {
204         .driver = {
205                 .name = "adc128s052",
206                 .of_match_table = of_match_ptr(adc128_of_match),
207         },
208         .probe = adc128_probe,
209         .remove = adc128_remove,
210         .id_table = adc128_id,
211 };
212 module_spi_driver(adc128_driver);
213
214 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
215 MODULE_DESCRIPTION("Texas Instruments ADC128S052");
216 MODULE_LICENSE("GPL v2");