2 * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
4 * Driver for Texas Instruments' ADC128S052 and ADC122S021 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
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/err.h>
15 #include <linux/spi/spi.h>
16 #include <linux/module.h>
17 #include <linux/iio/iio.h>
18 #include <linux/regulator/consumer.h>
20 struct adc128_configuration {
21 const struct iio_chan_spec *channels;
26 struct spi_device *spi;
28 struct regulator *reg;
31 u8 buffer[2] ____cacheline_aligned;
34 static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
38 mutex_lock(&adc->lock);
40 adc->buffer[0] = channel << 3;
43 ret = spi_write(adc->spi, &adc->buffer, 2);
45 mutex_unlock(&adc->lock);
49 ret = spi_read(adc->spi, &adc->buffer, 2);
51 mutex_unlock(&adc->lock);
56 return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF);
59 static int adc128_read_raw(struct iio_dev *indio_dev,
60 struct iio_chan_spec const *channel, int *val,
63 struct adc128 *adc = iio_priv(indio_dev);
67 case IIO_CHAN_INFO_RAW:
69 ret = adc128_adc_conversion(adc, channel->channel);
76 case IIO_CHAN_INFO_SCALE:
78 ret = regulator_get_voltage(adc->reg);
84 return IIO_VAL_FRACTIONAL_LOG2;
92 #define ADC128_VOLTAGE_CHANNEL(num) \
94 .type = IIO_VOLTAGE, \
97 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
98 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
101 static const struct iio_chan_spec adc128s052_channels[] = {
102 ADC128_VOLTAGE_CHANNEL(0),
103 ADC128_VOLTAGE_CHANNEL(1),
104 ADC128_VOLTAGE_CHANNEL(2),
105 ADC128_VOLTAGE_CHANNEL(3),
106 ADC128_VOLTAGE_CHANNEL(4),
107 ADC128_VOLTAGE_CHANNEL(5),
108 ADC128_VOLTAGE_CHANNEL(6),
109 ADC128_VOLTAGE_CHANNEL(7),
112 static const struct iio_chan_spec adc122s021_channels[] = {
113 ADC128_VOLTAGE_CHANNEL(0),
114 ADC128_VOLTAGE_CHANNEL(1),
117 static const struct adc128_configuration adc128_config[] = {
118 { adc128s052_channels, ARRAY_SIZE(adc128s052_channels) },
119 { adc122s021_channels, ARRAY_SIZE(adc122s021_channels) },
122 static const struct iio_info adc128_info = {
123 .read_raw = adc128_read_raw,
124 .driver_module = THIS_MODULE,
127 static int adc128_probe(struct spi_device *spi)
129 struct iio_dev *indio_dev;
131 int config = spi_get_device_id(spi)->driver_data;
134 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
138 adc = iio_priv(indio_dev);
141 spi_set_drvdata(spi, indio_dev);
143 indio_dev->dev.parent = &spi->dev;
144 indio_dev->name = spi_get_device_id(spi)->name;
145 indio_dev->modes = INDIO_DIRECT_MODE;
146 indio_dev->info = &adc128_info;
148 indio_dev->channels = adc128_config[config].channels;
149 indio_dev->num_channels = adc128_config[config].num_channels;
151 adc->reg = devm_regulator_get(&spi->dev, "vref");
152 if (IS_ERR(adc->reg))
153 return PTR_ERR(adc->reg);
155 ret = regulator_enable(adc->reg);
159 mutex_init(&adc->lock);
161 ret = iio_device_register(indio_dev);
166 static int adc128_remove(struct spi_device *spi)
168 struct iio_dev *indio_dev = spi_get_drvdata(spi);
169 struct adc128 *adc = iio_priv(indio_dev);
171 iio_device_unregister(indio_dev);
172 regulator_disable(adc->reg);
177 static const struct of_device_id adc128_of_match[] = {
178 { .compatible = "ti,adc128s052", },
179 { .compatible = "ti,adc122s021", },
182 MODULE_DEVICE_TABLE(of, adc128_of_match);
184 static const struct spi_device_id adc128_id[] = {
185 { "adc128s052", 0}, /* index into adc128_config */
189 MODULE_DEVICE_TABLE(spi, adc128_id);
191 static struct spi_driver adc128_driver = {
193 .name = "adc128s052",
194 .of_match_table = of_match_ptr(adc128_of_match),
196 .probe = adc128_probe,
197 .remove = adc128_remove,
198 .id_table = adc128_id,
200 module_spi_driver(adc128_driver);
202 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
203 MODULE_DESCRIPTION("Texas Instruments ADC128S052");
204 MODULE_LICENSE("GPL v2");