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->name = spi_get_device_id(spi)->name;
 154         indio_dev->modes = INDIO_DIRECT_MODE;
 155         indio_dev->info = &adc128_info;
 156
 157         indio_dev->channels = adc128_config[config].channels;
 158         indio_dev->num_channels = adc128_config[config].num_channels;
 159
 160         adc->reg = devm_regulator_get(&spi->dev, "vref");
 161         if (IS_ERR(adc->reg))
 162                 return PTR_ERR(adc->reg);
 163
 164         ret = regulator_enable(adc->reg);
 165         if (ret < 0)
 166                 return ret;
 167
 168         mutex_init(&adc->lock);
 169
 170         ret = iio_device_register(indio_dev);
 171
 172         return ret;
 173 }
 174
 175 static int adc128_remove(struct spi_device *spi)
 176 {
 177         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 178         struct adc128 *adc = iio_priv(indio_dev);
 179
 180         iio_device_unregister(indio_dev);
 181         regulator_disable(adc->reg);
 182
 183         return 0;
 184 }
 185
 186 static const struct of_device_id adc128_of_match[] = {
 187         { .compatible = "ti,adc128s052", },
 188         { .compatible = "ti,adc122s021", },
 189         { .compatible = "ti,adc124s021", },
 190         { /* sentinel */ },
 191 };
 192 MODULE_DEVICE_TABLE(of, adc128_of_match);
 193
 194 static const struct spi_device_id adc128_id[] = {
 195         { "adc128s052", 0},     /* index into adc128_config */
 196         { "adc122s021", 1},
 197         { "adc124s021", 2},
 198         { }
 199 };
 200 MODULE_DEVICE_TABLE(spi, adc128_id);
 201
 202 static struct spi_driver adc128_driver = {
 203         .driver = {
 204                 .name = "adc128s052",
 205                 .of_match_table = of_match_ptr(adc128_of_match),
 206         },
 207         .probe = adc128_probe,
 208         .remove = adc128_remove,
 209         .id_table = adc128_id,
 210 };
 211 module_spi_driver(adc128_driver);
 212
 213 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
 214 MODULE_DESCRIPTION("Texas Instruments ADC128S052");
 215 MODULE_LICENSE("GPL v2");