drivers/iio/adc/ti-adc128s052.c

   1 /*
   2  * Copyright (C) 2014 Angelo Compagnucci <angelo.compagnucci@gmail.com>
   3  *
   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
   8  *
   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.
  12  */
  13
  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>
  19
  20 struct adc128_configuration {
  21         const struct iio_chan_spec      *channels;
  22         u8                              num_channels;
  23 };
  24
  25 struct adc128 {
  26         struct spi_device *spi;
  27
  28         struct regulator *reg;
  29         struct mutex lock;
  30
  31         u8 buffer[2] ____cacheline_aligned;
  32 };
  33
  34 static int adc128_adc_conversion(struct adc128 *adc, u8 channel)
  35 {
  36         int ret;
  37
  38         mutex_lock(&adc->lock);
  39
  40         adc->buffer[0] = channel << 3;
  41         adc->buffer[1] = 0;
  42
  43         ret = spi_write(adc->spi, &adc->buffer, 2);
  44         if (ret < 0) {
  45                 mutex_unlock(&adc->lock);
  46                 return ret;
  47         }
  48
  49         ret = spi_read(adc->spi, &adc->buffer, 2);
  50
  51         mutex_unlock(&adc->lock);
  52
  53         if (ret < 0)
  54                 return ret;
  55
  56         return ((adc->buffer[0] << 8 | adc->buffer[1]) & 0xFFF);
  57 }
  58
  59 static int adc128_read_raw(struct iio_dev *indio_dev,
  60                            struct iio_chan_spec const *channel, int *val,
  61                            int *val2, long mask)
  62 {
  63         struct adc128 *adc = iio_priv(indio_dev);
  64         int ret;
  65
  66         switch (mask) {
  67         case IIO_CHAN_INFO_RAW:
  68
  69                 ret = adc128_adc_conversion(adc, channel->channel);
  70                 if (ret < 0)
  71                         return ret;
  72
  73                 *val = ret;
  74                 return IIO_VAL_INT;
  75
  76         case IIO_CHAN_INFO_SCALE:
  77
  78                 ret = regulator_get_voltage(adc->reg);
  79                 if (ret < 0)
  80                         return ret;
  81
  82                 *val = ret / 1000;
  83                 *val2 = 12;
  84                 return IIO_VAL_FRACTIONAL_LOG2;
  85
  86         default:
  87                 return -EINVAL;
  88         }
  89
  90 }
  91
  92 #define ADC128_VOLTAGE_CHANNEL(num)     \
  93         { \
  94                 .type = IIO_VOLTAGE, \
  95                 .indexed = 1, \
  96                 .channel = (num), \
  97                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
  98                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
  99         }
 100
 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),
 110 };
 111
 112 static const struct iio_chan_spec adc122s021_channels[] = {
 113         ADC128_VOLTAGE_CHANNEL(0),
 114         ADC128_VOLTAGE_CHANNEL(1),
 115 };
 116
 117 static const struct adc128_configuration adc128_config[] = {
 118         { adc128s052_channels, ARRAY_SIZE(adc128s052_channels) },
 119         { adc122s021_channels, ARRAY_SIZE(adc122s021_channels) },
 120 };
 121
 122 static const struct iio_info adc128_info = {
 123         .read_raw = adc128_read_raw,
 124         .driver_module = THIS_MODULE,
 125 };
 126
 127 static int adc128_probe(struct spi_device *spi)
 128 {
 129         struct iio_dev *indio_dev;
 130         struct adc128 *adc;
 131         int config = spi_get_device_id(spi)->driver_data;
 132         int ret;
 133
 134         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
 135         if (!indio_dev)
 136                 return -ENOMEM;
 137
 138         adc = iio_priv(indio_dev);
 139         adc->spi = spi;
 140
 141         spi_set_drvdata(spi, indio_dev);
 142
 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;
 147
 148         indio_dev->channels = adc128_config[config].channels;
 149         indio_dev->num_channels = adc128_config[config].num_channels;
 150
 151         adc->reg = devm_regulator_get(&spi->dev, "vref");
 152         if (IS_ERR(adc->reg))
 153                 return PTR_ERR(adc->reg);
 154
 155         ret = regulator_enable(adc->reg);
 156         if (ret < 0)
 157                 return ret;
 158
 159         mutex_init(&adc->lock);
 160
 161         ret = iio_device_register(indio_dev);
 162
 163         return ret;
 164 }
 165
 166 static int adc128_remove(struct spi_device *spi)
 167 {
 168         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 169         struct adc128 *adc = iio_priv(indio_dev);
 170
 171         iio_device_unregister(indio_dev);
 172         regulator_disable(adc->reg);
 173
 174         return 0;
 175 }
 176
 177 static const struct of_device_id adc128_of_match[] = {
 178         { .compatible = "ti,adc128s052", },
 179         { .compatible = "ti,adc122s021", },
 180         { /* sentinel */ },
 181 };
 182 MODULE_DEVICE_TABLE(of, adc128_of_match);
 183
 184 static const struct spi_device_id adc128_id[] = {
 185         { "adc128s052", 0},     /* index into adc128_config */
 186         { "adc122s021", 1},
 187         { }
 188 };
 189 MODULE_DEVICE_TABLE(spi, adc128_id);
 190
 191 static struct spi_driver adc128_driver = {
 192         .driver = {
 193                 .name = "adc128s052",
 194                 .of_match_table = of_match_ptr(adc128_of_match),
 195         },
 196         .probe = adc128_probe,
 197         .remove = adc128_remove,
 198         .id_table = adc128_id,
 199 };
 200 module_spi_driver(adc128_driver);
 201
 202 MODULE_AUTHOR("Angelo Compagnucci <angelo.compagnucci@gmail.com>");
 203 MODULE_DESCRIPTION("Texas Instruments ADC128S052");
 204 MODULE_LICENSE("GPL v2");