drivers/iio/adc/max11205.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Maxim MAX11205 16-Bit Delta-Sigma ADC
   4  *
   5  * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-max11205.pdf
   6  * Copyright (C) 2022 Analog Devices, Inc.
   7  * Author: Ramona Bolboaca <ramona.bolboaca@analog.com>
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/module.h>
  12 #include <linux/regulator/consumer.h>
  13 #include <linux/spi/spi.h>
  14
  15 #include <linux/iio/iio.h>
  16 #include <linux/iio/adc/ad_sigma_delta.h>
  17
  18 #define MAX11205_BIT_SCALE      15
  19 #define MAX11205A_OUT_DATA_RATE 116
  20 #define MAX11205B_OUT_DATA_RATE 13
  21
  22 enum max11205_chip_type {
  23         TYPE_MAX11205A,
  24         TYPE_MAX11205B,
  25 };
  26
  27 struct max11205_chip_info {
  28         unsigned int    out_data_rate;
  29         const char      *name;
  30 };
  31
  32 struct max11205_state {
  33         const struct max11205_chip_info *chip_info;
  34         struct regulator                *vref;
  35         struct ad_sigma_delta           sd;
  36 };
  37
  38 static const struct ad_sigma_delta_info max11205_sigma_delta_info = {
  39         .has_registers = false,
  40 };
  41
  42 static int max11205_read_raw(struct iio_dev *indio_dev,
  43                              struct iio_chan_spec const *chan,
  44                              int *val, int *val2, long mask)
  45 {
  46         struct max11205_state *st = iio_priv(indio_dev);
  47         int reg_mv;
  48
  49         switch (mask) {
  50         case IIO_CHAN_INFO_RAW:
  51                 return ad_sigma_delta_single_conversion(indio_dev, chan, val);
  52         case IIO_CHAN_INFO_SCALE:
  53                 reg_mv = regulator_get_voltage(st->vref);
  54                 if (reg_mv < 0)
  55                         return reg_mv;
  56                 reg_mv /= 1000;
  57                 *val = reg_mv;
  58                 *val2 = MAX11205_BIT_SCALE;
  59                 return IIO_VAL_FRACTIONAL_LOG2;
  60         case IIO_CHAN_INFO_SAMP_FREQ:
  61                 *val = st->chip_info->out_data_rate;
  62                 return IIO_VAL_INT;
  63         default:
  64                 return -EINVAL;
  65         }
  66 }
  67
  68 static const struct iio_info max11205_iio_info = {
  69         .read_raw = max11205_read_raw,
  70         .validate_trigger = ad_sd_validate_trigger,
  71 };
  72
  73 static const struct iio_chan_spec max11205_channels[] = {
  74         {
  75                 .type = IIO_VOLTAGE,
  76                 .indexed = 1,
  77                 .scan_type = {
  78                         .sign = 's',
  79                         .realbits = 16,
  80                         .storagebits = 16,
  81                         .endianness = IIO_BE,
  82                 },
  83                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
  84                                       BIT(IIO_CHAN_INFO_SAMP_FREQ) |
  85                                       BIT(IIO_CHAN_INFO_SCALE),
  86         },
  87 };
  88
  89 static const struct max11205_chip_info max11205_chip_info[] = {
  90         [TYPE_MAX11205A] = {
  91                 .out_data_rate = MAX11205A_OUT_DATA_RATE,
  92                 .name = "max11205a",
  93         },
  94         [TYPE_MAX11205B] = {
  95                 .out_data_rate = MAX11205B_OUT_DATA_RATE,
  96                 .name = "max11205b",
  97         },
  98 };
  99
 100 static void max11205_reg_disable(void *reg)
 101 {
 102         regulator_disable(reg);
 103 }
 104
 105 static int max11205_probe(struct spi_device *spi)
 106 {
 107         struct max11205_state *st;
 108         struct iio_dev *indio_dev;
 109         int ret;
 110
 111         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 112         if (!indio_dev)
 113                 return -ENOMEM;
 114
 115         st = iio_priv(indio_dev);
 116
 117         ad_sd_init(&st->sd, indio_dev, spi, &max11205_sigma_delta_info);
 118
 119         st->chip_info = spi_get_device_match_data(spi);
 120
 121         indio_dev->name = st->chip_info->name;
 122         indio_dev->modes = INDIO_DIRECT_MODE;
 123         indio_dev->channels = max11205_channels;
 124         indio_dev->num_channels = 1;
 125         indio_dev->info = &max11205_iio_info;
 126
 127         st->vref = devm_regulator_get(&spi->dev, "vref");
 128         if (IS_ERR(st->vref))
 129                 return dev_err_probe(&spi->dev, PTR_ERR(st->vref),
 130                                      "Failed to get vref regulator\n");
 131
 132         ret = regulator_enable(st->vref);
 133         if (ret)
 134                 return ret;
 135
 136         ret = devm_add_action_or_reset(&spi->dev, max11205_reg_disable, st->vref);
 137         if (ret)
 138                 return ret;
 139
 140         ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
 141         if (ret)
 142                 return ret;
 143
 144         return devm_iio_device_register(&spi->dev, indio_dev);
 145 }
 146
 147 static const struct spi_device_id max11205_spi_ids[] = {
 148         { "max11205a", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205A] },
 149         { "max11205b", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205B] },
 150         { }
 151 };
 152 MODULE_DEVICE_TABLE(spi, max11205_spi_ids);
 153
 154 static const struct of_device_id max11205_dt_ids[] = {
 155         {
 156                 .compatible = "maxim,max11205a",
 157                 .data = &max11205_chip_info[TYPE_MAX11205A],
 158         },
 159         {
 160                 .compatible = "maxim,max11205b",
 161                 .data = &max11205_chip_info[TYPE_MAX11205B],
 162         },
 163         { }
 164 };
 165 MODULE_DEVICE_TABLE(of, max11205_dt_ids);
 166
 167 static struct spi_driver max11205_spi_driver = {
 168         .driver = {
 169                 .name = "max11205",
 170                 .of_match_table = max11205_dt_ids,
 171         },
 172         .probe = max11205_probe,
 173         .id_table = max11205_spi_ids,
 174 };
 175 module_spi_driver(max11205_spi_driver);
 176
 177 MODULE_AUTHOR("Ramona Bolboaca <ramona.bolboaca@analog.com>");
 178 MODULE_DESCRIPTION("MAX11205 ADC driver");
 179 MODULE_LICENSE("GPL v2");
 180 MODULE_IMPORT_NS("IIO_AD_SIGMA_DELTA");