drivers/iio/dac/max5522.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Maxim MAX5522
   4  * Dual, Ultra-Low-Power 10-Bit, Voltage-Output DACs
   5  *
   6  * Copyright 2022 Timesys Corp.
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/mod_devicetable.h>
  13 #include <linux/regmap.h>
  14 #include <linux/regulator/consumer.h>
  15 #include <linux/slab.h>
  16 #include <linux/spi/spi.h>
  17
  18 #include <linux/iio/iio.h>
  19
  20 #define MAX5522_MAX_ADDR        15
  21 #define MAX5522_CTRL_NONE       0
  22 #define MAX5522_CTRL_LOAD_IN_A  9
  23 #define MAX5522_CTRL_LOAD_IN_B  10
  24
  25 #define MAX5522_REG_DATA(x)     ((x) + MAX5522_CTRL_LOAD_IN_A)
  26
  27 struct max5522_chip_info {
  28         const char *name;
  29         const struct iio_chan_spec *channels;
  30         unsigned int num_channels;
  31 };
  32
  33 struct max5522_state {
  34         struct regmap *regmap;
  35         const struct max5522_chip_info *chip_info;
  36         unsigned short dac_cache[2];
  37         struct regulator *vrefin_reg;
  38 };
  39
  40 #define MAX5522_CHANNEL(chan) { \
  41         .type = IIO_VOLTAGE, \
  42         .indexed = 1, \
  43         .output = 1, \
  44         .channel = chan, \
  45         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
  46                               BIT(IIO_CHAN_INFO_SCALE), \
  47         .scan_type = { \
  48                 .sign = 'u', \
  49                 .realbits = 10, \
  50                 .storagebits = 16, \
  51                 .shift = 2, \
  52         } \
  53 }
  54
  55 static const struct iio_chan_spec max5522_channels[] = {
  56         MAX5522_CHANNEL(0),
  57         MAX5522_CHANNEL(1),
  58 };
  59
  60 enum max5522_type {
  61         ID_MAX5522,
  62 };
  63
  64 static const struct max5522_chip_info max5522_chip_info_tbl[] = {
  65         [ID_MAX5522] = {
  66                 .name = "max5522",
  67                 .channels = max5522_channels,
  68                 .num_channels = 2,
  69         },
  70 };
  71
  72 static inline int max5522_info_to_reg(struct iio_chan_spec const *chan)
  73 {
  74         return MAX5522_REG_DATA(chan->channel);
  75 }
  76
  77 static int max5522_read_raw(struct iio_dev *indio_dev,
  78                             struct iio_chan_spec const *chan,
  79                             int *val, int *val2, long info)
  80 {
  81         struct max5522_state *state = iio_priv(indio_dev);
  82         int ret;
  83
  84         switch (info) {
  85         case IIO_CHAN_INFO_RAW:
  86                 *val = state->dac_cache[chan->channel];
  87                 return IIO_VAL_INT;
  88         case IIO_CHAN_INFO_SCALE:
  89                 ret = regulator_get_voltage(state->vrefin_reg);
  90                 if (ret < 0)
  91                         return -EINVAL;
  92                 *val = ret / 1000;
  93                 *val2 = 10;
  94                 return IIO_VAL_FRACTIONAL_LOG2;
  95         default:
  96                 return -EINVAL;
  97         }
  98
  99         return -EINVAL;
 100 }
 101
 102 static int max5522_write_raw(struct iio_dev *indio_dev,
 103                              struct iio_chan_spec const *chan,
 104                              int val, int val2, long info)
 105 {
 106         struct max5522_state *state = iio_priv(indio_dev);
 107         int rval;
 108
 109         if (val > 1023 || val < 0)
 110                 return -EINVAL;
 111
 112         rval = regmap_write(state->regmap, max5522_info_to_reg(chan),
 113                             val << chan->scan_type.shift);
 114         if (rval < 0)
 115                 return rval;
 116
 117         state->dac_cache[chan->channel] = val;
 118
 119         return 0;
 120 }
 121
 122 static const struct iio_info max5522_info = {
 123         .read_raw = max5522_read_raw,
 124         .write_raw = max5522_write_raw,
 125 };
 126
 127 static const struct regmap_config max5522_regmap_config = {
 128         .reg_bits = 4,
 129         .val_bits = 12,
 130         .max_register = MAX5522_MAX_ADDR,
 131 };
 132
 133 static int max5522_spi_probe(struct spi_device *spi)
 134 {
 135         struct iio_dev *indio_dev;
 136         struct max5522_state *state;
 137         int ret;
 138
 139         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
 140         if (indio_dev == NULL) {
 141                 dev_err(&spi->dev, "failed to allocate iio device\n");
 142                 return  -ENOMEM;
 143         }
 144
 145         state = iio_priv(indio_dev);
 146         state->chip_info = spi_get_device_match_data(spi);
 147         if (!state->chip_info)
 148                 return -EINVAL;
 149
 150         state->vrefin_reg = devm_regulator_get(&spi->dev, "vrefin");
 151         if (IS_ERR(state->vrefin_reg))
 152                 return dev_err_probe(&spi->dev, PTR_ERR(state->vrefin_reg),
 153                                      "Vrefin regulator not specified\n");
 154
 155         ret = regulator_enable(state->vrefin_reg);
 156         if (ret) {
 157                 return dev_err_probe(&spi->dev, ret,
 158                                      "Failed to enable vref regulators\n");
 159         }
 160
 161         state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config);
 162
 163         if (IS_ERR(state->regmap))
 164                 return PTR_ERR(state->regmap);
 165
 166         indio_dev->info = &max5522_info;
 167         indio_dev->modes = INDIO_DIRECT_MODE;
 168         indio_dev->channels = max5522_channels;
 169         indio_dev->num_channels = ARRAY_SIZE(max5522_channels);
 170         indio_dev->name = max5522_chip_info_tbl[ID_MAX5522].name;
 171
 172         return devm_iio_device_register(&spi->dev, indio_dev);
 173 }
 174
 175 static const struct spi_device_id max5522_ids[] = {
 176         { "max5522", (kernel_ulong_t)&max5522_chip_info_tbl[ID_MAX5522] },
 177         {}
 178 };
 179 MODULE_DEVICE_TABLE(spi, max5522_ids);
 180
 181 static const struct of_device_id max5522_of_match[] = {
 182         {
 183                 .compatible = "maxim,max5522",
 184                 .data = &max5522_chip_info_tbl[ID_MAX5522],
 185         },
 186         {}
 187 };
 188 MODULE_DEVICE_TABLE(of, max5522_of_match);
 189
 190 static struct spi_driver max5522_spi_driver = {
 191         .driver = {
 192                 .name = "max5522",
 193                 .of_match_table = max5522_of_match,
 194         },
 195         .probe = max5522_spi_probe,
 196         .id_table = max5522_ids,
 197 };
 198 module_spi_driver(max5522_spi_driver);
 199
 200 MODULE_AUTHOR("Angelo Dureghello <[email protected]");
 201 MODULE_DESCRIPTION("MAX5522 DAC driver");
 202 MODULE_LICENSE("GPL");