drivers/iio/dac/ti-dac7311.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* ti-dac7311.c - Texas Instruments 8/10/12-bit 1-channel DAC driver
   3  *
   4  * Copyright (C) 2018 CMC NV
   5  *
   6  * https://www.ti.com/lit/ds/symlink/dac7311.pdf
   7  */
   8
   9 #include <linux/iio/iio.h>
  10 #include <linux/module.h>
  11 #include <linux/regulator/consumer.h>
  12 #include <linux/spi/spi.h>
  13
  14 enum {
  15         ID_DAC5311 = 0,
  16         ID_DAC6311,
  17         ID_DAC7311,
  18 };
  19
  20 enum {
  21         POWER_1KOHM_TO_GND = 0,
  22         POWER_100KOHM_TO_GND,
  23         POWER_TRI_STATE,
  24 };
  25
  26 struct ti_dac_spec {
  27         u8 resolution;
  28 };
  29
  30 static const struct ti_dac_spec ti_dac_spec[] = {
  31         [ID_DAC5311] = { .resolution = 8 },
  32         [ID_DAC6311] = { .resolution = 10 },
  33         [ID_DAC7311] = { .resolution = 12 },
  34 };
  35
  36 /**
  37  * struct ti_dac_chip - TI DAC chip
  38  * @lock: protects write sequences
  39  * @vref: regulator generating Vref
  40  * @spi: SPI device to send data to the device
  41  * @val: cached value
  42  * @powerdown: whether the chip is powered down
  43  * @powerdown_mode: selected by the user
  44  * @resolution: resolution of the chip
  45  * @buf: buffer for transfer data
  46  */
  47 struct ti_dac_chip {
  48         struct mutex lock;
  49         struct regulator *vref;
  50         struct spi_device *spi;
  51         u16 val;
  52         bool powerdown;
  53         u8 powerdown_mode;
  54         u8 resolution;
  55         u8 buf[2] ____cacheline_aligned;
  56 };
  57
  58 static u8 ti_dac_get_power(struct ti_dac_chip *ti_dac, bool powerdown)
  59 {
  60         if (powerdown)
  61                 return ti_dac->powerdown_mode + 1;
  62
  63         return 0;
  64 }
  65
  66 static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 power, u16 val)
  67 {
  68         u8 shift = 14 - ti_dac->resolution;
  69
  70         ti_dac->buf[0] = (val << shift) & 0xFF;
  71         ti_dac->buf[1] = (power << 6) | (val >> (8 - shift));
  72         return spi_write(ti_dac->spi, ti_dac->buf, 2);
  73 }
  74
  75 static const char * const ti_dac_powerdown_modes[] = {
  76         "1kohm_to_gnd",
  77         "100kohm_to_gnd",
  78         "three_state",
  79 };
  80
  81 static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
  82                                      const struct iio_chan_spec *chan)
  83 {
  84         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
  85
  86         return ti_dac->powerdown_mode;
  87 }
  88
  89 static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
  90                                      const struct iio_chan_spec *chan,
  91                                      unsigned int mode)
  92 {
  93         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
  94
  95         ti_dac->powerdown_mode = mode;
  96         return 0;
  97 }
  98
  99 static const struct iio_enum ti_dac_powerdown_mode = {
 100         .items = ti_dac_powerdown_modes,
 101         .num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
 102         .get = ti_dac_get_powerdown_mode,
 103         .set = ti_dac_set_powerdown_mode,
 104 };
 105
 106 static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
 107                                      uintptr_t private,
 108                                      const struct iio_chan_spec *chan,
 109                                      char *buf)
 110 {
 111         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 112
 113         return sprintf(buf, "%d\n", ti_dac->powerdown);
 114 }
 115
 116 static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
 117                                       uintptr_t private,
 118                                       const struct iio_chan_spec *chan,
 119                                       const char *buf, size_t len)
 120 {
 121         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 122         bool powerdown;
 123         u8 power;
 124         int ret;
 125
 126         ret = strtobool(buf, &powerdown);
 127         if (ret)
 128                 return ret;
 129
 130         power = ti_dac_get_power(ti_dac, powerdown);
 131
 132         mutex_lock(&ti_dac->lock);
 133         ret = ti_dac_cmd(ti_dac, power, 0);
 134         if (!ret)
 135                 ti_dac->powerdown = powerdown;
 136         mutex_unlock(&ti_dac->lock);
 137
 138         return ret ? ret : len;
 139 }
 140
 141 static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
 142         {
 143                 .name      = "powerdown",
 144                 .read      = ti_dac_read_powerdown,
 145                 .write     = ti_dac_write_powerdown,
 146                 .shared    = IIO_SHARED_BY_TYPE,
 147         },
 148         IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
 149         IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode),
 150         { },
 151 };
 152
 153 #define TI_DAC_CHANNEL(chan) {                                  \
 154         .type = IIO_VOLTAGE,                                    \
 155         .channel = (chan),                                      \
 156         .output = true,                                         \
 157         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 158         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 159         .ext_info = ti_dac_ext_info,                            \
 160 }
 161
 162 static const struct iio_chan_spec ti_dac_channels[] = {
 163         TI_DAC_CHANNEL(0),
 164 };
 165
 166 static int ti_dac_read_raw(struct iio_dev *indio_dev,
 167                            struct iio_chan_spec const *chan,
 168                            int *val, int *val2, long mask)
 169 {
 170         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 171         int ret;
 172
 173         switch (mask) {
 174         case IIO_CHAN_INFO_RAW:
 175                 *val = ti_dac->val;
 176                 return IIO_VAL_INT;
 177
 178         case IIO_CHAN_INFO_SCALE:
 179                 ret = regulator_get_voltage(ti_dac->vref);
 180                 if (ret < 0)
 181                         return ret;
 182
 183                 *val = ret / 1000;
 184                 *val2 = ti_dac->resolution;
 185                 return IIO_VAL_FRACTIONAL_LOG2;
 186         }
 187
 188         return -EINVAL;
 189 }
 190
 191 static int ti_dac_write_raw(struct iio_dev *indio_dev,
 192                             struct iio_chan_spec const *chan,
 193                             int val, int val2, long mask)
 194 {
 195         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 196         u8 power = ti_dac_get_power(ti_dac, ti_dac->powerdown);
 197         int ret;
 198
 199         switch (mask) {
 200         case IIO_CHAN_INFO_RAW:
 201                 if (ti_dac->val == val)
 202                         return 0;
 203
 204                 if (val >= (1 << ti_dac->resolution) || val < 0)
 205                         return -EINVAL;
 206
 207                 if (ti_dac->powerdown)
 208                         return -EBUSY;
 209
 210                 mutex_lock(&ti_dac->lock);
 211                 ret = ti_dac_cmd(ti_dac, power, val);
 212                 if (!ret)
 213                         ti_dac->val = val;
 214                 mutex_unlock(&ti_dac->lock);
 215                 break;
 216
 217         default:
 218                 ret = -EINVAL;
 219         }
 220
 221         return ret;
 222 }
 223
 224 static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
 225                                     struct iio_chan_spec const *chan, long mask)
 226 {
 227         return IIO_VAL_INT;
 228 }
 229
 230 static const struct iio_info ti_dac_info = {
 231         .read_raw          = ti_dac_read_raw,
 232         .write_raw         = ti_dac_write_raw,
 233         .write_raw_get_fmt = ti_dac_write_raw_get_fmt,
 234 };
 235
 236 static int ti_dac_probe(struct spi_device *spi)
 237 {
 238         struct device *dev = &spi->dev;
 239         const struct ti_dac_spec *spec;
 240         struct ti_dac_chip *ti_dac;
 241         struct iio_dev *indio_dev;
 242         int ret;
 243
 244         indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
 245         if (!indio_dev) {
 246                 dev_err(dev, "can not allocate iio device\n");
 247                 return -ENOMEM;
 248         }
 249
 250         spi->mode = SPI_MODE_1;
 251         spi->bits_per_word = 16;
 252         spi_setup(spi);
 253
 254         indio_dev->info = &ti_dac_info;
 255         indio_dev->name = spi_get_device_id(spi)->name;
 256         indio_dev->modes = INDIO_DIRECT_MODE;
 257         indio_dev->channels = ti_dac_channels;
 258         spi_set_drvdata(spi, indio_dev);
 259
 260         ti_dac = iio_priv(indio_dev);
 261         ti_dac->powerdown = false;
 262         ti_dac->spi = spi;
 263
 264         spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
 265         indio_dev->num_channels = 1;
 266         ti_dac->resolution = spec->resolution;
 267
 268         ti_dac->vref = devm_regulator_get(dev, "vref");
 269         if (IS_ERR(ti_dac->vref)) {
 270                 dev_err(dev, "error to get regulator\n");
 271                 return PTR_ERR(ti_dac->vref);
 272         }
 273
 274         ret = regulator_enable(ti_dac->vref);
 275         if (ret < 0) {
 276                 dev_err(dev, "can not enable regulator\n");
 277                 return ret;
 278         }
 279
 280         mutex_init(&ti_dac->lock);
 281
 282         ret = iio_device_register(indio_dev);
 283         if (ret) {
 284                 dev_err(dev, "fail to register iio device: %d\n", ret);
 285                 goto err;
 286         }
 287
 288         return 0;
 289
 290 err:
 291         mutex_destroy(&ti_dac->lock);
 292         regulator_disable(ti_dac->vref);
 293         return ret;
 294 }
 295
 296 static int ti_dac_remove(struct spi_device *spi)
 297 {
 298         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 299         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 300
 301         iio_device_unregister(indio_dev);
 302         mutex_destroy(&ti_dac->lock);
 303         regulator_disable(ti_dac->vref);
 304         return 0;
 305 }
 306
 307 static const struct of_device_id ti_dac_of_id[] = {
 308         { .compatible = "ti,dac5311" },
 309         { .compatible = "ti,dac6311" },
 310         { .compatible = "ti,dac7311" },
 311         { }
 312 };
 313 MODULE_DEVICE_TABLE(of, ti_dac_of_id);
 314
 315 static const struct spi_device_id ti_dac_spi_id[] = {
 316         { "dac5311", ID_DAC5311  },
 317         { "dac6311", ID_DAC6311 },
 318         { "dac7311", ID_DAC7311 },
 319         { }
 320 };
 321 MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
 322
 323 static struct spi_driver ti_dac_driver = {
 324         .driver = {
 325                 .name           = "ti-dac7311",
 326                 .of_match_table = ti_dac_of_id,
 327         },
 328         .probe    = ti_dac_probe,
 329         .remove   = ti_dac_remove,
 330         .id_table = ti_dac_spi_id,
 331 };
 332 module_spi_driver(ti_dac_driver);
 333
 334 MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
 335 MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 1-channel DAC driver");
 336 MODULE_LICENSE("GPL v2");