linux/drivers/iio/dac/ti-dac7311.c
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   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
  14enum {
  15        ID_DAC5311 = 0,
  16        ID_DAC6311,
  17        ID_DAC7311,
  18};
  19
  20enum {
  21        POWER_1KOHM_TO_GND = 0,
  22        POWER_100KOHM_TO_GND,
  23        POWER_TRI_STATE,
  24};
  25
  26struct ti_dac_spec {
  27        u8 resolution;
  28};
  29
  30static 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 */
  47struct 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
  58static 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
  66static 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
  75static const char * const ti_dac_powerdown_modes[] = {
  76        "1kohm_to_gnd",
  77        "100kohm_to_gnd",
  78        "three_state",
  79};
  80
  81static 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
  89static 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
  99static 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
 106static 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 sysfs_emit(buf, "%d\n", ti_dac->powerdown);
 114}
 115
 116static 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
 141static 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
 162static const struct iio_chan_spec ti_dac_channels[] = {
 163        TI_DAC_CHANNEL(0),
 164};
 165
 166static 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
 191static 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
 224static 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
 230static 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
 236static 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
 290err:
 291        mutex_destroy(&ti_dac->lock);
 292        regulator_disable(ti_dac->vref);
 293        return ret;
 294}
 295
 296static 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
 307static const struct of_device_id ti_dac_of_id[] = {
 308        { .compatible = "ti,dac5311" },
 309        { .compatible = "ti,dac6311" },
 310        { .compatible = "ti,dac7311" },
 311        { }
 312};
 313MODULE_DEVICE_TABLE(of, ti_dac_of_id);
 314
 315static const struct spi_device_id ti_dac_spi_id[] = {
 316        { "dac5311", ID_DAC5311  },
 317        { "dac6311", ID_DAC6311 },
 318        { "dac7311", ID_DAC7311 },
 319        { }
 320};
 321MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
 322
 323static 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};
 332module_spi_driver(ti_dac_driver);
 333
 334MODULE_AUTHOR("Charles-Antoine Couret <charles-antoine.couret@essensium.com>");
 335MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 1-channel DAC driver");
 336MODULE_LICENSE("GPL v2");
 337