drivers/iio/dac/ti-dac082s085.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ti-dac082s085.c - Texas Instruments 8/10/12-bit 2/4-channel DAC driver
   4  *
   5  * Copyright (C) 2017 KUNBUS GmbH
   6  *
   7  * https://www.ti.com/lit/ds/symlink/dac082s085.pdf
   8  * https://www.ti.com/lit/ds/symlink/dac102s085.pdf
   9  * https://www.ti.com/lit/ds/symlink/dac122s085.pdf
  10  * https://www.ti.com/lit/ds/symlink/dac084s085.pdf
  11  * https://www.ti.com/lit/ds/symlink/dac104s085.pdf
  12  * https://www.ti.com/lit/ds/symlink/dac124s085.pdf
  13  */
  14
  15 #include <linux/iio/iio.h>
  16 #include <linux/module.h>
  17 #include <linux/mod_devicetable.h>
  18 #include <linux/regulator/consumer.h>
  19 #include <linux/spi/spi.h>
  20
  21 enum { dual_8bit, dual_10bit, dual_12bit, quad_8bit, quad_10bit, quad_12bit };
  22
  23 struct ti_dac_spec {
  24         u8 num_channels;
  25         u8 resolution;
  26 };
  27
  28 static const struct ti_dac_spec ti_dac_spec[] = {
  29         [dual_8bit]  = { .num_channels = 2, .resolution = 8  },
  30         [dual_10bit] = { .num_channels = 2, .resolution = 10 },
  31         [dual_12bit] = { .num_channels = 2, .resolution = 12 },
  32         [quad_8bit]  = { .num_channels = 4, .resolution = 8  },
  33         [quad_10bit] = { .num_channels = 4, .resolution = 10 },
  34         [quad_12bit] = { .num_channels = 4, .resolution = 12 },
  35 };
  36
  37 /**
  38  * struct ti_dac_chip - TI DAC chip
  39  * @lock: protects write sequences
  40  * @vref: regulator generating Vref
  41  * @mesg: SPI message to perform a write
  42  * @xfer: SPI transfer used by @mesg
  43  * @val: cached value of each output
  44  * @powerdown: whether the chip is powered down
  45  * @powerdown_mode: selected by the user
  46  * @resolution: resolution of the chip
  47  * @buf: buffer for @xfer
  48  */
  49 struct ti_dac_chip {
  50         struct mutex lock;
  51         struct regulator *vref;
  52         struct spi_message mesg;
  53         struct spi_transfer xfer;
  54         u16 val[4];
  55         bool powerdown;
  56         u8 powerdown_mode;
  57         u8 resolution;
  58         u8 buf[2] ____cacheline_aligned;
  59 };
  60
  61 #define WRITE_NOT_UPDATE(chan)  (0x00 | (chan) << 6)
  62 #define WRITE_AND_UPDATE(chan)  (0x10 | (chan) << 6)
  63 #define WRITE_ALL_UPDATE         0x20
  64 #define POWERDOWN(mode)         (0x30 | ((mode) + 1) << 6)
  65
  66 static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 cmd, u16 val)
  67 {
  68         u8 shift = 12 - ti_dac->resolution;
  69
  70         ti_dac->buf[0] = cmd | (val >> (8 - shift));
  71         ti_dac->buf[1] = (val << shift) & 0xff;
  72         return spi_sync(ti_dac->mesg.spi, &ti_dac->mesg);
  73 }
  74
  75 static const char * const ti_dac_powerdown_modes[] = {
  76         "2.5kohm_to_gnd", "100kohm_to_gnd", "three_state",
  77 };
  78
  79 static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
  80                                      const struct iio_chan_spec *chan)
  81 {
  82         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
  83
  84         return ti_dac->powerdown_mode;
  85 }
  86
  87 static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
  88                                      const struct iio_chan_spec *chan,
  89                                      unsigned int mode)
  90 {
  91         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
  92         int ret = 0;
  93
  94         if (ti_dac->powerdown_mode == mode)
  95                 return 0;
  96
  97         mutex_lock(&ti_dac->lock);
  98         if (ti_dac->powerdown) {
  99                 ret = ti_dac_cmd(ti_dac, POWERDOWN(mode), 0);
 100                 if (ret)
 101                         goto out;
 102         }
 103         ti_dac->powerdown_mode = mode;
 104
 105 out:
 106         mutex_unlock(&ti_dac->lock);
 107         return ret;
 108 }
 109
 110 static const struct iio_enum ti_dac_powerdown_mode = {
 111         .items = ti_dac_powerdown_modes,
 112         .num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
 113         .get = ti_dac_get_powerdown_mode,
 114         .set = ti_dac_set_powerdown_mode,
 115 };
 116
 117 static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
 118                                      uintptr_t private,
 119                                      const struct iio_chan_spec *chan,
 120                                      char *buf)
 121 {
 122         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 123
 124         return sysfs_emit(buf, "%d\n", ti_dac->powerdown);
 125 }
 126
 127 static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
 128                                       uintptr_t private,
 129                                       const struct iio_chan_spec *chan,
 130                                       const char *buf, size_t len)
 131 {
 132         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 133         bool powerdown;
 134         int ret;
 135
 136         ret = strtobool(buf, &powerdown);
 137         if (ret)
 138                 return ret;
 139
 140         if (ti_dac->powerdown == powerdown)
 141                 return len;
 142
 143         mutex_lock(&ti_dac->lock);
 144         if (powerdown)
 145                 ret = ti_dac_cmd(ti_dac, POWERDOWN(ti_dac->powerdown_mode), 0);
 146         else
 147                 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(0), ti_dac->val[0]);
 148         if (!ret)
 149                 ti_dac->powerdown = powerdown;
 150         mutex_unlock(&ti_dac->lock);
 151
 152         return ret ? ret : len;
 153 }
 154
 155 static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
 156         {
 157                 .name      = "powerdown",
 158                 .read      = ti_dac_read_powerdown,
 159                 .write     = ti_dac_write_powerdown,
 160                 .shared    = IIO_SHARED_BY_TYPE,
 161         },
 162         IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
 163         IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode),
 164         { },
 165 };
 166
 167 #define TI_DAC_CHANNEL(chan) {                                  \
 168         .type = IIO_VOLTAGE,                                    \
 169         .channel = (chan),                                      \
 170         .address = (chan),                                      \
 171         .indexed = true,                                        \
 172         .output = true,                                         \
 173         .datasheet_name = (const char[]){ 'A' + (chan), 0 },    \
 174         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 175         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 176         .ext_info = ti_dac_ext_info,                            \
 177 }
 178
 179 static const struct iio_chan_spec ti_dac_channels[] = {
 180         TI_DAC_CHANNEL(0),
 181         TI_DAC_CHANNEL(1),
 182         TI_DAC_CHANNEL(2),
 183         TI_DAC_CHANNEL(3),
 184 };
 185
 186 static int ti_dac_read_raw(struct iio_dev *indio_dev,
 187                            struct iio_chan_spec const *chan,
 188                            int *val, int *val2, long mask)
 189 {
 190         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 191         int ret;
 192
 193         switch (mask) {
 194         case IIO_CHAN_INFO_RAW:
 195                 *val = ti_dac->val[chan->channel];
 196                 ret = IIO_VAL_INT;
 197                 break;
 198
 199         case IIO_CHAN_INFO_SCALE:
 200                 ret = regulator_get_voltage(ti_dac->vref);
 201                 if (ret < 0)
 202                         return ret;
 203
 204                 *val = ret / 1000;
 205                 *val2 = ti_dac->resolution;
 206                 ret = IIO_VAL_FRACTIONAL_LOG2;
 207                 break;
 208
 209         default:
 210                 ret = -EINVAL;
 211         }
 212
 213         return ret;
 214 }
 215
 216 static int ti_dac_write_raw(struct iio_dev *indio_dev,
 217                             struct iio_chan_spec const *chan,
 218                             int val, int val2, long mask)
 219 {
 220         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 221         int ret;
 222
 223         switch (mask) {
 224         case IIO_CHAN_INFO_RAW:
 225                 if (ti_dac->val[chan->channel] == val)
 226                         return 0;
 227
 228                 if (val >= (1 << ti_dac->resolution) || val < 0)
 229                         return -EINVAL;
 230
 231                 if (ti_dac->powerdown)
 232                         return -EBUSY;
 233
 234                 mutex_lock(&ti_dac->lock);
 235                 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(chan->channel), val);
 236                 if (!ret)
 237                         ti_dac->val[chan->channel] = val;
 238                 mutex_unlock(&ti_dac->lock);
 239                 break;
 240
 241         default:
 242                 ret = -EINVAL;
 243         }
 244
 245         return ret;
 246 }
 247
 248 static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
 249                                     struct iio_chan_spec const *chan, long mask)
 250 {
 251         return IIO_VAL_INT;
 252 }
 253
 254 static const struct iio_info ti_dac_info = {
 255         .read_raw          = ti_dac_read_raw,
 256         .write_raw         = ti_dac_write_raw,
 257         .write_raw_get_fmt = ti_dac_write_raw_get_fmt,
 258 };
 259
 260 static int ti_dac_probe(struct spi_device *spi)
 261 {
 262         struct device *dev = &spi->dev;
 263         const struct ti_dac_spec *spec;
 264         struct ti_dac_chip *ti_dac;
 265         struct iio_dev *indio_dev;
 266         int ret;
 267
 268         indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
 269         if (!indio_dev)
 270                 return -ENOMEM;
 271
 272         indio_dev->info = &ti_dac_info;
 273         indio_dev->name = spi->modalias;
 274         indio_dev->modes = INDIO_DIRECT_MODE;
 275         indio_dev->channels = ti_dac_channels;
 276         spi_set_drvdata(spi, indio_dev);
 277
 278         ti_dac = iio_priv(indio_dev);
 279         ti_dac->xfer.tx_buf = &ti_dac->buf;
 280         ti_dac->xfer.len = sizeof(ti_dac->buf);
 281         spi_message_init_with_transfers(&ti_dac->mesg, &ti_dac->xfer, 1);
 282         ti_dac->mesg.spi = spi;
 283
 284         spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
 285         indio_dev->num_channels = spec->num_channels;
 286         ti_dac->resolution = spec->resolution;
 287
 288         ti_dac->vref = devm_regulator_get(dev, "vref");
 289         if (IS_ERR(ti_dac->vref))
 290                 return PTR_ERR(ti_dac->vref);
 291
 292         ret = regulator_enable(ti_dac->vref);
 293         if (ret < 0)
 294                 return ret;
 295
 296         mutex_init(&ti_dac->lock);
 297
 298         ret = ti_dac_cmd(ti_dac, WRITE_ALL_UPDATE, 0);
 299         if (ret) {
 300                 dev_err(dev, "failed to initialize outputs to 0\n");
 301                 goto err;
 302         }
 303
 304         ret = iio_device_register(indio_dev);
 305         if (ret)
 306                 goto err;
 307
 308         return 0;
 309
 310 err:
 311         mutex_destroy(&ti_dac->lock);
 312         regulator_disable(ti_dac->vref);
 313         return ret;
 314 }
 315
 316 static int ti_dac_remove(struct spi_device *spi)
 317 {
 318         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 319         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 320
 321         iio_device_unregister(indio_dev);
 322         mutex_destroy(&ti_dac->lock);
 323         regulator_disable(ti_dac->vref);
 324
 325         return 0;
 326 }
 327
 328 static const struct of_device_id ti_dac_of_id[] = {
 329         { .compatible = "ti,dac082s085" },
 330         { .compatible = "ti,dac102s085" },
 331         { .compatible = "ti,dac122s085" },
 332         { .compatible = "ti,dac084s085" },
 333         { .compatible = "ti,dac104s085" },
 334         { .compatible = "ti,dac124s085" },
 335         { }
 336 };
 337 MODULE_DEVICE_TABLE(of, ti_dac_of_id);
 338
 339 static const struct spi_device_id ti_dac_spi_id[] = {
 340         { "dac082s085", dual_8bit  },
 341         { "dac102s085", dual_10bit },
 342         { "dac122s085", dual_12bit },
 343         { "dac084s085", quad_8bit  },
 344         { "dac104s085", quad_10bit },
 345         { "dac124s085", quad_12bit },
 346         { }
 347 };
 348 MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
 349
 350 static struct spi_driver ti_dac_driver = {
 351         .driver = {
 352                 .name           = "ti-dac082s085",
 353                 .of_match_table = ti_dac_of_id,
 354         },
 355         .probe    = ti_dac_probe,
 356         .remove   = ti_dac_remove,
 357         .id_table = ti_dac_spi_id,
 358 };
 359 module_spi_driver(ti_dac_driver);
 360
 361 MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
 362 MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 2/4-channel DAC driver");
 363 MODULE_LICENSE("GPL v2");