drivers/iio/dac/ad5791.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * AD5760, AD5780, AD5781, AD5790, AD5791 Voltage Output Digital to Analog
   4  * Converter
   5  *
   6  * Copyright 2011 Analog Devices Inc.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/fs.h>
  11 #include <linux/device.h>
  12 #include <linux/kernel.h>
  13 #include <linux/spi/spi.h>
  14 #include <linux/slab.h>
  15 #include <linux/sysfs.h>
  16 #include <linux/regulator/consumer.h>
  17 #include <linux/module.h>
  18 #include <linux/bitops.h>
  19
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/sysfs.h>
  22 #include <linux/iio/dac/ad5791.h>
  23
  24 #define AD5791_DAC_MASK                 GENMASK(19, 0)
  25
  26 #define AD5791_CMD_READ                 BIT(23)
  27 #define AD5791_CMD_WRITE                0
  28 #define AD5791_ADDR(addr)               ((addr) << 20)
  29
  30 /* Registers */
  31 #define AD5791_ADDR_NOOP                0
  32 #define AD5791_ADDR_DAC0                1
  33 #define AD5791_ADDR_CTRL                2
  34 #define AD5791_ADDR_CLRCODE             3
  35 #define AD5791_ADDR_SW_CTRL             4
  36
  37 /* Control Register */
  38 #define AD5791_CTRL_RBUF                BIT(1)
  39 #define AD5791_CTRL_OPGND               BIT(2)
  40 #define AD5791_CTRL_DACTRI              BIT(3)
  41 #define AD5791_CTRL_BIN2SC              BIT(4)
  42 #define AD5791_CTRL_SDODIS              BIT(5)
  43 #define AD5761_CTRL_LINCOMP(x)          ((x) << 6)
  44
  45 #define AD5791_LINCOMP_0_10             0
  46 #define AD5791_LINCOMP_10_12            1
  47 #define AD5791_LINCOMP_12_16            2
  48 #define AD5791_LINCOMP_16_19            3
  49 #define AD5791_LINCOMP_19_20            12
  50
  51 #define AD5780_LINCOMP_0_10             0
  52 #define AD5780_LINCOMP_10_20            12
  53
  54 /* Software Control Register */
  55 #define AD5791_SWCTRL_LDAC              BIT(0)
  56 #define AD5791_SWCTRL_CLR               BIT(1)
  57 #define AD5791_SWCTRL_RESET             BIT(2)
  58
  59 #define AD5791_DAC_PWRDN_6K             0
  60 #define AD5791_DAC_PWRDN_3STATE         1
  61
  62 /**
  63  * struct ad5791_chip_info - chip specific information
  64  * @get_lin_comp:       function pointer to the device specific function
  65  */
  66
  67 struct ad5791_chip_info {
  68         int (*get_lin_comp)     (unsigned int span);
  69 };
  70
  71 /**
  72  * struct ad5791_state - driver instance specific data
  73  * @spi:                        spi_device
  74  * @reg_vdd:            positive supply regulator
  75  * @reg_vss:            negative supply regulator
  76  * @chip_info:          chip model specific constants
  77  * @vref_mv:            actual reference voltage used
  78  * @vref_neg_mv:        voltage of the negative supply
  79  * @ctrl:               control register cache
  80  * @pwr_down_mode:      current power down mode
  81  * @pwr_down:           true if device is powered down
  82  * @data:               spi transfer buffers
  83  */
  84 struct ad5791_state {
  85         struct spi_device               *spi;
  86         struct regulator                *reg_vdd;
  87         struct regulator                *reg_vss;
  88         const struct ad5791_chip_info   *chip_info;
  89         unsigned short                  vref_mv;
  90         unsigned int                    vref_neg_mv;
  91         unsigned                        ctrl;
  92         unsigned                        pwr_down_mode;
  93         bool                            pwr_down;
  94
  95         union {
  96                 __be32 d32;
  97                 u8 d8[4];
  98         } data[3] ____cacheline_aligned;
  99 };
 100
 101 enum ad5791_supported_device_ids {
 102         ID_AD5760,
 103         ID_AD5780,
 104         ID_AD5781,
 105         ID_AD5791,
 106 };
 107
 108 static int ad5791_spi_write(struct ad5791_state *st, u8 addr, u32 val)
 109 {
 110         st->data[0].d32 = cpu_to_be32(AD5791_CMD_WRITE |
 111                               AD5791_ADDR(addr) |
 112                               (val & AD5791_DAC_MASK));
 113
 114         return spi_write(st->spi, &st->data[0].d8[1], 3);
 115 }
 116
 117 static int ad5791_spi_read(struct ad5791_state *st, u8 addr, u32 *val)
 118 {
 119         int ret;
 120         struct spi_transfer xfers[] = {
 121                 {
 122                         .tx_buf = &st->data[0].d8[1],
 123                         .bits_per_word = 8,
 124                         .len = 3,
 125                         .cs_change = 1,
 126                 }, {
 127                         .tx_buf = &st->data[1].d8[1],
 128                         .rx_buf = &st->data[2].d8[1],
 129                         .bits_per_word = 8,
 130                         .len = 3,
 131                 },
 132         };
 133
 134         st->data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
 135                               AD5791_ADDR(addr));
 136         st->data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
 137
 138         ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
 139
 140         *val = be32_to_cpu(st->data[2].d32);
 141
 142         return ret;
 143 }
 144
 145 static const char * const ad5791_powerdown_modes[] = {
 146         "6kohm_to_gnd",
 147         "three_state",
 148 };
 149
 150 static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
 151         const struct iio_chan_spec *chan)
 152 {
 153         struct ad5791_state *st = iio_priv(indio_dev);
 154
 155         return st->pwr_down_mode;
 156 }
 157
 158 static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
 159         const struct iio_chan_spec *chan, unsigned int mode)
 160 {
 161         struct ad5791_state *st = iio_priv(indio_dev);
 162
 163         st->pwr_down_mode = mode;
 164
 165         return 0;
 166 }
 167
 168 static const struct iio_enum ad5791_powerdown_mode_enum = {
 169         .items = ad5791_powerdown_modes,
 170         .num_items = ARRAY_SIZE(ad5791_powerdown_modes),
 171         .get = ad5791_get_powerdown_mode,
 172         .set = ad5791_set_powerdown_mode,
 173 };
 174
 175 static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
 176         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 177 {
 178         struct ad5791_state *st = iio_priv(indio_dev);
 179
 180         return sysfs_emit(buf, "%d\n", st->pwr_down);
 181 }
 182
 183 static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
 184          uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 185          size_t len)
 186 {
 187         bool pwr_down;
 188         int ret;
 189         struct ad5791_state *st = iio_priv(indio_dev);
 190
 191         ret = strtobool(buf, &pwr_down);
 192         if (ret)
 193                 return ret;
 194
 195         if (!pwr_down) {
 196                 st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 197         } else {
 198                 if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
 199                         st->ctrl |= AD5791_CTRL_OPGND;
 200                 else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
 201                         st->ctrl |= AD5791_CTRL_DACTRI;
 202         }
 203         st->pwr_down = pwr_down;
 204
 205         ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl);
 206
 207         return ret ? ret : len;
 208 }
 209
 210 static int ad5791_get_lin_comp(unsigned int span)
 211 {
 212         if (span <= 10000)
 213                 return AD5791_LINCOMP_0_10;
 214         else if (span <= 12000)
 215                 return AD5791_LINCOMP_10_12;
 216         else if (span <= 16000)
 217                 return AD5791_LINCOMP_12_16;
 218         else if (span <= 19000)
 219                 return AD5791_LINCOMP_16_19;
 220         else
 221                 return AD5791_LINCOMP_19_20;
 222 }
 223
 224 static int ad5780_get_lin_comp(unsigned int span)
 225 {
 226         if (span <= 10000)
 227                 return AD5780_LINCOMP_0_10;
 228         else
 229                 return AD5780_LINCOMP_10_20;
 230 }
 231 static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
 232         [ID_AD5760] = {
 233                 .get_lin_comp = ad5780_get_lin_comp,
 234         },
 235         [ID_AD5780] = {
 236                 .get_lin_comp = ad5780_get_lin_comp,
 237         },
 238         [ID_AD5781] = {
 239                 .get_lin_comp = ad5791_get_lin_comp,
 240         },
 241         [ID_AD5791] = {
 242                 .get_lin_comp = ad5791_get_lin_comp,
 243         },
 244 };
 245
 246 static int ad5791_read_raw(struct iio_dev *indio_dev,
 247                            struct iio_chan_spec const *chan,
 248                            int *val,
 249                            int *val2,
 250                            long m)
 251 {
 252         struct ad5791_state *st = iio_priv(indio_dev);
 253         u64 val64;
 254         int ret;
 255
 256         switch (m) {
 257         case IIO_CHAN_INFO_RAW:
 258                 ret = ad5791_spi_read(st, chan->address, val);
 259                 if (ret)
 260                         return ret;
 261                 *val &= AD5791_DAC_MASK;
 262                 *val >>= chan->scan_type.shift;
 263                 return IIO_VAL_INT;
 264         case IIO_CHAN_INFO_SCALE:
 265                 *val = st->vref_mv;
 266                 *val2 = (1 << chan->scan_type.realbits) - 1;
 267                 return IIO_VAL_FRACTIONAL;
 268         case IIO_CHAN_INFO_OFFSET:
 269                 val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
 270                 do_div(val64, st->vref_mv);
 271                 *val = -val64;
 272                 return IIO_VAL_INT;
 273         default:
 274                 return -EINVAL;
 275         }
 276
 277 };
 278
 279 static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
 280         {
 281                 .name = "powerdown",
 282                 .shared = IIO_SHARED_BY_TYPE,
 283                 .read = ad5791_read_dac_powerdown,
 284                 .write = ad5791_write_dac_powerdown,
 285         },
 286         IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
 287                  &ad5791_powerdown_mode_enum),
 288         IIO_ENUM_AVAILABLE("powerdown_mode", &ad5791_powerdown_mode_enum),
 289         { },
 290 };
 291
 292 #define AD5791_CHAN(bits, _shift) {                     \
 293         .type = IIO_VOLTAGE,                            \
 294         .output = 1,                                    \
 295         .indexed = 1,                                   \
 296         .address = AD5791_ADDR_DAC0,                    \
 297         .channel = 0,                                   \
 298         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 299         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
 300                 BIT(IIO_CHAN_INFO_OFFSET),              \
 301         .scan_type = {                                  \
 302                 .sign = 'u',                            \
 303                 .realbits = (bits),                     \
 304                 .storagebits = 24,                      \
 305                 .shift = (_shift),                      \
 306         },                                              \
 307         .ext_info = ad5791_ext_info,                    \
 308 }
 309
 310 static const struct iio_chan_spec ad5791_channels[] = {
 311         [ID_AD5760] = AD5791_CHAN(16, 4),
 312         [ID_AD5780] = AD5791_CHAN(18, 2),
 313         [ID_AD5781] = AD5791_CHAN(18, 2),
 314         [ID_AD5791] = AD5791_CHAN(20, 0)
 315 };
 316
 317 static int ad5791_write_raw(struct iio_dev *indio_dev,
 318                             struct iio_chan_spec const *chan,
 319                             int val,
 320                             int val2,
 321                             long mask)
 322 {
 323         struct ad5791_state *st = iio_priv(indio_dev);
 324
 325         switch (mask) {
 326         case IIO_CHAN_INFO_RAW:
 327                 val &= GENMASK(chan->scan_type.realbits - 1, 0);
 328                 val <<= chan->scan_type.shift;
 329
 330                 return ad5791_spi_write(st, chan->address, val);
 331
 332         default:
 333                 return -EINVAL;
 334         }
 335 }
 336
 337 static const struct iio_info ad5791_info = {
 338         .read_raw = &ad5791_read_raw,
 339         .write_raw = &ad5791_write_raw,
 340 };
 341
 342 static int ad5791_probe(struct spi_device *spi)
 343 {
 344         struct ad5791_platform_data *pdata = spi->dev.platform_data;
 345         struct iio_dev *indio_dev;
 346         struct ad5791_state *st;
 347         int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
 348
 349         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 350         if (!indio_dev)
 351                 return -ENOMEM;
 352         st = iio_priv(indio_dev);
 353         st->reg_vdd = devm_regulator_get(&spi->dev, "vdd");
 354         if (!IS_ERR(st->reg_vdd)) {
 355                 ret = regulator_enable(st->reg_vdd);
 356                 if (ret)
 357                         return ret;
 358
 359                 ret = regulator_get_voltage(st->reg_vdd);
 360                 if (ret < 0)
 361                         goto error_disable_reg_pos;
 362
 363                 pos_voltage_uv = ret;
 364         }
 365
 366         st->reg_vss = devm_regulator_get(&spi->dev, "vss");
 367         if (!IS_ERR(st->reg_vss)) {
 368                 ret = regulator_enable(st->reg_vss);
 369                 if (ret)
 370                         goto error_disable_reg_pos;
 371
 372                 ret = regulator_get_voltage(st->reg_vss);
 373                 if (ret < 0)
 374                         goto error_disable_reg_neg;
 375
 376                 neg_voltage_uv = ret;
 377         }
 378
 379         st->pwr_down = true;
 380         st->spi = spi;
 381
 382         if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd)) {
 383                 st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
 384                 st->vref_neg_mv = neg_voltage_uv / 1000;
 385         } else if (pdata) {
 386                 st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
 387                 st->vref_neg_mv = pdata->vref_neg_mv;
 388         } else {
 389                 dev_warn(&spi->dev, "reference voltage unspecified\n");
 390         }
 391
 392         ret = ad5791_spi_write(st, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
 393         if (ret)
 394                 goto error_disable_reg_neg;
 395
 396         st->chip_info = &ad5791_chip_info_tbl[spi_get_device_id(spi)
 397                                               ->driver_data];
 398
 399
 400         st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
 401                   | ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
 402                   AD5791_CTRL_BIN2SC;
 403
 404         ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl |
 405                 AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 406         if (ret)
 407                 goto error_disable_reg_neg;
 408
 409         spi_set_drvdata(spi, indio_dev);
 410         indio_dev->info = &ad5791_info;
 411         indio_dev->modes = INDIO_DIRECT_MODE;
 412         indio_dev->channels
 413                 = &ad5791_channels[spi_get_device_id(spi)->driver_data];
 414         indio_dev->num_channels = 1;
 415         indio_dev->name = spi_get_device_id(st->spi)->name;
 416         ret = iio_device_register(indio_dev);
 417         if (ret)
 418                 goto error_disable_reg_neg;
 419
 420         return 0;
 421
 422 error_disable_reg_neg:
 423         if (!IS_ERR(st->reg_vss))
 424                 regulator_disable(st->reg_vss);
 425 error_disable_reg_pos:
 426         if (!IS_ERR(st->reg_vdd))
 427                 regulator_disable(st->reg_vdd);
 428         return ret;
 429 }
 430
 431 static int ad5791_remove(struct spi_device *spi)
 432 {
 433         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 434         struct ad5791_state *st = iio_priv(indio_dev);
 435
 436         iio_device_unregister(indio_dev);
 437         if (!IS_ERR(st->reg_vdd))
 438                 regulator_disable(st->reg_vdd);
 439
 440         if (!IS_ERR(st->reg_vss))
 441                 regulator_disable(st->reg_vss);
 442
 443         return 0;
 444 }
 445
 446 static const struct spi_device_id ad5791_id[] = {
 447         {"ad5760", ID_AD5760},
 448         {"ad5780", ID_AD5780},
 449         {"ad5781", ID_AD5781},
 450         {"ad5790", ID_AD5791},
 451         {"ad5791", ID_AD5791},
 452         {}
 453 };
 454 MODULE_DEVICE_TABLE(spi, ad5791_id);
 455
 456 static struct spi_driver ad5791_driver = {
 457         .driver = {
 458                    .name = "ad5791",
 459                    },
 460         .probe = ad5791_probe,
 461         .remove = ad5791_remove,
 462         .id_table = ad5791_id,
 463 };
 464 module_spi_driver(ad5791_driver);
 465
 466 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
 467 MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
 468 MODULE_LICENSE("GPL v2");