drivers/iio/dac/ad5791.c

   1 /*
   2  * AD5760, AD5780, AD5781, AD5790, AD5791 Voltage Output Digital to Analog
   3  * Converter
   4  *
   5  * Copyright 2011 Analog Devices Inc.
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/fs.h>
  12 #include <linux/device.h>
  13 #include <linux/kernel.h>
  14 #include <linux/spi/spi.h>
  15 #include <linux/slab.h>
  16 #include <linux/sysfs.h>
  17 #include <linux/regulator/consumer.h>
  18 #include <linux/module.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_RES_MASK(x)              ((1 << (x)) - 1)
  25 #define AD5791_DAC_MASK                 AD5791_RES_MASK(20)
  26 #define AD5791_DAC_MSB                  (1 << 19)
  27
  28 #define AD5791_CMD_READ                 (1 << 23)
  29 #define AD5791_CMD_WRITE                (0 << 23)
  30 #define AD5791_ADDR(addr)               ((addr) << 20)
  31
  32 /* Registers */
  33 #define AD5791_ADDR_NOOP                0
  34 #define AD5791_ADDR_DAC0                1
  35 #define AD5791_ADDR_CTRL                2
  36 #define AD5791_ADDR_CLRCODE             3
  37 #define AD5791_ADDR_SW_CTRL             4
  38
  39 /* Control Register */
  40 #define AD5791_CTRL_RBUF                (1 << 1)
  41 #define AD5791_CTRL_OPGND               (1 << 2)
  42 #define AD5791_CTRL_DACTRI              (1 << 3)
  43 #define AD5791_CTRL_BIN2SC              (1 << 4)
  44 #define AD5791_CTRL_SDODIS              (1 << 5)
  45 #define AD5761_CTRL_LINCOMP(x)          ((x) << 6)
  46
  47 #define AD5791_LINCOMP_0_10             0
  48 #define AD5791_LINCOMP_10_12            1
  49 #define AD5791_LINCOMP_12_16            2
  50 #define AD5791_LINCOMP_16_19            3
  51 #define AD5791_LINCOMP_19_20            12
  52
  53 #define AD5780_LINCOMP_0_10             0
  54 #define AD5780_LINCOMP_10_20            12
  55
  56 /* Software Control Register */
  57 #define AD5791_SWCTRL_LDAC              (1 << 0)
  58 #define AD5791_SWCTRL_CLR               (1 << 1)
  59 #define AD5791_SWCTRL_RESET             (1 << 2)
  60
  61 #define AD5791_DAC_PWRDN_6K             0
  62 #define AD5791_DAC_PWRDN_3STATE         1
  63
  64 /**
  65  * struct ad5791_chip_info - chip specific information
  66  * @get_lin_comp:       function pointer to the device specific function
  67  */
  68
  69 struct ad5791_chip_info {
  70         int (*get_lin_comp)     (unsigned int span);
  71 };
  72
  73 /**
  74  * struct ad5791_state - driver instance specific data
  75  * @us:                 spi_device
  76  * @reg_vdd:            positive supply regulator
  77  * @reg_vss:            negative supply regulator
  78  * @chip_info:          chip model specific constants
  79  * @vref_mv:            actual reference voltage used
  80  * @vref_neg_mv:        voltage of the negative supply
  81  * @pwr_down_mode       current power down mode
  82  */
  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 /**
 102  * ad5791_supported_device_ids:
 103  */
 104
 105 enum ad5791_supported_device_ids {
 106         ID_AD5760,
 107         ID_AD5780,
 108         ID_AD5781,
 109         ID_AD5791,
 110 };
 111
 112 static int ad5791_spi_write(struct ad5791_state *st, u8 addr, u32 val)
 113 {
 114         st->data[0].d32 = cpu_to_be32(AD5791_CMD_WRITE |
 115                               AD5791_ADDR(addr) |
 116                               (val & AD5791_DAC_MASK));
 117
 118         return spi_write(st->spi, &st->data[0].d8[1], 3);
 119 }
 120
 121 static int ad5791_spi_read(struct ad5791_state *st, u8 addr, u32 *val)
 122 {
 123         int ret;
 124         struct spi_transfer xfers[] = {
 125                 {
 126                         .tx_buf = &st->data[0].d8[1],
 127                         .bits_per_word = 8,
 128                         .len = 3,
 129                         .cs_change = 1,
 130                 }, {
 131                         .tx_buf = &st->data[1].d8[1],
 132                         .rx_buf = &st->data[2].d8[1],
 133                         .bits_per_word = 8,
 134                         .len = 3,
 135                 },
 136         };
 137
 138         st->data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
 139                               AD5791_ADDR(addr));
 140         st->data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
 141
 142         ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
 143
 144         *val = be32_to_cpu(st->data[2].d32);
 145
 146         return ret;
 147 }
 148
 149 static const char * const ad5791_powerdown_modes[] = {
 150         "6kohm_to_gnd",
 151         "three_state",
 152 };
 153
 154 static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
 155         const struct iio_chan_spec *chan)
 156 {
 157         struct ad5791_state *st = iio_priv(indio_dev);
 158
 159         return st->pwr_down_mode;
 160 }
 161
 162 static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
 163         const struct iio_chan_spec *chan, unsigned int mode)
 164 {
 165         struct ad5791_state *st = iio_priv(indio_dev);
 166
 167         st->pwr_down_mode = mode;
 168
 169         return 0;
 170 }
 171
 172 static const struct iio_enum ad5791_powerdown_mode_enum = {
 173         .items = ad5791_powerdown_modes,
 174         .num_items = ARRAY_SIZE(ad5791_powerdown_modes),
 175         .get = ad5791_get_powerdown_mode,
 176         .set = ad5791_set_powerdown_mode,
 177 };
 178
 179 static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
 180         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 181 {
 182         struct ad5791_state *st = iio_priv(indio_dev);
 183
 184         return sprintf(buf, "%d\n", st->pwr_down);
 185 }
 186
 187 static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
 188          uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 189          size_t len)
 190 {
 191         bool pwr_down;
 192         int ret;
 193         struct ad5791_state *st = iio_priv(indio_dev);
 194
 195         ret = strtobool(buf, &pwr_down);
 196         if (ret)
 197                 return ret;
 198
 199         if (!pwr_down) {
 200                 st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 201         } else {
 202                 if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
 203                         st->ctrl |= AD5791_CTRL_OPGND;
 204                 else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
 205                         st->ctrl |= AD5791_CTRL_DACTRI;
 206         }
 207         st->pwr_down = pwr_down;
 208
 209         ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl);
 210
 211         return ret ? ret : len;
 212 }
 213
 214 static int ad5791_get_lin_comp(unsigned int span)
 215 {
 216         if (span <= 10000)
 217                 return AD5791_LINCOMP_0_10;
 218         else if (span <= 12000)
 219                 return AD5791_LINCOMP_10_12;
 220         else if (span <= 16000)
 221                 return AD5791_LINCOMP_12_16;
 222         else if (span <= 19000)
 223                 return AD5791_LINCOMP_16_19;
 224         else
 225                 return AD5791_LINCOMP_19_20;
 226 }
 227
 228 static int ad5780_get_lin_comp(unsigned int span)
 229 {
 230         if (span <= 10000)
 231                 return AD5780_LINCOMP_0_10;
 232         else
 233                 return AD5780_LINCOMP_10_20;
 234 }
 235 static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
 236         [ID_AD5760] = {
 237                 .get_lin_comp = ad5780_get_lin_comp,
 238         },
 239         [ID_AD5780] = {
 240                 .get_lin_comp = ad5780_get_lin_comp,
 241         },
 242         [ID_AD5781] = {
 243                 .get_lin_comp = ad5791_get_lin_comp,
 244         },
 245         [ID_AD5791] = {
 246                 .get_lin_comp = ad5791_get_lin_comp,
 247         },
 248 };
 249
 250 static int ad5791_read_raw(struct iio_dev *indio_dev,
 251                            struct iio_chan_spec const *chan,
 252                            int *val,
 253                            int *val2,
 254                            long m)
 255 {
 256         struct ad5791_state *st = iio_priv(indio_dev);
 257         u64 val64;
 258         int ret;
 259
 260         switch (m) {
 261         case IIO_CHAN_INFO_RAW:
 262                 ret = ad5791_spi_read(st, chan->address, val);
 263                 if (ret)
 264                         return ret;
 265                 *val &= AD5791_DAC_MASK;
 266                 *val >>= chan->scan_type.shift;
 267                 return IIO_VAL_INT;
 268         case IIO_CHAN_INFO_SCALE:
 269                 *val = st->vref_mv;
 270                 *val2 = (1 << chan->scan_type.realbits) - 1;
 271                 return IIO_VAL_FRACTIONAL;
 272         case IIO_CHAN_INFO_OFFSET:
 273                 val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
 274                 do_div(val64, st->vref_mv);
 275                 *val = -val64;
 276                 return IIO_VAL_INT;
 277         default:
 278                 return -EINVAL;
 279         }
 280
 281 };
 282
 283 static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
 284         {
 285                 .name = "powerdown",
 286                 .shared = IIO_SHARED_BY_TYPE,
 287                 .read = ad5791_read_dac_powerdown,
 288                 .write = ad5791_write_dac_powerdown,
 289         },
 290         IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
 291                  &ad5791_powerdown_mode_enum),
 292         IIO_ENUM_AVAILABLE("powerdown_mode", &ad5791_powerdown_mode_enum),
 293         { },
 294 };
 295
 296 #define AD5791_CHAN(bits, _shift) {                     \
 297         .type = IIO_VOLTAGE,                            \
 298         .output = 1,                                    \
 299         .indexed = 1,                                   \
 300         .address = AD5791_ADDR_DAC0,                    \
 301         .channel = 0,                                   \
 302         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 303         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
 304                 BIT(IIO_CHAN_INFO_OFFSET),              \
 305         .scan_type = {                                  \
 306                 .sign = 'u',                            \
 307                 .realbits = (bits),                     \
 308                 .storagebits = 24,                      \
 309                 .shift = (_shift),                      \
 310         },                                              \
 311         .ext_info = ad5791_ext_info,                    \
 312 }
 313
 314 static const struct iio_chan_spec ad5791_channels[] = {
 315         [ID_AD5760] = AD5791_CHAN(16, 4),
 316         [ID_AD5780] = AD5791_CHAN(18, 2),
 317         [ID_AD5781] = AD5791_CHAN(18, 2),
 318         [ID_AD5791] = AD5791_CHAN(20, 0)
 319 };
 320
 321 static int ad5791_write_raw(struct iio_dev *indio_dev,
 322                             struct iio_chan_spec const *chan,
 323                             int val,
 324                             int val2,
 325                             long mask)
 326 {
 327         struct ad5791_state *st = iio_priv(indio_dev);
 328
 329         switch (mask) {
 330         case IIO_CHAN_INFO_RAW:
 331                 val &= AD5791_RES_MASK(chan->scan_type.realbits);
 332                 val <<= chan->scan_type.shift;
 333
 334                 return ad5791_spi_write(st, chan->address, val);
 335
 336         default:
 337                 return -EINVAL;
 338         }
 339 }
 340
 341 static const struct iio_info ad5791_info = {
 342         .read_raw = &ad5791_read_raw,
 343         .write_raw = &ad5791_write_raw,
 344         .driver_module = THIS_MODULE,
 345 };
 346
 347 static int ad5791_probe(struct spi_device *spi)
 348 {
 349         struct ad5791_platform_data *pdata = spi->dev.platform_data;
 350         struct iio_dev *indio_dev;
 351         struct ad5791_state *st;
 352         int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
 353
 354         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 355         if (!indio_dev)
 356                 return -ENOMEM;
 357         st = iio_priv(indio_dev);
 358         st->reg_vdd = devm_regulator_get(&spi->dev, "vdd");
 359         if (!IS_ERR(st->reg_vdd)) {
 360                 ret = regulator_enable(st->reg_vdd);
 361                 if (ret)
 362                         return ret;
 363
 364                 ret = regulator_get_voltage(st->reg_vdd);
 365                 if (ret < 0)
 366                         goto error_disable_reg_pos;
 367
 368                 pos_voltage_uv = ret;
 369         }
 370
 371         st->reg_vss = devm_regulator_get(&spi->dev, "vss");
 372         if (!IS_ERR(st->reg_vss)) {
 373                 ret = regulator_enable(st->reg_vss);
 374                 if (ret)
 375                         goto error_disable_reg_pos;
 376
 377                 ret = regulator_get_voltage(st->reg_vss);
 378                 if (ret < 0)
 379                         goto error_disable_reg_neg;
 380
 381                 neg_voltage_uv = ret;
 382         }
 383
 384         st->pwr_down = true;
 385         st->spi = spi;
 386
 387         if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd)) {
 388                 st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
 389                 st->vref_neg_mv = neg_voltage_uv / 1000;
 390         } else if (pdata) {
 391                 st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
 392                 st->vref_neg_mv = pdata->vref_neg_mv;
 393         } else {
 394                 dev_warn(&spi->dev, "reference voltage unspecified\n");
 395         }
 396
 397         ret = ad5791_spi_write(st, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
 398         if (ret)
 399                 goto error_disable_reg_neg;
 400
 401         st->chip_info = &ad5791_chip_info_tbl[spi_get_device_id(spi)
 402                                               ->driver_data];
 403
 404
 405         st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
 406                   | ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
 407                   AD5791_CTRL_BIN2SC;
 408
 409         ret = ad5791_spi_write(st, AD5791_ADDR_CTRL, st->ctrl |
 410                 AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 411         if (ret)
 412                 goto error_disable_reg_neg;
 413
 414         spi_set_drvdata(spi, indio_dev);
 415         indio_dev->dev.parent = &spi->dev;
 416         indio_dev->info = &ad5791_info;
 417         indio_dev->modes = INDIO_DIRECT_MODE;
 418         indio_dev->channels
 419                 = &ad5791_channels[spi_get_device_id(spi)->driver_data];
 420         indio_dev->num_channels = 1;
 421         indio_dev->name = spi_get_device_id(st->spi)->name;
 422         ret = iio_device_register(indio_dev);
 423         if (ret)
 424                 goto error_disable_reg_neg;
 425
 426         return 0;
 427
 428 error_disable_reg_neg:
 429         if (!IS_ERR(st->reg_vss))
 430                 regulator_disable(st->reg_vss);
 431 error_disable_reg_pos:
 432         if (!IS_ERR(st->reg_vdd))
 433                 regulator_disable(st->reg_vdd);
 434         return ret;
 435 }
 436
 437 static int ad5791_remove(struct spi_device *spi)
 438 {
 439         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 440         struct ad5791_state *st = iio_priv(indio_dev);
 441
 442         iio_device_unregister(indio_dev);
 443         if (!IS_ERR(st->reg_vdd))
 444                 regulator_disable(st->reg_vdd);
 445
 446         if (!IS_ERR(st->reg_vss))
 447                 regulator_disable(st->reg_vss);
 448
 449         return 0;
 450 }
 451
 452 static const struct spi_device_id ad5791_id[] = {
 453         {"ad5760", ID_AD5760},
 454         {"ad5780", ID_AD5780},
 455         {"ad5781", ID_AD5781},
 456         {"ad5790", ID_AD5791},
 457         {"ad5791", ID_AD5791},
 458         {}
 459 };
 460 MODULE_DEVICE_TABLE(spi, ad5791_id);
 461
 462 static struct spi_driver ad5791_driver = {
 463         .driver = {
 464                    .name = "ad5791",
 465                    .owner = THIS_MODULE,
 466                    },
 467         .probe = ad5791_probe,
 468         .remove = ad5791_remove,
 469         .id_table = ad5791_id,
 470 };
 471 module_spi_driver(ad5791_driver);
 472
 473 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 474 MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
 475 MODULE_LICENSE("GPL v2");