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
  96 /**
  97  * ad5791_supported_device_ids:
  98  */
  99
 100 enum ad5791_supported_device_ids {
 101         ID_AD5760,
 102         ID_AD5780,
 103         ID_AD5781,
 104         ID_AD5791,
 105 };
 106
 107 static int ad5791_spi_write(struct spi_device *spi, u8 addr, u32 val)
 108 {
 109         union {
 110                 u32 d32;
 111                 u8 d8[4];
 112         } data;
 113
 114         data.d32 = cpu_to_be32(AD5791_CMD_WRITE |
 115                               AD5791_ADDR(addr) |
 116                               (val & AD5791_DAC_MASK));
 117
 118         return spi_write(spi, &data.d8[1], 3);
 119 }
 120
 121 static int ad5791_spi_read(struct spi_device *spi, u8 addr, u32 *val)
 122 {
 123         union {
 124                 u32 d32;
 125                 u8 d8[4];
 126         } data[3];
 127         int ret;
 128         struct spi_transfer xfers[] = {
 129                 {
 130                         .tx_buf = &data[0].d8[1],
 131                         .bits_per_word = 8,
 132                         .len = 3,
 133                         .cs_change = 1,
 134                 }, {
 135                         .tx_buf = &data[1].d8[1],
 136                         .rx_buf = &data[2].d8[1],
 137                         .bits_per_word = 8,
 138                         .len = 3,
 139                 },
 140         };
 141
 142         data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
 143                               AD5791_ADDR(addr));
 144         data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
 145
 146         ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));
 147
 148         *val = be32_to_cpu(data[2].d32);
 149
 150         return ret;
 151 }
 152
 153 static const char * const ad5791_powerdown_modes[] = {
 154         "6kohm_to_gnd",
 155         "three_state",
 156 };
 157
 158 static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
 159         const struct iio_chan_spec *chan)
 160 {
 161         struct ad5791_state *st = iio_priv(indio_dev);
 162
 163         return st->pwr_down_mode;
 164 }
 165
 166 static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
 167         const struct iio_chan_spec *chan, unsigned int mode)
 168 {
 169         struct ad5791_state *st = iio_priv(indio_dev);
 170
 171         st->pwr_down_mode = mode;
 172
 173         return 0;
 174 }
 175
 176 static const struct iio_enum ad5791_powerdown_mode_enum = {
 177         .items = ad5791_powerdown_modes,
 178         .num_items = ARRAY_SIZE(ad5791_powerdown_modes),
 179         .get = ad5791_get_powerdown_mode,
 180         .set = ad5791_set_powerdown_mode,
 181 };
 182
 183 static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
 184         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 185 {
 186         struct ad5791_state *st = iio_priv(indio_dev);
 187
 188         return sprintf(buf, "%d\n", st->pwr_down);
 189 }
 190
 191 static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
 192          uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 193          size_t len)
 194 {
 195         bool pwr_down;
 196         int ret;
 197         struct ad5791_state *st = iio_priv(indio_dev);
 198
 199         ret = strtobool(buf, &pwr_down);
 200         if (ret)
 201                 return ret;
 202
 203         if (!pwr_down) {
 204                 st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 205         } else {
 206                 if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
 207                         st->ctrl |= AD5791_CTRL_OPGND;
 208                 else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
 209                         st->ctrl |= AD5791_CTRL_DACTRI;
 210         }
 211         st->pwr_down = pwr_down;
 212
 213         ret = ad5791_spi_write(st->spi, AD5791_ADDR_CTRL, st->ctrl);
 214
 215         return ret ? ret : len;
 216 }
 217
 218 static int ad5791_get_lin_comp(unsigned int span)
 219 {
 220         if (span <= 10000)
 221                 return AD5791_LINCOMP_0_10;
 222         else if (span <= 12000)
 223                 return AD5791_LINCOMP_10_12;
 224         else if (span <= 16000)
 225                 return AD5791_LINCOMP_12_16;
 226         else if (span <= 19000)
 227                 return AD5791_LINCOMP_16_19;
 228         else
 229                 return AD5791_LINCOMP_19_20;
 230 }
 231
 232 static int ad5780_get_lin_comp(unsigned int span)
 233 {
 234         if (span <= 10000)
 235                 return AD5780_LINCOMP_0_10;
 236         else
 237                 return AD5780_LINCOMP_10_20;
 238 }
 239 static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
 240         [ID_AD5760] = {
 241                 .get_lin_comp = ad5780_get_lin_comp,
 242         },
 243         [ID_AD5780] = {
 244                 .get_lin_comp = ad5780_get_lin_comp,
 245         },
 246         [ID_AD5781] = {
 247                 .get_lin_comp = ad5791_get_lin_comp,
 248         },
 249         [ID_AD5791] = {
 250                 .get_lin_comp = ad5791_get_lin_comp,
 251         },
 252 };
 253
 254 static int ad5791_read_raw(struct iio_dev *indio_dev,
 255                            struct iio_chan_spec const *chan,
 256                            int *val,
 257                            int *val2,
 258                            long m)
 259 {
 260         struct ad5791_state *st = iio_priv(indio_dev);
 261         u64 val64;
 262         int ret;
 263
 264         switch (m) {
 265         case IIO_CHAN_INFO_RAW:
 266                 ret = ad5791_spi_read(st->spi, chan->address, val);
 267                 if (ret)
 268                         return ret;
 269                 *val &= AD5791_DAC_MASK;
 270                 *val >>= chan->scan_type.shift;
 271                 return IIO_VAL_INT;
 272         case IIO_CHAN_INFO_SCALE:
 273                 *val = st->vref_mv;
 274                 *val2 = (1 << chan->scan_type.realbits) - 1;
 275                 return IIO_VAL_FRACTIONAL;
 276         case IIO_CHAN_INFO_OFFSET:
 277                 val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
 278                 do_div(val64, st->vref_mv);
 279                 *val = -val64;
 280                 return IIO_VAL_INT;
 281         default:
 282                 return -EINVAL;
 283         }
 284
 285 };
 286
 287 static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
 288         {
 289                 .name = "powerdown",
 290                 .shared = IIO_SHARED_BY_TYPE,
 291                 .read = ad5791_read_dac_powerdown,
 292                 .write = ad5791_write_dac_powerdown,
 293         },
 294         IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
 295                  &ad5791_powerdown_mode_enum),
 296         IIO_ENUM_AVAILABLE("powerdown_mode", &ad5791_powerdown_mode_enum),
 297         { },
 298 };
 299
 300 #define AD5791_CHAN(bits, shift) {                      \
 301         .type = IIO_VOLTAGE,                            \
 302         .output = 1,                                    \
 303         .indexed = 1,                                   \
 304         .address = AD5791_ADDR_DAC0,                    \
 305         .channel = 0,                                   \
 306         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 307         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
 308                 BIT(IIO_CHAN_INFO_OFFSET),              \
 309         .scan_type = IIO_ST('u', bits, 24, shift),      \
 310         .ext_info = ad5791_ext_info,                    \
 311 }
 312
 313 static const struct iio_chan_spec ad5791_channels[] = {
 314         [ID_AD5760] = AD5791_CHAN(16, 4),
 315         [ID_AD5780] = AD5791_CHAN(18, 2),
 316         [ID_AD5781] = AD5791_CHAN(18, 2),
 317         [ID_AD5791] = AD5791_CHAN(20, 0)
 318 };
 319
 320 static int ad5791_write_raw(struct iio_dev *indio_dev,
 321                             struct iio_chan_spec const *chan,
 322                             int val,
 323                             int val2,
 324                             long mask)
 325 {
 326         struct ad5791_state *st = iio_priv(indio_dev);
 327
 328         switch (mask) {
 329         case IIO_CHAN_INFO_RAW:
 330                 val &= AD5791_RES_MASK(chan->scan_type.realbits);
 331                 val <<= chan->scan_type.shift;
 332
 333                 return ad5791_spi_write(st->spi, chan->address, val);
 334
 335         default:
 336                 return -EINVAL;
 337         }
 338 }
 339
 340 static const struct iio_info ad5791_info = {
 341         .read_raw = &ad5791_read_raw,
 342         .write_raw = &ad5791_write_raw,
 343         .driver_module = THIS_MODULE,
 344 };
 345
 346 static int ad5791_probe(struct spi_device *spi)
 347 {
 348         struct ad5791_platform_data *pdata = spi->dev.platform_data;
 349         struct iio_dev *indio_dev;
 350         struct ad5791_state *st;
 351         int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
 352
 353         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 354         if (!indio_dev)
 355                 return -ENOMEM;
 356         st = iio_priv(indio_dev);
 357         st->reg_vdd = devm_regulator_get(&spi->dev, "vdd");
 358         if (!IS_ERR(st->reg_vdd)) {
 359                 ret = regulator_enable(st->reg_vdd);
 360                 if (ret)
 361                         return ret;
 362
 363                 ret = regulator_get_voltage(st->reg_vdd);
 364                 if (ret < 0)
 365                         goto error_disable_reg_pos;
 366
 367                 pos_voltage_uv = ret;
 368         }
 369
 370         st->reg_vss = devm_regulator_get(&spi->dev, "vss");
 371         if (!IS_ERR(st->reg_vss)) {
 372                 ret = regulator_enable(st->reg_vss);
 373                 if (ret)
 374                         goto error_disable_reg_pos;
 375
 376                 ret = regulator_get_voltage(st->reg_vss);
 377                 if (ret < 0)
 378                         goto error_disable_reg_neg;
 379
 380                 neg_voltage_uv = ret;
 381         }
 382
 383         st->pwr_down = true;
 384         st->spi = spi;
 385
 386         if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd)) {
 387                 st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
 388                 st->vref_neg_mv = neg_voltage_uv / 1000;
 389         } else if (pdata) {
 390                 st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
 391                 st->vref_neg_mv = pdata->vref_neg_mv;
 392         } else {
 393                 dev_warn(&spi->dev, "reference voltage unspecified\n");
 394         }
 395
 396         ret = ad5791_spi_write(spi, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
 397         if (ret)
 398                 goto error_disable_reg_neg;
 399
 400         st->chip_info = &ad5791_chip_info_tbl[spi_get_device_id(spi)
 401                                               ->driver_data];
 402
 403
 404         st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
 405                   | ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
 406                   AD5791_CTRL_BIN2SC;
 407
 408         ret = ad5791_spi_write(spi, AD5791_ADDR_CTRL, st->ctrl |
 409                 AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 410         if (ret)
 411                 goto error_disable_reg_neg;
 412
 413         spi_set_drvdata(spi, indio_dev);
 414         indio_dev->dev.parent = &spi->dev;
 415         indio_dev->info = &ad5791_info;
 416         indio_dev->modes = INDIO_DIRECT_MODE;
 417         indio_dev->channels
 418                 = &ad5791_channels[spi_get_device_id(spi)->driver_data];
 419         indio_dev->num_channels = 1;
 420         indio_dev->name = spi_get_device_id(st->spi)->name;
 421         ret = iio_device_register(indio_dev);
 422         if (ret)
 423                 goto error_disable_reg_neg;
 424
 425         return 0;
 426
 427 error_disable_reg_neg:
 428         if (!IS_ERR(st->reg_vss))
 429                 regulator_disable(st->reg_vss);
 430 error_disable_reg_pos:
 431         if (!IS_ERR(st->reg_vdd))
 432                 regulator_disable(st->reg_vdd);
 433         return ret;
 434 }
 435
 436 static int ad5791_remove(struct spi_device *spi)
 437 {
 438         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 439         struct ad5791_state *st = iio_priv(indio_dev);
 440
 441         iio_device_unregister(indio_dev);
 442         if (!IS_ERR(st->reg_vdd))
 443                 regulator_disable(st->reg_vdd);
 444
 445         if (!IS_ERR(st->reg_vss))
 446                 regulator_disable(st->reg_vss);
 447
 448         return 0;
 449 }
 450
 451 static const struct spi_device_id ad5791_id[] = {
 452         {"ad5760", ID_AD5760},
 453         {"ad5780", ID_AD5780},
 454         {"ad5781", ID_AD5781},
 455         {"ad5790", ID_AD5791},
 456         {"ad5791", ID_AD5791},
 457         {}
 458 };
 459 MODULE_DEVICE_TABLE(spi, ad5791_id);
 460
 461 static struct spi_driver ad5791_driver = {
 462         .driver = {
 463                    .name = "ad5791",
 464                    .owner = THIS_MODULE,
 465                    },
 466         .probe = ad5791_probe,
 467         .remove = ad5791_remove,
 468         .id_table = ad5791_id,
 469 };
 470 module_spi_driver(ad5791_driver);
 471
 472 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 473 MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
 474 MODULE_LICENSE("GPL v2");