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_message msg;
 129         struct spi_transfer xfers[] = {
 130                 {
 131                         .tx_buf = &data[0].d8[1],
 132                         .bits_per_word = 8,
 133                         .len = 3,
 134                         .cs_change = 1,
 135                 }, {
 136                         .tx_buf = &data[1].d8[1],
 137                         .rx_buf = &data[2].d8[1],
 138                         .bits_per_word = 8,
 139                         .len = 3,
 140                 },
 141         };
 142
 143         data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
 144                               AD5791_ADDR(addr));
 145         data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
 146
 147         spi_message_init(&msg);
 148         spi_message_add_tail(&xfers[0], &msg);
 149         spi_message_add_tail(&xfers[1], &msg);
 150         ret = spi_sync(spi, &msg);
 151
 152         *val = be32_to_cpu(data[2].d32);
 153
 154         return ret;
 155 }
 156
 157 static const char * const ad5791_powerdown_modes[] = {
 158         "6kohm_to_gnd",
 159         "three_state",
 160 };
 161
 162 static int ad5791_get_powerdown_mode(struct iio_dev *indio_dev,
 163         const struct iio_chan_spec *chan)
 164 {
 165         struct ad5791_state *st = iio_priv(indio_dev);
 166
 167         return st->pwr_down_mode;
 168 }
 169
 170 static int ad5791_set_powerdown_mode(struct iio_dev *indio_dev,
 171         const struct iio_chan_spec *chan, unsigned int mode)
 172 {
 173         struct ad5791_state *st = iio_priv(indio_dev);
 174
 175         st->pwr_down_mode = mode;
 176
 177         return 0;
 178 }
 179
 180 static const struct iio_enum ad5791_powerdown_mode_enum = {
 181         .items = ad5791_powerdown_modes,
 182         .num_items = ARRAY_SIZE(ad5791_powerdown_modes),
 183         .get = ad5791_get_powerdown_mode,
 184         .set = ad5791_set_powerdown_mode,
 185 };
 186
 187 static ssize_t ad5791_read_dac_powerdown(struct iio_dev *indio_dev,
 188         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 189 {
 190         struct ad5791_state *st = iio_priv(indio_dev);
 191
 192         return sprintf(buf, "%d\n", st->pwr_down);
 193 }
 194
 195 static ssize_t ad5791_write_dac_powerdown(struct iio_dev *indio_dev,
 196          uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 197          size_t len)
 198 {
 199         bool pwr_down;
 200         int ret;
 201         struct ad5791_state *st = iio_priv(indio_dev);
 202
 203         ret = strtobool(buf, &pwr_down);
 204         if (ret)
 205                 return ret;
 206
 207         if (!pwr_down) {
 208                 st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 209         } else {
 210                 if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
 211                         st->ctrl |= AD5791_CTRL_OPGND;
 212                 else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
 213                         st->ctrl |= AD5791_CTRL_DACTRI;
 214         }
 215         st->pwr_down = pwr_down;
 216
 217         ret = ad5791_spi_write(st->spi, AD5791_ADDR_CTRL, st->ctrl);
 218
 219         return ret ? ret : len;
 220 }
 221
 222 static int ad5791_get_lin_comp(unsigned int span)
 223 {
 224         if (span <= 10000)
 225                 return AD5791_LINCOMP_0_10;
 226         else if (span <= 12000)
 227                 return AD5791_LINCOMP_10_12;
 228         else if (span <= 16000)
 229                 return AD5791_LINCOMP_12_16;
 230         else if (span <= 19000)
 231                 return AD5791_LINCOMP_16_19;
 232         else
 233                 return AD5791_LINCOMP_19_20;
 234 }
 235
 236 static int ad5780_get_lin_comp(unsigned int span)
 237 {
 238         if (span <= 10000)
 239                 return AD5780_LINCOMP_0_10;
 240         else
 241                 return AD5780_LINCOMP_10_20;
 242 }
 243 static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
 244         [ID_AD5760] = {
 245                 .get_lin_comp = ad5780_get_lin_comp,
 246         },
 247         [ID_AD5780] = {
 248                 .get_lin_comp = ad5780_get_lin_comp,
 249         },
 250         [ID_AD5781] = {
 251                 .get_lin_comp = ad5791_get_lin_comp,
 252         },
 253         [ID_AD5791] = {
 254                 .get_lin_comp = ad5791_get_lin_comp,
 255         },
 256 };
 257
 258 static int ad5791_read_raw(struct iio_dev *indio_dev,
 259                            struct iio_chan_spec const *chan,
 260                            int *val,
 261                            int *val2,
 262                            long m)
 263 {
 264         struct ad5791_state *st = iio_priv(indio_dev);
 265         u64 val64;
 266         int ret;
 267
 268         switch (m) {
 269         case IIO_CHAN_INFO_RAW:
 270                 ret = ad5791_spi_read(st->spi, chan->address, val);
 271                 if (ret)
 272                         return ret;
 273                 *val &= AD5791_DAC_MASK;
 274                 *val >>= chan->scan_type.shift;
 275                 return IIO_VAL_INT;
 276         case IIO_CHAN_INFO_SCALE:
 277                 *val = 0;
 278                 *val2 = (((u64)st->vref_mv) * 1000000ULL) >> chan->scan_type.realbits;
 279                 return IIO_VAL_INT_PLUS_MICRO;
 280         case IIO_CHAN_INFO_OFFSET:
 281                 val64 = (((u64)st->vref_neg_mv) << chan->scan_type.realbits);
 282                 do_div(val64, st->vref_mv);
 283                 *val = -val64;
 284                 return IIO_VAL_INT;
 285         default:
 286                 return -EINVAL;
 287         }
 288
 289 };
 290
 291 static const struct iio_chan_spec_ext_info ad5791_ext_info[] = {
 292         {
 293                 .name = "powerdown",
 294                 .shared = true,
 295                 .read = ad5791_read_dac_powerdown,
 296                 .write = ad5791_write_dac_powerdown,
 297         },
 298         IIO_ENUM("powerdown_mode", true, &ad5791_powerdown_mode_enum),
 299         IIO_ENUM_AVAILABLE("powerdown_mode", &ad5791_powerdown_mode_enum),
 300         { },
 301 };
 302
 303 #define AD5791_CHAN(bits, shift) {                      \
 304         .type = IIO_VOLTAGE,                            \
 305         .output = 1,                                    \
 306         .indexed = 1,                                   \
 307         .address = AD5791_ADDR_DAC0,                    \
 308         .channel = 0,                                   \
 309         .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |   \
 310                 IIO_CHAN_INFO_SCALE_SHARED_BIT |        \
 311                 IIO_CHAN_INFO_OFFSET_SHARED_BIT,        \
 312         .scan_type = IIO_ST('u', bits, 24, shift),      \
 313         .ext_info = ad5791_ext_info,                    \
 314 }
 315
 316 static const struct iio_chan_spec ad5791_channels[] = {
 317         [ID_AD5760] = AD5791_CHAN(16, 4),
 318         [ID_AD5780] = AD5791_CHAN(18, 2),
 319         [ID_AD5781] = AD5791_CHAN(18, 2),
 320         [ID_AD5791] = AD5791_CHAN(20, 0)
 321 };
 322
 323 static int ad5791_write_raw(struct iio_dev *indio_dev,
 324                             struct iio_chan_spec const *chan,
 325                             int val,
 326                             int val2,
 327                             long mask)
 328 {
 329         struct ad5791_state *st = iio_priv(indio_dev);
 330
 331         switch (mask) {
 332         case IIO_CHAN_INFO_RAW:
 333                 val &= AD5791_RES_MASK(chan->scan_type.realbits);
 334                 val <<= chan->scan_type.shift;
 335
 336                 return ad5791_spi_write(st->spi, chan->address, val);
 337
 338         default:
 339                 return -EINVAL;
 340         }
 341 }
 342
 343 static const struct iio_info ad5791_info = {
 344         .read_raw = &ad5791_read_raw,
 345         .write_raw = &ad5791_write_raw,
 346         .driver_module = THIS_MODULE,
 347 };
 348
 349 static int ad5791_probe(struct spi_device *spi)
 350 {
 351         struct ad5791_platform_data *pdata = spi->dev.platform_data;
 352         struct iio_dev *indio_dev;
 353         struct ad5791_state *st;
 354         int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
 355
 356         indio_dev = iio_device_alloc(sizeof(*st));
 357         if (indio_dev == NULL) {
 358                 ret = -ENOMEM;
 359                 goto error_ret;
 360         }
 361         st = iio_priv(indio_dev);
 362         st->reg_vdd = regulator_get(&spi->dev, "vdd");
 363         if (!IS_ERR(st->reg_vdd)) {
 364                 ret = regulator_enable(st->reg_vdd);
 365                 if (ret)
 366                         goto error_put_reg_pos;
 367
 368                 ret = regulator_get_voltage(st->reg_vdd);
 369                 if (ret < 0)
 370                         goto error_disable_reg_pos;
 371
 372                 pos_voltage_uv = ret;
 373         }
 374
 375         st->reg_vss = regulator_get(&spi->dev, "vss");
 376         if (!IS_ERR(st->reg_vss)) {
 377                 ret = regulator_enable(st->reg_vss);
 378                 if (ret)
 379                         goto error_put_reg_neg;
 380
 381                 ret = regulator_get_voltage(st->reg_vss);
 382                 if (ret < 0)
 383                         goto error_disable_reg_neg;
 384
 385                 neg_voltage_uv = ret;
 386         }
 387
 388         st->pwr_down = true;
 389         st->spi = spi;
 390
 391         if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd)) {
 392                 st->vref_mv = (pos_voltage_uv + neg_voltage_uv) / 1000;
 393                 st->vref_neg_mv = neg_voltage_uv / 1000;
 394         } else if (pdata) {
 395                 st->vref_mv = pdata->vref_pos_mv + pdata->vref_neg_mv;
 396                 st->vref_neg_mv = pdata->vref_neg_mv;
 397         } else {
 398                 dev_warn(&spi->dev, "reference voltage unspecified\n");
 399         }
 400
 401         ret = ad5791_spi_write(spi, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
 402         if (ret)
 403                 goto error_disable_reg_neg;
 404
 405         st->chip_info = &ad5791_chip_info_tbl[spi_get_device_id(spi)
 406                                               ->driver_data];
 407
 408
 409         st->ctrl = AD5761_CTRL_LINCOMP(st->chip_info->get_lin_comp(st->vref_mv))
 410                   | ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
 411                   AD5791_CTRL_BIN2SC;
 412
 413         ret = ad5791_spi_write(spi, AD5791_ADDR_CTRL, st->ctrl |
 414                 AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
 415         if (ret)
 416                 goto error_disable_reg_neg;
 417
 418         spi_set_drvdata(spi, indio_dev);
 419         indio_dev->dev.parent = &spi->dev;
 420         indio_dev->info = &ad5791_info;
 421         indio_dev->modes = INDIO_DIRECT_MODE;
 422         indio_dev->channels
 423                 = &ad5791_channels[spi_get_device_id(spi)->driver_data];
 424         indio_dev->num_channels = 1;
 425         indio_dev->name = spi_get_device_id(st->spi)->name;
 426         ret = iio_device_register(indio_dev);
 427         if (ret)
 428                 goto error_disable_reg_neg;
 429
 430         return 0;
 431
 432 error_disable_reg_neg:
 433         if (!IS_ERR(st->reg_vss))
 434                 regulator_disable(st->reg_vss);
 435 error_put_reg_neg:
 436         if (!IS_ERR(st->reg_vss))
 437                 regulator_put(st->reg_vss);
 438
 439 error_disable_reg_pos:
 440         if (!IS_ERR(st->reg_vdd))
 441                 regulator_disable(st->reg_vdd);
 442 error_put_reg_pos:
 443         if (!IS_ERR(st->reg_vdd))
 444                 regulator_put(st->reg_vdd);
 445         iio_device_free(indio_dev);
 446 error_ret:
 447
 448         return ret;
 449 }
 450
 451 static int ad5791_remove(struct spi_device *spi)
 452 {
 453         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 454         struct ad5791_state *st = iio_priv(indio_dev);
 455
 456         iio_device_unregister(indio_dev);
 457         if (!IS_ERR(st->reg_vdd)) {
 458                 regulator_disable(st->reg_vdd);
 459                 regulator_put(st->reg_vdd);
 460         }
 461
 462         if (!IS_ERR(st->reg_vss)) {
 463                 regulator_disable(st->reg_vss);
 464                 regulator_put(st->reg_vss);
 465         }
 466         iio_device_free(indio_dev);
 467
 468         return 0;
 469 }
 470
 471 static const struct spi_device_id ad5791_id[] = {
 472         {"ad5760", ID_AD5760},
 473         {"ad5780", ID_AD5780},
 474         {"ad5781", ID_AD5781},
 475         {"ad5790", ID_AD5791},
 476         {"ad5791", ID_AD5791},
 477         {}
 478 };
 479 MODULE_DEVICE_TABLE(spi, ad5791_id);
 480
 481 static struct spi_driver ad5791_driver = {
 482         .driver = {
 483                    .name = "ad5791",
 484                    .owner = THIS_MODULE,
 485                    },
 486         .probe = ad5791_probe,
 487         .remove = ad5791_remove,
 488         .id_table = ad5791_id,
 489 };
 490 module_spi_driver(ad5791_driver);
 491
 492 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 493 MODULE_DESCRIPTION("Analog Devices AD5760/AD5780/AD5781/AD5790/AD5791 DAC");
 494 MODULE_LICENSE("GPL v2");