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