drivers/iio/dac/ltc2632.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * LTC2632 Digital to analog convertors spi driver
   4  *
   5  * Copyright 2017 Maxime Roussin-Bélanger
   6  * expanded by Silvan Murer <silvan.murer@gmail.com>
   7  */
   8
   9 #include <linux/device.h>
  10 #include <linux/spi/spi.h>
  11 #include <linux/module.h>
  12 #include <linux/iio/iio.h>
  13 #include <linux/property.h>
  14 #include <linux/regulator/consumer.h>
  15
  16 #include <asm/unaligned.h>
  17
  18 #define LTC2632_CMD_WRITE_INPUT_N               0x0
  19 #define LTC2632_CMD_UPDATE_DAC_N                0x1
  20 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_ALL    0x2
  21 #define LTC2632_CMD_WRITE_INPUT_N_UPDATE_N      0x3
  22 #define LTC2632_CMD_POWERDOWN_DAC_N             0x4
  23 #define LTC2632_CMD_POWERDOWN_CHIP              0x5
  24 #define LTC2632_CMD_INTERNAL_REFER              0x6
  25 #define LTC2632_CMD_EXTERNAL_REFER              0x7
  26
  27 /**
  28  * struct ltc2632_chip_info - chip specific information
  29  * @channels:           channel spec for the DAC
  30  * @num_channels:       DAC channel count of the chip
  31  * @vref_mv:            internal reference voltage
  32  */
  33 struct ltc2632_chip_info {
  34         const struct iio_chan_spec *channels;
  35         const size_t num_channels;
  36         const int vref_mv;
  37 };
  38
  39 /**
  40  * struct ltc2632_state - driver instance specific data
  41  * @spi_dev:                    pointer to the spi_device struct
  42  * @powerdown_cache_mask:       used to show current channel powerdown state
  43  * @vref_mv:                    used reference voltage (internal or external)
  44  * @vref_reg:           regulator for the reference voltage
  45  */
  46 struct ltc2632_state {
  47         struct spi_device *spi_dev;
  48         unsigned int powerdown_cache_mask;
  49         int vref_mv;
  50         struct regulator *vref_reg;
  51 };
  52
  53 enum ltc2632_supported_device_ids {
  54         ID_LTC2632L12,
  55         ID_LTC2632L10,
  56         ID_LTC2632L8,
  57         ID_LTC2632H12,
  58         ID_LTC2632H10,
  59         ID_LTC2632H8,
  60         ID_LTC2634L12,
  61         ID_LTC2634L10,
  62         ID_LTC2634L8,
  63         ID_LTC2634H12,
  64         ID_LTC2634H10,
  65         ID_LTC2634H8,
  66         ID_LTC2636L12,
  67         ID_LTC2636L10,
  68         ID_LTC2636L8,
  69         ID_LTC2636H12,
  70         ID_LTC2636H10,
  71         ID_LTC2636H8,
  72 };
  73
  74 static int ltc2632_spi_write(struct spi_device *spi,
  75                              u8 cmd, u8 addr, u16 val, u8 shift)
  76 {
  77         u32 data;
  78         u8 msg[3];
  79
  80         /*
  81          * The input shift register is 24 bits wide.
  82          * The next four are the command bits, C3 to C0,
  83          * followed by the 4-bit DAC address, A3 to A0, and then the
  84          * 12-, 10-, 8-bit data-word. The data-word comprises the 12-,
  85          * 10-, 8-bit input code followed by 4, 6, or 8 don't care bits.
  86          */
  87         data = (cmd << 20) | (addr << 16) | (val << shift);
  88         put_unaligned_be24(data, &msg[0]);
  89
  90         return spi_write(spi, msg, sizeof(msg));
  91 }
  92
  93 static int ltc2632_read_raw(struct iio_dev *indio_dev,
  94                             struct iio_chan_spec const *chan,
  95                             int *val,
  96                             int *val2,
  97                             long m)
  98 {
  99         const struct ltc2632_state *st = iio_priv(indio_dev);
 100
 101         switch (m) {
 102         case IIO_CHAN_INFO_SCALE:
 103                 *val = st->vref_mv;
 104                 *val2 = chan->scan_type.realbits;
 105                 return IIO_VAL_FRACTIONAL_LOG2;
 106         }
 107         return -EINVAL;
 108 }
 109
 110 static int ltc2632_write_raw(struct iio_dev *indio_dev,
 111                              struct iio_chan_spec const *chan,
 112                              int val,
 113                              int val2,
 114                              long mask)
 115 {
 116         struct ltc2632_state *st = iio_priv(indio_dev);
 117
 118         switch (mask) {
 119         case IIO_CHAN_INFO_RAW:
 120                 if (val >= (1 << chan->scan_type.realbits) || val < 0)
 121                         return -EINVAL;
 122
 123                 return ltc2632_spi_write(st->spi_dev,
 124                                          LTC2632_CMD_WRITE_INPUT_N_UPDATE_N,
 125                                          chan->address, val,
 126                                          chan->scan_type.shift);
 127         default:
 128                 return -EINVAL;
 129         }
 130 }
 131
 132 static ssize_t ltc2632_read_dac_powerdown(struct iio_dev *indio_dev,
 133                                           uintptr_t private,
 134                                           const struct iio_chan_spec *chan,
 135                                           char *buf)
 136 {
 137         struct ltc2632_state *st = iio_priv(indio_dev);
 138
 139         return sysfs_emit(buf, "%d\n",
 140                           !!(st->powerdown_cache_mask & (1 << chan->channel)));
 141 }
 142
 143 static ssize_t ltc2632_write_dac_powerdown(struct iio_dev *indio_dev,
 144                                            uintptr_t private,
 145                                            const struct iio_chan_spec *chan,
 146                                            const char *buf,
 147                                            size_t len)
 148 {
 149         bool pwr_down;
 150         int ret;
 151         struct ltc2632_state *st = iio_priv(indio_dev);
 152
 153         ret = kstrtobool(buf, &pwr_down);
 154         if (ret)
 155                 return ret;
 156
 157         if (pwr_down)
 158                 st->powerdown_cache_mask |= (1 << chan->channel);
 159         else
 160                 st->powerdown_cache_mask &= ~(1 << chan->channel);
 161
 162         ret = ltc2632_spi_write(st->spi_dev,
 163                                 LTC2632_CMD_POWERDOWN_DAC_N,
 164                                 chan->channel, 0, 0);
 165
 166         return ret ? ret : len;
 167 }
 168
 169 static const struct iio_info ltc2632_info = {
 170         .write_raw      = ltc2632_write_raw,
 171         .read_raw       = ltc2632_read_raw,
 172 };
 173
 174 static const struct iio_chan_spec_ext_info ltc2632_ext_info[] = {
 175         {
 176                 .name = "powerdown",
 177                 .read = ltc2632_read_dac_powerdown,
 178                 .write = ltc2632_write_dac_powerdown,
 179                 .shared = IIO_SEPARATE,
 180         },
 181         { },
 182 };
 183
 184 #define LTC2632_CHANNEL(_chan, _bits) { \
 185                 .type = IIO_VOLTAGE, \
 186                 .indexed = 1, \
 187                 .output = 1, \
 188                 .channel = (_chan), \
 189                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 190                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 191                 .address = (_chan), \
 192                 .scan_type = { \
 193                         .realbits       = (_bits), \
 194                         .shift          = 16 - (_bits), \
 195                 }, \
 196                 .ext_info = ltc2632_ext_info, \
 197 }
 198
 199 #define DECLARE_LTC2632_CHANNELS(_name, _bits) \
 200         const struct iio_chan_spec _name ## _channels[] = { \
 201                 LTC2632_CHANNEL(0, _bits), \
 202                 LTC2632_CHANNEL(1, _bits), \
 203                 LTC2632_CHANNEL(2, _bits), \
 204                 LTC2632_CHANNEL(3, _bits), \
 205                 LTC2632_CHANNEL(4, _bits), \
 206                 LTC2632_CHANNEL(5, _bits), \
 207                 LTC2632_CHANNEL(6, _bits), \
 208                 LTC2632_CHANNEL(7, _bits), \
 209         }
 210
 211 static DECLARE_LTC2632_CHANNELS(ltc2632x12, 12);
 212 static DECLARE_LTC2632_CHANNELS(ltc2632x10, 10);
 213 static DECLARE_LTC2632_CHANNELS(ltc2632x8, 8);
 214
 215 static const struct ltc2632_chip_info ltc2632_chip_info_tbl[] = {
 216         [ID_LTC2632L12] = {
 217                 .channels       = ltc2632x12_channels,
 218                 .num_channels   = 2,
 219                 .vref_mv        = 2500,
 220         },
 221         [ID_LTC2632L10] = {
 222                 .channels       = ltc2632x10_channels,
 223                 .num_channels   = 2,
 224                 .vref_mv        = 2500,
 225         },
 226         [ID_LTC2632L8] =  {
 227                 .channels       = ltc2632x8_channels,
 228                 .num_channels   = 2,
 229                 .vref_mv        = 2500,
 230         },
 231         [ID_LTC2632H12] = {
 232                 .channels       = ltc2632x12_channels,
 233                 .num_channels   = 2,
 234                 .vref_mv        = 4096,
 235         },
 236         [ID_LTC2632H10] = {
 237                 .channels       = ltc2632x10_channels,
 238                 .num_channels   = 2,
 239                 .vref_mv        = 4096,
 240         },
 241         [ID_LTC2632H8] =  {
 242                 .channels       = ltc2632x8_channels,
 243                 .num_channels   = 2,
 244                 .vref_mv        = 4096,
 245         },
 246         [ID_LTC2634L12] = {
 247                 .channels       = ltc2632x12_channels,
 248                 .num_channels   = 4,
 249                 .vref_mv        = 2500,
 250         },
 251         [ID_LTC2634L10] = {
 252                 .channels       = ltc2632x10_channels,
 253                 .num_channels   = 4,
 254                 .vref_mv        = 2500,
 255         },
 256         [ID_LTC2634L8] =  {
 257                 .channels       = ltc2632x8_channels,
 258                 .num_channels   = 4,
 259                 .vref_mv        = 2500,
 260         },
 261         [ID_LTC2634H12] = {
 262                 .channels       = ltc2632x12_channels,
 263                 .num_channels   = 4,
 264                 .vref_mv        = 4096,
 265         },
 266         [ID_LTC2634H10] = {
 267                 .channels       = ltc2632x10_channels,
 268                 .num_channels   = 4,
 269                 .vref_mv        = 4096,
 270         },
 271         [ID_LTC2634H8] =  {
 272                 .channels       = ltc2632x8_channels,
 273                 .num_channels   = 4,
 274                 .vref_mv        = 4096,
 275         },
 276         [ID_LTC2636L12] = {
 277                 .channels       = ltc2632x12_channels,
 278                 .num_channels   = 8,
 279                 .vref_mv        = 2500,
 280         },
 281         [ID_LTC2636L10] = {
 282                 .channels       = ltc2632x10_channels,
 283                 .num_channels   = 8,
 284                 .vref_mv        = 2500,
 285         },
 286         [ID_LTC2636L8] =  {
 287                 .channels       = ltc2632x8_channels,
 288                 .num_channels   = 8,
 289                 .vref_mv        = 2500,
 290         },
 291         [ID_LTC2636H12] = {
 292                 .channels       = ltc2632x12_channels,
 293                 .num_channels   = 8,
 294                 .vref_mv        = 4096,
 295         },
 296         [ID_LTC2636H10] = {
 297                 .channels       = ltc2632x10_channels,
 298                 .num_channels   = 8,
 299                 .vref_mv        = 4096,
 300         },
 301         [ID_LTC2636H8] =  {
 302                 .channels       = ltc2632x8_channels,
 303                 .num_channels   = 8,
 304                 .vref_mv        = 4096,
 305         },
 306 };
 307
 308 static int ltc2632_probe(struct spi_device *spi)
 309 {
 310         struct ltc2632_state *st;
 311         struct iio_dev *indio_dev;
 312         struct ltc2632_chip_info *chip_info;
 313         int ret;
 314
 315         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 316         if (!indio_dev)
 317                 return -ENOMEM;
 318
 319         st = iio_priv(indio_dev);
 320
 321         spi_set_drvdata(spi, indio_dev);
 322         st->spi_dev = spi;
 323
 324         chip_info = (struct ltc2632_chip_info *)
 325                         spi_get_device_id(spi)->driver_data;
 326
 327         st->vref_reg = devm_regulator_get_optional(&spi->dev, "vref");
 328         if (PTR_ERR(st->vref_reg) == -ENODEV) {
 329                 /* use internal reference voltage */
 330                 st->vref_reg = NULL;
 331                 st->vref_mv = chip_info->vref_mv;
 332
 333                 ret = ltc2632_spi_write(spi, LTC2632_CMD_INTERNAL_REFER,
 334                                 0, 0, 0);
 335                 if (ret) {
 336                         dev_err(&spi->dev,
 337                                 "Set internal reference command failed, %d\n",
 338                                 ret);
 339                         return ret;
 340                 }
 341         } else if (IS_ERR(st->vref_reg)) {
 342                 dev_err(&spi->dev,
 343                                 "Error getting voltage reference regulator\n");
 344                 return PTR_ERR(st->vref_reg);
 345         } else {
 346                 /* use external reference voltage */
 347                 ret = regulator_enable(st->vref_reg);
 348                 if (ret) {
 349                         dev_err(&spi->dev,
 350                                 "enable reference regulator failed, %d\n",
 351                                 ret);
 352                         return ret;
 353                 }
 354                 st->vref_mv = regulator_get_voltage(st->vref_reg) / 1000;
 355
 356                 ret = ltc2632_spi_write(spi, LTC2632_CMD_EXTERNAL_REFER,
 357                                 0, 0, 0);
 358                 if (ret) {
 359                         dev_err(&spi->dev,
 360                                 "Set external reference command failed, %d\n",
 361                                 ret);
 362                         return ret;
 363                 }
 364         }
 365
 366         indio_dev->name = fwnode_get_name(dev_fwnode(&spi->dev)) ?: spi_get_device_id(spi)->name;
 367         indio_dev->info = &ltc2632_info;
 368         indio_dev->modes = INDIO_DIRECT_MODE;
 369         indio_dev->channels = chip_info->channels;
 370         indio_dev->num_channels = chip_info->num_channels;
 371
 372         return iio_device_register(indio_dev);
 373 }
 374
 375 static void ltc2632_remove(struct spi_device *spi)
 376 {
 377         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 378         struct ltc2632_state *st = iio_priv(indio_dev);
 379
 380         iio_device_unregister(indio_dev);
 381
 382         if (st->vref_reg)
 383                 regulator_disable(st->vref_reg);
 384 }
 385
 386 static const struct spi_device_id ltc2632_id[] = {
 387         { "ltc2632-l12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632L12] },
 388         { "ltc2632-l10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632L10] },
 389         { "ltc2632-l8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632L8] },
 390         { "ltc2632-h12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632H12] },
 391         { "ltc2632-h10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632H10] },
 392         { "ltc2632-h8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2632H8] },
 393         { "ltc2634-l12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634L12] },
 394         { "ltc2634-l10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634L10] },
 395         { "ltc2634-l8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634L8] },
 396         { "ltc2634-h12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634H12] },
 397         { "ltc2634-h10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634H10] },
 398         { "ltc2634-h8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2634H8] },
 399         { "ltc2636-l12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636L12] },
 400         { "ltc2636-l10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636L10] },
 401         { "ltc2636-l8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636L8] },
 402         { "ltc2636-h12", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636H12] },
 403         { "ltc2636-h10", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636H10] },
 404         { "ltc2636-h8", (kernel_ulong_t)&ltc2632_chip_info_tbl[ID_LTC2636H8] },
 405         {}
 406 };
 407 MODULE_DEVICE_TABLE(spi, ltc2632_id);
 408
 409 static const struct of_device_id ltc2632_of_match[] = {
 410         {
 411                 .compatible = "lltc,ltc2632-l12",
 412                 .data = &ltc2632_chip_info_tbl[ID_LTC2632L12]
 413         }, {
 414                 .compatible = "lltc,ltc2632-l10",
 415                 .data = &ltc2632_chip_info_tbl[ID_LTC2632L10]
 416         }, {
 417                 .compatible = "lltc,ltc2632-l8",
 418                 .data = &ltc2632_chip_info_tbl[ID_LTC2632L8]
 419         }, {
 420                 .compatible = "lltc,ltc2632-h12",
 421                 .data = &ltc2632_chip_info_tbl[ID_LTC2632H12]
 422         }, {
 423                 .compatible = "lltc,ltc2632-h10",
 424                 .data = &ltc2632_chip_info_tbl[ID_LTC2632H10]
 425         }, {
 426                 .compatible = "lltc,ltc2632-h8",
 427                 .data = &ltc2632_chip_info_tbl[ID_LTC2632H8]
 428         }, {
 429                 .compatible = "lltc,ltc2634-l12",
 430                 .data = &ltc2632_chip_info_tbl[ID_LTC2634L12]
 431         }, {
 432                 .compatible = "lltc,ltc2634-l10",
 433                 .data = &ltc2632_chip_info_tbl[ID_LTC2634L10]
 434         }, {
 435                 .compatible = "lltc,ltc2634-l8",
 436                 .data = &ltc2632_chip_info_tbl[ID_LTC2634L8]
 437         }, {
 438                 .compatible = "lltc,ltc2634-h12",
 439                 .data = &ltc2632_chip_info_tbl[ID_LTC2634H12]
 440         }, {
 441                 .compatible = "lltc,ltc2634-h10",
 442                 .data = &ltc2632_chip_info_tbl[ID_LTC2634H10]
 443         }, {
 444                 .compatible = "lltc,ltc2634-h8",
 445                 .data = &ltc2632_chip_info_tbl[ID_LTC2634H8]
 446         }, {
 447                 .compatible = "lltc,ltc2636-l12",
 448                 .data = &ltc2632_chip_info_tbl[ID_LTC2636L12]
 449         }, {
 450                 .compatible = "lltc,ltc2636-l10",
 451                 .data = &ltc2632_chip_info_tbl[ID_LTC2636L10]
 452         }, {
 453                 .compatible = "lltc,ltc2636-l8",
 454                 .data = &ltc2632_chip_info_tbl[ID_LTC2636L8]
 455         }, {
 456                 .compatible = "lltc,ltc2636-h12",
 457                 .data = &ltc2632_chip_info_tbl[ID_LTC2636H12]
 458         }, {
 459                 .compatible = "lltc,ltc2636-h10",
 460                 .data = &ltc2632_chip_info_tbl[ID_LTC2636H10]
 461         }, {
 462                 .compatible = "lltc,ltc2636-h8",
 463                 .data = &ltc2632_chip_info_tbl[ID_LTC2636H8]
 464         },
 465         {}
 466 };
 467 MODULE_DEVICE_TABLE(of, ltc2632_of_match);
 468
 469 static struct spi_driver ltc2632_driver = {
 470         .driver         = {
 471                 .name   = "ltc2632",
 472                 .of_match_table = ltc2632_of_match,
 473         },
 474         .probe          = ltc2632_probe,
 475         .remove         = ltc2632_remove,
 476         .id_table       = ltc2632_id,
 477 };
 478 module_spi_driver(ltc2632_driver);
 479
 480 MODULE_AUTHOR("Maxime Roussin-Belanger <maxime.roussinbelanger@gmail.com>");
 481 MODULE_DESCRIPTION("LTC2632 DAC SPI driver");
 482 MODULE_LICENSE("GPL v2");