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