drivers/iio/dac/ad5761.c

   1 /*
   2  * AD5721, AD5721R, AD5761, AD5761R, Voltage Output Digital to Analog Converter
   3  *
   4  * Copyright 2016 Qtechnology A/S
   5  * 2016 Ricardo Ribalda <ricardo.ribalda@gmail.com>
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/bitops.h>
  13 #include <linux/iio/iio.h>
  14 #include <linux/iio/sysfs.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/platform_data/ad5761.h>
  17
  18 #define AD5761_ADDR(addr)               ((addr & 0xf) << 16)
  19 #define AD5761_ADDR_NOOP                0x0
  20 #define AD5761_ADDR_DAC_WRITE           0x3
  21 #define AD5761_ADDR_CTRL_WRITE_REG      0x4
  22 #define AD5761_ADDR_SW_DATA_RESET       0x7
  23 #define AD5761_ADDR_DAC_READ            0xb
  24 #define AD5761_ADDR_CTRL_READ_REG       0xc
  25 #define AD5761_ADDR_SW_FULL_RESET       0xf
  26
  27 #define AD5761_CTRL_USE_INTVREF         BIT(5)
  28 #define AD5761_CTRL_ETS                 BIT(6)
  29
  30 /**
  31  * struct ad5761_chip_info - chip specific information
  32  * @int_vref:   Value of the internal reference voltage in mV - 0 if external
  33  *              reference voltage is used
  34  * @channel:    channel specification
  35 */
  36
  37 struct ad5761_chip_info {
  38         unsigned long int_vref;
  39         const struct iio_chan_spec channel;
  40 };
  41
  42 struct ad5761_range_params {
  43         int m;
  44         int c;
  45 };
  46
  47 enum ad5761_supported_device_ids {
  48         ID_AD5721,
  49         ID_AD5721R,
  50         ID_AD5761,
  51         ID_AD5761R,
  52 };
  53
  54 /**
  55  * struct ad5761_state - driver instance specific data
  56  * @spi:                spi_device
  57  * @vref_reg:           reference voltage regulator
  58  * @use_intref:         true when the internal voltage reference is used
  59  * @vref:               actual voltage reference in mVolts
  60  * @range:              output range mode used
  61  * @data:               cache aligned spi buffer
  62  */
  63 struct ad5761_state {
  64         struct spi_device               *spi;
  65         struct regulator                *vref_reg;
  66
  67         bool use_intref;
  68         int vref;
  69         enum ad5761_voltage_range range;
  70
  71         /*
  72          * DMA (thus cache coherency maintenance) requires the
  73          * transfer buffers to live in their own cache lines.
  74          */
  75         union {
  76                 __be32 d32;
  77                 u8 d8[4];
  78         } data[3] ____cacheline_aligned;
  79 };
  80
  81 static const struct ad5761_range_params ad5761_range_params[] = {
  82         [AD5761_VOLTAGE_RANGE_M10V_10V] = {
  83                 .m = 80,
  84                 .c = 40,
  85         },
  86         [AD5761_VOLTAGE_RANGE_0V_10V] = {
  87                 .m = 40,
  88                 .c = 0,
  89         },
  90         [AD5761_VOLTAGE_RANGE_M5V_5V] = {
  91                 .m = 40,
  92                 .c = 20,
  93         },
  94         [AD5761_VOLTAGE_RANGE_0V_5V] = {
  95                 .m = 20,
  96                 .c = 0,
  97         },
  98         [AD5761_VOLTAGE_RANGE_M2V5_7V5] = {
  99                 .m = 40,
 100                 .c = 10,
 101         },
 102         [AD5761_VOLTAGE_RANGE_M3V_3V] = {
 103                 .m = 24,
 104                 .c = 12,
 105         },
 106         [AD5761_VOLTAGE_RANGE_0V_16V] = {
 107                 .m = 64,
 108                 .c = 0,
 109         },
 110         [AD5761_VOLTAGE_RANGE_0V_20V] = {
 111                 .m = 80,
 112                 .c = 0,
 113         },
 114 };
 115
 116 static int _ad5761_spi_write(struct ad5761_state *st, u8 addr, u16 val)
 117 {
 118         st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr) | val);
 119
 120         return spi_write(st->spi, &st->data[0].d8[1], 3);
 121 }
 122
 123 static int ad5761_spi_write(struct iio_dev *indio_dev, u8 addr, u16 val)
 124 {
 125         struct ad5761_state *st = iio_priv(indio_dev);
 126         int ret;
 127
 128         mutex_lock(&indio_dev->mlock);
 129         ret = _ad5761_spi_write(st, addr, val);
 130         mutex_unlock(&indio_dev->mlock);
 131
 132         return ret;
 133 }
 134
 135 static int _ad5761_spi_read(struct ad5761_state *st, u8 addr, u16 *val)
 136 {
 137         int ret;
 138         struct spi_transfer xfers[] = {
 139                 {
 140                         .tx_buf = &st->data[0].d8[1],
 141                         .bits_per_word = 8,
 142                         .len = 3,
 143                         .cs_change = true,
 144                 }, {
 145                         .tx_buf = &st->data[1].d8[1],
 146                         .rx_buf = &st->data[2].d8[1],
 147                         .bits_per_word = 8,
 148                         .len = 3,
 149                 },
 150         };
 151
 152         st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr));
 153         st->data[1].d32 = cpu_to_be32(AD5761_ADDR(AD5761_ADDR_NOOP));
 154
 155         ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
 156
 157         *val = be32_to_cpu(st->data[2].d32);
 158
 159         return ret;
 160 }
 161
 162 static int ad5761_spi_read(struct iio_dev *indio_dev, u8 addr, u16 *val)
 163 {
 164         struct ad5761_state *st = iio_priv(indio_dev);
 165         int ret;
 166
 167         mutex_lock(&indio_dev->mlock);
 168         ret = _ad5761_spi_read(st, addr, val);
 169         mutex_unlock(&indio_dev->mlock);
 170
 171         return ret;
 172 }
 173
 174 static int ad5761_spi_set_range(struct ad5761_state *st,
 175                                 enum ad5761_voltage_range range)
 176 {
 177         u16 aux;
 178         int ret;
 179
 180         aux = (range & 0x7) | AD5761_CTRL_ETS;
 181
 182         if (st->use_intref)
 183                 aux |= AD5761_CTRL_USE_INTVREF;
 184
 185         ret = _ad5761_spi_write(st, AD5761_ADDR_SW_FULL_RESET, 0);
 186         if (ret)
 187                 return ret;
 188
 189         ret = _ad5761_spi_write(st, AD5761_ADDR_CTRL_WRITE_REG, aux);
 190         if (ret)
 191                 return ret;
 192
 193         st->range = range;
 194
 195         return 0;
 196 }
 197
 198 static int ad5761_read_raw(struct iio_dev *indio_dev,
 199                            struct iio_chan_spec const *chan,
 200                            int *val,
 201                            int *val2,
 202                            long mask)
 203 {
 204         struct ad5761_state *st;
 205         int ret;
 206         u16 aux;
 207
 208         switch (mask) {
 209         case IIO_CHAN_INFO_RAW:
 210                 ret = ad5761_spi_read(indio_dev, AD5761_ADDR_DAC_READ, &aux);
 211                 if (ret)
 212                         return ret;
 213                 *val = aux >> chan->scan_type.shift;
 214                 return IIO_VAL_INT;
 215         case IIO_CHAN_INFO_SCALE:
 216                 st = iio_priv(indio_dev);
 217                 *val = st->vref * ad5761_range_params[st->range].m;
 218                 *val /= 10;
 219                 *val2 = chan->scan_type.realbits;
 220                 return IIO_VAL_FRACTIONAL_LOG2;
 221         case IIO_CHAN_INFO_OFFSET:
 222                 st = iio_priv(indio_dev);
 223                 *val = -(1 << chan->scan_type.realbits);
 224                 *val *= ad5761_range_params[st->range].c;
 225                 *val /= ad5761_range_params[st->range].m;
 226                 return IIO_VAL_INT;
 227         default:
 228                 return -EINVAL;
 229         }
 230 }
 231
 232 static int ad5761_write_raw(struct iio_dev *indio_dev,
 233                             struct iio_chan_spec const *chan,
 234                             int val,
 235                             int val2,
 236                             long mask)
 237 {
 238         u16 aux;
 239
 240         if (mask != IIO_CHAN_INFO_RAW)
 241                 return -EINVAL;
 242
 243         if (val2 || (val << chan->scan_type.shift) > 0xffff || val < 0)
 244                 return -EINVAL;
 245
 246         aux = val << chan->scan_type.shift;
 247
 248         return ad5761_spi_write(indio_dev, AD5761_ADDR_DAC_WRITE, aux);
 249 }
 250
 251 static const struct iio_info ad5761_info = {
 252         .read_raw = &ad5761_read_raw,
 253         .write_raw = &ad5761_write_raw,
 254         .driver_module = THIS_MODULE,
 255 };
 256
 257 #define AD5761_CHAN(_bits) {                            \
 258         .type = IIO_VOLTAGE,                            \
 259         .output = 1,                                    \
 260         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 261         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
 262                 BIT(IIO_CHAN_INFO_OFFSET),              \
 263         .scan_type = {                                  \
 264                 .sign = 'u',                            \
 265                 .realbits = (_bits),                    \
 266                 .storagebits = 16,                      \
 267                 .shift = 16 - (_bits),                  \
 268         },                                              \
 269 }
 270
 271 static const struct ad5761_chip_info ad5761_chip_infos[] = {
 272         [ID_AD5721] = {
 273                 .int_vref = 0,
 274                 .channel = AD5761_CHAN(12),
 275         },
 276         [ID_AD5721R] = {
 277                 .int_vref = 2500,
 278                 .channel = AD5761_CHAN(12),
 279         },
 280         [ID_AD5761] = {
 281                 .int_vref = 0,
 282                 .channel = AD5761_CHAN(16),
 283         },
 284         [ID_AD5761R] = {
 285                 .int_vref = 2500,
 286                 .channel = AD5761_CHAN(16),
 287         },
 288 };
 289
 290 static int ad5761_get_vref(struct ad5761_state *st,
 291                            const struct ad5761_chip_info *chip_info)
 292 {
 293         int ret;
 294
 295         st->vref_reg = devm_regulator_get_optional(&st->spi->dev, "vref");
 296         if (PTR_ERR(st->vref_reg) == -ENODEV) {
 297                 /* Use Internal regulator */
 298                 if (!chip_info->int_vref) {
 299                         dev_err(&st->spi->dev,
 300                                 "Voltage reference not found\n");
 301                         return -EIO;
 302                 }
 303
 304                 st->use_intref = true;
 305                 st->vref = chip_info->int_vref;
 306                 return 0;
 307         }
 308
 309         if (IS_ERR(st->vref_reg)) {
 310                 dev_err(&st->spi->dev,
 311                         "Error getting voltage reference regulator\n");
 312                 return PTR_ERR(st->vref_reg);
 313         }
 314
 315         ret = regulator_enable(st->vref_reg);
 316         if (ret) {
 317                 dev_err(&st->spi->dev,
 318                          "Failed to enable voltage reference\n");
 319                 return ret;
 320         }
 321
 322         ret = regulator_get_voltage(st->vref_reg);
 323         if (ret < 0) {
 324                 dev_err(&st->spi->dev,
 325                          "Failed to get voltage reference value\n");
 326                 goto disable_regulator_vref;
 327         }
 328
 329         if (ret < 2000000 || ret > 3000000) {
 330                 dev_warn(&st->spi->dev,
 331                          "Invalid external voltage ref. value %d uV\n", ret);
 332                 ret = -EIO;
 333                 goto disable_regulator_vref;
 334         }
 335
 336         st->vref = ret / 1000;
 337         st->use_intref = false;
 338
 339         return 0;
 340
 341 disable_regulator_vref:
 342         regulator_disable(st->vref_reg);
 343         st->vref_reg = NULL;
 344         return ret;
 345 }
 346
 347 static int ad5761_probe(struct spi_device *spi)
 348 {
 349         struct iio_dev *iio_dev;
 350         struct ad5761_state *st;
 351         int ret;
 352         const struct ad5761_chip_info *chip_info =
 353                 &ad5761_chip_infos[spi_get_device_id(spi)->driver_data];
 354         enum ad5761_voltage_range voltage_range = AD5761_VOLTAGE_RANGE_0V_5V;
 355         struct ad5761_platform_data *pdata = dev_get_platdata(&spi->dev);
 356
 357         iio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 358         if (!iio_dev)
 359                 return -ENOMEM;
 360
 361         st = iio_priv(iio_dev);
 362
 363         st->spi = spi;
 364         spi_set_drvdata(spi, iio_dev);
 365
 366         ret = ad5761_get_vref(st, chip_info);
 367         if (ret)
 368                 return ret;
 369
 370         if (pdata)
 371                 voltage_range = pdata->voltage_range;
 372
 373         ret = ad5761_spi_set_range(st, voltage_range);
 374         if (ret)
 375                 goto disable_regulator_err;
 376
 377         iio_dev->dev.parent = &spi->dev;
 378         iio_dev->info = &ad5761_info;
 379         iio_dev->modes = INDIO_DIRECT_MODE;
 380         iio_dev->channels = &chip_info->channel;
 381         iio_dev->num_channels = 1;
 382         iio_dev->name = spi_get_device_id(st->spi)->name;
 383         ret = iio_device_register(iio_dev);
 384         if (ret)
 385                 goto disable_regulator_err;
 386
 387         return 0;
 388
 389 disable_regulator_err:
 390         if (!IS_ERR_OR_NULL(st->vref_reg))
 391                 regulator_disable(st->vref_reg);
 392
 393         return ret;
 394 }
 395
 396 static int ad5761_remove(struct spi_device *spi)
 397 {
 398         struct iio_dev *iio_dev = spi_get_drvdata(spi);
 399         struct ad5761_state *st = iio_priv(iio_dev);
 400
 401         iio_device_unregister(iio_dev);
 402
 403         if (!IS_ERR_OR_NULL(st->vref_reg))
 404                 regulator_disable(st->vref_reg);
 405
 406         return 0;
 407 }
 408
 409 static const struct spi_device_id ad5761_id[] = {
 410         {"ad5721", ID_AD5721},
 411         {"ad5721r", ID_AD5721R},
 412         {"ad5761", ID_AD5761},
 413         {"ad5761r", ID_AD5761R},
 414         {}
 415 };
 416 MODULE_DEVICE_TABLE(spi, ad5761_id);
 417
 418 static struct spi_driver ad5761_driver = {
 419         .driver = {
 420                    .name = "ad5761",
 421                    },
 422         .probe = ad5761_probe,
 423         .remove = ad5761_remove,
 424         .id_table = ad5761_id,
 425 };
 426 module_spi_driver(ad5761_driver);
 427
 428 MODULE_AUTHOR("Ricardo Ribalda <ricardo.ribalda@gmail.com>");
 429 MODULE_DESCRIPTION("Analog Devices AD5721, AD5721R, AD5761, AD5761R driver");
 430 MODULE_LICENSE("GPL v2");