drivers/iio/dac/ad5764.c

   1 /*
   2  * Analog devices AD5764, AD5764R, AD5744, AD5744R quad-channel
   3  * Digital to Analog Converters driver
   4  *
   5  * Copyright 2011 Analog Devices Inc.
   6  *
   7  * Licensed under the GPL-2.
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/err.h>
  12 #include <linux/module.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
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/sysfs.h>
  21
  22 #define AD5764_REG_SF_NOP                       0x0
  23 #define AD5764_REG_SF_CONFIG                    0x1
  24 #define AD5764_REG_SF_CLEAR                     0x4
  25 #define AD5764_REG_SF_LOAD                      0x5
  26 #define AD5764_REG_DATA(x)                      ((2 << 3) | (x))
  27 #define AD5764_REG_COARSE_GAIN(x)               ((3 << 3) | (x))
  28 #define AD5764_REG_FINE_GAIN(x)                 ((4 << 3) | (x))
  29 #define AD5764_REG_OFFSET(x)                    ((5 << 3) | (x))
  30
  31 #define AD5764_NUM_CHANNELS 4
  32
  33 /**
  34  * struct ad5764_chip_info - chip specific information
  35  * @int_vref:   Value of the internal reference voltage in uV - 0 if external
  36  *              reference voltage is used
  37  * @channel     channel specification
  38 */
  39
  40 struct ad5764_chip_info {
  41         unsigned long int_vref;
  42         const struct iio_chan_spec *channels;
  43 };
  44
  45 /**
  46  * struct ad5764_state - driver instance specific data
  47  * @spi:                spi_device
  48  * @chip_info:          chip info
  49  * @vref_reg:           vref supply regulators
  50  * @data:               spi transfer buffers
  51  */
  52
  53 struct ad5764_state {
  54         struct spi_device               *spi;
  55         const struct ad5764_chip_info   *chip_info;
  56         struct regulator_bulk_data      vref_reg[2];
  57
  58         /*
  59          * DMA (thus cache coherency maintenance) requires the
  60          * transfer buffers to live in their own cache lines.
  61          */
  62         union {
  63                 __be32 d32;
  64                 u8 d8[4];
  65         } data[2] ____cacheline_aligned;
  66 };
  67
  68 enum ad5764_type {
  69         ID_AD5744,
  70         ID_AD5744R,
  71         ID_AD5764,
  72         ID_AD5764R,
  73 };
  74
  75 #define AD5764_CHANNEL(_chan, _bits) {                          \
  76         .type = IIO_VOLTAGE,                                    \
  77         .indexed = 1,                                           \
  78         .output = 1,                                            \
  79         .channel = (_chan),                                     \
  80         .address = (_chan),                                     \
  81         .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |           \
  82                 IIO_CHAN_INFO_OFFSET_SHARED_BIT |               \
  83                 IIO_CHAN_INFO_SCALE_SEPARATE_BIT |              \
  84                 IIO_CHAN_INFO_CALIBSCALE_SEPARATE_BIT |         \
  85                 IIO_CHAN_INFO_CALIBBIAS_SEPARATE_BIT,           \
  86         .scan_type = IIO_ST('u', (_bits), 16, 16 - (_bits))     \
  87 }
  88
  89 #define DECLARE_AD5764_CHANNELS(_name, _bits) \
  90 const struct iio_chan_spec _name##_channels[] = { \
  91         AD5764_CHANNEL(0, (_bits)), \
  92         AD5764_CHANNEL(1, (_bits)), \
  93         AD5764_CHANNEL(2, (_bits)), \
  94         AD5764_CHANNEL(3, (_bits)), \
  95 };
  96
  97 static DECLARE_AD5764_CHANNELS(ad5764, 16);
  98 static DECLARE_AD5764_CHANNELS(ad5744, 14);
  99
 100 static const struct ad5764_chip_info ad5764_chip_infos[] = {
 101         [ID_AD5744] = {
 102                 .int_vref = 0,
 103                 .channels = ad5744_channels,
 104         },
 105         [ID_AD5744R] = {
 106                 .int_vref = 5000000,
 107                 .channels = ad5744_channels,
 108         },
 109         [ID_AD5764] = {
 110                 .int_vref = 0,
 111                 .channels = ad5764_channels,
 112         },
 113         [ID_AD5764R] = {
 114                 .int_vref = 5000000,
 115                 .channels = ad5764_channels,
 116         },
 117 };
 118
 119 static int ad5764_write(struct iio_dev *indio_dev, unsigned int reg,
 120         unsigned int val)
 121 {
 122         struct ad5764_state *st = iio_priv(indio_dev);
 123         int ret;
 124
 125         mutex_lock(&indio_dev->mlock);
 126         st->data[0].d32 = cpu_to_be32((reg << 16) | val);
 127
 128         ret = spi_write(st->spi, &st->data[0].d8[1], 3);
 129         mutex_unlock(&indio_dev->mlock);
 130
 131         return ret;
 132 }
 133
 134 static int ad5764_read(struct iio_dev *indio_dev, unsigned int reg,
 135         unsigned int *val)
 136 {
 137         struct ad5764_state *st = iio_priv(indio_dev);
 138         struct spi_message m;
 139         int ret;
 140         struct spi_transfer t[] = {
 141                 {
 142                         .tx_buf = &st->data[0].d8[1],
 143                         .len = 3,
 144                         .cs_change = 1,
 145                 }, {
 146                         .rx_buf = &st->data[1].d8[1],
 147                         .len = 3,
 148                 },
 149         };
 150
 151         spi_message_init(&m);
 152         spi_message_add_tail(&t[0], &m);
 153         spi_message_add_tail(&t[1], &m);
 154
 155         mutex_lock(&indio_dev->mlock);
 156
 157         st->data[0].d32 = cpu_to_be32((1 << 23) | (reg << 16));
 158
 159         ret = spi_sync(st->spi, &m);
 160         if (ret >= 0)
 161                 *val = be32_to_cpu(st->data[1].d32) & 0xffff;
 162
 163         mutex_unlock(&indio_dev->mlock);
 164
 165         return ret;
 166 }
 167
 168 static int ad5764_chan_info_to_reg(struct iio_chan_spec const *chan, long info)
 169 {
 170         switch (info) {
 171         case 0:
 172                 return AD5764_REG_DATA(chan->address);
 173         case IIO_CHAN_INFO_CALIBBIAS:
 174                 return AD5764_REG_OFFSET(chan->address);
 175         case IIO_CHAN_INFO_CALIBSCALE:
 176                 return AD5764_REG_FINE_GAIN(chan->address);
 177         default:
 178                 break;
 179         }
 180
 181         return 0;
 182 }
 183
 184 static int ad5764_write_raw(struct iio_dev *indio_dev,
 185         struct iio_chan_spec const *chan, int val, int val2, long info)
 186 {
 187         const int max_val = (1 << chan->scan_type.realbits);
 188         unsigned int reg;
 189
 190         switch (info) {
 191         case IIO_CHAN_INFO_RAW:
 192                 if (val >= max_val || val < 0)
 193                         return -EINVAL;
 194                 val <<= chan->scan_type.shift;
 195                 break;
 196         case IIO_CHAN_INFO_CALIBBIAS:
 197                 if (val >= 128 || val < -128)
 198                         return -EINVAL;
 199                 break;
 200         case IIO_CHAN_INFO_CALIBSCALE:
 201                 if (val >= 32 || val < -32)
 202                         return -EINVAL;
 203                 break;
 204         default:
 205                 return -EINVAL;
 206         }
 207
 208         reg = ad5764_chan_info_to_reg(chan, info);
 209         return ad5764_write(indio_dev, reg, (u16)val);
 210 }
 211
 212 static int ad5764_get_channel_vref(struct ad5764_state *st,
 213         unsigned int channel)
 214 {
 215         if (st->chip_info->int_vref)
 216                 return st->chip_info->int_vref;
 217         else
 218                 return regulator_get_voltage(st->vref_reg[channel / 2].consumer);
 219 }
 220
 221 static int ad5764_read_raw(struct iio_dev *indio_dev,
 222         struct iio_chan_spec const *chan, int *val, int *val2, long info)
 223 {
 224         struct ad5764_state *st = iio_priv(indio_dev);
 225         unsigned long scale_uv;
 226         unsigned int reg;
 227         int vref;
 228         int ret;
 229
 230         switch (info) {
 231         case IIO_CHAN_INFO_RAW:
 232                 reg = AD5764_REG_DATA(chan->address);
 233                 ret = ad5764_read(indio_dev, reg, val);
 234                 if (ret < 0)
 235                         return ret;
 236                 *val >>= chan->scan_type.shift;
 237                 return IIO_VAL_INT;
 238         case IIO_CHAN_INFO_CALIBBIAS:
 239                 reg = AD5764_REG_OFFSET(chan->address);
 240                 ret = ad5764_read(indio_dev, reg, val);
 241                 if (ret < 0)
 242                         return ret;
 243                 *val = sign_extend32(*val, 7);
 244                 return IIO_VAL_INT;
 245         case IIO_CHAN_INFO_CALIBSCALE:
 246                 reg = AD5764_REG_FINE_GAIN(chan->address);
 247                 ret = ad5764_read(indio_dev, reg, val);
 248                 if (ret < 0)
 249                         return ret;
 250                 *val = sign_extend32(*val, 5);
 251                 return IIO_VAL_INT;
 252         case IIO_CHAN_INFO_SCALE:
 253                 /* vout = 4 * vref + ((dac_code / 65535) - 0.5) */
 254                 vref = ad5764_get_channel_vref(st, chan->channel);
 255                 if (vref < 0)
 256                         return vref;
 257
 258                 scale_uv = (vref * 4 * 100) >> chan->scan_type.realbits;
 259                 *val = scale_uv / 100000;
 260                 *val2 = (scale_uv % 100000) * 10;
 261                 return IIO_VAL_INT_PLUS_MICRO;
 262         case IIO_CHAN_INFO_OFFSET:
 263                 *val = -(1 << chan->scan_type.realbits) / 2;
 264                 return IIO_VAL_INT;
 265         }
 266
 267         return -EINVAL;
 268 }
 269
 270 static const struct iio_info ad5764_info = {
 271         .read_raw = ad5764_read_raw,
 272         .write_raw = ad5764_write_raw,
 273         .driver_module = THIS_MODULE,
 274 };
 275
 276 static int ad5764_probe(struct spi_device *spi)
 277 {
 278         enum ad5764_type type = spi_get_device_id(spi)->driver_data;
 279         struct iio_dev *indio_dev;
 280         struct ad5764_state *st;
 281         int ret;
 282
 283         indio_dev = iio_device_alloc(sizeof(*st));
 284         if (indio_dev == NULL) {
 285                 dev_err(&spi->dev, "Failed to allocate iio device\n");
 286                 return -ENOMEM;
 287         }
 288
 289         st = iio_priv(indio_dev);
 290         spi_set_drvdata(spi, indio_dev);
 291
 292         st->spi = spi;
 293         st->chip_info = &ad5764_chip_infos[type];
 294
 295         indio_dev->dev.parent = &spi->dev;
 296         indio_dev->name = spi_get_device_id(spi)->name;
 297         indio_dev->info = &ad5764_info;
 298         indio_dev->modes = INDIO_DIRECT_MODE;
 299         indio_dev->num_channels = AD5764_NUM_CHANNELS;
 300         indio_dev->channels = st->chip_info->channels;
 301
 302         if (st->chip_info->int_vref == 0) {
 303                 st->vref_reg[0].supply = "vrefAB";
 304                 st->vref_reg[1].supply = "vrefCD";
 305
 306                 ret = regulator_bulk_get(&st->spi->dev,
 307                         ARRAY_SIZE(st->vref_reg), st->vref_reg);
 308                 if (ret) {
 309                         dev_err(&spi->dev, "Failed to request vref regulators: %d\n",
 310                                 ret);
 311                         goto error_free;
 312                 }
 313
 314                 ret = regulator_bulk_enable(ARRAY_SIZE(st->vref_reg),
 315                         st->vref_reg);
 316                 if (ret) {
 317                         dev_err(&spi->dev, "Failed to enable vref regulators: %d\n",
 318                                 ret);
 319                         goto error_free_reg;
 320                 }
 321         }
 322
 323         ret = iio_device_register(indio_dev);
 324         if (ret) {
 325                 dev_err(&spi->dev, "Failed to register iio device: %d\n", ret);
 326                 goto error_disable_reg;
 327         }
 328
 329         return 0;
 330
 331 error_disable_reg:
 332         if (st->chip_info->int_vref == 0)
 333                 regulator_bulk_disable(ARRAY_SIZE(st->vref_reg), st->vref_reg);
 334 error_free_reg:
 335         if (st->chip_info->int_vref == 0)
 336                 regulator_bulk_free(ARRAY_SIZE(st->vref_reg), st->vref_reg);
 337 error_free:
 338         iio_device_free(indio_dev);
 339
 340         return ret;
 341 }
 342
 343 static int ad5764_remove(struct spi_device *spi)
 344 {
 345         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 346         struct ad5764_state *st = iio_priv(indio_dev);
 347
 348         iio_device_unregister(indio_dev);
 349
 350         if (st->chip_info->int_vref == 0) {
 351                 regulator_bulk_disable(ARRAY_SIZE(st->vref_reg), st->vref_reg);
 352                 regulator_bulk_free(ARRAY_SIZE(st->vref_reg), st->vref_reg);
 353         }
 354
 355         iio_device_free(indio_dev);
 356
 357         return 0;
 358 }
 359
 360 static const struct spi_device_id ad5764_ids[] = {
 361         { "ad5744", ID_AD5744 },
 362         { "ad5744r", ID_AD5744R },
 363         { "ad5764", ID_AD5764 },
 364         { "ad5764r", ID_AD5764R },
 365         { }
 366 };
 367 MODULE_DEVICE_TABLE(spi, ad5764_ids);
 368
 369 static struct spi_driver ad5764_driver = {
 370         .driver = {
 371                 .name = "ad5764",
 372                 .owner = THIS_MODULE,
 373         },
 374         .probe = ad5764_probe,
 375         .remove = ad5764_remove,
 376         .id_table = ad5764_ids,
 377 };
 378 module_spi_driver(ad5764_driver);
 379
 380 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 381 MODULE_DESCRIPTION("Analog Devices AD5744/AD5744R/AD5764/AD5764R DAC");
 382 MODULE_LICENSE("GPL v2");