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_separate = BIT(IIO_CHAN_INFO_RAW) |          \
  82                 BIT(IIO_CHAN_INFO_SCALE) |                      \
  83                 BIT(IIO_CHAN_INFO_CALIBSCALE) |                 \
  84                 BIT(IIO_CHAN_INFO_CALIBBIAS),                   \
  85         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET),  \
  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         int ret;
 139         struct spi_transfer t[] = {
 140                 {
 141                         .tx_buf = &st->data[0].d8[1],
 142                         .len = 3,
 143                         .cs_change = 1,
 144                 }, {
 145                         .rx_buf = &st->data[1].d8[1],
 146                         .len = 3,
 147                 },
 148         };
 149
 150         mutex_lock(&indio_dev->mlock);
 151
 152         st->data[0].d32 = cpu_to_be32((1 << 23) | (reg << 16));
 153
 154         ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
 155         if (ret >= 0)
 156                 *val = be32_to_cpu(st->data[1].d32) & 0xffff;
 157
 158         mutex_unlock(&indio_dev->mlock);
 159
 160         return ret;
 161 }
 162
 163 static int ad5764_chan_info_to_reg(struct iio_chan_spec const *chan, long info)
 164 {
 165         switch (info) {
 166         case 0:
 167                 return AD5764_REG_DATA(chan->address);
 168         case IIO_CHAN_INFO_CALIBBIAS:
 169                 return AD5764_REG_OFFSET(chan->address);
 170         case IIO_CHAN_INFO_CALIBSCALE:
 171                 return AD5764_REG_FINE_GAIN(chan->address);
 172         default:
 173                 break;
 174         }
 175
 176         return 0;
 177 }
 178
 179 static int ad5764_write_raw(struct iio_dev *indio_dev,
 180         struct iio_chan_spec const *chan, int val, int val2, long info)
 181 {
 182         const int max_val = (1 << chan->scan_type.realbits);
 183         unsigned int reg;
 184
 185         switch (info) {
 186         case IIO_CHAN_INFO_RAW:
 187                 if (val >= max_val || val < 0)
 188                         return -EINVAL;
 189                 val <<= chan->scan_type.shift;
 190                 break;
 191         case IIO_CHAN_INFO_CALIBBIAS:
 192                 if (val >= 128 || val < -128)
 193                         return -EINVAL;
 194                 break;
 195         case IIO_CHAN_INFO_CALIBSCALE:
 196                 if (val >= 32 || val < -32)
 197                         return -EINVAL;
 198                 break;
 199         default:
 200                 return -EINVAL;
 201         }
 202
 203         reg = ad5764_chan_info_to_reg(chan, info);
 204         return ad5764_write(indio_dev, reg, (u16)val);
 205 }
 206
 207 static int ad5764_get_channel_vref(struct ad5764_state *st,
 208         unsigned int channel)
 209 {
 210         if (st->chip_info->int_vref)
 211                 return st->chip_info->int_vref;
 212         else
 213                 return regulator_get_voltage(st->vref_reg[channel / 2].consumer);
 214 }
 215
 216 static int ad5764_read_raw(struct iio_dev *indio_dev,
 217         struct iio_chan_spec const *chan, int *val, int *val2, long info)
 218 {
 219         struct ad5764_state *st = iio_priv(indio_dev);
 220         unsigned long scale_uv;
 221         unsigned int reg;
 222         int vref;
 223         int ret;
 224
 225         switch (info) {
 226         case IIO_CHAN_INFO_RAW:
 227                 reg = AD5764_REG_DATA(chan->address);
 228                 ret = ad5764_read(indio_dev, reg, val);
 229                 if (ret < 0)
 230                         return ret;
 231                 *val >>= chan->scan_type.shift;
 232                 return IIO_VAL_INT;
 233         case IIO_CHAN_INFO_CALIBBIAS:
 234                 reg = AD5764_REG_OFFSET(chan->address);
 235                 ret = ad5764_read(indio_dev, reg, val);
 236                 if (ret < 0)
 237                         return ret;
 238                 *val = sign_extend32(*val, 7);
 239                 return IIO_VAL_INT;
 240         case IIO_CHAN_INFO_CALIBSCALE:
 241                 reg = AD5764_REG_FINE_GAIN(chan->address);
 242                 ret = ad5764_read(indio_dev, reg, val);
 243                 if (ret < 0)
 244                         return ret;
 245                 *val = sign_extend32(*val, 5);
 246                 return IIO_VAL_INT;
 247         case IIO_CHAN_INFO_SCALE:
 248                 /* vout = 4 * vref + ((dac_code / 65535) - 0.5) */
 249                 vref = ad5764_get_channel_vref(st, chan->channel);
 250                 if (vref < 0)
 251                         return vref;
 252
 253                 scale_uv = (vref * 4 * 100) >> chan->scan_type.realbits;
 254                 *val = scale_uv / 100000;
 255                 *val2 = (scale_uv % 100000) * 10;
 256                 return IIO_VAL_INT_PLUS_MICRO;
 257         case IIO_CHAN_INFO_OFFSET:
 258                 *val = -(1 << chan->scan_type.realbits) / 2;
 259                 return IIO_VAL_INT;
 260         }
 261
 262         return -EINVAL;
 263 }
 264
 265 static const struct iio_info ad5764_info = {
 266         .read_raw = ad5764_read_raw,
 267         .write_raw = ad5764_write_raw,
 268         .driver_module = THIS_MODULE,
 269 };
 270
 271 static int ad5764_probe(struct spi_device *spi)
 272 {
 273         enum ad5764_type type = spi_get_device_id(spi)->driver_data;
 274         struct iio_dev *indio_dev;
 275         struct ad5764_state *st;
 276         int ret;
 277
 278         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 279         if (indio_dev == NULL) {
 280                 dev_err(&spi->dev, "Failed to allocate iio device\n");
 281                 return -ENOMEM;
 282         }
 283
 284         st = iio_priv(indio_dev);
 285         spi_set_drvdata(spi, indio_dev);
 286
 287         st->spi = spi;
 288         st->chip_info = &ad5764_chip_infos[type];
 289
 290         indio_dev->dev.parent = &spi->dev;
 291         indio_dev->name = spi_get_device_id(spi)->name;
 292         indio_dev->info = &ad5764_info;
 293         indio_dev->modes = INDIO_DIRECT_MODE;
 294         indio_dev->num_channels = AD5764_NUM_CHANNELS;
 295         indio_dev->channels = st->chip_info->channels;
 296
 297         if (st->chip_info->int_vref == 0) {
 298                 st->vref_reg[0].supply = "vrefAB";
 299                 st->vref_reg[1].supply = "vrefCD";
 300
 301                 ret = devm_regulator_bulk_get(&st->spi->dev,
 302                         ARRAY_SIZE(st->vref_reg), st->vref_reg);
 303                 if (ret) {
 304                         dev_err(&spi->dev, "Failed to request vref regulators: %d\n",
 305                                 ret);
 306                         return ret;
 307                 }
 308
 309                 ret = regulator_bulk_enable(ARRAY_SIZE(st->vref_reg),
 310                         st->vref_reg);
 311                 if (ret) {
 312                         dev_err(&spi->dev, "Failed to enable vref regulators: %d\n",
 313                                 ret);
 314                         return ret;
 315                 }
 316         }
 317
 318         ret = iio_device_register(indio_dev);
 319         if (ret) {
 320                 dev_err(&spi->dev, "Failed to register iio device: %d\n", ret);
 321                 goto error_disable_reg;
 322         }
 323
 324         return 0;
 325
 326 error_disable_reg:
 327         if (st->chip_info->int_vref == 0)
 328                 regulator_bulk_disable(ARRAY_SIZE(st->vref_reg), st->vref_reg);
 329         return ret;
 330 }
 331
 332 static int ad5764_remove(struct spi_device *spi)
 333 {
 334         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 335         struct ad5764_state *st = iio_priv(indio_dev);
 336
 337         iio_device_unregister(indio_dev);
 338
 339         if (st->chip_info->int_vref == 0)
 340                 regulator_bulk_disable(ARRAY_SIZE(st->vref_reg), st->vref_reg);
 341
 342         return 0;
 343 }
 344
 345 static const struct spi_device_id ad5764_ids[] = {
 346         { "ad5744", ID_AD5744 },
 347         { "ad5744r", ID_AD5744R },
 348         { "ad5764", ID_AD5764 },
 349         { "ad5764r", ID_AD5764R },
 350         { }
 351 };
 352 MODULE_DEVICE_TABLE(spi, ad5764_ids);
 353
 354 static struct spi_driver ad5764_driver = {
 355         .driver = {
 356                 .name = "ad5764",
 357                 .owner = THIS_MODULE,
 358         },
 359         .probe = ad5764_probe,
 360         .remove = ad5764_remove,
 361         .id_table = ad5764_ids,
 362 };
 363 module_spi_driver(ad5764_driver);
 364
 365 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
 366 MODULE_DESCRIPTION("Analog Devices AD5744/AD5744R/AD5764/AD5764R DAC");
 367 MODULE_LICENSE("GPL v2");