drivers/iio/dac/ad5686.c

   1 /*
   2  * AD5686R, AD5685R, AD5684R Digital to analog converters  driver
   3  *
   4  * Copyright 2011 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/fs.h>
  11 #include <linux/device.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 AD5686_DAC_CHANNELS                     4
  23
  24 #define AD5686_ADDR(x)                          ((x) << 16)
  25 #define AD5686_CMD(x)                           ((x) << 20)
  26
  27 #define AD5686_ADDR_DAC(chan)           (0x1 << (chan))
  28 #define AD5686_ADDR_ALL_DAC                     0xF
  29
  30 #define AD5686_CMD_NOOP                         0x0
  31 #define AD5686_CMD_WRITE_INPUT_N                0x1
  32 #define AD5686_CMD_UPDATE_DAC_N                 0x2
  33 #define AD5686_CMD_WRITE_INPUT_N_UPDATE_N       0x3
  34 #define AD5686_CMD_POWERDOWN_DAC                0x4
  35 #define AD5686_CMD_LDAC_MASK                    0x5
  36 #define AD5686_CMD_RESET                        0x6
  37 #define AD5686_CMD_INTERNAL_REFER_SETUP         0x7
  38 #define AD5686_CMD_DAISY_CHAIN_ENABLE           0x8
  39 #define AD5686_CMD_READBACK_ENABLE              0x9
  40
  41 #define AD5686_LDAC_PWRDN_NONE                  0x0
  42 #define AD5686_LDAC_PWRDN_1K                    0x1
  43 #define AD5686_LDAC_PWRDN_100K                  0x2
  44 #define AD5686_LDAC_PWRDN_3STATE                0x3
  45
  46 /**
  47  * struct ad5686_chip_info - chip specific information
  48  * @int_vref_mv:        AD5620/40/60: the internal reference voltage
  49  * @channel:            channel specification
  50 */
  51
  52 struct ad5686_chip_info {
  53         u16                             int_vref_mv;
  54         struct iio_chan_spec            channel[AD5686_DAC_CHANNELS];
  55 };
  56
  57 /**
  58  * struct ad5446_state - driver instance specific data
  59  * @spi:                spi_device
  60  * @chip_info:          chip model specific constants, available modes etc
  61  * @reg:                supply regulator
  62  * @vref_mv:            actual reference voltage used
  63  * @pwr_down_mask:      power down mask
  64  * @pwr_down_mode:      current power down mode
  65  * @data:               spi transfer buffers
  66  */
  67
  68 struct ad5686_state {
  69         struct spi_device               *spi;
  70         const struct ad5686_chip_info   *chip_info;
  71         struct regulator                *reg;
  72         unsigned short                  vref_mv;
  73         unsigned                        pwr_down_mask;
  74         unsigned                        pwr_down_mode;
  75         /*
  76          * DMA (thus cache coherency maintenance) requires the
  77          * transfer buffers to live in their own cache lines.
  78          */
  79
  80         union {
  81                 u32 d32;
  82                 u8 d8[4];
  83         } data[3] ____cacheline_aligned;
  84 };
  85
  86 /**
  87  * ad5686_supported_device_ids:
  88  */
  89
  90 enum ad5686_supported_device_ids {
  91         ID_AD5684,
  92         ID_AD5685,
  93         ID_AD5686,
  94 };
  95 static int ad5686_spi_write(struct ad5686_state *st,
  96                              u8 cmd, u8 addr, u16 val, u8 shift)
  97 {
  98         val <<= shift;
  99
 100         st->data[0].d32 = cpu_to_be32(AD5686_CMD(cmd) |
 101                               AD5686_ADDR(addr) |
 102                               val);
 103
 104         return spi_write(st->spi, &st->data[0].d8[1], 3);
 105 }
 106
 107 static int ad5686_spi_read(struct ad5686_state *st, u8 addr)
 108 {
 109         struct spi_transfer t[] = {
 110                 {
 111                         .tx_buf = &st->data[0].d8[1],
 112                         .len = 3,
 113                         .cs_change = 1,
 114                 }, {
 115                         .tx_buf = &st->data[1].d8[1],
 116                         .rx_buf = &st->data[2].d8[1],
 117                         .len = 3,
 118                 },
 119         };
 120         int ret;
 121
 122         st->data[0].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_READBACK_ENABLE) |
 123                               AD5686_ADDR(addr));
 124         st->data[1].d32 = cpu_to_be32(AD5686_CMD(AD5686_CMD_NOOP));
 125
 126         ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t));
 127         if (ret < 0)
 128                 return ret;
 129
 130         return be32_to_cpu(st->data[2].d32);
 131 }
 132
 133 static const char * const ad5686_powerdown_modes[] = {
 134         "1kohm_to_gnd",
 135         "100kohm_to_gnd",
 136         "three_state"
 137 };
 138
 139 static int ad5686_get_powerdown_mode(struct iio_dev *indio_dev,
 140         const struct iio_chan_spec *chan)
 141 {
 142         struct ad5686_state *st = iio_priv(indio_dev);
 143
 144         return ((st->pwr_down_mode >> (chan->channel * 2)) & 0x3) - 1;
 145 }
 146
 147 static int ad5686_set_powerdown_mode(struct iio_dev *indio_dev,
 148         const struct iio_chan_spec *chan, unsigned int mode)
 149 {
 150         struct ad5686_state *st = iio_priv(indio_dev);
 151
 152         st->pwr_down_mode &= ~(0x3 << (chan->channel * 2));
 153         st->pwr_down_mode |= ((mode + 1) << (chan->channel * 2));
 154
 155         return 0;
 156 }
 157
 158 static const struct iio_enum ad5686_powerdown_mode_enum = {
 159         .items = ad5686_powerdown_modes,
 160         .num_items = ARRAY_SIZE(ad5686_powerdown_modes),
 161         .get = ad5686_get_powerdown_mode,
 162         .set = ad5686_set_powerdown_mode,
 163 };
 164
 165 static ssize_t ad5686_read_dac_powerdown(struct iio_dev *indio_dev,
 166         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 167 {
 168         struct ad5686_state *st = iio_priv(indio_dev);
 169
 170         return sprintf(buf, "%d\n", !!(st->pwr_down_mask &
 171                         (0x3 << (chan->channel * 2))));
 172 }
 173
 174 static ssize_t ad5686_write_dac_powerdown(struct iio_dev *indio_dev,
 175          uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 176          size_t len)
 177 {
 178         bool readin;
 179         int ret;
 180         struct ad5686_state *st = iio_priv(indio_dev);
 181
 182         ret = strtobool(buf, &readin);
 183         if (ret)
 184                 return ret;
 185
 186         if (readin)
 187                 st->pwr_down_mask |= (0x3 << (chan->channel * 2));
 188         else
 189                 st->pwr_down_mask &= ~(0x3 << (chan->channel * 2));
 190
 191         ret = ad5686_spi_write(st, AD5686_CMD_POWERDOWN_DAC, 0,
 192                                st->pwr_down_mask & st->pwr_down_mode, 0);
 193
 194         return ret ? ret : len;
 195 }
 196
 197 static int ad5686_read_raw(struct iio_dev *indio_dev,
 198                            struct iio_chan_spec const *chan,
 199                            int *val,
 200                            int *val2,
 201                            long m)
 202 {
 203         struct ad5686_state *st = iio_priv(indio_dev);
 204         unsigned long scale_uv;
 205         int ret;
 206
 207         switch (m) {
 208         case IIO_CHAN_INFO_RAW:
 209                 mutex_lock(&indio_dev->mlock);
 210                 ret = ad5686_spi_read(st, chan->address);
 211                 mutex_unlock(&indio_dev->mlock);
 212                 if (ret < 0)
 213                         return ret;
 214                 *val = ret;
 215                 return IIO_VAL_INT;
 216                 break;
 217         case IIO_CHAN_INFO_SCALE:
 218                 scale_uv = (st->vref_mv * 100000)
 219                         >> (chan->scan_type.realbits);
 220                 *val =  scale_uv / 100000;
 221                 *val2 = (scale_uv % 100000) * 10;
 222                 return IIO_VAL_INT_PLUS_MICRO;
 223
 224         }
 225         return -EINVAL;
 226 }
 227
 228 static int ad5686_write_raw(struct iio_dev *indio_dev,
 229                                struct iio_chan_spec const *chan,
 230                                int val,
 231                                int val2,
 232                                long mask)
 233 {
 234         struct ad5686_state *st = iio_priv(indio_dev);
 235         int ret;
 236
 237         switch (mask) {
 238         case IIO_CHAN_INFO_RAW:
 239                 if (val > (1 << chan->scan_type.realbits) || val < 0)
 240                         return -EINVAL;
 241
 242                 mutex_lock(&indio_dev->mlock);
 243                 ret = ad5686_spi_write(st,
 244                                  AD5686_CMD_WRITE_INPUT_N_UPDATE_N,
 245                                  chan->address,
 246                                  val,
 247                                  chan->scan_type.shift);
 248                 mutex_unlock(&indio_dev->mlock);
 249                 break;
 250         default:
 251                 ret = -EINVAL;
 252         }
 253
 254         return ret;
 255 }
 256
 257 static const struct iio_info ad5686_info = {
 258         .read_raw = ad5686_read_raw,
 259         .write_raw = ad5686_write_raw,
 260         .driver_module = THIS_MODULE,
 261 };
 262
 263 static const struct iio_chan_spec_ext_info ad5686_ext_info[] = {
 264         {
 265                 .name = "powerdown",
 266                 .read = ad5686_read_dac_powerdown,
 267                 .write = ad5686_write_dac_powerdown,
 268         },
 269         IIO_ENUM("powerdown_mode", false, &ad5686_powerdown_mode_enum),
 270         IIO_ENUM_AVAILABLE("powerdown_mode", &ad5686_powerdown_mode_enum),
 271         { },
 272 };
 273
 274 #define AD5868_CHANNEL(chan, bits, shift) {                     \
 275                 .type = IIO_VOLTAGE,                            \
 276                 .indexed = 1,                                   \
 277                 .output = 1,                                    \
 278                 .channel = chan,                                \
 279                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
 280                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
 281                 .address = AD5686_ADDR_DAC(chan),               \
 282                 .scan_type = IIO_ST('u', bits, 16, shift),      \
 283                 .ext_info = ad5686_ext_info,                    \
 284 }
 285
 286 static const struct ad5686_chip_info ad5686_chip_info_tbl[] = {
 287         [ID_AD5684] = {
 288                 .channel[0] = AD5868_CHANNEL(0, 12, 4),
 289                 .channel[1] = AD5868_CHANNEL(1, 12, 4),
 290                 .channel[2] = AD5868_CHANNEL(2, 12, 4),
 291                 .channel[3] = AD5868_CHANNEL(3, 12, 4),
 292                 .int_vref_mv = 2500,
 293         },
 294         [ID_AD5685] = {
 295                 .channel[0] = AD5868_CHANNEL(0, 14, 2),
 296                 .channel[1] = AD5868_CHANNEL(1, 14, 2),
 297                 .channel[2] = AD5868_CHANNEL(2, 14, 2),
 298                 .channel[3] = AD5868_CHANNEL(3, 14, 2),
 299                 .int_vref_mv = 2500,
 300         },
 301         [ID_AD5686] = {
 302                 .channel[0] = AD5868_CHANNEL(0, 16, 0),
 303                 .channel[1] = AD5868_CHANNEL(1, 16, 0),
 304                 .channel[2] = AD5868_CHANNEL(2, 16, 0),
 305                 .channel[3] = AD5868_CHANNEL(3, 16, 0),
 306                 .int_vref_mv = 2500,
 307         },
 308 };
 309
 310
 311 static int ad5686_probe(struct spi_device *spi)
 312 {
 313         struct ad5686_state *st;
 314         struct iio_dev *indio_dev;
 315         int ret, regdone = 0, voltage_uv = 0;
 316
 317         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 318         if (indio_dev == NULL)
 319                 return  -ENOMEM;
 320
 321         st = iio_priv(indio_dev);
 322         spi_set_drvdata(spi, indio_dev);
 323
 324         st->reg = devm_regulator_get(&spi->dev, "vcc");
 325         if (!IS_ERR(st->reg)) {
 326                 ret = regulator_enable(st->reg);
 327                 if (ret)
 328                         return ret;
 329
 330                 ret = regulator_get_voltage(st->reg);
 331                 if (ret < 0)
 332                         goto error_disable_reg;
 333
 334                 voltage_uv = ret;
 335         }
 336
 337         st->chip_info =
 338                 &ad5686_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 339
 340         if (voltage_uv)
 341                 st->vref_mv = voltage_uv / 1000;
 342         else
 343                 st->vref_mv = st->chip_info->int_vref_mv;
 344
 345         st->spi = spi;
 346
 347         /* Set all the power down mode for all channels to 1K pulldown */
 348         st->pwr_down_mode = 0x55;
 349
 350         indio_dev->dev.parent = &spi->dev;
 351         indio_dev->name = spi_get_device_id(spi)->name;
 352         indio_dev->info = &ad5686_info;
 353         indio_dev->modes = INDIO_DIRECT_MODE;
 354         indio_dev->channels = st->chip_info->channel;
 355         indio_dev->num_channels = AD5686_DAC_CHANNELS;
 356
 357         regdone = 1;
 358         ret = ad5686_spi_write(st, AD5686_CMD_INTERNAL_REFER_SETUP, 0,
 359                                 !!voltage_uv, 0);
 360         if (ret)
 361                 goto error_disable_reg;
 362
 363         ret = iio_device_register(indio_dev);
 364         if (ret)
 365                 goto error_disable_reg;
 366
 367         return 0;
 368
 369 error_disable_reg:
 370         if (!IS_ERR(st->reg))
 371                 regulator_disable(st->reg);
 372         return ret;
 373 }
 374
 375 static int ad5686_remove(struct spi_device *spi)
 376 {
 377         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 378         struct ad5686_state *st = iio_priv(indio_dev);
 379
 380         iio_device_unregister(indio_dev);
 381         if (!IS_ERR(st->reg))
 382                 regulator_disable(st->reg);
 383
 384         return 0;
 385 }
 386
 387 static const struct spi_device_id ad5686_id[] = {
 388         {"ad5684", ID_AD5684},
 389         {"ad5685", ID_AD5685},
 390         {"ad5686", ID_AD5686},
 391         {}
 392 };
 393 MODULE_DEVICE_TABLE(spi, ad5686_id);
 394
 395 static struct spi_driver ad5686_driver = {
 396         .driver = {
 397                    .name = "ad5686",
 398                    .owner = THIS_MODULE,
 399                    },
 400         .probe = ad5686_probe,
 401         .remove = ad5686_remove,
 402         .id_table = ad5686_id,
 403 };
 404 module_spi_driver(ad5686_driver);
 405
 406 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 407 MODULE_DESCRIPTION("Analog Devices AD5686/85/84 DAC");
 408 MODULE_LICENSE("GPL v2");