drivers/iio/dac/ad5504.c

   1 /*
   2  * AD5504, AD5501 High Voltage Digital to Analog Converter
   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/kernel.h>
  13 #include <linux/spi/spi.h>
  14 #include <linux/slab.h>
  15 #include <linux/sysfs.h>
  16 #include <linux/regulator/consumer.h>
  17 #include <linux/module.h>
  18
  19 #include <linux/iio/iio.h>
  20 #include <linux/iio/sysfs.h>
  21 #include <linux/iio/events.h>
  22 #include <linux/iio/dac/ad5504.h>
  23
  24 #define AD5505_BITS                     12
  25 #define AD5504_RES_MASK                 ((1 << (AD5505_BITS)) - 1)
  26
  27 #define AD5504_CMD_READ                 (1 << 15)
  28 #define AD5504_CMD_WRITE                (0 << 15)
  29 #define AD5504_ADDR(addr)               ((addr) << 12)
  30
  31 /* Registers */
  32 #define AD5504_ADDR_NOOP                0
  33 #define AD5504_ADDR_DAC(x)              ((x) + 1)
  34 #define AD5504_ADDR_ALL_DAC             5
  35 #define AD5504_ADDR_CTRL                7
  36
  37 /* Control Register */
  38 #define AD5504_DAC_PWR(ch)              ((ch) << 2)
  39 #define AD5504_DAC_PWRDWN_MODE(mode)    ((mode) << 6)
  40 #define AD5504_DAC_PWRDN_20K            0
  41 #define AD5504_DAC_PWRDN_3STATE         1
  42
  43 /**
  44  * struct ad5446_state - driver instance specific data
  45  * @us:                 spi_device
  46  * @reg:                supply regulator
  47  * @vref_mv:            actual reference voltage used
  48  * @pwr_down_mask       power down mask
  49  * @pwr_down_mode       current power down mode
  50  * @data:               transfer buffer
  51  */
  52 struct ad5504_state {
  53         struct spi_device               *spi;
  54         struct regulator                *reg;
  55         unsigned short                  vref_mv;
  56         unsigned                        pwr_down_mask;
  57         unsigned                        pwr_down_mode;
  58
  59         __be16                          data[2] ____cacheline_aligned;
  60 };
  61
  62 /**
  63  * ad5504_supported_device_ids:
  64  */
  65
  66 enum ad5504_supported_device_ids {
  67         ID_AD5504,
  68         ID_AD5501,
  69 };
  70
  71 static int ad5504_spi_write(struct ad5504_state *st, u8 addr, u16 val)
  72 {
  73         st->data[0] = cpu_to_be16(AD5504_CMD_WRITE | AD5504_ADDR(addr) |
  74                               (val & AD5504_RES_MASK));
  75
  76         return spi_write(st->spi, &st->data[0], 2);
  77 }
  78
  79 static int ad5504_spi_read(struct ad5504_state *st, u8 addr)
  80 {
  81         int ret;
  82         struct spi_transfer t = {
  83             .tx_buf = &st->data[0],
  84             .rx_buf = &st->data[1],
  85             .len = 2,
  86         };
  87
  88         st->data[0] = cpu_to_be16(AD5504_CMD_READ | AD5504_ADDR(addr));
  89         ret = spi_sync_transfer(st->spi, &t, 1);
  90         if (ret < 0)
  91                 return ret;
  92
  93         return be16_to_cpu(st->data[1]) & AD5504_RES_MASK;
  94 }
  95
  96 static int ad5504_read_raw(struct iio_dev *indio_dev,
  97                            struct iio_chan_spec const *chan,
  98                            int *val,
  99                            int *val2,
 100                            long m)
 101 {
 102         struct ad5504_state *st = iio_priv(indio_dev);
 103         int ret;
 104
 105         switch (m) {
 106         case IIO_CHAN_INFO_RAW:
 107                 ret = ad5504_spi_read(st, chan->address);
 108                 if (ret < 0)
 109                         return ret;
 110
 111                 *val = ret;
 112
 113                 return IIO_VAL_INT;
 114         case IIO_CHAN_INFO_SCALE:
 115                 *val = st->vref_mv;
 116                 *val2 = chan->scan_type.realbits;
 117                 return IIO_VAL_FRACTIONAL_LOG2;
 118         }
 119         return -EINVAL;
 120 }
 121
 122 static int ad5504_write_raw(struct iio_dev *indio_dev,
 123                                struct iio_chan_spec const *chan,
 124                                int val,
 125                                int val2,
 126                                long mask)
 127 {
 128         struct ad5504_state *st = iio_priv(indio_dev);
 129         int ret;
 130
 131         switch (mask) {
 132         case IIO_CHAN_INFO_RAW:
 133                 if (val >= (1 << chan->scan_type.realbits) || val < 0)
 134                         return -EINVAL;
 135
 136                 return ad5504_spi_write(st, chan->address, val);
 137         default:
 138                 ret = -EINVAL;
 139         }
 140
 141         return -EINVAL;
 142 }
 143
 144 static const char * const ad5504_powerdown_modes[] = {
 145         "20kohm_to_gnd",
 146         "three_state",
 147 };
 148
 149 static int ad5504_get_powerdown_mode(struct iio_dev *indio_dev,
 150         const struct iio_chan_spec *chan)
 151 {
 152         struct ad5504_state *st = iio_priv(indio_dev);
 153
 154         return st->pwr_down_mode;
 155 }
 156
 157 static int ad5504_set_powerdown_mode(struct iio_dev *indio_dev,
 158         const struct iio_chan_spec *chan, unsigned int mode)
 159 {
 160         struct ad5504_state *st = iio_priv(indio_dev);
 161
 162         st->pwr_down_mode = mode;
 163
 164         return 0;
 165 }
 166
 167 static const struct iio_enum ad5504_powerdown_mode_enum = {
 168         .items = ad5504_powerdown_modes,
 169         .num_items = ARRAY_SIZE(ad5504_powerdown_modes),
 170         .get = ad5504_get_powerdown_mode,
 171         .set = ad5504_set_powerdown_mode,
 172 };
 173
 174 static ssize_t ad5504_read_dac_powerdown(struct iio_dev *indio_dev,
 175         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 176 {
 177         struct ad5504_state *st = iio_priv(indio_dev);
 178
 179         return sprintf(buf, "%d\n",
 180                         !(st->pwr_down_mask & (1 << chan->channel)));
 181 }
 182
 183 static ssize_t ad5504_write_dac_powerdown(struct iio_dev *indio_dev,
 184         uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
 185         size_t len)
 186 {
 187         bool pwr_down;
 188         int ret;
 189         struct ad5504_state *st = iio_priv(indio_dev);
 190
 191         ret = strtobool(buf, &pwr_down);
 192         if (ret)
 193                 return ret;
 194
 195         if (pwr_down)
 196                 st->pwr_down_mask |= (1 << chan->channel);
 197         else
 198                 st->pwr_down_mask &= ~(1 << chan->channel);
 199
 200         ret = ad5504_spi_write(st, AD5504_ADDR_CTRL,
 201                                 AD5504_DAC_PWRDWN_MODE(st->pwr_down_mode) |
 202                                 AD5504_DAC_PWR(st->pwr_down_mask));
 203
 204         /* writes to the CTRL register must be followed by a NOOP */
 205         ad5504_spi_write(st, AD5504_ADDR_NOOP, 0);
 206
 207         return ret ? ret : len;
 208 }
 209
 210 static IIO_CONST_ATTR(temp0_thresh_rising_value, "110000");
 211 static IIO_CONST_ATTR(temp0_thresh_rising_en, "1");
 212
 213 static struct attribute *ad5504_ev_attributes[] = {
 214         &iio_const_attr_temp0_thresh_rising_value.dev_attr.attr,
 215         &iio_const_attr_temp0_thresh_rising_en.dev_attr.attr,
 216         NULL,
 217 };
 218
 219 static struct attribute_group ad5504_ev_attribute_group = {
 220         .attrs = ad5504_ev_attributes,
 221         .name = "events",
 222 };
 223
 224 static irqreturn_t ad5504_event_handler(int irq, void *private)
 225 {
 226         iio_push_event(private,
 227                        IIO_UNMOD_EVENT_CODE(IIO_TEMP,
 228                                             0,
 229                                             IIO_EV_TYPE_THRESH,
 230                                             IIO_EV_DIR_RISING),
 231                        iio_get_time_ns());
 232
 233         return IRQ_HANDLED;
 234 }
 235
 236 static const struct iio_info ad5504_info = {
 237         .write_raw = ad5504_write_raw,
 238         .read_raw = ad5504_read_raw,
 239         .event_attrs = &ad5504_ev_attribute_group,
 240         .driver_module = THIS_MODULE,
 241 };
 242
 243 static const struct iio_chan_spec_ext_info ad5504_ext_info[] = {
 244         {
 245                 .name = "powerdown",
 246                 .read = ad5504_read_dac_powerdown,
 247                 .write = ad5504_write_dac_powerdown,
 248                 .shared = IIO_SEPARATE,
 249         },
 250         IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE,
 251                  &ad5504_powerdown_mode_enum),
 252         IIO_ENUM_AVAILABLE("powerdown_mode", &ad5504_powerdown_mode_enum),
 253         { },
 254 };
 255
 256 #define AD5504_CHANNEL(_chan) { \
 257         .type = IIO_VOLTAGE, \
 258         .indexed = 1, \
 259         .output = 1, \
 260         .channel = (_chan), \
 261         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 262         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
 263         .address = AD5504_ADDR_DAC(_chan), \
 264         .scan_type = { \
 265                 .sign = 'u', \
 266                 .realbits = 12, \
 267                 .storagebits = 16, \
 268         }, \
 269         .ext_info = ad5504_ext_info, \
 270 }
 271
 272 static const struct iio_chan_spec ad5504_channels[] = {
 273         AD5504_CHANNEL(0),
 274         AD5504_CHANNEL(1),
 275         AD5504_CHANNEL(2),
 276         AD5504_CHANNEL(3),
 277 };
 278
 279 static int ad5504_probe(struct spi_device *spi)
 280 {
 281         struct ad5504_platform_data *pdata = spi->dev.platform_data;
 282         struct iio_dev *indio_dev;
 283         struct ad5504_state *st;
 284         struct regulator *reg;
 285         int ret, voltage_uv = 0;
 286
 287         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 288         if (!indio_dev)
 289                 return -ENOMEM;
 290         reg = devm_regulator_get(&spi->dev, "vcc");
 291         if (!IS_ERR(reg)) {
 292                 ret = regulator_enable(reg);
 293                 if (ret)
 294                         return ret;
 295
 296                 ret = regulator_get_voltage(reg);
 297                 if (ret < 0)
 298                         goto error_disable_reg;
 299
 300                 voltage_uv = ret;
 301         }
 302
 303         spi_set_drvdata(spi, indio_dev);
 304         st = iio_priv(indio_dev);
 305         if (voltage_uv)
 306                 st->vref_mv = voltage_uv / 1000;
 307         else if (pdata)
 308                 st->vref_mv = pdata->vref_mv;
 309         else
 310                 dev_warn(&spi->dev, "reference voltage unspecified\n");
 311
 312         st->reg = reg;
 313         st->spi = spi;
 314         indio_dev->dev.parent = &spi->dev;
 315         indio_dev->name = spi_get_device_id(st->spi)->name;
 316         indio_dev->info = &ad5504_info;
 317         if (spi_get_device_id(st->spi)->driver_data == ID_AD5501)
 318                 indio_dev->num_channels = 1;
 319         else
 320                 indio_dev->num_channels = 4;
 321         indio_dev->channels = ad5504_channels;
 322         indio_dev->modes = INDIO_DIRECT_MODE;
 323
 324         if (spi->irq) {
 325                 ret = devm_request_threaded_irq(&spi->dev, spi->irq,
 326                                            NULL,
 327                                            &ad5504_event_handler,
 328                                            IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 329                                            spi_get_device_id(st->spi)->name,
 330                                            indio_dev);
 331                 if (ret)
 332                         goto error_disable_reg;
 333         }
 334
 335         ret = iio_device_register(indio_dev);
 336         if (ret)
 337                 goto error_disable_reg;
 338
 339         return 0;
 340
 341 error_disable_reg:
 342         if (!IS_ERR(reg))
 343                 regulator_disable(reg);
 344
 345         return ret;
 346 }
 347
 348 static int ad5504_remove(struct spi_device *spi)
 349 {
 350         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 351         struct ad5504_state *st = iio_priv(indio_dev);
 352
 353         iio_device_unregister(indio_dev);
 354
 355         if (!IS_ERR(st->reg))
 356                 regulator_disable(st->reg);
 357
 358         return 0;
 359 }
 360
 361 static const struct spi_device_id ad5504_id[] = {
 362         {"ad5504", ID_AD5504},
 363         {"ad5501", ID_AD5501},
 364         {}
 365 };
 366 MODULE_DEVICE_TABLE(spi, ad5504_id);
 367
 368 static struct spi_driver ad5504_driver = {
 369         .driver = {
 370                    .name = "ad5504",
 371                    .owner = THIS_MODULE,
 372                    },
 373         .probe = ad5504_probe,
 374         .remove = ad5504_remove,
 375         .id_table = ad5504_id,
 376 };
 377 module_spi_driver(ad5504_driver);
 378
 379 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 380 MODULE_DESCRIPTION("Analog Devices AD5501/AD5501 DAC");
 381 MODULE_LICENSE("GPL v2");