drivers/iio/dac/ti-dac082s085.c

   1 /*
   2  * ti-dac082s085.c - Texas Instruments 8/10/12-bit 2/4-channel DAC driver
   3  *
   4  * Copyright (C) 2017 KUNBUS GmbH
   5  *
   6  * http://www.ti.com/lit/ds/symlink/dac082s085.pdf
   7  * http://www.ti.com/lit/ds/symlink/dac102s085.pdf
   8  * http://www.ti.com/lit/ds/symlink/dac122s085.pdf
   9  * http://www.ti.com/lit/ds/symlink/dac084s085.pdf
  10  * http://www.ti.com/lit/ds/symlink/dac104s085.pdf
  11  * http://www.ti.com/lit/ds/symlink/dac124s085.pdf
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License (version 2) as
  15  * published by the Free Software Foundation.
  16  */
  17
  18 #include <linux/iio/iio.h>
  19 #include <linux/module.h>
  20 #include <linux/regulator/consumer.h>
  21 #include <linux/spi/spi.h>
  22
  23 enum { dual_8bit, dual_10bit, dual_12bit, quad_8bit, quad_10bit, quad_12bit };
  24
  25 struct ti_dac_spec {
  26         u8 num_channels;
  27         u8 resolution;
  28 };
  29
  30 static const struct ti_dac_spec ti_dac_spec[] = {
  31         [dual_8bit]  = { .num_channels = 2, .resolution = 8  },
  32         [dual_10bit] = { .num_channels = 2, .resolution = 10 },
  33         [dual_12bit] = { .num_channels = 2, .resolution = 12 },
  34         [quad_8bit]  = { .num_channels = 4, .resolution = 8  },
  35         [quad_10bit] = { .num_channels = 4, .resolution = 10 },
  36         [quad_12bit] = { .num_channels = 4, .resolution = 12 },
  37 };
  38
  39 /**
  40  * struct ti_dac_chip - TI DAC chip
  41  * @lock: protects write sequences
  42  * @vref: regulator generating Vref
  43  * @mesg: SPI message to perform a write
  44  * @xfer: SPI transfer used by @mesg
  45  * @val: cached value of each output
  46  * @powerdown: whether the chip is powered down
  47  * @powerdown_mode: selected by the user
  48  * @resolution: resolution of the chip
  49  * @buf: buffer for @xfer
  50  */
  51 struct ti_dac_chip {
  52         struct mutex lock;
  53         struct regulator *vref;
  54         struct spi_message mesg;
  55         struct spi_transfer xfer;
  56         u16 val[4];
  57         bool powerdown;
  58         u8 powerdown_mode;
  59         u8 resolution;
  60         u8 buf[2] ____cacheline_aligned;
  61 };
  62
  63 #define WRITE_NOT_UPDATE(chan)  (0x00 | (chan) << 6)
  64 #define WRITE_AND_UPDATE(chan)  (0x10 | (chan) << 6)
  65 #define WRITE_ALL_UPDATE         0x20
  66 #define POWERDOWN(mode)         (0x30 | ((mode) + 1) << 6)
  67
  68 static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 cmd, u16 val)
  69 {
  70         u8 shift = 12 - ti_dac->resolution;
  71
  72         ti_dac->buf[0] = cmd | (val >> (8 - shift));
  73         ti_dac->buf[1] = (val << shift) & 0xff;
  74         return spi_sync(ti_dac->mesg.spi, &ti_dac->mesg);
  75 }
  76
  77 static const char * const ti_dac_powerdown_modes[] = {
  78         "2.5kohm_to_gnd", "100kohm_to_gnd", "three_state",
  79 };
  80
  81 static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
  82                                      const struct iio_chan_spec *chan)
  83 {
  84         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
  85
  86         return ti_dac->powerdown_mode;
  87 }
  88
  89 static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
  90                                      const struct iio_chan_spec *chan,
  91                                      unsigned int mode)
  92 {
  93         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
  94         int ret = 0;
  95
  96         if (ti_dac->powerdown_mode == mode)
  97                 return 0;
  98
  99         mutex_lock(&ti_dac->lock);
 100         if (ti_dac->powerdown) {
 101                 ret = ti_dac_cmd(ti_dac, POWERDOWN(mode), 0);
 102                 if (ret)
 103                         goto out;
 104         }
 105         ti_dac->powerdown_mode = mode;
 106
 107 out:
 108         mutex_unlock(&ti_dac->lock);
 109         return ret;
 110 }
 111
 112 static const struct iio_enum ti_dac_powerdown_mode = {
 113         .items = ti_dac_powerdown_modes,
 114         .num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
 115         .get = ti_dac_get_powerdown_mode,
 116         .set = ti_dac_set_powerdown_mode,
 117 };
 118
 119 static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
 120                                      uintptr_t private,
 121                                      const struct iio_chan_spec *chan,
 122                                      char *buf)
 123 {
 124         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 125
 126         return sprintf(buf, "%d\n", ti_dac->powerdown);
 127 }
 128
 129 static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
 130                                       uintptr_t private,
 131                                       const struct iio_chan_spec *chan,
 132                                       const char *buf, size_t len)
 133 {
 134         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 135         bool powerdown;
 136         int ret;
 137
 138         ret = strtobool(buf, &powerdown);
 139         if (ret)
 140                 return ret;
 141
 142         if (ti_dac->powerdown == powerdown)
 143                 return len;
 144
 145         mutex_lock(&ti_dac->lock);
 146         if (powerdown)
 147                 ret = ti_dac_cmd(ti_dac, POWERDOWN(ti_dac->powerdown_mode), 0);
 148         else
 149                 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(0), ti_dac->val[0]);
 150         if (!ret)
 151                 ti_dac->powerdown = powerdown;
 152         mutex_unlock(&ti_dac->lock);
 153
 154         return ret ? ret : len;
 155 }
 156
 157 static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
 158         {
 159                 .name      = "powerdown",
 160                 .read      = ti_dac_read_powerdown,
 161                 .write     = ti_dac_write_powerdown,
 162                 .shared    = IIO_SHARED_BY_TYPE,
 163         },
 164         IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
 165         IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode),
 166         { },
 167 };
 168
 169 #define TI_DAC_CHANNEL(chan) {                                  \
 170         .type = IIO_VOLTAGE,                                    \
 171         .channel = (chan),                                      \
 172         .address = (chan),                                      \
 173         .indexed = true,                                        \
 174         .output = true,                                         \
 175         .datasheet_name = (const char[]){ 'A' + (chan), 0 },    \
 176         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 177         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 178         .ext_info = ti_dac_ext_info,                            \
 179 }
 180
 181 static const struct iio_chan_spec ti_dac_channels[] = {
 182         TI_DAC_CHANNEL(0),
 183         TI_DAC_CHANNEL(1),
 184         TI_DAC_CHANNEL(2),
 185         TI_DAC_CHANNEL(3),
 186 };
 187
 188 static int ti_dac_read_raw(struct iio_dev *indio_dev,
 189                            struct iio_chan_spec const *chan,
 190                            int *val, int *val2, long mask)
 191 {
 192         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 193         int ret;
 194
 195         switch (mask) {
 196         case IIO_CHAN_INFO_RAW:
 197                 *val = ti_dac->val[chan->channel];
 198                 ret = IIO_VAL_INT;
 199                 break;
 200
 201         case IIO_CHAN_INFO_SCALE:
 202                 ret = regulator_get_voltage(ti_dac->vref);
 203                 if (ret < 0)
 204                         return ret;
 205
 206                 *val = ret / 1000;
 207                 *val2 = ti_dac->resolution;
 208                 ret = IIO_VAL_FRACTIONAL_LOG2;
 209                 break;
 210
 211         default:
 212                 ret = -EINVAL;
 213         }
 214
 215         return ret;
 216 }
 217
 218 static int ti_dac_write_raw(struct iio_dev *indio_dev,
 219                             struct iio_chan_spec const *chan,
 220                             int val, int val2, long mask)
 221 {
 222         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 223         int ret;
 224
 225         switch (mask) {
 226         case IIO_CHAN_INFO_RAW:
 227                 if (ti_dac->val[chan->channel] == val)
 228                         return 0;
 229
 230                 if (val >= (1 << ti_dac->resolution) || val < 0)
 231                         return -EINVAL;
 232
 233                 if (ti_dac->powerdown)
 234                         return -EBUSY;
 235
 236                 mutex_lock(&ti_dac->lock);
 237                 ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(chan->channel), val);
 238                 if (!ret)
 239                         ti_dac->val[chan->channel] = val;
 240                 mutex_unlock(&ti_dac->lock);
 241                 break;
 242
 243         default:
 244                 ret = -EINVAL;
 245         }
 246
 247         return ret;
 248 }
 249
 250 static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
 251                                     struct iio_chan_spec const *chan, long mask)
 252 {
 253         return IIO_VAL_INT;
 254 }
 255
 256 static const struct iio_info ti_dac_info = {
 257         .read_raw          = ti_dac_read_raw,
 258         .write_raw         = ti_dac_write_raw,
 259         .write_raw_get_fmt = ti_dac_write_raw_get_fmt,
 260 };
 261
 262 static int ti_dac_probe(struct spi_device *spi)
 263 {
 264         struct device *dev = &spi->dev;
 265         const struct ti_dac_spec *spec;
 266         struct ti_dac_chip *ti_dac;
 267         struct iio_dev *indio_dev;
 268         int ret;
 269
 270         indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
 271         if (!indio_dev)
 272                 return -ENOMEM;
 273
 274         indio_dev->dev.parent = dev;
 275         indio_dev->info = &ti_dac_info;
 276         indio_dev->name = spi->modalias;
 277         indio_dev->modes = INDIO_DIRECT_MODE;
 278         indio_dev->channels = ti_dac_channels;
 279         spi_set_drvdata(spi, indio_dev);
 280
 281         ti_dac = iio_priv(indio_dev);
 282         ti_dac->xfer.tx_buf = &ti_dac->buf;
 283         ti_dac->xfer.len = sizeof(ti_dac->buf);
 284         spi_message_init_with_transfers(&ti_dac->mesg, &ti_dac->xfer, 1);
 285         ti_dac->mesg.spi = spi;
 286
 287         spec = &ti_dac_spec[spi_get_device_id(spi)->driver_data];
 288         indio_dev->num_channels = spec->num_channels;
 289         ti_dac->resolution = spec->resolution;
 290
 291         ti_dac->vref = devm_regulator_get(dev, "vref");
 292         if (IS_ERR(ti_dac->vref))
 293                 return PTR_ERR(ti_dac->vref);
 294
 295         ret = regulator_enable(ti_dac->vref);
 296         if (ret < 0)
 297                 return ret;
 298
 299         mutex_init(&ti_dac->lock);
 300
 301         ret = ti_dac_cmd(ti_dac, WRITE_ALL_UPDATE, 0);
 302         if (ret) {
 303                 dev_err(dev, "failed to initialize outputs to 0\n");
 304                 goto err;
 305         }
 306
 307         ret = iio_device_register(indio_dev);
 308         if (ret)
 309                 goto err;
 310
 311         return 0;
 312
 313 err:
 314         mutex_destroy(&ti_dac->lock);
 315         regulator_disable(ti_dac->vref);
 316         return ret;
 317 }
 318
 319 static int ti_dac_remove(struct spi_device *spi)
 320 {
 321         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 322         struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
 323
 324         iio_device_unregister(indio_dev);
 325         mutex_destroy(&ti_dac->lock);
 326         regulator_disable(ti_dac->vref);
 327
 328         return 0;
 329 }
 330
 331 #ifdef CONFIG_OF
 332 static const struct of_device_id ti_dac_of_id[] = {
 333         { .compatible = "ti,dac082s085" },
 334         { .compatible = "ti,dac102s085" },
 335         { .compatible = "ti,dac122s085" },
 336         { .compatible = "ti,dac084s085" },
 337         { .compatible = "ti,dac104s085" },
 338         { .compatible = "ti,dac124s085" },
 339         { }
 340 };
 341 MODULE_DEVICE_TABLE(of, ti_dac_of_id);
 342 #endif
 343
 344 static const struct spi_device_id ti_dac_spi_id[] = {
 345         { "dac082s085", dual_8bit  },
 346         { "dac102s085", dual_10bit },
 347         { "dac122s085", dual_12bit },
 348         { "dac084s085", quad_8bit  },
 349         { "dac104s085", quad_10bit },
 350         { "dac124s085", quad_12bit },
 351         { }
 352 };
 353 MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
 354
 355 static struct spi_driver ti_dac_driver = {
 356         .driver = {
 357                 .name           = "ti-dac082s085",
 358                 .of_match_table = of_match_ptr(ti_dac_of_id),
 359         },
 360         .probe    = ti_dac_probe,
 361         .remove   = ti_dac_remove,
 362         .id_table = ti_dac_spi_id,
 363 };
 364 module_spi_driver(ti_dac_driver);
 365
 366 MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
 367 MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 2/4-channel DAC driver");
 368 MODULE_LICENSE("GPL v2");