drivers/iio/dac/max5821.c

   1  /*
   2   * iio/dac/max5821.c
   3   * Copyright (C) 2014 Philippe Reynes
   4   *
   5   * This program is free software; you can redistribute it and/or modify
   6   * it under the terms of the GNU General Public License version 2 as
   7   * published by the Free Software Foundation.
   8   */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/i2c.h>
  13 #include <linux/iio/iio.h>
  14 #include <linux/regulator/consumer.h>
  15
  16 #define MAX5821_MAX_DAC_CHANNELS                2
  17
  18 /* command bytes */
  19 #define MAX5821_LOAD_DAC_A_IN_REG_B             0x00
  20 #define MAX5821_LOAD_DAC_B_IN_REG_A             0x10
  21 #define MAX5821_EXTENDED_COMMAND_MODE           0xf0
  22 #define MAX5821_READ_DAC_A_COMMAND              0xf1
  23 #define MAX5821_READ_DAC_B_COMMAND              0xf2
  24
  25 #define MAX5821_EXTENDED_POWER_UP               0x00
  26 #define MAX5821_EXTENDED_POWER_DOWN_MODE0       0x01
  27 #define MAX5821_EXTENDED_POWER_DOWN_MODE1       0x02
  28 #define MAX5821_EXTENDED_POWER_DOWN_MODE2       0x03
  29 #define MAX5821_EXTENDED_DAC_A                  0x04
  30 #define MAX5821_EXTENDED_DAC_B                  0x08
  31
  32 enum max5821_device_ids {
  33         ID_MAX5821,
  34 };
  35
  36 struct max5821_data {
  37         struct i2c_client       *client;
  38         struct regulator        *vref_reg;
  39         unsigned short          vref_mv;
  40         bool                    powerdown[MAX5821_MAX_DAC_CHANNELS];
  41         u8                      powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
  42         struct mutex            lock;
  43 };
  44
  45 static const char * const max5821_powerdown_modes[] = {
  46         "three_state",
  47         "1kohm_to_gnd",
  48         "100kohm_to_gnd",
  49 };
  50
  51 enum {
  52         MAX5821_THREE_STATE,
  53         MAX5821_1KOHM_TO_GND,
  54         MAX5821_100KOHM_TO_GND
  55 };
  56
  57 static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
  58                                       const struct iio_chan_spec *chan)
  59 {
  60         struct max5821_data *st = iio_priv(indio_dev);
  61
  62         return st->powerdown_mode[chan->channel];
  63 }
  64
  65 static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
  66                                       const struct iio_chan_spec *chan,
  67                                       unsigned int mode)
  68 {
  69         struct max5821_data *st = iio_priv(indio_dev);
  70
  71         st->powerdown_mode[chan->channel] = mode;
  72
  73         return 0;
  74 }
  75
  76 static const struct iio_enum max5821_powerdown_mode_enum = {
  77         .items = max5821_powerdown_modes,
  78         .num_items = ARRAY_SIZE(max5821_powerdown_modes),
  79         .get = max5821_get_powerdown_mode,
  80         .set = max5821_set_powerdown_mode,
  81 };
  82
  83 static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
  84                                           uintptr_t private,
  85                                           const struct iio_chan_spec *chan,
  86                                           char *buf)
  87 {
  88         struct max5821_data *st = iio_priv(indio_dev);
  89
  90         return sprintf(buf, "%d\n", st->powerdown[chan->channel]);
  91 }
  92
  93 static int max5821_sync_powerdown_mode(struct max5821_data *data,
  94                                        const struct iio_chan_spec *chan)
  95 {
  96         u8 outbuf[2];
  97
  98         outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
  99
 100         if (chan->channel == 0)
 101                 outbuf[1] = MAX5821_EXTENDED_DAC_A;
 102         else
 103                 outbuf[1] = MAX5821_EXTENDED_DAC_B;
 104
 105         if (data->powerdown[chan->channel])
 106                 outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
 107         else
 108                 outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
 109
 110         return i2c_master_send(data->client, outbuf, 2);
 111 }
 112
 113 static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
 114                                            uintptr_t private,
 115                                            const struct iio_chan_spec *chan,
 116                                            const char *buf, size_t len)
 117 {
 118         struct max5821_data *data = iio_priv(indio_dev);
 119         bool powerdown;
 120         int ret;
 121
 122         ret = strtobool(buf, &powerdown);
 123         if (ret)
 124                 return ret;
 125
 126         data->powerdown[chan->channel] = powerdown;
 127
 128         ret = max5821_sync_powerdown_mode(data, chan);
 129         if (ret < 0)
 130                 return ret;
 131
 132         return len;
 133 }
 134
 135 static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
 136         {
 137                 .name = "powerdown",
 138                 .read = max5821_read_dac_powerdown,
 139                 .write = max5821_write_dac_powerdown,
 140                 .shared = IIO_SEPARATE,
 141         },
 142         IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
 143         IIO_ENUM_AVAILABLE("powerdown_mode", &max5821_powerdown_mode_enum),
 144         { },
 145 };
 146
 147 #define MAX5821_CHANNEL(chan) {                                 \
 148         .type = IIO_VOLTAGE,                                    \
 149         .indexed = 1,                                           \
 150         .output = 1,                                            \
 151         .channel = (chan),                                      \
 152         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 153         .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),    \
 154         .ext_info = max5821_ext_info,                           \
 155 }
 156
 157 static const struct iio_chan_spec max5821_channels[] = {
 158         MAX5821_CHANNEL(0),
 159         MAX5821_CHANNEL(1)
 160 };
 161
 162 static const u8 max5821_read_dac_command[] = {
 163         MAX5821_READ_DAC_A_COMMAND,
 164         MAX5821_READ_DAC_B_COMMAND
 165 };
 166
 167 static const u8 max5821_load_dac_command[] = {
 168         MAX5821_LOAD_DAC_A_IN_REG_B,
 169         MAX5821_LOAD_DAC_B_IN_REG_A
 170 };
 171
 172 static int max5821_get_value(struct iio_dev *indio_dev,
 173                              int *val, int channel)
 174 {
 175         struct max5821_data *data = iio_priv(indio_dev);
 176         struct i2c_client *client = data->client;
 177         u8 outbuf[1];
 178         u8 inbuf[2];
 179         int ret;
 180
 181         if ((channel != 0) && (channel != 1))
 182                 return -EINVAL;
 183
 184         outbuf[0] = max5821_read_dac_command[channel];
 185
 186         mutex_lock(&data->lock);
 187
 188         ret = i2c_master_send(client, outbuf, 1);
 189         if (ret < 0) {
 190                 mutex_unlock(&data->lock);
 191                 return ret;
 192         } else if (ret != 1) {
 193                 mutex_unlock(&data->lock);
 194                 return -EIO;
 195         }
 196
 197         ret = i2c_master_recv(client, inbuf, 2);
 198         if (ret < 0) {
 199                 mutex_unlock(&data->lock);
 200                 return ret;
 201         } else if (ret != 2) {
 202                 mutex_unlock(&data->lock);
 203                 return -EIO;
 204         }
 205
 206         mutex_unlock(&data->lock);
 207
 208         *val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
 209
 210         return IIO_VAL_INT;
 211 }
 212
 213 static int max5821_set_value(struct iio_dev *indio_dev,
 214                              int val, int channel)
 215 {
 216         struct max5821_data *data = iio_priv(indio_dev);
 217         struct i2c_client *client = data->client;
 218         u8 outbuf[2];
 219         int ret;
 220
 221         if ((val < 0) || (val > 1023))
 222                 return -EINVAL;
 223
 224         if ((channel != 0) && (channel != 1))
 225                 return -EINVAL;
 226
 227         outbuf[0] = max5821_load_dac_command[channel];
 228         outbuf[0] |= val >> 6;
 229         outbuf[1] = (val & 0x3f) << 2;
 230
 231         ret = i2c_master_send(client, outbuf, 2);
 232         if (ret < 0)
 233                 return ret;
 234         else if (ret != 2)
 235                 return -EIO;
 236         else
 237                 return 0;
 238 }
 239
 240 static int max5821_read_raw(struct iio_dev *indio_dev,
 241                            struct iio_chan_spec const *chan,
 242                            int *val, int *val2, long mask)
 243 {
 244         struct max5821_data *data = iio_priv(indio_dev);
 245
 246         switch (mask) {
 247         case IIO_CHAN_INFO_RAW:
 248                 return max5821_get_value(indio_dev, val, chan->channel);
 249         case IIO_CHAN_INFO_SCALE:
 250                 *val = data->vref_mv;
 251                 *val2 = 10;
 252                 return IIO_VAL_FRACTIONAL_LOG2;
 253         default:
 254                 return -EINVAL;
 255         }
 256 }
 257
 258 static int max5821_write_raw(struct iio_dev *indio_dev,
 259                              struct iio_chan_spec const *chan,
 260                              int val, int val2, long mask)
 261 {
 262         if (val2 != 0)
 263                 return -EINVAL;
 264
 265         switch (mask) {
 266         case IIO_CHAN_INFO_RAW:
 267                 return max5821_set_value(indio_dev, val, chan->channel);
 268         default:
 269                 return -EINVAL;
 270         }
 271 }
 272
 273 #ifdef CONFIG_PM_SLEEP
 274 static int max5821_suspend(struct device *dev)
 275 {
 276         u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
 277                          MAX5821_EXTENDED_DAC_A |
 278                          MAX5821_EXTENDED_DAC_B |
 279                          MAX5821_EXTENDED_POWER_DOWN_MODE2 };
 280
 281         return i2c_master_send(to_i2c_client(dev), outbuf, 2);
 282 }
 283
 284 static int max5821_resume(struct device *dev)
 285 {
 286         u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
 287                          MAX5821_EXTENDED_DAC_A |
 288                          MAX5821_EXTENDED_DAC_B |
 289                          MAX5821_EXTENDED_POWER_UP };
 290
 291         return i2c_master_send(to_i2c_client(dev), outbuf, 2);
 292 }
 293
 294 static SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend, max5821_resume);
 295 #define MAX5821_PM_OPS (&max5821_pm_ops)
 296 #else
 297 #define MAX5821_PM_OPS NULL
 298 #endif /* CONFIG_PM_SLEEP */
 299
 300 static const struct iio_info max5821_info = {
 301         .read_raw = max5821_read_raw,
 302         .write_raw = max5821_write_raw,
 303 };
 304
 305 static int max5821_probe(struct i2c_client *client,
 306                         const struct i2c_device_id *id)
 307 {
 308         struct max5821_data *data;
 309         struct iio_dev *indio_dev;
 310         u32 tmp;
 311         int ret;
 312
 313         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 314         if (!indio_dev)
 315                 return -ENOMEM;
 316         data = iio_priv(indio_dev);
 317         i2c_set_clientdata(client, indio_dev);
 318         data->client = client;
 319         mutex_init(&data->lock);
 320
 321         /* max5821 start in powerdown mode 100Kohm to ground */
 322         for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
 323                 data->powerdown[tmp] = true;
 324                 data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
 325         }
 326
 327         data->vref_reg = devm_regulator_get(&client->dev, "vref");
 328         if (IS_ERR(data->vref_reg)) {
 329                 ret = PTR_ERR(data->vref_reg);
 330                 dev_err(&client->dev,
 331                         "Failed to get vref regulator: %d\n", ret);
 332                 goto error_free_reg;
 333         }
 334
 335         ret = regulator_enable(data->vref_reg);
 336         if (ret) {
 337                 dev_err(&client->dev,
 338                         "Failed to enable vref regulator: %d\n", ret);
 339                 goto error_free_reg;
 340         }
 341
 342         ret = regulator_get_voltage(data->vref_reg);
 343         if (ret < 0) {
 344                 dev_err(&client->dev,
 345                         "Failed to get voltage on regulator: %d\n", ret);
 346                 goto error_disable_reg;
 347         }
 348
 349         data->vref_mv = ret / 1000;
 350
 351         indio_dev->name = id->name;
 352         indio_dev->dev.parent = &client->dev;
 353         indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
 354         indio_dev->channels = max5821_channels;
 355         indio_dev->modes = INDIO_DIRECT_MODE;
 356         indio_dev->info = &max5821_info;
 357
 358         return iio_device_register(indio_dev);
 359
 360 error_disable_reg:
 361         regulator_disable(data->vref_reg);
 362
 363 error_free_reg:
 364
 365         return ret;
 366 }
 367
 368 static int max5821_remove(struct i2c_client *client)
 369 {
 370         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 371         struct max5821_data *data = iio_priv(indio_dev);
 372
 373         iio_device_unregister(indio_dev);
 374         regulator_disable(data->vref_reg);
 375
 376         return 0;
 377 }
 378
 379 static const struct i2c_device_id max5821_id[] = {
 380         { "max5821", ID_MAX5821 },
 381         { }
 382 };
 383 MODULE_DEVICE_TABLE(i2c, max5821_id);
 384
 385 static const struct of_device_id max5821_of_match[] = {
 386         { .compatible = "maxim,max5821" },
 387         { }
 388 };
 389 MODULE_DEVICE_TABLE(of, max5821_of_match);
 390
 391 static struct i2c_driver max5821_driver = {
 392         .driver = {
 393                 .name   = "max5821",
 394                 .of_match_table = max5821_of_match,
 395                 .pm     = MAX5821_PM_OPS,
 396         },
 397         .probe          = max5821_probe,
 398         .remove         = max5821_remove,
 399         .id_table       = max5821_id,
 400 };
 401 module_i2c_driver(max5821_driver);
 402
 403 MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
 404 MODULE_DESCRIPTION("MAX5821 DAC");
 405 MODULE_LICENSE("GPL v2");