drivers/iio/dac/max5821.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2  /*
   3   * iio/dac/max5821.c
   4   * Copyright (C) 2014 Philippe Reynes
   5   */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/i2c.h>
  10 #include <linux/iio/iio.h>
  11 #include <linux/regulator/consumer.h>
  12
  13 #define MAX5821_MAX_DAC_CHANNELS                2
  14
  15 /* command bytes */
  16 #define MAX5821_LOAD_DAC_A_IN_REG_B             0x00
  17 #define MAX5821_LOAD_DAC_B_IN_REG_A             0x10
  18 #define MAX5821_EXTENDED_COMMAND_MODE           0xf0
  19 #define MAX5821_READ_DAC_A_COMMAND              0xf1
  20 #define MAX5821_READ_DAC_B_COMMAND              0xf2
  21
  22 #define MAX5821_EXTENDED_POWER_UP               0x00
  23 #define MAX5821_EXTENDED_POWER_DOWN_MODE0       0x01
  24 #define MAX5821_EXTENDED_POWER_DOWN_MODE1       0x02
  25 #define MAX5821_EXTENDED_POWER_DOWN_MODE2       0x03
  26 #define MAX5821_EXTENDED_DAC_A                  0x04
  27 #define MAX5821_EXTENDED_DAC_B                  0x08
  28
  29 enum max5821_device_ids {
  30         ID_MAX5821,
  31 };
  32
  33 struct max5821_data {
  34         struct i2c_client       *client;
  35         struct regulator        *vref_reg;
  36         unsigned short          vref_mv;
  37         bool                    powerdown[MAX5821_MAX_DAC_CHANNELS];
  38         u8                      powerdown_mode[MAX5821_MAX_DAC_CHANNELS];
  39         struct mutex            lock;
  40 };
  41
  42 static const char * const max5821_powerdown_modes[] = {
  43         "three_state",
  44         "1kohm_to_gnd",
  45         "100kohm_to_gnd",
  46 };
  47
  48 enum {
  49         MAX5821_THREE_STATE,
  50         MAX5821_1KOHM_TO_GND,
  51         MAX5821_100KOHM_TO_GND
  52 };
  53
  54 static int max5821_get_powerdown_mode(struct iio_dev *indio_dev,
  55                                       const struct iio_chan_spec *chan)
  56 {
  57         struct max5821_data *st = iio_priv(indio_dev);
  58
  59         return st->powerdown_mode[chan->channel];
  60 }
  61
  62 static int max5821_set_powerdown_mode(struct iio_dev *indio_dev,
  63                                       const struct iio_chan_spec *chan,
  64                                       unsigned int mode)
  65 {
  66         struct max5821_data *st = iio_priv(indio_dev);
  67
  68         st->powerdown_mode[chan->channel] = mode;
  69
  70         return 0;
  71 }
  72
  73 static const struct iio_enum max5821_powerdown_mode_enum = {
  74         .items = max5821_powerdown_modes,
  75         .num_items = ARRAY_SIZE(max5821_powerdown_modes),
  76         .get = max5821_get_powerdown_mode,
  77         .set = max5821_set_powerdown_mode,
  78 };
  79
  80 static ssize_t max5821_read_dac_powerdown(struct iio_dev *indio_dev,
  81                                           uintptr_t private,
  82                                           const struct iio_chan_spec *chan,
  83                                           char *buf)
  84 {
  85         struct max5821_data *st = iio_priv(indio_dev);
  86
  87         return sysfs_emit(buf, "%d\n", st->powerdown[chan->channel]);
  88 }
  89
  90 static int max5821_sync_powerdown_mode(struct max5821_data *data,
  91                                        const struct iio_chan_spec *chan)
  92 {
  93         u8 outbuf[2];
  94
  95         outbuf[0] = MAX5821_EXTENDED_COMMAND_MODE;
  96
  97         if (chan->channel == 0)
  98                 outbuf[1] = MAX5821_EXTENDED_DAC_A;
  99         else
 100                 outbuf[1] = MAX5821_EXTENDED_DAC_B;
 101
 102         if (data->powerdown[chan->channel])
 103                 outbuf[1] |= data->powerdown_mode[chan->channel] + 1;
 104         else
 105                 outbuf[1] |= MAX5821_EXTENDED_POWER_UP;
 106
 107         return i2c_master_send(data->client, outbuf, 2);
 108 }
 109
 110 static ssize_t max5821_write_dac_powerdown(struct iio_dev *indio_dev,
 111                                            uintptr_t private,
 112                                            const struct iio_chan_spec *chan,
 113                                            const char *buf, size_t len)
 114 {
 115         struct max5821_data *data = iio_priv(indio_dev);
 116         bool powerdown;
 117         int ret;
 118
 119         ret = kstrtobool(buf, &powerdown);
 120         if (ret)
 121                 return ret;
 122
 123         data->powerdown[chan->channel] = powerdown;
 124
 125         ret = max5821_sync_powerdown_mode(data, chan);
 126         if (ret < 0)
 127                 return ret;
 128
 129         return len;
 130 }
 131
 132 static const struct iio_chan_spec_ext_info max5821_ext_info[] = {
 133         {
 134                 .name = "powerdown",
 135                 .read = max5821_read_dac_powerdown,
 136                 .write = max5821_write_dac_powerdown,
 137                 .shared = IIO_SEPARATE,
 138         },
 139         IIO_ENUM("powerdown_mode", IIO_SEPARATE, &max5821_powerdown_mode_enum),
 140         IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, &max5821_powerdown_mode_enum),
 141         { },
 142 };
 143
 144 #define MAX5821_CHANNEL(chan) {                                 \
 145         .type = IIO_VOLTAGE,                                    \
 146         .indexed = 1,                                           \
 147         .output = 1,                                            \
 148         .channel = (chan),                                      \
 149         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 150         .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE),    \
 151         .ext_info = max5821_ext_info,                           \
 152 }
 153
 154 static const struct iio_chan_spec max5821_channels[] = {
 155         MAX5821_CHANNEL(0),
 156         MAX5821_CHANNEL(1)
 157 };
 158
 159 static const u8 max5821_read_dac_command[] = {
 160         MAX5821_READ_DAC_A_COMMAND,
 161         MAX5821_READ_DAC_B_COMMAND
 162 };
 163
 164 static const u8 max5821_load_dac_command[] = {
 165         MAX5821_LOAD_DAC_A_IN_REG_B,
 166         MAX5821_LOAD_DAC_B_IN_REG_A
 167 };
 168
 169 static int max5821_get_value(struct iio_dev *indio_dev,
 170                              int *val, int channel)
 171 {
 172         struct max5821_data *data = iio_priv(indio_dev);
 173         struct i2c_client *client = data->client;
 174         u8 outbuf[1];
 175         u8 inbuf[2];
 176         int ret;
 177
 178         if ((channel != 0) && (channel != 1))
 179                 return -EINVAL;
 180
 181         outbuf[0] = max5821_read_dac_command[channel];
 182
 183         mutex_lock(&data->lock);
 184
 185         ret = i2c_master_send(client, outbuf, 1);
 186         if (ret < 0) {
 187                 mutex_unlock(&data->lock);
 188                 return ret;
 189         } else if (ret != 1) {
 190                 mutex_unlock(&data->lock);
 191                 return -EIO;
 192         }
 193
 194         ret = i2c_master_recv(client, inbuf, 2);
 195         if (ret < 0) {
 196                 mutex_unlock(&data->lock);
 197                 return ret;
 198         } else if (ret != 2) {
 199                 mutex_unlock(&data->lock);
 200                 return -EIO;
 201         }
 202
 203         mutex_unlock(&data->lock);
 204
 205         *val = ((inbuf[0] & 0x0f) << 6) | (inbuf[1] >> 2);
 206
 207         return IIO_VAL_INT;
 208 }
 209
 210 static int max5821_set_value(struct iio_dev *indio_dev,
 211                              int val, int channel)
 212 {
 213         struct max5821_data *data = iio_priv(indio_dev);
 214         struct i2c_client *client = data->client;
 215         u8 outbuf[2];
 216         int ret;
 217
 218         if ((val < 0) || (val > 1023))
 219                 return -EINVAL;
 220
 221         if ((channel != 0) && (channel != 1))
 222                 return -EINVAL;
 223
 224         outbuf[0] = max5821_load_dac_command[channel];
 225         outbuf[0] |= val >> 6;
 226         outbuf[1] = (val & 0x3f) << 2;
 227
 228         ret = i2c_master_send(client, outbuf, 2);
 229         if (ret < 0)
 230                 return ret;
 231         else if (ret != 2)
 232                 return -EIO;
 233         else
 234                 return 0;
 235 }
 236
 237 static int max5821_read_raw(struct iio_dev *indio_dev,
 238                            struct iio_chan_spec const *chan,
 239                            int *val, int *val2, long mask)
 240 {
 241         struct max5821_data *data = iio_priv(indio_dev);
 242
 243         switch (mask) {
 244         case IIO_CHAN_INFO_RAW:
 245                 return max5821_get_value(indio_dev, val, chan->channel);
 246         case IIO_CHAN_INFO_SCALE:
 247                 *val = data->vref_mv;
 248                 *val2 = 10;
 249                 return IIO_VAL_FRACTIONAL_LOG2;
 250         default:
 251                 return -EINVAL;
 252         }
 253 }
 254
 255 static int max5821_write_raw(struct iio_dev *indio_dev,
 256                              struct iio_chan_spec const *chan,
 257                              int val, int val2, long mask)
 258 {
 259         if (val2 != 0)
 260                 return -EINVAL;
 261
 262         switch (mask) {
 263         case IIO_CHAN_INFO_RAW:
 264                 return max5821_set_value(indio_dev, val, chan->channel);
 265         default:
 266                 return -EINVAL;
 267         }
 268 }
 269
 270 static int max5821_suspend(struct device *dev)
 271 {
 272         u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
 273                          MAX5821_EXTENDED_DAC_A |
 274                          MAX5821_EXTENDED_DAC_B |
 275                          MAX5821_EXTENDED_POWER_DOWN_MODE2 };
 276
 277         return i2c_master_send(to_i2c_client(dev), outbuf, 2);
 278 }
 279
 280 static int max5821_resume(struct device *dev)
 281 {
 282         u8 outbuf[2] = { MAX5821_EXTENDED_COMMAND_MODE,
 283                          MAX5821_EXTENDED_DAC_A |
 284                          MAX5821_EXTENDED_DAC_B |
 285                          MAX5821_EXTENDED_POWER_UP };
 286
 287         return i2c_master_send(to_i2c_client(dev), outbuf, 2);
 288 }
 289
 290 static DEFINE_SIMPLE_DEV_PM_OPS(max5821_pm_ops, max5821_suspend,
 291                                 max5821_resume);
 292
 293 static const struct iio_info max5821_info = {
 294         .read_raw = max5821_read_raw,
 295         .write_raw = max5821_write_raw,
 296 };
 297
 298 static void max5821_regulator_disable(void *reg)
 299 {
 300         regulator_disable(reg);
 301 }
 302
 303 static int max5821_probe(struct i2c_client *client)
 304 {
 305         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 306         struct max5821_data *data;
 307         struct iio_dev *indio_dev;
 308         u32 tmp;
 309         int ret;
 310
 311         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 312         if (!indio_dev)
 313                 return -ENOMEM;
 314         data = iio_priv(indio_dev);
 315         data->client = client;
 316         mutex_init(&data->lock);
 317
 318         /* max5821 start in powerdown mode 100Kohm to ground */
 319         for (tmp = 0; tmp < MAX5821_MAX_DAC_CHANNELS; tmp++) {
 320                 data->powerdown[tmp] = true;
 321                 data->powerdown_mode[tmp] = MAX5821_100KOHM_TO_GND;
 322         }
 323
 324         data->vref_reg = devm_regulator_get(&client->dev, "vref");
 325         if (IS_ERR(data->vref_reg))
 326                 return dev_err_probe(&client->dev, PTR_ERR(data->vref_reg),
 327                                      "Failed to get vref regulator\n");
 328
 329         ret = regulator_enable(data->vref_reg);
 330         if (ret) {
 331                 dev_err(&client->dev,
 332                         "Failed to enable vref regulator: %d\n", ret);
 333                 return ret;
 334         }
 335
 336         ret = devm_add_action_or_reset(&client->dev, max5821_regulator_disable,
 337                                        data->vref_reg);
 338         if (ret) {
 339                 dev_err(&client->dev,
 340                         "Failed to add action to managed regulator: %d\n", ret);
 341                 return ret;
 342         }
 343
 344         ret = regulator_get_voltage(data->vref_reg);
 345         if (ret < 0) {
 346                 dev_err(&client->dev,
 347                         "Failed to get voltage on regulator: %d\n", ret);
 348                 return ret;
 349         }
 350
 351         data->vref_mv = ret / 1000;
 352
 353         indio_dev->name = id->name;
 354         indio_dev->num_channels = ARRAY_SIZE(max5821_channels);
 355         indio_dev->channels = max5821_channels;
 356         indio_dev->modes = INDIO_DIRECT_MODE;
 357         indio_dev->info = &max5821_info;
 358
 359         return devm_iio_device_register(&client->dev, indio_dev);
 360 }
 361
 362 static const struct i2c_device_id max5821_id[] = {
 363         { "max5821", ID_MAX5821 },
 364         { }
 365 };
 366 MODULE_DEVICE_TABLE(i2c, max5821_id);
 367
 368 static const struct of_device_id max5821_of_match[] = {
 369         { .compatible = "maxim,max5821" },
 370         { }
 371 };
 372 MODULE_DEVICE_TABLE(of, max5821_of_match);
 373
 374 static struct i2c_driver max5821_driver = {
 375         .driver = {
 376                 .name   = "max5821",
 377                 .of_match_table = max5821_of_match,
 378                 .pm     = pm_sleep_ptr(&max5821_pm_ops),
 379         },
 380         .probe          = max5821_probe,
 381         .id_table       = max5821_id,
 382 };
 383 module_i2c_driver(max5821_driver);
 384
 385 MODULE_AUTHOR("Philippe Reynes <tremyfr@yahoo.fr>");
 386 MODULE_DESCRIPTION("MAX5821 DAC");
 387 MODULE_LICENSE("GPL v2");