drivers/iio/dac/mcp4725.c

   1 /*
   2  * mcp4725.c - Support for Microchip MCP4725/6
   3  *
   4  * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
   5  *
   6  * Based on max517 by Roland Stigge <stigge@antcom.de>
   7  *
   8  * This file is subject to the terms and conditions of version 2 of
   9  * the GNU General Public License.  See the file COPYING in the main
  10  * directory of this archive for more details.
  11  *
  12  * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
  13  * (7-bit I2C slave address 0x60, the three LSBs can be configured in
  14  * hardware)
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/i2c.h>
  19 #include <linux/err.h>
  20 #include <linux/delay.h>
  21 #include <linux/regulator/consumer.h>
  22 #include <linux/of.h>
  23
  24 #include <linux/iio/iio.h>
  25 #include <linux/iio/sysfs.h>
  26
  27 #include <linux/iio/dac/mcp4725.h>
  28
  29 #define MCP4725_DRV_NAME "mcp4725"
  30
  31 #define MCP472X_REF_VDD                 0x00
  32 #define MCP472X_REF_VREF_UNBUFFERED     0x02
  33 #define MCP472X_REF_VREF_BUFFERED       0x03
  34
  35 struct mcp4725_data {
  36         struct i2c_client *client;
  37         int id;
  38         unsigned ref_mode;
  39         bool vref_buffered;
  40         u16 dac_value;
  41         bool powerdown;
  42         unsigned powerdown_mode;
  43         struct regulator *vdd_reg;
  44         struct regulator *vref_reg;
  45 };
  46
  47 static int mcp4725_suspend(struct device *dev)
  48 {
  49         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  50                 to_i2c_client(dev)));
  51         u8 outbuf[2];
  52
  53         outbuf[0] = (data->powerdown_mode + 1) << 4;
  54         outbuf[1] = 0;
  55         data->powerdown = true;
  56
  57         return i2c_master_send(data->client, outbuf, 2);
  58 }
  59
  60 static int mcp4725_resume(struct device *dev)
  61 {
  62         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  63                 to_i2c_client(dev)));
  64         u8 outbuf[2];
  65
  66         /* restore previous DAC value */
  67         outbuf[0] = (data->dac_value >> 8) & 0xf;
  68         outbuf[1] = data->dac_value & 0xff;
  69         data->powerdown = false;
  70
  71         return i2c_master_send(data->client, outbuf, 2);
  72 }
  73
  74 #ifdef CONFIG_PM_SLEEP
  75 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
  76 #define MCP4725_PM_OPS (&mcp4725_pm_ops)
  77 #else
  78 #define MCP4725_PM_OPS NULL
  79 #endif
  80
  81 static ssize_t mcp4725_store_eeprom(struct device *dev,
  82         struct device_attribute *attr, const char *buf, size_t len)
  83 {
  84         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  85         struct mcp4725_data *data = iio_priv(indio_dev);
  86         int tries = 20;
  87         u8 inoutbuf[3];
  88         bool state;
  89         int ret;
  90
  91         ret = strtobool(buf, &state);
  92         if (ret < 0)
  93                 return ret;
  94
  95         if (!state)
  96                 return 0;
  97
  98         inoutbuf[0] = 0x60; /* write EEPROM */
  99         inoutbuf[0] |= data->ref_mode << 3;
 100         inoutbuf[1] = data->dac_value >> 4;
 101         inoutbuf[2] = (data->dac_value & 0xf) << 4;
 102
 103         ret = i2c_master_send(data->client, inoutbuf, 3);
 104         if (ret < 0)
 105                 return ret;
 106         else if (ret != 3)
 107                 return -EIO;
 108
 109         /* wait for write complete, takes up to 50ms */
 110         while (tries--) {
 111                 msleep(20);
 112                 ret = i2c_master_recv(data->client, inoutbuf, 3);
 113                 if (ret < 0)
 114                         return ret;
 115                 else if (ret != 3)
 116                         return -EIO;
 117
 118                 if (inoutbuf[0] & 0x80)
 119                         break;
 120         }
 121
 122         if (tries < 0) {
 123                 dev_err(&data->client->dev,
 124                         "mcp4725_store_eeprom() failed, incomplete\n");
 125                 return -EIO;
 126         }
 127
 128         return len;
 129 }
 130
 131 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
 132
 133 static struct attribute *mcp4725_attributes[] = {
 134         &iio_dev_attr_store_eeprom.dev_attr.attr,
 135         NULL,
 136 };
 137
 138 static const struct attribute_group mcp4725_attribute_group = {
 139         .attrs = mcp4725_attributes,
 140 };
 141
 142 static const char * const mcp4725_powerdown_modes[] = {
 143         "1kohm_to_gnd",
 144         "100kohm_to_gnd",
 145         "500kohm_to_gnd"
 146 };
 147
 148 static const char * const mcp4726_powerdown_modes[] = {
 149         "1kohm_to_gnd",
 150         "125kohm_to_gnd",
 151         "640kohm_to_gnd"
 152 };
 153
 154 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
 155         const struct iio_chan_spec *chan)
 156 {
 157         struct mcp4725_data *data = iio_priv(indio_dev);
 158
 159         return data->powerdown_mode;
 160 }
 161
 162 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
 163         const struct iio_chan_spec *chan, unsigned mode)
 164 {
 165         struct mcp4725_data *data = iio_priv(indio_dev);
 166
 167         data->powerdown_mode = mode;
 168
 169         return 0;
 170 }
 171
 172 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
 173         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 174 {
 175         struct mcp4725_data *data = iio_priv(indio_dev);
 176
 177         return sprintf(buf, "%d\n", data->powerdown);
 178 }
 179
 180 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
 181          uintptr_t private, const struct iio_chan_spec *chan,
 182          const char *buf, size_t len)
 183 {
 184         struct mcp4725_data *data = iio_priv(indio_dev);
 185         bool state;
 186         int ret;
 187
 188         ret = strtobool(buf, &state);
 189         if (ret)
 190                 return ret;
 191
 192         if (state)
 193                 ret = mcp4725_suspend(&data->client->dev);
 194         else
 195                 ret = mcp4725_resume(&data->client->dev);
 196         if (ret < 0)
 197                 return ret;
 198
 199         return len;
 200 }
 201
 202 enum {
 203         MCP4725,
 204         MCP4726,
 205 };
 206
 207 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
 208         [MCP4725] = {
 209                 .items = mcp4725_powerdown_modes,
 210                 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
 211                 .get = mcp4725_get_powerdown_mode,
 212                 .set = mcp4725_set_powerdown_mode,
 213         },
 214         [MCP4726] = {
 215                 .items = mcp4726_powerdown_modes,
 216                 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
 217                 .get = mcp4725_get_powerdown_mode,
 218                 .set = mcp4725_set_powerdown_mode,
 219         },
 220 };
 221
 222 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
 223         {
 224                 .name = "powerdown",
 225                 .read = mcp4725_read_powerdown,
 226                 .write = mcp4725_write_powerdown,
 227                 .shared = IIO_SEPARATE,
 228         },
 229         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 230                         &mcp472x_powerdown_mode_enum[MCP4725]),
 231         IIO_ENUM_AVAILABLE("powerdown_mode",
 232                         &mcp472x_powerdown_mode_enum[MCP4725]),
 233         { },
 234 };
 235
 236 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
 237         {
 238                 .name = "powerdown",
 239                 .read = mcp4725_read_powerdown,
 240                 .write = mcp4725_write_powerdown,
 241                 .shared = IIO_SEPARATE,
 242         },
 243         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 244                         &mcp472x_powerdown_mode_enum[MCP4726]),
 245         IIO_ENUM_AVAILABLE("powerdown_mode",
 246                         &mcp472x_powerdown_mode_enum[MCP4726]),
 247         { },
 248 };
 249
 250 static const struct iio_chan_spec mcp472x_channel[] = {
 251         [MCP4725] = {
 252                 .type           = IIO_VOLTAGE,
 253                 .indexed        = 1,
 254                 .output         = 1,
 255                 .channel        = 0,
 256                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 257                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 258                 .ext_info       = mcp4725_ext_info,
 259         },
 260         [MCP4726] = {
 261                 .type           = IIO_VOLTAGE,
 262                 .indexed        = 1,
 263                 .output         = 1,
 264                 .channel        = 0,
 265                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 266                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 267                 .ext_info       = mcp4726_ext_info,
 268         },
 269 };
 270
 271 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
 272 {
 273         struct mcp4725_data *data = iio_priv(indio_dev);
 274         u8 outbuf[2];
 275         int ret;
 276
 277         if (val >= (1 << 12) || val < 0)
 278                 return -EINVAL;
 279
 280         outbuf[0] = (val >> 8) & 0xf;
 281         outbuf[1] = val & 0xff;
 282
 283         ret = i2c_master_send(data->client, outbuf, 2);
 284         if (ret < 0)
 285                 return ret;
 286         else if (ret != 2)
 287                 return -EIO;
 288         else
 289                 return 0;
 290 }
 291
 292 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
 293 {
 294         struct mcp4725_data *data = iio_priv(indio_dev);
 295         u8 outbuf[3];
 296         int ret;
 297
 298         outbuf[0] = 0x40;
 299         outbuf[0] |= data->ref_mode << 3;
 300         if (data->powerdown)
 301                 outbuf[0] |= data->powerdown << 1;
 302         outbuf[1] = data->dac_value >> 4;
 303         outbuf[2] = (data->dac_value & 0xf) << 4;
 304
 305         ret = i2c_master_send(data->client, outbuf, 3);
 306         if (ret < 0)
 307                 return ret;
 308         else if (ret != 3)
 309                 return -EIO;
 310         else
 311                 return 0;
 312 }
 313
 314 static int mcp4725_read_raw(struct iio_dev *indio_dev,
 315                            struct iio_chan_spec const *chan,
 316                            int *val, int *val2, long mask)
 317 {
 318         struct mcp4725_data *data = iio_priv(indio_dev);
 319         int ret;
 320
 321         switch (mask) {
 322         case IIO_CHAN_INFO_RAW:
 323                 *val = data->dac_value;
 324                 return IIO_VAL_INT;
 325         case IIO_CHAN_INFO_SCALE:
 326                 if (data->ref_mode == MCP472X_REF_VDD)
 327                         ret = regulator_get_voltage(data->vdd_reg);
 328                 else
 329                         ret = regulator_get_voltage(data->vref_reg);
 330
 331                 if (ret < 0)
 332                         return ret;
 333
 334                 *val = ret / 1000;
 335                 *val2 = 12;
 336                 return IIO_VAL_FRACTIONAL_LOG2;
 337         }
 338         return -EINVAL;
 339 }
 340
 341 static int mcp4725_write_raw(struct iio_dev *indio_dev,
 342                                struct iio_chan_spec const *chan,
 343                                int val, int val2, long mask)
 344 {
 345         struct mcp4725_data *data = iio_priv(indio_dev);
 346         int ret;
 347
 348         switch (mask) {
 349         case IIO_CHAN_INFO_RAW:
 350                 ret = mcp4725_set_value(indio_dev, val);
 351                 data->dac_value = val;
 352                 break;
 353         default:
 354                 ret = -EINVAL;
 355                 break;
 356         }
 357
 358         return ret;
 359 }
 360
 361 static const struct iio_info mcp4725_info = {
 362         .read_raw = mcp4725_read_raw,
 363         .write_raw = mcp4725_write_raw,
 364         .attrs = &mcp4725_attribute_group,
 365         .driver_module = THIS_MODULE,
 366 };
 367
 368 #ifdef CONFIG_OF
 369 static int mcp4725_probe_dt(struct device *dev,
 370                             struct mcp4725_platform_data *pdata)
 371 {
 372         struct device_node *np = dev->of_node;
 373
 374         if (!np)
 375                 return -ENODEV;
 376
 377         /* check if is the vref-supply defined */
 378         pdata->use_vref = of_property_read_bool(np, "vref-supply");
 379         pdata->vref_buffered =
 380                 of_property_read_bool(np, "microchip,vref-buffered");
 381
 382         return 0;
 383 }
 384 #else
 385 static int mcp4725_probe_dt(struct device *dev,
 386                             struct mcp4725_platform_data *platform_data)
 387 {
 388         return -ENODEV;
 389 }
 390 #endif
 391
 392 static int mcp4725_probe(struct i2c_client *client,
 393                          const struct i2c_device_id *id)
 394 {
 395         struct mcp4725_data *data;
 396         struct iio_dev *indio_dev;
 397         struct mcp4725_platform_data *pdata, pdata_dt;
 398         u8 inbuf[4];
 399         u8 pd;
 400         u8 ref;
 401         int err;
 402
 403         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 404         if (indio_dev == NULL)
 405                 return -ENOMEM;
 406         data = iio_priv(indio_dev);
 407         i2c_set_clientdata(client, indio_dev);
 408         data->client = client;
 409         data->id = id->driver_data;
 410         pdata = dev_get_platdata(&client->dev);
 411
 412         if (!pdata) {
 413                 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
 414                 if (err) {
 415                         dev_err(&client->dev,
 416                                 "invalid platform or devicetree data");
 417                         return err;
 418                 }
 419                 pdata = &pdata_dt;
 420         }
 421
 422         if (data->id == MCP4725 && pdata->use_vref) {
 423                 dev_err(&client->dev,
 424                         "external reference is unavailable on MCP4725");
 425                 return -EINVAL;
 426         }
 427
 428         if (!pdata->use_vref && pdata->vref_buffered) {
 429                 dev_err(&client->dev,
 430                         "buffering is unavailable on the internal reference");
 431                 return -EINVAL;
 432         }
 433
 434         if (!pdata->use_vref)
 435                 data->ref_mode = MCP472X_REF_VDD;
 436         else
 437                 data->ref_mode = pdata->vref_buffered ?
 438                         MCP472X_REF_VREF_BUFFERED :
 439                         MCP472X_REF_VREF_UNBUFFERED;
 440
 441         data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
 442         if (IS_ERR(data->vdd_reg))
 443                 return PTR_ERR(data->vdd_reg);
 444
 445         err = regulator_enable(data->vdd_reg);
 446         if (err)
 447                 return err;
 448
 449         if (pdata->use_vref) {
 450                 data->vref_reg = devm_regulator_get(&client->dev, "vref");
 451                 if (IS_ERR(data->vref_reg)) {
 452                         err = PTR_ERR(data->vref_reg);
 453                         goto err_disable_vdd_reg;
 454                 }
 455
 456                 err = regulator_enable(data->vref_reg);
 457                 if (err)
 458                         goto err_disable_vdd_reg;
 459         }
 460
 461         indio_dev->dev.parent = &client->dev;
 462         indio_dev->name = id->name;
 463         indio_dev->info = &mcp4725_info;
 464         indio_dev->channels = &mcp472x_channel[id->driver_data];
 465         indio_dev->num_channels = 1;
 466         indio_dev->modes = INDIO_DIRECT_MODE;
 467
 468         /* read current DAC value and settings */
 469         err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
 470
 471         if (err < 0) {
 472                 dev_err(&client->dev, "failed to read DAC value");
 473                 goto err_disable_vref_reg;
 474         }
 475         pd = (inbuf[0] >> 1) & 0x3;
 476         data->powerdown = pd > 0 ? true : false;
 477         data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
 478         data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
 479         if (data->id == MCP4726)
 480                 ref = (inbuf[3] >> 3) & 0x3;
 481
 482         if (data->id == MCP4726 && ref != data->ref_mode) {
 483                 dev_info(&client->dev,
 484                         "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
 485                         data->ref_mode, ref, data->ref_mode);
 486                 err = mcp4726_set_cfg(indio_dev);
 487                 if (err < 0)
 488                         goto err_disable_vref_reg;
 489         }
 490
 491         err = iio_device_register(indio_dev);
 492         if (err)
 493                 goto err_disable_vref_reg;
 494
 495         return 0;
 496
 497 err_disable_vref_reg:
 498         if (data->vref_reg)
 499                 regulator_disable(data->vref_reg);
 500
 501 err_disable_vdd_reg:
 502         regulator_disable(data->vdd_reg);
 503
 504         return err;
 505 }
 506
 507 static int mcp4725_remove(struct i2c_client *client)
 508 {
 509         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 510         struct mcp4725_data *data = iio_priv(indio_dev);
 511
 512         iio_device_unregister(indio_dev);
 513
 514         if (data->vref_reg)
 515                 regulator_disable(data->vref_reg);
 516         regulator_disable(data->vdd_reg);
 517
 518         return 0;
 519 }
 520
 521 static const struct i2c_device_id mcp4725_id[] = {
 522         { "mcp4725", MCP4725 },
 523         { "mcp4726", MCP4726 },
 524         { }
 525 };
 526 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
 527
 528 static struct i2c_driver mcp4725_driver = {
 529         .driver = {
 530                 .name   = MCP4725_DRV_NAME,
 531                 .pm     = MCP4725_PM_OPS,
 532         },
 533         .probe          = mcp4725_probe,
 534         .remove         = mcp4725_remove,
 535         .id_table       = mcp4725_id,
 536 };
 537 module_i2c_driver(mcp4725_driver);
 538
 539 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 540 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
 541 MODULE_LICENSE("GPL");