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_device.h>
  23 #include <linux/of.h>
  24
  25 #include <linux/iio/iio.h>
  26 #include <linux/iio/sysfs.h>
  27
  28 #include <linux/iio/dac/mcp4725.h>
  29
  30 #define MCP4725_DRV_NAME "mcp4725"
  31
  32 #define MCP472X_REF_VDD                 0x00
  33 #define MCP472X_REF_VREF_UNBUFFERED     0x02
  34 #define MCP472X_REF_VREF_BUFFERED       0x03
  35
  36 struct mcp4725_data {
  37         struct i2c_client *client;
  38         int id;
  39         unsigned ref_mode;
  40         bool vref_buffered;
  41         u16 dac_value;
  42         bool powerdown;
  43         unsigned powerdown_mode;
  44         struct regulator *vdd_reg;
  45         struct regulator *vref_reg;
  46 };
  47
  48 static int mcp4725_suspend(struct device *dev)
  49 {
  50         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  51                 to_i2c_client(dev)));
  52         u8 outbuf[2];
  53
  54         outbuf[0] = (data->powerdown_mode + 1) << 4;
  55         outbuf[1] = 0;
  56         data->powerdown = true;
  57
  58         return i2c_master_send(data->client, outbuf, 2);
  59 }
  60
  61 static int mcp4725_resume(struct device *dev)
  62 {
  63         struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
  64                 to_i2c_client(dev)));
  65         u8 outbuf[2];
  66
  67         /* restore previous DAC value */
  68         outbuf[0] = (data->dac_value >> 8) & 0xf;
  69         outbuf[1] = data->dac_value & 0xff;
  70         data->powerdown = false;
  71
  72         return i2c_master_send(data->client, outbuf, 2);
  73 }
  74
  75 #ifdef CONFIG_PM_SLEEP
  76 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
  77 #define MCP4725_PM_OPS (&mcp4725_pm_ops)
  78 #else
  79 #define MCP4725_PM_OPS NULL
  80 #endif
  81
  82 static ssize_t mcp4725_store_eeprom(struct device *dev,
  83         struct device_attribute *attr, const char *buf, size_t len)
  84 {
  85         struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  86         struct mcp4725_data *data = iio_priv(indio_dev);
  87         int tries = 20;
  88         u8 inoutbuf[3];
  89         bool state;
  90         int ret;
  91
  92         ret = strtobool(buf, &state);
  93         if (ret < 0)
  94                 return ret;
  95
  96         if (!state)
  97                 return 0;
  98
  99         inoutbuf[0] = 0x60; /* write EEPROM */
 100         inoutbuf[0] |= data->ref_mode << 3;
 101         inoutbuf[1] = data->dac_value >> 4;
 102         inoutbuf[2] = (data->dac_value & 0xf) << 4;
 103
 104         ret = i2c_master_send(data->client, inoutbuf, 3);
 105         if (ret < 0)
 106                 return ret;
 107         else if (ret != 3)
 108                 return -EIO;
 109
 110         /* wait for write complete, takes up to 50ms */
 111         while (tries--) {
 112                 msleep(20);
 113                 ret = i2c_master_recv(data->client, inoutbuf, 3);
 114                 if (ret < 0)
 115                         return ret;
 116                 else if (ret != 3)
 117                         return -EIO;
 118
 119                 if (inoutbuf[0] & 0x80)
 120                         break;
 121         }
 122
 123         if (tries < 0) {
 124                 dev_err(&data->client->dev,
 125                         "mcp4725_store_eeprom() failed, incomplete\n");
 126                 return -EIO;
 127         }
 128
 129         return len;
 130 }
 131
 132 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
 133
 134 static struct attribute *mcp4725_attributes[] = {
 135         &iio_dev_attr_store_eeprom.dev_attr.attr,
 136         NULL,
 137 };
 138
 139 static const struct attribute_group mcp4725_attribute_group = {
 140         .attrs = mcp4725_attributes,
 141 };
 142
 143 static const char * const mcp4725_powerdown_modes[] = {
 144         "1kohm_to_gnd",
 145         "100kohm_to_gnd",
 146         "500kohm_to_gnd"
 147 };
 148
 149 static const char * const mcp4726_powerdown_modes[] = {
 150         "1kohm_to_gnd",
 151         "125kohm_to_gnd",
 152         "640kohm_to_gnd"
 153 };
 154
 155 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
 156         const struct iio_chan_spec *chan)
 157 {
 158         struct mcp4725_data *data = iio_priv(indio_dev);
 159
 160         return data->powerdown_mode;
 161 }
 162
 163 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
 164         const struct iio_chan_spec *chan, unsigned mode)
 165 {
 166         struct mcp4725_data *data = iio_priv(indio_dev);
 167
 168         data->powerdown_mode = mode;
 169
 170         return 0;
 171 }
 172
 173 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
 174         uintptr_t private, const struct iio_chan_spec *chan, char *buf)
 175 {
 176         struct mcp4725_data *data = iio_priv(indio_dev);
 177
 178         return sprintf(buf, "%d\n", data->powerdown);
 179 }
 180
 181 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
 182          uintptr_t private, const struct iio_chan_spec *chan,
 183          const char *buf, size_t len)
 184 {
 185         struct mcp4725_data *data = iio_priv(indio_dev);
 186         bool state;
 187         int ret;
 188
 189         ret = strtobool(buf, &state);
 190         if (ret)
 191                 return ret;
 192
 193         if (state)
 194                 ret = mcp4725_suspend(&data->client->dev);
 195         else
 196                 ret = mcp4725_resume(&data->client->dev);
 197         if (ret < 0)
 198                 return ret;
 199
 200         return len;
 201 }
 202
 203 enum chip_id {
 204         MCP4725,
 205         MCP4726,
 206 };
 207
 208 static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
 209         [MCP4725] = {
 210                 .items = mcp4725_powerdown_modes,
 211                 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
 212                 .get = mcp4725_get_powerdown_mode,
 213                 .set = mcp4725_set_powerdown_mode,
 214         },
 215         [MCP4726] = {
 216                 .items = mcp4726_powerdown_modes,
 217                 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
 218                 .get = mcp4725_get_powerdown_mode,
 219                 .set = mcp4725_set_powerdown_mode,
 220         },
 221 };
 222
 223 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
 224         {
 225                 .name = "powerdown",
 226                 .read = mcp4725_read_powerdown,
 227                 .write = mcp4725_write_powerdown,
 228                 .shared = IIO_SEPARATE,
 229         },
 230         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 231                         &mcp472x_powerdown_mode_enum[MCP4725]),
 232         IIO_ENUM_AVAILABLE("powerdown_mode",
 233                         &mcp472x_powerdown_mode_enum[MCP4725]),
 234         { },
 235 };
 236
 237 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
 238         {
 239                 .name = "powerdown",
 240                 .read = mcp4725_read_powerdown,
 241                 .write = mcp4725_write_powerdown,
 242                 .shared = IIO_SEPARATE,
 243         },
 244         IIO_ENUM("powerdown_mode", IIO_SEPARATE,
 245                         &mcp472x_powerdown_mode_enum[MCP4726]),
 246         IIO_ENUM_AVAILABLE("powerdown_mode",
 247                         &mcp472x_powerdown_mode_enum[MCP4726]),
 248         { },
 249 };
 250
 251 static const struct iio_chan_spec mcp472x_channel[] = {
 252         [MCP4725] = {
 253                 .type           = IIO_VOLTAGE,
 254                 .indexed        = 1,
 255                 .output         = 1,
 256                 .channel        = 0,
 257                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 258                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 259                 .ext_info       = mcp4725_ext_info,
 260         },
 261         [MCP4726] = {
 262                 .type           = IIO_VOLTAGE,
 263                 .indexed        = 1,
 264                 .output         = 1,
 265                 .channel        = 0,
 266                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 267                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 268                 .ext_info       = mcp4726_ext_info,
 269         },
 270 };
 271
 272 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
 273 {
 274         struct mcp4725_data *data = iio_priv(indio_dev);
 275         u8 outbuf[2];
 276         int ret;
 277
 278         if (val >= (1 << 12) || val < 0)
 279                 return -EINVAL;
 280
 281         outbuf[0] = (val >> 8) & 0xf;
 282         outbuf[1] = val & 0xff;
 283
 284         ret = i2c_master_send(data->client, outbuf, 2);
 285         if (ret < 0)
 286                 return ret;
 287         else if (ret != 2)
 288                 return -EIO;
 289         else
 290                 return 0;
 291 }
 292
 293 static int mcp4726_set_cfg(struct iio_dev *indio_dev)
 294 {
 295         struct mcp4725_data *data = iio_priv(indio_dev);
 296         u8 outbuf[3];
 297         int ret;
 298
 299         outbuf[0] = 0x40;
 300         outbuf[0] |= data->ref_mode << 3;
 301         if (data->powerdown)
 302                 outbuf[0] |= data->powerdown << 1;
 303         outbuf[1] = data->dac_value >> 4;
 304         outbuf[2] = (data->dac_value & 0xf) << 4;
 305
 306         ret = i2c_master_send(data->client, outbuf, 3);
 307         if (ret < 0)
 308                 return ret;
 309         else if (ret != 3)
 310                 return -EIO;
 311         else
 312                 return 0;
 313 }
 314
 315 static int mcp4725_read_raw(struct iio_dev *indio_dev,
 316                            struct iio_chan_spec const *chan,
 317                            int *val, int *val2, long mask)
 318 {
 319         struct mcp4725_data *data = iio_priv(indio_dev);
 320         int ret;
 321
 322         switch (mask) {
 323         case IIO_CHAN_INFO_RAW:
 324                 *val = data->dac_value;
 325                 return IIO_VAL_INT;
 326         case IIO_CHAN_INFO_SCALE:
 327                 if (data->ref_mode == MCP472X_REF_VDD)
 328                         ret = regulator_get_voltage(data->vdd_reg);
 329                 else
 330                         ret = regulator_get_voltage(data->vref_reg);
 331
 332                 if (ret < 0)
 333                         return ret;
 334
 335                 *val = ret / 1000;
 336                 *val2 = 12;
 337                 return IIO_VAL_FRACTIONAL_LOG2;
 338         }
 339         return -EINVAL;
 340 }
 341
 342 static int mcp4725_write_raw(struct iio_dev *indio_dev,
 343                                struct iio_chan_spec const *chan,
 344                                int val, int val2, long mask)
 345 {
 346         struct mcp4725_data *data = iio_priv(indio_dev);
 347         int ret;
 348
 349         switch (mask) {
 350         case IIO_CHAN_INFO_RAW:
 351                 ret = mcp4725_set_value(indio_dev, val);
 352                 data->dac_value = val;
 353                 break;
 354         default:
 355                 ret = -EINVAL;
 356                 break;
 357         }
 358
 359         return ret;
 360 }
 361
 362 static const struct iio_info mcp4725_info = {
 363         .read_raw = mcp4725_read_raw,
 364         .write_raw = mcp4725_write_raw,
 365         .attrs = &mcp4725_attribute_group,
 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         if (client->dev.of_node)
 410                 data->id = (enum chip_id)of_device_get_match_data(&client->dev);
 411         else
 412                 data->id = id->driver_data;
 413         pdata = dev_get_platdata(&client->dev);
 414
 415         if (!pdata) {
 416                 err = mcp4725_probe_dt(&client->dev, &pdata_dt);
 417                 if (err) {
 418                         dev_err(&client->dev,
 419                                 "invalid platform or devicetree data");
 420                         return err;
 421                 }
 422                 pdata = &pdata_dt;
 423         }
 424
 425         if (data->id == MCP4725 && pdata->use_vref) {
 426                 dev_err(&client->dev,
 427                         "external reference is unavailable on MCP4725");
 428                 return -EINVAL;
 429         }
 430
 431         if (!pdata->use_vref && pdata->vref_buffered) {
 432                 dev_err(&client->dev,
 433                         "buffering is unavailable on the internal reference");
 434                 return -EINVAL;
 435         }
 436
 437         if (!pdata->use_vref)
 438                 data->ref_mode = MCP472X_REF_VDD;
 439         else
 440                 data->ref_mode = pdata->vref_buffered ?
 441                         MCP472X_REF_VREF_BUFFERED :
 442                         MCP472X_REF_VREF_UNBUFFERED;
 443
 444         data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
 445         if (IS_ERR(data->vdd_reg))
 446                 return PTR_ERR(data->vdd_reg);
 447
 448         err = regulator_enable(data->vdd_reg);
 449         if (err)
 450                 return err;
 451
 452         if (pdata->use_vref) {
 453                 data->vref_reg = devm_regulator_get(&client->dev, "vref");
 454                 if (IS_ERR(data->vref_reg)) {
 455                         err = PTR_ERR(data->vref_reg);
 456                         goto err_disable_vdd_reg;
 457                 }
 458
 459                 err = regulator_enable(data->vref_reg);
 460                 if (err)
 461                         goto err_disable_vdd_reg;
 462         }
 463
 464         indio_dev->dev.parent = &client->dev;
 465         indio_dev->name = id->name;
 466         indio_dev->info = &mcp4725_info;
 467         indio_dev->channels = &mcp472x_channel[id->driver_data];
 468         indio_dev->num_channels = 1;
 469         indio_dev->modes = INDIO_DIRECT_MODE;
 470
 471         /* read current DAC value and settings */
 472         err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
 473
 474         if (err < 0) {
 475                 dev_err(&client->dev, "failed to read DAC value");
 476                 goto err_disable_vref_reg;
 477         }
 478         pd = (inbuf[0] >> 1) & 0x3;
 479         data->powerdown = pd > 0;
 480         data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
 481         data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
 482         if (data->id == MCP4726)
 483                 ref = (inbuf[3] >> 3) & 0x3;
 484
 485         if (data->id == MCP4726 && ref != data->ref_mode) {
 486                 dev_info(&client->dev,
 487                         "voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
 488                         data->ref_mode, ref, data->ref_mode);
 489                 err = mcp4726_set_cfg(indio_dev);
 490                 if (err < 0)
 491                         goto err_disable_vref_reg;
 492         }
 493
 494         err = iio_device_register(indio_dev);
 495         if (err)
 496                 goto err_disable_vref_reg;
 497
 498         return 0;
 499
 500 err_disable_vref_reg:
 501         if (data->vref_reg)
 502                 regulator_disable(data->vref_reg);
 503
 504 err_disable_vdd_reg:
 505         regulator_disable(data->vdd_reg);
 506
 507         return err;
 508 }
 509
 510 static int mcp4725_remove(struct i2c_client *client)
 511 {
 512         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 513         struct mcp4725_data *data = iio_priv(indio_dev);
 514
 515         iio_device_unregister(indio_dev);
 516
 517         if (data->vref_reg)
 518                 regulator_disable(data->vref_reg);
 519         regulator_disable(data->vdd_reg);
 520
 521         return 0;
 522 }
 523
 524 static const struct i2c_device_id mcp4725_id[] = {
 525         { "mcp4725", MCP4725 },
 526         { "mcp4726", MCP4726 },
 527         { }
 528 };
 529 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
 530
 531 #ifdef CONFIG_OF
 532 static const struct of_device_id mcp4725_of_match[] = {
 533         {
 534                 .compatible = "microchip,mcp4725",
 535                 .data = (void *)MCP4725
 536         },
 537         {
 538                 .compatible = "microchip,mcp4726",
 539                 .data = (void *)MCP4726
 540         },
 541         { }
 542 };
 543 MODULE_DEVICE_TABLE(of, mcp4725_of_match);
 544 #endif
 545
 546 static struct i2c_driver mcp4725_driver = {
 547         .driver = {
 548                 .name   = MCP4725_DRV_NAME,
 549                 .of_match_table = of_match_ptr(mcp4725_of_match),
 550                 .pm     = MCP4725_PM_OPS,
 551         },
 552         .probe          = mcp4725_probe,
 553         .remove         = mcp4725_remove,
 554         .id_table       = mcp4725_id,
 555 };
 556 module_i2c_driver(mcp4725_driver);
 557
 558 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
 559 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC");
 560 MODULE_LICENSE("GPL");