1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * mcp4725.c - Support for Microchip MCP4725/6 4 * 5 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net> 6 * 7 * Based on max517 by Roland Stigge <stigge@antcom.de> 8 * 9 * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC) 10 * (7-bit I2C slave address 0x60, the three LSBs can be configured in 11 * hardware) 12 */ 13 14 #include <linux/module.h> 15 #include <linux/i2c.h> 16 #include <linux/err.h> 17 #include <linux/delay.h> 18 #include <linux/regulator/consumer.h> 19 #include <linux/mod_devicetable.h> 20 #include <linux/property.h> 21 22 #include <linux/iio/iio.h> 23 #include <linux/iio/sysfs.h> 24 25 #include <linux/iio/dac/mcp4725.h> 26 27 #define MCP4725_DRV_NAME "mcp4725" 28 29 #define MCP472X_REF_VDD 0x00 30 #define MCP472X_REF_VREF_UNBUFFERED 0x02 31 #define MCP472X_REF_VREF_BUFFERED 0x03 32 33 struct mcp4725_data { 34 struct i2c_client *client; 35 int id; 36 unsigned ref_mode; 37 bool vref_buffered; 38 u16 dac_value; 39 bool powerdown; 40 unsigned powerdown_mode; 41 struct regulator *vdd_reg; 42 struct regulator *vref_reg; 43 }; 44 45 static int mcp4725_suspend(struct device *dev) 46 { 47 struct mcp4725_data *data = iio_priv(i2c_get_clientdata( 48 to_i2c_client(dev))); 49 u8 outbuf[2]; 50 int ret; 51 52 outbuf[0] = (data->powerdown_mode + 1) << 4; 53 outbuf[1] = 0; 54 data->powerdown = true; 55 56 ret = i2c_master_send(data->client, outbuf, 2); 57 if (ret < 0) 58 return ret; 59 else if (ret != 2) 60 return -EIO; 61 return 0; 62 } 63 64 static int mcp4725_resume(struct device *dev) 65 { 66 struct mcp4725_data *data = iio_priv(i2c_get_clientdata( 67 to_i2c_client(dev))); 68 u8 outbuf[2]; 69 int ret; 70 71 /* restore previous DAC value */ 72 outbuf[0] = (data->dac_value >> 8) & 0xf; 73 outbuf[1] = data->dac_value & 0xff; 74 data->powerdown = false; 75 76 ret = i2c_master_send(data->client, outbuf, 2); 77 if (ret < 0) 78 return ret; 79 else if (ret != 2) 80 return -EIO; 81 return 0; 82 } 83 static DEFINE_SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, 84 mcp4725_resume); 85 86 static ssize_t mcp4725_store_eeprom(struct device *dev, 87 struct device_attribute *attr, const char *buf, size_t len) 88 { 89 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 90 struct mcp4725_data *data = iio_priv(indio_dev); 91 int tries = 20; 92 u8 inoutbuf[3]; 93 bool state; 94 int ret; 95 96 ret = kstrtobool(buf, &state); 97 if (ret < 0) 98 return ret; 99 100 if (!state) 101 return 0; 102 103 inoutbuf[0] = 0x60; /* write EEPROM */ 104 inoutbuf[0] |= data->ref_mode << 3; 105 inoutbuf[0] |= data->powerdown ? ((data->powerdown_mode + 1) << 1) : 0; 106 inoutbuf[1] = data->dac_value >> 4; 107 inoutbuf[2] = (data->dac_value & 0xf) << 4; 108 109 ret = i2c_master_send(data->client, inoutbuf, 3); 110 if (ret < 0) 111 return ret; 112 else if (ret != 3) 113 return -EIO; 114 115 /* wait for write complete, takes up to 50ms */ 116 while (tries--) { 117 msleep(20); 118 ret = i2c_master_recv(data->client, inoutbuf, 3); 119 if (ret < 0) 120 return ret; 121 else if (ret != 3) 122 return -EIO; 123 124 if (inoutbuf[0] & 0x80) 125 break; 126 } 127 128 if (tries < 0) { 129 dev_err(&data->client->dev, 130 "mcp4725_store_eeprom() failed, incomplete\n"); 131 return -EIO; 132 } 133 134 return len; 135 } 136 137 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0); 138 139 static struct attribute *mcp4725_attributes[] = { 140 &iio_dev_attr_store_eeprom.dev_attr.attr, 141 NULL, 142 }; 143 144 static const struct attribute_group mcp4725_attribute_group = { 145 .attrs = mcp4725_attributes, 146 }; 147 148 static const char * const mcp4725_powerdown_modes[] = { 149 "1kohm_to_gnd", 150 "100kohm_to_gnd", 151 "500kohm_to_gnd" 152 }; 153 154 static const char * const mcp4726_powerdown_modes[] = { 155 "1kohm_to_gnd", 156 "125kohm_to_gnd", 157 "640kohm_to_gnd" 158 }; 159 160 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev, 161 const struct iio_chan_spec *chan) 162 { 163 struct mcp4725_data *data = iio_priv(indio_dev); 164 165 return data->powerdown_mode; 166 } 167 168 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev, 169 const struct iio_chan_spec *chan, unsigned mode) 170 { 171 struct mcp4725_data *data = iio_priv(indio_dev); 172 173 data->powerdown_mode = mode; 174 175 return 0; 176 } 177 178 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev, 179 uintptr_t private, const struct iio_chan_spec *chan, char *buf) 180 { 181 struct mcp4725_data *data = iio_priv(indio_dev); 182 183 return sysfs_emit(buf, "%d\n", data->powerdown); 184 } 185 186 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev, 187 uintptr_t private, const struct iio_chan_spec *chan, 188 const char *buf, size_t len) 189 { 190 struct mcp4725_data *data = iio_priv(indio_dev); 191 bool state; 192 int ret; 193 194 ret = kstrtobool(buf, &state); 195 if (ret) 196 return ret; 197 198 if (state) 199 ret = mcp4725_suspend(&data->client->dev); 200 else 201 ret = mcp4725_resume(&data->client->dev); 202 if (ret < 0) 203 return ret; 204 205 return len; 206 } 207 208 enum chip_id { 209 MCP4725, 210 MCP4726, 211 }; 212 213 static const struct iio_enum mcp472x_powerdown_mode_enum[] = { 214 [MCP4725] = { 215 .items = mcp4725_powerdown_modes, 216 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes), 217 .get = mcp4725_get_powerdown_mode, 218 .set = mcp4725_set_powerdown_mode, 219 }, 220 [MCP4726] = { 221 .items = mcp4726_powerdown_modes, 222 .num_items = ARRAY_SIZE(mcp4726_powerdown_modes), 223 .get = mcp4725_get_powerdown_mode, 224 .set = mcp4725_set_powerdown_mode, 225 }, 226 }; 227 228 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = { 229 { 230 .name = "powerdown", 231 .read = mcp4725_read_powerdown, 232 .write = mcp4725_write_powerdown, 233 .shared = IIO_SEPARATE, 234 }, 235 IIO_ENUM("powerdown_mode", IIO_SEPARATE, 236 &mcp472x_powerdown_mode_enum[MCP4725]), 237 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, 238 &mcp472x_powerdown_mode_enum[MCP4725]), 239 { }, 240 }; 241 242 static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = { 243 { 244 .name = "powerdown", 245 .read = mcp4725_read_powerdown, 246 .write = mcp4725_write_powerdown, 247 .shared = IIO_SEPARATE, 248 }, 249 IIO_ENUM("powerdown_mode", IIO_SEPARATE, 250 &mcp472x_powerdown_mode_enum[MCP4726]), 251 IIO_ENUM_AVAILABLE("powerdown_mode", IIO_SHARED_BY_TYPE, 252 &mcp472x_powerdown_mode_enum[MCP4726]), 253 { }, 254 }; 255 256 static const struct iio_chan_spec mcp472x_channel[] = { 257 [MCP4725] = { 258 .type = IIO_VOLTAGE, 259 .indexed = 1, 260 .output = 1, 261 .channel = 0, 262 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 263 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 264 .ext_info = mcp4725_ext_info, 265 }, 266 [MCP4726] = { 267 .type = IIO_VOLTAGE, 268 .indexed = 1, 269 .output = 1, 270 .channel = 0, 271 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 272 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), 273 .ext_info = mcp4726_ext_info, 274 }, 275 }; 276 277 static int mcp4725_set_value(struct iio_dev *indio_dev, int val) 278 { 279 struct mcp4725_data *data = iio_priv(indio_dev); 280 u8 outbuf[2]; 281 int ret; 282 283 if (val >= (1 << 12) || val < 0) 284 return -EINVAL; 285 286 outbuf[0] = (val >> 8) & 0xf; 287 outbuf[1] = val & 0xff; 288 289 ret = i2c_master_send(data->client, outbuf, 2); 290 if (ret < 0) 291 return ret; 292 else if (ret != 2) 293 return -EIO; 294 else 295 return 0; 296 } 297 298 static int mcp4726_set_cfg(struct iio_dev *indio_dev) 299 { 300 struct mcp4725_data *data = iio_priv(indio_dev); 301 u8 outbuf[3]; 302 int ret; 303 304 outbuf[0] = 0x40; 305 outbuf[0] |= data->ref_mode << 3; 306 if (data->powerdown) 307 outbuf[0] |= data->powerdown << 1; 308 outbuf[1] = data->dac_value >> 4; 309 outbuf[2] = (data->dac_value & 0xf) << 4; 310 311 ret = i2c_master_send(data->client, outbuf, 3); 312 if (ret < 0) 313 return ret; 314 else if (ret != 3) 315 return -EIO; 316 else 317 return 0; 318 } 319 320 static int mcp4725_read_raw(struct iio_dev *indio_dev, 321 struct iio_chan_spec const *chan, 322 int *val, int *val2, long mask) 323 { 324 struct mcp4725_data *data = iio_priv(indio_dev); 325 int ret; 326 327 switch (mask) { 328 case IIO_CHAN_INFO_RAW: 329 *val = data->dac_value; 330 return IIO_VAL_INT; 331 case IIO_CHAN_INFO_SCALE: 332 if (data->ref_mode == MCP472X_REF_VDD) 333 ret = regulator_get_voltage(data->vdd_reg); 334 else 335 ret = regulator_get_voltage(data->vref_reg); 336 337 if (ret < 0) 338 return ret; 339 340 *val = ret / 1000; 341 *val2 = 12; 342 return IIO_VAL_FRACTIONAL_LOG2; 343 } 344 return -EINVAL; 345 } 346 347 static int mcp4725_write_raw(struct iio_dev *indio_dev, 348 struct iio_chan_spec const *chan, 349 int val, int val2, long mask) 350 { 351 struct mcp4725_data *data = iio_priv(indio_dev); 352 int ret; 353 354 switch (mask) { 355 case IIO_CHAN_INFO_RAW: 356 ret = mcp4725_set_value(indio_dev, val); 357 data->dac_value = val; 358 break; 359 default: 360 ret = -EINVAL; 361 break; 362 } 363 364 return ret; 365 } 366 367 static const struct iio_info mcp4725_info = { 368 .read_raw = mcp4725_read_raw, 369 .write_raw = mcp4725_write_raw, 370 .attrs = &mcp4725_attribute_group, 371 }; 372 373 static int mcp4725_probe_dt(struct device *dev, 374 struct mcp4725_platform_data *pdata) 375 { 376 /* check if is the vref-supply defined */ 377 pdata->use_vref = device_property_read_bool(dev, "vref-supply"); 378 pdata->vref_buffered = 379 device_property_read_bool(dev, "microchip,vref-buffered"); 380 381 return 0; 382 } 383 384 static int mcp4725_probe(struct i2c_client *client) 385 { 386 const struct i2c_device_id *id = i2c_client_get_device_id(client); 387 struct mcp4725_data *data; 388 struct iio_dev *indio_dev; 389 struct mcp4725_platform_data *pdata, pdata_dt; 390 u8 inbuf[4]; 391 u8 pd; 392 u8 ref; 393 int err; 394 395 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 396 if (indio_dev == NULL) 397 return -ENOMEM; 398 data = iio_priv(indio_dev); 399 i2c_set_clientdata(client, indio_dev); 400 data->client = client; 401 if (dev_fwnode(&client->dev)) 402 data->id = (uintptr_t)device_get_match_data(&client->dev); 403 else 404 data->id = id->driver_data; 405 pdata = dev_get_platdata(&client->dev); 406 407 if (!pdata) { 408 err = mcp4725_probe_dt(&client->dev, &pdata_dt); 409 if (err) { 410 dev_err(&client->dev, 411 "invalid platform or devicetree data"); 412 return err; 413 } 414 pdata = &pdata_dt; 415 } 416 417 if (data->id == MCP4725 && pdata->use_vref) { 418 dev_err(&client->dev, 419 "external reference is unavailable on MCP4725"); 420 return -EINVAL; 421 } 422 423 if (!pdata->use_vref && pdata->vref_buffered) { 424 dev_err(&client->dev, 425 "buffering is unavailable on the internal reference"); 426 return -EINVAL; 427 } 428 429 if (!pdata->use_vref) 430 data->ref_mode = MCP472X_REF_VDD; 431 else 432 data->ref_mode = pdata->vref_buffered ? 433 MCP472X_REF_VREF_BUFFERED : 434 MCP472X_REF_VREF_UNBUFFERED; 435 436 data->vdd_reg = devm_regulator_get(&client->dev, "vdd"); 437 if (IS_ERR(data->vdd_reg)) 438 return PTR_ERR(data->vdd_reg); 439 440 err = regulator_enable(data->vdd_reg); 441 if (err) 442 return err; 443 444 if (pdata->use_vref) { 445 data->vref_reg = devm_regulator_get(&client->dev, "vref"); 446 if (IS_ERR(data->vref_reg)) { 447 err = PTR_ERR(data->vref_reg); 448 goto err_disable_vdd_reg; 449 } 450 451 err = regulator_enable(data->vref_reg); 452 if (err) 453 goto err_disable_vdd_reg; 454 } 455 456 indio_dev->name = id->name; 457 indio_dev->info = &mcp4725_info; 458 indio_dev->channels = &mcp472x_channel[id->driver_data]; 459 indio_dev->num_channels = 1; 460 indio_dev->modes = INDIO_DIRECT_MODE; 461 462 /* read current DAC value and settings */ 463 err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4); 464 465 if (err < 0) { 466 dev_err(&client->dev, "failed to read DAC value"); 467 goto err_disable_vref_reg; 468 } 469 pd = (inbuf[0] >> 1) & 0x3; 470 data->powerdown = pd > 0; 471 data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */ 472 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); 473 if (data->id == MCP4726) 474 ref = (inbuf[3] >> 3) & 0x3; 475 476 if (data->id == MCP4726 && ref != data->ref_mode) { 477 dev_info(&client->dev, 478 "voltage reference mode differs (conf: %u, eeprom: %u), setting %u", 479 data->ref_mode, ref, data->ref_mode); 480 err = mcp4726_set_cfg(indio_dev); 481 if (err < 0) 482 goto err_disable_vref_reg; 483 } 484 485 err = iio_device_register(indio_dev); 486 if (err) 487 goto err_disable_vref_reg; 488 489 return 0; 490 491 err_disable_vref_reg: 492 if (data->vref_reg) 493 regulator_disable(data->vref_reg); 494 495 err_disable_vdd_reg: 496 regulator_disable(data->vdd_reg); 497 498 return err; 499 } 500 501 static void mcp4725_remove(struct i2c_client *client) 502 { 503 struct iio_dev *indio_dev = i2c_get_clientdata(client); 504 struct mcp4725_data *data = iio_priv(indio_dev); 505 506 iio_device_unregister(indio_dev); 507 508 if (data->vref_reg) 509 regulator_disable(data->vref_reg); 510 regulator_disable(data->vdd_reg); 511 } 512 513 static const struct i2c_device_id mcp4725_id[] = { 514 { "mcp4725", MCP4725 }, 515 { "mcp4726", MCP4726 }, 516 { } 517 }; 518 MODULE_DEVICE_TABLE(i2c, mcp4725_id); 519 520 static const struct of_device_id mcp4725_of_match[] = { 521 { 522 .compatible = "microchip,mcp4725", 523 .data = (void *)MCP4725 524 }, 525 { 526 .compatible = "microchip,mcp4726", 527 .data = (void *)MCP4726 528 }, 529 { } 530 }; 531 MODULE_DEVICE_TABLE(of, mcp4725_of_match); 532 533 static struct i2c_driver mcp4725_driver = { 534 .driver = { 535 .name = MCP4725_DRV_NAME, 536 .of_match_table = mcp4725_of_match, 537 .pm = pm_sleep_ptr(&mcp4725_pm_ops), 538 }, 539 .probe_new = mcp4725_probe, 540 .remove = mcp4725_remove, 541 .id_table = mcp4725_id, 542 }; 543 module_i2c_driver(mcp4725_driver); 544 545 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); 546 MODULE_DESCRIPTION("MCP4725/6 12-bit DAC"); 547 MODULE_LICENSE("GPL"); 548