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