1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Industrial I/O driver for Microchip digital potentiometers 4 * 5 * Copyright (c) 2016 Slawomir Stepien 6 * Based on: Peter Rosin's code from mcp4531.c 7 * 8 * Datasheet: https://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf 9 * 10 * DEVID #Wipers #Positions Resistor Opts (kOhm) 11 * mcp4131 1 129 5, 10, 50, 100 12 * mcp4132 1 129 5, 10, 50, 100 13 * mcp4141 1 129 5, 10, 50, 100 14 * mcp4142 1 129 5, 10, 50, 100 15 * mcp4151 1 257 5, 10, 50, 100 16 * mcp4152 1 257 5, 10, 50, 100 17 * mcp4161 1 257 5, 10, 50, 100 18 * mcp4162 1 257 5, 10, 50, 100 19 * mcp4231 2 129 5, 10, 50, 100 20 * mcp4232 2 129 5, 10, 50, 100 21 * mcp4241 2 129 5, 10, 50, 100 22 * mcp4242 2 129 5, 10, 50, 100 23 * mcp4251 2 257 5, 10, 50, 100 24 * mcp4252 2 257 5, 10, 50, 100 25 * mcp4261 2 257 5, 10, 50, 100 26 * mcp4262 2 257 5, 10, 50, 100 27 */ 28 29 /* 30 * TODO: 31 * 1. Write wiper setting to EEPROM for EEPROM capable models. 32 */ 33 34 #include <linux/cache.h> 35 #include <linux/err.h> 36 #include <linux/export.h> 37 #include <linux/iio/iio.h> 38 #include <linux/iio/types.h> 39 #include <linux/module.h> 40 #include <linux/mod_devicetable.h> 41 #include <linux/mutex.h> 42 #include <linux/property.h> 43 #include <linux/spi/spi.h> 44 45 #define MCP4131_WRITE (0x00 << 2) 46 #define MCP4131_READ (0x03 << 2) 47 48 #define MCP4131_WIPER_SHIFT 4 49 #define MCP4131_CMDERR(r) ((r[0]) & 0x02) 50 #define MCP4131_RAW(r) ((r[0]) == 0xff ? 0x100 : (r[1])) 51 52 struct mcp4131_cfg { 53 int wipers; 54 int max_pos; 55 int kohms; 56 }; 57 58 enum mcp4131_type { 59 MCP413x_502 = 0, 60 MCP413x_103, 61 MCP413x_503, 62 MCP413x_104, 63 MCP414x_502, 64 MCP414x_103, 65 MCP414x_503, 66 MCP414x_104, 67 MCP415x_502, 68 MCP415x_103, 69 MCP415x_503, 70 MCP415x_104, 71 MCP416x_502, 72 MCP416x_103, 73 MCP416x_503, 74 MCP416x_104, 75 MCP423x_502, 76 MCP423x_103, 77 MCP423x_503, 78 MCP423x_104, 79 MCP424x_502, 80 MCP424x_103, 81 MCP424x_503, 82 MCP424x_104, 83 MCP425x_502, 84 MCP425x_103, 85 MCP425x_503, 86 MCP425x_104, 87 MCP426x_502, 88 MCP426x_103, 89 MCP426x_503, 90 MCP426x_104, 91 }; 92 93 static const struct mcp4131_cfg mcp4131_cfg[] = { 94 [MCP413x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, }, 95 [MCP413x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, }, 96 [MCP413x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, }, 97 [MCP413x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, }, 98 [MCP414x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, }, 99 [MCP414x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, }, 100 [MCP414x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, }, 101 [MCP414x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, }, 102 [MCP415x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, }, 103 [MCP415x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, }, 104 [MCP415x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, }, 105 [MCP415x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, }, 106 [MCP416x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, }, 107 [MCP416x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, }, 108 [MCP416x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, }, 109 [MCP416x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, }, 110 [MCP423x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, }, 111 [MCP423x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, }, 112 [MCP423x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, }, 113 [MCP423x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, }, 114 [MCP424x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, }, 115 [MCP424x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, }, 116 [MCP424x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, }, 117 [MCP424x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, }, 118 [MCP425x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, }, 119 [MCP425x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, }, 120 [MCP425x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, }, 121 [MCP425x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, }, 122 [MCP426x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, }, 123 [MCP426x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, }, 124 [MCP426x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, }, 125 [MCP426x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, }, 126 }; 127 128 struct mcp4131_data { 129 struct spi_device *spi; 130 const struct mcp4131_cfg *cfg; 131 struct mutex lock; 132 u8 buf[2] ____cacheline_aligned; 133 }; 134 135 #define MCP4131_CHANNEL(ch) { \ 136 .type = IIO_RESISTANCE, \ 137 .indexed = 1, \ 138 .output = 1, \ 139 .channel = (ch), \ 140 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 141 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 142 } 143 144 static const struct iio_chan_spec mcp4131_channels[] = { 145 MCP4131_CHANNEL(0), 146 MCP4131_CHANNEL(1), 147 }; 148 149 static int mcp4131_read(struct spi_device *spi, void *buf, size_t len) 150 { 151 struct spi_transfer t = { 152 .tx_buf = buf, /* We need to send addr, cmd and 12 bits */ 153 .rx_buf = buf, 154 .len = len, 155 }; 156 struct spi_message m; 157 158 spi_message_init(&m); 159 spi_message_add_tail(&t, &m); 160 161 return spi_sync(spi, &m); 162 } 163 164 static int mcp4131_read_raw(struct iio_dev *indio_dev, 165 struct iio_chan_spec const *chan, 166 int *val, int *val2, long mask) 167 { 168 int err; 169 struct mcp4131_data *data = iio_priv(indio_dev); 170 int address = chan->channel; 171 172 switch (mask) { 173 case IIO_CHAN_INFO_RAW: 174 mutex_lock(&data->lock); 175 176 data->buf[0] = (address << MCP4131_WIPER_SHIFT) | MCP4131_READ; 177 data->buf[1] = 0; 178 179 err = mcp4131_read(data->spi, data->buf, 2); 180 if (err) { 181 mutex_unlock(&data->lock); 182 return err; 183 } 184 185 /* Error, bad address/command combination */ 186 if (!MCP4131_CMDERR(data->buf)) { 187 mutex_unlock(&data->lock); 188 return -EIO; 189 } 190 191 *val = MCP4131_RAW(data->buf); 192 mutex_unlock(&data->lock); 193 194 return IIO_VAL_INT; 195 196 case IIO_CHAN_INFO_SCALE: 197 *val = 1000 * data->cfg->kohms; 198 *val2 = data->cfg->max_pos; 199 return IIO_VAL_FRACTIONAL; 200 } 201 202 return -EINVAL; 203 } 204 205 static int mcp4131_write_raw(struct iio_dev *indio_dev, 206 struct iio_chan_spec const *chan, 207 int val, int val2, long mask) 208 { 209 int err; 210 struct mcp4131_data *data = iio_priv(indio_dev); 211 int address = chan->channel << MCP4131_WIPER_SHIFT; 212 213 switch (mask) { 214 case IIO_CHAN_INFO_RAW: 215 if (val > data->cfg->max_pos || val < 0) 216 return -EINVAL; 217 break; 218 219 default: 220 return -EINVAL; 221 } 222 223 mutex_lock(&data->lock); 224 225 data->buf[0] = address << MCP4131_WIPER_SHIFT; 226 data->buf[0] |= MCP4131_WRITE | (val >> 8); 227 data->buf[1] = val & 0xFF; /* 8 bits here */ 228 229 err = spi_write(data->spi, data->buf, 2); 230 mutex_unlock(&data->lock); 231 232 return err; 233 } 234 235 static const struct iio_info mcp4131_info = { 236 .read_raw = mcp4131_read_raw, 237 .write_raw = mcp4131_write_raw, 238 }; 239 240 static int mcp4131_probe(struct spi_device *spi) 241 { 242 int err; 243 struct device *dev = &spi->dev; 244 unsigned long devid; 245 struct mcp4131_data *data; 246 struct iio_dev *indio_dev; 247 248 indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); 249 if (!indio_dev) 250 return -ENOMEM; 251 252 data = iio_priv(indio_dev); 253 spi_set_drvdata(spi, indio_dev); 254 data->spi = spi; 255 data->cfg = device_get_match_data(&spi->dev); 256 if (!data->cfg) { 257 devid = spi_get_device_id(spi)->driver_data; 258 data->cfg = &mcp4131_cfg[devid]; 259 } 260 261 mutex_init(&data->lock); 262 263 indio_dev->info = &mcp4131_info; 264 indio_dev->channels = mcp4131_channels; 265 indio_dev->num_channels = data->cfg->wipers; 266 indio_dev->name = spi_get_device_id(spi)->name; 267 268 err = devm_iio_device_register(dev, indio_dev); 269 if (err) { 270 dev_info(&spi->dev, "Unable to register %s\n", indio_dev->name); 271 return err; 272 } 273 274 return 0; 275 } 276 277 static const struct of_device_id mcp4131_dt_ids[] = { 278 { .compatible = "microchip,mcp4131-502", 279 .data = &mcp4131_cfg[MCP413x_502] }, 280 { .compatible = "microchip,mcp4131-103", 281 .data = &mcp4131_cfg[MCP413x_103] }, 282 { .compatible = "microchip,mcp4131-503", 283 .data = &mcp4131_cfg[MCP413x_503] }, 284 { .compatible = "microchip,mcp4131-104", 285 .data = &mcp4131_cfg[MCP413x_104] }, 286 { .compatible = "microchip,mcp4132-502", 287 .data = &mcp4131_cfg[MCP413x_502] }, 288 { .compatible = "microchip,mcp4132-103", 289 .data = &mcp4131_cfg[MCP413x_103] }, 290 { .compatible = "microchip,mcp4132-503", 291 .data = &mcp4131_cfg[MCP413x_503] }, 292 { .compatible = "microchip,mcp4132-104", 293 .data = &mcp4131_cfg[MCP413x_104] }, 294 { .compatible = "microchip,mcp4141-502", 295 .data = &mcp4131_cfg[MCP414x_502] }, 296 { .compatible = "microchip,mcp4141-103", 297 .data = &mcp4131_cfg[MCP414x_103] }, 298 { .compatible = "microchip,mcp4141-503", 299 .data = &mcp4131_cfg[MCP414x_503] }, 300 { .compatible = "microchip,mcp4141-104", 301 .data = &mcp4131_cfg[MCP414x_104] }, 302 { .compatible = "microchip,mcp4142-502", 303 .data = &mcp4131_cfg[MCP414x_502] }, 304 { .compatible = "microchip,mcp4142-103", 305 .data = &mcp4131_cfg[MCP414x_103] }, 306 { .compatible = "microchip,mcp4142-503", 307 .data = &mcp4131_cfg[MCP414x_503] }, 308 { .compatible = "microchip,mcp4142-104", 309 .data = &mcp4131_cfg[MCP414x_104] }, 310 { .compatible = "microchip,mcp4151-502", 311 .data = &mcp4131_cfg[MCP415x_502] }, 312 { .compatible = "microchip,mcp4151-103", 313 .data = &mcp4131_cfg[MCP415x_103] }, 314 { .compatible = "microchip,mcp4151-503", 315 .data = &mcp4131_cfg[MCP415x_503] }, 316 { .compatible = "microchip,mcp4151-104", 317 .data = &mcp4131_cfg[MCP415x_104] }, 318 { .compatible = "microchip,mcp4152-502", 319 .data = &mcp4131_cfg[MCP415x_502] }, 320 { .compatible = "microchip,mcp4152-103", 321 .data = &mcp4131_cfg[MCP415x_103] }, 322 { .compatible = "microchip,mcp4152-503", 323 .data = &mcp4131_cfg[MCP415x_503] }, 324 { .compatible = "microchip,mcp4152-104", 325 .data = &mcp4131_cfg[MCP415x_104] }, 326 { .compatible = "microchip,mcp4161-502", 327 .data = &mcp4131_cfg[MCP416x_502] }, 328 { .compatible = "microchip,mcp4161-103", 329 .data = &mcp4131_cfg[MCP416x_103] }, 330 { .compatible = "microchip,mcp4161-503", 331 .data = &mcp4131_cfg[MCP416x_503] }, 332 { .compatible = "microchip,mcp4161-104", 333 .data = &mcp4131_cfg[MCP416x_104] }, 334 { .compatible = "microchip,mcp4162-502", 335 .data = &mcp4131_cfg[MCP416x_502] }, 336 { .compatible = "microchip,mcp4162-103", 337 .data = &mcp4131_cfg[MCP416x_103] }, 338 { .compatible = "microchip,mcp4162-503", 339 .data = &mcp4131_cfg[MCP416x_503] }, 340 { .compatible = "microchip,mcp4162-104", 341 .data = &mcp4131_cfg[MCP416x_104] }, 342 { .compatible = "microchip,mcp4231-502", 343 .data = &mcp4131_cfg[MCP423x_502] }, 344 { .compatible = "microchip,mcp4231-103", 345 .data = &mcp4131_cfg[MCP423x_103] }, 346 { .compatible = "microchip,mcp4231-503", 347 .data = &mcp4131_cfg[MCP423x_503] }, 348 { .compatible = "microchip,mcp4231-104", 349 .data = &mcp4131_cfg[MCP423x_104] }, 350 { .compatible = "microchip,mcp4232-502", 351 .data = &mcp4131_cfg[MCP423x_502] }, 352 { .compatible = "microchip,mcp4232-103", 353 .data = &mcp4131_cfg[MCP423x_103] }, 354 { .compatible = "microchip,mcp4232-503", 355 .data = &mcp4131_cfg[MCP423x_503] }, 356 { .compatible = "microchip,mcp4232-104", 357 .data = &mcp4131_cfg[MCP423x_104] }, 358 { .compatible = "microchip,mcp4241-502", 359 .data = &mcp4131_cfg[MCP424x_502] }, 360 { .compatible = "microchip,mcp4241-103", 361 .data = &mcp4131_cfg[MCP424x_103] }, 362 { .compatible = "microchip,mcp4241-503", 363 .data = &mcp4131_cfg[MCP424x_503] }, 364 { .compatible = "microchip,mcp4241-104", 365 .data = &mcp4131_cfg[MCP424x_104] }, 366 { .compatible = "microchip,mcp4242-502", 367 .data = &mcp4131_cfg[MCP424x_502] }, 368 { .compatible = "microchip,mcp4242-103", 369 .data = &mcp4131_cfg[MCP424x_103] }, 370 { .compatible = "microchip,mcp4242-503", 371 .data = &mcp4131_cfg[MCP424x_503] }, 372 { .compatible = "microchip,mcp4242-104", 373 .data = &mcp4131_cfg[MCP424x_104] }, 374 { .compatible = "microchip,mcp4251-502", 375 .data = &mcp4131_cfg[MCP425x_502] }, 376 { .compatible = "microchip,mcp4251-103", 377 .data = &mcp4131_cfg[MCP425x_103] }, 378 { .compatible = "microchip,mcp4251-503", 379 .data = &mcp4131_cfg[MCP425x_503] }, 380 { .compatible = "microchip,mcp4251-104", 381 .data = &mcp4131_cfg[MCP425x_104] }, 382 { .compatible = "microchip,mcp4252-502", 383 .data = &mcp4131_cfg[MCP425x_502] }, 384 { .compatible = "microchip,mcp4252-103", 385 .data = &mcp4131_cfg[MCP425x_103] }, 386 { .compatible = "microchip,mcp4252-503", 387 .data = &mcp4131_cfg[MCP425x_503] }, 388 { .compatible = "microchip,mcp4252-104", 389 .data = &mcp4131_cfg[MCP425x_104] }, 390 { .compatible = "microchip,mcp4261-502", 391 .data = &mcp4131_cfg[MCP426x_502] }, 392 { .compatible = "microchip,mcp4261-103", 393 .data = &mcp4131_cfg[MCP426x_103] }, 394 { .compatible = "microchip,mcp4261-503", 395 .data = &mcp4131_cfg[MCP426x_503] }, 396 { .compatible = "microchip,mcp4261-104", 397 .data = &mcp4131_cfg[MCP426x_104] }, 398 { .compatible = "microchip,mcp4262-502", 399 .data = &mcp4131_cfg[MCP426x_502] }, 400 { .compatible = "microchip,mcp4262-103", 401 .data = &mcp4131_cfg[MCP426x_103] }, 402 { .compatible = "microchip,mcp4262-503", 403 .data = &mcp4131_cfg[MCP426x_503] }, 404 { .compatible = "microchip,mcp4262-104", 405 .data = &mcp4131_cfg[MCP426x_104] }, 406 {} 407 }; 408 MODULE_DEVICE_TABLE(of, mcp4131_dt_ids); 409 410 static const struct spi_device_id mcp4131_id[] = { 411 { "mcp4131-502", MCP413x_502 }, 412 { "mcp4131-103", MCP413x_103 }, 413 { "mcp4131-503", MCP413x_503 }, 414 { "mcp4131-104", MCP413x_104 }, 415 { "mcp4132-502", MCP413x_502 }, 416 { "mcp4132-103", MCP413x_103 }, 417 { "mcp4132-503", MCP413x_503 }, 418 { "mcp4132-104", MCP413x_104 }, 419 { "mcp4141-502", MCP414x_502 }, 420 { "mcp4141-103", MCP414x_103 }, 421 { "mcp4141-503", MCP414x_503 }, 422 { "mcp4141-104", MCP414x_104 }, 423 { "mcp4142-502", MCP414x_502 }, 424 { "mcp4142-103", MCP414x_103 }, 425 { "mcp4142-503", MCP414x_503 }, 426 { "mcp4142-104", MCP414x_104 }, 427 { "mcp4151-502", MCP415x_502 }, 428 { "mcp4151-103", MCP415x_103 }, 429 { "mcp4151-503", MCP415x_503 }, 430 { "mcp4151-104", MCP415x_104 }, 431 { "mcp4152-502", MCP415x_502 }, 432 { "mcp4152-103", MCP415x_103 }, 433 { "mcp4152-503", MCP415x_503 }, 434 { "mcp4152-104", MCP415x_104 }, 435 { "mcp4161-502", MCP416x_502 }, 436 { "mcp4161-103", MCP416x_103 }, 437 { "mcp4161-503", MCP416x_503 }, 438 { "mcp4161-104", MCP416x_104 }, 439 { "mcp4162-502", MCP416x_502 }, 440 { "mcp4162-103", MCP416x_103 }, 441 { "mcp4162-503", MCP416x_503 }, 442 { "mcp4162-104", MCP416x_104 }, 443 { "mcp4231-502", MCP423x_502 }, 444 { "mcp4231-103", MCP423x_103 }, 445 { "mcp4231-503", MCP423x_503 }, 446 { "mcp4231-104", MCP423x_104 }, 447 { "mcp4232-502", MCP423x_502 }, 448 { "mcp4232-103", MCP423x_103 }, 449 { "mcp4232-503", MCP423x_503 }, 450 { "mcp4232-104", MCP423x_104 }, 451 { "mcp4241-502", MCP424x_502 }, 452 { "mcp4241-103", MCP424x_103 }, 453 { "mcp4241-503", MCP424x_503 }, 454 { "mcp4241-104", MCP424x_104 }, 455 { "mcp4242-502", MCP424x_502 }, 456 { "mcp4242-103", MCP424x_103 }, 457 { "mcp4242-503", MCP424x_503 }, 458 { "mcp4242-104", MCP424x_104 }, 459 { "mcp4251-502", MCP425x_502 }, 460 { "mcp4251-103", MCP425x_103 }, 461 { "mcp4251-503", MCP425x_503 }, 462 { "mcp4251-104", MCP425x_104 }, 463 { "mcp4252-502", MCP425x_502 }, 464 { "mcp4252-103", MCP425x_103 }, 465 { "mcp4252-503", MCP425x_503 }, 466 { "mcp4252-104", MCP425x_104 }, 467 { "mcp4261-502", MCP426x_502 }, 468 { "mcp4261-103", MCP426x_103 }, 469 { "mcp4261-503", MCP426x_503 }, 470 { "mcp4261-104", MCP426x_104 }, 471 { "mcp4262-502", MCP426x_502 }, 472 { "mcp4262-103", MCP426x_103 }, 473 { "mcp4262-503", MCP426x_503 }, 474 { "mcp4262-104", MCP426x_104 }, 475 {} 476 }; 477 MODULE_DEVICE_TABLE(spi, mcp4131_id); 478 479 static struct spi_driver mcp4131_driver = { 480 .driver = { 481 .name = "mcp4131", 482 .of_match_table = mcp4131_dt_ids, 483 }, 484 .probe = mcp4131_probe, 485 .id_table = mcp4131_id, 486 }; 487 488 module_spi_driver(mcp4131_driver); 489 490 MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>"); 491 MODULE_DESCRIPTION("MCP4131 digital potentiometer"); 492 MODULE_LICENSE("GPL v2"); 493