1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2015 Prevas A/S 4 */ 5 6 #include <linux/device.h> 7 #include <linux/kernel.h> 8 #include <linux/slab.h> 9 #include <linux/sysfs.h> 10 #include <linux/spi/spi.h> 11 #include <linux/regulator/consumer.h> 12 #include <linux/err.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 16 #include <linux/iio/iio.h> 17 #include <linux/iio/buffer.h> 18 #include <linux/iio/trigger_consumer.h> 19 #include <linux/iio/triggered_buffer.h> 20 #include <linux/iio/sysfs.h> 21 22 #define ADS8688_CMD_REG(x) (x << 8) 23 #define ADS8688_CMD_REG_NOOP 0x00 24 #define ADS8688_CMD_REG_RST 0x85 25 #define ADS8688_CMD_REG_MAN_CH(chan) (0xC0 | (4 * chan)) 26 #define ADS8688_CMD_DONT_CARE_BITS 16 27 28 #define ADS8688_PROG_REG(x) (x << 9) 29 #define ADS8688_PROG_REG_RANGE_CH(chan) (0x05 + chan) 30 #define ADS8688_PROG_WR_BIT BIT(8) 31 #define ADS8688_PROG_DONT_CARE_BITS 8 32 33 #define ADS8688_REG_PLUSMINUS25VREF 0 34 #define ADS8688_REG_PLUSMINUS125VREF 1 35 #define ADS8688_REG_PLUSMINUS0625VREF 2 36 #define ADS8688_REG_PLUS25VREF 5 37 #define ADS8688_REG_PLUS125VREF 6 38 39 #define ADS8688_VREF_MV 4096 40 #define ADS8688_REALBITS 16 41 #define ADS8688_MAX_CHANNELS 8 42 43 /* 44 * enum ads8688_range - ADS8688 reference voltage range 45 * @ADS8688_PLUSMINUS25VREF: Device is configured for input range ±2.5 * VREF 46 * @ADS8688_PLUSMINUS125VREF: Device is configured for input range ±1.25 * VREF 47 * @ADS8688_PLUSMINUS0625VREF: Device is configured for input range ±0.625 * VREF 48 * @ADS8688_PLUS25VREF: Device is configured for input range 0 - 2.5 * VREF 49 * @ADS8688_PLUS125VREF: Device is configured for input range 0 - 1.25 * VREF 50 */ 51 enum ads8688_range { 52 ADS8688_PLUSMINUS25VREF, 53 ADS8688_PLUSMINUS125VREF, 54 ADS8688_PLUSMINUS0625VREF, 55 ADS8688_PLUS25VREF, 56 ADS8688_PLUS125VREF, 57 }; 58 59 struct ads8688_chip_info { 60 const struct iio_chan_spec *channels; 61 unsigned int num_channels; 62 }; 63 64 struct ads8688_state { 65 struct mutex lock; 66 const struct ads8688_chip_info *chip_info; 67 struct spi_device *spi; 68 struct regulator *reg; 69 unsigned int vref_mv; 70 enum ads8688_range range[8]; 71 union { 72 __be32 d32; 73 u8 d8[4]; 74 } data[2] ____cacheline_aligned; 75 }; 76 77 enum ads8688_id { 78 ID_ADS8684, 79 ID_ADS8688, 80 }; 81 82 struct ads8688_ranges { 83 enum ads8688_range range; 84 unsigned int scale; 85 int offset; 86 u8 reg; 87 }; 88 89 static const struct ads8688_ranges ads8688_range_def[5] = { 90 { 91 .range = ADS8688_PLUSMINUS25VREF, 92 .scale = 76295, 93 .offset = -(1 << (ADS8688_REALBITS - 1)), 94 .reg = ADS8688_REG_PLUSMINUS25VREF, 95 }, { 96 .range = ADS8688_PLUSMINUS125VREF, 97 .scale = 38148, 98 .offset = -(1 << (ADS8688_REALBITS - 1)), 99 .reg = ADS8688_REG_PLUSMINUS125VREF, 100 }, { 101 .range = ADS8688_PLUSMINUS0625VREF, 102 .scale = 19074, 103 .offset = -(1 << (ADS8688_REALBITS - 1)), 104 .reg = ADS8688_REG_PLUSMINUS0625VREF, 105 }, { 106 .range = ADS8688_PLUS25VREF, 107 .scale = 38148, 108 .offset = 0, 109 .reg = ADS8688_REG_PLUS25VREF, 110 }, { 111 .range = ADS8688_PLUS125VREF, 112 .scale = 19074, 113 .offset = 0, 114 .reg = ADS8688_REG_PLUS125VREF, 115 } 116 }; 117 118 static ssize_t ads8688_show_scales(struct device *dev, 119 struct device_attribute *attr, char *buf) 120 { 121 struct ads8688_state *st = iio_priv(dev_to_iio_dev(dev)); 122 123 return sprintf(buf, "0.%09u 0.%09u 0.%09u\n", 124 ads8688_range_def[0].scale * st->vref_mv, 125 ads8688_range_def[1].scale * st->vref_mv, 126 ads8688_range_def[2].scale * st->vref_mv); 127 } 128 129 static ssize_t ads8688_show_offsets(struct device *dev, 130 struct device_attribute *attr, char *buf) 131 { 132 return sprintf(buf, "%d %d\n", ads8688_range_def[0].offset, 133 ads8688_range_def[3].offset); 134 } 135 136 static IIO_DEVICE_ATTR(in_voltage_scale_available, S_IRUGO, 137 ads8688_show_scales, NULL, 0); 138 static IIO_DEVICE_ATTR(in_voltage_offset_available, S_IRUGO, 139 ads8688_show_offsets, NULL, 0); 140 141 static struct attribute *ads8688_attributes[] = { 142 &iio_dev_attr_in_voltage_scale_available.dev_attr.attr, 143 &iio_dev_attr_in_voltage_offset_available.dev_attr.attr, 144 NULL, 145 }; 146 147 static const struct attribute_group ads8688_attribute_group = { 148 .attrs = ads8688_attributes, 149 }; 150 151 #define ADS8688_CHAN(index) \ 152 { \ 153 .type = IIO_VOLTAGE, \ 154 .indexed = 1, \ 155 .channel = index, \ 156 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \ 157 | BIT(IIO_CHAN_INFO_SCALE) \ 158 | BIT(IIO_CHAN_INFO_OFFSET), \ 159 .scan_index = index, \ 160 .scan_type = { \ 161 .sign = 'u', \ 162 .realbits = 16, \ 163 .storagebits = 16, \ 164 .endianness = IIO_BE, \ 165 }, \ 166 } 167 168 static const struct iio_chan_spec ads8684_channels[] = { 169 ADS8688_CHAN(0), 170 ADS8688_CHAN(1), 171 ADS8688_CHAN(2), 172 ADS8688_CHAN(3), 173 }; 174 175 static const struct iio_chan_spec ads8688_channels[] = { 176 ADS8688_CHAN(0), 177 ADS8688_CHAN(1), 178 ADS8688_CHAN(2), 179 ADS8688_CHAN(3), 180 ADS8688_CHAN(4), 181 ADS8688_CHAN(5), 182 ADS8688_CHAN(6), 183 ADS8688_CHAN(7), 184 }; 185 186 static int ads8688_prog_write(struct iio_dev *indio_dev, unsigned int addr, 187 unsigned int val) 188 { 189 struct ads8688_state *st = iio_priv(indio_dev); 190 u32 tmp; 191 192 tmp = ADS8688_PROG_REG(addr) | ADS8688_PROG_WR_BIT | val; 193 tmp <<= ADS8688_PROG_DONT_CARE_BITS; 194 st->data[0].d32 = cpu_to_be32(tmp); 195 196 return spi_write(st->spi, &st->data[0].d8[1], 3); 197 } 198 199 static int ads8688_reset(struct iio_dev *indio_dev) 200 { 201 struct ads8688_state *st = iio_priv(indio_dev); 202 u32 tmp; 203 204 tmp = ADS8688_CMD_REG(ADS8688_CMD_REG_RST); 205 tmp <<= ADS8688_CMD_DONT_CARE_BITS; 206 st->data[0].d32 = cpu_to_be32(tmp); 207 208 return spi_write(st->spi, &st->data[0].d8[0], 4); 209 } 210 211 static int ads8688_read(struct iio_dev *indio_dev, unsigned int chan) 212 { 213 struct ads8688_state *st = iio_priv(indio_dev); 214 int ret; 215 u32 tmp; 216 struct spi_transfer t[] = { 217 { 218 .tx_buf = &st->data[0].d8[0], 219 .len = 4, 220 .cs_change = 1, 221 }, { 222 .tx_buf = &st->data[1].d8[0], 223 .rx_buf = &st->data[1].d8[0], 224 .len = 4, 225 }, 226 }; 227 228 tmp = ADS8688_CMD_REG(ADS8688_CMD_REG_MAN_CH(chan)); 229 tmp <<= ADS8688_CMD_DONT_CARE_BITS; 230 st->data[0].d32 = cpu_to_be32(tmp); 231 232 tmp = ADS8688_CMD_REG(ADS8688_CMD_REG_NOOP); 233 tmp <<= ADS8688_CMD_DONT_CARE_BITS; 234 st->data[1].d32 = cpu_to_be32(tmp); 235 236 ret = spi_sync_transfer(st->spi, t, ARRAY_SIZE(t)); 237 if (ret < 0) 238 return ret; 239 240 return be32_to_cpu(st->data[1].d32) & 0xffff; 241 } 242 243 static int ads8688_read_raw(struct iio_dev *indio_dev, 244 struct iio_chan_spec const *chan, 245 int *val, int *val2, long m) 246 { 247 int ret, offset; 248 unsigned long scale_mv; 249 250 struct ads8688_state *st = iio_priv(indio_dev); 251 252 mutex_lock(&st->lock); 253 switch (m) { 254 case IIO_CHAN_INFO_RAW: 255 ret = ads8688_read(indio_dev, chan->channel); 256 mutex_unlock(&st->lock); 257 if (ret < 0) 258 return ret; 259 *val = ret; 260 return IIO_VAL_INT; 261 case IIO_CHAN_INFO_SCALE: 262 scale_mv = st->vref_mv; 263 scale_mv *= ads8688_range_def[st->range[chan->channel]].scale; 264 *val = 0; 265 *val2 = scale_mv; 266 mutex_unlock(&st->lock); 267 return IIO_VAL_INT_PLUS_NANO; 268 case IIO_CHAN_INFO_OFFSET: 269 offset = ads8688_range_def[st->range[chan->channel]].offset; 270 *val = offset; 271 mutex_unlock(&st->lock); 272 return IIO_VAL_INT; 273 } 274 mutex_unlock(&st->lock); 275 276 return -EINVAL; 277 } 278 279 static int ads8688_write_reg_range(struct iio_dev *indio_dev, 280 struct iio_chan_spec const *chan, 281 enum ads8688_range range) 282 { 283 unsigned int tmp; 284 285 tmp = ADS8688_PROG_REG_RANGE_CH(chan->channel); 286 287 return ads8688_prog_write(indio_dev, tmp, range); 288 } 289 290 static int ads8688_write_raw(struct iio_dev *indio_dev, 291 struct iio_chan_spec const *chan, 292 int val, int val2, long mask) 293 { 294 struct ads8688_state *st = iio_priv(indio_dev); 295 unsigned int scale = 0; 296 int ret = -EINVAL, i, offset = 0; 297 298 mutex_lock(&st->lock); 299 switch (mask) { 300 case IIO_CHAN_INFO_SCALE: 301 /* If the offset is 0 the ±2.5 * VREF mode is not available */ 302 offset = ads8688_range_def[st->range[chan->channel]].offset; 303 if (offset == 0 && val2 == ads8688_range_def[0].scale * st->vref_mv) { 304 mutex_unlock(&st->lock); 305 return -EINVAL; 306 } 307 308 /* Lookup new mode */ 309 for (i = 0; i < ARRAY_SIZE(ads8688_range_def); i++) 310 if (val2 == ads8688_range_def[i].scale * st->vref_mv && 311 offset == ads8688_range_def[i].offset) { 312 ret = ads8688_write_reg_range(indio_dev, chan, 313 ads8688_range_def[i].reg); 314 break; 315 } 316 break; 317 case IIO_CHAN_INFO_OFFSET: 318 /* 319 * There are only two available offsets: 320 * 0 and -(1 << (ADS8688_REALBITS - 1)) 321 */ 322 if (!(ads8688_range_def[0].offset == val || 323 ads8688_range_def[3].offset == val)) { 324 mutex_unlock(&st->lock); 325 return -EINVAL; 326 } 327 328 /* 329 * If the device are in ±2.5 * VREF mode, it's not allowed to 330 * switch to a mode where the offset is 0 331 */ 332 if (val == 0 && 333 st->range[chan->channel] == ADS8688_PLUSMINUS25VREF) { 334 mutex_unlock(&st->lock); 335 return -EINVAL; 336 } 337 338 scale = ads8688_range_def[st->range[chan->channel]].scale; 339 340 /* Lookup new mode */ 341 for (i = 0; i < ARRAY_SIZE(ads8688_range_def); i++) 342 if (val == ads8688_range_def[i].offset && 343 scale == ads8688_range_def[i].scale) { 344 ret = ads8688_write_reg_range(indio_dev, chan, 345 ads8688_range_def[i].reg); 346 break; 347 } 348 break; 349 } 350 351 if (!ret) 352 st->range[chan->channel] = ads8688_range_def[i].range; 353 354 mutex_unlock(&st->lock); 355 356 return ret; 357 } 358 359 static int ads8688_write_raw_get_fmt(struct iio_dev *indio_dev, 360 struct iio_chan_spec const *chan, 361 long mask) 362 { 363 switch (mask) { 364 case IIO_CHAN_INFO_SCALE: 365 return IIO_VAL_INT_PLUS_NANO; 366 case IIO_CHAN_INFO_OFFSET: 367 return IIO_VAL_INT; 368 } 369 370 return -EINVAL; 371 } 372 373 static const struct iio_info ads8688_info = { 374 .read_raw = &ads8688_read_raw, 375 .write_raw = &ads8688_write_raw, 376 .write_raw_get_fmt = &ads8688_write_raw_get_fmt, 377 .attrs = &ads8688_attribute_group, 378 }; 379 380 static irqreturn_t ads8688_trigger_handler(int irq, void *p) 381 { 382 struct iio_poll_func *pf = p; 383 struct iio_dev *indio_dev = pf->indio_dev; 384 /* Ensure naturally aligned timestamp */ 385 u16 buffer[ADS8688_MAX_CHANNELS + sizeof(s64)/sizeof(u16)] __aligned(8); 386 int i, j = 0; 387 388 for (i = 0; i < indio_dev->masklength; i++) { 389 if (!test_bit(i, indio_dev->active_scan_mask)) 390 continue; 391 buffer[j] = ads8688_read(indio_dev, i); 392 j++; 393 } 394 395 iio_push_to_buffers_with_timestamp(indio_dev, buffer, 396 iio_get_time_ns(indio_dev)); 397 398 iio_trigger_notify_done(indio_dev->trig); 399 400 return IRQ_HANDLED; 401 } 402 403 static const struct ads8688_chip_info ads8688_chip_info_tbl[] = { 404 [ID_ADS8684] = { 405 .channels = ads8684_channels, 406 .num_channels = ARRAY_SIZE(ads8684_channels), 407 }, 408 [ID_ADS8688] = { 409 .channels = ads8688_channels, 410 .num_channels = ARRAY_SIZE(ads8688_channels), 411 }, 412 }; 413 414 static int ads8688_probe(struct spi_device *spi) 415 { 416 struct ads8688_state *st; 417 struct iio_dev *indio_dev; 418 int ret; 419 420 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 421 if (indio_dev == NULL) 422 return -ENOMEM; 423 424 st = iio_priv(indio_dev); 425 426 st->reg = devm_regulator_get_optional(&spi->dev, "vref"); 427 if (!IS_ERR(st->reg)) { 428 ret = regulator_enable(st->reg); 429 if (ret) 430 return ret; 431 432 ret = regulator_get_voltage(st->reg); 433 if (ret < 0) 434 goto err_regulator_disable; 435 436 st->vref_mv = ret / 1000; 437 } else { 438 /* Use internal reference */ 439 st->vref_mv = ADS8688_VREF_MV; 440 } 441 442 st->chip_info = &ads8688_chip_info_tbl[spi_get_device_id(spi)->driver_data]; 443 444 spi->mode = SPI_MODE_1; 445 446 spi_set_drvdata(spi, indio_dev); 447 448 st->spi = spi; 449 450 indio_dev->name = spi_get_device_id(spi)->name; 451 indio_dev->modes = INDIO_DIRECT_MODE; 452 indio_dev->channels = st->chip_info->channels; 453 indio_dev->num_channels = st->chip_info->num_channels; 454 indio_dev->info = &ads8688_info; 455 456 ads8688_reset(indio_dev); 457 458 mutex_init(&st->lock); 459 460 ret = iio_triggered_buffer_setup(indio_dev, NULL, ads8688_trigger_handler, NULL); 461 if (ret < 0) { 462 dev_err(&spi->dev, "iio triggered buffer setup failed\n"); 463 goto err_regulator_disable; 464 } 465 466 ret = iio_device_register(indio_dev); 467 if (ret) 468 goto err_buffer_cleanup; 469 470 return 0; 471 472 err_buffer_cleanup: 473 iio_triggered_buffer_cleanup(indio_dev); 474 475 err_regulator_disable: 476 if (!IS_ERR(st->reg)) 477 regulator_disable(st->reg); 478 479 return ret; 480 } 481 482 static void ads8688_remove(struct spi_device *spi) 483 { 484 struct iio_dev *indio_dev = spi_get_drvdata(spi); 485 struct ads8688_state *st = iio_priv(indio_dev); 486 487 iio_device_unregister(indio_dev); 488 iio_triggered_buffer_cleanup(indio_dev); 489 490 if (!IS_ERR(st->reg)) 491 regulator_disable(st->reg); 492 } 493 494 static const struct spi_device_id ads8688_id[] = { 495 {"ads8684", ID_ADS8684}, 496 {"ads8688", ID_ADS8688}, 497 {} 498 }; 499 MODULE_DEVICE_TABLE(spi, ads8688_id); 500 501 static const struct of_device_id ads8688_of_match[] = { 502 { .compatible = "ti,ads8684" }, 503 { .compatible = "ti,ads8688" }, 504 { } 505 }; 506 MODULE_DEVICE_TABLE(of, ads8688_of_match); 507 508 static struct spi_driver ads8688_driver = { 509 .driver = { 510 .name = "ads8688", 511 .of_match_table = ads8688_of_match, 512 }, 513 .probe = ads8688_probe, 514 .remove = ads8688_remove, 515 .id_table = ads8688_id, 516 }; 517 module_spi_driver(ads8688_driver); 518 519 MODULE_AUTHOR("Sean Nyekjaer <sean@geanix.dk>"); 520 MODULE_DESCRIPTION("Texas Instruments ADS8688 driver"); 521 MODULE_LICENSE("GPL v2"); 522