1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AD7266/65 SPI ADC driver 4 * 5 * Copyright 2012 Analog Devices Inc. 6 */ 7 8 #include <linux/device.h> 9 #include <linux/kernel.h> 10 #include <linux/slab.h> 11 #include <linux/spi/spi.h> 12 #include <linux/regulator/consumer.h> 13 #include <linux/err.h> 14 #include <linux/gpio/consumer.h> 15 #include <linux/module.h> 16 17 #include <linux/interrupt.h> 18 19 #include <linux/iio/iio.h> 20 #include <linux/iio/buffer.h> 21 #include <linux/iio/trigger_consumer.h> 22 #include <linux/iio/triggered_buffer.h> 23 24 #include <linux/platform_data/ad7266.h> 25 26 struct ad7266_state { 27 struct spi_device *spi; 28 struct regulator *reg; 29 unsigned long vref_mv; 30 31 struct spi_transfer single_xfer[3]; 32 struct spi_message single_msg; 33 34 enum ad7266_range range; 35 enum ad7266_mode mode; 36 bool fixed_addr; 37 struct gpio_desc *gpios[3]; 38 39 /* 40 * DMA (thus cache coherency maintenance) requires the 41 * transfer buffers to live in their own cache lines. 42 * The buffer needs to be large enough to hold two samples (4 bytes) and 43 * the naturally aligned timestamp (8 bytes). 44 */ 45 struct { 46 __be16 sample[2]; 47 s64 timestamp; 48 } data ____cacheline_aligned; 49 }; 50 51 static int ad7266_wakeup(struct ad7266_state *st) 52 { 53 /* Any read with >= 2 bytes will wake the device */ 54 return spi_read(st->spi, &st->data.sample[0], 2); 55 } 56 57 static int ad7266_powerdown(struct ad7266_state *st) 58 { 59 /* Any read with < 2 bytes will powerdown the device */ 60 return spi_read(st->spi, &st->data.sample[0], 1); 61 } 62 63 static int ad7266_preenable(struct iio_dev *indio_dev) 64 { 65 struct ad7266_state *st = iio_priv(indio_dev); 66 return ad7266_wakeup(st); 67 } 68 69 static int ad7266_postdisable(struct iio_dev *indio_dev) 70 { 71 struct ad7266_state *st = iio_priv(indio_dev); 72 return ad7266_powerdown(st); 73 } 74 75 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = { 76 .preenable = &ad7266_preenable, 77 .postdisable = &ad7266_postdisable, 78 }; 79 80 static irqreturn_t ad7266_trigger_handler(int irq, void *p) 81 { 82 struct iio_poll_func *pf = p; 83 struct iio_dev *indio_dev = pf->indio_dev; 84 struct ad7266_state *st = iio_priv(indio_dev); 85 int ret; 86 87 ret = spi_read(st->spi, st->data.sample, 4); 88 if (ret == 0) { 89 iio_push_to_buffers_with_timestamp(indio_dev, &st->data, 90 pf->timestamp); 91 } 92 93 iio_trigger_notify_done(indio_dev->trig); 94 95 return IRQ_HANDLED; 96 } 97 98 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr) 99 { 100 unsigned int i; 101 102 if (st->fixed_addr) 103 return; 104 105 switch (st->mode) { 106 case AD7266_MODE_SINGLE_ENDED: 107 nr >>= 1; 108 break; 109 case AD7266_MODE_PSEUDO_DIFF: 110 nr |= 1; 111 break; 112 case AD7266_MODE_DIFF: 113 nr &= ~1; 114 break; 115 } 116 117 for (i = 0; i < 3; ++i) 118 gpiod_set_value(st->gpios[i], (bool)(nr & BIT(i))); 119 } 120 121 static int ad7266_update_scan_mode(struct iio_dev *indio_dev, 122 const unsigned long *scan_mask) 123 { 124 struct ad7266_state *st = iio_priv(indio_dev); 125 unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength); 126 127 ad7266_select_input(st, nr); 128 129 return 0; 130 } 131 132 static int ad7266_read_single(struct ad7266_state *st, int *val, 133 unsigned int address) 134 { 135 int ret; 136 137 ad7266_select_input(st, address); 138 139 ret = spi_sync(st->spi, &st->single_msg); 140 *val = be16_to_cpu(st->data.sample[address % 2]); 141 142 return ret; 143 } 144 145 static int ad7266_read_raw(struct iio_dev *indio_dev, 146 struct iio_chan_spec const *chan, int *val, int *val2, long m) 147 { 148 struct ad7266_state *st = iio_priv(indio_dev); 149 unsigned long scale_mv; 150 int ret; 151 152 switch (m) { 153 case IIO_CHAN_INFO_RAW: 154 ret = iio_device_claim_direct_mode(indio_dev); 155 if (ret) 156 return ret; 157 ret = ad7266_read_single(st, val, chan->address); 158 iio_device_release_direct_mode(indio_dev); 159 160 *val = (*val >> 2) & 0xfff; 161 if (chan->scan_type.sign == 's') 162 *val = sign_extend32(*val, 163 chan->scan_type.realbits - 1); 164 165 return IIO_VAL_INT; 166 case IIO_CHAN_INFO_SCALE: 167 scale_mv = st->vref_mv; 168 if (st->mode == AD7266_MODE_DIFF) 169 scale_mv *= 2; 170 if (st->range == AD7266_RANGE_2VREF) 171 scale_mv *= 2; 172 173 *val = scale_mv; 174 *val2 = chan->scan_type.realbits; 175 return IIO_VAL_FRACTIONAL_LOG2; 176 case IIO_CHAN_INFO_OFFSET: 177 if (st->range == AD7266_RANGE_2VREF && 178 st->mode != AD7266_MODE_DIFF) 179 *val = 2048; 180 else 181 *val = 0; 182 return IIO_VAL_INT; 183 } 184 return -EINVAL; 185 } 186 187 #define AD7266_CHAN(_chan, _sign) { \ 188 .type = IIO_VOLTAGE, \ 189 .indexed = 1, \ 190 .channel = (_chan), \ 191 .address = (_chan), \ 192 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 193 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 194 | BIT(IIO_CHAN_INFO_OFFSET), \ 195 .scan_index = (_chan), \ 196 .scan_type = { \ 197 .sign = (_sign), \ 198 .realbits = 12, \ 199 .storagebits = 16, \ 200 .shift = 2, \ 201 .endianness = IIO_BE, \ 202 }, \ 203 } 204 205 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \ 206 const struct iio_chan_spec ad7266_channels_##_name[] = { \ 207 AD7266_CHAN(0, (_sign)), \ 208 AD7266_CHAN(1, (_sign)), \ 209 AD7266_CHAN(2, (_sign)), \ 210 AD7266_CHAN(3, (_sign)), \ 211 AD7266_CHAN(4, (_sign)), \ 212 AD7266_CHAN(5, (_sign)), \ 213 AD7266_CHAN(6, (_sign)), \ 214 AD7266_CHAN(7, (_sign)), \ 215 AD7266_CHAN(8, (_sign)), \ 216 AD7266_CHAN(9, (_sign)), \ 217 AD7266_CHAN(10, (_sign)), \ 218 AD7266_CHAN(11, (_sign)), \ 219 IIO_CHAN_SOFT_TIMESTAMP(13), \ 220 } 221 222 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \ 223 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \ 224 AD7266_CHAN(0, (_sign)), \ 225 AD7266_CHAN(1, (_sign)), \ 226 IIO_CHAN_SOFT_TIMESTAMP(2), \ 227 } 228 229 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u'); 230 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's'); 231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u'); 232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's'); 233 234 #define AD7266_CHAN_DIFF(_chan, _sign) { \ 235 .type = IIO_VOLTAGE, \ 236 .indexed = 1, \ 237 .channel = (_chan) * 2, \ 238 .channel2 = (_chan) * 2 + 1, \ 239 .address = (_chan), \ 240 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 241 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 242 | BIT(IIO_CHAN_INFO_OFFSET), \ 243 .scan_index = (_chan), \ 244 .scan_type = { \ 245 .sign = _sign, \ 246 .realbits = 12, \ 247 .storagebits = 16, \ 248 .shift = 2, \ 249 .endianness = IIO_BE, \ 250 }, \ 251 .differential = 1, \ 252 } 253 254 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \ 255 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \ 256 AD7266_CHAN_DIFF(0, (_sign)), \ 257 AD7266_CHAN_DIFF(1, (_sign)), \ 258 AD7266_CHAN_DIFF(2, (_sign)), \ 259 AD7266_CHAN_DIFF(3, (_sign)), \ 260 AD7266_CHAN_DIFF(4, (_sign)), \ 261 AD7266_CHAN_DIFF(5, (_sign)), \ 262 IIO_CHAN_SOFT_TIMESTAMP(6), \ 263 } 264 265 static AD7266_DECLARE_DIFF_CHANNELS(s, 's'); 266 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u'); 267 268 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \ 269 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \ 270 AD7266_CHAN_DIFF(0, (_sign)), \ 271 AD7266_CHAN_DIFF(1, (_sign)), \ 272 IIO_CHAN_SOFT_TIMESTAMP(2), \ 273 } 274 275 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's'); 276 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u'); 277 278 static const struct iio_info ad7266_info = { 279 .read_raw = &ad7266_read_raw, 280 .update_scan_mode = &ad7266_update_scan_mode, 281 }; 282 283 static const unsigned long ad7266_available_scan_masks[] = { 284 0x003, 285 0x00c, 286 0x030, 287 0x0c0, 288 0x300, 289 0xc00, 290 0x000, 291 }; 292 293 static const unsigned long ad7266_available_scan_masks_diff[] = { 294 0x003, 295 0x00c, 296 0x030, 297 0x000, 298 }; 299 300 static const unsigned long ad7266_available_scan_masks_fixed[] = { 301 0x003, 302 0x000, 303 }; 304 305 struct ad7266_chan_info { 306 const struct iio_chan_spec *channels; 307 unsigned int num_channels; 308 const unsigned long *scan_masks; 309 }; 310 311 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \ 312 (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0)) 313 314 static const struct ad7266_chan_info ad7266_chan_infos[] = { 315 [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = { 316 .channels = ad7266_channels_u, 317 .num_channels = ARRAY_SIZE(ad7266_channels_u), 318 .scan_masks = ad7266_available_scan_masks, 319 }, 320 [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = { 321 .channels = ad7266_channels_u_fixed, 322 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed), 323 .scan_masks = ad7266_available_scan_masks_fixed, 324 }, 325 [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = { 326 .channels = ad7266_channels_s, 327 .num_channels = ARRAY_SIZE(ad7266_channels_s), 328 .scan_masks = ad7266_available_scan_masks, 329 }, 330 [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = { 331 .channels = ad7266_channels_s_fixed, 332 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed), 333 .scan_masks = ad7266_available_scan_masks_fixed, 334 }, 335 [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = { 336 .channels = ad7266_channels_diff_u, 337 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u), 338 .scan_masks = ad7266_available_scan_masks_diff, 339 }, 340 [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = { 341 .channels = ad7266_channels_diff_fixed_u, 342 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u), 343 .scan_masks = ad7266_available_scan_masks_fixed, 344 }, 345 [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = { 346 .channels = ad7266_channels_diff_s, 347 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s), 348 .scan_masks = ad7266_available_scan_masks_diff, 349 }, 350 [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = { 351 .channels = ad7266_channels_diff_fixed_s, 352 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s), 353 .scan_masks = ad7266_available_scan_masks_fixed, 354 }, 355 }; 356 357 static void ad7266_init_channels(struct iio_dev *indio_dev) 358 { 359 struct ad7266_state *st = iio_priv(indio_dev); 360 bool is_differential, is_signed; 361 const struct ad7266_chan_info *chan_info; 362 int i; 363 364 is_differential = st->mode != AD7266_MODE_SINGLE_ENDED; 365 is_signed = (st->range == AD7266_RANGE_2VREF) | 366 (st->mode == AD7266_MODE_DIFF); 367 368 i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr); 369 chan_info = &ad7266_chan_infos[i]; 370 371 indio_dev->channels = chan_info->channels; 372 indio_dev->num_channels = chan_info->num_channels; 373 indio_dev->available_scan_masks = chan_info->scan_masks; 374 indio_dev->masklength = chan_info->num_channels - 1; 375 } 376 377 static const char * const ad7266_gpio_labels[] = { 378 "ad0", "ad1", "ad2", 379 }; 380 381 static int ad7266_probe(struct spi_device *spi) 382 { 383 struct ad7266_platform_data *pdata = spi->dev.platform_data; 384 struct iio_dev *indio_dev; 385 struct ad7266_state *st; 386 unsigned int i; 387 int ret; 388 389 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 390 if (indio_dev == NULL) 391 return -ENOMEM; 392 393 st = iio_priv(indio_dev); 394 395 st->reg = devm_regulator_get_optional(&spi->dev, "vref"); 396 if (!IS_ERR(st->reg)) { 397 ret = regulator_enable(st->reg); 398 if (ret) 399 return ret; 400 401 ret = regulator_get_voltage(st->reg); 402 if (ret < 0) 403 goto error_disable_reg; 404 405 st->vref_mv = ret / 1000; 406 } else { 407 /* Any other error indicates that the regulator does exist */ 408 if (PTR_ERR(st->reg) != -ENODEV) 409 return PTR_ERR(st->reg); 410 /* Use internal reference */ 411 st->vref_mv = 2500; 412 } 413 414 if (pdata) { 415 st->fixed_addr = pdata->fixed_addr; 416 st->mode = pdata->mode; 417 st->range = pdata->range; 418 419 if (!st->fixed_addr) { 420 for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) { 421 st->gpios[i] = devm_gpiod_get(&spi->dev, 422 ad7266_gpio_labels[i], 423 GPIOD_OUT_LOW); 424 if (IS_ERR(st->gpios[i])) { 425 ret = PTR_ERR(st->gpios[i]); 426 goto error_disable_reg; 427 } 428 } 429 } 430 } else { 431 st->fixed_addr = true; 432 st->range = AD7266_RANGE_VREF; 433 st->mode = AD7266_MODE_DIFF; 434 } 435 436 spi_set_drvdata(spi, indio_dev); 437 st->spi = spi; 438 439 indio_dev->name = spi_get_device_id(spi)->name; 440 indio_dev->modes = INDIO_DIRECT_MODE; 441 indio_dev->info = &ad7266_info; 442 443 ad7266_init_channels(indio_dev); 444 445 /* wakeup */ 446 st->single_xfer[0].rx_buf = &st->data.sample[0]; 447 st->single_xfer[0].len = 2; 448 st->single_xfer[0].cs_change = 1; 449 /* conversion */ 450 st->single_xfer[1].rx_buf = st->data.sample; 451 st->single_xfer[1].len = 4; 452 st->single_xfer[1].cs_change = 1; 453 /* powerdown */ 454 st->single_xfer[2].tx_buf = &st->data.sample[0]; 455 st->single_xfer[2].len = 1; 456 457 spi_message_init(&st->single_msg); 458 spi_message_add_tail(&st->single_xfer[0], &st->single_msg); 459 spi_message_add_tail(&st->single_xfer[1], &st->single_msg); 460 spi_message_add_tail(&st->single_xfer[2], &st->single_msg); 461 462 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 463 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops); 464 if (ret) 465 goto error_disable_reg; 466 467 ret = iio_device_register(indio_dev); 468 if (ret) 469 goto error_buffer_cleanup; 470 471 return 0; 472 473 error_buffer_cleanup: 474 iio_triggered_buffer_cleanup(indio_dev); 475 error_disable_reg: 476 if (!IS_ERR(st->reg)) 477 regulator_disable(st->reg); 478 479 return ret; 480 } 481 482 static int ad7266_remove(struct spi_device *spi) 483 { 484 struct iio_dev *indio_dev = spi_get_drvdata(spi); 485 struct ad7266_state *st = iio_priv(indio_dev); 486 487 iio_device_unregister(indio_dev); 488 iio_triggered_buffer_cleanup(indio_dev); 489 if (!IS_ERR(st->reg)) 490 regulator_disable(st->reg); 491 492 return 0; 493 } 494 495 static const struct spi_device_id ad7266_id[] = { 496 {"ad7265", 0}, 497 {"ad7266", 0}, 498 { } 499 }; 500 MODULE_DEVICE_TABLE(spi, ad7266_id); 501 502 static struct spi_driver ad7266_driver = { 503 .driver = { 504 .name = "ad7266", 505 }, 506 .probe = ad7266_probe, 507 .remove = ad7266_remove, 508 .id_table = ad7266_id, 509 }; 510 module_spi_driver(ad7266_driver); 511 512 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 513 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC"); 514 MODULE_LICENSE("GPL v2"); 515