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, 11); 163 164 return IIO_VAL_INT; 165 case IIO_CHAN_INFO_SCALE: 166 scale_mv = st->vref_mv; 167 if (st->mode == AD7266_MODE_DIFF) 168 scale_mv *= 2; 169 if (st->range == AD7266_RANGE_2VREF) 170 scale_mv *= 2; 171 172 *val = scale_mv; 173 *val2 = chan->scan_type.realbits; 174 return IIO_VAL_FRACTIONAL_LOG2; 175 case IIO_CHAN_INFO_OFFSET: 176 if (st->range == AD7266_RANGE_2VREF && 177 st->mode != AD7266_MODE_DIFF) 178 *val = 2048; 179 else 180 *val = 0; 181 return IIO_VAL_INT; 182 } 183 return -EINVAL; 184 } 185 186 #define AD7266_CHAN(_chan, _sign) { \ 187 .type = IIO_VOLTAGE, \ 188 .indexed = 1, \ 189 .channel = (_chan), \ 190 .address = (_chan), \ 191 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 192 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 193 | BIT(IIO_CHAN_INFO_OFFSET), \ 194 .scan_index = (_chan), \ 195 .scan_type = { \ 196 .sign = (_sign), \ 197 .realbits = 12, \ 198 .storagebits = 16, \ 199 .shift = 2, \ 200 .endianness = IIO_BE, \ 201 }, \ 202 } 203 204 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \ 205 const struct iio_chan_spec ad7266_channels_##_name[] = { \ 206 AD7266_CHAN(0, (_sign)), \ 207 AD7266_CHAN(1, (_sign)), \ 208 AD7266_CHAN(2, (_sign)), \ 209 AD7266_CHAN(3, (_sign)), \ 210 AD7266_CHAN(4, (_sign)), \ 211 AD7266_CHAN(5, (_sign)), \ 212 AD7266_CHAN(6, (_sign)), \ 213 AD7266_CHAN(7, (_sign)), \ 214 AD7266_CHAN(8, (_sign)), \ 215 AD7266_CHAN(9, (_sign)), \ 216 AD7266_CHAN(10, (_sign)), \ 217 AD7266_CHAN(11, (_sign)), \ 218 IIO_CHAN_SOFT_TIMESTAMP(13), \ 219 } 220 221 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \ 222 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \ 223 AD7266_CHAN(0, (_sign)), \ 224 AD7266_CHAN(1, (_sign)), \ 225 IIO_CHAN_SOFT_TIMESTAMP(2), \ 226 } 227 228 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u'); 229 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's'); 230 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u'); 231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's'); 232 233 #define AD7266_CHAN_DIFF(_chan, _sign) { \ 234 .type = IIO_VOLTAGE, \ 235 .indexed = 1, \ 236 .channel = (_chan) * 2, \ 237 .channel2 = (_chan) * 2 + 1, \ 238 .address = (_chan), \ 239 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 240 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 241 | BIT(IIO_CHAN_INFO_OFFSET), \ 242 .scan_index = (_chan), \ 243 .scan_type = { \ 244 .sign = _sign, \ 245 .realbits = 12, \ 246 .storagebits = 16, \ 247 .shift = 2, \ 248 .endianness = IIO_BE, \ 249 }, \ 250 .differential = 1, \ 251 } 252 253 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \ 254 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \ 255 AD7266_CHAN_DIFF(0, (_sign)), \ 256 AD7266_CHAN_DIFF(1, (_sign)), \ 257 AD7266_CHAN_DIFF(2, (_sign)), \ 258 AD7266_CHAN_DIFF(3, (_sign)), \ 259 AD7266_CHAN_DIFF(4, (_sign)), \ 260 AD7266_CHAN_DIFF(5, (_sign)), \ 261 IIO_CHAN_SOFT_TIMESTAMP(6), \ 262 } 263 264 static AD7266_DECLARE_DIFF_CHANNELS(s, 's'); 265 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u'); 266 267 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \ 268 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \ 269 AD7266_CHAN_DIFF(0, (_sign)), \ 270 AD7266_CHAN_DIFF(1, (_sign)), \ 271 IIO_CHAN_SOFT_TIMESTAMP(2), \ 272 } 273 274 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's'); 275 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u'); 276 277 static const struct iio_info ad7266_info = { 278 .read_raw = &ad7266_read_raw, 279 .update_scan_mode = &ad7266_update_scan_mode, 280 }; 281 282 static const unsigned long ad7266_available_scan_masks[] = { 283 0x003, 284 0x00c, 285 0x030, 286 0x0c0, 287 0x300, 288 0xc00, 289 0x000, 290 }; 291 292 static const unsigned long ad7266_available_scan_masks_diff[] = { 293 0x003, 294 0x00c, 295 0x030, 296 0x000, 297 }; 298 299 static const unsigned long ad7266_available_scan_masks_fixed[] = { 300 0x003, 301 0x000, 302 }; 303 304 struct ad7266_chan_info { 305 const struct iio_chan_spec *channels; 306 unsigned int num_channels; 307 const unsigned long *scan_masks; 308 }; 309 310 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \ 311 (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0)) 312 313 static const struct ad7266_chan_info ad7266_chan_infos[] = { 314 [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = { 315 .channels = ad7266_channels_u, 316 .num_channels = ARRAY_SIZE(ad7266_channels_u), 317 .scan_masks = ad7266_available_scan_masks, 318 }, 319 [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = { 320 .channels = ad7266_channels_u_fixed, 321 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed), 322 .scan_masks = ad7266_available_scan_masks_fixed, 323 }, 324 [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = { 325 .channels = ad7266_channels_s, 326 .num_channels = ARRAY_SIZE(ad7266_channels_s), 327 .scan_masks = ad7266_available_scan_masks, 328 }, 329 [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = { 330 .channels = ad7266_channels_s_fixed, 331 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed), 332 .scan_masks = ad7266_available_scan_masks_fixed, 333 }, 334 [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = { 335 .channels = ad7266_channels_diff_u, 336 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u), 337 .scan_masks = ad7266_available_scan_masks_diff, 338 }, 339 [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = { 340 .channels = ad7266_channels_diff_fixed_u, 341 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u), 342 .scan_masks = ad7266_available_scan_masks_fixed, 343 }, 344 [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = { 345 .channels = ad7266_channels_diff_s, 346 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s), 347 .scan_masks = ad7266_available_scan_masks_diff, 348 }, 349 [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = { 350 .channels = ad7266_channels_diff_fixed_s, 351 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s), 352 .scan_masks = ad7266_available_scan_masks_fixed, 353 }, 354 }; 355 356 static void ad7266_init_channels(struct iio_dev *indio_dev) 357 { 358 struct ad7266_state *st = iio_priv(indio_dev); 359 bool is_differential, is_signed; 360 const struct ad7266_chan_info *chan_info; 361 int i; 362 363 is_differential = st->mode != AD7266_MODE_SINGLE_ENDED; 364 is_signed = (st->range == AD7266_RANGE_2VREF) | 365 (st->mode == AD7266_MODE_DIFF); 366 367 i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr); 368 chan_info = &ad7266_chan_infos[i]; 369 370 indio_dev->channels = chan_info->channels; 371 indio_dev->num_channels = chan_info->num_channels; 372 indio_dev->available_scan_masks = chan_info->scan_masks; 373 indio_dev->masklength = chan_info->num_channels - 1; 374 } 375 376 static const char * const ad7266_gpio_labels[] = { 377 "ad0", "ad1", "ad2", 378 }; 379 380 static int ad7266_probe(struct spi_device *spi) 381 { 382 struct ad7266_platform_data *pdata = spi->dev.platform_data; 383 struct iio_dev *indio_dev; 384 struct ad7266_state *st; 385 unsigned int i; 386 int ret; 387 388 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 389 if (indio_dev == NULL) 390 return -ENOMEM; 391 392 st = iio_priv(indio_dev); 393 394 st->reg = devm_regulator_get_optional(&spi->dev, "vref"); 395 if (!IS_ERR(st->reg)) { 396 ret = regulator_enable(st->reg); 397 if (ret) 398 return ret; 399 400 ret = regulator_get_voltage(st->reg); 401 if (ret < 0) 402 goto error_disable_reg; 403 404 st->vref_mv = ret / 1000; 405 } else { 406 /* Any other error indicates that the regulator does exist */ 407 if (PTR_ERR(st->reg) != -ENODEV) 408 return PTR_ERR(st->reg); 409 /* Use internal reference */ 410 st->vref_mv = 2500; 411 } 412 413 if (pdata) { 414 st->fixed_addr = pdata->fixed_addr; 415 st->mode = pdata->mode; 416 st->range = pdata->range; 417 418 if (!st->fixed_addr) { 419 for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) { 420 st->gpios[i] = devm_gpiod_get(&spi->dev, 421 ad7266_gpio_labels[i], 422 GPIOD_OUT_LOW); 423 if (IS_ERR(st->gpios[i])) { 424 ret = PTR_ERR(st->gpios[i]); 425 goto error_disable_reg; 426 } 427 } 428 } 429 } else { 430 st->fixed_addr = true; 431 st->range = AD7266_RANGE_VREF; 432 st->mode = AD7266_MODE_DIFF; 433 } 434 435 spi_set_drvdata(spi, indio_dev); 436 st->spi = spi; 437 438 indio_dev->name = spi_get_device_id(spi)->name; 439 indio_dev->modes = INDIO_DIRECT_MODE; 440 indio_dev->info = &ad7266_info; 441 442 ad7266_init_channels(indio_dev); 443 444 /* wakeup */ 445 st->single_xfer[0].rx_buf = &st->data.sample[0]; 446 st->single_xfer[0].len = 2; 447 st->single_xfer[0].cs_change = 1; 448 /* conversion */ 449 st->single_xfer[1].rx_buf = st->data.sample; 450 st->single_xfer[1].len = 4; 451 st->single_xfer[1].cs_change = 1; 452 /* powerdown */ 453 st->single_xfer[2].tx_buf = &st->data.sample[0]; 454 st->single_xfer[2].len = 1; 455 456 spi_message_init(&st->single_msg); 457 spi_message_add_tail(&st->single_xfer[0], &st->single_msg); 458 spi_message_add_tail(&st->single_xfer[1], &st->single_msg); 459 spi_message_add_tail(&st->single_xfer[2], &st->single_msg); 460 461 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 462 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops); 463 if (ret) 464 goto error_disable_reg; 465 466 ret = iio_device_register(indio_dev); 467 if (ret) 468 goto error_buffer_cleanup; 469 470 return 0; 471 472 error_buffer_cleanup: 473 iio_triggered_buffer_cleanup(indio_dev); 474 error_disable_reg: 475 if (!IS_ERR(st->reg)) 476 regulator_disable(st->reg); 477 478 return ret; 479 } 480 481 static int ad7266_remove(struct spi_device *spi) 482 { 483 struct iio_dev *indio_dev = spi_get_drvdata(spi); 484 struct ad7266_state *st = iio_priv(indio_dev); 485 486 iio_device_unregister(indio_dev); 487 iio_triggered_buffer_cleanup(indio_dev); 488 if (!IS_ERR(st->reg)) 489 regulator_disable(st->reg); 490 491 return 0; 492 } 493 494 static const struct spi_device_id ad7266_id[] = { 495 {"ad7265", 0}, 496 {"ad7266", 0}, 497 { } 498 }; 499 MODULE_DEVICE_TABLE(spi, ad7266_id); 500 501 static struct spi_driver ad7266_driver = { 502 .driver = { 503 .name = "ad7266", 504 }, 505 .probe = ad7266_probe, 506 .remove = ad7266_remove, 507 .id_table = ad7266_id, 508 }; 509 module_spi_driver(ad7266_driver); 510 511 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 512 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC"); 513 MODULE_LICENSE("GPL v2"); 514