ad7266.c revision fce8abfda40a764f4662ee354c1646ec78061371
1/* 2 * AD7266/65 SPI ADC driver 3 * 4 * Copyright 2012 Analog Devices Inc. 5 * 6 * Licensed under the GPL-2. 7 */ 8 9#include <linux/device.h> 10#include <linux/kernel.h> 11#include <linux/slab.h> 12#include <linux/spi/spi.h> 13#include <linux/regulator/consumer.h> 14#include <linux/err.h> 15#include <linux/gpio.h> 16#include <linux/module.h> 17 18#include <linux/interrupt.h> 19 20#include <linux/iio/iio.h> 21#include <linux/iio/buffer.h> 22#include <linux/iio/trigger_consumer.h> 23#include <linux/iio/triggered_buffer.h> 24 25#include <linux/platform_data/ad7266.h> 26 27struct ad7266_state { 28 struct spi_device *spi; 29 struct regulator *reg; 30 unsigned long vref_uv; 31 32 struct spi_transfer single_xfer[3]; 33 struct spi_message single_msg; 34 35 enum ad7266_range range; 36 enum ad7266_mode mode; 37 bool fixed_addr; 38 struct gpio gpios[3]; 39 40 /* 41 * DMA (thus cache coherency maintenance) requires the 42 * transfer buffers to live in their own cache lines. 43 * The buffer needs to be large enough to hold two samples (4 bytes) and 44 * the naturally aligned timestamp (8 bytes). 45 */ 46 uint8_t data[ALIGN(4, sizeof(s64)) + sizeof(s64)] ____cacheline_aligned; 47}; 48 49static int ad7266_wakeup(struct ad7266_state *st) 50{ 51 /* Any read with >= 2 bytes will wake the device */ 52 return spi_read(st->spi, st->data, 2); 53} 54 55static int ad7266_powerdown(struct ad7266_state *st) 56{ 57 /* Any read with < 2 bytes will powerdown the device */ 58 return spi_read(st->spi, st->data, 1); 59} 60 61static int ad7266_preenable(struct iio_dev *indio_dev) 62{ 63 struct ad7266_state *st = iio_priv(indio_dev); 64 int ret; 65 66 ret = ad7266_wakeup(st); 67 if (ret) 68 return ret; 69 70 ret = iio_sw_buffer_preenable(indio_dev); 71 if (ret) 72 ad7266_powerdown(st); 73 74 return ret; 75} 76 77static int ad7266_postdisable(struct iio_dev *indio_dev) 78{ 79 struct ad7266_state *st = iio_priv(indio_dev); 80 return ad7266_powerdown(st); 81} 82 83static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = { 84 .preenable = &ad7266_preenable, 85 .postenable = &iio_triggered_buffer_postenable, 86 .predisable = &iio_triggered_buffer_predisable, 87 .postdisable = &ad7266_postdisable, 88}; 89 90static irqreturn_t ad7266_trigger_handler(int irq, void *p) 91{ 92 struct iio_poll_func *pf = p; 93 struct iio_dev *indio_dev = pf->indio_dev; 94 struct ad7266_state *st = iio_priv(indio_dev); 95 int ret; 96 97 ret = spi_read(st->spi, st->data, 4); 98 if (ret == 0) { 99 iio_push_to_buffers_with_timestamp(indio_dev, st->data, 100 pf->timestamp); 101 } 102 103 iio_trigger_notify_done(indio_dev->trig); 104 105 return IRQ_HANDLED; 106} 107 108static void ad7266_select_input(struct ad7266_state *st, unsigned int nr) 109{ 110 unsigned int i; 111 112 if (st->fixed_addr) 113 return; 114 115 switch (st->mode) { 116 case AD7266_MODE_SINGLE_ENDED: 117 nr >>= 1; 118 break; 119 case AD7266_MODE_PSEUDO_DIFF: 120 nr |= 1; 121 break; 122 case AD7266_MODE_DIFF: 123 nr &= ~1; 124 break; 125 } 126 127 for (i = 0; i < 3; ++i) 128 gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i))); 129} 130 131static int ad7266_update_scan_mode(struct iio_dev *indio_dev, 132 const unsigned long *scan_mask) 133{ 134 struct ad7266_state *st = iio_priv(indio_dev); 135 unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength); 136 137 ad7266_select_input(st, nr); 138 139 return 0; 140} 141 142static int ad7266_read_single(struct ad7266_state *st, int *val, 143 unsigned int address) 144{ 145 int ret; 146 147 ad7266_select_input(st, address); 148 149 ret = spi_sync(st->spi, &st->single_msg); 150 *val = be16_to_cpu(st->data[address % 2]); 151 152 return ret; 153} 154 155static int ad7266_read_raw(struct iio_dev *indio_dev, 156 struct iio_chan_spec const *chan, int *val, int *val2, long m) 157{ 158 struct ad7266_state *st = iio_priv(indio_dev); 159 unsigned long scale_uv; 160 int ret; 161 162 switch (m) { 163 case IIO_CHAN_INFO_RAW: 164 if (iio_buffer_enabled(indio_dev)) 165 return -EBUSY; 166 167 ret = ad7266_read_single(st, val, chan->address); 168 if (ret) 169 return ret; 170 171 *val = (*val >> 2) & 0xfff; 172 if (chan->scan_type.sign == 's') 173 *val = sign_extend32(*val, 11); 174 175 return IIO_VAL_INT; 176 case IIO_CHAN_INFO_SCALE: 177 scale_uv = (st->vref_uv * 100); 178 if (st->mode == AD7266_MODE_DIFF) 179 scale_uv *= 2; 180 if (st->range == AD7266_RANGE_2VREF) 181 scale_uv *= 2; 182 183 scale_uv >>= chan->scan_type.realbits; 184 *val = scale_uv / 100000; 185 *val2 = (scale_uv % 100000) * 10; 186 return IIO_VAL_INT_PLUS_MICRO; 187 case IIO_CHAN_INFO_OFFSET: 188 if (st->range == AD7266_RANGE_2VREF && 189 st->mode != AD7266_MODE_DIFF) 190 *val = 2048; 191 else 192 *val = 0; 193 return IIO_VAL_INT; 194 } 195 return -EINVAL; 196} 197 198#define AD7266_CHAN(_chan, _sign) { \ 199 .type = IIO_VOLTAGE, \ 200 .indexed = 1, \ 201 .channel = (_chan), \ 202 .address = (_chan), \ 203 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 204 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 205 | BIT(IIO_CHAN_INFO_OFFSET), \ 206 .scan_index = (_chan), \ 207 .scan_type = { \ 208 .sign = (_sign), \ 209 .realbits = 12, \ 210 .storagebits = 16, \ 211 .shift = 2, \ 212 .endianness = IIO_BE, \ 213 }, \ 214} 215 216#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \ 217const struct iio_chan_spec ad7266_channels_##_name[] = { \ 218 AD7266_CHAN(0, (_sign)), \ 219 AD7266_CHAN(1, (_sign)), \ 220 AD7266_CHAN(2, (_sign)), \ 221 AD7266_CHAN(3, (_sign)), \ 222 AD7266_CHAN(4, (_sign)), \ 223 AD7266_CHAN(5, (_sign)), \ 224 AD7266_CHAN(6, (_sign)), \ 225 AD7266_CHAN(7, (_sign)), \ 226 AD7266_CHAN(8, (_sign)), \ 227 AD7266_CHAN(9, (_sign)), \ 228 AD7266_CHAN(10, (_sign)), \ 229 AD7266_CHAN(11, (_sign)), \ 230 IIO_CHAN_SOFT_TIMESTAMP(13), \ 231} 232 233#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \ 234const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \ 235 AD7266_CHAN(0, (_sign)), \ 236 AD7266_CHAN(1, (_sign)), \ 237 IIO_CHAN_SOFT_TIMESTAMP(2), \ 238} 239 240static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u'); 241static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's'); 242static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u'); 243static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's'); 244 245#define AD7266_CHAN_DIFF(_chan, _sign) { \ 246 .type = IIO_VOLTAGE, \ 247 .indexed = 1, \ 248 .channel = (_chan) * 2, \ 249 .channel2 = (_chan) * 2 + 1, \ 250 .address = (_chan), \ 251 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 252 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 253 | BIT(IIO_CHAN_INFO_OFFSET), \ 254 .scan_index = (_chan), \ 255 .scan_type = { \ 256 .sign = _sign, \ 257 .realbits = 12, \ 258 .storagebits = 16, \ 259 .shift = 2, \ 260 .endianness = IIO_BE, \ 261 }, \ 262 .differential = 1, \ 263} 264 265#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \ 266const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \ 267 AD7266_CHAN_DIFF(0, (_sign)), \ 268 AD7266_CHAN_DIFF(1, (_sign)), \ 269 AD7266_CHAN_DIFF(2, (_sign)), \ 270 AD7266_CHAN_DIFF(3, (_sign)), \ 271 AD7266_CHAN_DIFF(4, (_sign)), \ 272 AD7266_CHAN_DIFF(5, (_sign)), \ 273 IIO_CHAN_SOFT_TIMESTAMP(6), \ 274} 275 276static AD7266_DECLARE_DIFF_CHANNELS(s, 's'); 277static AD7266_DECLARE_DIFF_CHANNELS(u, 'u'); 278 279#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \ 280const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \ 281 AD7266_CHAN_DIFF(0, (_sign)), \ 282 AD7266_CHAN_DIFF(1, (_sign)), \ 283 IIO_CHAN_SOFT_TIMESTAMP(2), \ 284} 285 286static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's'); 287static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u'); 288 289static const struct iio_info ad7266_info = { 290 .read_raw = &ad7266_read_raw, 291 .update_scan_mode = &ad7266_update_scan_mode, 292 .driver_module = THIS_MODULE, 293}; 294 295static const unsigned long ad7266_available_scan_masks[] = { 296 0x003, 297 0x00c, 298 0x030, 299 0x0c0, 300 0x300, 301 0xc00, 302 0x000, 303}; 304 305static const unsigned long ad7266_available_scan_masks_diff[] = { 306 0x003, 307 0x00c, 308 0x030, 309 0x000, 310}; 311 312static const unsigned long ad7266_available_scan_masks_fixed[] = { 313 0x003, 314 0x000, 315}; 316 317struct ad7266_chan_info { 318 const struct iio_chan_spec *channels; 319 unsigned int num_channels; 320 const unsigned long *scan_masks; 321}; 322 323#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \ 324 (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0)) 325 326static const struct ad7266_chan_info ad7266_chan_infos[] = { 327 [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = { 328 .channels = ad7266_channels_u, 329 .num_channels = ARRAY_SIZE(ad7266_channels_u), 330 .scan_masks = ad7266_available_scan_masks, 331 }, 332 [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = { 333 .channels = ad7266_channels_u_fixed, 334 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed), 335 .scan_masks = ad7266_available_scan_masks_fixed, 336 }, 337 [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = { 338 .channels = ad7266_channels_s, 339 .num_channels = ARRAY_SIZE(ad7266_channels_s), 340 .scan_masks = ad7266_available_scan_masks, 341 }, 342 [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = { 343 .channels = ad7266_channels_s_fixed, 344 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed), 345 .scan_masks = ad7266_available_scan_masks_fixed, 346 }, 347 [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = { 348 .channels = ad7266_channels_diff_u, 349 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u), 350 .scan_masks = ad7266_available_scan_masks_diff, 351 }, 352 [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = { 353 .channels = ad7266_channels_diff_fixed_u, 354 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u), 355 .scan_masks = ad7266_available_scan_masks_fixed, 356 }, 357 [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = { 358 .channels = ad7266_channels_diff_s, 359 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s), 360 .scan_masks = ad7266_available_scan_masks_diff, 361 }, 362 [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = { 363 .channels = ad7266_channels_diff_fixed_s, 364 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s), 365 .scan_masks = ad7266_available_scan_masks_fixed, 366 }, 367}; 368 369static void ad7266_init_channels(struct iio_dev *indio_dev) 370{ 371 struct ad7266_state *st = iio_priv(indio_dev); 372 bool is_differential, is_signed; 373 const struct ad7266_chan_info *chan_info; 374 int i; 375 376 is_differential = st->mode != AD7266_MODE_SINGLE_ENDED; 377 is_signed = (st->range == AD7266_RANGE_2VREF) | 378 (st->mode == AD7266_MODE_DIFF); 379 380 i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr); 381 chan_info = &ad7266_chan_infos[i]; 382 383 indio_dev->channels = chan_info->channels; 384 indio_dev->num_channels = chan_info->num_channels; 385 indio_dev->available_scan_masks = chan_info->scan_masks; 386 indio_dev->masklength = chan_info->num_channels - 1; 387} 388 389static const char * const ad7266_gpio_labels[] = { 390 "AD0", "AD1", "AD2", 391}; 392 393static int ad7266_probe(struct spi_device *spi) 394{ 395 struct ad7266_platform_data *pdata = spi->dev.platform_data; 396 struct iio_dev *indio_dev; 397 struct ad7266_state *st; 398 unsigned int i; 399 int ret; 400 401 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 402 if (indio_dev == NULL) 403 return -ENOMEM; 404 405 st = iio_priv(indio_dev); 406 407 st->reg = devm_regulator_get(&spi->dev, "vref"); 408 if (!IS_ERR_OR_NULL(st->reg)) { 409 ret = regulator_enable(st->reg); 410 if (ret) 411 return ret; 412 413 ret = regulator_get_voltage(st->reg); 414 if (ret < 0) 415 goto error_disable_reg; 416 417 st->vref_uv = ret; 418 } else { 419 /* Use internal reference */ 420 st->vref_uv = 2500000; 421 } 422 423 if (pdata) { 424 st->fixed_addr = pdata->fixed_addr; 425 st->mode = pdata->mode; 426 st->range = pdata->range; 427 428 if (!st->fixed_addr) { 429 for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) { 430 st->gpios[i].gpio = pdata->addr_gpios[i]; 431 st->gpios[i].flags = GPIOF_OUT_INIT_LOW; 432 st->gpios[i].label = ad7266_gpio_labels[i]; 433 } 434 ret = gpio_request_array(st->gpios, 435 ARRAY_SIZE(st->gpios)); 436 if (ret) 437 goto error_disable_reg; 438 } 439 } else { 440 st->fixed_addr = true; 441 st->range = AD7266_RANGE_VREF; 442 st->mode = AD7266_MODE_DIFF; 443 } 444 445 spi_set_drvdata(spi, indio_dev); 446 st->spi = spi; 447 448 indio_dev->dev.parent = &spi->dev; 449 indio_dev->name = spi_get_device_id(spi)->name; 450 indio_dev->modes = INDIO_DIRECT_MODE; 451 indio_dev->info = &ad7266_info; 452 453 ad7266_init_channels(indio_dev); 454 455 /* wakeup */ 456 st->single_xfer[0].rx_buf = &st->data; 457 st->single_xfer[0].len = 2; 458 st->single_xfer[0].cs_change = 1; 459 /* conversion */ 460 st->single_xfer[1].rx_buf = &st->data; 461 st->single_xfer[1].len = 4; 462 st->single_xfer[1].cs_change = 1; 463 /* powerdown */ 464 st->single_xfer[2].tx_buf = &st->data; 465 st->single_xfer[2].len = 1; 466 467 spi_message_init(&st->single_msg); 468 spi_message_add_tail(&st->single_xfer[0], &st->single_msg); 469 spi_message_add_tail(&st->single_xfer[1], &st->single_msg); 470 spi_message_add_tail(&st->single_xfer[2], &st->single_msg); 471 472 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 473 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops); 474 if (ret) 475 goto error_free_gpios; 476 477 ret = iio_device_register(indio_dev); 478 if (ret) 479 goto error_buffer_cleanup; 480 481 return 0; 482 483error_buffer_cleanup: 484 iio_triggered_buffer_cleanup(indio_dev); 485error_free_gpios: 486 if (!st->fixed_addr) 487 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); 488error_disable_reg: 489 if (!IS_ERR_OR_NULL(st->reg)) 490 regulator_disable(st->reg); 491 492 return ret; 493} 494 495static int ad7266_remove(struct spi_device *spi) 496{ 497 struct iio_dev *indio_dev = spi_get_drvdata(spi); 498 struct ad7266_state *st = iio_priv(indio_dev); 499 500 iio_device_unregister(indio_dev); 501 iio_triggered_buffer_cleanup(indio_dev); 502 if (!st->fixed_addr) 503 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); 504 if (!IS_ERR_OR_NULL(st->reg)) 505 regulator_disable(st->reg); 506 507 return 0; 508} 509 510static const struct spi_device_id ad7266_id[] = { 511 {"ad7265", 0}, 512 {"ad7266", 0}, 513 { } 514}; 515MODULE_DEVICE_TABLE(spi, ad7266_id); 516 517static struct spi_driver ad7266_driver = { 518 .driver = { 519 .name = "ad7266", 520 .owner = THIS_MODULE, 521 }, 522 .probe = ad7266_probe, 523 .remove = ad7266_remove, 524 .id_table = ad7266_id, 525}; 526module_spi_driver(ad7266_driver); 527 528MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 529MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC"); 530MODULE_LICENSE("GPL v2"); 531