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 27 struct ad7266_state { 28 struct spi_device *spi; 29 struct regulator *reg; 30 unsigned long vref_mv; 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 struct { 47 __be16 sample[2]; 48 s64 timestamp; 49 } data ____cacheline_aligned; 50 }; 51 52 static int ad7266_wakeup(struct ad7266_state *st) 53 { 54 /* Any read with >= 2 bytes will wake the device */ 55 return spi_read(st->spi, &st->data.sample[0], 2); 56 } 57 58 static int ad7266_powerdown(struct ad7266_state *st) 59 { 60 /* Any read with < 2 bytes will powerdown the device */ 61 return spi_read(st->spi, &st->data.sample[0], 1); 62 } 63 64 static int ad7266_preenable(struct iio_dev *indio_dev) 65 { 66 struct ad7266_state *st = iio_priv(indio_dev); 67 return ad7266_wakeup(st); 68 } 69 70 static int ad7266_postdisable(struct iio_dev *indio_dev) 71 { 72 struct ad7266_state *st = iio_priv(indio_dev); 73 return ad7266_powerdown(st); 74 } 75 76 static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = { 77 .preenable = &ad7266_preenable, 78 .postenable = &iio_triggered_buffer_postenable, 79 .predisable = &iio_triggered_buffer_predisable, 80 .postdisable = &ad7266_postdisable, 81 }; 82 83 static irqreturn_t ad7266_trigger_handler(int irq, void *p) 84 { 85 struct iio_poll_func *pf = p; 86 struct iio_dev *indio_dev = pf->indio_dev; 87 struct ad7266_state *st = iio_priv(indio_dev); 88 int ret; 89 90 ret = spi_read(st->spi, st->data.sample, 4); 91 if (ret == 0) { 92 iio_push_to_buffers_with_timestamp(indio_dev, &st->data, 93 pf->timestamp); 94 } 95 96 iio_trigger_notify_done(indio_dev->trig); 97 98 return IRQ_HANDLED; 99 } 100 101 static void ad7266_select_input(struct ad7266_state *st, unsigned int nr) 102 { 103 unsigned int i; 104 105 if (st->fixed_addr) 106 return; 107 108 switch (st->mode) { 109 case AD7266_MODE_SINGLE_ENDED: 110 nr >>= 1; 111 break; 112 case AD7266_MODE_PSEUDO_DIFF: 113 nr |= 1; 114 break; 115 case AD7266_MODE_DIFF: 116 nr &= ~1; 117 break; 118 } 119 120 for (i = 0; i < 3; ++i) 121 gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i))); 122 } 123 124 static int ad7266_update_scan_mode(struct iio_dev *indio_dev, 125 const unsigned long *scan_mask) 126 { 127 struct ad7266_state *st = iio_priv(indio_dev); 128 unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength); 129 130 ad7266_select_input(st, nr); 131 132 return 0; 133 } 134 135 static int ad7266_read_single(struct ad7266_state *st, int *val, 136 unsigned int address) 137 { 138 int ret; 139 140 ad7266_select_input(st, address); 141 142 ret = spi_sync(st->spi, &st->single_msg); 143 *val = be16_to_cpu(st->data.sample[address % 2]); 144 145 return ret; 146 } 147 148 static int ad7266_read_raw(struct iio_dev *indio_dev, 149 struct iio_chan_spec const *chan, int *val, int *val2, long m) 150 { 151 struct ad7266_state *st = iio_priv(indio_dev); 152 unsigned long scale_mv; 153 int ret; 154 155 switch (m) { 156 case IIO_CHAN_INFO_RAW: 157 if (iio_buffer_enabled(indio_dev)) 158 return -EBUSY; 159 160 ret = ad7266_read_single(st, val, chan->address); 161 if (ret) 162 return ret; 163 164 *val = (*val >> 2) & 0xfff; 165 if (chan->scan_type.sign == 's') 166 *val = sign_extend32(*val, 11); 167 168 return IIO_VAL_INT; 169 case IIO_CHAN_INFO_SCALE: 170 scale_mv = st->vref_mv; 171 if (st->mode == AD7266_MODE_DIFF) 172 scale_mv *= 2; 173 if (st->range == AD7266_RANGE_2VREF) 174 scale_mv *= 2; 175 176 *val = scale_mv; 177 *val2 = chan->scan_type.realbits; 178 return IIO_VAL_FRACTIONAL_LOG2; 179 case IIO_CHAN_INFO_OFFSET: 180 if (st->range == AD7266_RANGE_2VREF && 181 st->mode != AD7266_MODE_DIFF) 182 *val = 2048; 183 else 184 *val = 0; 185 return IIO_VAL_INT; 186 } 187 return -EINVAL; 188 } 189 190 #define AD7266_CHAN(_chan, _sign) { \ 191 .type = IIO_VOLTAGE, \ 192 .indexed = 1, \ 193 .channel = (_chan), \ 194 .address = (_chan), \ 195 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 196 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 197 | BIT(IIO_CHAN_INFO_OFFSET), \ 198 .scan_index = (_chan), \ 199 .scan_type = { \ 200 .sign = (_sign), \ 201 .realbits = 12, \ 202 .storagebits = 16, \ 203 .shift = 2, \ 204 .endianness = IIO_BE, \ 205 }, \ 206 } 207 208 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \ 209 const struct iio_chan_spec ad7266_channels_##_name[] = { \ 210 AD7266_CHAN(0, (_sign)), \ 211 AD7266_CHAN(1, (_sign)), \ 212 AD7266_CHAN(2, (_sign)), \ 213 AD7266_CHAN(3, (_sign)), \ 214 AD7266_CHAN(4, (_sign)), \ 215 AD7266_CHAN(5, (_sign)), \ 216 AD7266_CHAN(6, (_sign)), \ 217 AD7266_CHAN(7, (_sign)), \ 218 AD7266_CHAN(8, (_sign)), \ 219 AD7266_CHAN(9, (_sign)), \ 220 AD7266_CHAN(10, (_sign)), \ 221 AD7266_CHAN(11, (_sign)), \ 222 IIO_CHAN_SOFT_TIMESTAMP(13), \ 223 } 224 225 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \ 226 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \ 227 AD7266_CHAN(0, (_sign)), \ 228 AD7266_CHAN(1, (_sign)), \ 229 IIO_CHAN_SOFT_TIMESTAMP(2), \ 230 } 231 232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u'); 233 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's'); 234 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u'); 235 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's'); 236 237 #define AD7266_CHAN_DIFF(_chan, _sign) { \ 238 .type = IIO_VOLTAGE, \ 239 .indexed = 1, \ 240 .channel = (_chan) * 2, \ 241 .channel2 = (_chan) * 2 + 1, \ 242 .address = (_chan), \ 243 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 244 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 245 | BIT(IIO_CHAN_INFO_OFFSET), \ 246 .scan_index = (_chan), \ 247 .scan_type = { \ 248 .sign = _sign, \ 249 .realbits = 12, \ 250 .storagebits = 16, \ 251 .shift = 2, \ 252 .endianness = IIO_BE, \ 253 }, \ 254 .differential = 1, \ 255 } 256 257 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \ 258 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \ 259 AD7266_CHAN_DIFF(0, (_sign)), \ 260 AD7266_CHAN_DIFF(1, (_sign)), \ 261 AD7266_CHAN_DIFF(2, (_sign)), \ 262 AD7266_CHAN_DIFF(3, (_sign)), \ 263 AD7266_CHAN_DIFF(4, (_sign)), \ 264 AD7266_CHAN_DIFF(5, (_sign)), \ 265 IIO_CHAN_SOFT_TIMESTAMP(6), \ 266 } 267 268 static AD7266_DECLARE_DIFF_CHANNELS(s, 's'); 269 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u'); 270 271 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \ 272 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \ 273 AD7266_CHAN_DIFF(0, (_sign)), \ 274 AD7266_CHAN_DIFF(1, (_sign)), \ 275 IIO_CHAN_SOFT_TIMESTAMP(2), \ 276 } 277 278 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's'); 279 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u'); 280 281 static const struct iio_info ad7266_info = { 282 .read_raw = &ad7266_read_raw, 283 .update_scan_mode = &ad7266_update_scan_mode, 284 .driver_module = THIS_MODULE, 285 }; 286 287 static const unsigned long ad7266_available_scan_masks[] = { 288 0x003, 289 0x00c, 290 0x030, 291 0x0c0, 292 0x300, 293 0xc00, 294 0x000, 295 }; 296 297 static const unsigned long ad7266_available_scan_masks_diff[] = { 298 0x003, 299 0x00c, 300 0x030, 301 0x000, 302 }; 303 304 static const unsigned long ad7266_available_scan_masks_fixed[] = { 305 0x003, 306 0x000, 307 }; 308 309 struct ad7266_chan_info { 310 const struct iio_chan_spec *channels; 311 unsigned int num_channels; 312 const unsigned long *scan_masks; 313 }; 314 315 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \ 316 (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0)) 317 318 static const struct ad7266_chan_info ad7266_chan_infos[] = { 319 [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = { 320 .channels = ad7266_channels_u, 321 .num_channels = ARRAY_SIZE(ad7266_channels_u), 322 .scan_masks = ad7266_available_scan_masks, 323 }, 324 [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = { 325 .channels = ad7266_channels_u_fixed, 326 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed), 327 .scan_masks = ad7266_available_scan_masks_fixed, 328 }, 329 [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = { 330 .channels = ad7266_channels_s, 331 .num_channels = ARRAY_SIZE(ad7266_channels_s), 332 .scan_masks = ad7266_available_scan_masks, 333 }, 334 [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = { 335 .channels = ad7266_channels_s_fixed, 336 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed), 337 .scan_masks = ad7266_available_scan_masks_fixed, 338 }, 339 [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = { 340 .channels = ad7266_channels_diff_u, 341 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u), 342 .scan_masks = ad7266_available_scan_masks_diff, 343 }, 344 [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = { 345 .channels = ad7266_channels_diff_fixed_u, 346 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u), 347 .scan_masks = ad7266_available_scan_masks_fixed, 348 }, 349 [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = { 350 .channels = ad7266_channels_diff_s, 351 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s), 352 .scan_masks = ad7266_available_scan_masks_diff, 353 }, 354 [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = { 355 .channels = ad7266_channels_diff_fixed_s, 356 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s), 357 .scan_masks = ad7266_available_scan_masks_fixed, 358 }, 359 }; 360 361 static void ad7266_init_channels(struct iio_dev *indio_dev) 362 { 363 struct ad7266_state *st = iio_priv(indio_dev); 364 bool is_differential, is_signed; 365 const struct ad7266_chan_info *chan_info; 366 int i; 367 368 is_differential = st->mode != AD7266_MODE_SINGLE_ENDED; 369 is_signed = (st->range == AD7266_RANGE_2VREF) | 370 (st->mode == AD7266_MODE_DIFF); 371 372 i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr); 373 chan_info = &ad7266_chan_infos[i]; 374 375 indio_dev->channels = chan_info->channels; 376 indio_dev->num_channels = chan_info->num_channels; 377 indio_dev->available_scan_masks = chan_info->scan_masks; 378 indio_dev->masklength = chan_info->num_channels - 1; 379 } 380 381 static const char * const ad7266_gpio_labels[] = { 382 "AD0", "AD1", "AD2", 383 }; 384 385 static int ad7266_probe(struct spi_device *spi) 386 { 387 struct ad7266_platform_data *pdata = spi->dev.platform_data; 388 struct iio_dev *indio_dev; 389 struct ad7266_state *st; 390 unsigned int i; 391 int ret; 392 393 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 394 if (indio_dev == NULL) 395 return -ENOMEM; 396 397 st = iio_priv(indio_dev); 398 399 st->reg = devm_regulator_get(&spi->dev, "vref"); 400 if (!IS_ERR_OR_NULL(st->reg)) { 401 ret = regulator_enable(st->reg); 402 if (ret) 403 return ret; 404 405 ret = regulator_get_voltage(st->reg); 406 if (ret < 0) 407 goto error_disable_reg; 408 409 st->vref_mv = ret / 1000; 410 } else { 411 /* Use internal reference */ 412 st->vref_mv = 2500; 413 } 414 415 if (pdata) { 416 st->fixed_addr = pdata->fixed_addr; 417 st->mode = pdata->mode; 418 st->range = pdata->range; 419 420 if (!st->fixed_addr) { 421 for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) { 422 st->gpios[i].gpio = pdata->addr_gpios[i]; 423 st->gpios[i].flags = GPIOF_OUT_INIT_LOW; 424 st->gpios[i].label = ad7266_gpio_labels[i]; 425 } 426 ret = gpio_request_array(st->gpios, 427 ARRAY_SIZE(st->gpios)); 428 if (ret) 429 goto error_disable_reg; 430 } 431 } else { 432 st->fixed_addr = true; 433 st->range = AD7266_RANGE_VREF; 434 st->mode = AD7266_MODE_DIFF; 435 } 436 437 spi_set_drvdata(spi, indio_dev); 438 st->spi = spi; 439 440 indio_dev->dev.parent = &spi->dev; 441 indio_dev->name = spi_get_device_id(spi)->name; 442 indio_dev->modes = INDIO_DIRECT_MODE; 443 indio_dev->info = &ad7266_info; 444 445 ad7266_init_channels(indio_dev); 446 447 /* wakeup */ 448 st->single_xfer[0].rx_buf = &st->data.sample[0]; 449 st->single_xfer[0].len = 2; 450 st->single_xfer[0].cs_change = 1; 451 /* conversion */ 452 st->single_xfer[1].rx_buf = st->data.sample; 453 st->single_xfer[1].len = 4; 454 st->single_xfer[1].cs_change = 1; 455 /* powerdown */ 456 st->single_xfer[2].tx_buf = &st->data.sample[0]; 457 st->single_xfer[2].len = 1; 458 459 spi_message_init(&st->single_msg); 460 spi_message_add_tail(&st->single_xfer[0], &st->single_msg); 461 spi_message_add_tail(&st->single_xfer[1], &st->single_msg); 462 spi_message_add_tail(&st->single_xfer[2], &st->single_msg); 463 464 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 465 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops); 466 if (ret) 467 goto error_free_gpios; 468 469 ret = iio_device_register(indio_dev); 470 if (ret) 471 goto error_buffer_cleanup; 472 473 return 0; 474 475 error_buffer_cleanup: 476 iio_triggered_buffer_cleanup(indio_dev); 477 error_free_gpios: 478 if (!st->fixed_addr) 479 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); 480 error_disable_reg: 481 if (!IS_ERR_OR_NULL(st->reg)) 482 regulator_disable(st->reg); 483 484 return ret; 485 } 486 487 static int ad7266_remove(struct spi_device *spi) 488 { 489 struct iio_dev *indio_dev = spi_get_drvdata(spi); 490 struct ad7266_state *st = iio_priv(indio_dev); 491 492 iio_device_unregister(indio_dev); 493 iio_triggered_buffer_cleanup(indio_dev); 494 if (!st->fixed_addr) 495 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); 496 if (!IS_ERR_OR_NULL(st->reg)) 497 regulator_disable(st->reg); 498 499 return 0; 500 } 501 502 static const struct spi_device_id ad7266_id[] = { 503 {"ad7265", 0}, 504 {"ad7266", 0}, 505 { } 506 }; 507 MODULE_DEVICE_TABLE(spi, ad7266_id); 508 509 static struct spi_driver ad7266_driver = { 510 .driver = { 511 .name = "ad7266", 512 .owner = THIS_MODULE, 513 }, 514 .probe = ad7266_probe, 515 .remove = ad7266_remove, 516 .id_table = ad7266_id, 517 }; 518 module_spi_driver(ad7266_driver); 519 520 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 521 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC"); 522 MODULE_LICENSE("GPL v2"); 523