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 ret = iio_device_claim_direct_mode(indio_dev); 158 if (ret) 159 return ret; 160 ret = ad7266_read_single(st, val, chan->address); 161 iio_device_release_direct_mode(indio_dev); 162 163 *val = (*val >> 2) & 0xfff; 164 if (chan->scan_type.sign == 's') 165 *val = sign_extend32(*val, 11); 166 167 return IIO_VAL_INT; 168 case IIO_CHAN_INFO_SCALE: 169 scale_mv = st->vref_mv; 170 if (st->mode == AD7266_MODE_DIFF) 171 scale_mv *= 2; 172 if (st->range == AD7266_RANGE_2VREF) 173 scale_mv *= 2; 174 175 *val = scale_mv; 176 *val2 = chan->scan_type.realbits; 177 return IIO_VAL_FRACTIONAL_LOG2; 178 case IIO_CHAN_INFO_OFFSET: 179 if (st->range == AD7266_RANGE_2VREF && 180 st->mode != AD7266_MODE_DIFF) 181 *val = 2048; 182 else 183 *val = 0; 184 return IIO_VAL_INT; 185 } 186 return -EINVAL; 187 } 188 189 #define AD7266_CHAN(_chan, _sign) { \ 190 .type = IIO_VOLTAGE, \ 191 .indexed = 1, \ 192 .channel = (_chan), \ 193 .address = (_chan), \ 194 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 195 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 196 | BIT(IIO_CHAN_INFO_OFFSET), \ 197 .scan_index = (_chan), \ 198 .scan_type = { \ 199 .sign = (_sign), \ 200 .realbits = 12, \ 201 .storagebits = 16, \ 202 .shift = 2, \ 203 .endianness = IIO_BE, \ 204 }, \ 205 } 206 207 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \ 208 const struct iio_chan_spec ad7266_channels_##_name[] = { \ 209 AD7266_CHAN(0, (_sign)), \ 210 AD7266_CHAN(1, (_sign)), \ 211 AD7266_CHAN(2, (_sign)), \ 212 AD7266_CHAN(3, (_sign)), \ 213 AD7266_CHAN(4, (_sign)), \ 214 AD7266_CHAN(5, (_sign)), \ 215 AD7266_CHAN(6, (_sign)), \ 216 AD7266_CHAN(7, (_sign)), \ 217 AD7266_CHAN(8, (_sign)), \ 218 AD7266_CHAN(9, (_sign)), \ 219 AD7266_CHAN(10, (_sign)), \ 220 AD7266_CHAN(11, (_sign)), \ 221 IIO_CHAN_SOFT_TIMESTAMP(13), \ 222 } 223 224 #define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \ 225 const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \ 226 AD7266_CHAN(0, (_sign)), \ 227 AD7266_CHAN(1, (_sign)), \ 228 IIO_CHAN_SOFT_TIMESTAMP(2), \ 229 } 230 231 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u'); 232 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's'); 233 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u'); 234 static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's'); 235 236 #define AD7266_CHAN_DIFF(_chan, _sign) { \ 237 .type = IIO_VOLTAGE, \ 238 .indexed = 1, \ 239 .channel = (_chan) * 2, \ 240 .channel2 = (_chan) * 2 + 1, \ 241 .address = (_chan), \ 242 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 243 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \ 244 | BIT(IIO_CHAN_INFO_OFFSET), \ 245 .scan_index = (_chan), \ 246 .scan_type = { \ 247 .sign = _sign, \ 248 .realbits = 12, \ 249 .storagebits = 16, \ 250 .shift = 2, \ 251 .endianness = IIO_BE, \ 252 }, \ 253 .differential = 1, \ 254 } 255 256 #define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \ 257 const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \ 258 AD7266_CHAN_DIFF(0, (_sign)), \ 259 AD7266_CHAN_DIFF(1, (_sign)), \ 260 AD7266_CHAN_DIFF(2, (_sign)), \ 261 AD7266_CHAN_DIFF(3, (_sign)), \ 262 AD7266_CHAN_DIFF(4, (_sign)), \ 263 AD7266_CHAN_DIFF(5, (_sign)), \ 264 IIO_CHAN_SOFT_TIMESTAMP(6), \ 265 } 266 267 static AD7266_DECLARE_DIFF_CHANNELS(s, 's'); 268 static AD7266_DECLARE_DIFF_CHANNELS(u, 'u'); 269 270 #define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \ 271 const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \ 272 AD7266_CHAN_DIFF(0, (_sign)), \ 273 AD7266_CHAN_DIFF(1, (_sign)), \ 274 IIO_CHAN_SOFT_TIMESTAMP(2), \ 275 } 276 277 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's'); 278 static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u'); 279 280 static const struct iio_info ad7266_info = { 281 .read_raw = &ad7266_read_raw, 282 .update_scan_mode = &ad7266_update_scan_mode, 283 .driver_module = THIS_MODULE, 284 }; 285 286 static const unsigned long ad7266_available_scan_masks[] = { 287 0x003, 288 0x00c, 289 0x030, 290 0x0c0, 291 0x300, 292 0xc00, 293 0x000, 294 }; 295 296 static const unsigned long ad7266_available_scan_masks_diff[] = { 297 0x003, 298 0x00c, 299 0x030, 300 0x000, 301 }; 302 303 static const unsigned long ad7266_available_scan_masks_fixed[] = { 304 0x003, 305 0x000, 306 }; 307 308 struct ad7266_chan_info { 309 const struct iio_chan_spec *channels; 310 unsigned int num_channels; 311 const unsigned long *scan_masks; 312 }; 313 314 #define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \ 315 (((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0)) 316 317 static const struct ad7266_chan_info ad7266_chan_infos[] = { 318 [AD7266_CHAN_INFO_INDEX(0, 0, 0)] = { 319 .channels = ad7266_channels_u, 320 .num_channels = ARRAY_SIZE(ad7266_channels_u), 321 .scan_masks = ad7266_available_scan_masks, 322 }, 323 [AD7266_CHAN_INFO_INDEX(0, 0, 1)] = { 324 .channels = ad7266_channels_u_fixed, 325 .num_channels = ARRAY_SIZE(ad7266_channels_u_fixed), 326 .scan_masks = ad7266_available_scan_masks_fixed, 327 }, 328 [AD7266_CHAN_INFO_INDEX(0, 1, 0)] = { 329 .channels = ad7266_channels_s, 330 .num_channels = ARRAY_SIZE(ad7266_channels_s), 331 .scan_masks = ad7266_available_scan_masks, 332 }, 333 [AD7266_CHAN_INFO_INDEX(0, 1, 1)] = { 334 .channels = ad7266_channels_s_fixed, 335 .num_channels = ARRAY_SIZE(ad7266_channels_s_fixed), 336 .scan_masks = ad7266_available_scan_masks_fixed, 337 }, 338 [AD7266_CHAN_INFO_INDEX(1, 0, 0)] = { 339 .channels = ad7266_channels_diff_u, 340 .num_channels = ARRAY_SIZE(ad7266_channels_diff_u), 341 .scan_masks = ad7266_available_scan_masks_diff, 342 }, 343 [AD7266_CHAN_INFO_INDEX(1, 0, 1)] = { 344 .channels = ad7266_channels_diff_fixed_u, 345 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u), 346 .scan_masks = ad7266_available_scan_masks_fixed, 347 }, 348 [AD7266_CHAN_INFO_INDEX(1, 1, 0)] = { 349 .channels = ad7266_channels_diff_s, 350 .num_channels = ARRAY_SIZE(ad7266_channels_diff_s), 351 .scan_masks = ad7266_available_scan_masks_diff, 352 }, 353 [AD7266_CHAN_INFO_INDEX(1, 1, 1)] = { 354 .channels = ad7266_channels_diff_fixed_s, 355 .num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s), 356 .scan_masks = ad7266_available_scan_masks_fixed, 357 }, 358 }; 359 360 static void ad7266_init_channels(struct iio_dev *indio_dev) 361 { 362 struct ad7266_state *st = iio_priv(indio_dev); 363 bool is_differential, is_signed; 364 const struct ad7266_chan_info *chan_info; 365 int i; 366 367 is_differential = st->mode != AD7266_MODE_SINGLE_ENDED; 368 is_signed = (st->range == AD7266_RANGE_2VREF) | 369 (st->mode == AD7266_MODE_DIFF); 370 371 i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr); 372 chan_info = &ad7266_chan_infos[i]; 373 374 indio_dev->channels = chan_info->channels; 375 indio_dev->num_channels = chan_info->num_channels; 376 indio_dev->available_scan_masks = chan_info->scan_masks; 377 indio_dev->masklength = chan_info->num_channels - 1; 378 } 379 380 static const char * const ad7266_gpio_labels[] = { 381 "AD0", "AD1", "AD2", 382 }; 383 384 static int ad7266_probe(struct spi_device *spi) 385 { 386 struct ad7266_platform_data *pdata = spi->dev.platform_data; 387 struct iio_dev *indio_dev; 388 struct ad7266_state *st; 389 unsigned int i; 390 int ret; 391 392 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 393 if (indio_dev == NULL) 394 return -ENOMEM; 395 396 st = iio_priv(indio_dev); 397 398 st->reg = devm_regulator_get_optional(&spi->dev, "vref"); 399 if (!IS_ERR(st->reg)) { 400 ret = regulator_enable(st->reg); 401 if (ret) 402 return ret; 403 404 ret = regulator_get_voltage(st->reg); 405 if (ret < 0) 406 goto error_disable_reg; 407 408 st->vref_mv = ret / 1000; 409 } else { 410 /* Any other error indicates that the regulator does exist */ 411 if (PTR_ERR(st->reg) != -ENODEV) 412 return PTR_ERR(st->reg); 413 /* Use internal reference */ 414 st->vref_mv = 2500; 415 } 416 417 if (pdata) { 418 st->fixed_addr = pdata->fixed_addr; 419 st->mode = pdata->mode; 420 st->range = pdata->range; 421 422 if (!st->fixed_addr) { 423 for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) { 424 st->gpios[i].gpio = pdata->addr_gpios[i]; 425 st->gpios[i].flags = GPIOF_OUT_INIT_LOW; 426 st->gpios[i].label = ad7266_gpio_labels[i]; 427 } 428 ret = gpio_request_array(st->gpios, 429 ARRAY_SIZE(st->gpios)); 430 if (ret) 431 goto error_disable_reg; 432 } 433 } else { 434 st->fixed_addr = true; 435 st->range = AD7266_RANGE_VREF; 436 st->mode = AD7266_MODE_DIFF; 437 } 438 439 spi_set_drvdata(spi, indio_dev); 440 st->spi = spi; 441 442 indio_dev->dev.parent = &spi->dev; 443 indio_dev->dev.of_node = spi->dev.of_node; 444 indio_dev->name = spi_get_device_id(spi)->name; 445 indio_dev->modes = INDIO_DIRECT_MODE; 446 indio_dev->info = &ad7266_info; 447 448 ad7266_init_channels(indio_dev); 449 450 /* wakeup */ 451 st->single_xfer[0].rx_buf = &st->data.sample[0]; 452 st->single_xfer[0].len = 2; 453 st->single_xfer[0].cs_change = 1; 454 /* conversion */ 455 st->single_xfer[1].rx_buf = st->data.sample; 456 st->single_xfer[1].len = 4; 457 st->single_xfer[1].cs_change = 1; 458 /* powerdown */ 459 st->single_xfer[2].tx_buf = &st->data.sample[0]; 460 st->single_xfer[2].len = 1; 461 462 spi_message_init(&st->single_msg); 463 spi_message_add_tail(&st->single_xfer[0], &st->single_msg); 464 spi_message_add_tail(&st->single_xfer[1], &st->single_msg); 465 spi_message_add_tail(&st->single_xfer[2], &st->single_msg); 466 467 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time, 468 &ad7266_trigger_handler, &iio_triggered_buffer_setup_ops); 469 if (ret) 470 goto error_free_gpios; 471 472 ret = iio_device_register(indio_dev); 473 if (ret) 474 goto error_buffer_cleanup; 475 476 return 0; 477 478 error_buffer_cleanup: 479 iio_triggered_buffer_cleanup(indio_dev); 480 error_free_gpios: 481 if (!st->fixed_addr) 482 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); 483 error_disable_reg: 484 if (!IS_ERR(st->reg)) 485 regulator_disable(st->reg); 486 487 return ret; 488 } 489 490 static int ad7266_remove(struct spi_device *spi) 491 { 492 struct iio_dev *indio_dev = spi_get_drvdata(spi); 493 struct ad7266_state *st = iio_priv(indio_dev); 494 495 iio_device_unregister(indio_dev); 496 iio_triggered_buffer_cleanup(indio_dev); 497 if (!st->fixed_addr) 498 gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios)); 499 if (!IS_ERR(st->reg)) 500 regulator_disable(st->reg); 501 502 return 0; 503 } 504 505 static const struct spi_device_id ad7266_id[] = { 506 {"ad7265", 0}, 507 {"ad7266", 0}, 508 { } 509 }; 510 MODULE_DEVICE_TABLE(spi, ad7266_id); 511 512 static struct spi_driver ad7266_driver = { 513 .driver = { 514 .name = "ad7266", 515 }, 516 .probe = ad7266_probe, 517 .remove = ad7266_remove, 518 .id_table = ad7266_id, 519 }; 520 module_spi_driver(ad7266_driver); 521 522 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 523 MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC"); 524 MODULE_LICENSE("GPL v2"); 525