1 /* 2 * ADS7846 based touchscreen and sensor driver 3 * 4 * Copyright (c) 2005 David Brownell 5 * Copyright (c) 2006 Nokia Corporation 6 * Various changes: Imre Deak <imre.deak@nokia.com> 7 * 8 * Using code from: 9 * - corgi_ts.c 10 * Copyright (C) 2004-2005 Richard Purdie 11 * - omap_ts.[hc], ads7846.h, ts_osk.c 12 * Copyright (C) 2002 MontaVista Software 13 * Copyright (C) 2004 Texas Instruments 14 * Copyright (C) 2005 Dirk Behme 15 * 16 * This program is free software; you can redistribute it and/or modify 17 * it under the terms of the GNU General Public License version 2 as 18 * published by the Free Software Foundation. 19 */ 20 #include <linux/types.h> 21 #include <linux/hwmon.h> 22 #include <linux/init.h> 23 #include <linux/err.h> 24 #include <linux/sched.h> 25 #include <linux/delay.h> 26 #include <linux/input.h> 27 #include <linux/interrupt.h> 28 #include <linux/slab.h> 29 #include <linux/pm.h> 30 #include <linux/gpio.h> 31 #include <linux/spi/spi.h> 32 #include <linux/spi/ads7846.h> 33 #include <linux/regulator/consumer.h> 34 #include <linux/module.h> 35 #include <asm/irq.h> 36 37 /* 38 * This code has been heavily tested on a Nokia 770, and lightly 39 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz). 40 * TSC2046 is just newer ads7846 silicon. 41 * Support for ads7843 tested on Atmel at91sam926x-EK. 42 * Support for ads7845 has only been stubbed in. 43 * Support for Analog Devices AD7873 and AD7843 tested. 44 * 45 * IRQ handling needs a workaround because of a shortcoming in handling 46 * edge triggered IRQs on some platforms like the OMAP1/2. These 47 * platforms don't handle the ARM lazy IRQ disabling properly, thus we 48 * have to maintain our own SW IRQ disabled status. This should be 49 * removed as soon as the affected platform's IRQ handling is fixed. 50 * 51 * App note sbaa036 talks in more detail about accurate sampling... 52 * that ought to help in situations like LCDs inducing noise (which 53 * can also be helped by using synch signals) and more generally. 54 * This driver tries to utilize the measures described in the app 55 * note. The strength of filtering can be set in the board-* specific 56 * files. 57 */ 58 59 #define TS_POLL_DELAY 1 /* ms delay before the first sample */ 60 #define TS_POLL_PERIOD 5 /* ms delay between samples */ 61 62 /* this driver doesn't aim at the peak continuous sample rate */ 63 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */) 64 65 struct ts_event { 66 /* 67 * For portability, we can't read 12 bit values using SPI (which 68 * would make the controller deliver them as native byte order u16 69 * with msbs zeroed). Instead, we read them as two 8-bit values, 70 * *** WHICH NEED BYTESWAPPING *** and range adjustment. 71 */ 72 u16 x; 73 u16 y; 74 u16 z1, z2; 75 bool ignore; 76 u8 x_buf[3]; 77 u8 y_buf[3]; 78 }; 79 80 /* 81 * We allocate this separately to avoid cache line sharing issues when 82 * driver is used with DMA-based SPI controllers (like atmel_spi) on 83 * systems where main memory is not DMA-coherent (most non-x86 boards). 84 */ 85 struct ads7846_packet { 86 u8 read_x, read_y, read_z1, read_z2, pwrdown; 87 u16 dummy; /* for the pwrdown read */ 88 struct ts_event tc; 89 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */ 90 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3]; 91 }; 92 93 struct ads7846 { 94 struct input_dev *input; 95 char phys[32]; 96 char name[32]; 97 98 struct spi_device *spi; 99 struct regulator *reg; 100 101 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 102 struct attribute_group *attr_group; 103 struct device *hwmon; 104 #endif 105 106 u16 model; 107 u16 vref_mv; 108 u16 vref_delay_usecs; 109 u16 x_plate_ohms; 110 u16 pressure_max; 111 112 bool swap_xy; 113 bool use_internal; 114 115 struct ads7846_packet *packet; 116 117 struct spi_transfer xfer[18]; 118 struct spi_message msg[5]; 119 int msg_count; 120 wait_queue_head_t wait; 121 122 bool pendown; 123 124 int read_cnt; 125 int read_rep; 126 int last_read; 127 128 u16 debounce_max; 129 u16 debounce_tol; 130 u16 debounce_rep; 131 132 u16 penirq_recheck_delay_usecs; 133 134 struct mutex lock; 135 bool stopped; /* P: lock */ 136 bool disabled; /* P: lock */ 137 bool suspended; /* P: lock */ 138 139 int (*filter)(void *data, int data_idx, int *val); 140 void *filter_data; 141 void (*filter_cleanup)(void *data); 142 int (*get_pendown_state)(void); 143 int gpio_pendown; 144 145 void (*wait_for_sync)(void); 146 }; 147 148 /* leave chip selected when we're done, for quicker re-select? */ 149 #if 0 150 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) 151 #else 152 #define CS_CHANGE(xfer) ((xfer).cs_change = 0) 153 #endif 154 155 /*--------------------------------------------------------------------------*/ 156 157 /* The ADS7846 has touchscreen and other sensors. 158 * Earlier ads784x chips are somewhat compatible. 159 */ 160 #define ADS_START (1 << 7) 161 #define ADS_A2A1A0_d_y (1 << 4) /* differential */ 162 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ 163 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ 164 #define ADS_A2A1A0_d_x (5 << 4) /* differential */ 165 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ 166 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ 167 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ 168 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ 169 #define ADS_8_BIT (1 << 3) 170 #define ADS_12_BIT (0 << 3) 171 #define ADS_SER (1 << 2) /* non-differential */ 172 #define ADS_DFR (0 << 2) /* differential */ 173 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */ 174 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ 175 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ 176 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ 177 178 #define MAX_12BIT ((1<<12)-1) 179 180 /* leave ADC powered up (disables penirq) between differential samples */ 181 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ 182 | ADS_12_BIT | ADS_DFR | \ 183 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) 184 185 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) 186 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) 187 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) 188 189 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) 190 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ 191 192 /* single-ended samples need to first power up reference voltage; 193 * we leave both ADC and VREF powered 194 */ 195 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ 196 | ADS_12_BIT | ADS_SER) 197 198 #define REF_ON (READ_12BIT_DFR(x, 1, 1)) 199 #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) 200 201 /* Must be called with ts->lock held */ 202 static void ads7846_stop(struct ads7846 *ts) 203 { 204 if (!ts->disabled && !ts->suspended) { 205 /* Signal IRQ thread to stop polling and disable the handler. */ 206 ts->stopped = true; 207 mb(); 208 wake_up(&ts->wait); 209 disable_irq(ts->spi->irq); 210 } 211 } 212 213 /* Must be called with ts->lock held */ 214 static void ads7846_restart(struct ads7846 *ts) 215 { 216 if (!ts->disabled && !ts->suspended) { 217 /* Tell IRQ thread that it may poll the device. */ 218 ts->stopped = false; 219 mb(); 220 enable_irq(ts->spi->irq); 221 } 222 } 223 224 /* Must be called with ts->lock held */ 225 static void __ads7846_disable(struct ads7846 *ts) 226 { 227 ads7846_stop(ts); 228 regulator_disable(ts->reg); 229 230 /* 231 * We know the chip's in low power mode since we always 232 * leave it that way after every request 233 */ 234 } 235 236 /* Must be called with ts->lock held */ 237 static void __ads7846_enable(struct ads7846 *ts) 238 { 239 regulator_enable(ts->reg); 240 ads7846_restart(ts); 241 } 242 243 static void ads7846_disable(struct ads7846 *ts) 244 { 245 mutex_lock(&ts->lock); 246 247 if (!ts->disabled) { 248 249 if (!ts->suspended) 250 __ads7846_disable(ts); 251 252 ts->disabled = true; 253 } 254 255 mutex_unlock(&ts->lock); 256 } 257 258 static void ads7846_enable(struct ads7846 *ts) 259 { 260 mutex_lock(&ts->lock); 261 262 if (ts->disabled) { 263 264 ts->disabled = false; 265 266 if (!ts->suspended) 267 __ads7846_enable(ts); 268 } 269 270 mutex_unlock(&ts->lock); 271 } 272 273 /*--------------------------------------------------------------------------*/ 274 275 /* 276 * Non-touchscreen sensors only use single-ended conversions. 277 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; 278 * ads7846 lets that pin be unconnected, to use internal vREF. 279 */ 280 281 struct ser_req { 282 u8 ref_on; 283 u8 command; 284 u8 ref_off; 285 u16 scratch; 286 struct spi_message msg; 287 struct spi_transfer xfer[6]; 288 /* 289 * DMA (thus cache coherency maintenance) requires the 290 * transfer buffers to live in their own cache lines. 291 */ 292 __be16 sample ____cacheline_aligned; 293 }; 294 295 struct ads7845_ser_req { 296 u8 command[3]; 297 struct spi_message msg; 298 struct spi_transfer xfer[2]; 299 /* 300 * DMA (thus cache coherency maintenance) requires the 301 * transfer buffers to live in their own cache lines. 302 */ 303 u8 sample[3] ____cacheline_aligned; 304 }; 305 306 static int ads7846_read12_ser(struct device *dev, unsigned command) 307 { 308 struct spi_device *spi = to_spi_device(dev); 309 struct ads7846 *ts = dev_get_drvdata(dev); 310 struct ser_req *req; 311 int status; 312 313 req = kzalloc(sizeof *req, GFP_KERNEL); 314 if (!req) 315 return -ENOMEM; 316 317 spi_message_init(&req->msg); 318 319 /* maybe turn on internal vREF, and let it settle */ 320 if (ts->use_internal) { 321 req->ref_on = REF_ON; 322 req->xfer[0].tx_buf = &req->ref_on; 323 req->xfer[0].len = 1; 324 spi_message_add_tail(&req->xfer[0], &req->msg); 325 326 req->xfer[1].rx_buf = &req->scratch; 327 req->xfer[1].len = 2; 328 329 /* for 1uF, settle for 800 usec; no cap, 100 usec. */ 330 req->xfer[1].delay_usecs = ts->vref_delay_usecs; 331 spi_message_add_tail(&req->xfer[1], &req->msg); 332 333 /* Enable reference voltage */ 334 command |= ADS_PD10_REF_ON; 335 } 336 337 /* Enable ADC in every case */ 338 command |= ADS_PD10_ADC_ON; 339 340 /* take sample */ 341 req->command = (u8) command; 342 req->xfer[2].tx_buf = &req->command; 343 req->xfer[2].len = 1; 344 spi_message_add_tail(&req->xfer[2], &req->msg); 345 346 req->xfer[3].rx_buf = &req->sample; 347 req->xfer[3].len = 2; 348 spi_message_add_tail(&req->xfer[3], &req->msg); 349 350 /* REVISIT: take a few more samples, and compare ... */ 351 352 /* converter in low power mode & enable PENIRQ */ 353 req->ref_off = PWRDOWN; 354 req->xfer[4].tx_buf = &req->ref_off; 355 req->xfer[4].len = 1; 356 spi_message_add_tail(&req->xfer[4], &req->msg); 357 358 req->xfer[5].rx_buf = &req->scratch; 359 req->xfer[5].len = 2; 360 CS_CHANGE(req->xfer[5]); 361 spi_message_add_tail(&req->xfer[5], &req->msg); 362 363 mutex_lock(&ts->lock); 364 ads7846_stop(ts); 365 status = spi_sync(spi, &req->msg); 366 ads7846_restart(ts); 367 mutex_unlock(&ts->lock); 368 369 if (status == 0) { 370 /* on-wire is a must-ignore bit, a BE12 value, then padding */ 371 status = be16_to_cpu(req->sample); 372 status = status >> 3; 373 status &= 0x0fff; 374 } 375 376 kfree(req); 377 return status; 378 } 379 380 static int ads7845_read12_ser(struct device *dev, unsigned command) 381 { 382 struct spi_device *spi = to_spi_device(dev); 383 struct ads7846 *ts = dev_get_drvdata(dev); 384 struct ads7845_ser_req *req; 385 int status; 386 387 req = kzalloc(sizeof *req, GFP_KERNEL); 388 if (!req) 389 return -ENOMEM; 390 391 spi_message_init(&req->msg); 392 393 req->command[0] = (u8) command; 394 req->xfer[0].tx_buf = req->command; 395 req->xfer[0].rx_buf = req->sample; 396 req->xfer[0].len = 3; 397 spi_message_add_tail(&req->xfer[0], &req->msg); 398 399 mutex_lock(&ts->lock); 400 ads7846_stop(ts); 401 status = spi_sync(spi, &req->msg); 402 ads7846_restart(ts); 403 mutex_unlock(&ts->lock); 404 405 if (status == 0) { 406 /* BE12 value, then padding */ 407 status = be16_to_cpu(*((u16 *)&req->sample[1])); 408 status = status >> 3; 409 status &= 0x0fff; 410 } 411 412 kfree(req); 413 return status; 414 } 415 416 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 417 418 #define SHOW(name, var, adjust) static ssize_t \ 419 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 420 { \ 421 struct ads7846 *ts = dev_get_drvdata(dev); \ 422 ssize_t v = ads7846_read12_ser(dev, \ 423 READ_12BIT_SER(var)); \ 424 if (v < 0) \ 425 return v; \ 426 return sprintf(buf, "%u\n", adjust(ts, v)); \ 427 } \ 428 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); 429 430 431 /* Sysfs conventions report temperatures in millidegrees Celsius. 432 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high 433 * accuracy scheme without calibration data. For now we won't try either; 434 * userspace sees raw sensor values, and must scale/calibrate appropriately. 435 */ 436 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) 437 { 438 return v; 439 } 440 441 SHOW(temp0, temp0, null_adjust) /* temp1_input */ 442 SHOW(temp1, temp1, null_adjust) /* temp2_input */ 443 444 445 /* sysfs conventions report voltages in millivolts. We can convert voltages 446 * if we know vREF. userspace may need to scale vAUX to match the board's 447 * external resistors; we assume that vBATT only uses the internal ones. 448 */ 449 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 450 { 451 unsigned retval = v; 452 453 /* external resistors may scale vAUX into 0..vREF */ 454 retval *= ts->vref_mv; 455 retval = retval >> 12; 456 457 return retval; 458 } 459 460 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) 461 { 462 unsigned retval = vaux_adjust(ts, v); 463 464 /* ads7846 has a resistor ladder to scale this signal down */ 465 if (ts->model == 7846) 466 retval *= 4; 467 468 return retval; 469 } 470 471 SHOW(in0_input, vaux, vaux_adjust) 472 SHOW(in1_input, vbatt, vbatt_adjust) 473 474 static struct attribute *ads7846_attributes[] = { 475 &dev_attr_temp0.attr, 476 &dev_attr_temp1.attr, 477 &dev_attr_in0_input.attr, 478 &dev_attr_in1_input.attr, 479 NULL, 480 }; 481 482 static struct attribute_group ads7846_attr_group = { 483 .attrs = ads7846_attributes, 484 }; 485 486 static struct attribute *ads7843_attributes[] = { 487 &dev_attr_in0_input.attr, 488 &dev_attr_in1_input.attr, 489 NULL, 490 }; 491 492 static struct attribute_group ads7843_attr_group = { 493 .attrs = ads7843_attributes, 494 }; 495 496 static struct attribute *ads7845_attributes[] = { 497 &dev_attr_in0_input.attr, 498 NULL, 499 }; 500 501 static struct attribute_group ads7845_attr_group = { 502 .attrs = ads7845_attributes, 503 }; 504 505 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 506 { 507 struct device *hwmon; 508 int err; 509 510 /* hwmon sensors need a reference voltage */ 511 switch (ts->model) { 512 case 7846: 513 if (!ts->vref_mv) { 514 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); 515 ts->vref_mv = 2500; 516 ts->use_internal = true; 517 } 518 break; 519 case 7845: 520 case 7843: 521 if (!ts->vref_mv) { 522 dev_warn(&spi->dev, 523 "external vREF for ADS%d not specified\n", 524 ts->model); 525 return 0; 526 } 527 break; 528 } 529 530 /* different chips have different sensor groups */ 531 switch (ts->model) { 532 case 7846: 533 ts->attr_group = &ads7846_attr_group; 534 break; 535 case 7845: 536 ts->attr_group = &ads7845_attr_group; 537 break; 538 case 7843: 539 ts->attr_group = &ads7843_attr_group; 540 break; 541 default: 542 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); 543 return 0; 544 } 545 546 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); 547 if (err) 548 return err; 549 550 hwmon = hwmon_device_register(&spi->dev); 551 if (IS_ERR(hwmon)) { 552 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 553 return PTR_ERR(hwmon); 554 } 555 556 ts->hwmon = hwmon; 557 return 0; 558 } 559 560 static void ads784x_hwmon_unregister(struct spi_device *spi, 561 struct ads7846 *ts) 562 { 563 if (ts->hwmon) { 564 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 565 hwmon_device_unregister(ts->hwmon); 566 } 567 } 568 569 #else 570 static inline int ads784x_hwmon_register(struct spi_device *spi, 571 struct ads7846 *ts) 572 { 573 return 0; 574 } 575 576 static inline void ads784x_hwmon_unregister(struct spi_device *spi, 577 struct ads7846 *ts) 578 { 579 } 580 #endif 581 582 static ssize_t ads7846_pen_down_show(struct device *dev, 583 struct device_attribute *attr, char *buf) 584 { 585 struct ads7846 *ts = dev_get_drvdata(dev); 586 587 return sprintf(buf, "%u\n", ts->pendown); 588 } 589 590 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); 591 592 static ssize_t ads7846_disable_show(struct device *dev, 593 struct device_attribute *attr, char *buf) 594 { 595 struct ads7846 *ts = dev_get_drvdata(dev); 596 597 return sprintf(buf, "%u\n", ts->disabled); 598 } 599 600 static ssize_t ads7846_disable_store(struct device *dev, 601 struct device_attribute *attr, 602 const char *buf, size_t count) 603 { 604 struct ads7846 *ts = dev_get_drvdata(dev); 605 unsigned long i; 606 607 if (strict_strtoul(buf, 10, &i)) 608 return -EINVAL; 609 610 if (i) 611 ads7846_disable(ts); 612 else 613 ads7846_enable(ts); 614 615 return count; 616 } 617 618 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); 619 620 static struct attribute *ads784x_attributes[] = { 621 &dev_attr_pen_down.attr, 622 &dev_attr_disable.attr, 623 NULL, 624 }; 625 626 static struct attribute_group ads784x_attr_group = { 627 .attrs = ads784x_attributes, 628 }; 629 630 /*--------------------------------------------------------------------------*/ 631 632 static int get_pendown_state(struct ads7846 *ts) 633 { 634 if (ts->get_pendown_state) 635 return ts->get_pendown_state(); 636 637 return !gpio_get_value(ts->gpio_pendown); 638 } 639 640 static void null_wait_for_sync(void) 641 { 642 } 643 644 static int ads7846_debounce_filter(void *ads, int data_idx, int *val) 645 { 646 struct ads7846 *ts = ads; 647 648 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { 649 /* Start over collecting consistent readings. */ 650 ts->read_rep = 0; 651 /* 652 * Repeat it, if this was the first read or the read 653 * wasn't consistent enough. 654 */ 655 if (ts->read_cnt < ts->debounce_max) { 656 ts->last_read = *val; 657 ts->read_cnt++; 658 return ADS7846_FILTER_REPEAT; 659 } else { 660 /* 661 * Maximum number of debouncing reached and still 662 * not enough number of consistent readings. Abort 663 * the whole sample, repeat it in the next sampling 664 * period. 665 */ 666 ts->read_cnt = 0; 667 return ADS7846_FILTER_IGNORE; 668 } 669 } else { 670 if (++ts->read_rep > ts->debounce_rep) { 671 /* 672 * Got a good reading for this coordinate, 673 * go for the next one. 674 */ 675 ts->read_cnt = 0; 676 ts->read_rep = 0; 677 return ADS7846_FILTER_OK; 678 } else { 679 /* Read more values that are consistent. */ 680 ts->read_cnt++; 681 return ADS7846_FILTER_REPEAT; 682 } 683 } 684 } 685 686 static int ads7846_no_filter(void *ads, int data_idx, int *val) 687 { 688 return ADS7846_FILTER_OK; 689 } 690 691 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m) 692 { 693 struct spi_transfer *t = 694 list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 695 696 if (ts->model == 7845) { 697 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3; 698 } else { 699 /* 700 * adjust: on-wire is a must-ignore bit, a BE12 value, then 701 * padding; built from two 8 bit values written msb-first. 702 */ 703 return be16_to_cpup((__be16 *)t->rx_buf) >> 3; 704 } 705 } 706 707 static void ads7846_update_value(struct spi_message *m, int val) 708 { 709 struct spi_transfer *t = 710 list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 711 712 *(u16 *)t->rx_buf = val; 713 } 714 715 static void ads7846_read_state(struct ads7846 *ts) 716 { 717 struct ads7846_packet *packet = ts->packet; 718 struct spi_message *m; 719 int msg_idx = 0; 720 int val; 721 int action; 722 int error; 723 724 while (msg_idx < ts->msg_count) { 725 726 ts->wait_for_sync(); 727 728 m = &ts->msg[msg_idx]; 729 error = spi_sync(ts->spi, m); 730 if (error) { 731 dev_err(&ts->spi->dev, "spi_async --> %d\n", error); 732 packet->tc.ignore = true; 733 return; 734 } 735 736 /* 737 * Last message is power down request, no need to convert 738 * or filter the value. 739 */ 740 if (msg_idx < ts->msg_count - 1) { 741 742 val = ads7846_get_value(ts, m); 743 744 action = ts->filter(ts->filter_data, msg_idx, &val); 745 switch (action) { 746 case ADS7846_FILTER_REPEAT: 747 continue; 748 749 case ADS7846_FILTER_IGNORE: 750 packet->tc.ignore = true; 751 msg_idx = ts->msg_count - 1; 752 continue; 753 754 case ADS7846_FILTER_OK: 755 ads7846_update_value(m, val); 756 packet->tc.ignore = false; 757 msg_idx++; 758 break; 759 760 default: 761 BUG(); 762 } 763 } else { 764 msg_idx++; 765 } 766 } 767 } 768 769 static void ads7846_report_state(struct ads7846 *ts) 770 { 771 struct ads7846_packet *packet = ts->packet; 772 unsigned int Rt; 773 u16 x, y, z1, z2; 774 775 /* 776 * ads7846_get_value() does in-place conversion (including byte swap) 777 * from on-the-wire format as part of debouncing to get stable 778 * readings. 779 */ 780 if (ts->model == 7845) { 781 x = *(u16 *)packet->tc.x_buf; 782 y = *(u16 *)packet->tc.y_buf; 783 z1 = 0; 784 z2 = 0; 785 } else { 786 x = packet->tc.x; 787 y = packet->tc.y; 788 z1 = packet->tc.z1; 789 z2 = packet->tc.z2; 790 } 791 792 /* range filtering */ 793 if (x == MAX_12BIT) 794 x = 0; 795 796 if (ts->model == 7843) { 797 Rt = ts->pressure_max / 2; 798 } else if (ts->model == 7845) { 799 if (get_pendown_state(ts)) 800 Rt = ts->pressure_max / 2; 801 else 802 Rt = 0; 803 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt); 804 } else if (likely(x && z1)) { 805 /* compute touch pressure resistance using equation #2 */ 806 Rt = z2; 807 Rt -= z1; 808 Rt *= x; 809 Rt *= ts->x_plate_ohms; 810 Rt /= z1; 811 Rt = (Rt + 2047) >> 12; 812 } else { 813 Rt = 0; 814 } 815 816 /* 817 * Sample found inconsistent by debouncing or pressure is beyond 818 * the maximum. Don't report it to user space, repeat at least 819 * once more the measurement 820 */ 821 if (packet->tc.ignore || Rt > ts->pressure_max) { 822 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n", 823 packet->tc.ignore, Rt); 824 return; 825 } 826 827 /* 828 * Maybe check the pendown state before reporting. This discards 829 * false readings when the pen is lifted. 830 */ 831 if (ts->penirq_recheck_delay_usecs) { 832 udelay(ts->penirq_recheck_delay_usecs); 833 if (!get_pendown_state(ts)) 834 Rt = 0; 835 } 836 837 /* 838 * NOTE: We can't rely on the pressure to determine the pen down 839 * state, even this controller has a pressure sensor. The pressure 840 * value can fluctuate for quite a while after lifting the pen and 841 * in some cases may not even settle at the expected value. 842 * 843 * The only safe way to check for the pen up condition is in the 844 * timer by reading the pen signal state (it's a GPIO _and_ IRQ). 845 */ 846 if (Rt) { 847 struct input_dev *input = ts->input; 848 849 if (ts->swap_xy) 850 swap(x, y); 851 852 if (!ts->pendown) { 853 input_report_key(input, BTN_TOUCH, 1); 854 ts->pendown = true; 855 dev_vdbg(&ts->spi->dev, "DOWN\n"); 856 } 857 858 input_report_abs(input, ABS_X, x); 859 input_report_abs(input, ABS_Y, y); 860 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt); 861 862 input_sync(input); 863 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); 864 } 865 } 866 867 static irqreturn_t ads7846_hard_irq(int irq, void *handle) 868 { 869 struct ads7846 *ts = handle; 870 871 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED; 872 } 873 874 875 static irqreturn_t ads7846_irq(int irq, void *handle) 876 { 877 struct ads7846 *ts = handle; 878 879 /* Start with a small delay before checking pendown state */ 880 msleep(TS_POLL_DELAY); 881 882 while (!ts->stopped && get_pendown_state(ts)) { 883 884 /* pen is down, continue with the measurement */ 885 ads7846_read_state(ts); 886 887 if (!ts->stopped) 888 ads7846_report_state(ts); 889 890 wait_event_timeout(ts->wait, ts->stopped, 891 msecs_to_jiffies(TS_POLL_PERIOD)); 892 } 893 894 if (ts->pendown) { 895 struct input_dev *input = ts->input; 896 897 input_report_key(input, BTN_TOUCH, 0); 898 input_report_abs(input, ABS_PRESSURE, 0); 899 input_sync(input); 900 901 ts->pendown = false; 902 dev_vdbg(&ts->spi->dev, "UP\n"); 903 } 904 905 return IRQ_HANDLED; 906 } 907 908 #ifdef CONFIG_PM_SLEEP 909 static int ads7846_suspend(struct device *dev) 910 { 911 struct ads7846 *ts = dev_get_drvdata(dev); 912 913 mutex_lock(&ts->lock); 914 915 if (!ts->suspended) { 916 917 if (!ts->disabled) 918 __ads7846_disable(ts); 919 920 if (device_may_wakeup(&ts->spi->dev)) 921 enable_irq_wake(ts->spi->irq); 922 923 ts->suspended = true; 924 } 925 926 mutex_unlock(&ts->lock); 927 928 return 0; 929 } 930 931 static int ads7846_resume(struct device *dev) 932 { 933 struct ads7846 *ts = dev_get_drvdata(dev); 934 935 mutex_lock(&ts->lock); 936 937 if (ts->suspended) { 938 939 ts->suspended = false; 940 941 if (device_may_wakeup(&ts->spi->dev)) 942 disable_irq_wake(ts->spi->irq); 943 944 if (!ts->disabled) 945 __ads7846_enable(ts); 946 } 947 948 mutex_unlock(&ts->lock); 949 950 return 0; 951 } 952 #endif 953 954 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume); 955 956 static int __devinit ads7846_setup_pendown(struct spi_device *spi, struct ads7846 *ts) 957 { 958 struct ads7846_platform_data *pdata = spi->dev.platform_data; 959 int err; 960 961 /* 962 * REVISIT when the irq can be triggered active-low, or if for some 963 * reason the touchscreen isn't hooked up, we don't need to access 964 * the pendown state. 965 */ 966 967 if (pdata->get_pendown_state) { 968 ts->get_pendown_state = pdata->get_pendown_state; 969 } else if (gpio_is_valid(pdata->gpio_pendown)) { 970 971 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN, 972 "ads7846_pendown"); 973 if (err) { 974 dev_err(&spi->dev, 975 "failed to request/setup pendown GPIO%d: %d\n", 976 pdata->gpio_pendown, err); 977 return err; 978 } 979 980 ts->gpio_pendown = pdata->gpio_pendown; 981 982 } else { 983 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n"); 984 return -EINVAL; 985 } 986 987 return 0; 988 } 989 990 /* 991 * Set up the transfers to read touchscreen state; this assumes we 992 * use formula #2 for pressure, not #3. 993 */ 994 static void __devinit ads7846_setup_spi_msg(struct ads7846 *ts, 995 const struct ads7846_platform_data *pdata) 996 { 997 struct spi_message *m = &ts->msg[0]; 998 struct spi_transfer *x = ts->xfer; 999 struct ads7846_packet *packet = ts->packet; 1000 int vref = pdata->keep_vref_on; 1001 1002 if (ts->model == 7873) { 1003 /* 1004 * The AD7873 is almost identical to the ADS7846 1005 * keep VREF off during differential/ratiometric 1006 * conversion modes. 1007 */ 1008 ts->model = 7846; 1009 vref = 0; 1010 } 1011 1012 ts->msg_count = 1; 1013 spi_message_init(m); 1014 m->context = ts; 1015 1016 if (ts->model == 7845) { 1017 packet->read_y_cmd[0] = READ_Y(vref); 1018 packet->read_y_cmd[1] = 0; 1019 packet->read_y_cmd[2] = 0; 1020 x->tx_buf = &packet->read_y_cmd[0]; 1021 x->rx_buf = &packet->tc.y_buf[0]; 1022 x->len = 3; 1023 spi_message_add_tail(x, m); 1024 } else { 1025 /* y- still on; turn on only y+ (and ADC) */ 1026 packet->read_y = READ_Y(vref); 1027 x->tx_buf = &packet->read_y; 1028 x->len = 1; 1029 spi_message_add_tail(x, m); 1030 1031 x++; 1032 x->rx_buf = &packet->tc.y; 1033 x->len = 2; 1034 spi_message_add_tail(x, m); 1035 } 1036 1037 /* 1038 * The first sample after switching drivers can be low quality; 1039 * optionally discard it, using a second one after the signals 1040 * have had enough time to stabilize. 1041 */ 1042 if (pdata->settle_delay_usecs) { 1043 x->delay_usecs = pdata->settle_delay_usecs; 1044 1045 x++; 1046 x->tx_buf = &packet->read_y; 1047 x->len = 1; 1048 spi_message_add_tail(x, m); 1049 1050 x++; 1051 x->rx_buf = &packet->tc.y; 1052 x->len = 2; 1053 spi_message_add_tail(x, m); 1054 } 1055 1056 ts->msg_count++; 1057 m++; 1058 spi_message_init(m); 1059 m->context = ts; 1060 1061 if (ts->model == 7845) { 1062 x++; 1063 packet->read_x_cmd[0] = READ_X(vref); 1064 packet->read_x_cmd[1] = 0; 1065 packet->read_x_cmd[2] = 0; 1066 x->tx_buf = &packet->read_x_cmd[0]; 1067 x->rx_buf = &packet->tc.x_buf[0]; 1068 x->len = 3; 1069 spi_message_add_tail(x, m); 1070 } else { 1071 /* turn y- off, x+ on, then leave in lowpower */ 1072 x++; 1073 packet->read_x = READ_X(vref); 1074 x->tx_buf = &packet->read_x; 1075 x->len = 1; 1076 spi_message_add_tail(x, m); 1077 1078 x++; 1079 x->rx_buf = &packet->tc.x; 1080 x->len = 2; 1081 spi_message_add_tail(x, m); 1082 } 1083 1084 /* ... maybe discard first sample ... */ 1085 if (pdata->settle_delay_usecs) { 1086 x->delay_usecs = pdata->settle_delay_usecs; 1087 1088 x++; 1089 x->tx_buf = &packet->read_x; 1090 x->len = 1; 1091 spi_message_add_tail(x, m); 1092 1093 x++; 1094 x->rx_buf = &packet->tc.x; 1095 x->len = 2; 1096 spi_message_add_tail(x, m); 1097 } 1098 1099 /* turn y+ off, x- on; we'll use formula #2 */ 1100 if (ts->model == 7846) { 1101 ts->msg_count++; 1102 m++; 1103 spi_message_init(m); 1104 m->context = ts; 1105 1106 x++; 1107 packet->read_z1 = READ_Z1(vref); 1108 x->tx_buf = &packet->read_z1; 1109 x->len = 1; 1110 spi_message_add_tail(x, m); 1111 1112 x++; 1113 x->rx_buf = &packet->tc.z1; 1114 x->len = 2; 1115 spi_message_add_tail(x, m); 1116 1117 /* ... maybe discard first sample ... */ 1118 if (pdata->settle_delay_usecs) { 1119 x->delay_usecs = pdata->settle_delay_usecs; 1120 1121 x++; 1122 x->tx_buf = &packet->read_z1; 1123 x->len = 1; 1124 spi_message_add_tail(x, m); 1125 1126 x++; 1127 x->rx_buf = &packet->tc.z1; 1128 x->len = 2; 1129 spi_message_add_tail(x, m); 1130 } 1131 1132 ts->msg_count++; 1133 m++; 1134 spi_message_init(m); 1135 m->context = ts; 1136 1137 x++; 1138 packet->read_z2 = READ_Z2(vref); 1139 x->tx_buf = &packet->read_z2; 1140 x->len = 1; 1141 spi_message_add_tail(x, m); 1142 1143 x++; 1144 x->rx_buf = &packet->tc.z2; 1145 x->len = 2; 1146 spi_message_add_tail(x, m); 1147 1148 /* ... maybe discard first sample ... */ 1149 if (pdata->settle_delay_usecs) { 1150 x->delay_usecs = pdata->settle_delay_usecs; 1151 1152 x++; 1153 x->tx_buf = &packet->read_z2; 1154 x->len = 1; 1155 spi_message_add_tail(x, m); 1156 1157 x++; 1158 x->rx_buf = &packet->tc.z2; 1159 x->len = 2; 1160 spi_message_add_tail(x, m); 1161 } 1162 } 1163 1164 /* power down */ 1165 ts->msg_count++; 1166 m++; 1167 spi_message_init(m); 1168 m->context = ts; 1169 1170 if (ts->model == 7845) { 1171 x++; 1172 packet->pwrdown_cmd[0] = PWRDOWN; 1173 packet->pwrdown_cmd[1] = 0; 1174 packet->pwrdown_cmd[2] = 0; 1175 x->tx_buf = &packet->pwrdown_cmd[0]; 1176 x->len = 3; 1177 } else { 1178 x++; 1179 packet->pwrdown = PWRDOWN; 1180 x->tx_buf = &packet->pwrdown; 1181 x->len = 1; 1182 spi_message_add_tail(x, m); 1183 1184 x++; 1185 x->rx_buf = &packet->dummy; 1186 x->len = 2; 1187 } 1188 1189 CS_CHANGE(*x); 1190 spi_message_add_tail(x, m); 1191 } 1192 1193 static int __devinit ads7846_probe(struct spi_device *spi) 1194 { 1195 struct ads7846 *ts; 1196 struct ads7846_packet *packet; 1197 struct input_dev *input_dev; 1198 struct ads7846_platform_data *pdata = spi->dev.platform_data; 1199 unsigned long irq_flags; 1200 int err; 1201 1202 if (!spi->irq) { 1203 dev_dbg(&spi->dev, "no IRQ?\n"); 1204 return -ENODEV; 1205 } 1206 1207 if (!pdata) { 1208 dev_dbg(&spi->dev, "no platform data?\n"); 1209 return -ENODEV; 1210 } 1211 1212 /* don't exceed max specified sample rate */ 1213 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { 1214 dev_dbg(&spi->dev, "f(sample) %d KHz?\n", 1215 (spi->max_speed_hz/SAMPLE_BITS)/1000); 1216 return -EINVAL; 1217 } 1218 1219 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except 1220 * that even if the hardware can do that, the SPI controller driver 1221 * may not. So we stick to very-portable 8 bit words, both RX and TX. 1222 */ 1223 spi->bits_per_word = 8; 1224 spi->mode = SPI_MODE_0; 1225 err = spi_setup(spi); 1226 if (err < 0) 1227 return err; 1228 1229 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); 1230 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL); 1231 input_dev = input_allocate_device(); 1232 if (!ts || !packet || !input_dev) { 1233 err = -ENOMEM; 1234 goto err_free_mem; 1235 } 1236 1237 dev_set_drvdata(&spi->dev, ts); 1238 1239 ts->packet = packet; 1240 ts->spi = spi; 1241 ts->input = input_dev; 1242 ts->vref_mv = pdata->vref_mv; 1243 ts->swap_xy = pdata->swap_xy; 1244 1245 mutex_init(&ts->lock); 1246 init_waitqueue_head(&ts->wait); 1247 1248 ts->model = pdata->model ? : 7846; 1249 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; 1250 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; 1251 ts->pressure_max = pdata->pressure_max ? : ~0; 1252 1253 if (pdata->filter != NULL) { 1254 if (pdata->filter_init != NULL) { 1255 err = pdata->filter_init(pdata, &ts->filter_data); 1256 if (err < 0) 1257 goto err_free_mem; 1258 } 1259 ts->filter = pdata->filter; 1260 ts->filter_cleanup = pdata->filter_cleanup; 1261 } else if (pdata->debounce_max) { 1262 ts->debounce_max = pdata->debounce_max; 1263 if (ts->debounce_max < 2) 1264 ts->debounce_max = 2; 1265 ts->debounce_tol = pdata->debounce_tol; 1266 ts->debounce_rep = pdata->debounce_rep; 1267 ts->filter = ads7846_debounce_filter; 1268 ts->filter_data = ts; 1269 } else { 1270 ts->filter = ads7846_no_filter; 1271 } 1272 1273 err = ads7846_setup_pendown(spi, ts); 1274 if (err) 1275 goto err_cleanup_filter; 1276 1277 if (pdata->penirq_recheck_delay_usecs) 1278 ts->penirq_recheck_delay_usecs = 1279 pdata->penirq_recheck_delay_usecs; 1280 1281 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync; 1282 1283 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev)); 1284 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model); 1285 1286 input_dev->name = ts->name; 1287 input_dev->phys = ts->phys; 1288 input_dev->dev.parent = &spi->dev; 1289 1290 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 1291 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 1292 input_set_abs_params(input_dev, ABS_X, 1293 pdata->x_min ? : 0, 1294 pdata->x_max ? : MAX_12BIT, 1295 0, 0); 1296 input_set_abs_params(input_dev, ABS_Y, 1297 pdata->y_min ? : 0, 1298 pdata->y_max ? : MAX_12BIT, 1299 0, 0); 1300 input_set_abs_params(input_dev, ABS_PRESSURE, 1301 pdata->pressure_min, pdata->pressure_max, 0, 0); 1302 1303 ads7846_setup_spi_msg(ts, pdata); 1304 1305 ts->reg = regulator_get(&spi->dev, "vcc"); 1306 if (IS_ERR(ts->reg)) { 1307 err = PTR_ERR(ts->reg); 1308 dev_err(&spi->dev, "unable to get regulator: %d\n", err); 1309 goto err_free_gpio; 1310 } 1311 1312 err = regulator_enable(ts->reg); 1313 if (err) { 1314 dev_err(&spi->dev, "unable to enable regulator: %d\n", err); 1315 goto err_put_regulator; 1316 } 1317 1318 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING; 1319 irq_flags |= IRQF_ONESHOT; 1320 1321 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq, 1322 irq_flags, spi->dev.driver->name, ts); 1323 if (err && !pdata->irq_flags) { 1324 dev_info(&spi->dev, 1325 "trying pin change workaround on irq %d\n", spi->irq); 1326 irq_flags |= IRQF_TRIGGER_RISING; 1327 err = request_threaded_irq(spi->irq, 1328 ads7846_hard_irq, ads7846_irq, 1329 irq_flags, spi->dev.driver->name, ts); 1330 } 1331 1332 if (err) { 1333 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); 1334 goto err_disable_regulator; 1335 } 1336 1337 err = ads784x_hwmon_register(spi, ts); 1338 if (err) 1339 goto err_free_irq; 1340 1341 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); 1342 1343 /* 1344 * Take a first sample, leaving nPENIRQ active and vREF off; avoid 1345 * the touchscreen, in case it's not connected. 1346 */ 1347 if (ts->model == 7845) 1348 ads7845_read12_ser(&spi->dev, PWRDOWN); 1349 else 1350 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux)); 1351 1352 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); 1353 if (err) 1354 goto err_remove_hwmon; 1355 1356 err = input_register_device(input_dev); 1357 if (err) 1358 goto err_remove_attr_group; 1359 1360 device_init_wakeup(&spi->dev, pdata->wakeup); 1361 1362 return 0; 1363 1364 err_remove_attr_group: 1365 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1366 err_remove_hwmon: 1367 ads784x_hwmon_unregister(spi, ts); 1368 err_free_irq: 1369 free_irq(spi->irq, ts); 1370 err_disable_regulator: 1371 regulator_disable(ts->reg); 1372 err_put_regulator: 1373 regulator_put(ts->reg); 1374 err_free_gpio: 1375 if (!ts->get_pendown_state) 1376 gpio_free(ts->gpio_pendown); 1377 err_cleanup_filter: 1378 if (ts->filter_cleanup) 1379 ts->filter_cleanup(ts->filter_data); 1380 err_free_mem: 1381 input_free_device(input_dev); 1382 kfree(packet); 1383 kfree(ts); 1384 return err; 1385 } 1386 1387 static int __devexit ads7846_remove(struct spi_device *spi) 1388 { 1389 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 1390 1391 device_init_wakeup(&spi->dev, false); 1392 1393 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1394 1395 ads7846_disable(ts); 1396 free_irq(ts->spi->irq, ts); 1397 1398 input_unregister_device(ts->input); 1399 1400 ads784x_hwmon_unregister(spi, ts); 1401 1402 regulator_disable(ts->reg); 1403 regulator_put(ts->reg); 1404 1405 if (!ts->get_pendown_state) { 1406 /* 1407 * If we are not using specialized pendown method we must 1408 * have been relying on gpio we set up ourselves. 1409 */ 1410 gpio_free(ts->gpio_pendown); 1411 } 1412 1413 if (ts->filter_cleanup) 1414 ts->filter_cleanup(ts->filter_data); 1415 1416 kfree(ts->packet); 1417 kfree(ts); 1418 1419 dev_dbg(&spi->dev, "unregistered touchscreen\n"); 1420 1421 return 0; 1422 } 1423 1424 static struct spi_driver ads7846_driver = { 1425 .driver = { 1426 .name = "ads7846", 1427 .bus = &spi_bus_type, 1428 .owner = THIS_MODULE, 1429 .pm = &ads7846_pm, 1430 }, 1431 .probe = ads7846_probe, 1432 .remove = __devexit_p(ads7846_remove), 1433 }; 1434 1435 static int __init ads7846_init(void) 1436 { 1437 return spi_register_driver(&ads7846_driver); 1438 } 1439 module_init(ads7846_init); 1440 1441 static void __exit ads7846_exit(void) 1442 { 1443 spi_unregister_driver(&ads7846_driver); 1444 } 1445 module_exit(ads7846_exit); 1446 1447 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); 1448 MODULE_LICENSE("GPL"); 1449 MODULE_ALIAS("spi:ads7846"); 1450