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/hwmon.h> 21 #include <linux/init.h> 22 #include <linux/err.h> 23 #include <linux/delay.h> 24 #include <linux/input.h> 25 #include <linux/interrupt.h> 26 #include <linux/slab.h> 27 #include <linux/spi/spi.h> 28 #include <linux/spi/ads7846.h> 29 #include <asm/irq.h> 30 31 32 /* 33 * This code has been heavily tested on a Nokia 770, and lightly 34 * tested on other ads7846 devices (OSK/Mistral, Lubbock). 35 * TSC2046 is just newer ads7846 silicon. 36 * Support for ads7843 tested on Atmel at91sam926x-EK. 37 * Support for ads7845 has only been stubbed in. 38 * 39 * IRQ handling needs a workaround because of a shortcoming in handling 40 * edge triggered IRQs on some platforms like the OMAP1/2. These 41 * platforms don't handle the ARM lazy IRQ disabling properly, thus we 42 * have to maintain our own SW IRQ disabled status. This should be 43 * removed as soon as the affected platform's IRQ handling is fixed. 44 * 45 * app note sbaa036 talks in more detail about accurate sampling... 46 * that ought to help in situations like LCDs inducing noise (which 47 * can also be helped by using synch signals) and more generally. 48 * This driver tries to utilize the measures described in the app 49 * note. The strength of filtering can be set in the board-* specific 50 * files. 51 */ 52 53 #define TS_POLL_DELAY (1 * 1000000) /* ns delay before the first sample */ 54 #define TS_POLL_PERIOD (5 * 1000000) /* ns delay between samples */ 55 56 /* this driver doesn't aim at the peak continuous sample rate */ 57 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */) 58 59 struct ts_event { 60 /* For portability, we can't read 12 bit values using SPI (which 61 * would make the controller deliver them as native byteorder u16 62 * with msbs zeroed). Instead, we read them as two 8-bit values, 63 * *** WHICH NEED BYTESWAPPING *** and range adjustment. 64 */ 65 u16 x; 66 u16 y; 67 u16 z1, z2; 68 int ignore; 69 }; 70 71 struct ads7846 { 72 struct input_dev *input; 73 char phys[32]; 74 75 struct spi_device *spi; 76 77 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 78 struct attribute_group *attr_group; 79 struct device *hwmon; 80 #endif 81 82 u16 model; 83 u16 vref_mv; 84 u16 vref_delay_usecs; 85 u16 x_plate_ohms; 86 u16 pressure_max; 87 88 u8 read_x, read_y, read_z1, read_z2, pwrdown; 89 u16 dummy; /* for the pwrdown read */ 90 struct ts_event tc; 91 92 struct spi_transfer xfer[18]; 93 struct spi_message msg[5]; 94 struct spi_message *last_msg; 95 int msg_idx; 96 int read_cnt; 97 int read_rep; 98 int last_read; 99 100 u16 debounce_max; 101 u16 debounce_tol; 102 u16 debounce_rep; 103 104 u16 penirq_recheck_delay_usecs; 105 106 spinlock_t lock; 107 struct hrtimer timer; 108 unsigned pendown:1; /* P: lock */ 109 unsigned pending:1; /* P: lock */ 110 // FIXME remove "irq_disabled" 111 unsigned irq_disabled:1; /* P: lock */ 112 unsigned disabled:1; 113 unsigned is_suspended:1; 114 115 int (*filter)(void *data, int data_idx, int *val); 116 void *filter_data; 117 void (*filter_cleanup)(void *data); 118 int (*get_pendown_state)(void); 119 }; 120 121 /* leave chip selected when we're done, for quicker re-select? */ 122 #if 0 123 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) 124 #else 125 #define CS_CHANGE(xfer) ((xfer).cs_change = 0) 126 #endif 127 128 /*--------------------------------------------------------------------------*/ 129 130 /* The ADS7846 has touchscreen and other sensors. 131 * Earlier ads784x chips are somewhat compatible. 132 */ 133 #define ADS_START (1 << 7) 134 #define ADS_A2A1A0_d_y (1 << 4) /* differential */ 135 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ 136 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ 137 #define ADS_A2A1A0_d_x (5 << 4) /* differential */ 138 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ 139 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ 140 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ 141 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ 142 #define ADS_8_BIT (1 << 3) 143 #define ADS_12_BIT (0 << 3) 144 #define ADS_SER (1 << 2) /* non-differential */ 145 #define ADS_DFR (0 << 2) /* differential */ 146 #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ 147 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ 148 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ 149 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ 150 151 #define MAX_12BIT ((1<<12)-1) 152 153 /* leave ADC powered up (disables penirq) between differential samples */ 154 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ 155 | ADS_12_BIT | ADS_DFR | \ 156 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) 157 158 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) 159 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) 160 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) 161 162 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) 163 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ 164 165 /* single-ended samples need to first power up reference voltage; 166 * we leave both ADC and VREF powered 167 */ 168 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ 169 | ADS_12_BIT | ADS_SER) 170 171 #define REF_ON (READ_12BIT_DFR(x, 1, 1)) 172 #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) 173 174 /*--------------------------------------------------------------------------*/ 175 176 /* 177 * Non-touchscreen sensors only use single-ended conversions. 178 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; 179 * ads7846 lets that pin be unconnected, to use internal vREF. 180 */ 181 182 struct ser_req { 183 u8 ref_on; 184 u8 command; 185 u8 ref_off; 186 u16 scratch; 187 __be16 sample; 188 struct spi_message msg; 189 struct spi_transfer xfer[6]; 190 }; 191 192 static void ads7846_enable(struct ads7846 *ts); 193 static void ads7846_disable(struct ads7846 *ts); 194 195 static int device_suspended(struct device *dev) 196 { 197 struct ads7846 *ts = dev_get_drvdata(dev); 198 return ts->is_suspended || ts->disabled; 199 } 200 201 static int ads7846_read12_ser(struct device *dev, unsigned command) 202 { 203 struct spi_device *spi = to_spi_device(dev); 204 struct ads7846 *ts = dev_get_drvdata(dev); 205 struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); 206 int status; 207 int use_internal; 208 209 if (!req) 210 return -ENOMEM; 211 212 spi_message_init(&req->msg); 213 214 /* FIXME boards with ads7846 might use external vref instead ... */ 215 use_internal = (ts->model == 7846); 216 217 /* maybe turn on internal vREF, and let it settle */ 218 if (use_internal) { 219 req->ref_on = REF_ON; 220 req->xfer[0].tx_buf = &req->ref_on; 221 req->xfer[0].len = 1; 222 spi_message_add_tail(&req->xfer[0], &req->msg); 223 224 req->xfer[1].rx_buf = &req->scratch; 225 req->xfer[1].len = 2; 226 227 /* for 1uF, settle for 800 usec; no cap, 100 usec. */ 228 req->xfer[1].delay_usecs = ts->vref_delay_usecs; 229 spi_message_add_tail(&req->xfer[1], &req->msg); 230 } 231 232 /* take sample */ 233 req->command = (u8) command; 234 req->xfer[2].tx_buf = &req->command; 235 req->xfer[2].len = 1; 236 spi_message_add_tail(&req->xfer[2], &req->msg); 237 238 req->xfer[3].rx_buf = &req->sample; 239 req->xfer[3].len = 2; 240 spi_message_add_tail(&req->xfer[3], &req->msg); 241 242 /* REVISIT: take a few more samples, and compare ... */ 243 244 /* converter in low power mode & enable PENIRQ */ 245 req->ref_off = PWRDOWN; 246 req->xfer[4].tx_buf = &req->ref_off; 247 req->xfer[4].len = 1; 248 spi_message_add_tail(&req->xfer[4], &req->msg); 249 250 req->xfer[5].rx_buf = &req->scratch; 251 req->xfer[5].len = 2; 252 CS_CHANGE(req->xfer[5]); 253 spi_message_add_tail(&req->xfer[5], &req->msg); 254 255 ts->irq_disabled = 1; 256 disable_irq(spi->irq); 257 status = spi_sync(spi, &req->msg); 258 ts->irq_disabled = 0; 259 enable_irq(spi->irq); 260 261 if (status == 0) { 262 /* on-wire is a must-ignore bit, a BE12 value, then padding */ 263 status = be16_to_cpu(req->sample); 264 status = status >> 3; 265 status &= 0x0fff; 266 } 267 268 kfree(req); 269 return status; 270 } 271 272 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 273 274 #define SHOW(name, var, adjust) static ssize_t \ 275 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 276 { \ 277 struct ads7846 *ts = dev_get_drvdata(dev); \ 278 ssize_t v = ads7846_read12_ser(dev, \ 279 READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \ 280 if (v < 0) \ 281 return v; \ 282 return sprintf(buf, "%u\n", adjust(ts, v)); \ 283 } \ 284 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); 285 286 287 /* Sysfs conventions report temperatures in millidegrees Celcius. 288 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high 289 * accuracy scheme without calibration data. For now we won't try either; 290 * userspace sees raw sensor values, and must scale/calibrate appropriately. 291 */ 292 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) 293 { 294 return v; 295 } 296 297 SHOW(temp0, temp0, null_adjust) /* temp1_input */ 298 SHOW(temp1, temp1, null_adjust) /* temp2_input */ 299 300 301 /* sysfs conventions report voltages in millivolts. We can convert voltages 302 * if we know vREF. userspace may need to scale vAUX to match the board's 303 * external resistors; we assume that vBATT only uses the internal ones. 304 */ 305 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 306 { 307 unsigned retval = v; 308 309 /* external resistors may scale vAUX into 0..vREF */ 310 retval *= ts->vref_mv; 311 retval = retval >> 12; 312 return retval; 313 } 314 315 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) 316 { 317 unsigned retval = vaux_adjust(ts, v); 318 319 /* ads7846 has a resistor ladder to scale this signal down */ 320 if (ts->model == 7846) 321 retval *= 4; 322 return retval; 323 } 324 325 SHOW(in0_input, vaux, vaux_adjust) 326 SHOW(in1_input, vbatt, vbatt_adjust) 327 328 329 static struct attribute *ads7846_attributes[] = { 330 &dev_attr_temp0.attr, 331 &dev_attr_temp1.attr, 332 &dev_attr_in0_input.attr, 333 &dev_attr_in1_input.attr, 334 NULL, 335 }; 336 337 static struct attribute_group ads7846_attr_group = { 338 .attrs = ads7846_attributes, 339 }; 340 341 static struct attribute *ads7843_attributes[] = { 342 &dev_attr_in0_input.attr, 343 &dev_attr_in1_input.attr, 344 NULL, 345 }; 346 347 static struct attribute_group ads7843_attr_group = { 348 .attrs = ads7843_attributes, 349 }; 350 351 static struct attribute *ads7845_attributes[] = { 352 &dev_attr_in0_input.attr, 353 NULL, 354 }; 355 356 static struct attribute_group ads7845_attr_group = { 357 .attrs = ads7845_attributes, 358 }; 359 360 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 361 { 362 struct device *hwmon; 363 int err; 364 365 /* hwmon sensors need a reference voltage */ 366 switch (ts->model) { 367 case 7846: 368 if (!ts->vref_mv) { 369 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); 370 ts->vref_mv = 2500; 371 } 372 break; 373 case 7845: 374 case 7843: 375 if (!ts->vref_mv) { 376 dev_warn(&spi->dev, 377 "external vREF for ADS%d not specified\n", 378 ts->model); 379 return 0; 380 } 381 break; 382 } 383 384 /* different chips have different sensor groups */ 385 switch (ts->model) { 386 case 7846: 387 ts->attr_group = &ads7846_attr_group; 388 break; 389 case 7845: 390 ts->attr_group = &ads7845_attr_group; 391 break; 392 case 7843: 393 ts->attr_group = &ads7843_attr_group; 394 break; 395 default: 396 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); 397 return 0; 398 } 399 400 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); 401 if (err) 402 return err; 403 404 hwmon = hwmon_device_register(&spi->dev); 405 if (IS_ERR(hwmon)) { 406 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 407 return PTR_ERR(hwmon); 408 } 409 410 ts->hwmon = hwmon; 411 return 0; 412 } 413 414 static void ads784x_hwmon_unregister(struct spi_device *spi, 415 struct ads7846 *ts) 416 { 417 if (ts->hwmon) { 418 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 419 hwmon_device_unregister(ts->hwmon); 420 } 421 } 422 423 #else 424 static inline int ads784x_hwmon_register(struct spi_device *spi, 425 struct ads7846 *ts) 426 { 427 return 0; 428 } 429 430 static inline void ads784x_hwmon_unregister(struct spi_device *spi, 431 struct ads7846 *ts) 432 { 433 } 434 #endif 435 436 static int is_pen_down(struct device *dev) 437 { 438 struct ads7846 *ts = dev_get_drvdata(dev); 439 440 return ts->pendown; 441 } 442 443 static ssize_t ads7846_pen_down_show(struct device *dev, 444 struct device_attribute *attr, char *buf) 445 { 446 return sprintf(buf, "%u\n", is_pen_down(dev)); 447 } 448 449 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); 450 451 static ssize_t ads7846_disable_show(struct device *dev, 452 struct device_attribute *attr, char *buf) 453 { 454 struct ads7846 *ts = dev_get_drvdata(dev); 455 456 return sprintf(buf, "%u\n", ts->disabled); 457 } 458 459 static ssize_t ads7846_disable_store(struct device *dev, 460 struct device_attribute *attr, 461 const char *buf, size_t count) 462 { 463 struct ads7846 *ts = dev_get_drvdata(dev); 464 char *endp; 465 int i; 466 467 i = simple_strtoul(buf, &endp, 10); 468 spin_lock_irq(&ts->lock); 469 470 if (i) 471 ads7846_disable(ts); 472 else 473 ads7846_enable(ts); 474 475 spin_unlock_irq(&ts->lock); 476 477 return count; 478 } 479 480 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); 481 482 static struct attribute *ads784x_attributes[] = { 483 &dev_attr_pen_down.attr, 484 &dev_attr_disable.attr, 485 NULL, 486 }; 487 488 static struct attribute_group ads784x_attr_group = { 489 .attrs = ads784x_attributes, 490 }; 491 492 /*--------------------------------------------------------------------------*/ 493 494 /* 495 * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, 496 * to retrieve touchscreen status. 497 * 498 * The SPI transfer completion callback does the real work. It reports 499 * touchscreen events and reactivates the timer (or IRQ) as appropriate. 500 */ 501 502 static void ads7846_rx(void *ads) 503 { 504 struct ads7846 *ts = ads; 505 unsigned Rt; 506 u16 x, y, z1, z2; 507 508 /* ads7846_rx_val() did in-place conversion (including byteswap) from 509 * on-the-wire format as part of debouncing to get stable readings. 510 */ 511 x = ts->tc.x; 512 y = ts->tc.y; 513 z1 = ts->tc.z1; 514 z2 = ts->tc.z2; 515 516 /* range filtering */ 517 if (x == MAX_12BIT) 518 x = 0; 519 520 if (ts->model == 7843) { 521 Rt = ts->pressure_max / 2; 522 } else if (likely(x && z1)) { 523 /* compute touch pressure resistance using equation #2 */ 524 Rt = z2; 525 Rt -= z1; 526 Rt *= x; 527 Rt *= ts->x_plate_ohms; 528 Rt /= z1; 529 Rt = (Rt + 2047) >> 12; 530 } else { 531 Rt = 0; 532 } 533 534 /* Sample found inconsistent by debouncing or pressure is beyond 535 * the maximum. Don't report it to user space, repeat at least 536 * once more the measurement 537 */ 538 if (ts->tc.ignore || Rt > ts->pressure_max) { 539 #ifdef VERBOSE 540 pr_debug("%s: ignored %d pressure %d\n", 541 ts->spi->dev.bus_id, ts->tc.ignore, Rt); 542 #endif 543 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 544 HRTIMER_MODE_REL); 545 return; 546 } 547 548 /* Maybe check the pendown state before reporting. This discards 549 * false readings when the pen is lifted. 550 */ 551 if (ts->penirq_recheck_delay_usecs) { 552 udelay(ts->penirq_recheck_delay_usecs); 553 if (!ts->get_pendown_state()) 554 Rt = 0; 555 } 556 557 /* NOTE: We can't rely on the pressure to determine the pen down 558 * state, even this controller has a pressure sensor. The pressure 559 * value can fluctuate for quite a while after lifting the pen and 560 * in some cases may not even settle at the expected value. 561 * 562 * The only safe way to check for the pen up condition is in the 563 * timer by reading the pen signal state (it's a GPIO _and_ IRQ). 564 */ 565 if (Rt) { 566 struct input_dev *input = ts->input; 567 568 if (!ts->pendown) { 569 input_report_key(input, BTN_TOUCH, 1); 570 ts->pendown = 1; 571 #ifdef VERBOSE 572 dev_dbg(&ts->spi->dev, "DOWN\n"); 573 #endif 574 } 575 input_report_abs(input, ABS_X, x); 576 input_report_abs(input, ABS_Y, y); 577 input_report_abs(input, ABS_PRESSURE, Rt); 578 579 input_sync(input); 580 #ifdef VERBOSE 581 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); 582 #endif 583 } 584 585 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 586 HRTIMER_MODE_REL); 587 } 588 589 static int ads7846_debounce(void *ads, int data_idx, int *val) 590 { 591 struct ads7846 *ts = ads; 592 593 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { 594 /* Start over collecting consistent readings. */ 595 ts->read_rep = 0; 596 /* Repeat it, if this was the first read or the read 597 * wasn't consistent enough. */ 598 if (ts->read_cnt < ts->debounce_max) { 599 ts->last_read = *val; 600 ts->read_cnt++; 601 return ADS7846_FILTER_REPEAT; 602 } else { 603 /* Maximum number of debouncing reached and still 604 * not enough number of consistent readings. Abort 605 * the whole sample, repeat it in the next sampling 606 * period. 607 */ 608 ts->read_cnt = 0; 609 return ADS7846_FILTER_IGNORE; 610 } 611 } else { 612 if (++ts->read_rep > ts->debounce_rep) { 613 /* Got a good reading for this coordinate, 614 * go for the next one. */ 615 ts->read_cnt = 0; 616 ts->read_rep = 0; 617 return ADS7846_FILTER_OK; 618 } else { 619 /* Read more values that are consistent. */ 620 ts->read_cnt++; 621 return ADS7846_FILTER_REPEAT; 622 } 623 } 624 } 625 626 static int ads7846_no_filter(void *ads, int data_idx, int *val) 627 { 628 return ADS7846_FILTER_OK; 629 } 630 631 static void ads7846_rx_val(void *ads) 632 { 633 struct ads7846 *ts = ads; 634 struct spi_message *m; 635 struct spi_transfer *t; 636 int val; 637 int action; 638 int status; 639 640 m = &ts->msg[ts->msg_idx]; 641 t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 642 643 /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; 644 * built from two 8 bit values written msb-first. 645 */ 646 val = be16_to_cpup((__be16 *)t->rx_buf) >> 3; 647 648 action = ts->filter(ts->filter_data, ts->msg_idx, &val); 649 switch (action) { 650 case ADS7846_FILTER_REPEAT: 651 break; 652 case ADS7846_FILTER_IGNORE: 653 ts->tc.ignore = 1; 654 /* Last message will contain ads7846_rx() as the 655 * completion function. 656 */ 657 m = ts->last_msg; 658 break; 659 case ADS7846_FILTER_OK: 660 *(u16 *)t->rx_buf = val; 661 ts->tc.ignore = 0; 662 m = &ts->msg[++ts->msg_idx]; 663 break; 664 default: 665 BUG(); 666 } 667 status = spi_async(ts->spi, m); 668 if (status) 669 dev_err(&ts->spi->dev, "spi_async --> %d\n", 670 status); 671 } 672 673 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle) 674 { 675 struct ads7846 *ts = container_of(handle, struct ads7846, timer); 676 int status = 0; 677 678 spin_lock_irq(&ts->lock); 679 680 if (unlikely(!ts->get_pendown_state() || 681 device_suspended(&ts->spi->dev))) { 682 if (ts->pendown) { 683 struct input_dev *input = ts->input; 684 685 input_report_key(input, BTN_TOUCH, 0); 686 input_report_abs(input, ABS_PRESSURE, 0); 687 input_sync(input); 688 689 ts->pendown = 0; 690 #ifdef VERBOSE 691 dev_dbg(&ts->spi->dev, "UP\n"); 692 #endif 693 } 694 695 /* measurement cycle ended */ 696 if (!device_suspended(&ts->spi->dev)) { 697 ts->irq_disabled = 0; 698 enable_irq(ts->spi->irq); 699 } 700 ts->pending = 0; 701 } else { 702 /* pen is still down, continue with the measurement */ 703 ts->msg_idx = 0; 704 status = spi_async(ts->spi, &ts->msg[0]); 705 if (status) 706 dev_err(&ts->spi->dev, "spi_async --> %d\n", status); 707 } 708 709 spin_unlock_irq(&ts->lock); 710 return HRTIMER_NORESTART; 711 } 712 713 static irqreturn_t ads7846_irq(int irq, void *handle) 714 { 715 struct ads7846 *ts = handle; 716 unsigned long flags; 717 718 spin_lock_irqsave(&ts->lock, flags); 719 if (likely(ts->get_pendown_state())) { 720 if (!ts->irq_disabled) { 721 /* The ARM do_simple_IRQ() dispatcher doesn't act 722 * like the other dispatchers: it will report IRQs 723 * even after they've been disabled. We work around 724 * that here. (The "generic irq" framework may help...) 725 */ 726 ts->irq_disabled = 1; 727 disable_irq(ts->spi->irq); 728 ts->pending = 1; 729 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY), 730 HRTIMER_MODE_REL); 731 } 732 } 733 spin_unlock_irqrestore(&ts->lock, flags); 734 735 return IRQ_HANDLED; 736 } 737 738 /*--------------------------------------------------------------------------*/ 739 740 /* Must be called with ts->lock held */ 741 static void ads7846_disable(struct ads7846 *ts) 742 { 743 if (ts->disabled) 744 return; 745 746 ts->disabled = 1; 747 748 /* are we waiting for IRQ, or polling? */ 749 if (!ts->pending) { 750 ts->irq_disabled = 1; 751 disable_irq(ts->spi->irq); 752 } else { 753 /* the timer will run at least once more, and 754 * leave everything in a clean state, IRQ disabled 755 */ 756 while (ts->pending) { 757 spin_unlock_irq(&ts->lock); 758 msleep(1); 759 spin_lock_irq(&ts->lock); 760 } 761 } 762 763 /* we know the chip's in lowpower mode since we always 764 * leave it that way after every request 765 */ 766 767 } 768 769 /* Must be called with ts->lock held */ 770 static void ads7846_enable(struct ads7846 *ts) 771 { 772 if (!ts->disabled) 773 return; 774 775 ts->disabled = 0; 776 ts->irq_disabled = 0; 777 enable_irq(ts->spi->irq); 778 } 779 780 static int ads7846_suspend(struct spi_device *spi, pm_message_t message) 781 { 782 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 783 784 spin_lock_irq(&ts->lock); 785 786 ts->is_suspended = 1; 787 ads7846_disable(ts); 788 789 spin_unlock_irq(&ts->lock); 790 791 return 0; 792 793 } 794 795 static int ads7846_resume(struct spi_device *spi) 796 { 797 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 798 799 spin_lock_irq(&ts->lock); 800 801 ts->is_suspended = 0; 802 ads7846_enable(ts); 803 804 spin_unlock_irq(&ts->lock); 805 806 return 0; 807 } 808 809 static int __devinit ads7846_probe(struct spi_device *spi) 810 { 811 struct ads7846 *ts; 812 struct input_dev *input_dev; 813 struct ads7846_platform_data *pdata = spi->dev.platform_data; 814 struct spi_message *m; 815 struct spi_transfer *x; 816 int vref; 817 int err; 818 819 if (!spi->irq) { 820 dev_dbg(&spi->dev, "no IRQ?\n"); 821 return -ENODEV; 822 } 823 824 if (!pdata) { 825 dev_dbg(&spi->dev, "no platform data?\n"); 826 return -ENODEV; 827 } 828 829 /* don't exceed max specified sample rate */ 830 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { 831 dev_dbg(&spi->dev, "f(sample) %d KHz?\n", 832 (spi->max_speed_hz/SAMPLE_BITS)/1000); 833 return -EINVAL; 834 } 835 836 /* REVISIT when the irq can be triggered active-low, or if for some 837 * reason the touchscreen isn't hooked up, we don't need to access 838 * the pendown state. 839 */ 840 if (pdata->get_pendown_state == NULL) { 841 dev_dbg(&spi->dev, "no get_pendown_state function?\n"); 842 return -EINVAL; 843 } 844 845 /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except 846 * that even if the hardware can do that, the SPI controller driver 847 * may not. So we stick to very-portable 8 bit words, both RX and TX. 848 */ 849 spi->bits_per_word = 8; 850 spi->mode = SPI_MODE_0; 851 err = spi_setup(spi); 852 if (err < 0) 853 return err; 854 855 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); 856 input_dev = input_allocate_device(); 857 if (!ts || !input_dev) { 858 err = -ENOMEM; 859 goto err_free_mem; 860 } 861 862 dev_set_drvdata(&spi->dev, ts); 863 864 ts->spi = spi; 865 ts->input = input_dev; 866 ts->vref_mv = pdata->vref_mv; 867 868 hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 869 ts->timer.function = ads7846_timer; 870 871 spin_lock_init(&ts->lock); 872 873 ts->model = pdata->model ? : 7846; 874 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; 875 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; 876 ts->pressure_max = pdata->pressure_max ? : ~0; 877 878 if (pdata->filter != NULL) { 879 if (pdata->filter_init != NULL) { 880 err = pdata->filter_init(pdata, &ts->filter_data); 881 if (err < 0) 882 goto err_free_mem; 883 } 884 ts->filter = pdata->filter; 885 ts->filter_cleanup = pdata->filter_cleanup; 886 } else if (pdata->debounce_max) { 887 ts->debounce_max = pdata->debounce_max; 888 if (ts->debounce_max < 2) 889 ts->debounce_max = 2; 890 ts->debounce_tol = pdata->debounce_tol; 891 ts->debounce_rep = pdata->debounce_rep; 892 ts->filter = ads7846_debounce; 893 ts->filter_data = ts; 894 } else 895 ts->filter = ads7846_no_filter; 896 ts->get_pendown_state = pdata->get_pendown_state; 897 898 if (pdata->penirq_recheck_delay_usecs) 899 ts->penirq_recheck_delay_usecs = 900 pdata->penirq_recheck_delay_usecs; 901 902 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); 903 904 input_dev->name = "ADS784x Touchscreen"; 905 input_dev->phys = ts->phys; 906 input_dev->dev.parent = &spi->dev; 907 908 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 909 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 910 input_set_abs_params(input_dev, ABS_X, 911 pdata->x_min ? : 0, 912 pdata->x_max ? : MAX_12BIT, 913 0, 0); 914 input_set_abs_params(input_dev, ABS_Y, 915 pdata->y_min ? : 0, 916 pdata->y_max ? : MAX_12BIT, 917 0, 0); 918 input_set_abs_params(input_dev, ABS_PRESSURE, 919 pdata->pressure_min, pdata->pressure_max, 0, 0); 920 921 vref = pdata->keep_vref_on; 922 923 /* set up the transfers to read touchscreen state; this assumes we 924 * use formula #2 for pressure, not #3. 925 */ 926 m = &ts->msg[0]; 927 x = ts->xfer; 928 929 spi_message_init(m); 930 931 /* y- still on; turn on only y+ (and ADC) */ 932 ts->read_y = READ_Y(vref); 933 x->tx_buf = &ts->read_y; 934 x->len = 1; 935 spi_message_add_tail(x, m); 936 937 x++; 938 x->rx_buf = &ts->tc.y; 939 x->len = 2; 940 spi_message_add_tail(x, m); 941 942 /* the first sample after switching drivers can be low quality; 943 * optionally discard it, using a second one after the signals 944 * have had enough time to stabilize. 945 */ 946 if (pdata->settle_delay_usecs) { 947 x->delay_usecs = pdata->settle_delay_usecs; 948 949 x++; 950 x->tx_buf = &ts->read_y; 951 x->len = 1; 952 spi_message_add_tail(x, m); 953 954 x++; 955 x->rx_buf = &ts->tc.y; 956 x->len = 2; 957 spi_message_add_tail(x, m); 958 } 959 960 m->complete = ads7846_rx_val; 961 m->context = ts; 962 963 m++; 964 spi_message_init(m); 965 966 /* turn y- off, x+ on, then leave in lowpower */ 967 x++; 968 ts->read_x = READ_X(vref); 969 x->tx_buf = &ts->read_x; 970 x->len = 1; 971 spi_message_add_tail(x, m); 972 973 x++; 974 x->rx_buf = &ts->tc.x; 975 x->len = 2; 976 spi_message_add_tail(x, m); 977 978 /* ... maybe discard first sample ... */ 979 if (pdata->settle_delay_usecs) { 980 x->delay_usecs = pdata->settle_delay_usecs; 981 982 x++; 983 x->tx_buf = &ts->read_x; 984 x->len = 1; 985 spi_message_add_tail(x, m); 986 987 x++; 988 x->rx_buf = &ts->tc.x; 989 x->len = 2; 990 spi_message_add_tail(x, m); 991 } 992 993 m->complete = ads7846_rx_val; 994 m->context = ts; 995 996 /* turn y+ off, x- on; we'll use formula #2 */ 997 if (ts->model == 7846) { 998 m++; 999 spi_message_init(m); 1000 1001 x++; 1002 ts->read_z1 = READ_Z1(vref); 1003 x->tx_buf = &ts->read_z1; 1004 x->len = 1; 1005 spi_message_add_tail(x, m); 1006 1007 x++; 1008 x->rx_buf = &ts->tc.z1; 1009 x->len = 2; 1010 spi_message_add_tail(x, m); 1011 1012 /* ... maybe discard first sample ... */ 1013 if (pdata->settle_delay_usecs) { 1014 x->delay_usecs = pdata->settle_delay_usecs; 1015 1016 x++; 1017 x->tx_buf = &ts->read_z1; 1018 x->len = 1; 1019 spi_message_add_tail(x, m); 1020 1021 x++; 1022 x->rx_buf = &ts->tc.z1; 1023 x->len = 2; 1024 spi_message_add_tail(x, m); 1025 } 1026 1027 m->complete = ads7846_rx_val; 1028 m->context = ts; 1029 1030 m++; 1031 spi_message_init(m); 1032 1033 x++; 1034 ts->read_z2 = READ_Z2(vref); 1035 x->tx_buf = &ts->read_z2; 1036 x->len = 1; 1037 spi_message_add_tail(x, m); 1038 1039 x++; 1040 x->rx_buf = &ts->tc.z2; 1041 x->len = 2; 1042 spi_message_add_tail(x, m); 1043 1044 /* ... maybe discard first sample ... */ 1045 if (pdata->settle_delay_usecs) { 1046 x->delay_usecs = pdata->settle_delay_usecs; 1047 1048 x++; 1049 x->tx_buf = &ts->read_z2; 1050 x->len = 1; 1051 spi_message_add_tail(x, m); 1052 1053 x++; 1054 x->rx_buf = &ts->tc.z2; 1055 x->len = 2; 1056 spi_message_add_tail(x, m); 1057 } 1058 1059 m->complete = ads7846_rx_val; 1060 m->context = ts; 1061 } 1062 1063 /* power down */ 1064 m++; 1065 spi_message_init(m); 1066 1067 x++; 1068 ts->pwrdown = PWRDOWN; 1069 x->tx_buf = &ts->pwrdown; 1070 x->len = 1; 1071 spi_message_add_tail(x, m); 1072 1073 x++; 1074 x->rx_buf = &ts->dummy; 1075 x->len = 2; 1076 CS_CHANGE(*x); 1077 spi_message_add_tail(x, m); 1078 1079 m->complete = ads7846_rx; 1080 m->context = ts; 1081 1082 ts->last_msg = m; 1083 1084 if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, 1085 spi->dev.driver->name, ts)) { 1086 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); 1087 err = -EBUSY; 1088 goto err_cleanup_filter; 1089 } 1090 1091 err = ads784x_hwmon_register(spi, ts); 1092 if (err) 1093 goto err_free_irq; 1094 1095 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); 1096 1097 /* take a first sample, leaving nPENIRQ active and vREF off; avoid 1098 * the touchscreen, in case it's not connected. 1099 */ 1100 (void) ads7846_read12_ser(&spi->dev, 1101 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); 1102 1103 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); 1104 if (err) 1105 goto err_remove_hwmon; 1106 1107 err = input_register_device(input_dev); 1108 if (err) 1109 goto err_remove_attr_group; 1110 1111 return 0; 1112 1113 err_remove_attr_group: 1114 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1115 err_remove_hwmon: 1116 ads784x_hwmon_unregister(spi, ts); 1117 err_free_irq: 1118 free_irq(spi->irq, ts); 1119 err_cleanup_filter: 1120 if (ts->filter_cleanup) 1121 ts->filter_cleanup(ts->filter_data); 1122 err_free_mem: 1123 input_free_device(input_dev); 1124 kfree(ts); 1125 return err; 1126 } 1127 1128 static int __devexit ads7846_remove(struct spi_device *spi) 1129 { 1130 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 1131 1132 ads784x_hwmon_unregister(spi, ts); 1133 input_unregister_device(ts->input); 1134 1135 ads7846_suspend(spi, PMSG_SUSPEND); 1136 1137 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1138 1139 free_irq(ts->spi->irq, ts); 1140 /* suspend left the IRQ disabled */ 1141 enable_irq(ts->spi->irq); 1142 1143 if (ts->filter_cleanup) 1144 ts->filter_cleanup(ts->filter_data); 1145 1146 kfree(ts); 1147 1148 dev_dbg(&spi->dev, "unregistered touchscreen\n"); 1149 return 0; 1150 } 1151 1152 static struct spi_driver ads7846_driver = { 1153 .driver = { 1154 .name = "ads7846", 1155 .bus = &spi_bus_type, 1156 .owner = THIS_MODULE, 1157 }, 1158 .probe = ads7846_probe, 1159 .remove = __devexit_p(ads7846_remove), 1160 .suspend = ads7846_suspend, 1161 .resume = ads7846_resume, 1162 }; 1163 1164 static int __init ads7846_init(void) 1165 { 1166 return spi_register_driver(&ads7846_driver); 1167 } 1168 module_init(ads7846_init); 1169 1170 static void __exit ads7846_exit(void) 1171 { 1172 spi_unregister_driver(&ads7846_driver); 1173 } 1174 module_exit(ads7846_exit); 1175 1176 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); 1177 MODULE_LICENSE("GPL"); 1178