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/gpio.h> 28 #include <linux/spi/spi.h> 29 #include <linux/spi/ads7846.h> 30 #include <asm/irq.h> 31 32 33 /* 34 * This code has been heavily tested on a Nokia 770, and lightly 35 * tested on other ads7846 devices (OSK/Mistral, Lubbock). 36 * TSC2046 is just newer ads7846 silicon. 37 * Support for ads7843 tested on Atmel at91sam926x-EK. 38 * Support for ads7845 has only been stubbed in. 39 * 40 * IRQ handling needs a workaround because of a shortcoming in handling 41 * edge triggered IRQs on some platforms like the OMAP1/2. These 42 * platforms don't handle the ARM lazy IRQ disabling properly, thus we 43 * have to maintain our own SW IRQ disabled status. This should be 44 * removed as soon as the affected platform's IRQ handling is fixed. 45 * 46 * app note sbaa036 talks in more detail about accurate sampling... 47 * that ought to help in situations like LCDs inducing noise (which 48 * can also be helped by using synch signals) and more generally. 49 * This driver tries to utilize the measures described in the app 50 * note. The strength of filtering can be set in the board-* specific 51 * files. 52 */ 53 54 #define TS_POLL_DELAY (1 * 1000000) /* ns delay before the first sample */ 55 #define TS_POLL_PERIOD (5 * 1000000) /* ns delay between samples */ 56 57 /* this driver doesn't aim at the peak continuous sample rate */ 58 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */) 59 60 struct ts_event { 61 /* For portability, we can't read 12 bit values using SPI (which 62 * would make the controller deliver them as native byteorder u16 63 * with msbs zeroed). Instead, we read them as two 8-bit values, 64 * *** WHICH NEED BYTESWAPPING *** and range adjustment. 65 */ 66 u16 x; 67 u16 y; 68 u16 z1, z2; 69 int ignore; 70 }; 71 72 /* 73 * We allocate this separately to avoid cache line sharing issues when 74 * driver is used with DMA-based SPI controllers (like atmel_spi) on 75 * systems where main memory is not DMA-coherent (most non-x86 boards). 76 */ 77 struct ads7846_packet { 78 u8 read_x, read_y, read_z1, read_z2, pwrdown; 79 u16 dummy; /* for the pwrdown read */ 80 struct ts_event tc; 81 }; 82 83 struct ads7846 { 84 struct input_dev *input; 85 char phys[32]; 86 87 struct spi_device *spi; 88 89 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 90 struct attribute_group *attr_group; 91 struct device *hwmon; 92 #endif 93 94 u16 model; 95 u16 vref_mv; 96 u16 vref_delay_usecs; 97 u16 x_plate_ohms; 98 u16 pressure_max; 99 100 struct ads7846_packet *packet; 101 102 struct spi_transfer xfer[18]; 103 struct spi_message msg[5]; 104 struct spi_message *last_msg; 105 int msg_idx; 106 int read_cnt; 107 int read_rep; 108 int last_read; 109 110 u16 debounce_max; 111 u16 debounce_tol; 112 u16 debounce_rep; 113 114 u16 penirq_recheck_delay_usecs; 115 116 spinlock_t lock; 117 struct hrtimer timer; 118 unsigned pendown:1; /* P: lock */ 119 unsigned pending:1; /* P: lock */ 120 // FIXME remove "irq_disabled" 121 unsigned irq_disabled:1; /* P: lock */ 122 unsigned disabled:1; 123 unsigned is_suspended:1; 124 125 int (*filter)(void *data, int data_idx, int *val); 126 void *filter_data; 127 void (*filter_cleanup)(void *data); 128 int (*get_pendown_state)(void); 129 int gpio_pendown; 130 }; 131 132 /* leave chip selected when we're done, for quicker re-select? */ 133 #if 0 134 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) 135 #else 136 #define CS_CHANGE(xfer) ((xfer).cs_change = 0) 137 #endif 138 139 /*--------------------------------------------------------------------------*/ 140 141 /* The ADS7846 has touchscreen and other sensors. 142 * Earlier ads784x chips are somewhat compatible. 143 */ 144 #define ADS_START (1 << 7) 145 #define ADS_A2A1A0_d_y (1 << 4) /* differential */ 146 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ 147 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ 148 #define ADS_A2A1A0_d_x (5 << 4) /* differential */ 149 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ 150 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ 151 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ 152 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ 153 #define ADS_8_BIT (1 << 3) 154 #define ADS_12_BIT (0 << 3) 155 #define ADS_SER (1 << 2) /* non-differential */ 156 #define ADS_DFR (0 << 2) /* differential */ 157 #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ 158 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ 159 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ 160 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ 161 162 #define MAX_12BIT ((1<<12)-1) 163 164 /* leave ADC powered up (disables penirq) between differential samples */ 165 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ 166 | ADS_12_BIT | ADS_DFR | \ 167 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) 168 169 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) 170 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) 171 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) 172 173 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) 174 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ 175 176 /* single-ended samples need to first power up reference voltage; 177 * we leave both ADC and VREF powered 178 */ 179 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ 180 | ADS_12_BIT | ADS_SER) 181 182 #define REF_ON (READ_12BIT_DFR(x, 1, 1)) 183 #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) 184 185 /*--------------------------------------------------------------------------*/ 186 187 /* 188 * Non-touchscreen sensors only use single-ended conversions. 189 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; 190 * ads7846 lets that pin be unconnected, to use internal vREF. 191 */ 192 193 struct ser_req { 194 u8 ref_on; 195 u8 command; 196 u8 ref_off; 197 u16 scratch; 198 __be16 sample; 199 struct spi_message msg; 200 struct spi_transfer xfer[6]; 201 }; 202 203 static void ads7846_enable(struct ads7846 *ts); 204 static void ads7846_disable(struct ads7846 *ts); 205 206 static int device_suspended(struct device *dev) 207 { 208 struct ads7846 *ts = dev_get_drvdata(dev); 209 return ts->is_suspended || ts->disabled; 210 } 211 212 static int ads7846_read12_ser(struct device *dev, unsigned command) 213 { 214 struct spi_device *spi = to_spi_device(dev); 215 struct ads7846 *ts = dev_get_drvdata(dev); 216 struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); 217 int status; 218 int use_internal; 219 220 if (!req) 221 return -ENOMEM; 222 223 spi_message_init(&req->msg); 224 225 /* FIXME boards with ads7846 might use external vref instead ... */ 226 use_internal = (ts->model == 7846); 227 228 /* maybe turn on internal vREF, and let it settle */ 229 if (use_internal) { 230 req->ref_on = REF_ON; 231 req->xfer[0].tx_buf = &req->ref_on; 232 req->xfer[0].len = 1; 233 spi_message_add_tail(&req->xfer[0], &req->msg); 234 235 req->xfer[1].rx_buf = &req->scratch; 236 req->xfer[1].len = 2; 237 238 /* for 1uF, settle for 800 usec; no cap, 100 usec. */ 239 req->xfer[1].delay_usecs = ts->vref_delay_usecs; 240 spi_message_add_tail(&req->xfer[1], &req->msg); 241 } 242 243 /* take sample */ 244 req->command = (u8) command; 245 req->xfer[2].tx_buf = &req->command; 246 req->xfer[2].len = 1; 247 spi_message_add_tail(&req->xfer[2], &req->msg); 248 249 req->xfer[3].rx_buf = &req->sample; 250 req->xfer[3].len = 2; 251 spi_message_add_tail(&req->xfer[3], &req->msg); 252 253 /* REVISIT: take a few more samples, and compare ... */ 254 255 /* converter in low power mode & enable PENIRQ */ 256 req->ref_off = PWRDOWN; 257 req->xfer[4].tx_buf = &req->ref_off; 258 req->xfer[4].len = 1; 259 spi_message_add_tail(&req->xfer[4], &req->msg); 260 261 req->xfer[5].rx_buf = &req->scratch; 262 req->xfer[5].len = 2; 263 CS_CHANGE(req->xfer[5]); 264 spi_message_add_tail(&req->xfer[5], &req->msg); 265 266 ts->irq_disabled = 1; 267 disable_irq(spi->irq); 268 status = spi_sync(spi, &req->msg); 269 ts->irq_disabled = 0; 270 enable_irq(spi->irq); 271 272 if (status == 0) { 273 /* on-wire is a must-ignore bit, a BE12 value, then padding */ 274 status = be16_to_cpu(req->sample); 275 status = status >> 3; 276 status &= 0x0fff; 277 } 278 279 kfree(req); 280 return status; 281 } 282 283 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 284 285 #define SHOW(name, var, adjust) static ssize_t \ 286 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 287 { \ 288 struct ads7846 *ts = dev_get_drvdata(dev); \ 289 ssize_t v = ads7846_read12_ser(dev, \ 290 READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \ 291 if (v < 0) \ 292 return v; \ 293 return sprintf(buf, "%u\n", adjust(ts, v)); \ 294 } \ 295 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); 296 297 298 /* Sysfs conventions report temperatures in millidegrees Celcius. 299 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high 300 * accuracy scheme without calibration data. For now we won't try either; 301 * userspace sees raw sensor values, and must scale/calibrate appropriately. 302 */ 303 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) 304 { 305 return v; 306 } 307 308 SHOW(temp0, temp0, null_adjust) /* temp1_input */ 309 SHOW(temp1, temp1, null_adjust) /* temp2_input */ 310 311 312 /* sysfs conventions report voltages in millivolts. We can convert voltages 313 * if we know vREF. userspace may need to scale vAUX to match the board's 314 * external resistors; we assume that vBATT only uses the internal ones. 315 */ 316 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 317 { 318 unsigned retval = v; 319 320 /* external resistors may scale vAUX into 0..vREF */ 321 retval *= ts->vref_mv; 322 retval = retval >> 12; 323 return retval; 324 } 325 326 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) 327 { 328 unsigned retval = vaux_adjust(ts, v); 329 330 /* ads7846 has a resistor ladder to scale this signal down */ 331 if (ts->model == 7846) 332 retval *= 4; 333 return retval; 334 } 335 336 SHOW(in0_input, vaux, vaux_adjust) 337 SHOW(in1_input, vbatt, vbatt_adjust) 338 339 340 static struct attribute *ads7846_attributes[] = { 341 &dev_attr_temp0.attr, 342 &dev_attr_temp1.attr, 343 &dev_attr_in0_input.attr, 344 &dev_attr_in1_input.attr, 345 NULL, 346 }; 347 348 static struct attribute_group ads7846_attr_group = { 349 .attrs = ads7846_attributes, 350 }; 351 352 static struct attribute *ads7843_attributes[] = { 353 &dev_attr_in0_input.attr, 354 &dev_attr_in1_input.attr, 355 NULL, 356 }; 357 358 static struct attribute_group ads7843_attr_group = { 359 .attrs = ads7843_attributes, 360 }; 361 362 static struct attribute *ads7845_attributes[] = { 363 &dev_attr_in0_input.attr, 364 NULL, 365 }; 366 367 static struct attribute_group ads7845_attr_group = { 368 .attrs = ads7845_attributes, 369 }; 370 371 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 372 { 373 struct device *hwmon; 374 int err; 375 376 /* hwmon sensors need a reference voltage */ 377 switch (ts->model) { 378 case 7846: 379 if (!ts->vref_mv) { 380 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); 381 ts->vref_mv = 2500; 382 } 383 break; 384 case 7845: 385 case 7843: 386 if (!ts->vref_mv) { 387 dev_warn(&spi->dev, 388 "external vREF for ADS%d not specified\n", 389 ts->model); 390 return 0; 391 } 392 break; 393 } 394 395 /* different chips have different sensor groups */ 396 switch (ts->model) { 397 case 7846: 398 ts->attr_group = &ads7846_attr_group; 399 break; 400 case 7845: 401 ts->attr_group = &ads7845_attr_group; 402 break; 403 case 7843: 404 ts->attr_group = &ads7843_attr_group; 405 break; 406 default: 407 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); 408 return 0; 409 } 410 411 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); 412 if (err) 413 return err; 414 415 hwmon = hwmon_device_register(&spi->dev); 416 if (IS_ERR(hwmon)) { 417 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 418 return PTR_ERR(hwmon); 419 } 420 421 ts->hwmon = hwmon; 422 return 0; 423 } 424 425 static void ads784x_hwmon_unregister(struct spi_device *spi, 426 struct ads7846 *ts) 427 { 428 if (ts->hwmon) { 429 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 430 hwmon_device_unregister(ts->hwmon); 431 } 432 } 433 434 #else 435 static inline int ads784x_hwmon_register(struct spi_device *spi, 436 struct ads7846 *ts) 437 { 438 return 0; 439 } 440 441 static inline void ads784x_hwmon_unregister(struct spi_device *spi, 442 struct ads7846 *ts) 443 { 444 } 445 #endif 446 447 static int is_pen_down(struct device *dev) 448 { 449 struct ads7846 *ts = dev_get_drvdata(dev); 450 451 return ts->pendown; 452 } 453 454 static ssize_t ads7846_pen_down_show(struct device *dev, 455 struct device_attribute *attr, char *buf) 456 { 457 return sprintf(buf, "%u\n", is_pen_down(dev)); 458 } 459 460 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); 461 462 static ssize_t ads7846_disable_show(struct device *dev, 463 struct device_attribute *attr, char *buf) 464 { 465 struct ads7846 *ts = dev_get_drvdata(dev); 466 467 return sprintf(buf, "%u\n", ts->disabled); 468 } 469 470 static ssize_t ads7846_disable_store(struct device *dev, 471 struct device_attribute *attr, 472 const char *buf, size_t count) 473 { 474 struct ads7846 *ts = dev_get_drvdata(dev); 475 long i; 476 477 if (strict_strtoul(buf, 10, &i)) 478 return -EINVAL; 479 480 spin_lock_irq(&ts->lock); 481 482 if (i) 483 ads7846_disable(ts); 484 else 485 ads7846_enable(ts); 486 487 spin_unlock_irq(&ts->lock); 488 489 return count; 490 } 491 492 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); 493 494 static struct attribute *ads784x_attributes[] = { 495 &dev_attr_pen_down.attr, 496 &dev_attr_disable.attr, 497 NULL, 498 }; 499 500 static struct attribute_group ads784x_attr_group = { 501 .attrs = ads784x_attributes, 502 }; 503 504 /*--------------------------------------------------------------------------*/ 505 506 static int get_pendown_state(struct ads7846 *ts) 507 { 508 if (ts->get_pendown_state) 509 return ts->get_pendown_state(); 510 511 return !gpio_get_value(ts->gpio_pendown); 512 } 513 514 /* 515 * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, 516 * to retrieve touchscreen status. 517 * 518 * The SPI transfer completion callback does the real work. It reports 519 * touchscreen events and reactivates the timer (or IRQ) as appropriate. 520 */ 521 522 static void ads7846_rx(void *ads) 523 { 524 struct ads7846 *ts = ads; 525 struct ads7846_packet *packet = ts->packet; 526 unsigned Rt; 527 u16 x, y, z1, z2; 528 529 /* ads7846_rx_val() did in-place conversion (including byteswap) from 530 * on-the-wire format as part of debouncing to get stable readings. 531 */ 532 x = packet->tc.x; 533 y = packet->tc.y; 534 z1 = packet->tc.z1; 535 z2 = packet->tc.z2; 536 537 /* range filtering */ 538 if (x == MAX_12BIT) 539 x = 0; 540 541 if (ts->model == 7843) { 542 Rt = ts->pressure_max / 2; 543 } else if (likely(x && z1)) { 544 /* compute touch pressure resistance using equation #2 */ 545 Rt = z2; 546 Rt -= z1; 547 Rt *= x; 548 Rt *= ts->x_plate_ohms; 549 Rt /= z1; 550 Rt = (Rt + 2047) >> 12; 551 } else { 552 Rt = 0; 553 } 554 555 /* Sample found inconsistent by debouncing or pressure is beyond 556 * the maximum. Don't report it to user space, repeat at least 557 * once more the measurement 558 */ 559 if (packet->tc.ignore || Rt > ts->pressure_max) { 560 #ifdef VERBOSE 561 pr_debug("%s: ignored %d pressure %d\n", 562 dev_name(&ts->spi->dev), packet->tc.ignore, Rt); 563 #endif 564 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 565 HRTIMER_MODE_REL); 566 return; 567 } 568 569 /* Maybe check the pendown state before reporting. This discards 570 * false readings when the pen is lifted. 571 */ 572 if (ts->penirq_recheck_delay_usecs) { 573 udelay(ts->penirq_recheck_delay_usecs); 574 if (!get_pendown_state(ts)) 575 Rt = 0; 576 } 577 578 /* NOTE: We can't rely on the pressure to determine the pen down 579 * state, even this controller has a pressure sensor. The pressure 580 * value can fluctuate for quite a while after lifting the pen and 581 * in some cases may not even settle at the expected value. 582 * 583 * The only safe way to check for the pen up condition is in the 584 * timer by reading the pen signal state (it's a GPIO _and_ IRQ). 585 */ 586 if (Rt) { 587 struct input_dev *input = ts->input; 588 589 if (!ts->pendown) { 590 input_report_key(input, BTN_TOUCH, 1); 591 ts->pendown = 1; 592 #ifdef VERBOSE 593 dev_dbg(&ts->spi->dev, "DOWN\n"); 594 #endif 595 } 596 input_report_abs(input, ABS_X, x); 597 input_report_abs(input, ABS_Y, y); 598 input_report_abs(input, ABS_PRESSURE, Rt); 599 600 input_sync(input); 601 #ifdef VERBOSE 602 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); 603 #endif 604 } 605 606 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 607 HRTIMER_MODE_REL); 608 } 609 610 static int ads7846_debounce(void *ads, int data_idx, int *val) 611 { 612 struct ads7846 *ts = ads; 613 614 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { 615 /* Start over collecting consistent readings. */ 616 ts->read_rep = 0; 617 /* Repeat it, if this was the first read or the read 618 * wasn't consistent enough. */ 619 if (ts->read_cnt < ts->debounce_max) { 620 ts->last_read = *val; 621 ts->read_cnt++; 622 return ADS7846_FILTER_REPEAT; 623 } else { 624 /* Maximum number of debouncing reached and still 625 * not enough number of consistent readings. Abort 626 * the whole sample, repeat it in the next sampling 627 * period. 628 */ 629 ts->read_cnt = 0; 630 return ADS7846_FILTER_IGNORE; 631 } 632 } else { 633 if (++ts->read_rep > ts->debounce_rep) { 634 /* Got a good reading for this coordinate, 635 * go for the next one. */ 636 ts->read_cnt = 0; 637 ts->read_rep = 0; 638 return ADS7846_FILTER_OK; 639 } else { 640 /* Read more values that are consistent. */ 641 ts->read_cnt++; 642 return ADS7846_FILTER_REPEAT; 643 } 644 } 645 } 646 647 static int ads7846_no_filter(void *ads, int data_idx, int *val) 648 { 649 return ADS7846_FILTER_OK; 650 } 651 652 static void ads7846_rx_val(void *ads) 653 { 654 struct ads7846 *ts = ads; 655 struct ads7846_packet *packet = ts->packet; 656 struct spi_message *m; 657 struct spi_transfer *t; 658 int val; 659 int action; 660 int status; 661 662 m = &ts->msg[ts->msg_idx]; 663 t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 664 665 /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; 666 * built from two 8 bit values written msb-first. 667 */ 668 val = be16_to_cpup((__be16 *)t->rx_buf) >> 3; 669 670 action = ts->filter(ts->filter_data, ts->msg_idx, &val); 671 switch (action) { 672 case ADS7846_FILTER_REPEAT: 673 break; 674 case ADS7846_FILTER_IGNORE: 675 packet->tc.ignore = 1; 676 /* Last message will contain ads7846_rx() as the 677 * completion function. 678 */ 679 m = ts->last_msg; 680 break; 681 case ADS7846_FILTER_OK: 682 *(u16 *)t->rx_buf = val; 683 packet->tc.ignore = 0; 684 m = &ts->msg[++ts->msg_idx]; 685 break; 686 default: 687 BUG(); 688 } 689 status = spi_async(ts->spi, m); 690 if (status) 691 dev_err(&ts->spi->dev, "spi_async --> %d\n", 692 status); 693 } 694 695 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle) 696 { 697 struct ads7846 *ts = container_of(handle, struct ads7846, timer); 698 int status = 0; 699 700 spin_lock_irq(&ts->lock); 701 702 if (unlikely(!get_pendown_state(ts) || 703 device_suspended(&ts->spi->dev))) { 704 if (ts->pendown) { 705 struct input_dev *input = ts->input; 706 707 input_report_key(input, BTN_TOUCH, 0); 708 input_report_abs(input, ABS_PRESSURE, 0); 709 input_sync(input); 710 711 ts->pendown = 0; 712 #ifdef VERBOSE 713 dev_dbg(&ts->spi->dev, "UP\n"); 714 #endif 715 } 716 717 /* measurement cycle ended */ 718 if (!device_suspended(&ts->spi->dev)) { 719 ts->irq_disabled = 0; 720 enable_irq(ts->spi->irq); 721 } 722 ts->pending = 0; 723 } else { 724 /* pen is still down, continue with the measurement */ 725 ts->msg_idx = 0; 726 status = spi_async(ts->spi, &ts->msg[0]); 727 if (status) 728 dev_err(&ts->spi->dev, "spi_async --> %d\n", status); 729 } 730 731 spin_unlock_irq(&ts->lock); 732 return HRTIMER_NORESTART; 733 } 734 735 static irqreturn_t ads7846_irq(int irq, void *handle) 736 { 737 struct ads7846 *ts = handle; 738 unsigned long flags; 739 740 spin_lock_irqsave(&ts->lock, flags); 741 if (likely(get_pendown_state(ts))) { 742 if (!ts->irq_disabled) { 743 /* The ARM do_simple_IRQ() dispatcher doesn't act 744 * like the other dispatchers: it will report IRQs 745 * even after they've been disabled. We work around 746 * that here. (The "generic irq" framework may help...) 747 */ 748 ts->irq_disabled = 1; 749 disable_irq(ts->spi->irq); 750 ts->pending = 1; 751 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY), 752 HRTIMER_MODE_REL); 753 } 754 } 755 spin_unlock_irqrestore(&ts->lock, flags); 756 757 return IRQ_HANDLED; 758 } 759 760 /*--------------------------------------------------------------------------*/ 761 762 /* Must be called with ts->lock held */ 763 static void ads7846_disable(struct ads7846 *ts) 764 { 765 if (ts->disabled) 766 return; 767 768 ts->disabled = 1; 769 770 /* are we waiting for IRQ, or polling? */ 771 if (!ts->pending) { 772 ts->irq_disabled = 1; 773 disable_irq(ts->spi->irq); 774 } else { 775 /* the timer will run at least once more, and 776 * leave everything in a clean state, IRQ disabled 777 */ 778 while (ts->pending) { 779 spin_unlock_irq(&ts->lock); 780 msleep(1); 781 spin_lock_irq(&ts->lock); 782 } 783 } 784 785 /* we know the chip's in lowpower mode since we always 786 * leave it that way after every request 787 */ 788 } 789 790 /* Must be called with ts->lock held */ 791 static void ads7846_enable(struct ads7846 *ts) 792 { 793 if (!ts->disabled) 794 return; 795 796 ts->disabled = 0; 797 ts->irq_disabled = 0; 798 enable_irq(ts->spi->irq); 799 } 800 801 static int ads7846_suspend(struct spi_device *spi, pm_message_t message) 802 { 803 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 804 805 spin_lock_irq(&ts->lock); 806 807 ts->is_suspended = 1; 808 ads7846_disable(ts); 809 810 spin_unlock_irq(&ts->lock); 811 812 return 0; 813 814 } 815 816 static int ads7846_resume(struct spi_device *spi) 817 { 818 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 819 820 spin_lock_irq(&ts->lock); 821 822 ts->is_suspended = 0; 823 ads7846_enable(ts); 824 825 spin_unlock_irq(&ts->lock); 826 827 return 0; 828 } 829 830 static int __devinit setup_pendown(struct spi_device *spi, struct ads7846 *ts) 831 { 832 struct ads7846_platform_data *pdata = spi->dev.platform_data; 833 int err; 834 835 /* REVISIT when the irq can be triggered active-low, or if for some 836 * reason the touchscreen isn't hooked up, we don't need to access 837 * the pendown state. 838 */ 839 if (!pdata->get_pendown_state && !gpio_is_valid(pdata->gpio_pendown)) { 840 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n"); 841 return -EINVAL; 842 } 843 844 if (pdata->get_pendown_state) { 845 ts->get_pendown_state = pdata->get_pendown_state; 846 return 0; 847 } 848 849 err = gpio_request(pdata->gpio_pendown, "ads7846_pendown"); 850 if (err) { 851 dev_err(&spi->dev, "failed to request pendown GPIO%d\n", 852 pdata->gpio_pendown); 853 return err; 854 } 855 856 ts->gpio_pendown = pdata->gpio_pendown; 857 return 0; 858 } 859 860 static int __devinit ads7846_probe(struct spi_device *spi) 861 { 862 struct ads7846 *ts; 863 struct ads7846_packet *packet; 864 struct input_dev *input_dev; 865 struct ads7846_platform_data *pdata = spi->dev.platform_data; 866 struct spi_message *m; 867 struct spi_transfer *x; 868 int vref; 869 int err; 870 871 if (!spi->irq) { 872 dev_dbg(&spi->dev, "no IRQ?\n"); 873 return -ENODEV; 874 } 875 876 if (!pdata) { 877 dev_dbg(&spi->dev, "no platform data?\n"); 878 return -ENODEV; 879 } 880 881 /* don't exceed max specified sample rate */ 882 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { 883 dev_dbg(&spi->dev, "f(sample) %d KHz?\n", 884 (spi->max_speed_hz/SAMPLE_BITS)/1000); 885 return -EINVAL; 886 } 887 888 /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except 889 * that even if the hardware can do that, the SPI controller driver 890 * may not. So we stick to very-portable 8 bit words, both RX and TX. 891 */ 892 spi->bits_per_word = 8; 893 spi->mode = SPI_MODE_0; 894 err = spi_setup(spi); 895 if (err < 0) 896 return err; 897 898 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); 899 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL); 900 input_dev = input_allocate_device(); 901 if (!ts || !packet || !input_dev) { 902 err = -ENOMEM; 903 goto err_free_mem; 904 } 905 906 dev_set_drvdata(&spi->dev, ts); 907 908 ts->packet = packet; 909 ts->spi = spi; 910 ts->input = input_dev; 911 ts->vref_mv = pdata->vref_mv; 912 913 hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 914 ts->timer.function = ads7846_timer; 915 916 spin_lock_init(&ts->lock); 917 918 ts->model = pdata->model ? : 7846; 919 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; 920 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; 921 ts->pressure_max = pdata->pressure_max ? : ~0; 922 923 if (pdata->filter != NULL) { 924 if (pdata->filter_init != NULL) { 925 err = pdata->filter_init(pdata, &ts->filter_data); 926 if (err < 0) 927 goto err_free_mem; 928 } 929 ts->filter = pdata->filter; 930 ts->filter_cleanup = pdata->filter_cleanup; 931 } else if (pdata->debounce_max) { 932 ts->debounce_max = pdata->debounce_max; 933 if (ts->debounce_max < 2) 934 ts->debounce_max = 2; 935 ts->debounce_tol = pdata->debounce_tol; 936 ts->debounce_rep = pdata->debounce_rep; 937 ts->filter = ads7846_debounce; 938 ts->filter_data = ts; 939 } else 940 ts->filter = ads7846_no_filter; 941 942 err = setup_pendown(spi, ts); 943 if (err) 944 goto err_cleanup_filter; 945 946 if (pdata->penirq_recheck_delay_usecs) 947 ts->penirq_recheck_delay_usecs = 948 pdata->penirq_recheck_delay_usecs; 949 950 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev)); 951 952 input_dev->name = "ADS784x Touchscreen"; 953 input_dev->phys = ts->phys; 954 input_dev->dev.parent = &spi->dev; 955 956 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 957 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 958 input_set_abs_params(input_dev, ABS_X, 959 pdata->x_min ? : 0, 960 pdata->x_max ? : MAX_12BIT, 961 0, 0); 962 input_set_abs_params(input_dev, ABS_Y, 963 pdata->y_min ? : 0, 964 pdata->y_max ? : MAX_12BIT, 965 0, 0); 966 input_set_abs_params(input_dev, ABS_PRESSURE, 967 pdata->pressure_min, pdata->pressure_max, 0, 0); 968 969 vref = pdata->keep_vref_on; 970 971 /* set up the transfers to read touchscreen state; this assumes we 972 * use formula #2 for pressure, not #3. 973 */ 974 m = &ts->msg[0]; 975 x = ts->xfer; 976 977 spi_message_init(m); 978 979 /* y- still on; turn on only y+ (and ADC) */ 980 packet->read_y = READ_Y(vref); 981 x->tx_buf = &packet->read_y; 982 x->len = 1; 983 spi_message_add_tail(x, m); 984 985 x++; 986 x->rx_buf = &packet->tc.y; 987 x->len = 2; 988 spi_message_add_tail(x, m); 989 990 /* the first sample after switching drivers can be low quality; 991 * optionally discard it, using a second one after the signals 992 * have had enough time to stabilize. 993 */ 994 if (pdata->settle_delay_usecs) { 995 x->delay_usecs = pdata->settle_delay_usecs; 996 997 x++; 998 x->tx_buf = &packet->read_y; 999 x->len = 1; 1000 spi_message_add_tail(x, m); 1001 1002 x++; 1003 x->rx_buf = &packet->tc.y; 1004 x->len = 2; 1005 spi_message_add_tail(x, m); 1006 } 1007 1008 m->complete = ads7846_rx_val; 1009 m->context = ts; 1010 1011 m++; 1012 spi_message_init(m); 1013 1014 /* turn y- off, x+ on, then leave in lowpower */ 1015 x++; 1016 packet->read_x = READ_X(vref); 1017 x->tx_buf = &packet->read_x; 1018 x->len = 1; 1019 spi_message_add_tail(x, m); 1020 1021 x++; 1022 x->rx_buf = &packet->tc.x; 1023 x->len = 2; 1024 spi_message_add_tail(x, m); 1025 1026 /* ... maybe discard first sample ... */ 1027 if (pdata->settle_delay_usecs) { 1028 x->delay_usecs = pdata->settle_delay_usecs; 1029 1030 x++; 1031 x->tx_buf = &packet->read_x; 1032 x->len = 1; 1033 spi_message_add_tail(x, m); 1034 1035 x++; 1036 x->rx_buf = &packet->tc.x; 1037 x->len = 2; 1038 spi_message_add_tail(x, m); 1039 } 1040 1041 m->complete = ads7846_rx_val; 1042 m->context = ts; 1043 1044 /* turn y+ off, x- on; we'll use formula #2 */ 1045 if (ts->model == 7846) { 1046 m++; 1047 spi_message_init(m); 1048 1049 x++; 1050 packet->read_z1 = READ_Z1(vref); 1051 x->tx_buf = &packet->read_z1; 1052 x->len = 1; 1053 spi_message_add_tail(x, m); 1054 1055 x++; 1056 x->rx_buf = &packet->tc.z1; 1057 x->len = 2; 1058 spi_message_add_tail(x, m); 1059 1060 /* ... maybe discard first sample ... */ 1061 if (pdata->settle_delay_usecs) { 1062 x->delay_usecs = pdata->settle_delay_usecs; 1063 1064 x++; 1065 x->tx_buf = &packet->read_z1; 1066 x->len = 1; 1067 spi_message_add_tail(x, m); 1068 1069 x++; 1070 x->rx_buf = &packet->tc.z1; 1071 x->len = 2; 1072 spi_message_add_tail(x, m); 1073 } 1074 1075 m->complete = ads7846_rx_val; 1076 m->context = ts; 1077 1078 m++; 1079 spi_message_init(m); 1080 1081 x++; 1082 packet->read_z2 = READ_Z2(vref); 1083 x->tx_buf = &packet->read_z2; 1084 x->len = 1; 1085 spi_message_add_tail(x, m); 1086 1087 x++; 1088 x->rx_buf = &packet->tc.z2; 1089 x->len = 2; 1090 spi_message_add_tail(x, m); 1091 1092 /* ... maybe discard first sample ... */ 1093 if (pdata->settle_delay_usecs) { 1094 x->delay_usecs = pdata->settle_delay_usecs; 1095 1096 x++; 1097 x->tx_buf = &packet->read_z2; 1098 x->len = 1; 1099 spi_message_add_tail(x, m); 1100 1101 x++; 1102 x->rx_buf = &packet->tc.z2; 1103 x->len = 2; 1104 spi_message_add_tail(x, m); 1105 } 1106 1107 m->complete = ads7846_rx_val; 1108 m->context = ts; 1109 } 1110 1111 /* power down */ 1112 m++; 1113 spi_message_init(m); 1114 1115 x++; 1116 packet->pwrdown = PWRDOWN; 1117 x->tx_buf = &packet->pwrdown; 1118 x->len = 1; 1119 spi_message_add_tail(x, m); 1120 1121 x++; 1122 x->rx_buf = &packet->dummy; 1123 x->len = 2; 1124 CS_CHANGE(*x); 1125 spi_message_add_tail(x, m); 1126 1127 m->complete = ads7846_rx; 1128 m->context = ts; 1129 1130 ts->last_msg = m; 1131 1132 if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, 1133 spi->dev.driver->name, ts)) { 1134 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); 1135 err = -EBUSY; 1136 goto err_free_gpio; 1137 } 1138 1139 err = ads784x_hwmon_register(spi, ts); 1140 if (err) 1141 goto err_free_irq; 1142 1143 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); 1144 1145 /* take a first sample, leaving nPENIRQ active and vREF off; avoid 1146 * the touchscreen, in case it's not connected. 1147 */ 1148 (void) ads7846_read12_ser(&spi->dev, 1149 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); 1150 1151 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); 1152 if (err) 1153 goto err_remove_hwmon; 1154 1155 err = input_register_device(input_dev); 1156 if (err) 1157 goto err_remove_attr_group; 1158 1159 return 0; 1160 1161 err_remove_attr_group: 1162 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1163 err_remove_hwmon: 1164 ads784x_hwmon_unregister(spi, ts); 1165 err_free_irq: 1166 free_irq(spi->irq, ts); 1167 err_free_gpio: 1168 if (ts->gpio_pendown != -1) 1169 gpio_free(ts->gpio_pendown); 1170 err_cleanup_filter: 1171 if (ts->filter_cleanup) 1172 ts->filter_cleanup(ts->filter_data); 1173 err_free_mem: 1174 input_free_device(input_dev); 1175 kfree(packet); 1176 kfree(ts); 1177 return err; 1178 } 1179 1180 static int __devexit ads7846_remove(struct spi_device *spi) 1181 { 1182 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 1183 1184 ads784x_hwmon_unregister(spi, ts); 1185 input_unregister_device(ts->input); 1186 1187 ads7846_suspend(spi, PMSG_SUSPEND); 1188 1189 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1190 1191 free_irq(ts->spi->irq, ts); 1192 /* suspend left the IRQ disabled */ 1193 enable_irq(ts->spi->irq); 1194 1195 if (ts->gpio_pendown != -1) 1196 gpio_free(ts->gpio_pendown); 1197 1198 if (ts->filter_cleanup) 1199 ts->filter_cleanup(ts->filter_data); 1200 1201 kfree(ts->packet); 1202 kfree(ts); 1203 1204 dev_dbg(&spi->dev, "unregistered touchscreen\n"); 1205 return 0; 1206 } 1207 1208 static struct spi_driver ads7846_driver = { 1209 .driver = { 1210 .name = "ads7846", 1211 .bus = &spi_bus_type, 1212 .owner = THIS_MODULE, 1213 }, 1214 .probe = ads7846_probe, 1215 .remove = __devexit_p(ads7846_remove), 1216 .suspend = ads7846_suspend, 1217 .resume = ads7846_resume, 1218 }; 1219 1220 static int __init ads7846_init(void) 1221 { 1222 return spi_register_driver(&ads7846_driver); 1223 } 1224 module_init(ads7846_init); 1225 1226 static void __exit ads7846_exit(void) 1227 { 1228 spi_unregister_driver(&ads7846_driver); 1229 } 1230 module_exit(ads7846_exit); 1231 1232 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); 1233 MODULE_LICENSE("GPL"); 1234