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 #ifdef CONFIG_ARM 32 #include <asm/mach-types.h> 33 #ifdef CONFIG_ARCH_OMAP 34 #include <asm/arch/gpio.h> 35 #endif 36 #endif 37 38 39 /* 40 * This code has been heavily tested on a Nokia 770, and lightly 41 * tested on other ads7846 devices (OSK/Mistral, Lubbock). 42 * Support for ads7843 tested on Atmel at91sam926x-EK. 43 * Support for ads7845 has only been stubbed in. 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 * 1000000) /* ns delay before the first sample */ 60 #define TS_POLL_PERIOD (5 * 1000000) /* ns 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 /* For portability, we can't read 12 bit values using SPI (which 67 * would make the controller deliver them as native byteorder u16 68 * with msbs zeroed). Instead, we read them as two 8-bit values, 69 * *** WHICH NEED BYTESWAPPING *** and range adjustment. 70 */ 71 u16 x; 72 u16 y; 73 u16 z1, z2; 74 int ignore; 75 }; 76 77 struct ads7846 { 78 struct input_dev *input; 79 char phys[32]; 80 81 struct spi_device *spi; 82 83 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 84 struct attribute_group *attr_group; 85 struct class_device *hwmon; 86 #endif 87 88 u16 model; 89 u16 vref_delay_usecs; 90 u16 x_plate_ohms; 91 u16 pressure_max; 92 93 u8 read_x, read_y, read_z1, read_z2, pwrdown; 94 u16 dummy; /* for the pwrdown read */ 95 struct ts_event tc; 96 97 struct spi_transfer xfer[10]; 98 struct spi_message msg[5]; 99 struct spi_message *last_msg; 100 int msg_idx; 101 int read_cnt; 102 int read_rep; 103 int last_read; 104 105 u16 debounce_max; 106 u16 debounce_tol; 107 u16 debounce_rep; 108 109 spinlock_t lock; 110 struct hrtimer timer; 111 unsigned pendown:1; /* P: lock */ 112 unsigned pending:1; /* P: lock */ 113 // FIXME remove "irq_disabled" 114 unsigned irq_disabled:1; /* P: lock */ 115 unsigned disabled:1; 116 117 int (*filter)(void *data, int data_idx, int *val); 118 void *filter_data; 119 void (*filter_cleanup)(void *data); 120 int (*get_pendown_state)(void); 121 }; 122 123 /* leave chip selected when we're done, for quicker re-select? */ 124 #if 0 125 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) 126 #else 127 #define CS_CHANGE(xfer) ((xfer).cs_change = 0) 128 #endif 129 130 /*--------------------------------------------------------------------------*/ 131 132 /* The ADS7846 has touchscreen and other sensors. 133 * Earlier ads784x chips are somewhat compatible. 134 */ 135 #define ADS_START (1 << 7) 136 #define ADS_A2A1A0_d_y (1 << 4) /* differential */ 137 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ 138 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ 139 #define ADS_A2A1A0_d_x (5 << 4) /* differential */ 140 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ 141 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ 142 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ 143 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ 144 #define ADS_8_BIT (1 << 3) 145 #define ADS_12_BIT (0 << 3) 146 #define ADS_SER (1 << 2) /* non-differential */ 147 #define ADS_DFR (0 << 2) /* differential */ 148 #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ 149 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ 150 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ 151 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ 152 153 #define MAX_12BIT ((1<<12)-1) 154 155 /* leave ADC powered up (disables penirq) between differential samples */ 156 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ 157 | ADS_12_BIT | ADS_DFR | \ 158 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) 159 160 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) 161 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) 162 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) 163 164 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) 165 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ 166 167 /* single-ended samples need to first power up reference voltage; 168 * we leave both ADC and VREF powered 169 */ 170 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ 171 | ADS_12_BIT | ADS_SER) 172 173 #define REF_ON (READ_12BIT_DFR(x, 1, 1)) 174 #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) 175 176 /*--------------------------------------------------------------------------*/ 177 178 /* 179 * Non-touchscreen sensors only use single-ended conversions. 180 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; 181 * ads7846 lets that pin be unconnected, to use internal vREF. 182 */ 183 static unsigned vREF_mV; 184 module_param(vREF_mV, uint, 0); 185 MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts"); 186 187 struct ser_req { 188 u8 ref_on; 189 u8 command; 190 u8 ref_off; 191 u16 scratch; 192 __be16 sample; 193 struct spi_message msg; 194 struct spi_transfer xfer[6]; 195 }; 196 197 static void ads7846_enable(struct ads7846 *ts); 198 static void ads7846_disable(struct ads7846 *ts); 199 200 static int device_suspended(struct device *dev) 201 { 202 struct ads7846 *ts = dev_get_drvdata(dev); 203 return dev->power.power_state.event != PM_EVENT_ON || ts->disabled; 204 } 205 206 static int ads7846_read12_ser(struct device *dev, unsigned command) 207 { 208 struct spi_device *spi = to_spi_device(dev); 209 struct ads7846 *ts = dev_get_drvdata(dev); 210 struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); 211 int status; 212 int sample; 213 int use_internal; 214 215 if (!req) 216 return -ENOMEM; 217 218 spi_message_init(&req->msg); 219 220 /* FIXME boards with ads7846 might use external vref instead ... */ 221 use_internal = (ts->model == 7846); 222 223 /* maybe turn on internal vREF, and let it settle */ 224 if (use_internal) { 225 req->ref_on = REF_ON; 226 req->xfer[0].tx_buf = &req->ref_on; 227 req->xfer[0].len = 1; 228 spi_message_add_tail(&req->xfer[0], &req->msg); 229 230 req->xfer[1].rx_buf = &req->scratch; 231 req->xfer[1].len = 2; 232 233 /* for 1uF, settle for 800 usec; no cap, 100 usec. */ 234 req->xfer[1].delay_usecs = ts->vref_delay_usecs; 235 spi_message_add_tail(&req->xfer[1], &req->msg); 236 } 237 238 /* take sample */ 239 req->command = (u8) command; 240 req->xfer[2].tx_buf = &req->command; 241 req->xfer[2].len = 1; 242 spi_message_add_tail(&req->xfer[2], &req->msg); 243 244 req->xfer[3].rx_buf = &req->sample; 245 req->xfer[3].len = 2; 246 spi_message_add_tail(&req->xfer[3], &req->msg); 247 248 /* REVISIT: take a few more samples, and compare ... */ 249 250 /* converter in low power mode & enable PENIRQ */ 251 req->ref_off = PWRDOWN; 252 req->xfer[4].tx_buf = &req->ref_off; 253 req->xfer[4].len = 1; 254 spi_message_add_tail(&req->xfer[4], &req->msg); 255 256 req->xfer[5].rx_buf = &req->scratch; 257 req->xfer[5].len = 2; 258 CS_CHANGE(req->xfer[5]); 259 spi_message_add_tail(&req->xfer[5], &req->msg); 260 261 ts->irq_disabled = 1; 262 disable_irq(spi->irq); 263 status = spi_sync(spi, &req->msg); 264 ts->irq_disabled = 0; 265 enable_irq(spi->irq); 266 267 if (req->msg.status) 268 status = req->msg.status; 269 270 /* on-wire is a must-ignore bit, a BE12 value, then padding */ 271 sample = be16_to_cpu(req->sample); 272 sample = sample >> 3; 273 sample &= 0x0fff; 274 275 kfree(req); 276 return status ? status : sample; 277 } 278 279 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 280 281 #define SHOW(name, var, adjust) static ssize_t \ 282 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 283 { \ 284 struct ads7846 *ts = dev_get_drvdata(dev); \ 285 ssize_t v = ads7846_read12_ser(dev, \ 286 READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \ 287 if (v < 0) \ 288 return v; \ 289 return sprintf(buf, "%u\n", adjust(ts, v)); \ 290 } \ 291 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); 292 293 294 /* Sysfs conventions report temperatures in millidegrees Celcius. 295 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high 296 * accuracy scheme without calibration data. For now we won't try either; 297 * userspace sees raw sensor values, and must scale/calibrate appropriately. 298 */ 299 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) 300 { 301 return v; 302 } 303 304 SHOW(temp0, temp0, null_adjust) /* temp1_input */ 305 SHOW(temp1, temp1, null_adjust) /* temp2_input */ 306 307 308 /* sysfs conventions report voltages in millivolts. We can convert voltages 309 * if we know vREF. userspace may need to scale vAUX to match the board's 310 * external resistors; we assume that vBATT only uses the internal ones. 311 */ 312 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 313 { 314 unsigned retval = v; 315 316 /* external resistors may scale vAUX into 0..vREF */ 317 retval *= vREF_mV; 318 retval = retval >> 12; 319 return retval; 320 } 321 322 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) 323 { 324 unsigned retval = vaux_adjust(ts, v); 325 326 /* ads7846 has a resistor ladder to scale this signal down */ 327 if (ts->model == 7846) 328 retval *= 4; 329 return retval; 330 } 331 332 SHOW(in0_input, vaux, vaux_adjust) 333 SHOW(in1_input, vbatt, vbatt_adjust) 334 335 336 static struct attribute *ads7846_attributes[] = { 337 &dev_attr_temp0.attr, 338 &dev_attr_temp1.attr, 339 &dev_attr_in0_input.attr, 340 &dev_attr_in1_input.attr, 341 NULL, 342 }; 343 344 static struct attribute_group ads7846_attr_group = { 345 .attrs = ads7846_attributes, 346 }; 347 348 static struct attribute *ads7843_attributes[] = { 349 &dev_attr_in0_input.attr, 350 &dev_attr_in1_input.attr, 351 NULL, 352 }; 353 354 static struct attribute_group ads7843_attr_group = { 355 .attrs = ads7843_attributes, 356 }; 357 358 static struct attribute *ads7845_attributes[] = { 359 &dev_attr_in0_input.attr, 360 NULL, 361 }; 362 363 static struct attribute_group ads7845_attr_group = { 364 .attrs = ads7845_attributes, 365 }; 366 367 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 368 { 369 struct class_device *hwmon; 370 int err; 371 372 /* hwmon sensors need a reference voltage */ 373 switch (ts->model) { 374 case 7846: 375 if (!vREF_mV) { 376 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); 377 vREF_mV = 2500; 378 } 379 break; 380 case 7845: 381 case 7843: 382 if (!vREF_mV) { 383 dev_warn(&spi->dev, 384 "external vREF for ADS%d not specified\n", 385 ts->model); 386 return 0; 387 } 388 break; 389 } 390 391 /* different chips have different sensor groups */ 392 switch (ts->model) { 393 case 7846: 394 ts->attr_group = &ads7846_attr_group; 395 break; 396 case 7845: 397 ts->attr_group = &ads7845_attr_group; 398 break; 399 case 7843: 400 ts->attr_group = &ads7843_attr_group; 401 break; 402 default: 403 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); 404 return 0; 405 } 406 407 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); 408 if (err) 409 return err; 410 411 hwmon = hwmon_device_register(&spi->dev); 412 if (IS_ERR(hwmon)) { 413 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 414 return PTR_ERR(hwmon); 415 } 416 417 ts->hwmon = hwmon; 418 return 0; 419 } 420 421 static void ads784x_hwmon_unregister(struct spi_device *spi, 422 struct ads7846 *ts) 423 { 424 if (ts->hwmon) { 425 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 426 hwmon_device_unregister(ts->hwmon); 427 } 428 } 429 430 #else 431 static inline int ads784x_hwmon_register(struct spi_device *spi, 432 struct ads7846 *ts) 433 { 434 return 0; 435 } 436 437 static inline void ads784x_hwmon_unregister(struct spi_device *spi, 438 struct ads7846 *ts) 439 { 440 } 441 #endif 442 443 static int is_pen_down(struct device *dev) 444 { 445 struct ads7846 *ts = dev_get_drvdata(dev); 446 447 return ts->pendown; 448 } 449 450 static ssize_t ads7846_pen_down_show(struct device *dev, 451 struct device_attribute *attr, char *buf) 452 { 453 return sprintf(buf, "%u\n", is_pen_down(dev)); 454 } 455 456 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); 457 458 static ssize_t ads7846_disable_show(struct device *dev, 459 struct device_attribute *attr, char *buf) 460 { 461 struct ads7846 *ts = dev_get_drvdata(dev); 462 463 return sprintf(buf, "%u\n", ts->disabled); 464 } 465 466 static ssize_t ads7846_disable_store(struct device *dev, 467 struct device_attribute *attr, 468 const char *buf, size_t count) 469 { 470 struct ads7846 *ts = dev_get_drvdata(dev); 471 char *endp; 472 int i; 473 474 i = simple_strtoul(buf, &endp, 10); 475 spin_lock_irq(&ts->lock); 476 477 if (i) 478 ads7846_disable(ts); 479 else 480 ads7846_enable(ts); 481 482 spin_unlock_irq(&ts->lock); 483 484 return count; 485 } 486 487 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); 488 489 static struct attribute *ads784x_attributes[] = { 490 &dev_attr_pen_down.attr, 491 &dev_attr_disable.attr, 492 NULL, 493 }; 494 495 static struct attribute_group ads784x_attr_group = { 496 .attrs = ads784x_attributes, 497 }; 498 499 /*--------------------------------------------------------------------------*/ 500 501 /* 502 * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, 503 * to retrieve touchscreen status. 504 * 505 * The SPI transfer completion callback does the real work. It reports 506 * touchscreen events and reactivates the timer (or IRQ) as appropriate. 507 */ 508 509 static void ads7846_rx(void *ads) 510 { 511 struct ads7846 *ts = ads; 512 unsigned Rt; 513 u16 x, y, z1, z2; 514 515 /* ads7846_rx_val() did in-place conversion (including byteswap) from 516 * on-the-wire format as part of debouncing to get stable readings. 517 */ 518 x = ts->tc.x; 519 y = ts->tc.y; 520 z1 = ts->tc.z1; 521 z2 = ts->tc.z2; 522 523 /* range filtering */ 524 if (x == MAX_12BIT) 525 x = 0; 526 527 if (likely(x && z1)) { 528 /* compute touch pressure resistance using equation #2 */ 529 Rt = z2; 530 Rt -= z1; 531 Rt *= x; 532 Rt *= ts->x_plate_ohms; 533 Rt /= z1; 534 Rt = (Rt + 2047) >> 12; 535 } else 536 Rt = 0; 537 538 if (ts->model == 7843) 539 Rt = ts->pressure_max / 2; 540 541 /* Sample found inconsistent by debouncing or pressure is beyond 542 * the maximum. Don't report it to user space, repeat at least 543 * once more the measurement 544 */ 545 if (ts->tc.ignore || Rt > ts->pressure_max) { 546 #ifdef VERBOSE 547 pr_debug("%s: ignored %d pressure %d\n", 548 ts->spi->dev.bus_id, ts->tc.ignore, Rt); 549 #endif 550 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 551 HRTIMER_MODE_REL); 552 return; 553 } 554 555 /* NOTE: We can't rely on the pressure to determine the pen down 556 * state, even this controller has a pressure sensor. The pressure 557 * value can fluctuate for quite a while after lifting the pen and 558 * in some cases may not even settle at the expected value. 559 * 560 * The only safe way to check for the pen up condition is in the 561 * timer by reading the pen signal state (it's a GPIO _and_ IRQ). 562 */ 563 if (Rt) { 564 struct input_dev *input = ts->input; 565 566 if (!ts->pendown) { 567 input_report_key(input, BTN_TOUCH, 1); 568 ts->pendown = 1; 569 #ifdef VERBOSE 570 dev_dbg(&ts->spi->dev, "DOWN\n"); 571 #endif 572 } 573 input_report_abs(input, ABS_X, x); 574 input_report_abs(input, ABS_Y, y); 575 input_report_abs(input, ABS_PRESSURE, Rt); 576 577 input_sync(input); 578 #ifdef VERBOSE 579 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); 580 #endif 581 } 582 583 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 584 HRTIMER_MODE_REL); 585 } 586 587 static int ads7846_debounce(void *ads, int data_idx, int *val) 588 { 589 struct ads7846 *ts = ads; 590 591 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { 592 /* Start over collecting consistent readings. */ 593 ts->read_rep = 0; 594 /* Repeat it, if this was the first read or the read 595 * wasn't consistent enough. */ 596 if (ts->read_cnt < ts->debounce_max) { 597 ts->last_read = *val; 598 ts->read_cnt++; 599 return ADS7846_FILTER_REPEAT; 600 } else { 601 /* Maximum number of debouncing reached and still 602 * not enough number of consistent readings. Abort 603 * the whole sample, repeat it in the next sampling 604 * period. 605 */ 606 ts->read_cnt = 0; 607 return ADS7846_FILTER_IGNORE; 608 } 609 } else { 610 if (++ts->read_rep > ts->debounce_rep) { 611 /* Got a good reading for this coordinate, 612 * go for the next one. */ 613 ts->read_cnt = 0; 614 ts->read_rep = 0; 615 return ADS7846_FILTER_OK; 616 } else { 617 /* Read more values that are consistent. */ 618 ts->read_cnt++; 619 return ADS7846_FILTER_REPEAT; 620 } 621 } 622 } 623 624 static int ads7846_no_filter(void *ads, int data_idx, int *val) 625 { 626 return ADS7846_FILTER_OK; 627 } 628 629 static void ads7846_rx_val(void *ads) 630 { 631 struct ads7846 *ts = ads; 632 struct spi_message *m; 633 struct spi_transfer *t; 634 u16 *rx_val; 635 int val; 636 int action; 637 int status; 638 639 m = &ts->msg[ts->msg_idx]; 640 t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 641 rx_val = t->rx_buf; 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_cpu(*rx_val) >> 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 *rx_val = 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 spi->dev.power.power_state = message; 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 spi->dev.power.power_state = PMSG_ON; 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_1; 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 spi->dev.power.power_state = PMSG_ON; 864 865 ts->spi = spi; 866 ts->input = input_dev; 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 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); 899 900 input_dev->name = "ADS784x Touchscreen"; 901 input_dev->phys = ts->phys; 902 input_dev->cdev.dev = &spi->dev; 903 904 input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS); 905 input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH); 906 input_set_abs_params(input_dev, ABS_X, 907 pdata->x_min ? : 0, 908 pdata->x_max ? : MAX_12BIT, 909 0, 0); 910 input_set_abs_params(input_dev, ABS_Y, 911 pdata->y_min ? : 0, 912 pdata->y_max ? : MAX_12BIT, 913 0, 0); 914 input_set_abs_params(input_dev, ABS_PRESSURE, 915 pdata->pressure_min, pdata->pressure_max, 0, 0); 916 917 vref = pdata->keep_vref_on; 918 919 /* set up the transfers to read touchscreen state; this assumes we 920 * use formula #2 for pressure, not #3. 921 */ 922 m = &ts->msg[0]; 923 x = ts->xfer; 924 925 spi_message_init(m); 926 927 /* y- still on; turn on only y+ (and ADC) */ 928 ts->read_y = READ_Y(vref); 929 x->tx_buf = &ts->read_y; 930 x->len = 1; 931 spi_message_add_tail(x, m); 932 933 x++; 934 x->rx_buf = &ts->tc.y; 935 x->len = 2; 936 spi_message_add_tail(x, m); 937 938 m->complete = ads7846_rx_val; 939 m->context = ts; 940 941 m++; 942 spi_message_init(m); 943 944 /* turn y- off, x+ on, then leave in lowpower */ 945 x++; 946 ts->read_x = READ_X(vref); 947 x->tx_buf = &ts->read_x; 948 x->len = 1; 949 spi_message_add_tail(x, m); 950 951 x++; 952 x->rx_buf = &ts->tc.x; 953 x->len = 2; 954 spi_message_add_tail(x, m); 955 956 m->complete = ads7846_rx_val; 957 m->context = ts; 958 959 /* turn y+ off, x- on; we'll use formula #2 */ 960 if (ts->model == 7846) { 961 m++; 962 spi_message_init(m); 963 964 x++; 965 ts->read_z1 = READ_Z1(vref); 966 x->tx_buf = &ts->read_z1; 967 x->len = 1; 968 spi_message_add_tail(x, m); 969 970 x++; 971 x->rx_buf = &ts->tc.z1; 972 x->len = 2; 973 spi_message_add_tail(x, m); 974 975 m->complete = ads7846_rx_val; 976 m->context = ts; 977 978 m++; 979 spi_message_init(m); 980 981 x++; 982 ts->read_z2 = READ_Z2(vref); 983 x->tx_buf = &ts->read_z2; 984 x->len = 1; 985 spi_message_add_tail(x, m); 986 987 x++; 988 x->rx_buf = &ts->tc.z2; 989 x->len = 2; 990 spi_message_add_tail(x, m); 991 992 m->complete = ads7846_rx_val; 993 m->context = ts; 994 } 995 996 /* power down */ 997 m++; 998 spi_message_init(m); 999 1000 x++; 1001 ts->pwrdown = PWRDOWN; 1002 x->tx_buf = &ts->pwrdown; 1003 x->len = 1; 1004 spi_message_add_tail(x, m); 1005 1006 x++; 1007 x->rx_buf = &ts->dummy; 1008 x->len = 2; 1009 CS_CHANGE(*x); 1010 spi_message_add_tail(x, m); 1011 1012 m->complete = ads7846_rx; 1013 m->context = ts; 1014 1015 ts->last_msg = m; 1016 1017 if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, 1018 spi->dev.driver->name, ts)) { 1019 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); 1020 err = -EBUSY; 1021 goto err_cleanup_filter; 1022 } 1023 1024 err = ads784x_hwmon_register(spi, ts); 1025 if (err) 1026 goto err_free_irq; 1027 1028 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); 1029 1030 /* take a first sample, leaving nPENIRQ active and vREF off; avoid 1031 * the touchscreen, in case it's not connected. 1032 */ 1033 (void) ads7846_read12_ser(&spi->dev, 1034 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); 1035 1036 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); 1037 if (err) 1038 goto err_remove_hwmon; 1039 1040 err = input_register_device(input_dev); 1041 if (err) 1042 goto err_remove_attr_group; 1043 1044 return 0; 1045 1046 err_remove_attr_group: 1047 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1048 err_remove_hwmon: 1049 ads784x_hwmon_unregister(spi, ts); 1050 err_free_irq: 1051 free_irq(spi->irq, ts); 1052 err_cleanup_filter: 1053 if (ts->filter_cleanup) 1054 ts->filter_cleanup(ts->filter_data); 1055 err_free_mem: 1056 input_free_device(input_dev); 1057 kfree(ts); 1058 return err; 1059 } 1060 1061 static int __devexit ads7846_remove(struct spi_device *spi) 1062 { 1063 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 1064 1065 ads784x_hwmon_unregister(spi, ts); 1066 input_unregister_device(ts->input); 1067 1068 ads7846_suspend(spi, PMSG_SUSPEND); 1069 1070 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1071 1072 free_irq(ts->spi->irq, ts); 1073 /* suspend left the IRQ disabled */ 1074 enable_irq(ts->spi->irq); 1075 1076 if (ts->filter_cleanup) 1077 ts->filter_cleanup(ts->filter_data); 1078 1079 kfree(ts); 1080 1081 dev_dbg(&spi->dev, "unregistered touchscreen\n"); 1082 return 0; 1083 } 1084 1085 static struct spi_driver ads7846_driver = { 1086 .driver = { 1087 .name = "ads7846", 1088 .bus = &spi_bus_type, 1089 .owner = THIS_MODULE, 1090 }, 1091 .probe = ads7846_probe, 1092 .remove = __devexit_p(ads7846_remove), 1093 .suspend = ads7846_suspend, 1094 .resume = ads7846_resume, 1095 }; 1096 1097 static int __init ads7846_init(void) 1098 { 1099 /* grr, board-specific init should stay out of drivers!! */ 1100 1101 #ifdef CONFIG_ARCH_OMAP 1102 if (machine_is_omap_osk()) { 1103 /* GPIO4 = PENIRQ; GPIO6 = BUSY */ 1104 omap_request_gpio(4); 1105 omap_set_gpio_direction(4, 1); 1106 omap_request_gpio(6); 1107 omap_set_gpio_direction(6, 1); 1108 } 1109 // also TI 1510 Innovator, bitbanging through FPGA 1110 // also Nokia 770 1111 // also Palm Tungsten T2 1112 #endif 1113 1114 // PXA: 1115 // also Dell Axim X50 1116 // also HP iPaq H191x/H192x/H415x/H435x 1117 // also Intel Lubbock (additional to UCB1400; as temperature sensor) 1118 // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky) 1119 1120 // Atmel at91sam9261-EK uses ads7843 1121 1122 // also various AMD Au1x00 devel boards 1123 1124 return spi_register_driver(&ads7846_driver); 1125 } 1126 module_init(ads7846_init); 1127 1128 static void __exit ads7846_exit(void) 1129 { 1130 spi_unregister_driver(&ads7846_driver); 1131 1132 #ifdef CONFIG_ARCH_OMAP 1133 if (machine_is_omap_osk()) { 1134 omap_free_gpio(4); 1135 omap_free_gpio(6); 1136 } 1137 #endif 1138 1139 } 1140 module_exit(ads7846_exit); 1141 1142 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); 1143 MODULE_LICENSE("GPL"); 1144