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 * TSC2046 is just newer ads7846 silicon. 43 * Support for ads7843 tested on Atmel at91sam926x-EK. 44 * Support for ads7845 has only been stubbed in. 45 * 46 * IRQ handling needs a workaround because of a shortcoming in handling 47 * edge triggered IRQs on some platforms like the OMAP1/2. These 48 * platforms don't handle the ARM lazy IRQ disabling properly, thus we 49 * have to maintain our own SW IRQ disabled status. This should be 50 * removed as soon as the affected platform's IRQ handling is fixed. 51 * 52 * app note sbaa036 talks in more detail about accurate sampling... 53 * that ought to help in situations like LCDs inducing noise (which 54 * can also be helped by using synch signals) and more generally. 55 * This driver tries to utilize the measures described in the app 56 * note. The strength of filtering can be set in the board-* specific 57 * files. 58 */ 59 60 #define TS_POLL_DELAY (1 * 1000000) /* ns delay before the first sample */ 61 #define TS_POLL_PERIOD (5 * 1000000) /* ns delay between samples */ 62 63 /* this driver doesn't aim at the peak continuous sample rate */ 64 #define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */) 65 66 struct ts_event { 67 /* For portability, we can't read 12 bit values using SPI (which 68 * would make the controller deliver them as native byteorder u16 69 * with msbs zeroed). Instead, we read them as two 8-bit values, 70 * *** WHICH NEED BYTESWAPPING *** and range adjustment. 71 */ 72 u16 x; 73 u16 y; 74 u16 z1, z2; 75 int ignore; 76 }; 77 78 struct ads7846 { 79 struct input_dev *input; 80 char phys[32]; 81 82 struct spi_device *spi; 83 84 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 85 struct attribute_group *attr_group; 86 struct class_device *hwmon; 87 #endif 88 89 u16 model; 90 u16 vref_delay_usecs; 91 u16 x_plate_ohms; 92 u16 pressure_max; 93 94 u8 read_x, read_y, read_z1, read_z2, pwrdown; 95 u16 dummy; /* for the pwrdown read */ 96 struct ts_event tc; 97 98 struct spi_transfer xfer[10]; 99 struct spi_message msg[5]; 100 struct spi_message *last_msg; 101 int msg_idx; 102 int read_cnt; 103 int read_rep; 104 int last_read; 105 106 u16 debounce_max; 107 u16 debounce_tol; 108 u16 debounce_rep; 109 110 spinlock_t lock; 111 struct hrtimer timer; 112 unsigned pendown:1; /* P: lock */ 113 unsigned pending:1; /* P: lock */ 114 // FIXME remove "irq_disabled" 115 unsigned irq_disabled:1; /* P: lock */ 116 unsigned disabled:1; 117 118 int (*filter)(void *data, int data_idx, int *val); 119 void *filter_data; 120 void (*filter_cleanup)(void *data); 121 int (*get_pendown_state)(void); 122 }; 123 124 /* leave chip selected when we're done, for quicker re-select? */ 125 #if 0 126 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) 127 #else 128 #define CS_CHANGE(xfer) ((xfer).cs_change = 0) 129 #endif 130 131 /*--------------------------------------------------------------------------*/ 132 133 /* The ADS7846 has touchscreen and other sensors. 134 * Earlier ads784x chips are somewhat compatible. 135 */ 136 #define ADS_START (1 << 7) 137 #define ADS_A2A1A0_d_y (1 << 4) /* differential */ 138 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ 139 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ 140 #define ADS_A2A1A0_d_x (5 << 4) /* differential */ 141 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ 142 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ 143 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ 144 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ 145 #define ADS_8_BIT (1 << 3) 146 #define ADS_12_BIT (0 << 3) 147 #define ADS_SER (1 << 2) /* non-differential */ 148 #define ADS_DFR (0 << 2) /* differential */ 149 #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ 150 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ 151 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ 152 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ 153 154 #define MAX_12BIT ((1<<12)-1) 155 156 /* leave ADC powered up (disables penirq) between differential samples */ 157 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ 158 | ADS_12_BIT | ADS_DFR | \ 159 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) 160 161 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) 162 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) 163 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) 164 165 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) 166 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ 167 168 /* single-ended samples need to first power up reference voltage; 169 * we leave both ADC and VREF powered 170 */ 171 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ 172 | ADS_12_BIT | ADS_SER) 173 174 #define REF_ON (READ_12BIT_DFR(x, 1, 1)) 175 #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) 176 177 /*--------------------------------------------------------------------------*/ 178 179 /* 180 * Non-touchscreen sensors only use single-ended conversions. 181 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; 182 * ads7846 lets that pin be unconnected, to use internal vREF. 183 */ 184 static unsigned vREF_mV; 185 module_param(vREF_mV, uint, 0); 186 MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts"); 187 188 struct ser_req { 189 u8 ref_on; 190 u8 command; 191 u8 ref_off; 192 u16 scratch; 193 __be16 sample; 194 struct spi_message msg; 195 struct spi_transfer xfer[6]; 196 }; 197 198 static void ads7846_enable(struct ads7846 *ts); 199 static void ads7846_disable(struct ads7846 *ts); 200 201 static int device_suspended(struct device *dev) 202 { 203 struct ads7846 *ts = dev_get_drvdata(dev); 204 return dev->power.power_state.event != PM_EVENT_ON || ts->disabled; 205 } 206 207 static int ads7846_read12_ser(struct device *dev, unsigned command) 208 { 209 struct spi_device *spi = to_spi_device(dev); 210 struct ads7846 *ts = dev_get_drvdata(dev); 211 struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); 212 int status; 213 int sample; 214 int use_internal; 215 216 if (!req) 217 return -ENOMEM; 218 219 spi_message_init(&req->msg); 220 221 /* FIXME boards with ads7846 might use external vref instead ... */ 222 use_internal = (ts->model == 7846); 223 224 /* maybe turn on internal vREF, and let it settle */ 225 if (use_internal) { 226 req->ref_on = REF_ON; 227 req->xfer[0].tx_buf = &req->ref_on; 228 req->xfer[0].len = 1; 229 spi_message_add_tail(&req->xfer[0], &req->msg); 230 231 req->xfer[1].rx_buf = &req->scratch; 232 req->xfer[1].len = 2; 233 234 /* for 1uF, settle for 800 usec; no cap, 100 usec. */ 235 req->xfer[1].delay_usecs = ts->vref_delay_usecs; 236 spi_message_add_tail(&req->xfer[1], &req->msg); 237 } 238 239 /* take sample */ 240 req->command = (u8) command; 241 req->xfer[2].tx_buf = &req->command; 242 req->xfer[2].len = 1; 243 spi_message_add_tail(&req->xfer[2], &req->msg); 244 245 req->xfer[3].rx_buf = &req->sample; 246 req->xfer[3].len = 2; 247 spi_message_add_tail(&req->xfer[3], &req->msg); 248 249 /* REVISIT: take a few more samples, and compare ... */ 250 251 /* converter in low power mode & enable PENIRQ */ 252 req->ref_off = PWRDOWN; 253 req->xfer[4].tx_buf = &req->ref_off; 254 req->xfer[4].len = 1; 255 spi_message_add_tail(&req->xfer[4], &req->msg); 256 257 req->xfer[5].rx_buf = &req->scratch; 258 req->xfer[5].len = 2; 259 CS_CHANGE(req->xfer[5]); 260 spi_message_add_tail(&req->xfer[5], &req->msg); 261 262 ts->irq_disabled = 1; 263 disable_irq(spi->irq); 264 status = spi_sync(spi, &req->msg); 265 ts->irq_disabled = 0; 266 enable_irq(spi->irq); 267 268 if (req->msg.status) 269 status = req->msg.status; 270 271 /* on-wire is a must-ignore bit, a BE12 value, then padding */ 272 sample = be16_to_cpu(req->sample); 273 sample = sample >> 3; 274 sample &= 0x0fff; 275 276 kfree(req); 277 return status ? status : sample; 278 } 279 280 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 281 282 #define SHOW(name, var, adjust) static ssize_t \ 283 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 284 { \ 285 struct ads7846 *ts = dev_get_drvdata(dev); \ 286 ssize_t v = ads7846_read12_ser(dev, \ 287 READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \ 288 if (v < 0) \ 289 return v; \ 290 return sprintf(buf, "%u\n", adjust(ts, v)); \ 291 } \ 292 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); 293 294 295 /* Sysfs conventions report temperatures in millidegrees Celcius. 296 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high 297 * accuracy scheme without calibration data. For now we won't try either; 298 * userspace sees raw sensor values, and must scale/calibrate appropriately. 299 */ 300 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) 301 { 302 return v; 303 } 304 305 SHOW(temp0, temp0, null_adjust) /* temp1_input */ 306 SHOW(temp1, temp1, null_adjust) /* temp2_input */ 307 308 309 /* sysfs conventions report voltages in millivolts. We can convert voltages 310 * if we know vREF. userspace may need to scale vAUX to match the board's 311 * external resistors; we assume that vBATT only uses the internal ones. 312 */ 313 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 314 { 315 unsigned retval = v; 316 317 /* external resistors may scale vAUX into 0..vREF */ 318 retval *= vREF_mV; 319 retval = retval >> 12; 320 return retval; 321 } 322 323 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) 324 { 325 unsigned retval = vaux_adjust(ts, v); 326 327 /* ads7846 has a resistor ladder to scale this signal down */ 328 if (ts->model == 7846) 329 retval *= 4; 330 return retval; 331 } 332 333 SHOW(in0_input, vaux, vaux_adjust) 334 SHOW(in1_input, vbatt, vbatt_adjust) 335 336 337 static struct attribute *ads7846_attributes[] = { 338 &dev_attr_temp0.attr, 339 &dev_attr_temp1.attr, 340 &dev_attr_in0_input.attr, 341 &dev_attr_in1_input.attr, 342 NULL, 343 }; 344 345 static struct attribute_group ads7846_attr_group = { 346 .attrs = ads7846_attributes, 347 }; 348 349 static struct attribute *ads7843_attributes[] = { 350 &dev_attr_in0_input.attr, 351 &dev_attr_in1_input.attr, 352 NULL, 353 }; 354 355 static struct attribute_group ads7843_attr_group = { 356 .attrs = ads7843_attributes, 357 }; 358 359 static struct attribute *ads7845_attributes[] = { 360 &dev_attr_in0_input.attr, 361 NULL, 362 }; 363 364 static struct attribute_group ads7845_attr_group = { 365 .attrs = ads7845_attributes, 366 }; 367 368 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 369 { 370 struct class_device *hwmon; 371 int err; 372 373 /* hwmon sensors need a reference voltage */ 374 switch (ts->model) { 375 case 7846: 376 if (!vREF_mV) { 377 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); 378 vREF_mV = 2500; 379 } 380 break; 381 case 7845: 382 case 7843: 383 if (!vREF_mV) { 384 dev_warn(&spi->dev, 385 "external vREF for ADS%d not specified\n", 386 ts->model); 387 return 0; 388 } 389 break; 390 } 391 392 /* different chips have different sensor groups */ 393 switch (ts->model) { 394 case 7846: 395 ts->attr_group = &ads7846_attr_group; 396 break; 397 case 7845: 398 ts->attr_group = &ads7845_attr_group; 399 break; 400 case 7843: 401 ts->attr_group = &ads7843_attr_group; 402 break; 403 default: 404 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); 405 return 0; 406 } 407 408 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); 409 if (err) 410 return err; 411 412 hwmon = hwmon_device_register(&spi->dev); 413 if (IS_ERR(hwmon)) { 414 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 415 return PTR_ERR(hwmon); 416 } 417 418 ts->hwmon = hwmon; 419 return 0; 420 } 421 422 static void ads784x_hwmon_unregister(struct spi_device *spi, 423 struct ads7846 *ts) 424 { 425 if (ts->hwmon) { 426 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 427 hwmon_device_unregister(ts->hwmon); 428 } 429 } 430 431 #else 432 static inline int ads784x_hwmon_register(struct spi_device *spi, 433 struct ads7846 *ts) 434 { 435 return 0; 436 } 437 438 static inline void ads784x_hwmon_unregister(struct spi_device *spi, 439 struct ads7846 *ts) 440 { 441 } 442 #endif 443 444 static int is_pen_down(struct device *dev) 445 { 446 struct ads7846 *ts = dev_get_drvdata(dev); 447 448 return ts->pendown; 449 } 450 451 static ssize_t ads7846_pen_down_show(struct device *dev, 452 struct device_attribute *attr, char *buf) 453 { 454 return sprintf(buf, "%u\n", is_pen_down(dev)); 455 } 456 457 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); 458 459 static ssize_t ads7846_disable_show(struct device *dev, 460 struct device_attribute *attr, char *buf) 461 { 462 struct ads7846 *ts = dev_get_drvdata(dev); 463 464 return sprintf(buf, "%u\n", ts->disabled); 465 } 466 467 static ssize_t ads7846_disable_store(struct device *dev, 468 struct device_attribute *attr, 469 const char *buf, size_t count) 470 { 471 struct ads7846 *ts = dev_get_drvdata(dev); 472 char *endp; 473 int i; 474 475 i = simple_strtoul(buf, &endp, 10); 476 spin_lock_irq(&ts->lock); 477 478 if (i) 479 ads7846_disable(ts); 480 else 481 ads7846_enable(ts); 482 483 spin_unlock_irq(&ts->lock); 484 485 return count; 486 } 487 488 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); 489 490 static struct attribute *ads784x_attributes[] = { 491 &dev_attr_pen_down.attr, 492 &dev_attr_disable.attr, 493 NULL, 494 }; 495 496 static struct attribute_group ads784x_attr_group = { 497 .attrs = ads784x_attributes, 498 }; 499 500 /*--------------------------------------------------------------------------*/ 501 502 /* 503 * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, 504 * to retrieve touchscreen status. 505 * 506 * The SPI transfer completion callback does the real work. It reports 507 * touchscreen events and reactivates the timer (or IRQ) as appropriate. 508 */ 509 510 static void ads7846_rx(void *ads) 511 { 512 struct ads7846 *ts = ads; 513 unsigned Rt; 514 u16 x, y, z1, z2; 515 516 /* ads7846_rx_val() did in-place conversion (including byteswap) from 517 * on-the-wire format as part of debouncing to get stable readings. 518 */ 519 x = ts->tc.x; 520 y = ts->tc.y; 521 z1 = ts->tc.z1; 522 z2 = ts->tc.z2; 523 524 /* range filtering */ 525 if (x == MAX_12BIT) 526 x = 0; 527 528 if (likely(x && z1)) { 529 /* compute touch pressure resistance using equation #2 */ 530 Rt = z2; 531 Rt -= z1; 532 Rt *= x; 533 Rt *= ts->x_plate_ohms; 534 Rt /= z1; 535 Rt = (Rt + 2047) >> 12; 536 } else 537 Rt = 0; 538 539 if (ts->model == 7843) 540 Rt = ts->pressure_max / 2; 541 542 /* Sample found inconsistent by debouncing or pressure is beyond 543 * the maximum. Don't report it to user space, repeat at least 544 * once more the measurement 545 */ 546 if (ts->tc.ignore || Rt > ts->pressure_max) { 547 #ifdef VERBOSE 548 pr_debug("%s: ignored %d pressure %d\n", 549 ts->spi->dev.bus_id, ts->tc.ignore, Rt); 550 #endif 551 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 552 HRTIMER_MODE_REL); 553 return; 554 } 555 556 /* NOTE: We can't rely on the pressure to determine the pen down 557 * state, even this controller has a pressure sensor. The pressure 558 * value can fluctuate for quite a while after lifting the pen and 559 * in some cases may not even settle at the expected value. 560 * 561 * The only safe way to check for the pen up condition is in the 562 * timer by reading the pen signal state (it's a GPIO _and_ IRQ). 563 */ 564 if (Rt) { 565 struct input_dev *input = ts->input; 566 567 if (!ts->pendown) { 568 input_report_key(input, BTN_TOUCH, 1); 569 ts->pendown = 1; 570 #ifdef VERBOSE 571 dev_dbg(&ts->spi->dev, "DOWN\n"); 572 #endif 573 } 574 input_report_abs(input, ABS_X, x); 575 input_report_abs(input, ABS_Y, y); 576 input_report_abs(input, ABS_PRESSURE, Rt); 577 578 input_sync(input); 579 #ifdef VERBOSE 580 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); 581 #endif 582 } 583 584 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 585 HRTIMER_MODE_REL); 586 } 587 588 static int ads7846_debounce(void *ads, int data_idx, int *val) 589 { 590 struct ads7846 *ts = ads; 591 592 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { 593 /* Start over collecting consistent readings. */ 594 ts->read_rep = 0; 595 /* Repeat it, if this was the first read or the read 596 * wasn't consistent enough. */ 597 if (ts->read_cnt < ts->debounce_max) { 598 ts->last_read = *val; 599 ts->read_cnt++; 600 return ADS7846_FILTER_REPEAT; 601 } else { 602 /* Maximum number of debouncing reached and still 603 * not enough number of consistent readings. Abort 604 * the whole sample, repeat it in the next sampling 605 * period. 606 */ 607 ts->read_cnt = 0; 608 return ADS7846_FILTER_IGNORE; 609 } 610 } else { 611 if (++ts->read_rep > ts->debounce_rep) { 612 /* Got a good reading for this coordinate, 613 * go for the next one. */ 614 ts->read_cnt = 0; 615 ts->read_rep = 0; 616 return ADS7846_FILTER_OK; 617 } else { 618 /* Read more values that are consistent. */ 619 ts->read_cnt++; 620 return ADS7846_FILTER_REPEAT; 621 } 622 } 623 } 624 625 static int ads7846_no_filter(void *ads, int data_idx, int *val) 626 { 627 return ADS7846_FILTER_OK; 628 } 629 630 static void ads7846_rx_val(void *ads) 631 { 632 struct ads7846 *ts = ads; 633 struct spi_message *m; 634 struct spi_transfer *t; 635 u16 *rx_val; 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 rx_val = t->rx_buf; 643 644 /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; 645 * built from two 8 bit values written msb-first. 646 */ 647 val = be16_to_cpu(*rx_val) >> 3; 648 649 action = ts->filter(ts->filter_data, ts->msg_idx, &val); 650 switch (action) { 651 case ADS7846_FILTER_REPEAT: 652 break; 653 case ADS7846_FILTER_IGNORE: 654 ts->tc.ignore = 1; 655 /* Last message will contain ads7846_rx() as the 656 * completion function. 657 */ 658 m = ts->last_msg; 659 break; 660 case ADS7846_FILTER_OK: 661 *rx_val = val; 662 ts->tc.ignore = 0; 663 m = &ts->msg[++ts->msg_idx]; 664 break; 665 default: 666 BUG(); 667 } 668 status = spi_async(ts->spi, m); 669 if (status) 670 dev_err(&ts->spi->dev, "spi_async --> %d\n", 671 status); 672 } 673 674 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle) 675 { 676 struct ads7846 *ts = container_of(handle, struct ads7846, timer); 677 int status = 0; 678 679 spin_lock_irq(&ts->lock); 680 681 if (unlikely(!ts->get_pendown_state() || 682 device_suspended(&ts->spi->dev))) { 683 if (ts->pendown) { 684 struct input_dev *input = ts->input; 685 686 input_report_key(input, BTN_TOUCH, 0); 687 input_report_abs(input, ABS_PRESSURE, 0); 688 input_sync(input); 689 690 ts->pendown = 0; 691 #ifdef VERBOSE 692 dev_dbg(&ts->spi->dev, "UP\n"); 693 #endif 694 } 695 696 /* measurement cycle ended */ 697 if (!device_suspended(&ts->spi->dev)) { 698 ts->irq_disabled = 0; 699 enable_irq(ts->spi->irq); 700 } 701 ts->pending = 0; 702 } else { 703 /* pen is still down, continue with the measurement */ 704 ts->msg_idx = 0; 705 status = spi_async(ts->spi, &ts->msg[0]); 706 if (status) 707 dev_err(&ts->spi->dev, "spi_async --> %d\n", status); 708 } 709 710 spin_unlock_irq(&ts->lock); 711 return HRTIMER_NORESTART; 712 } 713 714 static irqreturn_t ads7846_irq(int irq, void *handle) 715 { 716 struct ads7846 *ts = handle; 717 unsigned long flags; 718 719 spin_lock_irqsave(&ts->lock, flags); 720 if (likely(ts->get_pendown_state())) { 721 if (!ts->irq_disabled) { 722 /* The ARM do_simple_IRQ() dispatcher doesn't act 723 * like the other dispatchers: it will report IRQs 724 * even after they've been disabled. We work around 725 * that here. (The "generic irq" framework may help...) 726 */ 727 ts->irq_disabled = 1; 728 disable_irq(ts->spi->irq); 729 ts->pending = 1; 730 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY), 731 HRTIMER_MODE_REL); 732 } 733 } 734 spin_unlock_irqrestore(&ts->lock, flags); 735 736 return IRQ_HANDLED; 737 } 738 739 /*--------------------------------------------------------------------------*/ 740 741 /* Must be called with ts->lock held */ 742 static void ads7846_disable(struct ads7846 *ts) 743 { 744 if (ts->disabled) 745 return; 746 747 ts->disabled = 1; 748 749 /* are we waiting for IRQ, or polling? */ 750 if (!ts->pending) { 751 ts->irq_disabled = 1; 752 disable_irq(ts->spi->irq); 753 } else { 754 /* the timer will run at least once more, and 755 * leave everything in a clean state, IRQ disabled 756 */ 757 while (ts->pending) { 758 spin_unlock_irq(&ts->lock); 759 msleep(1); 760 spin_lock_irq(&ts->lock); 761 } 762 } 763 764 /* we know the chip's in lowpower mode since we always 765 * leave it that way after every request 766 */ 767 768 } 769 770 /* Must be called with ts->lock held */ 771 static void ads7846_enable(struct ads7846 *ts) 772 { 773 if (!ts->disabled) 774 return; 775 776 ts->disabled = 0; 777 ts->irq_disabled = 0; 778 enable_irq(ts->spi->irq); 779 } 780 781 static int ads7846_suspend(struct spi_device *spi, pm_message_t message) 782 { 783 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 784 785 spin_lock_irq(&ts->lock); 786 787 spi->dev.power.power_state = message; 788 ads7846_disable(ts); 789 790 spin_unlock_irq(&ts->lock); 791 792 return 0; 793 794 } 795 796 static int ads7846_resume(struct spi_device *spi) 797 { 798 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 799 800 spin_lock_irq(&ts->lock); 801 802 spi->dev.power.power_state = PMSG_ON; 803 ads7846_enable(ts); 804 805 spin_unlock_irq(&ts->lock); 806 807 return 0; 808 } 809 810 static int __devinit ads7846_probe(struct spi_device *spi) 811 { 812 struct ads7846 *ts; 813 struct input_dev *input_dev; 814 struct ads7846_platform_data *pdata = spi->dev.platform_data; 815 struct spi_message *m; 816 struct spi_transfer *x; 817 int vref; 818 int err; 819 820 if (!spi->irq) { 821 dev_dbg(&spi->dev, "no IRQ?\n"); 822 return -ENODEV; 823 } 824 825 if (!pdata) { 826 dev_dbg(&spi->dev, "no platform data?\n"); 827 return -ENODEV; 828 } 829 830 /* don't exceed max specified sample rate */ 831 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { 832 dev_dbg(&spi->dev, "f(sample) %d KHz?\n", 833 (spi->max_speed_hz/SAMPLE_BITS)/1000); 834 return -EINVAL; 835 } 836 837 /* REVISIT when the irq can be triggered active-low, or if for some 838 * reason the touchscreen isn't hooked up, we don't need to access 839 * the pendown state. 840 */ 841 if (pdata->get_pendown_state == NULL) { 842 dev_dbg(&spi->dev, "no get_pendown_state function?\n"); 843 return -EINVAL; 844 } 845 846 /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except 847 * that even if the hardware can do that, the SPI controller driver 848 * may not. So we stick to very-portable 8 bit words, both RX and TX. 849 */ 850 spi->bits_per_word = 8; 851 spi->mode = SPI_MODE_0; 852 err = spi_setup(spi); 853 if (err < 0) 854 return err; 855 856 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); 857 input_dev = input_allocate_device(); 858 if (!ts || !input_dev) { 859 err = -ENOMEM; 860 goto err_free_mem; 861 } 862 863 dev_set_drvdata(&spi->dev, ts); 864 spi->dev.power.power_state = PMSG_ON; 865 866 ts->spi = spi; 867 ts->input = input_dev; 868 869 hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 870 ts->timer.function = ads7846_timer; 871 872 spin_lock_init(&ts->lock); 873 874 ts->model = pdata->model ? : 7846; 875 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; 876 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; 877 ts->pressure_max = pdata->pressure_max ? : ~0; 878 879 if (pdata->filter != NULL) { 880 if (pdata->filter_init != NULL) { 881 err = pdata->filter_init(pdata, &ts->filter_data); 882 if (err < 0) 883 goto err_free_mem; 884 } 885 ts->filter = pdata->filter; 886 ts->filter_cleanup = pdata->filter_cleanup; 887 } else if (pdata->debounce_max) { 888 ts->debounce_max = pdata->debounce_max; 889 if (ts->debounce_max < 2) 890 ts->debounce_max = 2; 891 ts->debounce_tol = pdata->debounce_tol; 892 ts->debounce_rep = pdata->debounce_rep; 893 ts->filter = ads7846_debounce; 894 ts->filter_data = ts; 895 } else 896 ts->filter = ads7846_no_filter; 897 ts->get_pendown_state = pdata->get_pendown_state; 898 899 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); 900 901 input_dev->name = "ADS784x Touchscreen"; 902 input_dev->phys = ts->phys; 903 input_dev->dev.parent = &spi->dev; 904 905 input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS); 906 input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH); 907 input_set_abs_params(input_dev, ABS_X, 908 pdata->x_min ? : 0, 909 pdata->x_max ? : MAX_12BIT, 910 0, 0); 911 input_set_abs_params(input_dev, ABS_Y, 912 pdata->y_min ? : 0, 913 pdata->y_max ? : MAX_12BIT, 914 0, 0); 915 input_set_abs_params(input_dev, ABS_PRESSURE, 916 pdata->pressure_min, pdata->pressure_max, 0, 0); 917 918 vref = pdata->keep_vref_on; 919 920 /* set up the transfers to read touchscreen state; this assumes we 921 * use formula #2 for pressure, not #3. 922 */ 923 m = &ts->msg[0]; 924 x = ts->xfer; 925 926 spi_message_init(m); 927 928 /* y- still on; turn on only y+ (and ADC) */ 929 ts->read_y = READ_Y(vref); 930 x->tx_buf = &ts->read_y; 931 x->len = 1; 932 spi_message_add_tail(x, m); 933 934 x++; 935 x->rx_buf = &ts->tc.y; 936 x->len = 2; 937 spi_message_add_tail(x, m); 938 939 m->complete = ads7846_rx_val; 940 m->context = ts; 941 942 m++; 943 spi_message_init(m); 944 945 /* turn y- off, x+ on, then leave in lowpower */ 946 x++; 947 ts->read_x = READ_X(vref); 948 x->tx_buf = &ts->read_x; 949 x->len = 1; 950 spi_message_add_tail(x, m); 951 952 x++; 953 x->rx_buf = &ts->tc.x; 954 x->len = 2; 955 spi_message_add_tail(x, m); 956 957 m->complete = ads7846_rx_val; 958 m->context = ts; 959 960 /* turn y+ off, x- on; we'll use formula #2 */ 961 if (ts->model == 7846) { 962 m++; 963 spi_message_init(m); 964 965 x++; 966 ts->read_z1 = READ_Z1(vref); 967 x->tx_buf = &ts->read_z1; 968 x->len = 1; 969 spi_message_add_tail(x, m); 970 971 x++; 972 x->rx_buf = &ts->tc.z1; 973 x->len = 2; 974 spi_message_add_tail(x, m); 975 976 m->complete = ads7846_rx_val; 977 m->context = ts; 978 979 m++; 980 spi_message_init(m); 981 982 x++; 983 ts->read_z2 = READ_Z2(vref); 984 x->tx_buf = &ts->read_z2; 985 x->len = 1; 986 spi_message_add_tail(x, m); 987 988 x++; 989 x->rx_buf = &ts->tc.z2; 990 x->len = 2; 991 spi_message_add_tail(x, m); 992 993 m->complete = ads7846_rx_val; 994 m->context = ts; 995 } 996 997 /* power down */ 998 m++; 999 spi_message_init(m); 1000 1001 x++; 1002 ts->pwrdown = PWRDOWN; 1003 x->tx_buf = &ts->pwrdown; 1004 x->len = 1; 1005 spi_message_add_tail(x, m); 1006 1007 x++; 1008 x->rx_buf = &ts->dummy; 1009 x->len = 2; 1010 CS_CHANGE(*x); 1011 spi_message_add_tail(x, m); 1012 1013 m->complete = ads7846_rx; 1014 m->context = ts; 1015 1016 ts->last_msg = m; 1017 1018 if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, 1019 spi->dev.driver->name, ts)) { 1020 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); 1021 err = -EBUSY; 1022 goto err_cleanup_filter; 1023 } 1024 1025 err = ads784x_hwmon_register(spi, ts); 1026 if (err) 1027 goto err_free_irq; 1028 1029 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); 1030 1031 /* take a first sample, leaving nPENIRQ active and vREF off; avoid 1032 * the touchscreen, in case it's not connected. 1033 */ 1034 (void) ads7846_read12_ser(&spi->dev, 1035 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); 1036 1037 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); 1038 if (err) 1039 goto err_remove_hwmon; 1040 1041 err = input_register_device(input_dev); 1042 if (err) 1043 goto err_remove_attr_group; 1044 1045 return 0; 1046 1047 err_remove_attr_group: 1048 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1049 err_remove_hwmon: 1050 ads784x_hwmon_unregister(spi, ts); 1051 err_free_irq: 1052 free_irq(spi->irq, ts); 1053 err_cleanup_filter: 1054 if (ts->filter_cleanup) 1055 ts->filter_cleanup(ts->filter_data); 1056 err_free_mem: 1057 input_free_device(input_dev); 1058 kfree(ts); 1059 return err; 1060 } 1061 1062 static int __devexit ads7846_remove(struct spi_device *spi) 1063 { 1064 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 1065 1066 ads784x_hwmon_unregister(spi, ts); 1067 input_unregister_device(ts->input); 1068 1069 ads7846_suspend(spi, PMSG_SUSPEND); 1070 1071 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1072 1073 free_irq(ts->spi->irq, ts); 1074 /* suspend left the IRQ disabled */ 1075 enable_irq(ts->spi->irq); 1076 1077 if (ts->filter_cleanup) 1078 ts->filter_cleanup(ts->filter_data); 1079 1080 kfree(ts); 1081 1082 dev_dbg(&spi->dev, "unregistered touchscreen\n"); 1083 return 0; 1084 } 1085 1086 static struct spi_driver ads7846_driver = { 1087 .driver = { 1088 .name = "ads7846", 1089 .bus = &spi_bus_type, 1090 .owner = THIS_MODULE, 1091 }, 1092 .probe = ads7846_probe, 1093 .remove = __devexit_p(ads7846_remove), 1094 .suspend = ads7846_suspend, 1095 .resume = ads7846_resume, 1096 }; 1097 1098 static int __init ads7846_init(void) 1099 { 1100 /* grr, board-specific init should stay out of drivers!! */ 1101 1102 #ifdef CONFIG_ARCH_OMAP 1103 if (machine_is_omap_osk()) { 1104 /* GPIO4 = PENIRQ; GPIO6 = BUSY */ 1105 omap_request_gpio(4); 1106 omap_set_gpio_direction(4, 1); 1107 omap_request_gpio(6); 1108 omap_set_gpio_direction(6, 1); 1109 } 1110 // also TI 1510 Innovator, bitbanging through FPGA 1111 // also Nokia 770 1112 // also Palm Tungsten T2 1113 #endif 1114 1115 // PXA: 1116 // also Dell Axim X50 1117 // also HP iPaq H191x/H192x/H415x/H435x 1118 // also Intel Lubbock (additional to UCB1400; as temperature sensor) 1119 // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky) 1120 1121 // Atmel at91sam9261-EK uses ads7843 1122 1123 // also various AMD Au1x00 devel boards 1124 1125 return spi_register_driver(&ads7846_driver); 1126 } 1127 module_init(ads7846_init); 1128 1129 static void __exit ads7846_exit(void) 1130 { 1131 spi_unregister_driver(&ads7846_driver); 1132 1133 #ifdef CONFIG_ARCH_OMAP 1134 if (machine_is_omap_osk()) { 1135 omap_free_gpio(4); 1136 omap_free_gpio(6); 1137 } 1138 #endif 1139 1140 } 1141 module_exit(ads7846_exit); 1142 1143 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); 1144 MODULE_LICENSE("GPL"); 1145