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 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[18]; 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 u16 penirq_recheck_delay_usecs; 111 112 spinlock_t lock; 113 struct hrtimer timer; 114 unsigned pendown:1; /* P: lock */ 115 unsigned pending:1; /* P: lock */ 116 // FIXME remove "irq_disabled" 117 unsigned irq_disabled:1; /* P: lock */ 118 unsigned disabled:1; 119 unsigned is_suspended:1; 120 121 int (*filter)(void *data, int data_idx, int *val); 122 void *filter_data; 123 void (*filter_cleanup)(void *data); 124 int (*get_pendown_state)(void); 125 }; 126 127 /* leave chip selected when we're done, for quicker re-select? */ 128 #if 0 129 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) 130 #else 131 #define CS_CHANGE(xfer) ((xfer).cs_change = 0) 132 #endif 133 134 /*--------------------------------------------------------------------------*/ 135 136 /* The ADS7846 has touchscreen and other sensors. 137 * Earlier ads784x chips are somewhat compatible. 138 */ 139 #define ADS_START (1 << 7) 140 #define ADS_A2A1A0_d_y (1 << 4) /* differential */ 141 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ 142 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ 143 #define ADS_A2A1A0_d_x (5 << 4) /* differential */ 144 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ 145 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ 146 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ 147 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ 148 #define ADS_8_BIT (1 << 3) 149 #define ADS_12_BIT (0 << 3) 150 #define ADS_SER (1 << 2) /* non-differential */ 151 #define ADS_DFR (0 << 2) /* differential */ 152 #define ADS_PD10_PDOWN (0 << 0) /* lowpower mode + penirq */ 153 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ 154 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ 155 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ 156 157 #define MAX_12BIT ((1<<12)-1) 158 159 /* leave ADC powered up (disables penirq) between differential samples */ 160 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ 161 | ADS_12_BIT | ADS_DFR | \ 162 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) 163 164 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) 165 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) 166 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) 167 168 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) 169 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ 170 171 /* single-ended samples need to first power up reference voltage; 172 * we leave both ADC and VREF powered 173 */ 174 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ 175 | ADS_12_BIT | ADS_SER) 176 177 #define REF_ON (READ_12BIT_DFR(x, 1, 1)) 178 #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) 179 180 /*--------------------------------------------------------------------------*/ 181 182 /* 183 * Non-touchscreen sensors only use single-ended conversions. 184 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; 185 * ads7846 lets that pin be unconnected, to use internal vREF. 186 */ 187 static unsigned vREF_mV; 188 module_param(vREF_mV, uint, 0); 189 MODULE_PARM_DESC(vREF_mV, "external vREF voltage, in milliVolts"); 190 191 struct ser_req { 192 u8 ref_on; 193 u8 command; 194 u8 ref_off; 195 u16 scratch; 196 __be16 sample; 197 struct spi_message msg; 198 struct spi_transfer xfer[6]; 199 }; 200 201 static void ads7846_enable(struct ads7846 *ts); 202 static void ads7846_disable(struct ads7846 *ts); 203 204 static int device_suspended(struct device *dev) 205 { 206 struct ads7846 *ts = dev_get_drvdata(dev); 207 return ts->is_suspended || ts->disabled; 208 } 209 210 static int ads7846_read12_ser(struct device *dev, unsigned command) 211 { 212 struct spi_device *spi = to_spi_device(dev); 213 struct ads7846 *ts = dev_get_drvdata(dev); 214 struct ser_req *req = kzalloc(sizeof *req, GFP_KERNEL); 215 int status; 216 int uninitialized_var(sample); 217 int use_internal; 218 219 if (!req) 220 return -ENOMEM; 221 222 spi_message_init(&req->msg); 223 224 /* FIXME boards with ads7846 might use external vref instead ... */ 225 use_internal = (ts->model == 7846); 226 227 /* maybe turn on internal vREF, and let it settle */ 228 if (use_internal) { 229 req->ref_on = REF_ON; 230 req->xfer[0].tx_buf = &req->ref_on; 231 req->xfer[0].len = 1; 232 spi_message_add_tail(&req->xfer[0], &req->msg); 233 234 req->xfer[1].rx_buf = &req->scratch; 235 req->xfer[1].len = 2; 236 237 /* for 1uF, settle for 800 usec; no cap, 100 usec. */ 238 req->xfer[1].delay_usecs = ts->vref_delay_usecs; 239 spi_message_add_tail(&req->xfer[1], &req->msg); 240 } 241 242 /* take sample */ 243 req->command = (u8) command; 244 req->xfer[2].tx_buf = &req->command; 245 req->xfer[2].len = 1; 246 spi_message_add_tail(&req->xfer[2], &req->msg); 247 248 req->xfer[3].rx_buf = &req->sample; 249 req->xfer[3].len = 2; 250 spi_message_add_tail(&req->xfer[3], &req->msg); 251 252 /* REVISIT: take a few more samples, and compare ... */ 253 254 /* converter in low power mode & enable PENIRQ */ 255 req->ref_off = PWRDOWN; 256 req->xfer[4].tx_buf = &req->ref_off; 257 req->xfer[4].len = 1; 258 spi_message_add_tail(&req->xfer[4], &req->msg); 259 260 req->xfer[5].rx_buf = &req->scratch; 261 req->xfer[5].len = 2; 262 CS_CHANGE(req->xfer[5]); 263 spi_message_add_tail(&req->xfer[5], &req->msg); 264 265 ts->irq_disabled = 1; 266 disable_irq(spi->irq); 267 status = spi_sync(spi, &req->msg); 268 ts->irq_disabled = 0; 269 enable_irq(spi->irq); 270 271 if (status == 0) { 272 /* on-wire is a must-ignore bit, a BE12 value, then padding */ 273 sample = be16_to_cpu(req->sample); 274 sample = sample >> 3; 275 sample &= 0x0fff; 276 } 277 278 kfree(req); 279 return status ? status : sample; 280 } 281 282 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 283 284 #define SHOW(name, var, adjust) static ssize_t \ 285 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 286 { \ 287 struct ads7846 *ts = dev_get_drvdata(dev); \ 288 ssize_t v = ads7846_read12_ser(dev, \ 289 READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \ 290 if (v < 0) \ 291 return v; \ 292 return sprintf(buf, "%u\n", adjust(ts, v)); \ 293 } \ 294 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); 295 296 297 /* Sysfs conventions report temperatures in millidegrees Celcius. 298 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high 299 * accuracy scheme without calibration data. For now we won't try either; 300 * userspace sees raw sensor values, and must scale/calibrate appropriately. 301 */ 302 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) 303 { 304 return v; 305 } 306 307 SHOW(temp0, temp0, null_adjust) /* temp1_input */ 308 SHOW(temp1, temp1, null_adjust) /* temp2_input */ 309 310 311 /* sysfs conventions report voltages in millivolts. We can convert voltages 312 * if we know vREF. userspace may need to scale vAUX to match the board's 313 * external resistors; we assume that vBATT only uses the internal ones. 314 */ 315 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 316 { 317 unsigned retval = v; 318 319 /* external resistors may scale vAUX into 0..vREF */ 320 retval *= vREF_mV; 321 retval = retval >> 12; 322 return retval; 323 } 324 325 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) 326 { 327 unsigned retval = vaux_adjust(ts, v); 328 329 /* ads7846 has a resistor ladder to scale this signal down */ 330 if (ts->model == 7846) 331 retval *= 4; 332 return retval; 333 } 334 335 SHOW(in0_input, vaux, vaux_adjust) 336 SHOW(in1_input, vbatt, vbatt_adjust) 337 338 339 static struct attribute *ads7846_attributes[] = { 340 &dev_attr_temp0.attr, 341 &dev_attr_temp1.attr, 342 &dev_attr_in0_input.attr, 343 &dev_attr_in1_input.attr, 344 NULL, 345 }; 346 347 static struct attribute_group ads7846_attr_group = { 348 .attrs = ads7846_attributes, 349 }; 350 351 static struct attribute *ads7843_attributes[] = { 352 &dev_attr_in0_input.attr, 353 &dev_attr_in1_input.attr, 354 NULL, 355 }; 356 357 static struct attribute_group ads7843_attr_group = { 358 .attrs = ads7843_attributes, 359 }; 360 361 static struct attribute *ads7845_attributes[] = { 362 &dev_attr_in0_input.attr, 363 NULL, 364 }; 365 366 static struct attribute_group ads7845_attr_group = { 367 .attrs = ads7845_attributes, 368 }; 369 370 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 371 { 372 struct device *hwmon; 373 int err; 374 375 /* hwmon sensors need a reference voltage */ 376 switch (ts->model) { 377 case 7846: 378 if (!vREF_mV) { 379 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); 380 vREF_mV = 2500; 381 } 382 break; 383 case 7845: 384 case 7843: 385 if (!vREF_mV) { 386 dev_warn(&spi->dev, 387 "external vREF for ADS%d not specified\n", 388 ts->model); 389 return 0; 390 } 391 break; 392 } 393 394 /* different chips have different sensor groups */ 395 switch (ts->model) { 396 case 7846: 397 ts->attr_group = &ads7846_attr_group; 398 break; 399 case 7845: 400 ts->attr_group = &ads7845_attr_group; 401 break; 402 case 7843: 403 ts->attr_group = &ads7843_attr_group; 404 break; 405 default: 406 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); 407 return 0; 408 } 409 410 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); 411 if (err) 412 return err; 413 414 hwmon = hwmon_device_register(&spi->dev); 415 if (IS_ERR(hwmon)) { 416 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 417 return PTR_ERR(hwmon); 418 } 419 420 ts->hwmon = hwmon; 421 return 0; 422 } 423 424 static void ads784x_hwmon_unregister(struct spi_device *spi, 425 struct ads7846 *ts) 426 { 427 if (ts->hwmon) { 428 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 429 hwmon_device_unregister(ts->hwmon); 430 } 431 } 432 433 #else 434 static inline int ads784x_hwmon_register(struct spi_device *spi, 435 struct ads7846 *ts) 436 { 437 return 0; 438 } 439 440 static inline void ads784x_hwmon_unregister(struct spi_device *spi, 441 struct ads7846 *ts) 442 { 443 } 444 #endif 445 446 static int is_pen_down(struct device *dev) 447 { 448 struct ads7846 *ts = dev_get_drvdata(dev); 449 450 return ts->pendown; 451 } 452 453 static ssize_t ads7846_pen_down_show(struct device *dev, 454 struct device_attribute *attr, char *buf) 455 { 456 return sprintf(buf, "%u\n", is_pen_down(dev)); 457 } 458 459 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); 460 461 static ssize_t ads7846_disable_show(struct device *dev, 462 struct device_attribute *attr, char *buf) 463 { 464 struct ads7846 *ts = dev_get_drvdata(dev); 465 466 return sprintf(buf, "%u\n", ts->disabled); 467 } 468 469 static ssize_t ads7846_disable_store(struct device *dev, 470 struct device_attribute *attr, 471 const char *buf, size_t count) 472 { 473 struct ads7846 *ts = dev_get_drvdata(dev); 474 char *endp; 475 int i; 476 477 i = simple_strtoul(buf, &endp, 10); 478 spin_lock_irq(&ts->lock); 479 480 if (i) 481 ads7846_disable(ts); 482 else 483 ads7846_enable(ts); 484 485 spin_unlock_irq(&ts->lock); 486 487 return count; 488 } 489 490 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); 491 492 static struct attribute *ads784x_attributes[] = { 493 &dev_attr_pen_down.attr, 494 &dev_attr_disable.attr, 495 NULL, 496 }; 497 498 static struct attribute_group ads784x_attr_group = { 499 .attrs = ads784x_attributes, 500 }; 501 502 /*--------------------------------------------------------------------------*/ 503 504 /* 505 * PENIRQ only kicks the timer. The timer only reissues the SPI transfer, 506 * to retrieve touchscreen status. 507 * 508 * The SPI transfer completion callback does the real work. It reports 509 * touchscreen events and reactivates the timer (or IRQ) as appropriate. 510 */ 511 512 static void ads7846_rx(void *ads) 513 { 514 struct ads7846 *ts = ads; 515 unsigned Rt; 516 u16 x, y, z1, z2; 517 518 /* ads7846_rx_val() did in-place conversion (including byteswap) from 519 * on-the-wire format as part of debouncing to get stable readings. 520 */ 521 x = ts->tc.x; 522 y = ts->tc.y; 523 z1 = ts->tc.z1; 524 z2 = ts->tc.z2; 525 526 /* range filtering */ 527 if (x == MAX_12BIT) 528 x = 0; 529 530 if (likely(x && z1)) { 531 /* compute touch pressure resistance using equation #2 */ 532 Rt = z2; 533 Rt -= z1; 534 Rt *= x; 535 Rt *= ts->x_plate_ohms; 536 Rt /= z1; 537 Rt = (Rt + 2047) >> 12; 538 } else 539 Rt = 0; 540 541 if (ts->model == 7843) 542 Rt = ts->pressure_max / 2; 543 544 /* Sample found inconsistent by debouncing or pressure is beyond 545 * the maximum. Don't report it to user space, repeat at least 546 * once more the measurement 547 */ 548 if (ts->tc.ignore || Rt > ts->pressure_max) { 549 #ifdef VERBOSE 550 pr_debug("%s: ignored %d pressure %d\n", 551 ts->spi->dev.bus_id, ts->tc.ignore, Rt); 552 #endif 553 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 554 HRTIMER_MODE_REL); 555 return; 556 } 557 558 /* Maybe check the pendown state before reporting. This discards 559 * false readings when the pen is lifted. 560 */ 561 if (ts->penirq_recheck_delay_usecs) { 562 udelay(ts->penirq_recheck_delay_usecs); 563 if (!ts->get_pendown_state()) 564 Rt = 0; 565 } 566 567 /* NOTE: We can't rely on the pressure to determine the pen down 568 * state, even this controller has a pressure sensor. The pressure 569 * value can fluctuate for quite a while after lifting the pen and 570 * in some cases may not even settle at the expected value. 571 * 572 * The only safe way to check for the pen up condition is in the 573 * timer by reading the pen signal state (it's a GPIO _and_ IRQ). 574 */ 575 if (Rt) { 576 struct input_dev *input = ts->input; 577 578 if (!ts->pendown) { 579 input_report_key(input, BTN_TOUCH, 1); 580 ts->pendown = 1; 581 #ifdef VERBOSE 582 dev_dbg(&ts->spi->dev, "DOWN\n"); 583 #endif 584 } 585 input_report_abs(input, ABS_X, x); 586 input_report_abs(input, ABS_Y, y); 587 input_report_abs(input, ABS_PRESSURE, Rt); 588 589 input_sync(input); 590 #ifdef VERBOSE 591 dev_dbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); 592 #endif 593 } 594 595 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), 596 HRTIMER_MODE_REL); 597 } 598 599 static int ads7846_debounce(void *ads, int data_idx, int *val) 600 { 601 struct ads7846 *ts = ads; 602 603 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { 604 /* Start over collecting consistent readings. */ 605 ts->read_rep = 0; 606 /* Repeat it, if this was the first read or the read 607 * wasn't consistent enough. */ 608 if (ts->read_cnt < ts->debounce_max) { 609 ts->last_read = *val; 610 ts->read_cnt++; 611 return ADS7846_FILTER_REPEAT; 612 } else { 613 /* Maximum number of debouncing reached and still 614 * not enough number of consistent readings. Abort 615 * the whole sample, repeat it in the next sampling 616 * period. 617 */ 618 ts->read_cnt = 0; 619 return ADS7846_FILTER_IGNORE; 620 } 621 } else { 622 if (++ts->read_rep > ts->debounce_rep) { 623 /* Got a good reading for this coordinate, 624 * go for the next one. */ 625 ts->read_cnt = 0; 626 ts->read_rep = 0; 627 return ADS7846_FILTER_OK; 628 } else { 629 /* Read more values that are consistent. */ 630 ts->read_cnt++; 631 return ADS7846_FILTER_REPEAT; 632 } 633 } 634 } 635 636 static int ads7846_no_filter(void *ads, int data_idx, int *val) 637 { 638 return ADS7846_FILTER_OK; 639 } 640 641 static void ads7846_rx_val(void *ads) 642 { 643 struct ads7846 *ts = ads; 644 struct spi_message *m; 645 struct spi_transfer *t; 646 u16 *rx_val; 647 int val; 648 int action; 649 int status; 650 651 m = &ts->msg[ts->msg_idx]; 652 t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 653 rx_val = t->rx_buf; 654 655 /* adjust: on-wire is a must-ignore bit, a BE12 value, then padding; 656 * built from two 8 bit values written msb-first. 657 */ 658 val = be16_to_cpu(*rx_val) >> 3; 659 660 action = ts->filter(ts->filter_data, ts->msg_idx, &val); 661 switch (action) { 662 case ADS7846_FILTER_REPEAT: 663 break; 664 case ADS7846_FILTER_IGNORE: 665 ts->tc.ignore = 1; 666 /* Last message will contain ads7846_rx() as the 667 * completion function. 668 */ 669 m = ts->last_msg; 670 break; 671 case ADS7846_FILTER_OK: 672 *rx_val = val; 673 ts->tc.ignore = 0; 674 m = &ts->msg[++ts->msg_idx]; 675 break; 676 default: 677 BUG(); 678 } 679 status = spi_async(ts->spi, m); 680 if (status) 681 dev_err(&ts->spi->dev, "spi_async --> %d\n", 682 status); 683 } 684 685 static enum hrtimer_restart ads7846_timer(struct hrtimer *handle) 686 { 687 struct ads7846 *ts = container_of(handle, struct ads7846, timer); 688 int status = 0; 689 690 spin_lock_irq(&ts->lock); 691 692 if (unlikely(!ts->get_pendown_state() || 693 device_suspended(&ts->spi->dev))) { 694 if (ts->pendown) { 695 struct input_dev *input = ts->input; 696 697 input_report_key(input, BTN_TOUCH, 0); 698 input_report_abs(input, ABS_PRESSURE, 0); 699 input_sync(input); 700 701 ts->pendown = 0; 702 #ifdef VERBOSE 703 dev_dbg(&ts->spi->dev, "UP\n"); 704 #endif 705 } 706 707 /* measurement cycle ended */ 708 if (!device_suspended(&ts->spi->dev)) { 709 ts->irq_disabled = 0; 710 enable_irq(ts->spi->irq); 711 } 712 ts->pending = 0; 713 } else { 714 /* pen is still down, continue with the measurement */ 715 ts->msg_idx = 0; 716 status = spi_async(ts->spi, &ts->msg[0]); 717 if (status) 718 dev_err(&ts->spi->dev, "spi_async --> %d\n", status); 719 } 720 721 spin_unlock_irq(&ts->lock); 722 return HRTIMER_NORESTART; 723 } 724 725 static irqreturn_t ads7846_irq(int irq, void *handle) 726 { 727 struct ads7846 *ts = handle; 728 unsigned long flags; 729 730 spin_lock_irqsave(&ts->lock, flags); 731 if (likely(ts->get_pendown_state())) { 732 if (!ts->irq_disabled) { 733 /* The ARM do_simple_IRQ() dispatcher doesn't act 734 * like the other dispatchers: it will report IRQs 735 * even after they've been disabled. We work around 736 * that here. (The "generic irq" framework may help...) 737 */ 738 ts->irq_disabled = 1; 739 disable_irq(ts->spi->irq); 740 ts->pending = 1; 741 hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY), 742 HRTIMER_MODE_REL); 743 } 744 } 745 spin_unlock_irqrestore(&ts->lock, flags); 746 747 return IRQ_HANDLED; 748 } 749 750 /*--------------------------------------------------------------------------*/ 751 752 /* Must be called with ts->lock held */ 753 static void ads7846_disable(struct ads7846 *ts) 754 { 755 if (ts->disabled) 756 return; 757 758 ts->disabled = 1; 759 760 /* are we waiting for IRQ, or polling? */ 761 if (!ts->pending) { 762 ts->irq_disabled = 1; 763 disable_irq(ts->spi->irq); 764 } else { 765 /* the timer will run at least once more, and 766 * leave everything in a clean state, IRQ disabled 767 */ 768 while (ts->pending) { 769 spin_unlock_irq(&ts->lock); 770 msleep(1); 771 spin_lock_irq(&ts->lock); 772 } 773 } 774 775 /* we know the chip's in lowpower mode since we always 776 * leave it that way after every request 777 */ 778 779 } 780 781 /* Must be called with ts->lock held */ 782 static void ads7846_enable(struct ads7846 *ts) 783 { 784 if (!ts->disabled) 785 return; 786 787 ts->disabled = 0; 788 ts->irq_disabled = 0; 789 enable_irq(ts->spi->irq); 790 } 791 792 static int ads7846_suspend(struct spi_device *spi, pm_message_t message) 793 { 794 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 795 796 spin_lock_irq(&ts->lock); 797 798 ts->is_suspended = 1; 799 ads7846_disable(ts); 800 801 spin_unlock_irq(&ts->lock); 802 803 return 0; 804 805 } 806 807 static int ads7846_resume(struct spi_device *spi) 808 { 809 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 810 811 spin_lock_irq(&ts->lock); 812 813 ts->is_suspended = 0; 814 ads7846_enable(ts); 815 816 spin_unlock_irq(&ts->lock); 817 818 return 0; 819 } 820 821 static int __devinit ads7846_probe(struct spi_device *spi) 822 { 823 struct ads7846 *ts; 824 struct input_dev *input_dev; 825 struct ads7846_platform_data *pdata = spi->dev.platform_data; 826 struct spi_message *m; 827 struct spi_transfer *x; 828 int vref; 829 int err; 830 831 if (!spi->irq) { 832 dev_dbg(&spi->dev, "no IRQ?\n"); 833 return -ENODEV; 834 } 835 836 if (!pdata) { 837 dev_dbg(&spi->dev, "no platform data?\n"); 838 return -ENODEV; 839 } 840 841 /* don't exceed max specified sample rate */ 842 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { 843 dev_dbg(&spi->dev, "f(sample) %d KHz?\n", 844 (spi->max_speed_hz/SAMPLE_BITS)/1000); 845 return -EINVAL; 846 } 847 848 /* REVISIT when the irq can be triggered active-low, or if for some 849 * reason the touchscreen isn't hooked up, we don't need to access 850 * the pendown state. 851 */ 852 if (pdata->get_pendown_state == NULL) { 853 dev_dbg(&spi->dev, "no get_pendown_state function?\n"); 854 return -EINVAL; 855 } 856 857 /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except 858 * that even if the hardware can do that, the SPI controller driver 859 * may not. So we stick to very-portable 8 bit words, both RX and TX. 860 */ 861 spi->bits_per_word = 8; 862 spi->mode = SPI_MODE_0; 863 err = spi_setup(spi); 864 if (err < 0) 865 return err; 866 867 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); 868 input_dev = input_allocate_device(); 869 if (!ts || !input_dev) { 870 err = -ENOMEM; 871 goto err_free_mem; 872 } 873 874 dev_set_drvdata(&spi->dev, ts); 875 876 ts->spi = spi; 877 ts->input = input_dev; 878 879 hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); 880 ts->timer.function = ads7846_timer; 881 882 spin_lock_init(&ts->lock); 883 884 ts->model = pdata->model ? : 7846; 885 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; 886 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; 887 ts->pressure_max = pdata->pressure_max ? : ~0; 888 889 if (pdata->filter != NULL) { 890 if (pdata->filter_init != NULL) { 891 err = pdata->filter_init(pdata, &ts->filter_data); 892 if (err < 0) 893 goto err_free_mem; 894 } 895 ts->filter = pdata->filter; 896 ts->filter_cleanup = pdata->filter_cleanup; 897 } else if (pdata->debounce_max) { 898 ts->debounce_max = pdata->debounce_max; 899 if (ts->debounce_max < 2) 900 ts->debounce_max = 2; 901 ts->debounce_tol = pdata->debounce_tol; 902 ts->debounce_rep = pdata->debounce_rep; 903 ts->filter = ads7846_debounce; 904 ts->filter_data = ts; 905 } else 906 ts->filter = ads7846_no_filter; 907 ts->get_pendown_state = pdata->get_pendown_state; 908 909 if (pdata->penirq_recheck_delay_usecs) 910 ts->penirq_recheck_delay_usecs = 911 pdata->penirq_recheck_delay_usecs; 912 913 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id); 914 915 input_dev->name = "ADS784x Touchscreen"; 916 input_dev->phys = ts->phys; 917 input_dev->dev.parent = &spi->dev; 918 919 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 920 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 921 input_set_abs_params(input_dev, ABS_X, 922 pdata->x_min ? : 0, 923 pdata->x_max ? : MAX_12BIT, 924 0, 0); 925 input_set_abs_params(input_dev, ABS_Y, 926 pdata->y_min ? : 0, 927 pdata->y_max ? : MAX_12BIT, 928 0, 0); 929 input_set_abs_params(input_dev, ABS_PRESSURE, 930 pdata->pressure_min, pdata->pressure_max, 0, 0); 931 932 vref = pdata->keep_vref_on; 933 934 /* set up the transfers to read touchscreen state; this assumes we 935 * use formula #2 for pressure, not #3. 936 */ 937 m = &ts->msg[0]; 938 x = ts->xfer; 939 940 spi_message_init(m); 941 942 /* y- still on; turn on only y+ (and ADC) */ 943 ts->read_y = READ_Y(vref); 944 x->tx_buf = &ts->read_y; 945 x->len = 1; 946 spi_message_add_tail(x, m); 947 948 x++; 949 x->rx_buf = &ts->tc.y; 950 x->len = 2; 951 spi_message_add_tail(x, m); 952 953 /* the first sample after switching drivers can be low quality; 954 * optionally discard it, using a second one after the signals 955 * have had enough time to stabilize. 956 */ 957 if (pdata->settle_delay_usecs) { 958 x->delay_usecs = pdata->settle_delay_usecs; 959 960 x++; 961 x->tx_buf = &ts->read_y; 962 x->len = 1; 963 spi_message_add_tail(x, m); 964 965 x++; 966 x->rx_buf = &ts->tc.y; 967 x->len = 2; 968 spi_message_add_tail(x, m); 969 } 970 971 m->complete = ads7846_rx_val; 972 m->context = ts; 973 974 m++; 975 spi_message_init(m); 976 977 /* turn y- off, x+ on, then leave in lowpower */ 978 x++; 979 ts->read_x = READ_X(vref); 980 x->tx_buf = &ts->read_x; 981 x->len = 1; 982 spi_message_add_tail(x, m); 983 984 x++; 985 x->rx_buf = &ts->tc.x; 986 x->len = 2; 987 spi_message_add_tail(x, m); 988 989 /* ... maybe discard first sample ... */ 990 if (pdata->settle_delay_usecs) { 991 x->delay_usecs = pdata->settle_delay_usecs; 992 993 x++; 994 x->tx_buf = &ts->read_x; 995 x->len = 1; 996 spi_message_add_tail(x, m); 997 998 x++; 999 x->rx_buf = &ts->tc.x; 1000 x->len = 2; 1001 spi_message_add_tail(x, m); 1002 } 1003 1004 m->complete = ads7846_rx_val; 1005 m->context = ts; 1006 1007 /* turn y+ off, x- on; we'll use formula #2 */ 1008 if (ts->model == 7846) { 1009 m++; 1010 spi_message_init(m); 1011 1012 x++; 1013 ts->read_z1 = READ_Z1(vref); 1014 x->tx_buf = &ts->read_z1; 1015 x->len = 1; 1016 spi_message_add_tail(x, m); 1017 1018 x++; 1019 x->rx_buf = &ts->tc.z1; 1020 x->len = 2; 1021 spi_message_add_tail(x, m); 1022 1023 /* ... maybe discard first sample ... */ 1024 if (pdata->settle_delay_usecs) { 1025 x->delay_usecs = pdata->settle_delay_usecs; 1026 1027 x++; 1028 x->tx_buf = &ts->read_z1; 1029 x->len = 1; 1030 spi_message_add_tail(x, m); 1031 1032 x++; 1033 x->rx_buf = &ts->tc.z1; 1034 x->len = 2; 1035 spi_message_add_tail(x, m); 1036 } 1037 1038 m->complete = ads7846_rx_val; 1039 m->context = ts; 1040 1041 m++; 1042 spi_message_init(m); 1043 1044 x++; 1045 ts->read_z2 = READ_Z2(vref); 1046 x->tx_buf = &ts->read_z2; 1047 x->len = 1; 1048 spi_message_add_tail(x, m); 1049 1050 x++; 1051 x->rx_buf = &ts->tc.z2; 1052 x->len = 2; 1053 spi_message_add_tail(x, m); 1054 1055 /* ... maybe discard first sample ... */ 1056 if (pdata->settle_delay_usecs) { 1057 x->delay_usecs = pdata->settle_delay_usecs; 1058 1059 x++; 1060 x->tx_buf = &ts->read_z2; 1061 x->len = 1; 1062 spi_message_add_tail(x, m); 1063 1064 x++; 1065 x->rx_buf = &ts->tc.z2; 1066 x->len = 2; 1067 spi_message_add_tail(x, m); 1068 } 1069 1070 m->complete = ads7846_rx_val; 1071 m->context = ts; 1072 } 1073 1074 /* power down */ 1075 m++; 1076 spi_message_init(m); 1077 1078 x++; 1079 ts->pwrdown = PWRDOWN; 1080 x->tx_buf = &ts->pwrdown; 1081 x->len = 1; 1082 spi_message_add_tail(x, m); 1083 1084 x++; 1085 x->rx_buf = &ts->dummy; 1086 x->len = 2; 1087 CS_CHANGE(*x); 1088 spi_message_add_tail(x, m); 1089 1090 m->complete = ads7846_rx; 1091 m->context = ts; 1092 1093 ts->last_msg = m; 1094 1095 if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING, 1096 spi->dev.driver->name, ts)) { 1097 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); 1098 err = -EBUSY; 1099 goto err_cleanup_filter; 1100 } 1101 1102 err = ads784x_hwmon_register(spi, ts); 1103 if (err) 1104 goto err_free_irq; 1105 1106 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); 1107 1108 /* take a first sample, leaving nPENIRQ active and vREF off; avoid 1109 * the touchscreen, in case it's not connected. 1110 */ 1111 (void) ads7846_read12_ser(&spi->dev, 1112 READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON); 1113 1114 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); 1115 if (err) 1116 goto err_remove_hwmon; 1117 1118 err = input_register_device(input_dev); 1119 if (err) 1120 goto err_remove_attr_group; 1121 1122 return 0; 1123 1124 err_remove_attr_group: 1125 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1126 err_remove_hwmon: 1127 ads784x_hwmon_unregister(spi, ts); 1128 err_free_irq: 1129 free_irq(spi->irq, ts); 1130 err_cleanup_filter: 1131 if (ts->filter_cleanup) 1132 ts->filter_cleanup(ts->filter_data); 1133 err_free_mem: 1134 input_free_device(input_dev); 1135 kfree(ts); 1136 return err; 1137 } 1138 1139 static int __devexit ads7846_remove(struct spi_device *spi) 1140 { 1141 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 1142 1143 ads784x_hwmon_unregister(spi, ts); 1144 input_unregister_device(ts->input); 1145 1146 ads7846_suspend(spi, PMSG_SUSPEND); 1147 1148 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1149 1150 free_irq(ts->spi->irq, ts); 1151 /* suspend left the IRQ disabled */ 1152 enable_irq(ts->spi->irq); 1153 1154 if (ts->filter_cleanup) 1155 ts->filter_cleanup(ts->filter_data); 1156 1157 kfree(ts); 1158 1159 dev_dbg(&spi->dev, "unregistered touchscreen\n"); 1160 return 0; 1161 } 1162 1163 static struct spi_driver ads7846_driver = { 1164 .driver = { 1165 .name = "ads7846", 1166 .bus = &spi_bus_type, 1167 .owner = THIS_MODULE, 1168 }, 1169 .probe = ads7846_probe, 1170 .remove = __devexit_p(ads7846_remove), 1171 .suspend = ads7846_suspend, 1172 .resume = ads7846_resume, 1173 }; 1174 1175 static int __init ads7846_init(void) 1176 { 1177 /* grr, board-specific init should stay out of drivers!! */ 1178 1179 #ifdef CONFIG_ARCH_OMAP 1180 if (machine_is_omap_osk()) { 1181 /* GPIO4 = PENIRQ; GPIO6 = BUSY */ 1182 omap_request_gpio(4); 1183 omap_set_gpio_direction(4, 1); 1184 omap_request_gpio(6); 1185 omap_set_gpio_direction(6, 1); 1186 } 1187 // also TI 1510 Innovator, bitbanging through FPGA 1188 // also Nokia 770 1189 // also Palm Tungsten T2 1190 #endif 1191 1192 // PXA: 1193 // also Dell Axim X50 1194 // also HP iPaq H191x/H192x/H415x/H435x 1195 // also Intel Lubbock (additional to UCB1400; as temperature sensor) 1196 // also Sharp Zaurus C7xx, C8xx (corgi/sheperd/husky) 1197 1198 // Atmel at91sam9261-EK uses ads7843 1199 1200 // also various AMD Au1x00 devel boards 1201 1202 return spi_register_driver(&ads7846_driver); 1203 } 1204 module_init(ads7846_init); 1205 1206 static void __exit ads7846_exit(void) 1207 { 1208 spi_unregister_driver(&ads7846_driver); 1209 1210 #ifdef CONFIG_ARCH_OMAP 1211 if (machine_is_omap_osk()) { 1212 omap_free_gpio(4); 1213 omap_free_gpio(6); 1214 } 1215 #endif 1216 1217 } 1218 module_exit(ads7846_exit); 1219 1220 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); 1221 MODULE_LICENSE("GPL"); 1222