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/types.h> 21 #include <linux/hwmon.h> 22 #include <linux/init.h> 23 #include <linux/err.h> 24 #include <linux/sched.h> 25 #include <linux/delay.h> 26 #include <linux/input.h> 27 #include <linux/interrupt.h> 28 #include <linux/slab.h> 29 #include <linux/pm.h> 30 #include <linux/gpio.h> 31 #include <linux/spi/spi.h> 32 #include <linux/spi/ads7846.h> 33 #include <linux/regulator/consumer.h> 34 #include <linux/module.h> 35 #include <asm/irq.h> 36 37 /* 38 * This code has been heavily tested on a Nokia 770, and lightly 39 * tested on other ads7846 devices (OSK/Mistral, Lubbock, Spitz). 40 * TSC2046 is just newer ads7846 silicon. 41 * Support for ads7843 tested on Atmel at91sam926x-EK. 42 * Support for ads7845 has only been stubbed in. 43 * Support for Analog Devices AD7873 and AD7843 tested. 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 /* ms delay before the first sample */ 60 #define TS_POLL_PERIOD 5 /* ms 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 /* 67 * For portability, we can't read 12 bit values using SPI (which 68 * would make the controller deliver them as native byte order 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 bool ignore; 76 u8 x_buf[3]; 77 u8 y_buf[3]; 78 }; 79 80 /* 81 * We allocate this separately to avoid cache line sharing issues when 82 * driver is used with DMA-based SPI controllers (like atmel_spi) on 83 * systems where main memory is not DMA-coherent (most non-x86 boards). 84 */ 85 struct ads7846_packet { 86 u8 read_x, read_y, read_z1, read_z2, pwrdown; 87 u16 dummy; /* for the pwrdown read */ 88 struct ts_event tc; 89 /* for ads7845 with mpc5121 psc spi we use 3-byte buffers */ 90 u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3]; 91 }; 92 93 struct ads7846 { 94 struct input_dev *input; 95 char phys[32]; 96 char name[32]; 97 98 struct spi_device *spi; 99 struct regulator *reg; 100 101 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 102 struct attribute_group *attr_group; 103 struct device *hwmon; 104 #endif 105 106 u16 model; 107 u16 vref_mv; 108 u16 vref_delay_usecs; 109 u16 x_plate_ohms; 110 u16 pressure_max; 111 112 bool swap_xy; 113 bool use_internal; 114 115 struct ads7846_packet *packet; 116 117 struct spi_transfer xfer[18]; 118 struct spi_message msg[5]; 119 int msg_count; 120 wait_queue_head_t wait; 121 122 bool pendown; 123 124 int read_cnt; 125 int read_rep; 126 int last_read; 127 128 u16 debounce_max; 129 u16 debounce_tol; 130 u16 debounce_rep; 131 132 u16 penirq_recheck_delay_usecs; 133 134 struct mutex lock; 135 bool stopped; /* P: lock */ 136 bool disabled; /* P: lock */ 137 bool suspended; /* P: lock */ 138 139 int (*filter)(void *data, int data_idx, int *val); 140 void *filter_data; 141 void (*filter_cleanup)(void *data); 142 int (*get_pendown_state)(void); 143 int gpio_pendown; 144 145 void (*wait_for_sync)(void); 146 }; 147 148 /* leave chip selected when we're done, for quicker re-select? */ 149 #if 0 150 #define CS_CHANGE(xfer) ((xfer).cs_change = 1) 151 #else 152 #define CS_CHANGE(xfer) ((xfer).cs_change = 0) 153 #endif 154 155 /*--------------------------------------------------------------------------*/ 156 157 /* The ADS7846 has touchscreen and other sensors. 158 * Earlier ads784x chips are somewhat compatible. 159 */ 160 #define ADS_START (1 << 7) 161 #define ADS_A2A1A0_d_y (1 << 4) /* differential */ 162 #define ADS_A2A1A0_d_z1 (3 << 4) /* differential */ 163 #define ADS_A2A1A0_d_z2 (4 << 4) /* differential */ 164 #define ADS_A2A1A0_d_x (5 << 4) /* differential */ 165 #define ADS_A2A1A0_temp0 (0 << 4) /* non-differential */ 166 #define ADS_A2A1A0_vbatt (2 << 4) /* non-differential */ 167 #define ADS_A2A1A0_vaux (6 << 4) /* non-differential */ 168 #define ADS_A2A1A0_temp1 (7 << 4) /* non-differential */ 169 #define ADS_8_BIT (1 << 3) 170 #define ADS_12_BIT (0 << 3) 171 #define ADS_SER (1 << 2) /* non-differential */ 172 #define ADS_DFR (0 << 2) /* differential */ 173 #define ADS_PD10_PDOWN (0 << 0) /* low power mode + penirq */ 174 #define ADS_PD10_ADC_ON (1 << 0) /* ADC on */ 175 #define ADS_PD10_REF_ON (2 << 0) /* vREF on + penirq */ 176 #define ADS_PD10_ALL_ON (3 << 0) /* ADC + vREF on */ 177 178 #define MAX_12BIT ((1<<12)-1) 179 180 /* leave ADC powered up (disables penirq) between differential samples */ 181 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \ 182 | ADS_12_BIT | ADS_DFR | \ 183 (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0)) 184 185 #define READ_Y(vref) (READ_12BIT_DFR(y, 1, vref)) 186 #define READ_Z1(vref) (READ_12BIT_DFR(z1, 1, vref)) 187 #define READ_Z2(vref) (READ_12BIT_DFR(z2, 1, vref)) 188 189 #define READ_X(vref) (READ_12BIT_DFR(x, 1, vref)) 190 #define PWRDOWN (READ_12BIT_DFR(y, 0, 0)) /* LAST */ 191 192 /* single-ended samples need to first power up reference voltage; 193 * we leave both ADC and VREF powered 194 */ 195 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \ 196 | ADS_12_BIT | ADS_SER) 197 198 #define REF_ON (READ_12BIT_DFR(x, 1, 1)) 199 #define REF_OFF (READ_12BIT_DFR(y, 0, 0)) 200 201 /* Must be called with ts->lock held */ 202 static void ads7846_stop(struct ads7846 *ts) 203 { 204 if (!ts->disabled && !ts->suspended) { 205 /* Signal IRQ thread to stop polling and disable the handler. */ 206 ts->stopped = true; 207 mb(); 208 wake_up(&ts->wait); 209 disable_irq(ts->spi->irq); 210 } 211 } 212 213 /* Must be called with ts->lock held */ 214 static void ads7846_restart(struct ads7846 *ts) 215 { 216 if (!ts->disabled && !ts->suspended) { 217 /* Tell IRQ thread that it may poll the device. */ 218 ts->stopped = false; 219 mb(); 220 enable_irq(ts->spi->irq); 221 } 222 } 223 224 /* Must be called with ts->lock held */ 225 static void __ads7846_disable(struct ads7846 *ts) 226 { 227 ads7846_stop(ts); 228 regulator_disable(ts->reg); 229 230 /* 231 * We know the chip's in low power mode since we always 232 * leave it that way after every request 233 */ 234 } 235 236 /* Must be called with ts->lock held */ 237 static void __ads7846_enable(struct ads7846 *ts) 238 { 239 int error; 240 241 error = regulator_enable(ts->reg); 242 if (error != 0) 243 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error); 244 245 ads7846_restart(ts); 246 } 247 248 static void ads7846_disable(struct ads7846 *ts) 249 { 250 mutex_lock(&ts->lock); 251 252 if (!ts->disabled) { 253 254 if (!ts->suspended) 255 __ads7846_disable(ts); 256 257 ts->disabled = true; 258 } 259 260 mutex_unlock(&ts->lock); 261 } 262 263 static void ads7846_enable(struct ads7846 *ts) 264 { 265 mutex_lock(&ts->lock); 266 267 if (ts->disabled) { 268 269 ts->disabled = false; 270 271 if (!ts->suspended) 272 __ads7846_enable(ts); 273 } 274 275 mutex_unlock(&ts->lock); 276 } 277 278 /*--------------------------------------------------------------------------*/ 279 280 /* 281 * Non-touchscreen sensors only use single-ended conversions. 282 * The range is GND..vREF. The ads7843 and ads7835 must use external vREF; 283 * ads7846 lets that pin be unconnected, to use internal vREF. 284 */ 285 286 struct ser_req { 287 u8 ref_on; 288 u8 command; 289 u8 ref_off; 290 u16 scratch; 291 struct spi_message msg; 292 struct spi_transfer xfer[6]; 293 /* 294 * DMA (thus cache coherency maintenance) requires the 295 * transfer buffers to live in their own cache lines. 296 */ 297 __be16 sample ____cacheline_aligned; 298 }; 299 300 struct ads7845_ser_req { 301 u8 command[3]; 302 struct spi_message msg; 303 struct spi_transfer xfer[2]; 304 /* 305 * DMA (thus cache coherency maintenance) requires the 306 * transfer buffers to live in their own cache lines. 307 */ 308 u8 sample[3] ____cacheline_aligned; 309 }; 310 311 static int ads7846_read12_ser(struct device *dev, unsigned command) 312 { 313 struct spi_device *spi = to_spi_device(dev); 314 struct ads7846 *ts = dev_get_drvdata(dev); 315 struct ser_req *req; 316 int status; 317 318 req = kzalloc(sizeof *req, GFP_KERNEL); 319 if (!req) 320 return -ENOMEM; 321 322 spi_message_init(&req->msg); 323 324 /* maybe turn on internal vREF, and let it settle */ 325 if (ts->use_internal) { 326 req->ref_on = REF_ON; 327 req->xfer[0].tx_buf = &req->ref_on; 328 req->xfer[0].len = 1; 329 spi_message_add_tail(&req->xfer[0], &req->msg); 330 331 req->xfer[1].rx_buf = &req->scratch; 332 req->xfer[1].len = 2; 333 334 /* for 1uF, settle for 800 usec; no cap, 100 usec. */ 335 req->xfer[1].delay_usecs = ts->vref_delay_usecs; 336 spi_message_add_tail(&req->xfer[1], &req->msg); 337 338 /* Enable reference voltage */ 339 command |= ADS_PD10_REF_ON; 340 } 341 342 /* Enable ADC in every case */ 343 command |= ADS_PD10_ADC_ON; 344 345 /* take sample */ 346 req->command = (u8) command; 347 req->xfer[2].tx_buf = &req->command; 348 req->xfer[2].len = 1; 349 spi_message_add_tail(&req->xfer[2], &req->msg); 350 351 req->xfer[3].rx_buf = &req->sample; 352 req->xfer[3].len = 2; 353 spi_message_add_tail(&req->xfer[3], &req->msg); 354 355 /* REVISIT: take a few more samples, and compare ... */ 356 357 /* converter in low power mode & enable PENIRQ */ 358 req->ref_off = PWRDOWN; 359 req->xfer[4].tx_buf = &req->ref_off; 360 req->xfer[4].len = 1; 361 spi_message_add_tail(&req->xfer[4], &req->msg); 362 363 req->xfer[5].rx_buf = &req->scratch; 364 req->xfer[5].len = 2; 365 CS_CHANGE(req->xfer[5]); 366 spi_message_add_tail(&req->xfer[5], &req->msg); 367 368 mutex_lock(&ts->lock); 369 ads7846_stop(ts); 370 status = spi_sync(spi, &req->msg); 371 ads7846_restart(ts); 372 mutex_unlock(&ts->lock); 373 374 if (status == 0) { 375 /* on-wire is a must-ignore bit, a BE12 value, then padding */ 376 status = be16_to_cpu(req->sample); 377 status = status >> 3; 378 status &= 0x0fff; 379 } 380 381 kfree(req); 382 return status; 383 } 384 385 static int ads7845_read12_ser(struct device *dev, unsigned command) 386 { 387 struct spi_device *spi = to_spi_device(dev); 388 struct ads7846 *ts = dev_get_drvdata(dev); 389 struct ads7845_ser_req *req; 390 int status; 391 392 req = kzalloc(sizeof *req, GFP_KERNEL); 393 if (!req) 394 return -ENOMEM; 395 396 spi_message_init(&req->msg); 397 398 req->command[0] = (u8) command; 399 req->xfer[0].tx_buf = req->command; 400 req->xfer[0].rx_buf = req->sample; 401 req->xfer[0].len = 3; 402 spi_message_add_tail(&req->xfer[0], &req->msg); 403 404 mutex_lock(&ts->lock); 405 ads7846_stop(ts); 406 status = spi_sync(spi, &req->msg); 407 ads7846_restart(ts); 408 mutex_unlock(&ts->lock); 409 410 if (status == 0) { 411 /* BE12 value, then padding */ 412 status = be16_to_cpu(*((u16 *)&req->sample[1])); 413 status = status >> 3; 414 status &= 0x0fff; 415 } 416 417 kfree(req); 418 return status; 419 } 420 421 #if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE) 422 423 #define SHOW(name, var, adjust) static ssize_t \ 424 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \ 425 { \ 426 struct ads7846 *ts = dev_get_drvdata(dev); \ 427 ssize_t v = ads7846_read12_ser(dev, \ 428 READ_12BIT_SER(var)); \ 429 if (v < 0) \ 430 return v; \ 431 return sprintf(buf, "%u\n", adjust(ts, v)); \ 432 } \ 433 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL); 434 435 436 /* Sysfs conventions report temperatures in millidegrees Celsius. 437 * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high 438 * accuracy scheme without calibration data. For now we won't try either; 439 * userspace sees raw sensor values, and must scale/calibrate appropriately. 440 */ 441 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v) 442 { 443 return v; 444 } 445 446 SHOW(temp0, temp0, null_adjust) /* temp1_input */ 447 SHOW(temp1, temp1, null_adjust) /* temp2_input */ 448 449 450 /* sysfs conventions report voltages in millivolts. We can convert voltages 451 * if we know vREF. userspace may need to scale vAUX to match the board's 452 * external resistors; we assume that vBATT only uses the internal ones. 453 */ 454 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v) 455 { 456 unsigned retval = v; 457 458 /* external resistors may scale vAUX into 0..vREF */ 459 retval *= ts->vref_mv; 460 retval = retval >> 12; 461 462 return retval; 463 } 464 465 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v) 466 { 467 unsigned retval = vaux_adjust(ts, v); 468 469 /* ads7846 has a resistor ladder to scale this signal down */ 470 if (ts->model == 7846) 471 retval *= 4; 472 473 return retval; 474 } 475 476 SHOW(in0_input, vaux, vaux_adjust) 477 SHOW(in1_input, vbatt, vbatt_adjust) 478 479 static struct attribute *ads7846_attributes[] = { 480 &dev_attr_temp0.attr, 481 &dev_attr_temp1.attr, 482 &dev_attr_in0_input.attr, 483 &dev_attr_in1_input.attr, 484 NULL, 485 }; 486 487 static struct attribute_group ads7846_attr_group = { 488 .attrs = ads7846_attributes, 489 }; 490 491 static struct attribute *ads7843_attributes[] = { 492 &dev_attr_in0_input.attr, 493 &dev_attr_in1_input.attr, 494 NULL, 495 }; 496 497 static struct attribute_group ads7843_attr_group = { 498 .attrs = ads7843_attributes, 499 }; 500 501 static struct attribute *ads7845_attributes[] = { 502 &dev_attr_in0_input.attr, 503 NULL, 504 }; 505 506 static struct attribute_group ads7845_attr_group = { 507 .attrs = ads7845_attributes, 508 }; 509 510 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts) 511 { 512 struct device *hwmon; 513 int err; 514 515 /* hwmon sensors need a reference voltage */ 516 switch (ts->model) { 517 case 7846: 518 if (!ts->vref_mv) { 519 dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n"); 520 ts->vref_mv = 2500; 521 ts->use_internal = true; 522 } 523 break; 524 case 7845: 525 case 7843: 526 if (!ts->vref_mv) { 527 dev_warn(&spi->dev, 528 "external vREF for ADS%d not specified\n", 529 ts->model); 530 return 0; 531 } 532 break; 533 } 534 535 /* different chips have different sensor groups */ 536 switch (ts->model) { 537 case 7846: 538 ts->attr_group = &ads7846_attr_group; 539 break; 540 case 7845: 541 ts->attr_group = &ads7845_attr_group; 542 break; 543 case 7843: 544 ts->attr_group = &ads7843_attr_group; 545 break; 546 default: 547 dev_dbg(&spi->dev, "ADS%d not recognized\n", ts->model); 548 return 0; 549 } 550 551 err = sysfs_create_group(&spi->dev.kobj, ts->attr_group); 552 if (err) 553 return err; 554 555 hwmon = hwmon_device_register(&spi->dev); 556 if (IS_ERR(hwmon)) { 557 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 558 return PTR_ERR(hwmon); 559 } 560 561 ts->hwmon = hwmon; 562 return 0; 563 } 564 565 static void ads784x_hwmon_unregister(struct spi_device *spi, 566 struct ads7846 *ts) 567 { 568 if (ts->hwmon) { 569 sysfs_remove_group(&spi->dev.kobj, ts->attr_group); 570 hwmon_device_unregister(ts->hwmon); 571 } 572 } 573 574 #else 575 static inline int ads784x_hwmon_register(struct spi_device *spi, 576 struct ads7846 *ts) 577 { 578 return 0; 579 } 580 581 static inline void ads784x_hwmon_unregister(struct spi_device *spi, 582 struct ads7846 *ts) 583 { 584 } 585 #endif 586 587 static ssize_t ads7846_pen_down_show(struct device *dev, 588 struct device_attribute *attr, char *buf) 589 { 590 struct ads7846 *ts = dev_get_drvdata(dev); 591 592 return sprintf(buf, "%u\n", ts->pendown); 593 } 594 595 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL); 596 597 static ssize_t ads7846_disable_show(struct device *dev, 598 struct device_attribute *attr, char *buf) 599 { 600 struct ads7846 *ts = dev_get_drvdata(dev); 601 602 return sprintf(buf, "%u\n", ts->disabled); 603 } 604 605 static ssize_t ads7846_disable_store(struct device *dev, 606 struct device_attribute *attr, 607 const char *buf, size_t count) 608 { 609 struct ads7846 *ts = dev_get_drvdata(dev); 610 unsigned int i; 611 int err; 612 613 err = kstrtouint(buf, 10, &i); 614 if (err) 615 return err; 616 617 if (i) 618 ads7846_disable(ts); 619 else 620 ads7846_enable(ts); 621 622 return count; 623 } 624 625 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store); 626 627 static struct attribute *ads784x_attributes[] = { 628 &dev_attr_pen_down.attr, 629 &dev_attr_disable.attr, 630 NULL, 631 }; 632 633 static struct attribute_group ads784x_attr_group = { 634 .attrs = ads784x_attributes, 635 }; 636 637 /*--------------------------------------------------------------------------*/ 638 639 static int get_pendown_state(struct ads7846 *ts) 640 { 641 if (ts->get_pendown_state) 642 return ts->get_pendown_state(); 643 644 return !gpio_get_value(ts->gpio_pendown); 645 } 646 647 static void null_wait_for_sync(void) 648 { 649 } 650 651 static int ads7846_debounce_filter(void *ads, int data_idx, int *val) 652 { 653 struct ads7846 *ts = ads; 654 655 if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) { 656 /* Start over collecting consistent readings. */ 657 ts->read_rep = 0; 658 /* 659 * Repeat it, if this was the first read or the read 660 * wasn't consistent enough. 661 */ 662 if (ts->read_cnt < ts->debounce_max) { 663 ts->last_read = *val; 664 ts->read_cnt++; 665 return ADS7846_FILTER_REPEAT; 666 } else { 667 /* 668 * Maximum number of debouncing reached and still 669 * not enough number of consistent readings. Abort 670 * the whole sample, repeat it in the next sampling 671 * period. 672 */ 673 ts->read_cnt = 0; 674 return ADS7846_FILTER_IGNORE; 675 } 676 } else { 677 if (++ts->read_rep > ts->debounce_rep) { 678 /* 679 * Got a good reading for this coordinate, 680 * go for the next one. 681 */ 682 ts->read_cnt = 0; 683 ts->read_rep = 0; 684 return ADS7846_FILTER_OK; 685 } else { 686 /* Read more values that are consistent. */ 687 ts->read_cnt++; 688 return ADS7846_FILTER_REPEAT; 689 } 690 } 691 } 692 693 static int ads7846_no_filter(void *ads, int data_idx, int *val) 694 { 695 return ADS7846_FILTER_OK; 696 } 697 698 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m) 699 { 700 struct spi_transfer *t = 701 list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 702 703 if (ts->model == 7845) { 704 return be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3; 705 } else { 706 /* 707 * adjust: on-wire is a must-ignore bit, a BE12 value, then 708 * padding; built from two 8 bit values written msb-first. 709 */ 710 return be16_to_cpup((__be16 *)t->rx_buf) >> 3; 711 } 712 } 713 714 static void ads7846_update_value(struct spi_message *m, int val) 715 { 716 struct spi_transfer *t = 717 list_entry(m->transfers.prev, struct spi_transfer, transfer_list); 718 719 *(u16 *)t->rx_buf = val; 720 } 721 722 static void ads7846_read_state(struct ads7846 *ts) 723 { 724 struct ads7846_packet *packet = ts->packet; 725 struct spi_message *m; 726 int msg_idx = 0; 727 int val; 728 int action; 729 int error; 730 731 while (msg_idx < ts->msg_count) { 732 733 ts->wait_for_sync(); 734 735 m = &ts->msg[msg_idx]; 736 error = spi_sync(ts->spi, m); 737 if (error) { 738 dev_err(&ts->spi->dev, "spi_async --> %d\n", error); 739 packet->tc.ignore = true; 740 return; 741 } 742 743 /* 744 * Last message is power down request, no need to convert 745 * or filter the value. 746 */ 747 if (msg_idx < ts->msg_count - 1) { 748 749 val = ads7846_get_value(ts, m); 750 751 action = ts->filter(ts->filter_data, msg_idx, &val); 752 switch (action) { 753 case ADS7846_FILTER_REPEAT: 754 continue; 755 756 case ADS7846_FILTER_IGNORE: 757 packet->tc.ignore = true; 758 msg_idx = ts->msg_count - 1; 759 continue; 760 761 case ADS7846_FILTER_OK: 762 ads7846_update_value(m, val); 763 packet->tc.ignore = false; 764 msg_idx++; 765 break; 766 767 default: 768 BUG(); 769 } 770 } else { 771 msg_idx++; 772 } 773 } 774 } 775 776 static void ads7846_report_state(struct ads7846 *ts) 777 { 778 struct ads7846_packet *packet = ts->packet; 779 unsigned int Rt; 780 u16 x, y, z1, z2; 781 782 /* 783 * ads7846_get_value() does in-place conversion (including byte swap) 784 * from on-the-wire format as part of debouncing to get stable 785 * readings. 786 */ 787 if (ts->model == 7845) { 788 x = *(u16 *)packet->tc.x_buf; 789 y = *(u16 *)packet->tc.y_buf; 790 z1 = 0; 791 z2 = 0; 792 } else { 793 x = packet->tc.x; 794 y = packet->tc.y; 795 z1 = packet->tc.z1; 796 z2 = packet->tc.z2; 797 } 798 799 /* range filtering */ 800 if (x == MAX_12BIT) 801 x = 0; 802 803 if (ts->model == 7843) { 804 Rt = ts->pressure_max / 2; 805 } else if (ts->model == 7845) { 806 if (get_pendown_state(ts)) 807 Rt = ts->pressure_max / 2; 808 else 809 Rt = 0; 810 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt); 811 } else if (likely(x && z1)) { 812 /* compute touch pressure resistance using equation #2 */ 813 Rt = z2; 814 Rt -= z1; 815 Rt *= x; 816 Rt *= ts->x_plate_ohms; 817 Rt /= z1; 818 Rt = (Rt + 2047) >> 12; 819 } else { 820 Rt = 0; 821 } 822 823 /* 824 * Sample found inconsistent by debouncing or pressure is beyond 825 * the maximum. Don't report it to user space, repeat at least 826 * once more the measurement 827 */ 828 if (packet->tc.ignore || Rt > ts->pressure_max) { 829 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n", 830 packet->tc.ignore, Rt); 831 return; 832 } 833 834 /* 835 * Maybe check the pendown state before reporting. This discards 836 * false readings when the pen is lifted. 837 */ 838 if (ts->penirq_recheck_delay_usecs) { 839 udelay(ts->penirq_recheck_delay_usecs); 840 if (!get_pendown_state(ts)) 841 Rt = 0; 842 } 843 844 /* 845 * NOTE: We can't rely on the pressure to determine the pen down 846 * state, even this controller has a pressure sensor. The pressure 847 * value can fluctuate for quite a while after lifting the pen and 848 * in some cases may not even settle at the expected value. 849 * 850 * The only safe way to check for the pen up condition is in the 851 * timer by reading the pen signal state (it's a GPIO _and_ IRQ). 852 */ 853 if (Rt) { 854 struct input_dev *input = ts->input; 855 856 if (ts->swap_xy) 857 swap(x, y); 858 859 if (!ts->pendown) { 860 input_report_key(input, BTN_TOUCH, 1); 861 ts->pendown = true; 862 dev_vdbg(&ts->spi->dev, "DOWN\n"); 863 } 864 865 input_report_abs(input, ABS_X, x); 866 input_report_abs(input, ABS_Y, y); 867 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt); 868 869 input_sync(input); 870 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt); 871 } 872 } 873 874 static irqreturn_t ads7846_hard_irq(int irq, void *handle) 875 { 876 struct ads7846 *ts = handle; 877 878 return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED; 879 } 880 881 882 static irqreturn_t ads7846_irq(int irq, void *handle) 883 { 884 struct ads7846 *ts = handle; 885 886 /* Start with a small delay before checking pendown state */ 887 msleep(TS_POLL_DELAY); 888 889 while (!ts->stopped && get_pendown_state(ts)) { 890 891 /* pen is down, continue with the measurement */ 892 ads7846_read_state(ts); 893 894 if (!ts->stopped) 895 ads7846_report_state(ts); 896 897 wait_event_timeout(ts->wait, ts->stopped, 898 msecs_to_jiffies(TS_POLL_PERIOD)); 899 } 900 901 if (ts->pendown) { 902 struct input_dev *input = ts->input; 903 904 input_report_key(input, BTN_TOUCH, 0); 905 input_report_abs(input, ABS_PRESSURE, 0); 906 input_sync(input); 907 908 ts->pendown = false; 909 dev_vdbg(&ts->spi->dev, "UP\n"); 910 } 911 912 return IRQ_HANDLED; 913 } 914 915 #ifdef CONFIG_PM_SLEEP 916 static int ads7846_suspend(struct device *dev) 917 { 918 struct ads7846 *ts = dev_get_drvdata(dev); 919 920 mutex_lock(&ts->lock); 921 922 if (!ts->suspended) { 923 924 if (!ts->disabled) 925 __ads7846_disable(ts); 926 927 if (device_may_wakeup(&ts->spi->dev)) 928 enable_irq_wake(ts->spi->irq); 929 930 ts->suspended = true; 931 } 932 933 mutex_unlock(&ts->lock); 934 935 return 0; 936 } 937 938 static int ads7846_resume(struct device *dev) 939 { 940 struct ads7846 *ts = dev_get_drvdata(dev); 941 942 mutex_lock(&ts->lock); 943 944 if (ts->suspended) { 945 946 ts->suspended = false; 947 948 if (device_may_wakeup(&ts->spi->dev)) 949 disable_irq_wake(ts->spi->irq); 950 951 if (!ts->disabled) 952 __ads7846_enable(ts); 953 } 954 955 mutex_unlock(&ts->lock); 956 957 return 0; 958 } 959 #endif 960 961 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume); 962 963 static int ads7846_setup_pendown(struct spi_device *spi, 964 struct ads7846 *ts) 965 { 966 struct ads7846_platform_data *pdata = spi->dev.platform_data; 967 int err; 968 969 /* 970 * REVISIT when the irq can be triggered active-low, or if for some 971 * reason the touchscreen isn't hooked up, we don't need to access 972 * the pendown state. 973 */ 974 975 if (pdata->get_pendown_state) { 976 ts->get_pendown_state = pdata->get_pendown_state; 977 } else if (gpio_is_valid(pdata->gpio_pendown)) { 978 979 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN, 980 "ads7846_pendown"); 981 if (err) { 982 dev_err(&spi->dev, 983 "failed to request/setup pendown GPIO%d: %d\n", 984 pdata->gpio_pendown, err); 985 return err; 986 } 987 988 ts->gpio_pendown = pdata->gpio_pendown; 989 990 if (pdata->gpio_pendown_debounce) 991 gpio_set_debounce(pdata->gpio_pendown, 992 pdata->gpio_pendown_debounce); 993 } else { 994 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n"); 995 return -EINVAL; 996 } 997 998 return 0; 999 } 1000 1001 /* 1002 * Set up the transfers to read touchscreen state; this assumes we 1003 * use formula #2 for pressure, not #3. 1004 */ 1005 static void ads7846_setup_spi_msg(struct ads7846 *ts, 1006 const struct ads7846_platform_data *pdata) 1007 { 1008 struct spi_message *m = &ts->msg[0]; 1009 struct spi_transfer *x = ts->xfer; 1010 struct ads7846_packet *packet = ts->packet; 1011 int vref = pdata->keep_vref_on; 1012 1013 if (ts->model == 7873) { 1014 /* 1015 * The AD7873 is almost identical to the ADS7846 1016 * keep VREF off during differential/ratiometric 1017 * conversion modes. 1018 */ 1019 ts->model = 7846; 1020 vref = 0; 1021 } 1022 1023 ts->msg_count = 1; 1024 spi_message_init(m); 1025 m->context = ts; 1026 1027 if (ts->model == 7845) { 1028 packet->read_y_cmd[0] = READ_Y(vref); 1029 packet->read_y_cmd[1] = 0; 1030 packet->read_y_cmd[2] = 0; 1031 x->tx_buf = &packet->read_y_cmd[0]; 1032 x->rx_buf = &packet->tc.y_buf[0]; 1033 x->len = 3; 1034 spi_message_add_tail(x, m); 1035 } else { 1036 /* y- still on; turn on only y+ (and ADC) */ 1037 packet->read_y = READ_Y(vref); 1038 x->tx_buf = &packet->read_y; 1039 x->len = 1; 1040 spi_message_add_tail(x, m); 1041 1042 x++; 1043 x->rx_buf = &packet->tc.y; 1044 x->len = 2; 1045 spi_message_add_tail(x, m); 1046 } 1047 1048 /* 1049 * The first sample after switching drivers can be low quality; 1050 * optionally discard it, using a second one after the signals 1051 * have had enough time to stabilize. 1052 */ 1053 if (pdata->settle_delay_usecs) { 1054 x->delay_usecs = pdata->settle_delay_usecs; 1055 1056 x++; 1057 x->tx_buf = &packet->read_y; 1058 x->len = 1; 1059 spi_message_add_tail(x, m); 1060 1061 x++; 1062 x->rx_buf = &packet->tc.y; 1063 x->len = 2; 1064 spi_message_add_tail(x, m); 1065 } 1066 1067 ts->msg_count++; 1068 m++; 1069 spi_message_init(m); 1070 m->context = ts; 1071 1072 if (ts->model == 7845) { 1073 x++; 1074 packet->read_x_cmd[0] = READ_X(vref); 1075 packet->read_x_cmd[1] = 0; 1076 packet->read_x_cmd[2] = 0; 1077 x->tx_buf = &packet->read_x_cmd[0]; 1078 x->rx_buf = &packet->tc.x_buf[0]; 1079 x->len = 3; 1080 spi_message_add_tail(x, m); 1081 } else { 1082 /* turn y- off, x+ on, then leave in lowpower */ 1083 x++; 1084 packet->read_x = READ_X(vref); 1085 x->tx_buf = &packet->read_x; 1086 x->len = 1; 1087 spi_message_add_tail(x, m); 1088 1089 x++; 1090 x->rx_buf = &packet->tc.x; 1091 x->len = 2; 1092 spi_message_add_tail(x, m); 1093 } 1094 1095 /* ... maybe discard first sample ... */ 1096 if (pdata->settle_delay_usecs) { 1097 x->delay_usecs = pdata->settle_delay_usecs; 1098 1099 x++; 1100 x->tx_buf = &packet->read_x; 1101 x->len = 1; 1102 spi_message_add_tail(x, m); 1103 1104 x++; 1105 x->rx_buf = &packet->tc.x; 1106 x->len = 2; 1107 spi_message_add_tail(x, m); 1108 } 1109 1110 /* turn y+ off, x- on; we'll use formula #2 */ 1111 if (ts->model == 7846) { 1112 ts->msg_count++; 1113 m++; 1114 spi_message_init(m); 1115 m->context = ts; 1116 1117 x++; 1118 packet->read_z1 = READ_Z1(vref); 1119 x->tx_buf = &packet->read_z1; 1120 x->len = 1; 1121 spi_message_add_tail(x, m); 1122 1123 x++; 1124 x->rx_buf = &packet->tc.z1; 1125 x->len = 2; 1126 spi_message_add_tail(x, m); 1127 1128 /* ... maybe discard first sample ... */ 1129 if (pdata->settle_delay_usecs) { 1130 x->delay_usecs = pdata->settle_delay_usecs; 1131 1132 x++; 1133 x->tx_buf = &packet->read_z1; 1134 x->len = 1; 1135 spi_message_add_tail(x, m); 1136 1137 x++; 1138 x->rx_buf = &packet->tc.z1; 1139 x->len = 2; 1140 spi_message_add_tail(x, m); 1141 } 1142 1143 ts->msg_count++; 1144 m++; 1145 spi_message_init(m); 1146 m->context = ts; 1147 1148 x++; 1149 packet->read_z2 = READ_Z2(vref); 1150 x->tx_buf = &packet->read_z2; 1151 x->len = 1; 1152 spi_message_add_tail(x, m); 1153 1154 x++; 1155 x->rx_buf = &packet->tc.z2; 1156 x->len = 2; 1157 spi_message_add_tail(x, m); 1158 1159 /* ... maybe discard first sample ... */ 1160 if (pdata->settle_delay_usecs) { 1161 x->delay_usecs = pdata->settle_delay_usecs; 1162 1163 x++; 1164 x->tx_buf = &packet->read_z2; 1165 x->len = 1; 1166 spi_message_add_tail(x, m); 1167 1168 x++; 1169 x->rx_buf = &packet->tc.z2; 1170 x->len = 2; 1171 spi_message_add_tail(x, m); 1172 } 1173 } 1174 1175 /* power down */ 1176 ts->msg_count++; 1177 m++; 1178 spi_message_init(m); 1179 m->context = ts; 1180 1181 if (ts->model == 7845) { 1182 x++; 1183 packet->pwrdown_cmd[0] = PWRDOWN; 1184 packet->pwrdown_cmd[1] = 0; 1185 packet->pwrdown_cmd[2] = 0; 1186 x->tx_buf = &packet->pwrdown_cmd[0]; 1187 x->len = 3; 1188 } else { 1189 x++; 1190 packet->pwrdown = PWRDOWN; 1191 x->tx_buf = &packet->pwrdown; 1192 x->len = 1; 1193 spi_message_add_tail(x, m); 1194 1195 x++; 1196 x->rx_buf = &packet->dummy; 1197 x->len = 2; 1198 } 1199 1200 CS_CHANGE(*x); 1201 spi_message_add_tail(x, m); 1202 } 1203 1204 static int ads7846_probe(struct spi_device *spi) 1205 { 1206 struct ads7846 *ts; 1207 struct ads7846_packet *packet; 1208 struct input_dev *input_dev; 1209 struct ads7846_platform_data *pdata = spi->dev.platform_data; 1210 unsigned long irq_flags; 1211 int err; 1212 1213 if (!spi->irq) { 1214 dev_dbg(&spi->dev, "no IRQ?\n"); 1215 return -ENODEV; 1216 } 1217 1218 if (!pdata) { 1219 dev_dbg(&spi->dev, "no platform data?\n"); 1220 return -ENODEV; 1221 } 1222 1223 /* don't exceed max specified sample rate */ 1224 if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) { 1225 dev_dbg(&spi->dev, "f(sample) %d KHz?\n", 1226 (spi->max_speed_hz/SAMPLE_BITS)/1000); 1227 return -EINVAL; 1228 } 1229 1230 /* We'd set TX word size 8 bits and RX word size to 13 bits ... except 1231 * that even if the hardware can do that, the SPI controller driver 1232 * may not. So we stick to very-portable 8 bit words, both RX and TX. 1233 */ 1234 spi->bits_per_word = 8; 1235 spi->mode = SPI_MODE_0; 1236 err = spi_setup(spi); 1237 if (err < 0) 1238 return err; 1239 1240 ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL); 1241 packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL); 1242 input_dev = input_allocate_device(); 1243 if (!ts || !packet || !input_dev) { 1244 err = -ENOMEM; 1245 goto err_free_mem; 1246 } 1247 1248 dev_set_drvdata(&spi->dev, ts); 1249 1250 ts->packet = packet; 1251 ts->spi = spi; 1252 ts->input = input_dev; 1253 ts->vref_mv = pdata->vref_mv; 1254 ts->swap_xy = pdata->swap_xy; 1255 1256 mutex_init(&ts->lock); 1257 init_waitqueue_head(&ts->wait); 1258 1259 ts->model = pdata->model ? : 7846; 1260 ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100; 1261 ts->x_plate_ohms = pdata->x_plate_ohms ? : 400; 1262 ts->pressure_max = pdata->pressure_max ? : ~0; 1263 1264 if (pdata->filter != NULL) { 1265 if (pdata->filter_init != NULL) { 1266 err = pdata->filter_init(pdata, &ts->filter_data); 1267 if (err < 0) 1268 goto err_free_mem; 1269 } 1270 ts->filter = pdata->filter; 1271 ts->filter_cleanup = pdata->filter_cleanup; 1272 } else if (pdata->debounce_max) { 1273 ts->debounce_max = pdata->debounce_max; 1274 if (ts->debounce_max < 2) 1275 ts->debounce_max = 2; 1276 ts->debounce_tol = pdata->debounce_tol; 1277 ts->debounce_rep = pdata->debounce_rep; 1278 ts->filter = ads7846_debounce_filter; 1279 ts->filter_data = ts; 1280 } else { 1281 ts->filter = ads7846_no_filter; 1282 } 1283 1284 err = ads7846_setup_pendown(spi, ts); 1285 if (err) 1286 goto err_cleanup_filter; 1287 1288 if (pdata->penirq_recheck_delay_usecs) 1289 ts->penirq_recheck_delay_usecs = 1290 pdata->penirq_recheck_delay_usecs; 1291 1292 ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync; 1293 1294 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev)); 1295 snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model); 1296 1297 input_dev->name = ts->name; 1298 input_dev->phys = ts->phys; 1299 input_dev->dev.parent = &spi->dev; 1300 1301 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 1302 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 1303 input_set_abs_params(input_dev, ABS_X, 1304 pdata->x_min ? : 0, 1305 pdata->x_max ? : MAX_12BIT, 1306 0, 0); 1307 input_set_abs_params(input_dev, ABS_Y, 1308 pdata->y_min ? : 0, 1309 pdata->y_max ? : MAX_12BIT, 1310 0, 0); 1311 input_set_abs_params(input_dev, ABS_PRESSURE, 1312 pdata->pressure_min, pdata->pressure_max, 0, 0); 1313 1314 ads7846_setup_spi_msg(ts, pdata); 1315 1316 ts->reg = regulator_get(&spi->dev, "vcc"); 1317 if (IS_ERR(ts->reg)) { 1318 err = PTR_ERR(ts->reg); 1319 dev_err(&spi->dev, "unable to get regulator: %d\n", err); 1320 goto err_free_gpio; 1321 } 1322 1323 err = regulator_enable(ts->reg); 1324 if (err) { 1325 dev_err(&spi->dev, "unable to enable regulator: %d\n", err); 1326 goto err_put_regulator; 1327 } 1328 1329 irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING; 1330 irq_flags |= IRQF_ONESHOT; 1331 1332 err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq, 1333 irq_flags, spi->dev.driver->name, ts); 1334 if (err && !pdata->irq_flags) { 1335 dev_info(&spi->dev, 1336 "trying pin change workaround on irq %d\n", spi->irq); 1337 irq_flags |= IRQF_TRIGGER_RISING; 1338 err = request_threaded_irq(spi->irq, 1339 ads7846_hard_irq, ads7846_irq, 1340 irq_flags, spi->dev.driver->name, ts); 1341 } 1342 1343 if (err) { 1344 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq); 1345 goto err_disable_regulator; 1346 } 1347 1348 err = ads784x_hwmon_register(spi, ts); 1349 if (err) 1350 goto err_free_irq; 1351 1352 dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq); 1353 1354 /* 1355 * Take a first sample, leaving nPENIRQ active and vREF off; avoid 1356 * the touchscreen, in case it's not connected. 1357 */ 1358 if (ts->model == 7845) 1359 ads7845_read12_ser(&spi->dev, PWRDOWN); 1360 else 1361 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux)); 1362 1363 err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group); 1364 if (err) 1365 goto err_remove_hwmon; 1366 1367 err = input_register_device(input_dev); 1368 if (err) 1369 goto err_remove_attr_group; 1370 1371 device_init_wakeup(&spi->dev, pdata->wakeup); 1372 1373 return 0; 1374 1375 err_remove_attr_group: 1376 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1377 err_remove_hwmon: 1378 ads784x_hwmon_unregister(spi, ts); 1379 err_free_irq: 1380 free_irq(spi->irq, ts); 1381 err_disable_regulator: 1382 regulator_disable(ts->reg); 1383 err_put_regulator: 1384 regulator_put(ts->reg); 1385 err_free_gpio: 1386 if (!ts->get_pendown_state) 1387 gpio_free(ts->gpio_pendown); 1388 err_cleanup_filter: 1389 if (ts->filter_cleanup) 1390 ts->filter_cleanup(ts->filter_data); 1391 err_free_mem: 1392 input_free_device(input_dev); 1393 kfree(packet); 1394 kfree(ts); 1395 return err; 1396 } 1397 1398 static int ads7846_remove(struct spi_device *spi) 1399 { 1400 struct ads7846 *ts = dev_get_drvdata(&spi->dev); 1401 1402 device_init_wakeup(&spi->dev, false); 1403 1404 sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group); 1405 1406 ads7846_disable(ts); 1407 free_irq(ts->spi->irq, ts); 1408 1409 input_unregister_device(ts->input); 1410 1411 ads784x_hwmon_unregister(spi, ts); 1412 1413 regulator_disable(ts->reg); 1414 regulator_put(ts->reg); 1415 1416 if (!ts->get_pendown_state) { 1417 /* 1418 * If we are not using specialized pendown method we must 1419 * have been relying on gpio we set up ourselves. 1420 */ 1421 gpio_free(ts->gpio_pendown); 1422 } 1423 1424 if (ts->filter_cleanup) 1425 ts->filter_cleanup(ts->filter_data); 1426 1427 kfree(ts->packet); 1428 kfree(ts); 1429 1430 dev_dbg(&spi->dev, "unregistered touchscreen\n"); 1431 1432 return 0; 1433 } 1434 1435 static struct spi_driver ads7846_driver = { 1436 .driver = { 1437 .name = "ads7846", 1438 .owner = THIS_MODULE, 1439 .pm = &ads7846_pm, 1440 }, 1441 .probe = ads7846_probe, 1442 .remove = ads7846_remove, 1443 }; 1444 1445 module_spi_driver(ads7846_driver); 1446 1447 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver"); 1448 MODULE_LICENSE("GPL"); 1449 MODULE_ALIAS("spi:ads7846"); 1450