1 /* 2 * TSC2004/TSC2005 touchscreen driver core 3 * 4 * Copyright (C) 2006-2010 Nokia Corporation 5 * Copyright (C) 2015 QWERTY Embedded Design 6 * Copyright (C) 2015 EMAC Inc. 7 * 8 * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com> 9 * based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com> 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License as published by 13 * the Free Software Foundation; either version 2 of the License, or 14 * (at your option) any later version. 15 * 16 * This program is distributed in the hope that it will be useful, 17 * but WITHOUT ANY WARRANTY; without even the implied warranty of 18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 * GNU General Public License for more details. 20 */ 21 22 #include <linux/kernel.h> 23 #include <linux/module.h> 24 #include <linux/input.h> 25 #include <linux/input/touchscreen.h> 26 #include <linux/interrupt.h> 27 #include <linux/delay.h> 28 #include <linux/pm.h> 29 #include <linux/of.h> 30 #include <linux/regulator/consumer.h> 31 #include <linux/regmap.h> 32 #include <linux/gpio/consumer.h> 33 #include "tsc200x-core.h" 34 35 /* 36 * The touchscreen interface operates as follows: 37 * 38 * 1) Pen is pressed against the touchscreen. 39 * 2) TSC200X performs AD conversion. 40 * 3) After the conversion is done TSC200X drives DAV line down. 41 * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled. 42 * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2 43 * values. 44 * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up 45 * tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms). 46 * 7) When the penup timer expires, there have not been touch or DAV interrupts 47 * during the last 40ms which means the pen has been lifted. 48 * 49 * ESD recovery via a hardware reset is done if the TSC200X doesn't respond 50 * after a configurable period (in ms) of activity. If esd_timeout is 0, the 51 * watchdog is disabled. 52 */ 53 54 static const struct regmap_range tsc200x_writable_ranges[] = { 55 regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2), 56 }; 57 58 static const struct regmap_access_table tsc200x_writable_table = { 59 .yes_ranges = tsc200x_writable_ranges, 60 .n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges), 61 }; 62 63 const struct regmap_config tsc200x_regmap_config = { 64 .reg_bits = 8, 65 .val_bits = 16, 66 .reg_stride = 0x08, 67 .max_register = 0x78, 68 .read_flag_mask = TSC200X_REG_READ, 69 .write_flag_mask = TSC200X_REG_PND0, 70 .wr_table = &tsc200x_writable_table, 71 .use_single_rw = true, 72 }; 73 EXPORT_SYMBOL_GPL(tsc200x_regmap_config); 74 75 struct tsc200x_data { 76 u16 x; 77 u16 y; 78 u16 z1; 79 u16 z2; 80 } __packed; 81 #define TSC200X_DATA_REGS 4 82 83 struct tsc200x { 84 struct device *dev; 85 struct regmap *regmap; 86 __u16 bustype; 87 88 struct input_dev *idev; 89 char phys[32]; 90 91 struct mutex mutex; 92 93 /* raw copy of previous x,y,z */ 94 int in_x; 95 int in_y; 96 int in_z1; 97 int in_z2; 98 99 spinlock_t lock; 100 struct timer_list penup_timer; 101 102 unsigned int esd_timeout; 103 struct delayed_work esd_work; 104 unsigned long last_valid_interrupt; 105 106 unsigned int x_plate_ohm; 107 108 bool opened; 109 bool suspended; 110 111 bool pen_down; 112 113 struct regulator *vio; 114 115 struct gpio_desc *reset_gpio; 116 int (*tsc200x_cmd)(struct device *dev, u8 cmd); 117 int irq; 118 }; 119 120 static void tsc200x_update_pen_state(struct tsc200x *ts, 121 int x, int y, int pressure) 122 { 123 if (pressure) { 124 input_report_abs(ts->idev, ABS_X, x); 125 input_report_abs(ts->idev, ABS_Y, y); 126 input_report_abs(ts->idev, ABS_PRESSURE, pressure); 127 if (!ts->pen_down) { 128 input_report_key(ts->idev, BTN_TOUCH, !!pressure); 129 ts->pen_down = true; 130 } 131 } else { 132 input_report_abs(ts->idev, ABS_PRESSURE, 0); 133 if (ts->pen_down) { 134 input_report_key(ts->idev, BTN_TOUCH, 0); 135 ts->pen_down = false; 136 } 137 } 138 input_sync(ts->idev); 139 dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y, 140 pressure); 141 } 142 143 static irqreturn_t tsc200x_irq_thread(int irq, void *_ts) 144 { 145 struct tsc200x *ts = _ts; 146 unsigned long flags; 147 unsigned int pressure; 148 struct tsc200x_data tsdata; 149 int error; 150 151 /* read the coordinates */ 152 error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata, 153 TSC200X_DATA_REGS); 154 if (unlikely(error)) 155 goto out; 156 157 /* validate position */ 158 if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT)) 159 goto out; 160 161 /* Skip reading if the pressure components are out of range */ 162 if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT)) 163 goto out; 164 if (unlikely(tsdata.z1 >= tsdata.z2)) 165 goto out; 166 167 /* 168 * Skip point if this is a pen down with the exact same values as 169 * the value before pen-up - that implies SPI fed us stale data 170 */ 171 if (!ts->pen_down && 172 ts->in_x == tsdata.x && ts->in_y == tsdata.y && 173 ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) { 174 goto out; 175 } 176 177 /* 178 * At this point we are happy we have a valid and useful reading. 179 * Remember it for later comparisons. We may now begin downsampling. 180 */ 181 ts->in_x = tsdata.x; 182 ts->in_y = tsdata.y; 183 ts->in_z1 = tsdata.z1; 184 ts->in_z2 = tsdata.z2; 185 186 /* Compute touch pressure resistance using equation #1 */ 187 pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1; 188 pressure = pressure * ts->x_plate_ohm / 4096; 189 if (unlikely(pressure > MAX_12BIT)) 190 goto out; 191 192 spin_lock_irqsave(&ts->lock, flags); 193 194 tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure); 195 mod_timer(&ts->penup_timer, 196 jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS)); 197 198 spin_unlock_irqrestore(&ts->lock, flags); 199 200 ts->last_valid_interrupt = jiffies; 201 out: 202 return IRQ_HANDLED; 203 } 204 205 static void tsc200x_penup_timer(unsigned long data) 206 { 207 struct tsc200x *ts = (struct tsc200x *)data; 208 unsigned long flags; 209 210 spin_lock_irqsave(&ts->lock, flags); 211 tsc200x_update_pen_state(ts, 0, 0, 0); 212 spin_unlock_irqrestore(&ts->lock, flags); 213 } 214 215 static void tsc200x_start_scan(struct tsc200x *ts) 216 { 217 regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE); 218 regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE); 219 regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE); 220 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL); 221 } 222 223 static void tsc200x_stop_scan(struct tsc200x *ts) 224 { 225 ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP); 226 } 227 228 static void tsc200x_reset(struct tsc200x *ts) 229 { 230 if (ts->reset_gpio) { 231 gpiod_set_value_cansleep(ts->reset_gpio, 1); 232 usleep_range(100, 500); /* only 10us required */ 233 gpiod_set_value_cansleep(ts->reset_gpio, 0); 234 } 235 } 236 237 /* must be called with ts->mutex held */ 238 static void __tsc200x_disable(struct tsc200x *ts) 239 { 240 tsc200x_stop_scan(ts); 241 242 disable_irq(ts->irq); 243 del_timer_sync(&ts->penup_timer); 244 245 cancel_delayed_work_sync(&ts->esd_work); 246 247 enable_irq(ts->irq); 248 } 249 250 /* must be called with ts->mutex held */ 251 static void __tsc200x_enable(struct tsc200x *ts) 252 { 253 tsc200x_start_scan(ts); 254 255 if (ts->esd_timeout && ts->reset_gpio) { 256 ts->last_valid_interrupt = jiffies; 257 schedule_delayed_work(&ts->esd_work, 258 round_jiffies_relative( 259 msecs_to_jiffies(ts->esd_timeout))); 260 } 261 } 262 263 static ssize_t tsc200x_selftest_show(struct device *dev, 264 struct device_attribute *attr, 265 char *buf) 266 { 267 struct tsc200x *ts = dev_get_drvdata(dev); 268 unsigned int temp_high; 269 unsigned int temp_high_orig; 270 unsigned int temp_high_test; 271 bool success = true; 272 int error; 273 274 mutex_lock(&ts->mutex); 275 276 /* 277 * Test TSC200X communications via temp high register. 278 */ 279 __tsc200x_disable(ts); 280 281 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig); 282 if (error) { 283 dev_warn(dev, "selftest failed: read error %d\n", error); 284 success = false; 285 goto out; 286 } 287 288 temp_high_test = (temp_high_orig - 1) & MAX_12BIT; 289 290 error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test); 291 if (error) { 292 dev_warn(dev, "selftest failed: write error %d\n", error); 293 success = false; 294 goto out; 295 } 296 297 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high); 298 if (error) { 299 dev_warn(dev, "selftest failed: read error %d after write\n", 300 error); 301 success = false; 302 goto out; 303 } 304 305 if (temp_high != temp_high_test) { 306 dev_warn(dev, "selftest failed: %d != %d\n", 307 temp_high, temp_high_test); 308 success = false; 309 } 310 311 /* hardware reset */ 312 tsc200x_reset(ts); 313 314 if (!success) 315 goto out; 316 317 /* test that the reset really happened */ 318 error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high); 319 if (error) { 320 dev_warn(dev, "selftest failed: read error %d after reset\n", 321 error); 322 success = false; 323 goto out; 324 } 325 326 if (temp_high != temp_high_orig) { 327 dev_warn(dev, "selftest failed after reset: %d != %d\n", 328 temp_high, temp_high_orig); 329 success = false; 330 } 331 332 out: 333 __tsc200x_enable(ts); 334 mutex_unlock(&ts->mutex); 335 336 return sprintf(buf, "%d\n", success); 337 } 338 339 static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL); 340 341 static struct attribute *tsc200x_attrs[] = { 342 &dev_attr_selftest.attr, 343 NULL 344 }; 345 346 static umode_t tsc200x_attr_is_visible(struct kobject *kobj, 347 struct attribute *attr, int n) 348 { 349 struct device *dev = container_of(kobj, struct device, kobj); 350 struct tsc200x *ts = dev_get_drvdata(dev); 351 umode_t mode = attr->mode; 352 353 if (attr == &dev_attr_selftest.attr) { 354 if (!ts->reset_gpio) 355 mode = 0; 356 } 357 358 return mode; 359 } 360 361 static const struct attribute_group tsc200x_attr_group = { 362 .is_visible = tsc200x_attr_is_visible, 363 .attrs = tsc200x_attrs, 364 }; 365 366 static void tsc200x_esd_work(struct work_struct *work) 367 { 368 struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work); 369 int error; 370 unsigned int r; 371 372 if (!mutex_trylock(&ts->mutex)) { 373 /* 374 * If the mutex is taken, it means that disable or enable is in 375 * progress. In that case just reschedule the work. If the work 376 * is not needed, it will be canceled by disable. 377 */ 378 goto reschedule; 379 } 380 381 if (time_is_after_jiffies(ts->last_valid_interrupt + 382 msecs_to_jiffies(ts->esd_timeout))) 383 goto out; 384 385 /* We should be able to read register without disabling interrupts. */ 386 error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r); 387 if (!error && 388 !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) { 389 goto out; 390 } 391 392 /* 393 * If we could not read our known value from configuration register 0 394 * then we should reset the controller as if from power-up and start 395 * scanning again. 396 */ 397 dev_info(ts->dev, "TSC200X not responding - resetting\n"); 398 399 disable_irq(ts->irq); 400 del_timer_sync(&ts->penup_timer); 401 402 tsc200x_update_pen_state(ts, 0, 0, 0); 403 404 tsc200x_reset(ts); 405 406 enable_irq(ts->irq); 407 tsc200x_start_scan(ts); 408 409 out: 410 mutex_unlock(&ts->mutex); 411 reschedule: 412 /* re-arm the watchdog */ 413 schedule_delayed_work(&ts->esd_work, 414 round_jiffies_relative( 415 msecs_to_jiffies(ts->esd_timeout))); 416 } 417 418 static int tsc200x_open(struct input_dev *input) 419 { 420 struct tsc200x *ts = input_get_drvdata(input); 421 422 mutex_lock(&ts->mutex); 423 424 if (!ts->suspended) 425 __tsc200x_enable(ts); 426 427 ts->opened = true; 428 429 mutex_unlock(&ts->mutex); 430 431 return 0; 432 } 433 434 static void tsc200x_close(struct input_dev *input) 435 { 436 struct tsc200x *ts = input_get_drvdata(input); 437 438 mutex_lock(&ts->mutex); 439 440 if (!ts->suspended) 441 __tsc200x_disable(ts); 442 443 ts->opened = false; 444 445 mutex_unlock(&ts->mutex); 446 } 447 448 int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id, 449 struct regmap *regmap, 450 int (*tsc200x_cmd)(struct device *dev, u8 cmd)) 451 { 452 struct tsc200x *ts; 453 struct input_dev *input_dev; 454 u32 x_plate_ohm; 455 u32 esd_timeout; 456 int error; 457 458 if (irq <= 0) { 459 dev_err(dev, "no irq\n"); 460 return -ENODEV; 461 } 462 463 if (IS_ERR(regmap)) 464 return PTR_ERR(regmap); 465 466 if (!tsc200x_cmd) { 467 dev_err(dev, "no cmd function\n"); 468 return -ENODEV; 469 } 470 471 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL); 472 if (!ts) 473 return -ENOMEM; 474 475 input_dev = devm_input_allocate_device(dev); 476 if (!input_dev) 477 return -ENOMEM; 478 479 ts->irq = irq; 480 ts->dev = dev; 481 ts->idev = input_dev; 482 ts->regmap = regmap; 483 ts->tsc200x_cmd = tsc200x_cmd; 484 485 error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm); 486 ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm; 487 488 error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms", 489 &esd_timeout); 490 ts->esd_timeout = error ? 0 : esd_timeout; 491 492 ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); 493 if (IS_ERR(ts->reset_gpio)) { 494 error = PTR_ERR(ts->reset_gpio); 495 dev_err(dev, "error acquiring reset gpio: %d\n", error); 496 return error; 497 } 498 499 ts->vio = devm_regulator_get(dev, "vio"); 500 if (IS_ERR(ts->vio)) { 501 error = PTR_ERR(ts->vio); 502 dev_err(dev, "error acquiring vio regulator: %d", error); 503 return error; 504 } 505 506 mutex_init(&ts->mutex); 507 508 spin_lock_init(&ts->lock); 509 setup_timer(&ts->penup_timer, tsc200x_penup_timer, (unsigned long)ts); 510 511 INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work); 512 513 snprintf(ts->phys, sizeof(ts->phys), 514 "%s/input-ts", dev_name(dev)); 515 516 if (tsc_id->product == 2004) { 517 input_dev->name = "TSC200X touchscreen"; 518 } else { 519 input_dev->name = devm_kasprintf(dev, GFP_KERNEL, 520 "TSC%04d touchscreen", 521 tsc_id->product); 522 if (!input_dev->name) 523 return -ENOMEM; 524 } 525 526 input_dev->phys = ts->phys; 527 input_dev->id = *tsc_id; 528 529 input_dev->open = tsc200x_open; 530 input_dev->close = tsc200x_close; 531 532 input_set_drvdata(input_dev, ts); 533 534 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 535 536 input_set_abs_params(input_dev, ABS_X, 537 0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0); 538 input_set_abs_params(input_dev, ABS_Y, 539 0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0); 540 input_set_abs_params(input_dev, ABS_PRESSURE, 541 0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0); 542 543 touchscreen_parse_properties(input_dev, false, NULL); 544 545 /* Ensure the touchscreen is off */ 546 tsc200x_stop_scan(ts); 547 548 error = devm_request_threaded_irq(dev, irq, NULL, 549 tsc200x_irq_thread, 550 IRQF_TRIGGER_RISING | IRQF_ONESHOT, 551 "tsc200x", ts); 552 if (error) { 553 dev_err(dev, "Failed to request irq, err: %d\n", error); 554 return error; 555 } 556 557 error = regulator_enable(ts->vio); 558 if (error) 559 return error; 560 561 dev_set_drvdata(dev, ts); 562 error = sysfs_create_group(&dev->kobj, &tsc200x_attr_group); 563 if (error) { 564 dev_err(dev, 565 "Failed to create sysfs attributes, err: %d\n", error); 566 goto disable_regulator; 567 } 568 569 error = input_register_device(ts->idev); 570 if (error) { 571 dev_err(dev, 572 "Failed to register input device, err: %d\n", error); 573 goto err_remove_sysfs; 574 } 575 576 irq_set_irq_wake(irq, 1); 577 return 0; 578 579 err_remove_sysfs: 580 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group); 581 disable_regulator: 582 regulator_disable(ts->vio); 583 return error; 584 } 585 EXPORT_SYMBOL_GPL(tsc200x_probe); 586 587 int tsc200x_remove(struct device *dev) 588 { 589 struct tsc200x *ts = dev_get_drvdata(dev); 590 591 sysfs_remove_group(&dev->kobj, &tsc200x_attr_group); 592 593 regulator_disable(ts->vio); 594 595 return 0; 596 } 597 EXPORT_SYMBOL_GPL(tsc200x_remove); 598 599 static int __maybe_unused tsc200x_suspend(struct device *dev) 600 { 601 struct tsc200x *ts = dev_get_drvdata(dev); 602 603 mutex_lock(&ts->mutex); 604 605 if (!ts->suspended && ts->opened) 606 __tsc200x_disable(ts); 607 608 ts->suspended = true; 609 610 mutex_unlock(&ts->mutex); 611 612 return 0; 613 } 614 615 static int __maybe_unused tsc200x_resume(struct device *dev) 616 { 617 struct tsc200x *ts = dev_get_drvdata(dev); 618 619 mutex_lock(&ts->mutex); 620 621 if (ts->suspended && ts->opened) 622 __tsc200x_enable(ts); 623 624 ts->suspended = false; 625 626 mutex_unlock(&ts->mutex); 627 628 return 0; 629 } 630 631 SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume); 632 EXPORT_SYMBOL_GPL(tsc200x_pm_ops); 633 634 MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>"); 635 MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core"); 636 MODULE_LICENSE("GPL"); 637