drivers/input/touchscreen/tsc200x-core.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * TSC2004/TSC2005 touchscreen driver core
   4  *
   5  * Copyright (C) 2006-2010 Nokia Corporation
   6  * Copyright (C) 2015 QWERTY Embedded Design
   7  * Copyright (C) 2015 EMAC Inc.
   8  *
   9  * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com>
  10  * based on TSC2301 driver by Klaus K. Pedersen <klaus.k.pedersen@nokia.com>
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/input.h>
  16 #include <linux/input/touchscreen.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/delay.h>
  19 #include <linux/pm.h>
  20 #include <linux/of.h>
  21 #include <linux/regulator/consumer.h>
  22 #include <linux/regmap.h>
  23 #include <linux/gpio/consumer.h>
  24 #include "tsc200x-core.h"
  25
  26 /*
  27  * The touchscreen interface operates as follows:
  28  *
  29  * 1) Pen is pressed against the touchscreen.
  30  * 2) TSC200X performs AD conversion.
  31  * 3) After the conversion is done TSC200X drives DAV line down.
  32  * 4) GPIO IRQ is received and tsc200x_irq_thread() is scheduled.
  33  * 5) tsc200x_irq_thread() queues up a transfer to fetch the x, y, z1, z2
  34  *    values.
  35  * 6) tsc200x_irq_thread() reports coordinates to input layer and sets up
  36  *    tsc200x_penup_timer() to be called after TSC200X_PENUP_TIME_MS (40ms).
  37  * 7) When the penup timer expires, there have not been touch or DAV interrupts
  38  *    during the last 40ms which means the pen has been lifted.
  39  *
  40  * ESD recovery via a hardware reset is done if the TSC200X doesn't respond
  41  * after a configurable period (in ms) of activity. If esd_timeout is 0, the
  42  * watchdog is disabled.
  43  */
  44
  45 static const struct regmap_range tsc200x_writable_ranges[] = {
  46         regmap_reg_range(TSC200X_REG_AUX_HIGH, TSC200X_REG_CFR2),
  47 };
  48
  49 static const struct regmap_access_table tsc200x_writable_table = {
  50         .yes_ranges = tsc200x_writable_ranges,
  51         .n_yes_ranges = ARRAY_SIZE(tsc200x_writable_ranges),
  52 };
  53
  54 const struct regmap_config tsc200x_regmap_config = {
  55         .reg_bits = 8,
  56         .val_bits = 16,
  57         .reg_stride = 0x08,
  58         .max_register = 0x78,
  59         .read_flag_mask = TSC200X_REG_READ,
  60         .write_flag_mask = TSC200X_REG_PND0,
  61         .wr_table = &tsc200x_writable_table,
  62         .use_single_read = true,
  63         .use_single_write = true,
  64 };
  65 EXPORT_SYMBOL_GPL(tsc200x_regmap_config);
  66
  67 struct tsc200x_data {
  68         u16 x;
  69         u16 y;
  70         u16 z1;
  71         u16 z2;
  72 } __packed;
  73 #define TSC200X_DATA_REGS 4
  74
  75 struct tsc200x {
  76         struct device           *dev;
  77         struct regmap           *regmap;
  78         __u16                   bustype;
  79
  80         struct input_dev        *idev;
  81         char                    phys[32];
  82
  83         struct mutex            mutex;
  84
  85         /* raw copy of previous x,y,z */
  86         int                     in_x;
  87         int                     in_y;
  88         int                     in_z1;
  89         int                     in_z2;
  90
  91         spinlock_t              lock;
  92         struct timer_list       penup_timer;
  93
  94         unsigned int            esd_timeout;
  95         struct delayed_work     esd_work;
  96         unsigned long           last_valid_interrupt;
  97
  98         unsigned int            x_plate_ohm;
  99
 100         bool                    opened;
 101         bool                    suspended;
 102
 103         bool                    pen_down;
 104
 105         struct regulator        *vio;
 106
 107         struct gpio_desc        *reset_gpio;
 108         int                     (*tsc200x_cmd)(struct device *dev, u8 cmd);
 109         int                     irq;
 110 };
 111
 112 static void tsc200x_update_pen_state(struct tsc200x *ts,
 113                                      int x, int y, int pressure)
 114 {
 115         if (pressure) {
 116                 input_report_abs(ts->idev, ABS_X, x);
 117                 input_report_abs(ts->idev, ABS_Y, y);
 118                 input_report_abs(ts->idev, ABS_PRESSURE, pressure);
 119                 if (!ts->pen_down) {
 120                         input_report_key(ts->idev, BTN_TOUCH, !!pressure);
 121                         ts->pen_down = true;
 122                 }
 123         } else {
 124                 input_report_abs(ts->idev, ABS_PRESSURE, 0);
 125                 if (ts->pen_down) {
 126                         input_report_key(ts->idev, BTN_TOUCH, 0);
 127                         ts->pen_down = false;
 128                 }
 129         }
 130         input_sync(ts->idev);
 131         dev_dbg(ts->dev, "point(%4d,%4d), pressure (%4d)\n", x, y,
 132                 pressure);
 133 }
 134
 135 static irqreturn_t tsc200x_irq_thread(int irq, void *_ts)
 136 {
 137         struct tsc200x *ts = _ts;
 138         unsigned long flags;
 139         unsigned int pressure;
 140         struct tsc200x_data tsdata;
 141         int error;
 142
 143         /* read the coordinates */
 144         error = regmap_bulk_read(ts->regmap, TSC200X_REG_X, &tsdata,
 145                                  TSC200X_DATA_REGS);
 146         if (unlikely(error))
 147                 goto out;
 148
 149         /* validate position */
 150         if (unlikely(tsdata.x > MAX_12BIT || tsdata.y > MAX_12BIT))
 151                 goto out;
 152
 153         /* Skip reading if the pressure components are out of range */
 154         if (unlikely(tsdata.z1 == 0 || tsdata.z2 > MAX_12BIT))
 155                 goto out;
 156         if (unlikely(tsdata.z1 >= tsdata.z2))
 157                 goto out;
 158
 159        /*
 160         * Skip point if this is a pen down with the exact same values as
 161         * the value before pen-up - that implies SPI fed us stale data
 162         */
 163         if (!ts->pen_down &&
 164             ts->in_x == tsdata.x && ts->in_y == tsdata.y &&
 165             ts->in_z1 == tsdata.z1 && ts->in_z2 == tsdata.z2) {
 166                 goto out;
 167         }
 168
 169         /*
 170          * At this point we are happy we have a valid and useful reading.
 171          * Remember it for later comparisons. We may now begin downsampling.
 172          */
 173         ts->in_x = tsdata.x;
 174         ts->in_y = tsdata.y;
 175         ts->in_z1 = tsdata.z1;
 176         ts->in_z2 = tsdata.z2;
 177
 178         /* Compute touch pressure resistance using equation #1 */
 179         pressure = tsdata.x * (tsdata.z2 - tsdata.z1) / tsdata.z1;
 180         pressure = pressure * ts->x_plate_ohm / 4096;
 181         if (unlikely(pressure > MAX_12BIT))
 182                 goto out;
 183
 184         spin_lock_irqsave(&ts->lock, flags);
 185
 186         tsc200x_update_pen_state(ts, tsdata.x, tsdata.y, pressure);
 187         mod_timer(&ts->penup_timer,
 188                   jiffies + msecs_to_jiffies(TSC200X_PENUP_TIME_MS));
 189
 190         spin_unlock_irqrestore(&ts->lock, flags);
 191
 192         ts->last_valid_interrupt = jiffies;
 193 out:
 194         return IRQ_HANDLED;
 195 }
 196
 197 static void tsc200x_penup_timer(struct timer_list *t)
 198 {
 199         struct tsc200x *ts = from_timer(ts, t, penup_timer);
 200         unsigned long flags;
 201
 202         spin_lock_irqsave(&ts->lock, flags);
 203         tsc200x_update_pen_state(ts, 0, 0, 0);
 204         spin_unlock_irqrestore(&ts->lock, flags);
 205 }
 206
 207 static void tsc200x_start_scan(struct tsc200x *ts)
 208 {
 209         regmap_write(ts->regmap, TSC200X_REG_CFR0, TSC200X_CFR0_INITVALUE);
 210         regmap_write(ts->regmap, TSC200X_REG_CFR1, TSC200X_CFR1_INITVALUE);
 211         regmap_write(ts->regmap, TSC200X_REG_CFR2, TSC200X_CFR2_INITVALUE);
 212         ts->tsc200x_cmd(ts->dev, TSC200X_CMD_NORMAL);
 213 }
 214
 215 static void tsc200x_stop_scan(struct tsc200x *ts)
 216 {
 217         ts->tsc200x_cmd(ts->dev, TSC200X_CMD_STOP);
 218 }
 219
 220 static void tsc200x_reset(struct tsc200x *ts)
 221 {
 222         if (ts->reset_gpio) {
 223                 gpiod_set_value_cansleep(ts->reset_gpio, 1);
 224                 usleep_range(100, 500); /* only 10us required */
 225                 gpiod_set_value_cansleep(ts->reset_gpio, 0);
 226         }
 227 }
 228
 229 /* must be called with ts->mutex held */
 230 static void __tsc200x_disable(struct tsc200x *ts)
 231 {
 232         tsc200x_stop_scan(ts);
 233
 234         disable_irq(ts->irq);
 235         del_timer_sync(&ts->penup_timer);
 236
 237         cancel_delayed_work_sync(&ts->esd_work);
 238
 239         enable_irq(ts->irq);
 240 }
 241
 242 /* must be called with ts->mutex held */
 243 static void __tsc200x_enable(struct tsc200x *ts)
 244 {
 245         tsc200x_start_scan(ts);
 246
 247         if (ts->esd_timeout && ts->reset_gpio) {
 248                 ts->last_valid_interrupt = jiffies;
 249                 schedule_delayed_work(&ts->esd_work,
 250                                 round_jiffies_relative(
 251                                         msecs_to_jiffies(ts->esd_timeout)));
 252         }
 253 }
 254
 255 static ssize_t tsc200x_selftest_show(struct device *dev,
 256                                      struct device_attribute *attr,
 257                                      char *buf)
 258 {
 259         struct tsc200x *ts = dev_get_drvdata(dev);
 260         unsigned int temp_high;
 261         unsigned int temp_high_orig;
 262         unsigned int temp_high_test;
 263         bool success = true;
 264         int error;
 265
 266         mutex_lock(&ts->mutex);
 267
 268         /*
 269          * Test TSC200X communications via temp high register.
 270          */
 271         __tsc200x_disable(ts);
 272
 273         error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high_orig);
 274         if (error) {
 275                 dev_warn(dev, "selftest failed: read error %d\n", error);
 276                 success = false;
 277                 goto out;
 278         }
 279
 280         temp_high_test = (temp_high_orig - 1) & MAX_12BIT;
 281
 282         error = regmap_write(ts->regmap, TSC200X_REG_TEMP_HIGH, temp_high_test);
 283         if (error) {
 284                 dev_warn(dev, "selftest failed: write error %d\n", error);
 285                 success = false;
 286                 goto out;
 287         }
 288
 289         error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
 290         if (error) {
 291                 dev_warn(dev, "selftest failed: read error %d after write\n",
 292                          error);
 293                 success = false;
 294                 goto out;
 295         }
 296
 297         if (temp_high != temp_high_test) {
 298                 dev_warn(dev, "selftest failed: %d != %d\n",
 299                          temp_high, temp_high_test);
 300                 success = false;
 301         }
 302
 303         /* hardware reset */
 304         tsc200x_reset(ts);
 305
 306         if (!success)
 307                 goto out;
 308
 309         /* test that the reset really happened */
 310         error = regmap_read(ts->regmap, TSC200X_REG_TEMP_HIGH, &temp_high);
 311         if (error) {
 312                 dev_warn(dev, "selftest failed: read error %d after reset\n",
 313                          error);
 314                 success = false;
 315                 goto out;
 316         }
 317
 318         if (temp_high != temp_high_orig) {
 319                 dev_warn(dev, "selftest failed after reset: %d != %d\n",
 320                          temp_high, temp_high_orig);
 321                 success = false;
 322         }
 323
 324 out:
 325         __tsc200x_enable(ts);
 326         mutex_unlock(&ts->mutex);
 327
 328         return sprintf(buf, "%d\n", success);
 329 }
 330
 331 static DEVICE_ATTR(selftest, S_IRUGO, tsc200x_selftest_show, NULL);
 332
 333 static struct attribute *tsc200x_attrs[] = {
 334         &dev_attr_selftest.attr,
 335         NULL
 336 };
 337
 338 static umode_t tsc200x_attr_is_visible(struct kobject *kobj,
 339                                       struct attribute *attr, int n)
 340 {
 341         struct device *dev = container_of(kobj, struct device, kobj);
 342         struct tsc200x *ts = dev_get_drvdata(dev);
 343         umode_t mode = attr->mode;
 344
 345         if (attr == &dev_attr_selftest.attr) {
 346                 if (!ts->reset_gpio)
 347                         mode = 0;
 348         }
 349
 350         return mode;
 351 }
 352
 353 static const struct attribute_group tsc200x_attr_group = {
 354         .is_visible     = tsc200x_attr_is_visible,
 355         .attrs          = tsc200x_attrs,
 356 };
 357
 358 static void tsc200x_esd_work(struct work_struct *work)
 359 {
 360         struct tsc200x *ts = container_of(work, struct tsc200x, esd_work.work);
 361         int error;
 362         unsigned int r;
 363
 364         if (!mutex_trylock(&ts->mutex)) {
 365                 /*
 366                  * If the mutex is taken, it means that disable or enable is in
 367                  * progress. In that case just reschedule the work. If the work
 368                  * is not needed, it will be canceled by disable.
 369                  */
 370                 goto reschedule;
 371         }
 372
 373         if (time_is_after_jiffies(ts->last_valid_interrupt +
 374                                   msecs_to_jiffies(ts->esd_timeout)))
 375                 goto out;
 376
 377         /* We should be able to read register without disabling interrupts. */
 378         error = regmap_read(ts->regmap, TSC200X_REG_CFR0, &r);
 379         if (!error &&
 380             !((r ^ TSC200X_CFR0_INITVALUE) & TSC200X_CFR0_RW_MASK)) {
 381                 goto out;
 382         }
 383
 384         /*
 385          * If we could not read our known value from configuration register 0
 386          * then we should reset the controller as if from power-up and start
 387          * scanning again.
 388          */
 389         dev_info(ts->dev, "TSC200X not responding - resetting\n");
 390
 391         disable_irq(ts->irq);
 392         del_timer_sync(&ts->penup_timer);
 393
 394         tsc200x_update_pen_state(ts, 0, 0, 0);
 395
 396         tsc200x_reset(ts);
 397
 398         enable_irq(ts->irq);
 399         tsc200x_start_scan(ts);
 400
 401 out:
 402         mutex_unlock(&ts->mutex);
 403 reschedule:
 404         /* re-arm the watchdog */
 405         schedule_delayed_work(&ts->esd_work,
 406                               round_jiffies_relative(
 407                                         msecs_to_jiffies(ts->esd_timeout)));
 408 }
 409
 410 static int tsc200x_open(struct input_dev *input)
 411 {
 412         struct tsc200x *ts = input_get_drvdata(input);
 413
 414         mutex_lock(&ts->mutex);
 415
 416         if (!ts->suspended)
 417                 __tsc200x_enable(ts);
 418
 419         ts->opened = true;
 420
 421         mutex_unlock(&ts->mutex);
 422
 423         return 0;
 424 }
 425
 426 static void tsc200x_close(struct input_dev *input)
 427 {
 428         struct tsc200x *ts = input_get_drvdata(input);
 429
 430         mutex_lock(&ts->mutex);
 431
 432         if (!ts->suspended)
 433                 __tsc200x_disable(ts);
 434
 435         ts->opened = false;
 436
 437         mutex_unlock(&ts->mutex);
 438 }
 439
 440 int tsc200x_probe(struct device *dev, int irq, const struct input_id *tsc_id,
 441                   struct regmap *regmap,
 442                   int (*tsc200x_cmd)(struct device *dev, u8 cmd))
 443 {
 444         struct tsc200x *ts;
 445         struct input_dev *input_dev;
 446         u32 x_plate_ohm;
 447         u32 esd_timeout;
 448         int error;
 449
 450         if (irq <= 0) {
 451                 dev_err(dev, "no irq\n");
 452                 return -ENODEV;
 453         }
 454
 455         if (IS_ERR(regmap))
 456                 return PTR_ERR(regmap);
 457
 458         if (!tsc200x_cmd) {
 459                 dev_err(dev, "no cmd function\n");
 460                 return -ENODEV;
 461         }
 462
 463         ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 464         if (!ts)
 465                 return -ENOMEM;
 466
 467         input_dev = devm_input_allocate_device(dev);
 468         if (!input_dev)
 469                 return -ENOMEM;
 470
 471         ts->irq = irq;
 472         ts->dev = dev;
 473         ts->idev = input_dev;
 474         ts->regmap = regmap;
 475         ts->tsc200x_cmd = tsc200x_cmd;
 476
 477         error = device_property_read_u32(dev, "ti,x-plate-ohms", &x_plate_ohm);
 478         ts->x_plate_ohm = error ? TSC200X_DEF_RESISTOR : x_plate_ohm;
 479
 480         error = device_property_read_u32(dev, "ti,esd-recovery-timeout-ms",
 481                                          &esd_timeout);
 482         ts->esd_timeout = error ? 0 : esd_timeout;
 483
 484         ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
 485         if (IS_ERR(ts->reset_gpio)) {
 486                 error = PTR_ERR(ts->reset_gpio);
 487                 dev_err(dev, "error acquiring reset gpio: %d\n", error);
 488                 return error;
 489         }
 490
 491         ts->vio = devm_regulator_get(dev, "vio");
 492         if (IS_ERR(ts->vio)) {
 493                 error = PTR_ERR(ts->vio);
 494                 dev_err(dev, "error acquiring vio regulator: %d", error);
 495                 return error;
 496         }
 497
 498         mutex_init(&ts->mutex);
 499
 500         spin_lock_init(&ts->lock);
 501         timer_setup(&ts->penup_timer, tsc200x_penup_timer, 0);
 502
 503         INIT_DELAYED_WORK(&ts->esd_work, tsc200x_esd_work);
 504
 505         snprintf(ts->phys, sizeof(ts->phys),
 506                  "%s/input-ts", dev_name(dev));
 507
 508         if (tsc_id->product == 2004) {
 509                 input_dev->name = "TSC200X touchscreen";
 510         } else {
 511                 input_dev->name = devm_kasprintf(dev, GFP_KERNEL,
 512                                                  "TSC%04d touchscreen",
 513                                                  tsc_id->product);
 514                 if (!input_dev->name)
 515                         return -ENOMEM;
 516         }
 517
 518         input_dev->phys = ts->phys;
 519         input_dev->id = *tsc_id;
 520
 521         input_dev->open = tsc200x_open;
 522         input_dev->close = tsc200x_close;
 523
 524         input_set_drvdata(input_dev, ts);
 525
 526         __set_bit(INPUT_PROP_DIRECT, input_dev->propbit);
 527         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 528
 529         input_set_abs_params(input_dev, ABS_X,
 530                              0, MAX_12BIT, TSC200X_DEF_X_FUZZ, 0);
 531         input_set_abs_params(input_dev, ABS_Y,
 532                              0, MAX_12BIT, TSC200X_DEF_Y_FUZZ, 0);
 533         input_set_abs_params(input_dev, ABS_PRESSURE,
 534                              0, MAX_12BIT, TSC200X_DEF_P_FUZZ, 0);
 535
 536         touchscreen_parse_properties(input_dev, false, NULL);
 537
 538         /* Ensure the touchscreen is off */
 539         tsc200x_stop_scan(ts);
 540
 541         error = devm_request_threaded_irq(dev, irq, NULL,
 542                                           tsc200x_irq_thread,
 543                                           IRQF_TRIGGER_RISING | IRQF_ONESHOT,
 544                                           "tsc200x", ts);
 545         if (error) {
 546                 dev_err(dev, "Failed to request irq, err: %d\n", error);
 547                 return error;
 548         }
 549
 550         error = regulator_enable(ts->vio);
 551         if (error)
 552                 return error;
 553
 554         dev_set_drvdata(dev, ts);
 555         error = sysfs_create_group(&dev->kobj, &tsc200x_attr_group);
 556         if (error) {
 557                 dev_err(dev,
 558                         "Failed to create sysfs attributes, err: %d\n", error);
 559                 goto disable_regulator;
 560         }
 561
 562         error = input_register_device(ts->idev);
 563         if (error) {
 564                 dev_err(dev,
 565                         "Failed to register input device, err: %d\n", error);
 566                 goto err_remove_sysfs;
 567         }
 568
 569         irq_set_irq_wake(irq, 1);
 570         return 0;
 571
 572 err_remove_sysfs:
 573         sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
 574 disable_regulator:
 575         regulator_disable(ts->vio);
 576         return error;
 577 }
 578 EXPORT_SYMBOL_GPL(tsc200x_probe);
 579
 580 int tsc200x_remove(struct device *dev)
 581 {
 582         struct tsc200x *ts = dev_get_drvdata(dev);
 583
 584         sysfs_remove_group(&dev->kobj, &tsc200x_attr_group);
 585
 586         regulator_disable(ts->vio);
 587
 588         return 0;
 589 }
 590 EXPORT_SYMBOL_GPL(tsc200x_remove);
 591
 592 static int __maybe_unused tsc200x_suspend(struct device *dev)
 593 {
 594         struct tsc200x *ts = dev_get_drvdata(dev);
 595
 596         mutex_lock(&ts->mutex);
 597
 598         if (!ts->suspended && ts->opened)
 599                 __tsc200x_disable(ts);
 600
 601         ts->suspended = true;
 602
 603         mutex_unlock(&ts->mutex);
 604
 605         return 0;
 606 }
 607
 608 static int __maybe_unused tsc200x_resume(struct device *dev)
 609 {
 610         struct tsc200x *ts = dev_get_drvdata(dev);
 611
 612         mutex_lock(&ts->mutex);
 613
 614         if (ts->suspended && ts->opened)
 615                 __tsc200x_enable(ts);
 616
 617         ts->suspended = false;
 618
 619         mutex_unlock(&ts->mutex);
 620
 621         return 0;
 622 }
 623
 624 SIMPLE_DEV_PM_OPS(tsc200x_pm_ops, tsc200x_suspend, tsc200x_resume);
 625 EXPORT_SYMBOL_GPL(tsc200x_pm_ops);
 626
 627 MODULE_AUTHOR("Lauri Leukkunen <lauri.leukkunen@nokia.com>");
 628 MODULE_DESCRIPTION("TSC200x Touchscreen Driver Core");
 629 MODULE_LICENSE("GPL");