1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * AD7879/AD7889 based touchscreen and GPIO driver 4 * 5 * Copyright (C) 2008-2010 Michael Hennerich, Analog Devices Inc. 6 * 7 * History: 8 * Copyright (c) 2005 David Brownell 9 * Copyright (c) 2006 Nokia Corporation 10 * Various changes: Imre Deak <imre.deak@nokia.com> 11 * 12 * Using code from: 13 * - corgi_ts.c 14 * Copyright (C) 2004-2005 Richard Purdie 15 * - omap_ts.[hc], ads7846.h, ts_osk.c 16 * Copyright (C) 2002 MontaVista Software 17 * Copyright (C) 2004 Texas Instruments 18 * Copyright (C) 2005 Dirk Behme 19 * - ad7877.c 20 * Copyright (C) 2006-2008 Analog Devices Inc. 21 */ 22 23 #include <linux/device.h> 24 #include <linux/delay.h> 25 #include <linux/input.h> 26 #include <linux/interrupt.h> 27 #include <linux/irq.h> 28 #include <linux/property.h> 29 #include <linux/regmap.h> 30 #include <linux/slab.h> 31 #include <linux/gpio/driver.h> 32 33 #include <linux/input/touchscreen.h> 34 #include <linux/module.h> 35 #include "ad7879.h" 36 37 #define AD7879_REG_ZEROS 0 38 #define AD7879_REG_CTRL1 1 39 #define AD7879_REG_CTRL2 2 40 #define AD7879_REG_CTRL3 3 41 #define AD7879_REG_AUX1HIGH 4 42 #define AD7879_REG_AUX1LOW 5 43 #define AD7879_REG_TEMP1HIGH 6 44 #define AD7879_REG_TEMP1LOW 7 45 #define AD7879_REG_XPLUS 8 46 #define AD7879_REG_YPLUS 9 47 #define AD7879_REG_Z1 10 48 #define AD7879_REG_Z2 11 49 #define AD7879_REG_AUXVBAT 12 50 #define AD7879_REG_TEMP 13 51 #define AD7879_REG_REVID 14 52 53 /* Control REG 1 */ 54 #define AD7879_TMR(x) ((x & 0xFF) << 0) 55 #define AD7879_ACQ(x) ((x & 0x3) << 8) 56 #define AD7879_MODE_NOC (0 << 10) /* Do not convert */ 57 #define AD7879_MODE_SCC (1 << 10) /* Single channel conversion */ 58 #define AD7879_MODE_SEQ0 (2 << 10) /* Sequence 0 in Slave Mode */ 59 #define AD7879_MODE_SEQ1 (3 << 10) /* Sequence 1 in Master Mode */ 60 #define AD7879_MODE_INT (1 << 15) /* PENIRQ disabled INT enabled */ 61 62 /* Control REG 2 */ 63 #define AD7879_FCD(x) ((x & 0x3) << 0) 64 #define AD7879_RESET (1 << 4) 65 #define AD7879_MFS(x) ((x & 0x3) << 5) 66 #define AD7879_AVG(x) ((x & 0x3) << 7) 67 #define AD7879_SER (1 << 9) /* non-differential */ 68 #define AD7879_DFR (0 << 9) /* differential */ 69 #define AD7879_GPIOPOL (1 << 10) 70 #define AD7879_GPIODIR (1 << 11) 71 #define AD7879_GPIO_DATA (1 << 12) 72 #define AD7879_GPIO_EN (1 << 13) 73 #define AD7879_PM(x) ((x & 0x3) << 14) 74 #define AD7879_PM_SHUTDOWN (0) 75 #define AD7879_PM_DYN (1) 76 #define AD7879_PM_FULLON (2) 77 78 /* Control REG 3 */ 79 #define AD7879_TEMPMASK_BIT (1<<15) 80 #define AD7879_AUXVBATMASK_BIT (1<<14) 81 #define AD7879_INTMODE_BIT (1<<13) 82 #define AD7879_GPIOALERTMASK_BIT (1<<12) 83 #define AD7879_AUXLOW_BIT (1<<11) 84 #define AD7879_AUXHIGH_BIT (1<<10) 85 #define AD7879_TEMPLOW_BIT (1<<9) 86 #define AD7879_TEMPHIGH_BIT (1<<8) 87 #define AD7879_YPLUS_BIT (1<<7) 88 #define AD7879_XPLUS_BIT (1<<6) 89 #define AD7879_Z1_BIT (1<<5) 90 #define AD7879_Z2_BIT (1<<4) 91 #define AD7879_AUX_BIT (1<<3) 92 #define AD7879_VBAT_BIT (1<<2) 93 #define AD7879_TEMP_BIT (1<<1) 94 95 enum { 96 AD7879_SEQ_YPOS = 0, 97 AD7879_SEQ_XPOS = 1, 98 AD7879_SEQ_Z1 = 2, 99 AD7879_SEQ_Z2 = 3, 100 AD7879_NR_SENSE = 4, 101 }; 102 103 #define MAX_12BIT ((1<<12)-1) 104 #define TS_PEN_UP_TIMEOUT msecs_to_jiffies(50) 105 106 struct ad7879 { 107 struct regmap *regmap; 108 struct device *dev; 109 struct input_dev *input; 110 struct timer_list timer; 111 #ifdef CONFIG_GPIOLIB 112 struct gpio_chip gc; 113 struct mutex mutex; 114 #endif 115 unsigned int irq; 116 bool disabled; /* P: input->mutex */ 117 bool suspended; /* P: input->mutex */ 118 bool swap_xy; 119 u16 conversion_data[AD7879_NR_SENSE]; 120 char phys[32]; 121 u8 first_conversion_delay; 122 u8 acquisition_time; 123 u8 averaging; 124 u8 pen_down_acc_interval; 125 u8 median; 126 u16 x_plate_ohms; 127 u16 cmd_crtl1; 128 u16 cmd_crtl2; 129 u16 cmd_crtl3; 130 int x; 131 int y; 132 int Rt; 133 }; 134 135 static int ad7879_read(struct ad7879 *ts, u8 reg) 136 { 137 unsigned int val; 138 int error; 139 140 error = regmap_read(ts->regmap, reg, &val); 141 if (error) { 142 dev_err(ts->dev, "failed to read register %#02x: %d\n", 143 reg, error); 144 return error; 145 } 146 147 return val; 148 } 149 150 static int ad7879_write(struct ad7879 *ts, u8 reg, u16 val) 151 { 152 int error; 153 154 error = regmap_write(ts->regmap, reg, val); 155 if (error) { 156 dev_err(ts->dev, 157 "failed to write %#04x to register %#02x: %d\n", 158 val, reg, error); 159 return error; 160 } 161 162 return 0; 163 } 164 165 static int ad7879_report(struct ad7879 *ts) 166 { 167 struct input_dev *input_dev = ts->input; 168 unsigned Rt; 169 u16 x, y, z1, z2; 170 171 x = ts->conversion_data[AD7879_SEQ_XPOS] & MAX_12BIT; 172 y = ts->conversion_data[AD7879_SEQ_YPOS] & MAX_12BIT; 173 z1 = ts->conversion_data[AD7879_SEQ_Z1] & MAX_12BIT; 174 z2 = ts->conversion_data[AD7879_SEQ_Z2] & MAX_12BIT; 175 176 if (ts->swap_xy) 177 swap(x, y); 178 179 /* 180 * The samples processed here are already preprocessed by the AD7879. 181 * The preprocessing function consists of a median and an averaging 182 * filter. The combination of these two techniques provides a robust 183 * solution, discarding the spurious noise in the signal and keeping 184 * only the data of interest. The size of both filters is 185 * programmable. (dev.platform_data, see linux/platform_data/ad7879.h) 186 * Other user-programmable conversion controls include variable 187 * acquisition time, and first conversion delay. Up to 16 averages can 188 * be taken per conversion. 189 */ 190 191 if (likely(x && z1)) { 192 /* compute touch pressure resistance using equation #1 */ 193 Rt = (z2 - z1) * x * ts->x_plate_ohms; 194 Rt /= z1; 195 Rt = (Rt + 2047) >> 12; 196 197 /* 198 * Sample found inconsistent, pressure is beyond 199 * the maximum. Don't report it to user space. 200 */ 201 if (Rt > input_abs_get_max(input_dev, ABS_PRESSURE)) 202 return -EINVAL; 203 204 /* 205 * Note that we delay reporting events by one sample. 206 * This is done to avoid reporting last sample of the 207 * touch sequence, which may be incomplete if finger 208 * leaves the surface before last reading is taken. 209 */ 210 if (timer_pending(&ts->timer)) { 211 /* Touch continues */ 212 input_report_key(input_dev, BTN_TOUCH, 1); 213 input_report_abs(input_dev, ABS_X, ts->x); 214 input_report_abs(input_dev, ABS_Y, ts->y); 215 input_report_abs(input_dev, ABS_PRESSURE, ts->Rt); 216 input_sync(input_dev); 217 } 218 219 ts->x = x; 220 ts->y = y; 221 ts->Rt = Rt; 222 223 return 0; 224 } 225 226 return -EINVAL; 227 } 228 229 static void ad7879_ts_event_release(struct ad7879 *ts) 230 { 231 struct input_dev *input_dev = ts->input; 232 233 input_report_abs(input_dev, ABS_PRESSURE, 0); 234 input_report_key(input_dev, BTN_TOUCH, 0); 235 input_sync(input_dev); 236 } 237 238 static void ad7879_timer(struct timer_list *t) 239 { 240 struct ad7879 *ts = from_timer(ts, t, timer); 241 242 ad7879_ts_event_release(ts); 243 } 244 245 static irqreturn_t ad7879_irq(int irq, void *handle) 246 { 247 struct ad7879 *ts = handle; 248 int error; 249 250 error = regmap_bulk_read(ts->regmap, AD7879_REG_XPLUS, 251 ts->conversion_data, AD7879_NR_SENSE); 252 if (error) 253 dev_err_ratelimited(ts->dev, "failed to read %#02x: %d\n", 254 AD7879_REG_XPLUS, error); 255 else if (!ad7879_report(ts)) 256 mod_timer(&ts->timer, jiffies + TS_PEN_UP_TIMEOUT); 257 258 return IRQ_HANDLED; 259 } 260 261 static void __ad7879_enable(struct ad7879 *ts) 262 { 263 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); 264 ad7879_write(ts, AD7879_REG_CTRL3, ts->cmd_crtl3); 265 ad7879_write(ts, AD7879_REG_CTRL1, ts->cmd_crtl1); 266 267 enable_irq(ts->irq); 268 } 269 270 static void __ad7879_disable(struct ad7879 *ts) 271 { 272 u16 reg = (ts->cmd_crtl2 & ~AD7879_PM(-1)) | 273 AD7879_PM(AD7879_PM_SHUTDOWN); 274 disable_irq(ts->irq); 275 276 if (del_timer_sync(&ts->timer)) 277 ad7879_ts_event_release(ts); 278 279 ad7879_write(ts, AD7879_REG_CTRL2, reg); 280 } 281 282 283 static int ad7879_open(struct input_dev *input) 284 { 285 struct ad7879 *ts = input_get_drvdata(input); 286 287 /* protected by input->mutex */ 288 if (!ts->disabled && !ts->suspended) 289 __ad7879_enable(ts); 290 291 return 0; 292 } 293 294 static void ad7879_close(struct input_dev *input) 295 { 296 struct ad7879 *ts = input_get_drvdata(input); 297 298 /* protected by input->mutex */ 299 if (!ts->disabled && !ts->suspended) 300 __ad7879_disable(ts); 301 } 302 303 static int __maybe_unused ad7879_suspend(struct device *dev) 304 { 305 struct ad7879 *ts = dev_get_drvdata(dev); 306 307 mutex_lock(&ts->input->mutex); 308 309 if (!ts->suspended && !ts->disabled && ts->input->users) 310 __ad7879_disable(ts); 311 312 ts->suspended = true; 313 314 mutex_unlock(&ts->input->mutex); 315 316 return 0; 317 } 318 319 static int __maybe_unused ad7879_resume(struct device *dev) 320 { 321 struct ad7879 *ts = dev_get_drvdata(dev); 322 323 mutex_lock(&ts->input->mutex); 324 325 if (ts->suspended && !ts->disabled && ts->input->users) 326 __ad7879_enable(ts); 327 328 ts->suspended = false; 329 330 mutex_unlock(&ts->input->mutex); 331 332 return 0; 333 } 334 335 SIMPLE_DEV_PM_OPS(ad7879_pm_ops, ad7879_suspend, ad7879_resume); 336 EXPORT_SYMBOL(ad7879_pm_ops); 337 338 static void ad7879_toggle(struct ad7879 *ts, bool disable) 339 { 340 mutex_lock(&ts->input->mutex); 341 342 if (!ts->suspended && ts->input->users != 0) { 343 344 if (disable) { 345 if (ts->disabled) 346 __ad7879_enable(ts); 347 } else { 348 if (!ts->disabled) 349 __ad7879_disable(ts); 350 } 351 } 352 353 ts->disabled = disable; 354 355 mutex_unlock(&ts->input->mutex); 356 } 357 358 static ssize_t ad7879_disable_show(struct device *dev, 359 struct device_attribute *attr, char *buf) 360 { 361 struct ad7879 *ts = dev_get_drvdata(dev); 362 363 return sprintf(buf, "%u\n", ts->disabled); 364 } 365 366 static ssize_t ad7879_disable_store(struct device *dev, 367 struct device_attribute *attr, 368 const char *buf, size_t count) 369 { 370 struct ad7879 *ts = dev_get_drvdata(dev); 371 unsigned int val; 372 int error; 373 374 error = kstrtouint(buf, 10, &val); 375 if (error) 376 return error; 377 378 ad7879_toggle(ts, val); 379 380 return count; 381 } 382 383 static DEVICE_ATTR(disable, 0664, ad7879_disable_show, ad7879_disable_store); 384 385 static struct attribute *ad7879_attributes[] = { 386 &dev_attr_disable.attr, 387 NULL 388 }; 389 390 static const struct attribute_group ad7879_attr_group = { 391 .attrs = ad7879_attributes, 392 }; 393 394 #ifdef CONFIG_GPIOLIB 395 static int ad7879_gpio_direction_input(struct gpio_chip *chip, 396 unsigned gpio) 397 { 398 struct ad7879 *ts = gpiochip_get_data(chip); 399 int err; 400 401 mutex_lock(&ts->mutex); 402 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIODIR | AD7879_GPIOPOL; 403 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); 404 mutex_unlock(&ts->mutex); 405 406 return err; 407 } 408 409 static int ad7879_gpio_direction_output(struct gpio_chip *chip, 410 unsigned gpio, int level) 411 { 412 struct ad7879 *ts = gpiochip_get_data(chip); 413 int err; 414 415 mutex_lock(&ts->mutex); 416 ts->cmd_crtl2 &= ~AD7879_GPIODIR; 417 ts->cmd_crtl2 |= AD7879_GPIO_EN | AD7879_GPIOPOL; 418 if (level) 419 ts->cmd_crtl2 |= AD7879_GPIO_DATA; 420 else 421 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA; 422 423 err = ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); 424 mutex_unlock(&ts->mutex); 425 426 return err; 427 } 428 429 static int ad7879_gpio_get_value(struct gpio_chip *chip, unsigned gpio) 430 { 431 struct ad7879 *ts = gpiochip_get_data(chip); 432 u16 val; 433 434 mutex_lock(&ts->mutex); 435 val = ad7879_read(ts, AD7879_REG_CTRL2); 436 mutex_unlock(&ts->mutex); 437 438 return !!(val & AD7879_GPIO_DATA); 439 } 440 441 static void ad7879_gpio_set_value(struct gpio_chip *chip, 442 unsigned gpio, int value) 443 { 444 struct ad7879 *ts = gpiochip_get_data(chip); 445 446 mutex_lock(&ts->mutex); 447 if (value) 448 ts->cmd_crtl2 |= AD7879_GPIO_DATA; 449 else 450 ts->cmd_crtl2 &= ~AD7879_GPIO_DATA; 451 452 ad7879_write(ts, AD7879_REG_CTRL2, ts->cmd_crtl2); 453 mutex_unlock(&ts->mutex); 454 } 455 456 static int ad7879_gpio_add(struct ad7879 *ts) 457 { 458 int ret = 0; 459 460 mutex_init(&ts->mutex); 461 462 /* Do not create a chip unless flagged for it */ 463 if (!device_property_read_bool(ts->dev, "gpio-controller")) 464 return 0; 465 466 ts->gc.direction_input = ad7879_gpio_direction_input; 467 ts->gc.direction_output = ad7879_gpio_direction_output; 468 ts->gc.get = ad7879_gpio_get_value; 469 ts->gc.set = ad7879_gpio_set_value; 470 ts->gc.can_sleep = 1; 471 ts->gc.base = -1; 472 ts->gc.ngpio = 1; 473 ts->gc.label = "AD7879-GPIO"; 474 ts->gc.owner = THIS_MODULE; 475 ts->gc.parent = ts->dev; 476 477 ret = devm_gpiochip_add_data(ts->dev, &ts->gc, ts); 478 if (ret) 479 dev_err(ts->dev, "failed to register gpio %d\n", 480 ts->gc.base); 481 482 return ret; 483 } 484 #else 485 static int ad7879_gpio_add(struct ad7879 *ts) 486 { 487 return 0; 488 } 489 #endif 490 491 static int ad7879_parse_dt(struct device *dev, struct ad7879 *ts) 492 { 493 int err; 494 u32 tmp; 495 496 err = device_property_read_u32(dev, "adi,resistance-plate-x", &tmp); 497 if (err) { 498 dev_err(dev, "failed to get resistance-plate-x property\n"); 499 return err; 500 } 501 ts->x_plate_ohms = (u16)tmp; 502 503 device_property_read_u8(dev, "adi,first-conversion-delay", 504 &ts->first_conversion_delay); 505 device_property_read_u8(dev, "adi,acquisition-time", 506 &ts->acquisition_time); 507 device_property_read_u8(dev, "adi,median-filter-size", &ts->median); 508 device_property_read_u8(dev, "adi,averaging", &ts->averaging); 509 device_property_read_u8(dev, "adi,conversion-interval", 510 &ts->pen_down_acc_interval); 511 512 ts->swap_xy = device_property_read_bool(dev, "touchscreen-swapped-x-y"); 513 514 return 0; 515 } 516 517 int ad7879_probe(struct device *dev, struct regmap *regmap, 518 int irq, u16 bustype, u8 devid) 519 { 520 struct ad7879 *ts; 521 struct input_dev *input_dev; 522 int err; 523 u16 revid; 524 525 if (irq <= 0) { 526 dev_err(dev, "No IRQ specified\n"); 527 return -EINVAL; 528 } 529 530 ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL); 531 if (!ts) 532 return -ENOMEM; 533 534 err = ad7879_parse_dt(dev, ts); 535 if (err) 536 return err; 537 538 input_dev = devm_input_allocate_device(dev); 539 if (!input_dev) { 540 dev_err(dev, "Failed to allocate input device\n"); 541 return -ENOMEM; 542 } 543 544 ts->dev = dev; 545 ts->input = input_dev; 546 ts->irq = irq; 547 ts->regmap = regmap; 548 549 timer_setup(&ts->timer, ad7879_timer, 0); 550 snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(dev)); 551 552 input_dev->name = "AD7879 Touchscreen"; 553 input_dev->phys = ts->phys; 554 input_dev->dev.parent = dev; 555 input_dev->id.bustype = bustype; 556 557 input_dev->open = ad7879_open; 558 input_dev->close = ad7879_close; 559 560 input_set_drvdata(input_dev, ts); 561 562 input_set_capability(input_dev, EV_KEY, BTN_TOUCH); 563 564 input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0); 565 input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0); 566 input_set_capability(input_dev, EV_ABS, ABS_PRESSURE); 567 touchscreen_parse_properties(input_dev, false, NULL); 568 if (!input_abs_get_max(input_dev, ABS_PRESSURE)) { 569 dev_err(dev, "Touchscreen pressure is not specified\n"); 570 return -EINVAL; 571 } 572 573 err = ad7879_write(ts, AD7879_REG_CTRL2, AD7879_RESET); 574 if (err < 0) { 575 dev_err(dev, "Failed to write %s\n", input_dev->name); 576 return err; 577 } 578 579 revid = ad7879_read(ts, AD7879_REG_REVID); 580 input_dev->id.product = (revid & 0xff); 581 input_dev->id.version = revid >> 8; 582 if (input_dev->id.product != devid) { 583 dev_err(dev, "Failed to probe %s (%x vs %x)\n", 584 input_dev->name, devid, revid); 585 return -ENODEV; 586 } 587 588 ts->cmd_crtl3 = AD7879_YPLUS_BIT | 589 AD7879_XPLUS_BIT | 590 AD7879_Z2_BIT | 591 AD7879_Z1_BIT | 592 AD7879_TEMPMASK_BIT | 593 AD7879_AUXVBATMASK_BIT | 594 AD7879_GPIOALERTMASK_BIT; 595 596 ts->cmd_crtl2 = AD7879_PM(AD7879_PM_DYN) | AD7879_DFR | 597 AD7879_AVG(ts->averaging) | 598 AD7879_MFS(ts->median) | 599 AD7879_FCD(ts->first_conversion_delay); 600 601 ts->cmd_crtl1 = AD7879_MODE_INT | AD7879_MODE_SEQ1 | 602 AD7879_ACQ(ts->acquisition_time) | 603 AD7879_TMR(ts->pen_down_acc_interval); 604 605 err = devm_request_threaded_irq(dev, ts->irq, NULL, ad7879_irq, 606 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 607 dev_name(dev), ts); 608 if (err) { 609 dev_err(dev, "Failed to request IRQ: %d\n", err); 610 return err; 611 } 612 613 __ad7879_disable(ts); 614 615 err = devm_device_add_group(dev, &ad7879_attr_group); 616 if (err) 617 return err; 618 619 err = ad7879_gpio_add(ts); 620 if (err) 621 return err; 622 623 err = input_register_device(input_dev); 624 if (err) 625 return err; 626 627 dev_set_drvdata(dev, ts); 628 629 return 0; 630 } 631 EXPORT_SYMBOL(ad7879_probe); 632 633 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 634 MODULE_DESCRIPTION("AD7879(-1) touchscreen Driver"); 635 MODULE_LICENSE("GPL"); 636