drivers/input/touchscreen/ads7846.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ADS7846 based touchscreen and sensor driver
   4  *
   5  * Copyright (c) 2005 David Brownell
   6  * Copyright (c) 2006 Nokia Corporation
   7  * Various changes: Imre Deak <imre.deak@nokia.com>
   8  *
   9  * Using code from:
  10  *  - corgi_ts.c
  11  *      Copyright (C) 2004-2005 Richard Purdie
  12  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  13  *      Copyright (C) 2002 MontaVista Software
  14  *      Copyright (C) 2004 Texas Instruments
  15  *      Copyright (C) 2005 Dirk Behme
  16  */
  17 #include <linux/types.h>
  18 #include <linux/hwmon.h>
  19 #include <linux/err.h>
  20 #include <linux/sched.h>
  21 #include <linux/delay.h>
  22 #include <linux/input.h>
  23 #include <linux/input/touchscreen.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/slab.h>
  26 #include <linux/pm.h>
  27 #include <linux/of.h>
  28 #include <linux/of_gpio.h>
  29 #include <linux/of_device.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/unaligned.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 ads7846_buf {
  66         u8 cmd;
  67         /*
  68          * This union is a temporary hack. The driver does an in-place
  69          * endianness conversion. This will be cleaned up in the next
  70          * patch.
  71          */
  72         union {
  73                 __be16 data_be16;
  74                 u16 data;
  75         };
  76 } __packed;
  77
  78
  79 struct ts_event {
  80         bool ignore;
  81         struct ads7846_buf x;
  82         struct ads7846_buf y;
  83         struct ads7846_buf z1;
  84         struct ads7846_buf z2;
  85 };
  86
  87 /*
  88  * We allocate this separately to avoid cache line sharing issues when
  89  * driver is used with DMA-based SPI controllers (like atmel_spi) on
  90  * systems where main memory is not DMA-coherent (most non-x86 boards).
  91  */
  92 struct ads7846_packet {
  93         struct ts_event tc;
  94         struct ads7846_buf read_x_cmd;
  95         struct ads7846_buf read_y_cmd;
  96         struct ads7846_buf read_z1_cmd;
  97         struct ads7846_buf read_z2_cmd;
  98         struct ads7846_buf pwrdown_cmd;
  99 };
 100
 101 struct ads7846 {
 102         struct input_dev        *input;
 103         char                    phys[32];
 104         char                    name[32];
 105
 106         struct spi_device       *spi;
 107         struct regulator        *reg;
 108
 109 #if IS_ENABLED(CONFIG_HWMON)
 110         struct device           *hwmon;
 111 #endif
 112
 113         u16                     model;
 114         u16                     vref_mv;
 115         u16                     vref_delay_usecs;
 116         u16                     x_plate_ohms;
 117         u16                     pressure_max;
 118
 119         bool                    swap_xy;
 120         bool                    use_internal;
 121
 122         struct ads7846_packet   *packet;
 123
 124         struct spi_transfer     xfer[18];
 125         struct spi_message      msg[5];
 126         int                     msg_count;
 127         wait_queue_head_t       wait;
 128
 129         bool                    pendown;
 130
 131         int                     read_cnt;
 132         int                     read_rep;
 133         int                     last_read;
 134
 135         u16                     debounce_max;
 136         u16                     debounce_tol;
 137         u16                     debounce_rep;
 138
 139         u16                     penirq_recheck_delay_usecs;
 140
 141         struct touchscreen_properties core_prop;
 142
 143         struct mutex            lock;
 144         bool                    stopped;        /* P: lock */
 145         bool                    disabled;       /* P: lock */
 146         bool                    suspended;      /* P: lock */
 147
 148         int                     (*filter)(void *data, int data_idx, int *val);
 149         void                    *filter_data;
 150         void                    (*filter_cleanup)(void *data);
 151         int                     (*get_pendown_state)(void);
 152         int                     gpio_pendown;
 153
 154         void                    (*wait_for_sync)(void);
 155 };
 156
 157 /* leave chip selected when we're done, for quicker re-select? */
 158 #if     0
 159 #define CS_CHANGE(xfer) ((xfer).cs_change = 1)
 160 #else
 161 #define CS_CHANGE(xfer) ((xfer).cs_change = 0)
 162 #endif
 163
 164 /*--------------------------------------------------------------------------*/
 165
 166 /* The ADS7846 has touchscreen and other sensors.
 167  * Earlier ads784x chips are somewhat compatible.
 168  */
 169 #define ADS_START               (1 << 7)
 170 #define ADS_A2A1A0_d_y          (1 << 4)        /* differential */
 171 #define ADS_A2A1A0_d_z1         (3 << 4)        /* differential */
 172 #define ADS_A2A1A0_d_z2         (4 << 4)        /* differential */
 173 #define ADS_A2A1A0_d_x          (5 << 4)        /* differential */
 174 #define ADS_A2A1A0_temp0        (0 << 4)        /* non-differential */
 175 #define ADS_A2A1A0_vbatt        (2 << 4)        /* non-differential */
 176 #define ADS_A2A1A0_vaux         (6 << 4)        /* non-differential */
 177 #define ADS_A2A1A0_temp1        (7 << 4)        /* non-differential */
 178 #define ADS_8_BIT               (1 << 3)
 179 #define ADS_12_BIT              (0 << 3)
 180 #define ADS_SER                 (1 << 2)        /* non-differential */
 181 #define ADS_DFR                 (0 << 2)        /* differential */
 182 #define ADS_PD10_PDOWN          (0 << 0)        /* low power mode + penirq */
 183 #define ADS_PD10_ADC_ON         (1 << 0)        /* ADC on */
 184 #define ADS_PD10_REF_ON         (2 << 0)        /* vREF on + penirq */
 185 #define ADS_PD10_ALL_ON         (3 << 0)        /* ADC + vREF on */
 186
 187 #define MAX_12BIT       ((1<<12)-1)
 188
 189 /* leave ADC powered up (disables penirq) between differential samples */
 190 #define READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
 191         | ADS_12_BIT | ADS_DFR | \
 192         (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
 193
 194 #define READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
 195 #define READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
 196 #define READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
 197
 198 #define READ_X(vref)    (READ_12BIT_DFR(x,  1, vref))
 199 #define PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* LAST */
 200
 201 /* single-ended samples need to first power up reference voltage;
 202  * we leave both ADC and VREF powered
 203  */
 204 #define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
 205         | ADS_12_BIT | ADS_SER)
 206
 207 #define REF_ON  (READ_12BIT_DFR(x, 1, 1))
 208 #define REF_OFF (READ_12BIT_DFR(y, 0, 0))
 209
 210 static int get_pendown_state(struct ads7846 *ts)
 211 {
 212         if (ts->get_pendown_state)
 213                 return ts->get_pendown_state();
 214
 215         return !gpio_get_value(ts->gpio_pendown);
 216 }
 217
 218 static void ads7846_report_pen_up(struct ads7846 *ts)
 219 {
 220         struct input_dev *input = ts->input;
 221
 222         input_report_key(input, BTN_TOUCH, 0);
 223         input_report_abs(input, ABS_PRESSURE, 0);
 224         input_sync(input);
 225
 226         ts->pendown = false;
 227         dev_vdbg(&ts->spi->dev, "UP\n");
 228 }
 229
 230 /* Must be called with ts->lock held */
 231 static void ads7846_stop(struct ads7846 *ts)
 232 {
 233         if (!ts->disabled && !ts->suspended) {
 234                 /* Signal IRQ thread to stop polling and disable the handler. */
 235                 ts->stopped = true;
 236                 mb();
 237                 wake_up(&ts->wait);
 238                 disable_irq(ts->spi->irq);
 239         }
 240 }
 241
 242 /* Must be called with ts->lock held */
 243 static void ads7846_restart(struct ads7846 *ts)
 244 {
 245         if (!ts->disabled && !ts->suspended) {
 246                 /* Check if pen was released since last stop */
 247                 if (ts->pendown && !get_pendown_state(ts))
 248                         ads7846_report_pen_up(ts);
 249
 250                 /* Tell IRQ thread that it may poll the device. */
 251                 ts->stopped = false;
 252                 mb();
 253                 enable_irq(ts->spi->irq);
 254         }
 255 }
 256
 257 /* Must be called with ts->lock held */
 258 static void __ads7846_disable(struct ads7846 *ts)
 259 {
 260         ads7846_stop(ts);
 261         regulator_disable(ts->reg);
 262
 263         /*
 264          * We know the chip's in low power mode since we always
 265          * leave it that way after every request
 266          */
 267 }
 268
 269 /* Must be called with ts->lock held */
 270 static void __ads7846_enable(struct ads7846 *ts)
 271 {
 272         int error;
 273
 274         error = regulator_enable(ts->reg);
 275         if (error != 0)
 276                 dev_err(&ts->spi->dev, "Failed to enable supply: %d\n", error);
 277
 278         ads7846_restart(ts);
 279 }
 280
 281 static void ads7846_disable(struct ads7846 *ts)
 282 {
 283         mutex_lock(&ts->lock);
 284
 285         if (!ts->disabled) {
 286
 287                 if  (!ts->suspended)
 288                         __ads7846_disable(ts);
 289
 290                 ts->disabled = true;
 291         }
 292
 293         mutex_unlock(&ts->lock);
 294 }
 295
 296 static void ads7846_enable(struct ads7846 *ts)
 297 {
 298         mutex_lock(&ts->lock);
 299
 300         if (ts->disabled) {
 301
 302                 ts->disabled = false;
 303
 304                 if (!ts->suspended)
 305                         __ads7846_enable(ts);
 306         }
 307
 308         mutex_unlock(&ts->lock);
 309 }
 310
 311 /*--------------------------------------------------------------------------*/
 312
 313 /*
 314  * Non-touchscreen sensors only use single-ended conversions.
 315  * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
 316  * ads7846 lets that pin be unconnected, to use internal vREF.
 317  */
 318
 319 struct ser_req {
 320         u8                      ref_on;
 321         u8                      command;
 322         u8                      ref_off;
 323         u16                     scratch;
 324         struct spi_message      msg;
 325         struct spi_transfer     xfer[6];
 326         /*
 327          * DMA (thus cache coherency maintenance) requires the
 328          * transfer buffers to live in their own cache lines.
 329          */
 330         __be16 sample ____cacheline_aligned;
 331 };
 332
 333 struct ads7845_ser_req {
 334         u8                      command[3];
 335         struct spi_message      msg;
 336         struct spi_transfer     xfer[2];
 337         /*
 338          * DMA (thus cache coherency maintenance) requires the
 339          * transfer buffers to live in their own cache lines.
 340          */
 341         u8 sample[3] ____cacheline_aligned;
 342 };
 343
 344 static int ads7846_read12_ser(struct device *dev, unsigned command)
 345 {
 346         struct spi_device *spi = to_spi_device(dev);
 347         struct ads7846 *ts = dev_get_drvdata(dev);
 348         struct ser_req *req;
 349         int status;
 350
 351         req = kzalloc(sizeof *req, GFP_KERNEL);
 352         if (!req)
 353                 return -ENOMEM;
 354
 355         spi_message_init(&req->msg);
 356
 357         /* maybe turn on internal vREF, and let it settle */
 358         if (ts->use_internal) {
 359                 req->ref_on = REF_ON;
 360                 req->xfer[0].tx_buf = &req->ref_on;
 361                 req->xfer[0].len = 1;
 362                 spi_message_add_tail(&req->xfer[0], &req->msg);
 363
 364                 req->xfer[1].rx_buf = &req->scratch;
 365                 req->xfer[1].len = 2;
 366
 367                 /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
 368                 req->xfer[1].delay.value = ts->vref_delay_usecs;
 369                 req->xfer[1].delay.unit = SPI_DELAY_UNIT_USECS;
 370                 spi_message_add_tail(&req->xfer[1], &req->msg);
 371
 372                 /* Enable reference voltage */
 373                 command |= ADS_PD10_REF_ON;
 374         }
 375
 376         /* Enable ADC in every case */
 377         command |= ADS_PD10_ADC_ON;
 378
 379         /* take sample */
 380         req->command = (u8) command;
 381         req->xfer[2].tx_buf = &req->command;
 382         req->xfer[2].len = 1;
 383         spi_message_add_tail(&req->xfer[2], &req->msg);
 384
 385         req->xfer[3].rx_buf = &req->sample;
 386         req->xfer[3].len = 2;
 387         spi_message_add_tail(&req->xfer[3], &req->msg);
 388
 389         /* REVISIT:  take a few more samples, and compare ... */
 390
 391         /* converter in low power mode & enable PENIRQ */
 392         req->ref_off = PWRDOWN;
 393         req->xfer[4].tx_buf = &req->ref_off;
 394         req->xfer[4].len = 1;
 395         spi_message_add_tail(&req->xfer[4], &req->msg);
 396
 397         req->xfer[5].rx_buf = &req->scratch;
 398         req->xfer[5].len = 2;
 399         CS_CHANGE(req->xfer[5]);
 400         spi_message_add_tail(&req->xfer[5], &req->msg);
 401
 402         mutex_lock(&ts->lock);
 403         ads7846_stop(ts);
 404         status = spi_sync(spi, &req->msg);
 405         ads7846_restart(ts);
 406         mutex_unlock(&ts->lock);
 407
 408         if (status == 0) {
 409                 /* on-wire is a must-ignore bit, a BE12 value, then padding */
 410                 status = be16_to_cpu(req->sample);
 411                 status = status >> 3;
 412                 status &= 0x0fff;
 413         }
 414
 415         kfree(req);
 416         return status;
 417 }
 418
 419 static int ads7845_read12_ser(struct device *dev, unsigned command)
 420 {
 421         struct spi_device *spi = to_spi_device(dev);
 422         struct ads7846 *ts = dev_get_drvdata(dev);
 423         struct ads7845_ser_req *req;
 424         int status;
 425
 426         req = kzalloc(sizeof *req, GFP_KERNEL);
 427         if (!req)
 428                 return -ENOMEM;
 429
 430         spi_message_init(&req->msg);
 431
 432         req->command[0] = (u8) command;
 433         req->xfer[0].tx_buf = req->command;
 434         req->xfer[0].rx_buf = req->sample;
 435         req->xfer[0].len = 3;
 436         spi_message_add_tail(&req->xfer[0], &req->msg);
 437
 438         mutex_lock(&ts->lock);
 439         ads7846_stop(ts);
 440         status = spi_sync(spi, &req->msg);
 441         ads7846_restart(ts);
 442         mutex_unlock(&ts->lock);
 443
 444         if (status == 0) {
 445                 /* BE12 value, then padding */
 446                 status = get_unaligned_be16(&req->sample[1]);
 447                 status = status >> 3;
 448                 status &= 0x0fff;
 449         }
 450
 451         kfree(req);
 452         return status;
 453 }
 454
 455 #if IS_ENABLED(CONFIG_HWMON)
 456
 457 #define SHOW(name, var, adjust) static ssize_t \
 458 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 459 { \
 460         struct ads7846 *ts = dev_get_drvdata(dev); \
 461         ssize_t v = ads7846_read12_ser(&ts->spi->dev, \
 462                         READ_12BIT_SER(var)); \
 463         if (v < 0) \
 464                 return v; \
 465         return sprintf(buf, "%u\n", adjust(ts, v)); \
 466 } \
 467 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 468
 469
 470 /* Sysfs conventions report temperatures in millidegrees Celsius.
 471  * ADS7846 could use the low-accuracy two-sample scheme, but can't do the high
 472  * accuracy scheme without calibration data.  For now we won't try either;
 473  * userspace sees raw sensor values, and must scale/calibrate appropriately.
 474  */
 475 static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
 476 {
 477         return v;
 478 }
 479
 480 SHOW(temp0, temp0, null_adjust)         /* temp1_input */
 481 SHOW(temp1, temp1, null_adjust)         /* temp2_input */
 482
 483
 484 /* sysfs conventions report voltages in millivolts.  We can convert voltages
 485  * if we know vREF.  userspace may need to scale vAUX to match the board's
 486  * external resistors; we assume that vBATT only uses the internal ones.
 487  */
 488 static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
 489 {
 490         unsigned retval = v;
 491
 492         /* external resistors may scale vAUX into 0..vREF */
 493         retval *= ts->vref_mv;
 494         retval = retval >> 12;
 495
 496         return retval;
 497 }
 498
 499 static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
 500 {
 501         unsigned retval = vaux_adjust(ts, v);
 502
 503         /* ads7846 has a resistor ladder to scale this signal down */
 504         if (ts->model == 7846)
 505                 retval *= 4;
 506
 507         return retval;
 508 }
 509
 510 SHOW(in0_input, vaux, vaux_adjust)
 511 SHOW(in1_input, vbatt, vbatt_adjust)
 512
 513 static umode_t ads7846_is_visible(struct kobject *kobj, struct attribute *attr,
 514                                   int index)
 515 {
 516         struct device *dev = kobj_to_dev(kobj);
 517         struct ads7846 *ts = dev_get_drvdata(dev);
 518
 519         if (ts->model == 7843 && index < 2)     /* in0, in1 */
 520                 return 0;
 521         if (ts->model == 7845 && index != 2)    /* in0 */
 522                 return 0;
 523
 524         return attr->mode;
 525 }
 526
 527 static struct attribute *ads7846_attributes[] = {
 528         &dev_attr_temp0.attr,           /* 0 */
 529         &dev_attr_temp1.attr,           /* 1 */
 530         &dev_attr_in0_input.attr,       /* 2 */
 531         &dev_attr_in1_input.attr,       /* 3 */
 532         NULL,
 533 };
 534
 535 static const struct attribute_group ads7846_attr_group = {
 536         .attrs = ads7846_attributes,
 537         .is_visible = ads7846_is_visible,
 538 };
 539 __ATTRIBUTE_GROUPS(ads7846_attr);
 540
 541 static int ads784x_hwmon_register(struct spi_device *spi, struct ads7846 *ts)
 542 {
 543         /* hwmon sensors need a reference voltage */
 544         switch (ts->model) {
 545         case 7846:
 546                 if (!ts->vref_mv) {
 547                         dev_dbg(&spi->dev, "assuming 2.5V internal vREF\n");
 548                         ts->vref_mv = 2500;
 549                         ts->use_internal = true;
 550                 }
 551                 break;
 552         case 7845:
 553         case 7843:
 554                 if (!ts->vref_mv) {
 555                         dev_warn(&spi->dev,
 556                                 "external vREF for ADS%d not specified\n",
 557                                 ts->model);
 558                         return 0;
 559                 }
 560                 break;
 561         }
 562
 563         ts->hwmon = hwmon_device_register_with_groups(&spi->dev, spi->modalias,
 564                                                       ts, ads7846_attr_groups);
 565
 566         return PTR_ERR_OR_ZERO(ts->hwmon);
 567 }
 568
 569 static void ads784x_hwmon_unregister(struct spi_device *spi,
 570                                      struct ads7846 *ts)
 571 {
 572         if (ts->hwmon)
 573                 hwmon_device_unregister(ts->hwmon);
 574 }
 575
 576 #else
 577 static inline int ads784x_hwmon_register(struct spi_device *spi,
 578                                          struct ads7846 *ts)
 579 {
 580         return 0;
 581 }
 582
 583 static inline void ads784x_hwmon_unregister(struct spi_device *spi,
 584                                             struct ads7846 *ts)
 585 {
 586 }
 587 #endif
 588
 589 static ssize_t ads7846_pen_down_show(struct device *dev,
 590                                      struct device_attribute *attr, char *buf)
 591 {
 592         struct ads7846 *ts = dev_get_drvdata(dev);
 593
 594         return sprintf(buf, "%u\n", ts->pendown);
 595 }
 596
 597 static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
 598
 599 static ssize_t ads7846_disable_show(struct device *dev,
 600                                      struct device_attribute *attr, char *buf)
 601 {
 602         struct ads7846 *ts = dev_get_drvdata(dev);
 603
 604         return sprintf(buf, "%u\n", ts->disabled);
 605 }
 606
 607 static ssize_t ads7846_disable_store(struct device *dev,
 608                                      struct device_attribute *attr,
 609                                      const char *buf, size_t count)
 610 {
 611         struct ads7846 *ts = dev_get_drvdata(dev);
 612         unsigned int i;
 613         int err;
 614
 615         err = kstrtouint(buf, 10, &i);
 616         if (err)
 617                 return err;
 618
 619         if (i)
 620                 ads7846_disable(ts);
 621         else
 622                 ads7846_enable(ts);
 623
 624         return count;
 625 }
 626
 627 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 628
 629 static struct attribute *ads784x_attributes[] = {
 630         &dev_attr_pen_down.attr,
 631         &dev_attr_disable.attr,
 632         NULL,
 633 };
 634
 635 static const struct attribute_group ads784x_attr_group = {
 636         .attrs = ads784x_attributes,
 637 };
 638
 639 /*--------------------------------------------------------------------------*/
 640
 641 static void null_wait_for_sync(void)
 642 {
 643 }
 644
 645 static int ads7846_debounce_filter(void *ads, int data_idx, int *val)
 646 {
 647         struct ads7846 *ts = ads;
 648
 649         if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
 650                 /* Start over collecting consistent readings. */
 651                 ts->read_rep = 0;
 652                 /*
 653                  * Repeat it, if this was the first read or the read
 654                  * wasn't consistent enough.
 655                  */
 656                 if (ts->read_cnt < ts->debounce_max) {
 657                         ts->last_read = *val;
 658                         ts->read_cnt++;
 659                         return ADS7846_FILTER_REPEAT;
 660                 } else {
 661                         /*
 662                          * Maximum number of debouncing reached and still
 663                          * not enough number of consistent readings. Abort
 664                          * the whole sample, repeat it in the next sampling
 665                          * period.
 666                          */
 667                         ts->read_cnt = 0;
 668                         return ADS7846_FILTER_IGNORE;
 669                 }
 670         } else {
 671                 if (++ts->read_rep > ts->debounce_rep) {
 672                         /*
 673                          * Got a good reading for this coordinate,
 674                          * go for the next one.
 675                          */
 676                         ts->read_cnt = 0;
 677                         ts->read_rep = 0;
 678                         return ADS7846_FILTER_OK;
 679                 } else {
 680                         /* Read more values that are consistent. */
 681                         ts->read_cnt++;
 682                         return ADS7846_FILTER_REPEAT;
 683                 }
 684         }
 685 }
 686
 687 static int ads7846_no_filter(void *ads, int data_idx, int *val)
 688 {
 689         return ADS7846_FILTER_OK;
 690 }
 691
 692 static int ads7846_get_value(struct ads7846 *ts, struct spi_message *m)
 693 {
 694         int value;
 695         struct spi_transfer *t =
 696                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 697         struct ads7846_buf *buf = t->rx_buf;
 698
 699         value = be16_to_cpup(&buf->data_be16);
 700
 701         /* enforce ADC output is 12 bits width */
 702         return (value >> 3) & 0xfff;
 703 }
 704
 705 static void ads7846_update_value(struct spi_message *m, int val)
 706 {
 707         struct spi_transfer *t =
 708                 list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
 709         struct ads7846_buf *buf = t->rx_buf;
 710
 711         buf->data = val;
 712 }
 713
 714 static void ads7846_read_state(struct ads7846 *ts)
 715 {
 716         struct ads7846_packet *packet = ts->packet;
 717         struct spi_message *m;
 718         int msg_idx = 0;
 719         int val;
 720         int action;
 721         int error;
 722
 723         while (msg_idx < ts->msg_count) {
 724
 725                 ts->wait_for_sync();
 726
 727                 m = &ts->msg[msg_idx];
 728                 error = spi_sync(ts->spi, m);
 729                 if (error) {
 730                         dev_err(&ts->spi->dev, "spi_sync --> %d\n", error);
 731                         packet->tc.ignore = true;
 732                         return;
 733                 }
 734
 735                 /*
 736                  * Last message is power down request, no need to convert
 737                  * or filter the value.
 738                  */
 739                 if (msg_idx < ts->msg_count - 1) {
 740
 741                         val = ads7846_get_value(ts, m);
 742
 743                         action = ts->filter(ts->filter_data, msg_idx, &val);
 744                         switch (action) {
 745                         case ADS7846_FILTER_REPEAT:
 746                                 continue;
 747
 748                         case ADS7846_FILTER_IGNORE:
 749                                 packet->tc.ignore = true;
 750                                 msg_idx = ts->msg_count - 1;
 751                                 continue;
 752
 753                         case ADS7846_FILTER_OK:
 754                                 ads7846_update_value(m, val);
 755                                 packet->tc.ignore = false;
 756                                 msg_idx++;
 757                                 break;
 758
 759                         default:
 760                                 BUG();
 761                         }
 762                 } else {
 763                         msg_idx++;
 764                 }
 765         }
 766 }
 767
 768 static void ads7846_report_state(struct ads7846 *ts)
 769 {
 770         struct ads7846_packet *packet = ts->packet;
 771         unsigned int Rt;
 772         u16 x, y, z1, z2;
 773
 774         /*
 775          * ads7846_get_value() does in-place conversion (including byte swap)
 776          * from on-the-wire format as part of debouncing to get stable
 777          * readings.
 778          */
 779         x = packet->tc.x.data;
 780         y = packet->tc.y.data;
 781         if (ts->model == 7845) {
 782                 z1 = 0;
 783                 z2 = 0;
 784         } else {
 785                 z1 = packet->tc.z1.data;
 786                 z2 = packet->tc.z2.data;
 787         }
 788
 789         /* range filtering */
 790         if (x == MAX_12BIT)
 791                 x = 0;
 792
 793         if (ts->model == 7843) {
 794                 Rt = ts->pressure_max / 2;
 795         } else if (ts->model == 7845) {
 796                 if (get_pendown_state(ts))
 797                         Rt = ts->pressure_max / 2;
 798                 else
 799                         Rt = 0;
 800                 dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
 801         } else if (likely(x && z1)) {
 802                 /* compute touch pressure resistance using equation #2 */
 803                 Rt = z2;
 804                 Rt -= z1;
 805                 Rt *= ts->x_plate_ohms;
 806                 Rt = DIV_ROUND_CLOSEST(Rt, 16);
 807                 Rt *= x;
 808                 Rt /= z1;
 809                 Rt = DIV_ROUND_CLOSEST(Rt, 256);
 810         } else {
 811                 Rt = 0;
 812         }
 813
 814         /*
 815          * Sample found inconsistent by debouncing or pressure is beyond
 816          * the maximum. Don't report it to user space, repeat at least
 817          * once more the measurement
 818          */
 819         if (packet->tc.ignore || Rt > ts->pressure_max) {
 820                 dev_vdbg(&ts->spi->dev, "ignored %d pressure %d\n",
 821                          packet->tc.ignore, Rt);
 822                 return;
 823         }
 824
 825         /*
 826          * Maybe check the pendown state before reporting. This discards
 827          * false readings when the pen is lifted.
 828          */
 829         if (ts->penirq_recheck_delay_usecs) {
 830                 udelay(ts->penirq_recheck_delay_usecs);
 831                 if (!get_pendown_state(ts))
 832                         Rt = 0;
 833         }
 834
 835         /*
 836          * NOTE: We can't rely on the pressure to determine the pen down
 837          * state, even this controller has a pressure sensor. The pressure
 838          * value can fluctuate for quite a while after lifting the pen and
 839          * in some cases may not even settle at the expected value.
 840          *
 841          * The only safe way to check for the pen up condition is in the
 842          * timer by reading the pen signal state (it's a GPIO _and_ IRQ).
 843          */
 844         if (Rt) {
 845                 struct input_dev *input = ts->input;
 846
 847                 if (!ts->pendown) {
 848                         input_report_key(input, BTN_TOUCH, 1);
 849                         ts->pendown = true;
 850                         dev_vdbg(&ts->spi->dev, "DOWN\n");
 851                 }
 852
 853                 touchscreen_report_pos(input, &ts->core_prop, x, y, false);
 854                 input_report_abs(input, ABS_PRESSURE, ts->pressure_max - Rt);
 855
 856                 input_sync(input);
 857                 dev_vdbg(&ts->spi->dev, "%4d/%4d/%4d\n", x, y, Rt);
 858         }
 859 }
 860
 861 static irqreturn_t ads7846_hard_irq(int irq, void *handle)
 862 {
 863         struct ads7846 *ts = handle;
 864
 865         return get_pendown_state(ts) ? IRQ_WAKE_THREAD : IRQ_HANDLED;
 866 }
 867
 868
 869 static irqreturn_t ads7846_irq(int irq, void *handle)
 870 {
 871         struct ads7846 *ts = handle;
 872
 873         /* Start with a small delay before checking pendown state */
 874         msleep(TS_POLL_DELAY);
 875
 876         while (!ts->stopped && get_pendown_state(ts)) {
 877
 878                 /* pen is down, continue with the measurement */
 879                 ads7846_read_state(ts);
 880
 881                 if (!ts->stopped)
 882                         ads7846_report_state(ts);
 883
 884                 wait_event_timeout(ts->wait, ts->stopped,
 885                                    msecs_to_jiffies(TS_POLL_PERIOD));
 886         }
 887
 888         if (ts->pendown && !ts->stopped)
 889                 ads7846_report_pen_up(ts);
 890
 891         return IRQ_HANDLED;
 892 }
 893
 894 static int __maybe_unused ads7846_suspend(struct device *dev)
 895 {
 896         struct ads7846 *ts = dev_get_drvdata(dev);
 897
 898         mutex_lock(&ts->lock);
 899
 900         if (!ts->suspended) {
 901
 902                 if (!ts->disabled)
 903                         __ads7846_disable(ts);
 904
 905                 if (device_may_wakeup(&ts->spi->dev))
 906                         enable_irq_wake(ts->spi->irq);
 907
 908                 ts->suspended = true;
 909         }
 910
 911         mutex_unlock(&ts->lock);
 912
 913         return 0;
 914 }
 915
 916 static int __maybe_unused ads7846_resume(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                 ts->suspended = false;
 925
 926                 if (device_may_wakeup(&ts->spi->dev))
 927                         disable_irq_wake(ts->spi->irq);
 928
 929                 if (!ts->disabled)
 930                         __ads7846_enable(ts);
 931         }
 932
 933         mutex_unlock(&ts->lock);
 934
 935         return 0;
 936 }
 937
 938 static SIMPLE_DEV_PM_OPS(ads7846_pm, ads7846_suspend, ads7846_resume);
 939
 940 static int ads7846_setup_pendown(struct spi_device *spi,
 941                                  struct ads7846 *ts,
 942                                  const struct ads7846_platform_data *pdata)
 943 {
 944         int err;
 945
 946         /*
 947          * REVISIT when the irq can be triggered active-low, or if for some
 948          * reason the touchscreen isn't hooked up, we don't need to access
 949          * the pendown state.
 950          */
 951
 952         if (pdata->get_pendown_state) {
 953                 ts->get_pendown_state = pdata->get_pendown_state;
 954         } else if (gpio_is_valid(pdata->gpio_pendown)) {
 955
 956                 err = gpio_request_one(pdata->gpio_pendown, GPIOF_IN,
 957                                        "ads7846_pendown");
 958                 if (err) {
 959                         dev_err(&spi->dev,
 960                                 "failed to request/setup pendown GPIO%d: %d\n",
 961                                 pdata->gpio_pendown, err);
 962                         return err;
 963                 }
 964
 965                 ts->gpio_pendown = pdata->gpio_pendown;
 966
 967                 if (pdata->gpio_pendown_debounce)
 968                         gpio_set_debounce(pdata->gpio_pendown,
 969                                           pdata->gpio_pendown_debounce);
 970         } else {
 971                 dev_err(&spi->dev, "no get_pendown_state nor gpio_pendown?\n");
 972                 return -EINVAL;
 973         }
 974
 975         return 0;
 976 }
 977
 978 /*
 979  * Set up the transfers to read touchscreen state; this assumes we
 980  * use formula #2 for pressure, not #3.
 981  */
 982 static void ads7846_setup_spi_msg(struct ads7846 *ts,
 983                                   const struct ads7846_platform_data *pdata)
 984 {
 985         struct spi_message *m = &ts->msg[0];
 986         struct spi_transfer *x = ts->xfer;
 987         struct ads7846_packet *packet = ts->packet;
 988         int vref = pdata->keep_vref_on;
 989
 990         if (ts->model == 7873) {
 991                 /*
 992                  * The AD7873 is almost identical to the ADS7846
 993                  * keep VREF off during differential/ratiometric
 994                  * conversion modes.
 995                  */
 996                 ts->model = 7846;
 997                 vref = 0;
 998         }
 999
1000         ts->msg_count = 1;
1001         spi_message_init(m);
1002         m->context = ts;
1003
1004         packet->read_y_cmd.cmd = READ_Y(vref);
1005         x->tx_buf = &packet->read_y_cmd;
1006         x->rx_buf = &packet->tc.y;
1007         x->len = 3;
1008         spi_message_add_tail(x, m);
1009
1010         /*
1011          * The first sample after switching drivers can be low quality;
1012          * optionally discard it, using a second one after the signals
1013          * have had enough time to stabilize.
1014          */
1015         if (pdata->settle_delay_usecs) {
1016                 x->delay.value = pdata->settle_delay_usecs;
1017                 x->delay.unit = SPI_DELAY_UNIT_USECS;
1018                 x++;
1019
1020                 x->tx_buf = &packet->read_y_cmd;
1021                 x->rx_buf = &packet->tc.y;
1022                 x->len = 3;
1023                 spi_message_add_tail(x, m);
1024         }
1025
1026         ts->msg_count++;
1027         m++;
1028         spi_message_init(m);
1029         m->context = ts;
1030
1031         /* turn y- off, x+ on, then leave in lowpower */
1032         x++;
1033         packet->read_x_cmd.cmd = READ_X(vref);
1034         x->tx_buf = &packet->read_x_cmd;
1035         x->rx_buf = &packet->tc.x;
1036         x->len = 3;
1037         spi_message_add_tail(x, m);
1038
1039         /* ... maybe discard first sample ... */
1040         if (pdata->settle_delay_usecs) {
1041                 x->delay.value = pdata->settle_delay_usecs;
1042                 x->delay.unit = SPI_DELAY_UNIT_USECS;
1043
1044                 x++;
1045                 x->tx_buf = &packet->read_x_cmd;
1046                 x->rx_buf = &packet->tc.x;
1047                 x->len = 3;
1048                 spi_message_add_tail(x, m);
1049         }
1050
1051         /* turn y+ off, x- on; we'll use formula #2 */
1052         if (ts->model == 7846) {
1053                 ts->msg_count++;
1054                 m++;
1055                 spi_message_init(m);
1056                 m->context = ts;
1057
1058                 x++;
1059                 packet->read_z1_cmd.cmd = READ_Z1(vref);
1060                 x->tx_buf = &packet->read_z1_cmd;
1061                 x->rx_buf = &packet->tc.z1;
1062                 x->len = 3;
1063                 spi_message_add_tail(x, m);
1064
1065                 /* ... maybe discard first sample ... */
1066                 if (pdata->settle_delay_usecs) {
1067                         x->delay.value = pdata->settle_delay_usecs;
1068                         x->delay.unit = SPI_DELAY_UNIT_USECS;
1069
1070                         x++;
1071                         x->tx_buf = &packet->read_z1_cmd;
1072                         x->rx_buf = &packet->tc.z1;
1073                         x->len = 3;
1074                         spi_message_add_tail(x, m);
1075                 }
1076
1077                 ts->msg_count++;
1078                 m++;
1079                 spi_message_init(m);
1080                 m->context = ts;
1081
1082                 x++;
1083                 packet->read_z2_cmd.cmd = READ_Z2(vref);
1084                 x->tx_buf = &packet->read_z2_cmd;
1085                 x->rx_buf = &packet->tc.z2;
1086                 x->len = 3;
1087                 spi_message_add_tail(x, m);
1088
1089                 /* ... maybe discard first sample ... */
1090                 if (pdata->settle_delay_usecs) {
1091                         x->delay.value = pdata->settle_delay_usecs;
1092                         x->delay.unit = SPI_DELAY_UNIT_USECS;
1093
1094                         x++;
1095                         x->tx_buf = &packet->read_z2_cmd;
1096                         x->rx_buf = &packet->tc.z2;
1097                         x->len = 3;
1098                         spi_message_add_tail(x, m);
1099                 }
1100         }
1101
1102         /* power down */
1103         ts->msg_count++;
1104         m++;
1105         spi_message_init(m);
1106         m->context = ts;
1107
1108         x++;
1109         packet->pwrdown_cmd.cmd = PWRDOWN;
1110         x->tx_buf = &packet->pwrdown_cmd;
1111         x->len = 3;
1112
1113         CS_CHANGE(*x);
1114         spi_message_add_tail(x, m);
1115 }
1116
1117 #ifdef CONFIG_OF
1118 static const struct of_device_id ads7846_dt_ids[] = {
1119         { .compatible = "ti,tsc2046",   .data = (void *) 7846 },
1120         { .compatible = "ti,ads7843",   .data = (void *) 7843 },
1121         { .compatible = "ti,ads7845",   .data = (void *) 7845 },
1122         { .compatible = "ti,ads7846",   .data = (void *) 7846 },
1123         { .compatible = "ti,ads7873",   .data = (void *) 7873 },
1124         { }
1125 };
1126 MODULE_DEVICE_TABLE(of, ads7846_dt_ids);
1127
1128 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1129 {
1130         struct ads7846_platform_data *pdata;
1131         struct device_node *node = dev->of_node;
1132         const struct of_device_id *match;
1133         u32 value;
1134
1135         if (!node) {
1136                 dev_err(dev, "Device does not have associated DT data\n");
1137                 return ERR_PTR(-EINVAL);
1138         }
1139
1140         match = of_match_device(ads7846_dt_ids, dev);
1141         if (!match) {
1142                 dev_err(dev, "Unknown device model\n");
1143                 return ERR_PTR(-EINVAL);
1144         }
1145
1146         pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
1147         if (!pdata)
1148                 return ERR_PTR(-ENOMEM);
1149
1150         pdata->model = (unsigned long)match->data;
1151
1152         of_property_read_u16(node, "ti,vref-delay-usecs",
1153                              &pdata->vref_delay_usecs);
1154         of_property_read_u16(node, "ti,vref-mv", &pdata->vref_mv);
1155         pdata->keep_vref_on = of_property_read_bool(node, "ti,keep-vref-on");
1156
1157         pdata->swap_xy = of_property_read_bool(node, "ti,swap-xy");
1158
1159         of_property_read_u16(node, "ti,settle-delay-usec",
1160                              &pdata->settle_delay_usecs);
1161         of_property_read_u16(node, "ti,penirq-recheck-delay-usecs",
1162                              &pdata->penirq_recheck_delay_usecs);
1163
1164         of_property_read_u16(node, "ti,x-plate-ohms", &pdata->x_plate_ohms);
1165         of_property_read_u16(node, "ti,y-plate-ohms", &pdata->y_plate_ohms);
1166
1167         of_property_read_u16(node, "ti,x-min", &pdata->x_min);
1168         of_property_read_u16(node, "ti,y-min", &pdata->y_min);
1169         of_property_read_u16(node, "ti,x-max", &pdata->x_max);
1170         of_property_read_u16(node, "ti,y-max", &pdata->y_max);
1171
1172         /*
1173          * touchscreen-max-pressure gets parsed during
1174          * touchscreen_parse_properties()
1175          */
1176         of_property_read_u16(node, "ti,pressure-min", &pdata->pressure_min);
1177         if (!of_property_read_u32(node, "touchscreen-min-pressure", &value))
1178                 pdata->pressure_min = (u16) value;
1179         of_property_read_u16(node, "ti,pressure-max", &pdata->pressure_max);
1180
1181         of_property_read_u16(node, "ti,debounce-max", &pdata->debounce_max);
1182         if (!of_property_read_u32(node, "touchscreen-average-samples", &value))
1183                 pdata->debounce_max = (u16) value;
1184         of_property_read_u16(node, "ti,debounce-tol", &pdata->debounce_tol);
1185         of_property_read_u16(node, "ti,debounce-rep", &pdata->debounce_rep);
1186
1187         of_property_read_u32(node, "ti,pendown-gpio-debounce",
1188                              &pdata->gpio_pendown_debounce);
1189
1190         pdata->wakeup = of_property_read_bool(node, "wakeup-source") ||
1191                         of_property_read_bool(node, "linux,wakeup");
1192
1193         pdata->gpio_pendown = of_get_named_gpio(dev->of_node, "pendown-gpio", 0);
1194
1195         return pdata;
1196 }
1197 #else
1198 static const struct ads7846_platform_data *ads7846_probe_dt(struct device *dev)
1199 {
1200         dev_err(dev, "no platform data defined\n");
1201         return ERR_PTR(-EINVAL);
1202 }
1203 #endif
1204
1205 static int ads7846_probe(struct spi_device *spi)
1206 {
1207         const struct ads7846_platform_data *pdata;
1208         struct ads7846 *ts;
1209         struct ads7846_packet *packet;
1210         struct input_dev *input_dev;
1211         unsigned long irq_flags;
1212         int err;
1213
1214         if (!spi->irq) {
1215                 dev_dbg(&spi->dev, "no IRQ?\n");
1216                 return -EINVAL;
1217         }
1218
1219         /* don't exceed max specified sample rate */
1220         if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
1221                 dev_err(&spi->dev, "f(sample) %d KHz?\n",
1222                                 (spi->max_speed_hz/SAMPLE_BITS)/1000);
1223                 return -EINVAL;
1224         }
1225
1226         /*
1227          * We'd set TX word size 8 bits and RX word size to 13 bits ... except
1228          * that even if the hardware can do that, the SPI controller driver
1229          * may not.  So we stick to very-portable 8 bit words, both RX and TX.
1230          */
1231         spi->bits_per_word = 8;
1232         spi->mode &= ~SPI_MODE_X_MASK;
1233         spi->mode |= SPI_MODE_0;
1234         err = spi_setup(spi);
1235         if (err < 0)
1236                 return err;
1237
1238         ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
1239         packet = kzalloc(sizeof(struct ads7846_packet), GFP_KERNEL);
1240         input_dev = input_allocate_device();
1241         if (!ts || !packet || !input_dev) {
1242                 err = -ENOMEM;
1243                 goto err_free_mem;
1244         }
1245
1246         spi_set_drvdata(spi, ts);
1247
1248         ts->packet = packet;
1249         ts->spi = spi;
1250         ts->input = input_dev;
1251
1252         mutex_init(&ts->lock);
1253         init_waitqueue_head(&ts->wait);
1254
1255         pdata = dev_get_platdata(&spi->dev);
1256         if (!pdata) {
1257                 pdata = ads7846_probe_dt(&spi->dev);
1258                 if (IS_ERR(pdata)) {
1259                         err = PTR_ERR(pdata);
1260                         goto err_free_mem;
1261                 }
1262         }
1263
1264         ts->model = pdata->model ? : 7846;
1265         ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
1266         ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
1267         ts->vref_mv = pdata->vref_mv;
1268
1269         if (pdata->filter != NULL) {
1270                 if (pdata->filter_init != NULL) {
1271                         err = pdata->filter_init(pdata, &ts->filter_data);
1272                         if (err < 0)
1273                                 goto err_free_mem;
1274                 }
1275                 ts->filter = pdata->filter;
1276                 ts->filter_cleanup = pdata->filter_cleanup;
1277         } else if (pdata->debounce_max) {
1278                 ts->debounce_max = pdata->debounce_max;
1279                 if (ts->debounce_max < 2)
1280                         ts->debounce_max = 2;
1281                 ts->debounce_tol = pdata->debounce_tol;
1282                 ts->debounce_rep = pdata->debounce_rep;
1283                 ts->filter = ads7846_debounce_filter;
1284                 ts->filter_data = ts;
1285         } else {
1286                 ts->filter = ads7846_no_filter;
1287         }
1288
1289         err = ads7846_setup_pendown(spi, ts, pdata);
1290         if (err)
1291                 goto err_cleanup_filter;
1292
1293         if (pdata->penirq_recheck_delay_usecs)
1294                 ts->penirq_recheck_delay_usecs =
1295                                 pdata->penirq_recheck_delay_usecs;
1296
1297         ts->wait_for_sync = pdata->wait_for_sync ? : null_wait_for_sync;
1298
1299         snprintf(ts->phys, sizeof(ts->phys), "%s/input0", dev_name(&spi->dev));
1300         snprintf(ts->name, sizeof(ts->name), "ADS%d Touchscreen", ts->model);
1301
1302         input_dev->name = ts->name;
1303         input_dev->phys = ts->phys;
1304         input_dev->dev.parent = &spi->dev;
1305
1306         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
1307         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
1308         input_set_abs_params(input_dev, ABS_X,
1309                         pdata->x_min ? : 0,
1310                         pdata->x_max ? : MAX_12BIT,
1311                         0, 0);
1312         input_set_abs_params(input_dev, ABS_Y,
1313                         pdata->y_min ? : 0,
1314                         pdata->y_max ? : MAX_12BIT,
1315                         0, 0);
1316         input_set_abs_params(input_dev, ABS_PRESSURE,
1317                         pdata->pressure_min, pdata->pressure_max, 0, 0);
1318
1319         /*
1320          * Parse common framework properties. Must be done here to ensure the
1321          * correct behaviour in case of using the legacy vendor bindings. The
1322          * general binding value overrides the vendor specific one.
1323          */
1324         touchscreen_parse_properties(ts->input, false, &ts->core_prop);
1325         ts->pressure_max = input_abs_get_max(input_dev, ABS_PRESSURE) ? : ~0;
1326
1327         /*
1328          * Check if legacy ti,swap-xy binding is used instead of
1329          * touchscreen-swapped-x-y
1330          */
1331         if (!ts->core_prop.swap_x_y && pdata->swap_xy) {
1332                 swap(input_dev->absinfo[ABS_X], input_dev->absinfo[ABS_Y]);
1333                 ts->core_prop.swap_x_y = true;
1334         }
1335
1336         ads7846_setup_spi_msg(ts, pdata);
1337
1338         ts->reg = regulator_get(&spi->dev, "vcc");
1339         if (IS_ERR(ts->reg)) {
1340                 err = PTR_ERR(ts->reg);
1341                 dev_err(&spi->dev, "unable to get regulator: %d\n", err);
1342                 goto err_free_gpio;
1343         }
1344
1345         err = regulator_enable(ts->reg);
1346         if (err) {
1347                 dev_err(&spi->dev, "unable to enable regulator: %d\n", err);
1348                 goto err_put_regulator;
1349         }
1350
1351         irq_flags = pdata->irq_flags ? : IRQF_TRIGGER_FALLING;
1352         irq_flags |= IRQF_ONESHOT;
1353
1354         err = request_threaded_irq(spi->irq, ads7846_hard_irq, ads7846_irq,
1355                                    irq_flags, spi->dev.driver->name, ts);
1356         if (err && !pdata->irq_flags) {
1357                 dev_info(&spi->dev,
1358                         "trying pin change workaround on irq %d\n", spi->irq);
1359                 irq_flags |= IRQF_TRIGGER_RISING;
1360                 err = request_threaded_irq(spi->irq,
1361                                   ads7846_hard_irq, ads7846_irq,
1362                                   irq_flags, spi->dev.driver->name, ts);
1363         }
1364
1365         if (err) {
1366                 dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
1367                 goto err_disable_regulator;
1368         }
1369
1370         err = ads784x_hwmon_register(spi, ts);
1371         if (err)
1372                 goto err_free_irq;
1373
1374         dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
1375
1376         /*
1377          * Take a first sample, leaving nPENIRQ active and vREF off; avoid
1378          * the touchscreen, in case it's not connected.
1379          */
1380         if (ts->model == 7845)
1381                 ads7845_read12_ser(&spi->dev, PWRDOWN);
1382         else
1383                 (void) ads7846_read12_ser(&spi->dev, READ_12BIT_SER(vaux));
1384
1385         err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
1386         if (err)
1387                 goto err_remove_hwmon;
1388
1389         err = input_register_device(input_dev);
1390         if (err)
1391                 goto err_remove_attr_group;
1392
1393         device_init_wakeup(&spi->dev, pdata->wakeup);
1394
1395         /*
1396          * If device does not carry platform data we must have allocated it
1397          * when parsing DT data.
1398          */
1399         if (!dev_get_platdata(&spi->dev))
1400                 devm_kfree(&spi->dev, (void *)pdata);
1401
1402         return 0;
1403
1404  err_remove_attr_group:
1405         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1406  err_remove_hwmon:
1407         ads784x_hwmon_unregister(spi, ts);
1408  err_free_irq:
1409         free_irq(spi->irq, ts);
1410  err_disable_regulator:
1411         regulator_disable(ts->reg);
1412  err_put_regulator:
1413         regulator_put(ts->reg);
1414  err_free_gpio:
1415         if (!ts->get_pendown_state)
1416                 gpio_free(ts->gpio_pendown);
1417  err_cleanup_filter:
1418         if (ts->filter_cleanup)
1419                 ts->filter_cleanup(ts->filter_data);
1420  err_free_mem:
1421         input_free_device(input_dev);
1422         kfree(packet);
1423         kfree(ts);
1424         return err;
1425 }
1426
1427 static int ads7846_remove(struct spi_device *spi)
1428 {
1429         struct ads7846 *ts = spi_get_drvdata(spi);
1430
1431         sysfs_remove_group(&spi->dev.kobj, &ads784x_attr_group);
1432
1433         ads7846_disable(ts);
1434         free_irq(ts->spi->irq, ts);
1435
1436         input_unregister_device(ts->input);
1437
1438         ads784x_hwmon_unregister(spi, ts);
1439
1440         regulator_put(ts->reg);
1441
1442         if (!ts->get_pendown_state) {
1443                 /*
1444                  * If we are not using specialized pendown method we must
1445                  * have been relying on gpio we set up ourselves.
1446                  */
1447                 gpio_free(ts->gpio_pendown);
1448         }
1449
1450         if (ts->filter_cleanup)
1451                 ts->filter_cleanup(ts->filter_data);
1452
1453         kfree(ts->packet);
1454         kfree(ts);
1455
1456         dev_dbg(&spi->dev, "unregistered touchscreen\n");
1457
1458         return 0;
1459 }
1460
1461 static struct spi_driver ads7846_driver = {
1462         .driver = {
1463                 .name   = "ads7846",
1464                 .pm     = &ads7846_pm,
1465                 .of_match_table = of_match_ptr(ads7846_dt_ids),
1466         },
1467         .probe          = ads7846_probe,
1468         .remove         = ads7846_remove,
1469 };
1470
1471 module_spi_driver(ads7846_driver);
1472
1473 MODULE_DESCRIPTION("ADS7846 TouchScreen Driver");
1474 MODULE_LICENSE("GPL");
1475 MODULE_ALIAS("spi:ads7846");