drivers/input/keyboard/imx_keypad.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Driver for the IMX keypad port.
   4 // Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
   5
   6 #include <linux/clk.h>
   7 #include <linux/delay.h>
   8 #include <linux/device.h>
   9 #include <linux/err.h>
  10 #include <linux/input/matrix_keypad.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/io.h>
  13 #include <linux/jiffies.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/slab.h>
  19 #include <linux/timer.h>
  20
  21 /*
  22  * Keypad Controller registers (halfword)
  23  */
  24 #define KPCR            0x00 /* Keypad Control Register */
  25
  26 #define KPSR            0x02 /* Keypad Status Register */
  27 #define KBD_STAT_KPKD   (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */
  28 #define KBD_STAT_KPKR   (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */
  29 #define KBD_STAT_KDSC   (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/
  30 #define KBD_STAT_KRSS   (0x1 << 3) /* Key Release Synch Status bit (w1c)*/
  31 #define KBD_STAT_KDIE   (0x1 << 8) /* Key Depress Interrupt Enable Status bit */
  32 #define KBD_STAT_KRIE   (0x1 << 9) /* Key Release Interrupt Enable */
  33 #define KBD_STAT_KPPEN  (0x1 << 10) /* Keypad Clock Enable */
  34
  35 #define KDDR            0x04 /* Keypad Data Direction Register */
  36 #define KPDR            0x06 /* Keypad Data Register */
  37
  38 #define MAX_MATRIX_KEY_ROWS     8
  39 #define MAX_MATRIX_KEY_COLS     8
  40 #define MATRIX_ROW_SHIFT        3
  41
  42 #define MAX_MATRIX_KEY_NUM      (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS)
  43
  44 struct imx_keypad {
  45
  46         struct clk *clk;
  47         struct input_dev *input_dev;
  48         void __iomem *mmio_base;
  49
  50         int                     irq;
  51         struct timer_list       check_matrix_timer;
  52
  53         /*
  54          * The matrix is stable only if no changes are detected after
  55          * IMX_KEYPAD_SCANS_FOR_STABILITY scans
  56          */
  57 #define IMX_KEYPAD_SCANS_FOR_STABILITY 3
  58         int                     stable_count;
  59
  60         bool                    enabled;
  61
  62         /* Masks for enabled rows/cols */
  63         unsigned short          rows_en_mask;
  64         unsigned short          cols_en_mask;
  65
  66         unsigned short          keycodes[MAX_MATRIX_KEY_NUM];
  67
  68         /*
  69          * Matrix states:
  70          * -stable: achieved after a complete debounce process.
  71          * -unstable: used in the debouncing process.
  72          */
  73         unsigned short          matrix_stable_state[MAX_MATRIX_KEY_COLS];
  74         unsigned short          matrix_unstable_state[MAX_MATRIX_KEY_COLS];
  75 };
  76
  77 /* Scan the matrix and return the new state in *matrix_volatile_state. */
  78 static void imx_keypad_scan_matrix(struct imx_keypad *keypad,
  79                                   unsigned short *matrix_volatile_state)
  80 {
  81         int col;
  82         unsigned short reg_val;
  83
  84         for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
  85                 if ((keypad->cols_en_mask & (1 << col)) == 0)
  86                         continue;
  87                 /*
  88                  * Discharge keypad capacitance:
  89                  * 2. write 1s on column data.
  90                  * 3. configure columns as totem-pole to discharge capacitance.
  91                  * 4. configure columns as open-drain.
  92                  */
  93                 reg_val = readw(keypad->mmio_base + KPDR);
  94                 reg_val |= 0xff00;
  95                 writew(reg_val, keypad->mmio_base + KPDR);
  96
  97                 reg_val = readw(keypad->mmio_base + KPCR);
  98                 reg_val &= ~((keypad->cols_en_mask & 0xff) << 8);
  99                 writew(reg_val, keypad->mmio_base + KPCR);
 100
 101                 udelay(2);
 102
 103                 reg_val = readw(keypad->mmio_base + KPCR);
 104                 reg_val |= (keypad->cols_en_mask & 0xff) << 8;
 105                 writew(reg_val, keypad->mmio_base + KPCR);
 106
 107                 /*
 108                  * 5. Write a single column to 0, others to 1.
 109                  * 6. Sample row inputs and save data.
 110                  * 7. Repeat steps 2 - 6 for remaining columns.
 111                  */
 112                 reg_val = readw(keypad->mmio_base + KPDR);
 113                 reg_val &= ~(1 << (8 + col));
 114                 writew(reg_val, keypad->mmio_base + KPDR);
 115
 116                 /*
 117                  * Delay added to avoid propagating the 0 from column to row
 118                  * when scanning.
 119                  */
 120                 udelay(5);
 121
 122                 /*
 123                  * 1s in matrix_volatile_state[col] means key pressures
 124                  * throw data from non enabled rows.
 125                  */
 126                 reg_val = readw(keypad->mmio_base + KPDR);
 127                 matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask;
 128         }
 129
 130         /*
 131          * Return in standby mode:
 132          * 9. write 0s to columns
 133          */
 134         reg_val = readw(keypad->mmio_base + KPDR);
 135         reg_val &= 0x00ff;
 136         writew(reg_val, keypad->mmio_base + KPDR);
 137 }
 138
 139 /*
 140  * Compare the new matrix state (volatile) with the stable one stored in
 141  * keypad->matrix_stable_state and fire events if changes are detected.
 142  */
 143 static void imx_keypad_fire_events(struct imx_keypad *keypad,
 144                                    unsigned short *matrix_volatile_state)
 145 {
 146         struct input_dev *input_dev = keypad->input_dev;
 147         int row, col;
 148
 149         for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
 150                 unsigned short bits_changed;
 151                 int code;
 152
 153                 if ((keypad->cols_en_mask & (1 << col)) == 0)
 154                         continue; /* Column is not enabled */
 155
 156                 bits_changed = keypad->matrix_stable_state[col] ^
 157                                                 matrix_volatile_state[col];
 158
 159                 if (bits_changed == 0)
 160                         continue; /* Column does not contain changes */
 161
 162                 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
 163                         if ((keypad->rows_en_mask & (1 << row)) == 0)
 164                                 continue; /* Row is not enabled */
 165                         if ((bits_changed & (1 << row)) == 0)
 166                                 continue; /* Row does not contain changes */
 167
 168                         code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
 169                         input_event(input_dev, EV_MSC, MSC_SCAN, code);
 170                         input_report_key(input_dev, keypad->keycodes[code],
 171                                 matrix_volatile_state[col] & (1 << row));
 172                         dev_dbg(&input_dev->dev, "Event code: %d, val: %d",
 173                                 keypad->keycodes[code],
 174                                 matrix_volatile_state[col] & (1 << row));
 175                 }
 176         }
 177         input_sync(input_dev);
 178 }
 179
 180 /*
 181  * imx_keypad_check_for_events is the timer handler.
 182  */
 183 static void imx_keypad_check_for_events(struct timer_list *t)
 184 {
 185         struct imx_keypad *keypad = from_timer(keypad, t, check_matrix_timer);
 186         unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS];
 187         unsigned short reg_val;
 188         bool state_changed, is_zero_matrix;
 189         int i;
 190
 191         memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state));
 192
 193         imx_keypad_scan_matrix(keypad, matrix_volatile_state);
 194
 195         state_changed = false;
 196         for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
 197                 if ((keypad->cols_en_mask & (1 << i)) == 0)
 198                         continue;
 199
 200                 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) {
 201                         state_changed = true;
 202                         break;
 203                 }
 204         }
 205
 206         /*
 207          * If the matrix state is changed from the previous scan
 208          *   (Re)Begin the debouncing process, saving the new state in
 209          *    keypad->matrix_unstable_state.
 210          * else
 211          *   Increase the count of number of scans with a stable state.
 212          */
 213         if (state_changed) {
 214                 memcpy(keypad->matrix_unstable_state, matrix_volatile_state,
 215                         sizeof(matrix_volatile_state));
 216                 keypad->stable_count = 0;
 217         } else
 218                 keypad->stable_count++;
 219
 220         /*
 221          * If the matrix is not as stable as we want reschedule scan
 222          * in the near future.
 223          */
 224         if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) {
 225                 mod_timer(&keypad->check_matrix_timer,
 226                           jiffies + msecs_to_jiffies(10));
 227                 return;
 228         }
 229
 230         /*
 231          * If the matrix state is stable, fire the events and save the new
 232          * stable state. Note, if the matrix is kept stable for longer
 233          * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all
 234          * events have already been generated.
 235          */
 236         if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) {
 237                 imx_keypad_fire_events(keypad, matrix_volatile_state);
 238
 239                 memcpy(keypad->matrix_stable_state, matrix_volatile_state,
 240                         sizeof(matrix_volatile_state));
 241         }
 242
 243         is_zero_matrix = true;
 244         for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
 245                 if (matrix_volatile_state[i] != 0) {
 246                         is_zero_matrix = false;
 247                         break;
 248                 }
 249         }
 250
 251
 252         if (is_zero_matrix) {
 253                 /*
 254                  * All keys have been released. Enable only the KDI
 255                  * interrupt for future key presses (clear the KDI
 256                  * status bit and its sync chain before that).
 257                  */
 258                 reg_val = readw(keypad->mmio_base + KPSR);
 259                 reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC;
 260                 writew(reg_val, keypad->mmio_base + KPSR);
 261
 262                 reg_val = readw(keypad->mmio_base + KPSR);
 263                 reg_val |= KBD_STAT_KDIE;
 264                 reg_val &= ~KBD_STAT_KRIE;
 265                 writew(reg_val, keypad->mmio_base + KPSR);
 266         } else {
 267                 /*
 268                  * Some keys are still pressed. Schedule a rescan in
 269                  * attempt to detect multiple key presses and enable
 270                  * the KRI interrupt to react quickly to key release
 271                  * event.
 272                  */
 273                 mod_timer(&keypad->check_matrix_timer,
 274                           jiffies + msecs_to_jiffies(60));
 275
 276                 reg_val = readw(keypad->mmio_base + KPSR);
 277                 reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS;
 278                 writew(reg_val, keypad->mmio_base + KPSR);
 279
 280                 reg_val = readw(keypad->mmio_base + KPSR);
 281                 reg_val |= KBD_STAT_KRIE;
 282                 reg_val &= ~KBD_STAT_KDIE;
 283                 writew(reg_val, keypad->mmio_base + KPSR);
 284         }
 285 }
 286
 287 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id)
 288 {
 289         struct imx_keypad *keypad = dev_id;
 290         unsigned short reg_val;
 291
 292         reg_val = readw(keypad->mmio_base + KPSR);
 293
 294         /* Disable both interrupt types */
 295         reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
 296         /* Clear interrupts status bits */
 297         reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
 298         writew(reg_val, keypad->mmio_base + KPSR);
 299
 300         if (keypad->enabled) {
 301                 /* The matrix is supposed to be changed */
 302                 keypad->stable_count = 0;
 303
 304                 /* Schedule the scanning procedure near in the future */
 305                 mod_timer(&keypad->check_matrix_timer,
 306                           jiffies + msecs_to_jiffies(2));
 307         }
 308
 309         return IRQ_HANDLED;
 310 }
 311
 312 static void imx_keypad_config(struct imx_keypad *keypad)
 313 {
 314         unsigned short reg_val;
 315
 316         /*
 317          * Include enabled rows in interrupt generation (KPCR[7:0])
 318          * Configure keypad columns as open-drain (KPCR[15:8])
 319          */
 320         reg_val = readw(keypad->mmio_base + KPCR);
 321         reg_val |= keypad->rows_en_mask & 0xff;         /* rows */
 322         reg_val |= (keypad->cols_en_mask & 0xff) << 8;  /* cols */
 323         writew(reg_val, keypad->mmio_base + KPCR);
 324
 325         /* Write 0's to KPDR[15:8] (Colums) */
 326         reg_val = readw(keypad->mmio_base + KPDR);
 327         reg_val &= 0x00ff;
 328         writew(reg_val, keypad->mmio_base + KPDR);
 329
 330         /* Configure columns as output, rows as input (KDDR[15:0]) */
 331         writew(0xff00, keypad->mmio_base + KDDR);
 332
 333         /*
 334          * Clear Key Depress and Key Release status bit.
 335          * Clear both synchronizer chain.
 336          */
 337         reg_val = readw(keypad->mmio_base + KPSR);
 338         reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD |
 339                    KBD_STAT_KDSC | KBD_STAT_KRSS;
 340         writew(reg_val, keypad->mmio_base + KPSR);
 341
 342         /* Enable KDI and disable KRI (avoid false release events). */
 343         reg_val |= KBD_STAT_KDIE;
 344         reg_val &= ~KBD_STAT_KRIE;
 345         writew(reg_val, keypad->mmio_base + KPSR);
 346 }
 347
 348 static void imx_keypad_inhibit(struct imx_keypad *keypad)
 349 {
 350         unsigned short reg_val;
 351
 352         /* Inhibit KDI and KRI interrupts. */
 353         reg_val = readw(keypad->mmio_base + KPSR);
 354         reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
 355         reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
 356         writew(reg_val, keypad->mmio_base + KPSR);
 357
 358         /* Colums as open drain and disable all rows */
 359         reg_val = (keypad->cols_en_mask & 0xff) << 8;
 360         writew(reg_val, keypad->mmio_base + KPCR);
 361 }
 362
 363 static void imx_keypad_close(struct input_dev *dev)
 364 {
 365         struct imx_keypad *keypad = input_get_drvdata(dev);
 366
 367         dev_dbg(&dev->dev, ">%s\n", __func__);
 368
 369         /* Mark keypad as being inactive */
 370         keypad->enabled = false;
 371         synchronize_irq(keypad->irq);
 372         del_timer_sync(&keypad->check_matrix_timer);
 373
 374         imx_keypad_inhibit(keypad);
 375
 376         /* Disable clock unit */
 377         clk_disable_unprepare(keypad->clk);
 378 }
 379
 380 static int imx_keypad_open(struct input_dev *dev)
 381 {
 382         struct imx_keypad *keypad = input_get_drvdata(dev);
 383         int error;
 384
 385         dev_dbg(&dev->dev, ">%s\n", __func__);
 386
 387         /* Enable the kpp clock */
 388         error = clk_prepare_enable(keypad->clk);
 389         if (error)
 390                 return error;
 391
 392         /* We became active from now */
 393         keypad->enabled = true;
 394
 395         imx_keypad_config(keypad);
 396
 397         /* Sanity control, not all the rows must be actived now. */
 398         if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) {
 399                 dev_err(&dev->dev,
 400                         "too many keys pressed, control pins initialisation\n");
 401                 goto open_err;
 402         }
 403
 404         return 0;
 405
 406 open_err:
 407         imx_keypad_close(dev);
 408         return -EIO;
 409 }
 410
 411 #ifdef CONFIG_OF
 412 static const struct of_device_id imx_keypad_of_match[] = {
 413         { .compatible = "fsl,imx21-kpp", },
 414         { /* sentinel */ }
 415 };
 416 MODULE_DEVICE_TABLE(of, imx_keypad_of_match);
 417 #endif
 418
 419 static int imx_keypad_probe(struct platform_device *pdev)
 420 {
 421         const struct matrix_keymap_data *keymap_data =
 422                         dev_get_platdata(&pdev->dev);
 423         struct imx_keypad *keypad;
 424         struct input_dev *input_dev;
 425         int irq, error, i, row, col;
 426
 427         if (!keymap_data && !pdev->dev.of_node) {
 428                 dev_err(&pdev->dev, "no keymap defined\n");
 429                 return -EINVAL;
 430         }
 431
 432         irq = platform_get_irq(pdev, 0);
 433         if (irq < 0) {
 434                 dev_err(&pdev->dev, "no irq defined in platform data\n");
 435                 return irq;
 436         }
 437
 438         input_dev = devm_input_allocate_device(&pdev->dev);
 439         if (!input_dev) {
 440                 dev_err(&pdev->dev, "failed to allocate the input device\n");
 441                 return -ENOMEM;
 442         }
 443
 444         keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
 445         if (!keypad) {
 446                 dev_err(&pdev->dev, "not enough memory for driver data\n");
 447                 return -ENOMEM;
 448         }
 449
 450         keypad->input_dev = input_dev;
 451         keypad->irq = irq;
 452         keypad->stable_count = 0;
 453
 454         timer_setup(&keypad->check_matrix_timer,
 455                     imx_keypad_check_for_events, 0);
 456
 457         keypad->mmio_base = devm_platform_ioremap_resource(pdev, 0);
 458         if (IS_ERR(keypad->mmio_base))
 459                 return PTR_ERR(keypad->mmio_base);
 460
 461         keypad->clk = devm_clk_get(&pdev->dev, NULL);
 462         if (IS_ERR(keypad->clk)) {
 463                 dev_err(&pdev->dev, "failed to get keypad clock\n");
 464                 return PTR_ERR(keypad->clk);
 465         }
 466
 467         /* Init the Input device */
 468         input_dev->name = pdev->name;
 469         input_dev->id.bustype = BUS_HOST;
 470         input_dev->dev.parent = &pdev->dev;
 471         input_dev->open = imx_keypad_open;
 472         input_dev->close = imx_keypad_close;
 473
 474         error = matrix_keypad_build_keymap(keymap_data, NULL,
 475                                            MAX_MATRIX_KEY_ROWS,
 476                                            MAX_MATRIX_KEY_COLS,
 477                                            keypad->keycodes, input_dev);
 478         if (error) {
 479                 dev_err(&pdev->dev, "failed to build keymap\n");
 480                 return error;
 481         }
 482
 483         /* Search for rows and cols enabled */
 484         for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
 485                 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
 486                         i = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
 487                         if (keypad->keycodes[i] != KEY_RESERVED) {
 488                                 keypad->rows_en_mask |= 1 << row;
 489                                 keypad->cols_en_mask |= 1 << col;
 490                         }
 491                 }
 492         }
 493         dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask);
 494         dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask);
 495
 496         __set_bit(EV_REP, input_dev->evbit);
 497         input_set_capability(input_dev, EV_MSC, MSC_SCAN);
 498         input_set_drvdata(input_dev, keypad);
 499
 500         /* Ensure that the keypad will stay dormant until opened */
 501         error = clk_prepare_enable(keypad->clk);
 502         if (error)
 503                 return error;
 504         imx_keypad_inhibit(keypad);
 505         clk_disable_unprepare(keypad->clk);
 506
 507         error = devm_request_irq(&pdev->dev, irq, imx_keypad_irq_handler, 0,
 508                             pdev->name, keypad);
 509         if (error) {
 510                 dev_err(&pdev->dev, "failed to request IRQ\n");
 511                 return error;
 512         }
 513
 514         /* Register the input device */
 515         error = input_register_device(input_dev);
 516         if (error) {
 517                 dev_err(&pdev->dev, "failed to register input device\n");
 518                 return error;
 519         }
 520
 521         platform_set_drvdata(pdev, keypad);
 522         device_init_wakeup(&pdev->dev, 1);
 523
 524         return 0;
 525 }
 526
 527 static int __maybe_unused imx_kbd_suspend(struct device *dev)
 528 {
 529         struct platform_device *pdev = to_platform_device(dev);
 530         struct imx_keypad *kbd = platform_get_drvdata(pdev);
 531         struct input_dev *input_dev = kbd->input_dev;
 532
 533         /* imx kbd can wake up system even clock is disabled */
 534         mutex_lock(&input_dev->mutex);
 535
 536         if (input_dev->users)
 537                 clk_disable_unprepare(kbd->clk);
 538
 539         mutex_unlock(&input_dev->mutex);
 540
 541         if (device_may_wakeup(&pdev->dev))
 542                 enable_irq_wake(kbd->irq);
 543
 544         return 0;
 545 }
 546
 547 static int __maybe_unused imx_kbd_resume(struct device *dev)
 548 {
 549         struct platform_device *pdev = to_platform_device(dev);
 550         struct imx_keypad *kbd = platform_get_drvdata(pdev);
 551         struct input_dev *input_dev = kbd->input_dev;
 552         int ret = 0;
 553
 554         if (device_may_wakeup(&pdev->dev))
 555                 disable_irq_wake(kbd->irq);
 556
 557         mutex_lock(&input_dev->mutex);
 558
 559         if (input_dev->users) {
 560                 ret = clk_prepare_enable(kbd->clk);
 561                 if (ret)
 562                         goto err_clk;
 563         }
 564
 565 err_clk:
 566         mutex_unlock(&input_dev->mutex);
 567
 568         return ret;
 569 }
 570
 571 static SIMPLE_DEV_PM_OPS(imx_kbd_pm_ops, imx_kbd_suspend, imx_kbd_resume);
 572
 573 static struct platform_driver imx_keypad_driver = {
 574         .driver         = {
 575                 .name   = "imx-keypad",
 576                 .pm     = &imx_kbd_pm_ops,
 577                 .of_match_table = of_match_ptr(imx_keypad_of_match),
 578         },
 579         .probe          = imx_keypad_probe,
 580 };
 581 module_platform_driver(imx_keypad_driver);
 582
 583 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
 584 MODULE_DESCRIPTION("IMX Keypad Port Driver");
 585 MODULE_LICENSE("GPL v2");
 586 MODULE_ALIAS("platform:imx-keypad");