1 /* 2 * Driver for the IMX keypad port. 3 * Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation. 8 * 9 * <<Power management needs to be implemented>>. 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/delay.h> 14 #include <linux/device.h> 15 #include <linux/err.h> 16 #include <linux/init.h> 17 #include <linux/input/matrix_keypad.h> 18 #include <linux/interrupt.h> 19 #include <linux/io.h> 20 #include <linux/jiffies.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/platform_device.h> 24 #include <linux/slab.h> 25 #include <linux/timer.h> 26 27 /* 28 * Keypad Controller registers (halfword) 29 */ 30 #define KPCR 0x00 /* Keypad Control Register */ 31 32 #define KPSR 0x02 /* Keypad Status Register */ 33 #define KBD_STAT_KPKD (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */ 34 #define KBD_STAT_KPKR (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */ 35 #define KBD_STAT_KDSC (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/ 36 #define KBD_STAT_KRSS (0x1 << 3) /* Key Release Synch Status bit (w1c)*/ 37 #define KBD_STAT_KDIE (0x1 << 8) /* Key Depress Interrupt Enable Status bit */ 38 #define KBD_STAT_KRIE (0x1 << 9) /* Key Release Interrupt Enable */ 39 #define KBD_STAT_KPPEN (0x1 << 10) /* Keypad Clock Enable */ 40 41 #define KDDR 0x04 /* Keypad Data Direction Register */ 42 #define KPDR 0x06 /* Keypad Data Register */ 43 44 #define MAX_MATRIX_KEY_ROWS 8 45 #define MAX_MATRIX_KEY_COLS 8 46 #define MATRIX_ROW_SHIFT 3 47 48 #define MAX_MATRIX_KEY_NUM (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS) 49 50 struct imx_keypad { 51 52 struct clk *clk; 53 struct input_dev *input_dev; 54 void __iomem *mmio_base; 55 56 int irq; 57 struct timer_list check_matrix_timer; 58 59 /* 60 * The matrix is stable only if no changes are detected after 61 * IMX_KEYPAD_SCANS_FOR_STABILITY scans 62 */ 63 #define IMX_KEYPAD_SCANS_FOR_STABILITY 3 64 int stable_count; 65 66 bool enabled; 67 68 /* Masks for enabled rows/cols */ 69 unsigned short rows_en_mask; 70 unsigned short cols_en_mask; 71 72 unsigned short keycodes[MAX_MATRIX_KEY_NUM]; 73 74 /* 75 * Matrix states: 76 * -stable: achieved after a complete debounce process. 77 * -unstable: used in the debouncing process. 78 */ 79 unsigned short matrix_stable_state[MAX_MATRIX_KEY_COLS]; 80 unsigned short matrix_unstable_state[MAX_MATRIX_KEY_COLS]; 81 }; 82 83 /* Scan the matrix and return the new state in *matrix_volatile_state. */ 84 static void imx_keypad_scan_matrix(struct imx_keypad *keypad, 85 unsigned short *matrix_volatile_state) 86 { 87 int col; 88 unsigned short reg_val; 89 90 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 91 if ((keypad->cols_en_mask & (1 << col)) == 0) 92 continue; 93 /* 94 * Discharge keypad capacitance: 95 * 2. write 1s on column data. 96 * 3. configure columns as totem-pole to discharge capacitance. 97 * 4. configure columns as open-drain. 98 */ 99 reg_val = readw(keypad->mmio_base + KPDR); 100 reg_val |= 0xff00; 101 writew(reg_val, keypad->mmio_base + KPDR); 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 udelay(2); 108 109 reg_val = readw(keypad->mmio_base + KPCR); 110 reg_val |= (keypad->cols_en_mask & 0xff) << 8; 111 writew(reg_val, keypad->mmio_base + KPCR); 112 113 /* 114 * 5. Write a single column to 0, others to 1. 115 * 6. Sample row inputs and save data. 116 * 7. Repeat steps 2 - 6 for remaining columns. 117 */ 118 reg_val = readw(keypad->mmio_base + KPDR); 119 reg_val &= ~(1 << (8 + col)); 120 writew(reg_val, keypad->mmio_base + KPDR); 121 122 /* 123 * Delay added to avoid propagating the 0 from column to row 124 * when scanning. 125 */ 126 udelay(5); 127 128 /* 129 * 1s in matrix_volatile_state[col] means key pressures 130 * throw data from non enabled rows. 131 */ 132 reg_val = readw(keypad->mmio_base + KPDR); 133 matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask; 134 } 135 136 /* 137 * Return in standby mode: 138 * 9. write 0s to columns 139 */ 140 reg_val = readw(keypad->mmio_base + KPDR); 141 reg_val &= 0x00ff; 142 writew(reg_val, keypad->mmio_base + KPDR); 143 } 144 145 /* 146 * Compare the new matrix state (volatile) with the stable one stored in 147 * keypad->matrix_stable_state and fire events if changes are detected. 148 */ 149 static void imx_keypad_fire_events(struct imx_keypad *keypad, 150 unsigned short *matrix_volatile_state) 151 { 152 struct input_dev *input_dev = keypad->input_dev; 153 int row, col; 154 155 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 156 unsigned short bits_changed; 157 int code; 158 159 if ((keypad->cols_en_mask & (1 << col)) == 0) 160 continue; /* Column is not enabled */ 161 162 bits_changed = keypad->matrix_stable_state[col] ^ 163 matrix_volatile_state[col]; 164 165 if (bits_changed == 0) 166 continue; /* Column does not contain changes */ 167 168 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { 169 if ((keypad->rows_en_mask & (1 << row)) == 0) 170 continue; /* Row is not enabled */ 171 if ((bits_changed & (1 << row)) == 0) 172 continue; /* Row does not contain changes */ 173 174 code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); 175 input_event(input_dev, EV_MSC, MSC_SCAN, code); 176 input_report_key(input_dev, keypad->keycodes[code], 177 matrix_volatile_state[col] & (1 << row)); 178 dev_dbg(&input_dev->dev, "Event code: %d, val: %d", 179 keypad->keycodes[code], 180 matrix_volatile_state[col] & (1 << row)); 181 } 182 } 183 input_sync(input_dev); 184 } 185 186 /* 187 * imx_keypad_check_for_events is the timer handler. 188 */ 189 static void imx_keypad_check_for_events(unsigned long data) 190 { 191 struct imx_keypad *keypad = (struct imx_keypad *) data; 192 unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS]; 193 unsigned short reg_val; 194 bool state_changed, is_zero_matrix; 195 int i; 196 197 memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state)); 198 199 imx_keypad_scan_matrix(keypad, matrix_volatile_state); 200 201 state_changed = false; 202 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 203 if ((keypad->cols_en_mask & (1 << i)) == 0) 204 continue; 205 206 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) { 207 state_changed = true; 208 break; 209 } 210 } 211 212 /* 213 * If the matrix state is changed from the previous scan 214 * (Re)Begin the debouncing process, saving the new state in 215 * keypad->matrix_unstable_state. 216 * else 217 * Increase the count of number of scans with a stable state. 218 */ 219 if (state_changed) { 220 memcpy(keypad->matrix_unstable_state, matrix_volatile_state, 221 sizeof(matrix_volatile_state)); 222 keypad->stable_count = 0; 223 } else 224 keypad->stable_count++; 225 226 /* 227 * If the matrix is not as stable as we want reschedule scan 228 * in the near future. 229 */ 230 if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) { 231 mod_timer(&keypad->check_matrix_timer, 232 jiffies + msecs_to_jiffies(10)); 233 return; 234 } 235 236 /* 237 * If the matrix state is stable, fire the events and save the new 238 * stable state. Note, if the matrix is kept stable for longer 239 * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all 240 * events have already been generated. 241 */ 242 if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) { 243 imx_keypad_fire_events(keypad, matrix_volatile_state); 244 245 memcpy(keypad->matrix_stable_state, matrix_volatile_state, 246 sizeof(matrix_volatile_state)); 247 } 248 249 is_zero_matrix = true; 250 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 251 if (matrix_volatile_state[i] != 0) { 252 is_zero_matrix = false; 253 break; 254 } 255 } 256 257 258 if (is_zero_matrix) { 259 /* 260 * All keys have been released. Enable only the KDI 261 * interrupt for future key presses (clear the KDI 262 * status bit and its sync chain before that). 263 */ 264 reg_val = readw(keypad->mmio_base + KPSR); 265 reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC; 266 writew(reg_val, keypad->mmio_base + KPSR); 267 268 reg_val = readw(keypad->mmio_base + KPSR); 269 reg_val |= KBD_STAT_KDIE; 270 reg_val &= ~KBD_STAT_KRIE; 271 writew(reg_val, keypad->mmio_base + KPSR); 272 } else { 273 /* 274 * Some keys are still pressed. Schedule a rescan in 275 * attempt to detect multiple key presses and enable 276 * the KRI interrupt to react quickly to key release 277 * event. 278 */ 279 mod_timer(&keypad->check_matrix_timer, 280 jiffies + msecs_to_jiffies(60)); 281 282 reg_val = readw(keypad->mmio_base + KPSR); 283 reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS; 284 writew(reg_val, keypad->mmio_base + KPSR); 285 286 reg_val = readw(keypad->mmio_base + KPSR); 287 reg_val |= KBD_STAT_KRIE; 288 reg_val &= ~KBD_STAT_KDIE; 289 writew(reg_val, keypad->mmio_base + KPSR); 290 } 291 } 292 293 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id) 294 { 295 struct imx_keypad *keypad = dev_id; 296 unsigned short reg_val; 297 298 reg_val = readw(keypad->mmio_base + KPSR); 299 300 /* Disable both interrupt types */ 301 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 302 /* Clear interrupts status bits */ 303 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 304 writew(reg_val, keypad->mmio_base + KPSR); 305 306 if (keypad->enabled) { 307 /* The matrix is supposed to be changed */ 308 keypad->stable_count = 0; 309 310 /* Schedule the scanning procedure near in the future */ 311 mod_timer(&keypad->check_matrix_timer, 312 jiffies + msecs_to_jiffies(2)); 313 } 314 315 return IRQ_HANDLED; 316 } 317 318 static void imx_keypad_config(struct imx_keypad *keypad) 319 { 320 unsigned short reg_val; 321 322 /* 323 * Include enabled rows in interrupt generation (KPCR[7:0]) 324 * Configure keypad columns as open-drain (KPCR[15:8]) 325 */ 326 reg_val = readw(keypad->mmio_base + KPCR); 327 reg_val |= keypad->rows_en_mask & 0xff; /* rows */ 328 reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */ 329 writew(reg_val, keypad->mmio_base + KPCR); 330 331 /* Write 0's to KPDR[15:8] (Colums) */ 332 reg_val = readw(keypad->mmio_base + KPDR); 333 reg_val &= 0x00ff; 334 writew(reg_val, keypad->mmio_base + KPDR); 335 336 /* Configure columns as output, rows as input (KDDR[15:0]) */ 337 writew(0xff00, keypad->mmio_base + KDDR); 338 339 /* 340 * Clear Key Depress and Key Release status bit. 341 * Clear both synchronizer chain. 342 */ 343 reg_val = readw(keypad->mmio_base + KPSR); 344 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD | 345 KBD_STAT_KDSC | KBD_STAT_KRSS; 346 writew(reg_val, keypad->mmio_base + KPSR); 347 348 /* Enable KDI and disable KRI (avoid false release events). */ 349 reg_val |= KBD_STAT_KDIE; 350 reg_val &= ~KBD_STAT_KRIE; 351 writew(reg_val, keypad->mmio_base + KPSR); 352 } 353 354 static void imx_keypad_inhibit(struct imx_keypad *keypad) 355 { 356 unsigned short reg_val; 357 358 /* Inhibit KDI and KRI interrupts. */ 359 reg_val = readw(keypad->mmio_base + KPSR); 360 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 361 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 362 writew(reg_val, keypad->mmio_base + KPSR); 363 364 /* Colums as open drain and disable all rows */ 365 writew(0xff00, keypad->mmio_base + KPCR); 366 } 367 368 static void imx_keypad_close(struct input_dev *dev) 369 { 370 struct imx_keypad *keypad = input_get_drvdata(dev); 371 372 dev_dbg(&dev->dev, ">%s\n", __func__); 373 374 /* Mark keypad as being inactive */ 375 keypad->enabled = false; 376 synchronize_irq(keypad->irq); 377 del_timer_sync(&keypad->check_matrix_timer); 378 379 imx_keypad_inhibit(keypad); 380 381 /* Disable clock unit */ 382 clk_disable_unprepare(keypad->clk); 383 } 384 385 static int imx_keypad_open(struct input_dev *dev) 386 { 387 struct imx_keypad *keypad = input_get_drvdata(dev); 388 int error; 389 390 dev_dbg(&dev->dev, ">%s\n", __func__); 391 392 /* Enable the kpp clock */ 393 error = clk_prepare_enable(keypad->clk); 394 if (error) 395 return error; 396 397 /* We became active from now */ 398 keypad->enabled = true; 399 400 imx_keypad_config(keypad); 401 402 /* Sanity control, not all the rows must be actived now. */ 403 if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) { 404 dev_err(&dev->dev, 405 "too many keys pressed, control pins initialisation\n"); 406 goto open_err; 407 } 408 409 return 0; 410 411 open_err: 412 imx_keypad_close(dev); 413 return -EIO; 414 } 415 416 static int __devinit imx_keypad_probe(struct platform_device *pdev) 417 { 418 const struct matrix_keymap_data *keymap_data = pdev->dev.platform_data; 419 struct imx_keypad *keypad; 420 struct input_dev *input_dev; 421 struct resource *res; 422 int irq, error, i; 423 424 if (keymap_data == NULL) { 425 dev_err(&pdev->dev, "no keymap defined\n"); 426 return -EINVAL; 427 } 428 429 irq = platform_get_irq(pdev, 0); 430 if (irq < 0) { 431 dev_err(&pdev->dev, "no irq defined in platform data\n"); 432 return -EINVAL; 433 } 434 435 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 436 if (res == NULL) { 437 dev_err(&pdev->dev, "no I/O memory defined in platform data\n"); 438 return -EINVAL; 439 } 440 441 res = request_mem_region(res->start, resource_size(res), pdev->name); 442 if (res == NULL) { 443 dev_err(&pdev->dev, "failed to request I/O memory\n"); 444 return -EBUSY; 445 } 446 447 input_dev = input_allocate_device(); 448 if (!input_dev) { 449 dev_err(&pdev->dev, "failed to allocate the input device\n"); 450 error = -ENOMEM; 451 goto failed_rel_mem; 452 } 453 454 keypad = kzalloc(sizeof(struct imx_keypad), GFP_KERNEL); 455 if (!keypad) { 456 dev_err(&pdev->dev, "not enough memory for driver data\n"); 457 error = -ENOMEM; 458 goto failed_free_input; 459 } 460 461 keypad->input_dev = input_dev; 462 keypad->irq = irq; 463 keypad->stable_count = 0; 464 465 setup_timer(&keypad->check_matrix_timer, 466 imx_keypad_check_for_events, (unsigned long) keypad); 467 468 keypad->mmio_base = ioremap(res->start, resource_size(res)); 469 if (keypad->mmio_base == NULL) { 470 dev_err(&pdev->dev, "failed to remap I/O memory\n"); 471 error = -ENOMEM; 472 goto failed_free_priv; 473 } 474 475 keypad->clk = clk_get(&pdev->dev, NULL); 476 if (IS_ERR(keypad->clk)) { 477 dev_err(&pdev->dev, "failed to get keypad clock\n"); 478 error = PTR_ERR(keypad->clk); 479 goto failed_unmap; 480 } 481 482 /* Search for rows and cols enabled */ 483 for (i = 0; i < keymap_data->keymap_size; i++) { 484 keypad->rows_en_mask |= 1 << KEY_ROW(keymap_data->keymap[i]); 485 keypad->cols_en_mask |= 1 << KEY_COL(keymap_data->keymap[i]); 486 } 487 488 if (keypad->rows_en_mask > ((1 << MAX_MATRIX_KEY_ROWS) - 1) || 489 keypad->cols_en_mask > ((1 << MAX_MATRIX_KEY_COLS) - 1)) { 490 dev_err(&pdev->dev, 491 "invalid key data (too many rows or colums)\n"); 492 error = -EINVAL; 493 goto failed_clock_put; 494 } 495 dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask); 496 dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask); 497 498 /* Init the Input device */ 499 input_dev->name = pdev->name; 500 input_dev->id.bustype = BUS_HOST; 501 input_dev->dev.parent = &pdev->dev; 502 input_dev->open = imx_keypad_open; 503 input_dev->close = imx_keypad_close; 504 505 error = matrix_keypad_build_keymap(keymap_data, NULL, 506 MAX_MATRIX_KEY_ROWS, 507 MAX_MATRIX_KEY_COLS, 508 keypad->keycodes, input_dev); 509 if (error) { 510 dev_err(&pdev->dev, "failed to build keymap\n"); 511 goto failed_clock_put; 512 } 513 514 __set_bit(EV_REP, input_dev->evbit); 515 input_set_capability(input_dev, EV_MSC, MSC_SCAN); 516 input_set_drvdata(input_dev, keypad); 517 518 /* Ensure that the keypad will stay dormant until opened */ 519 clk_prepare_enable(keypad->clk); 520 imx_keypad_inhibit(keypad); 521 clk_disable_unprepare(keypad->clk); 522 523 error = request_irq(irq, imx_keypad_irq_handler, 0, 524 pdev->name, keypad); 525 if (error) { 526 dev_err(&pdev->dev, "failed to request IRQ\n"); 527 goto failed_clock_put; 528 } 529 530 /* Register the input device */ 531 error = input_register_device(input_dev); 532 if (error) { 533 dev_err(&pdev->dev, "failed to register input device\n"); 534 goto failed_free_irq; 535 } 536 537 platform_set_drvdata(pdev, keypad); 538 device_init_wakeup(&pdev->dev, 1); 539 540 return 0; 541 542 failed_free_irq: 543 free_irq(irq, pdev); 544 failed_clock_put: 545 clk_put(keypad->clk); 546 failed_unmap: 547 iounmap(keypad->mmio_base); 548 failed_free_priv: 549 kfree(keypad); 550 failed_free_input: 551 input_free_device(input_dev); 552 failed_rel_mem: 553 release_mem_region(res->start, resource_size(res)); 554 return error; 555 } 556 557 static int __devexit imx_keypad_remove(struct platform_device *pdev) 558 { 559 struct imx_keypad *keypad = platform_get_drvdata(pdev); 560 struct resource *res; 561 562 dev_dbg(&pdev->dev, ">%s\n", __func__); 563 564 platform_set_drvdata(pdev, NULL); 565 566 input_unregister_device(keypad->input_dev); 567 568 free_irq(keypad->irq, keypad); 569 clk_put(keypad->clk); 570 571 iounmap(keypad->mmio_base); 572 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 573 release_mem_region(res->start, resource_size(res)); 574 575 kfree(keypad); 576 577 return 0; 578 } 579 580 #ifdef CONFIG_PM_SLEEP 581 static int imx_kbd_suspend(struct device *dev) 582 { 583 struct platform_device *pdev = to_platform_device(dev); 584 struct imx_keypad *kbd = platform_get_drvdata(pdev); 585 struct input_dev *input_dev = kbd->input_dev; 586 587 /* imx kbd can wake up system even clock is disabled */ 588 mutex_lock(&input_dev->mutex); 589 590 if (input_dev->users) 591 clk_disable_unprepare(kbd->clk); 592 593 mutex_unlock(&input_dev->mutex); 594 595 if (device_may_wakeup(&pdev->dev)) 596 enable_irq_wake(kbd->irq); 597 598 return 0; 599 } 600 601 static int imx_kbd_resume(struct device *dev) 602 { 603 struct platform_device *pdev = to_platform_device(dev); 604 struct imx_keypad *kbd = platform_get_drvdata(pdev); 605 struct input_dev *input_dev = kbd->input_dev; 606 int ret = 0; 607 608 if (device_may_wakeup(&pdev->dev)) 609 disable_irq_wake(kbd->irq); 610 611 mutex_lock(&input_dev->mutex); 612 613 if (input_dev->users) { 614 ret = clk_prepare_enable(kbd->clk); 615 if (ret) 616 goto err_clk; 617 } 618 619 err_clk: 620 mutex_unlock(&input_dev->mutex); 621 622 return ret; 623 } 624 #endif 625 626 static SIMPLE_DEV_PM_OPS(imx_kbd_pm_ops, imx_kbd_suspend, imx_kbd_resume); 627 628 static struct platform_driver imx_keypad_driver = { 629 .driver = { 630 .name = "imx-keypad", 631 .owner = THIS_MODULE, 632 .pm = &imx_kbd_pm_ops, 633 }, 634 .probe = imx_keypad_probe, 635 .remove = __devexit_p(imx_keypad_remove), 636 }; 637 module_platform_driver(imx_keypad_driver); 638 639 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>"); 640 MODULE_DESCRIPTION("IMX Keypad Port Driver"); 641 MODULE_LICENSE("GPL v2"); 642 MODULE_ALIAS("platform:imx-keypad"); 643