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/timer.h> 25 26 /* 27 * Keypad Controller registers (halfword) 28 */ 29 #define KPCR 0x00 /* Keypad Control Register */ 30 31 #define KPSR 0x02 /* Keypad Status Register */ 32 #define KBD_STAT_KPKD (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */ 33 #define KBD_STAT_KPKR (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */ 34 #define KBD_STAT_KDSC (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/ 35 #define KBD_STAT_KRSS (0x1 << 3) /* Key Release Synch Status bit (w1c)*/ 36 #define KBD_STAT_KDIE (0x1 << 8) /* Key Depress Interrupt Enable Status bit */ 37 #define KBD_STAT_KRIE (0x1 << 9) /* Key Release Interrupt Enable */ 38 #define KBD_STAT_KPPEN (0x1 << 10) /* Keypad Clock Enable */ 39 40 #define KDDR 0x04 /* Keypad Data Direction Register */ 41 #define KPDR 0x06 /* Keypad Data Register */ 42 43 #define MAX_MATRIX_KEY_ROWS 8 44 #define MAX_MATRIX_KEY_COLS 8 45 #define MATRIX_ROW_SHIFT 3 46 47 #define MAX_MATRIX_KEY_NUM (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS) 48 49 struct imx_keypad { 50 51 struct clk *clk; 52 struct input_dev *input_dev; 53 void __iomem *mmio_base; 54 55 int irq; 56 struct timer_list check_matrix_timer; 57 58 /* 59 * The matrix is stable only if no changes are detected after 60 * IMX_KEYPAD_SCANS_FOR_STABILITY scans 61 */ 62 #define IMX_KEYPAD_SCANS_FOR_STABILITY 3 63 int stable_count; 64 65 bool enabled; 66 67 /* Masks for enabled rows/cols */ 68 unsigned short rows_en_mask; 69 unsigned short cols_en_mask; 70 71 unsigned short keycodes[MAX_MATRIX_KEY_NUM]; 72 73 /* 74 * Matrix states: 75 * -stable: achieved after a complete debounce process. 76 * -unstable: used in the debouncing process. 77 */ 78 unsigned short matrix_stable_state[MAX_MATRIX_KEY_COLS]; 79 unsigned short matrix_unstable_state[MAX_MATRIX_KEY_COLS]; 80 }; 81 82 /* Scan the matrix and return the new state in *matrix_volatile_state. */ 83 static void imx_keypad_scan_matrix(struct imx_keypad *keypad, 84 unsigned short *matrix_volatile_state) 85 { 86 int col; 87 unsigned short reg_val; 88 89 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 90 if ((keypad->cols_en_mask & (1 << col)) == 0) 91 continue; 92 /* 93 * Discharge keypad capacitance: 94 * 2. write 1s on column data. 95 * 3. configure columns as totem-pole to discharge capacitance. 96 * 4. configure columns as open-drain. 97 */ 98 reg_val = readw(keypad->mmio_base + KPDR); 99 reg_val |= 0xff00; 100 writew(reg_val, keypad->mmio_base + KPDR); 101 102 reg_val = readw(keypad->mmio_base + KPCR); 103 reg_val &= ~((keypad->cols_en_mask & 0xff) << 8); 104 writew(reg_val, keypad->mmio_base + KPCR); 105 106 udelay(2); 107 108 reg_val = readw(keypad->mmio_base + KPCR); 109 reg_val |= (keypad->cols_en_mask & 0xff) << 8; 110 writew(reg_val, keypad->mmio_base + KPCR); 111 112 /* 113 * 5. Write a single column to 0, others to 1. 114 * 6. Sample row inputs and save data. 115 * 7. Repeat steps 2 - 6 for remaining columns. 116 */ 117 reg_val = readw(keypad->mmio_base + KPDR); 118 reg_val &= ~(1 << (8 + col)); 119 writew(reg_val, keypad->mmio_base + KPDR); 120 121 /* 122 * Delay added to avoid propagating the 0 from column to row 123 * when scanning. 124 */ 125 udelay(5); 126 127 /* 128 * 1s in matrix_volatile_state[col] means key pressures 129 * throw data from non enabled rows. 130 */ 131 reg_val = readw(keypad->mmio_base + KPDR); 132 matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask; 133 } 134 135 /* 136 * Return in standby mode: 137 * 9. write 0s to columns 138 */ 139 reg_val = readw(keypad->mmio_base + KPDR); 140 reg_val &= 0x00ff; 141 writew(reg_val, keypad->mmio_base + KPDR); 142 } 143 144 /* 145 * Compare the new matrix state (volatile) with the stable one stored in 146 * keypad->matrix_stable_state and fire events if changes are detected. 147 */ 148 static void imx_keypad_fire_events(struct imx_keypad *keypad, 149 unsigned short *matrix_volatile_state) 150 { 151 struct input_dev *input_dev = keypad->input_dev; 152 int row, col; 153 154 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 155 unsigned short bits_changed; 156 int code; 157 158 if ((keypad->cols_en_mask & (1 << col)) == 0) 159 continue; /* Column is not enabled */ 160 161 bits_changed = keypad->matrix_stable_state[col] ^ 162 matrix_volatile_state[col]; 163 164 if (bits_changed == 0) 165 continue; /* Column does not contain changes */ 166 167 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { 168 if ((keypad->rows_en_mask & (1 << row)) == 0) 169 continue; /* Row is not enabled */ 170 if ((bits_changed & (1 << row)) == 0) 171 continue; /* Row does not contain changes */ 172 173 code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); 174 input_event(input_dev, EV_MSC, MSC_SCAN, code); 175 input_report_key(input_dev, keypad->keycodes[code], 176 matrix_volatile_state[col] & (1 << row)); 177 dev_dbg(&input_dev->dev, "Event code: %d, val: %d", 178 keypad->keycodes[code], 179 matrix_volatile_state[col] & (1 << row)); 180 } 181 } 182 input_sync(input_dev); 183 } 184 185 /* 186 * imx_keypad_check_for_events is the timer handler. 187 */ 188 static void imx_keypad_check_for_events(unsigned long data) 189 { 190 struct imx_keypad *keypad = (struct imx_keypad *) data; 191 unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS]; 192 unsigned short reg_val; 193 bool state_changed, is_zero_matrix; 194 int i; 195 196 memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state)); 197 198 imx_keypad_scan_matrix(keypad, matrix_volatile_state); 199 200 state_changed = false; 201 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 202 if ((keypad->cols_en_mask & (1 << i)) == 0) 203 continue; 204 205 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) { 206 state_changed = true; 207 break; 208 } 209 } 210 211 /* 212 * If the matrix state is changed from the previous scan 213 * (Re)Begin the debouncing process, saving the new state in 214 * keypad->matrix_unstable_state. 215 * else 216 * Increase the count of number of scans with a stable state. 217 */ 218 if (state_changed) { 219 memcpy(keypad->matrix_unstable_state, matrix_volatile_state, 220 sizeof(matrix_volatile_state)); 221 keypad->stable_count = 0; 222 } else 223 keypad->stable_count++; 224 225 /* 226 * If the matrix is not as stable as we want reschedule scan 227 * in the near future. 228 */ 229 if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) { 230 mod_timer(&keypad->check_matrix_timer, 231 jiffies + msecs_to_jiffies(10)); 232 return; 233 } 234 235 /* 236 * If the matrix state is stable, fire the events and save the new 237 * stable state. Note, if the matrix is kept stable for longer 238 * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all 239 * events have already been generated. 240 */ 241 if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) { 242 imx_keypad_fire_events(keypad, matrix_volatile_state); 243 244 memcpy(keypad->matrix_stable_state, matrix_volatile_state, 245 sizeof(matrix_volatile_state)); 246 } 247 248 is_zero_matrix = true; 249 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 250 if (matrix_volatile_state[i] != 0) { 251 is_zero_matrix = false; 252 break; 253 } 254 } 255 256 257 if (is_zero_matrix) { 258 /* 259 * All keys have been released. Enable only the KDI 260 * interrupt for future key presses (clear the KDI 261 * status bit and its sync chain before that). 262 */ 263 reg_val = readw(keypad->mmio_base + KPSR); 264 reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC; 265 writew(reg_val, keypad->mmio_base + KPSR); 266 267 reg_val = readw(keypad->mmio_base + KPSR); 268 reg_val |= KBD_STAT_KDIE; 269 reg_val &= ~KBD_STAT_KRIE; 270 writew(reg_val, keypad->mmio_base + KPSR); 271 } else { 272 /* 273 * Some keys are still pressed. Schedule a rescan in 274 * attempt to detect multiple key presses and enable 275 * the KRI interrupt to react quickly to key release 276 * event. 277 */ 278 mod_timer(&keypad->check_matrix_timer, 279 jiffies + msecs_to_jiffies(60)); 280 281 reg_val = readw(keypad->mmio_base + KPSR); 282 reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS; 283 writew(reg_val, keypad->mmio_base + KPSR); 284 285 reg_val = readw(keypad->mmio_base + KPSR); 286 reg_val |= KBD_STAT_KRIE; 287 reg_val &= ~KBD_STAT_KDIE; 288 writew(reg_val, keypad->mmio_base + KPSR); 289 } 290 } 291 292 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id) 293 { 294 struct imx_keypad *keypad = dev_id; 295 unsigned short reg_val; 296 297 reg_val = readw(keypad->mmio_base + KPSR); 298 299 /* Disable both interrupt types */ 300 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 301 /* Clear interrupts status bits */ 302 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 303 writew(reg_val, keypad->mmio_base + KPSR); 304 305 if (keypad->enabled) { 306 /* The matrix is supposed to be changed */ 307 keypad->stable_count = 0; 308 309 /* Schedule the scanning procedure near in the future */ 310 mod_timer(&keypad->check_matrix_timer, 311 jiffies + msecs_to_jiffies(2)); 312 } 313 314 return IRQ_HANDLED; 315 } 316 317 static void imx_keypad_config(struct imx_keypad *keypad) 318 { 319 unsigned short reg_val; 320 321 /* 322 * Include enabled rows in interrupt generation (KPCR[7:0]) 323 * Configure keypad columns as open-drain (KPCR[15:8]) 324 */ 325 reg_val = readw(keypad->mmio_base + KPCR); 326 reg_val |= keypad->rows_en_mask & 0xff; /* rows */ 327 reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */ 328 writew(reg_val, keypad->mmio_base + KPCR); 329 330 /* Write 0's to KPDR[15:8] (Colums) */ 331 reg_val = readw(keypad->mmio_base + KPDR); 332 reg_val &= 0x00ff; 333 writew(reg_val, keypad->mmio_base + KPDR); 334 335 /* Configure columns as output, rows as input (KDDR[15:0]) */ 336 writew(0xff00, keypad->mmio_base + KDDR); 337 338 /* 339 * Clear Key Depress and Key Release status bit. 340 * Clear both synchronizer chain. 341 */ 342 reg_val = readw(keypad->mmio_base + KPSR); 343 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD | 344 KBD_STAT_KDSC | KBD_STAT_KRSS; 345 writew(reg_val, keypad->mmio_base + KPSR); 346 347 /* Enable KDI and disable KRI (avoid false release events). */ 348 reg_val |= KBD_STAT_KDIE; 349 reg_val &= ~KBD_STAT_KRIE; 350 writew(reg_val, keypad->mmio_base + KPSR); 351 } 352 353 static void imx_keypad_inhibit(struct imx_keypad *keypad) 354 { 355 unsigned short reg_val; 356 357 /* Inhibit KDI and KRI interrupts. */ 358 reg_val = readw(keypad->mmio_base + KPSR); 359 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 360 writew(reg_val, keypad->mmio_base + KPSR); 361 362 /* Colums as open drain and disable all rows */ 363 writew(0xff00, keypad->mmio_base + KPCR); 364 } 365 366 static void imx_keypad_close(struct input_dev *dev) 367 { 368 struct imx_keypad *keypad = input_get_drvdata(dev); 369 370 dev_dbg(&dev->dev, ">%s\n", __func__); 371 372 /* Mark keypad as being inactive */ 373 keypad->enabled = false; 374 synchronize_irq(keypad->irq); 375 del_timer_sync(&keypad->check_matrix_timer); 376 377 imx_keypad_inhibit(keypad); 378 379 /* Disable clock unit */ 380 clk_disable(keypad->clk); 381 } 382 383 static int imx_keypad_open(struct input_dev *dev) 384 { 385 struct imx_keypad *keypad = input_get_drvdata(dev); 386 387 dev_dbg(&dev->dev, ">%s\n", __func__); 388 389 /* We became active from now */ 390 keypad->enabled = true; 391 392 /* Enable the kpp clock */ 393 clk_enable(keypad->clk); 394 imx_keypad_config(keypad); 395 396 /* Sanity control, not all the rows must be actived now. */ 397 if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) { 398 dev_err(&dev->dev, 399 "too many keys pressed, control pins initialisation\n"); 400 goto open_err; 401 } 402 403 return 0; 404 405 open_err: 406 imx_keypad_close(dev); 407 return -EIO; 408 } 409 410 static int __devinit imx_keypad_probe(struct platform_device *pdev) 411 { 412 const struct matrix_keymap_data *keymap_data = pdev->dev.platform_data; 413 struct imx_keypad *keypad; 414 struct input_dev *input_dev; 415 struct resource *res; 416 int irq, error, i; 417 418 if (keymap_data == NULL) { 419 dev_err(&pdev->dev, "no keymap defined\n"); 420 return -EINVAL; 421 } 422 423 irq = platform_get_irq(pdev, 0); 424 if (irq < 0) { 425 dev_err(&pdev->dev, "no irq defined in platform data\n"); 426 return -EINVAL; 427 } 428 429 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 430 if (res == NULL) { 431 dev_err(&pdev->dev, "no I/O memory defined in platform data\n"); 432 return -EINVAL; 433 } 434 435 res = request_mem_region(res->start, resource_size(res), pdev->name); 436 if (res == NULL) { 437 dev_err(&pdev->dev, "failed to request I/O memory\n"); 438 return -EBUSY; 439 } 440 441 input_dev = input_allocate_device(); 442 if (!input_dev) { 443 dev_err(&pdev->dev, "failed to allocate the input device\n"); 444 error = -ENOMEM; 445 goto failed_rel_mem; 446 } 447 448 keypad = kzalloc(sizeof(struct imx_keypad), GFP_KERNEL); 449 if (!keypad) { 450 dev_err(&pdev->dev, "not enough memory for driver data\n"); 451 error = -ENOMEM; 452 goto failed_free_input; 453 } 454 455 keypad->input_dev = input_dev; 456 keypad->irq = irq; 457 keypad->stable_count = 0; 458 459 setup_timer(&keypad->check_matrix_timer, 460 imx_keypad_check_for_events, (unsigned long) keypad); 461 462 keypad->mmio_base = ioremap(res->start, resource_size(res)); 463 if (keypad->mmio_base == NULL) { 464 dev_err(&pdev->dev, "failed to remap I/O memory\n"); 465 error = -ENOMEM; 466 goto failed_free_priv; 467 } 468 469 keypad->clk = clk_get(&pdev->dev, "kpp"); 470 if (IS_ERR(keypad->clk)) { 471 dev_err(&pdev->dev, "failed to get keypad clock\n"); 472 error = PTR_ERR(keypad->clk); 473 goto failed_unmap; 474 } 475 476 /* Search for rows and cols enabled */ 477 for (i = 0; i < keymap_data->keymap_size; i++) { 478 keypad->rows_en_mask |= 1 << KEY_ROW(keymap_data->keymap[i]); 479 keypad->cols_en_mask |= 1 << KEY_COL(keymap_data->keymap[i]); 480 } 481 482 if (keypad->rows_en_mask > ((1 << MAX_MATRIX_KEY_ROWS) - 1) || 483 keypad->cols_en_mask > ((1 << MAX_MATRIX_KEY_COLS) - 1)) { 484 dev_err(&pdev->dev, 485 "invalid key data (too many rows or colums)\n"); 486 error = -EINVAL; 487 goto failed_clock_put; 488 } 489 dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask); 490 dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask); 491 492 /* Init the Input device */ 493 input_dev->name = pdev->name; 494 input_dev->id.bustype = BUS_HOST; 495 input_dev->dev.parent = &pdev->dev; 496 input_dev->open = imx_keypad_open; 497 input_dev->close = imx_keypad_close; 498 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP); 499 input_dev->keycode = keypad->keycodes; 500 input_dev->keycodesize = sizeof(keypad->keycodes[0]); 501 input_dev->keycodemax = ARRAY_SIZE(keypad->keycodes); 502 503 matrix_keypad_build_keymap(keymap_data, MATRIX_ROW_SHIFT, 504 keypad->keycodes, input_dev->keybit); 505 506 input_set_capability(input_dev, EV_MSC, MSC_SCAN); 507 input_set_drvdata(input_dev, keypad); 508 509 /* Ensure that the keypad will stay dormant until opened */ 510 imx_keypad_inhibit(keypad); 511 512 error = request_irq(irq, imx_keypad_irq_handler, IRQF_DISABLED, 513 pdev->name, keypad); 514 if (error) { 515 dev_err(&pdev->dev, "failed to request IRQ\n"); 516 goto failed_clock_put; 517 } 518 519 /* Register the input device */ 520 error = input_register_device(input_dev); 521 if (error) { 522 dev_err(&pdev->dev, "failed to register input device\n"); 523 goto failed_free_irq; 524 } 525 526 platform_set_drvdata(pdev, keypad); 527 device_init_wakeup(&pdev->dev, 1); 528 529 return 0; 530 531 failed_free_irq: 532 free_irq(irq, pdev); 533 failed_clock_put: 534 clk_put(keypad->clk); 535 failed_unmap: 536 iounmap(keypad->mmio_base); 537 failed_free_priv: 538 kfree(keypad); 539 failed_free_input: 540 input_free_device(input_dev); 541 failed_rel_mem: 542 release_mem_region(res->start, resource_size(res)); 543 return error; 544 } 545 546 static int __devexit imx_keypad_remove(struct platform_device *pdev) 547 { 548 struct imx_keypad *keypad = platform_get_drvdata(pdev); 549 struct resource *res; 550 551 dev_dbg(&pdev->dev, ">%s\n", __func__); 552 553 platform_set_drvdata(pdev, NULL); 554 555 input_unregister_device(keypad->input_dev); 556 557 free_irq(keypad->irq, keypad); 558 clk_put(keypad->clk); 559 560 iounmap(keypad->mmio_base); 561 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 562 release_mem_region(res->start, resource_size(res)); 563 564 kfree(keypad); 565 566 return 0; 567 } 568 569 static struct platform_driver imx_keypad_driver = { 570 .driver = { 571 .name = "imx-keypad", 572 .owner = THIS_MODULE, 573 }, 574 .probe = imx_keypad_probe, 575 .remove = __devexit_p(imx_keypad_remove), 576 }; 577 578 static int __init imx_keypad_init(void) 579 { 580 return platform_driver_register(&imx_keypad_driver); 581 } 582 583 static void __exit imx_keypad_exit(void) 584 { 585 platform_driver_unregister(&imx_keypad_driver); 586 } 587 588 module_init(imx_keypad_init); 589 module_exit(imx_keypad_exit); 590 591 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>"); 592 MODULE_DESCRIPTION("IMX Keypad Port Driver"); 593 MODULE_LICENSE("GPL v2"); 594 MODULE_ALIAS("platform:imx-keypad"); 595