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/of.h> 24 #include <linux/platform_device.h> 25 #include <linux/slab.h> 26 #include <linux/timer.h> 27 28 /* 29 * Keypad Controller registers (halfword) 30 */ 31 #define KPCR 0x00 /* Keypad Control Register */ 32 33 #define KPSR 0x02 /* Keypad Status Register */ 34 #define KBD_STAT_KPKD (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */ 35 #define KBD_STAT_KPKR (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */ 36 #define KBD_STAT_KDSC (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/ 37 #define KBD_STAT_KRSS (0x1 << 3) /* Key Release Synch Status bit (w1c)*/ 38 #define KBD_STAT_KDIE (0x1 << 8) /* Key Depress Interrupt Enable Status bit */ 39 #define KBD_STAT_KRIE (0x1 << 9) /* Key Release Interrupt Enable */ 40 #define KBD_STAT_KPPEN (0x1 << 10) /* Keypad Clock Enable */ 41 42 #define KDDR 0x04 /* Keypad Data Direction Register */ 43 #define KPDR 0x06 /* Keypad Data Register */ 44 45 #define MAX_MATRIX_KEY_ROWS 8 46 #define MAX_MATRIX_KEY_COLS 8 47 #define MATRIX_ROW_SHIFT 3 48 49 #define MAX_MATRIX_KEY_NUM (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS) 50 51 struct imx_keypad { 52 53 struct clk *clk; 54 struct input_dev *input_dev; 55 void __iomem *mmio_base; 56 57 int irq; 58 struct timer_list check_matrix_timer; 59 60 /* 61 * The matrix is stable only if no changes are detected after 62 * IMX_KEYPAD_SCANS_FOR_STABILITY scans 63 */ 64 #define IMX_KEYPAD_SCANS_FOR_STABILITY 3 65 int stable_count; 66 67 bool enabled; 68 69 /* Masks for enabled rows/cols */ 70 unsigned short rows_en_mask; 71 unsigned short cols_en_mask; 72 73 unsigned short keycodes[MAX_MATRIX_KEY_NUM]; 74 75 /* 76 * Matrix states: 77 * -stable: achieved after a complete debounce process. 78 * -unstable: used in the debouncing process. 79 */ 80 unsigned short matrix_stable_state[MAX_MATRIX_KEY_COLS]; 81 unsigned short matrix_unstable_state[MAX_MATRIX_KEY_COLS]; 82 }; 83 84 /* Scan the matrix and return the new state in *matrix_volatile_state. */ 85 static void imx_keypad_scan_matrix(struct imx_keypad *keypad, 86 unsigned short *matrix_volatile_state) 87 { 88 int col; 89 unsigned short reg_val; 90 91 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 92 if ((keypad->cols_en_mask & (1 << col)) == 0) 93 continue; 94 /* 95 * Discharge keypad capacitance: 96 * 2. write 1s on column data. 97 * 3. configure columns as totem-pole to discharge capacitance. 98 * 4. configure columns as open-drain. 99 */ 100 reg_val = readw(keypad->mmio_base + KPDR); 101 reg_val |= 0xff00; 102 writew(reg_val, keypad->mmio_base + KPDR); 103 104 reg_val = readw(keypad->mmio_base + KPCR); 105 reg_val &= ~((keypad->cols_en_mask & 0xff) << 8); 106 writew(reg_val, keypad->mmio_base + KPCR); 107 108 udelay(2); 109 110 reg_val = readw(keypad->mmio_base + KPCR); 111 reg_val |= (keypad->cols_en_mask & 0xff) << 8; 112 writew(reg_val, keypad->mmio_base + KPCR); 113 114 /* 115 * 5. Write a single column to 0, others to 1. 116 * 6. Sample row inputs and save data. 117 * 7. Repeat steps 2 - 6 for remaining columns. 118 */ 119 reg_val = readw(keypad->mmio_base + KPDR); 120 reg_val &= ~(1 << (8 + col)); 121 writew(reg_val, keypad->mmio_base + KPDR); 122 123 /* 124 * Delay added to avoid propagating the 0 from column to row 125 * when scanning. 126 */ 127 udelay(5); 128 129 /* 130 * 1s in matrix_volatile_state[col] means key pressures 131 * throw data from non enabled rows. 132 */ 133 reg_val = readw(keypad->mmio_base + KPDR); 134 matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask; 135 } 136 137 /* 138 * Return in standby mode: 139 * 9. write 0s to columns 140 */ 141 reg_val = readw(keypad->mmio_base + KPDR); 142 reg_val &= 0x00ff; 143 writew(reg_val, keypad->mmio_base + KPDR); 144 } 145 146 /* 147 * Compare the new matrix state (volatile) with the stable one stored in 148 * keypad->matrix_stable_state and fire events if changes are detected. 149 */ 150 static void imx_keypad_fire_events(struct imx_keypad *keypad, 151 unsigned short *matrix_volatile_state) 152 { 153 struct input_dev *input_dev = keypad->input_dev; 154 int row, col; 155 156 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 157 unsigned short bits_changed; 158 int code; 159 160 if ((keypad->cols_en_mask & (1 << col)) == 0) 161 continue; /* Column is not enabled */ 162 163 bits_changed = keypad->matrix_stable_state[col] ^ 164 matrix_volatile_state[col]; 165 166 if (bits_changed == 0) 167 continue; /* Column does not contain changes */ 168 169 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { 170 if ((keypad->rows_en_mask & (1 << row)) == 0) 171 continue; /* Row is not enabled */ 172 if ((bits_changed & (1 << row)) == 0) 173 continue; /* Row does not contain changes */ 174 175 code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); 176 input_event(input_dev, EV_MSC, MSC_SCAN, code); 177 input_report_key(input_dev, keypad->keycodes[code], 178 matrix_volatile_state[col] & (1 << row)); 179 dev_dbg(&input_dev->dev, "Event code: %d, val: %d", 180 keypad->keycodes[code], 181 matrix_volatile_state[col] & (1 << row)); 182 } 183 } 184 input_sync(input_dev); 185 } 186 187 /* 188 * imx_keypad_check_for_events is the timer handler. 189 */ 190 static void imx_keypad_check_for_events(unsigned long data) 191 { 192 struct imx_keypad *keypad = (struct imx_keypad *) data; 193 unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS]; 194 unsigned short reg_val; 195 bool state_changed, is_zero_matrix; 196 int i; 197 198 memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state)); 199 200 imx_keypad_scan_matrix(keypad, matrix_volatile_state); 201 202 state_changed = false; 203 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 204 if ((keypad->cols_en_mask & (1 << i)) == 0) 205 continue; 206 207 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) { 208 state_changed = true; 209 break; 210 } 211 } 212 213 /* 214 * If the matrix state is changed from the previous scan 215 * (Re)Begin the debouncing process, saving the new state in 216 * keypad->matrix_unstable_state. 217 * else 218 * Increase the count of number of scans with a stable state. 219 */ 220 if (state_changed) { 221 memcpy(keypad->matrix_unstable_state, matrix_volatile_state, 222 sizeof(matrix_volatile_state)); 223 keypad->stable_count = 0; 224 } else 225 keypad->stable_count++; 226 227 /* 228 * If the matrix is not as stable as we want reschedule scan 229 * in the near future. 230 */ 231 if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) { 232 mod_timer(&keypad->check_matrix_timer, 233 jiffies + msecs_to_jiffies(10)); 234 return; 235 } 236 237 /* 238 * If the matrix state is stable, fire the events and save the new 239 * stable state. Note, if the matrix is kept stable for longer 240 * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all 241 * events have already been generated. 242 */ 243 if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) { 244 imx_keypad_fire_events(keypad, matrix_volatile_state); 245 246 memcpy(keypad->matrix_stable_state, matrix_volatile_state, 247 sizeof(matrix_volatile_state)); 248 } 249 250 is_zero_matrix = true; 251 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 252 if (matrix_volatile_state[i] != 0) { 253 is_zero_matrix = false; 254 break; 255 } 256 } 257 258 259 if (is_zero_matrix) { 260 /* 261 * All keys have been released. Enable only the KDI 262 * interrupt for future key presses (clear the KDI 263 * status bit and its sync chain before that). 264 */ 265 reg_val = readw(keypad->mmio_base + KPSR); 266 reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC; 267 writew(reg_val, keypad->mmio_base + KPSR); 268 269 reg_val = readw(keypad->mmio_base + KPSR); 270 reg_val |= KBD_STAT_KDIE; 271 reg_val &= ~KBD_STAT_KRIE; 272 writew(reg_val, keypad->mmio_base + KPSR); 273 } else { 274 /* 275 * Some keys are still pressed. Schedule a rescan in 276 * attempt to detect multiple key presses and enable 277 * the KRI interrupt to react quickly to key release 278 * event. 279 */ 280 mod_timer(&keypad->check_matrix_timer, 281 jiffies + msecs_to_jiffies(60)); 282 283 reg_val = readw(keypad->mmio_base + KPSR); 284 reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS; 285 writew(reg_val, keypad->mmio_base + KPSR); 286 287 reg_val = readw(keypad->mmio_base + KPSR); 288 reg_val |= KBD_STAT_KRIE; 289 reg_val &= ~KBD_STAT_KDIE; 290 writew(reg_val, keypad->mmio_base + KPSR); 291 } 292 } 293 294 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id) 295 { 296 struct imx_keypad *keypad = dev_id; 297 unsigned short reg_val; 298 299 reg_val = readw(keypad->mmio_base + KPSR); 300 301 /* Disable both interrupt types */ 302 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 303 /* Clear interrupts status bits */ 304 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 305 writew(reg_val, keypad->mmio_base + KPSR); 306 307 if (keypad->enabled) { 308 /* The matrix is supposed to be changed */ 309 keypad->stable_count = 0; 310 311 /* Schedule the scanning procedure near in the future */ 312 mod_timer(&keypad->check_matrix_timer, 313 jiffies + msecs_to_jiffies(2)); 314 } 315 316 return IRQ_HANDLED; 317 } 318 319 static void imx_keypad_config(struct imx_keypad *keypad) 320 { 321 unsigned short reg_val; 322 323 /* 324 * Include enabled rows in interrupt generation (KPCR[7:0]) 325 * Configure keypad columns as open-drain (KPCR[15:8]) 326 */ 327 reg_val = readw(keypad->mmio_base + KPCR); 328 reg_val |= keypad->rows_en_mask & 0xff; /* rows */ 329 reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */ 330 writew(reg_val, keypad->mmio_base + KPCR); 331 332 /* Write 0's to KPDR[15:8] (Colums) */ 333 reg_val = readw(keypad->mmio_base + KPDR); 334 reg_val &= 0x00ff; 335 writew(reg_val, keypad->mmio_base + KPDR); 336 337 /* Configure columns as output, rows as input (KDDR[15:0]) */ 338 writew(0xff00, keypad->mmio_base + KDDR); 339 340 /* 341 * Clear Key Depress and Key Release status bit. 342 * Clear both synchronizer chain. 343 */ 344 reg_val = readw(keypad->mmio_base + KPSR); 345 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD | 346 KBD_STAT_KDSC | KBD_STAT_KRSS; 347 writew(reg_val, keypad->mmio_base + KPSR); 348 349 /* Enable KDI and disable KRI (avoid false release events). */ 350 reg_val |= KBD_STAT_KDIE; 351 reg_val &= ~KBD_STAT_KRIE; 352 writew(reg_val, keypad->mmio_base + KPSR); 353 } 354 355 static void imx_keypad_inhibit(struct imx_keypad *keypad) 356 { 357 unsigned short reg_val; 358 359 /* Inhibit KDI and KRI interrupts. */ 360 reg_val = readw(keypad->mmio_base + KPSR); 361 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 362 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 363 writew(reg_val, keypad->mmio_base + KPSR); 364 365 /* Colums as open drain and disable all rows */ 366 reg_val = (keypad->cols_en_mask & 0xff) << 8; 367 writew(reg_val, keypad->mmio_base + KPCR); 368 } 369 370 static void imx_keypad_close(struct input_dev *dev) 371 { 372 struct imx_keypad *keypad = input_get_drvdata(dev); 373 374 dev_dbg(&dev->dev, ">%s\n", __func__); 375 376 /* Mark keypad as being inactive */ 377 keypad->enabled = false; 378 synchronize_irq(keypad->irq); 379 del_timer_sync(&keypad->check_matrix_timer); 380 381 imx_keypad_inhibit(keypad); 382 383 /* Disable clock unit */ 384 clk_disable_unprepare(keypad->clk); 385 } 386 387 static int imx_keypad_open(struct input_dev *dev) 388 { 389 struct imx_keypad *keypad = input_get_drvdata(dev); 390 int error; 391 392 dev_dbg(&dev->dev, ">%s\n", __func__); 393 394 /* Enable the kpp clock */ 395 error = clk_prepare_enable(keypad->clk); 396 if (error) 397 return error; 398 399 /* We became active from now */ 400 keypad->enabled = true; 401 402 imx_keypad_config(keypad); 403 404 /* Sanity control, not all the rows must be actived now. */ 405 if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) { 406 dev_err(&dev->dev, 407 "too many keys pressed, control pins initialisation\n"); 408 goto open_err; 409 } 410 411 return 0; 412 413 open_err: 414 imx_keypad_close(dev); 415 return -EIO; 416 } 417 418 #ifdef CONFIG_OF 419 static struct of_device_id imx_keypad_of_match[] = { 420 { .compatible = "fsl,imx21-kpp", }, 421 { /* sentinel */ } 422 }; 423 MODULE_DEVICE_TABLE(of, imx_keypad_of_match); 424 #endif 425 426 static int imx_keypad_probe(struct platform_device *pdev) 427 { 428 const struct matrix_keymap_data *keymap_data = pdev->dev.platform_data; 429 struct imx_keypad *keypad; 430 struct input_dev *input_dev; 431 struct resource *res; 432 int irq, error, i, row, col; 433 434 if (!keymap_data && !pdev->dev.of_node) { 435 dev_err(&pdev->dev, "no keymap defined\n"); 436 return -EINVAL; 437 } 438 439 irq = platform_get_irq(pdev, 0); 440 if (irq < 0) { 441 dev_err(&pdev->dev, "no irq defined in platform data\n"); 442 return -EINVAL; 443 } 444 445 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 446 if (res == NULL) { 447 dev_err(&pdev->dev, "no I/O memory defined in platform data\n"); 448 return -EINVAL; 449 } 450 451 input_dev = devm_input_allocate_device(&pdev->dev); 452 if (!input_dev) { 453 dev_err(&pdev->dev, "failed to allocate the input device\n"); 454 return -ENOMEM; 455 } 456 457 keypad = devm_kzalloc(&pdev->dev, sizeof(struct imx_keypad), 458 GFP_KERNEL); 459 if (!keypad) { 460 dev_err(&pdev->dev, "not enough memory for driver data\n"); 461 return -ENOMEM; 462 } 463 464 keypad->input_dev = input_dev; 465 keypad->irq = irq; 466 keypad->stable_count = 0; 467 468 setup_timer(&keypad->check_matrix_timer, 469 imx_keypad_check_for_events, (unsigned long) keypad); 470 471 keypad->mmio_base = devm_ioremap_resource(&pdev->dev, res); 472 if (IS_ERR(keypad->mmio_base)) 473 return PTR_ERR(keypad->mmio_base); 474 475 keypad->clk = devm_clk_get(&pdev->dev, NULL); 476 if (IS_ERR(keypad->clk)) { 477 dev_err(&pdev->dev, "failed to get keypad clock\n"); 478 return PTR_ERR(keypad->clk); 479 } 480 481 /* Init the Input device */ 482 input_dev->name = pdev->name; 483 input_dev->id.bustype = BUS_HOST; 484 input_dev->dev.parent = &pdev->dev; 485 input_dev->open = imx_keypad_open; 486 input_dev->close = imx_keypad_close; 487 488 error = matrix_keypad_build_keymap(keymap_data, NULL, 489 MAX_MATRIX_KEY_ROWS, 490 MAX_MATRIX_KEY_COLS, 491 keypad->keycodes, input_dev); 492 if (error) { 493 dev_err(&pdev->dev, "failed to build keymap\n"); 494 return error; 495 } 496 497 /* Search for rows and cols enabled */ 498 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { 499 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 500 i = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); 501 if (keypad->keycodes[i] != KEY_RESERVED) { 502 keypad->rows_en_mask |= 1 << row; 503 keypad->cols_en_mask |= 1 << col; 504 } 505 } 506 } 507 dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask); 508 dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask); 509 510 __set_bit(EV_REP, input_dev->evbit); 511 input_set_capability(input_dev, EV_MSC, MSC_SCAN); 512 input_set_drvdata(input_dev, keypad); 513 514 /* Ensure that the keypad will stay dormant until opened */ 515 clk_prepare_enable(keypad->clk); 516 imx_keypad_inhibit(keypad); 517 clk_disable_unprepare(keypad->clk); 518 519 error = devm_request_irq(&pdev->dev, irq, imx_keypad_irq_handler, 0, 520 pdev->name, keypad); 521 if (error) { 522 dev_err(&pdev->dev, "failed to request IRQ\n"); 523 return error; 524 } 525 526 /* Register the input device */ 527 error = input_register_device(input_dev); 528 if (error) { 529 dev_err(&pdev->dev, "failed to register input device\n"); 530 return error; 531 } 532 533 platform_set_drvdata(pdev, keypad); 534 device_init_wakeup(&pdev->dev, 1); 535 536 return 0; 537 } 538 539 #ifdef CONFIG_PM_SLEEP 540 static int imx_kbd_suspend(struct device *dev) 541 { 542 struct platform_device *pdev = to_platform_device(dev); 543 struct imx_keypad *kbd = platform_get_drvdata(pdev); 544 struct input_dev *input_dev = kbd->input_dev; 545 546 /* imx kbd can wake up system even clock is disabled */ 547 mutex_lock(&input_dev->mutex); 548 549 if (input_dev->users) 550 clk_disable_unprepare(kbd->clk); 551 552 mutex_unlock(&input_dev->mutex); 553 554 if (device_may_wakeup(&pdev->dev)) 555 enable_irq_wake(kbd->irq); 556 557 return 0; 558 } 559 560 static int imx_kbd_resume(struct device *dev) 561 { 562 struct platform_device *pdev = to_platform_device(dev); 563 struct imx_keypad *kbd = platform_get_drvdata(pdev); 564 struct input_dev *input_dev = kbd->input_dev; 565 int ret = 0; 566 567 if (device_may_wakeup(&pdev->dev)) 568 disable_irq_wake(kbd->irq); 569 570 mutex_lock(&input_dev->mutex); 571 572 if (input_dev->users) { 573 ret = clk_prepare_enable(kbd->clk); 574 if (ret) 575 goto err_clk; 576 } 577 578 err_clk: 579 mutex_unlock(&input_dev->mutex); 580 581 return ret; 582 } 583 #endif 584 585 static SIMPLE_DEV_PM_OPS(imx_kbd_pm_ops, imx_kbd_suspend, imx_kbd_resume); 586 587 static struct platform_driver imx_keypad_driver = { 588 .driver = { 589 .name = "imx-keypad", 590 .owner = THIS_MODULE, 591 .pm = &imx_kbd_pm_ops, 592 .of_match_table = of_match_ptr(imx_keypad_of_match), 593 }, 594 .probe = imx_keypad_probe, 595 }; 596 module_platform_driver(imx_keypad_driver); 597 598 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>"); 599 MODULE_DESCRIPTION("IMX Keypad Port Driver"); 600 MODULE_LICENSE("GPL v2"); 601 MODULE_ALIAS("platform:imx-keypad"); 602