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 10 #include <linux/clk.h> 11 #include <linux/delay.h> 12 #include <linux/device.h> 13 #include <linux/err.h> 14 #include <linux/input/matrix_keypad.h> 15 #include <linux/interrupt.h> 16 #include <linux/io.h> 17 #include <linux/jiffies.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/of.h> 21 #include <linux/platform_device.h> 22 #include <linux/slab.h> 23 #include <linux/timer.h> 24 25 /* 26 * Keypad Controller registers (halfword) 27 */ 28 #define KPCR 0x00 /* Keypad Control Register */ 29 30 #define KPSR 0x02 /* Keypad Status Register */ 31 #define KBD_STAT_KPKD (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */ 32 #define KBD_STAT_KPKR (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */ 33 #define KBD_STAT_KDSC (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/ 34 #define KBD_STAT_KRSS (0x1 << 3) /* Key Release Synch Status bit (w1c)*/ 35 #define KBD_STAT_KDIE (0x1 << 8) /* Key Depress Interrupt Enable Status bit */ 36 #define KBD_STAT_KRIE (0x1 << 9) /* Key Release Interrupt Enable */ 37 #define KBD_STAT_KPPEN (0x1 << 10) /* Keypad Clock Enable */ 38 39 #define KDDR 0x04 /* Keypad Data Direction Register */ 40 #define KPDR 0x06 /* Keypad Data Register */ 41 42 #define MAX_MATRIX_KEY_ROWS 8 43 #define MAX_MATRIX_KEY_COLS 8 44 #define MATRIX_ROW_SHIFT 3 45 46 #define MAX_MATRIX_KEY_NUM (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS) 47 48 struct imx_keypad { 49 50 struct clk *clk; 51 struct input_dev *input_dev; 52 void __iomem *mmio_base; 53 54 int irq; 55 struct timer_list check_matrix_timer; 56 57 /* 58 * The matrix is stable only if no changes are detected after 59 * IMX_KEYPAD_SCANS_FOR_STABILITY scans 60 */ 61 #define IMX_KEYPAD_SCANS_FOR_STABILITY 3 62 int stable_count; 63 64 bool enabled; 65 66 /* Masks for enabled rows/cols */ 67 unsigned short rows_en_mask; 68 unsigned short cols_en_mask; 69 70 unsigned short keycodes[MAX_MATRIX_KEY_NUM]; 71 72 /* 73 * Matrix states: 74 * -stable: achieved after a complete debounce process. 75 * -unstable: used in the debouncing process. 76 */ 77 unsigned short matrix_stable_state[MAX_MATRIX_KEY_COLS]; 78 unsigned short matrix_unstable_state[MAX_MATRIX_KEY_COLS]; 79 }; 80 81 /* Scan the matrix and return the new state in *matrix_volatile_state. */ 82 static void imx_keypad_scan_matrix(struct imx_keypad *keypad, 83 unsigned short *matrix_volatile_state) 84 { 85 int col; 86 unsigned short reg_val; 87 88 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 89 if ((keypad->cols_en_mask & (1 << col)) == 0) 90 continue; 91 /* 92 * Discharge keypad capacitance: 93 * 2. write 1s on column data. 94 * 3. configure columns as totem-pole to discharge capacitance. 95 * 4. configure columns as open-drain. 96 */ 97 reg_val = readw(keypad->mmio_base + KPDR); 98 reg_val |= 0xff00; 99 writew(reg_val, keypad->mmio_base + KPDR); 100 101 reg_val = readw(keypad->mmio_base + KPCR); 102 reg_val &= ~((keypad->cols_en_mask & 0xff) << 8); 103 writew(reg_val, keypad->mmio_base + KPCR); 104 105 udelay(2); 106 107 reg_val = readw(keypad->mmio_base + KPCR); 108 reg_val |= (keypad->cols_en_mask & 0xff) << 8; 109 writew(reg_val, keypad->mmio_base + KPCR); 110 111 /* 112 * 5. Write a single column to 0, others to 1. 113 * 6. Sample row inputs and save data. 114 * 7. Repeat steps 2 - 6 for remaining columns. 115 */ 116 reg_val = readw(keypad->mmio_base + KPDR); 117 reg_val &= ~(1 << (8 + col)); 118 writew(reg_val, keypad->mmio_base + KPDR); 119 120 /* 121 * Delay added to avoid propagating the 0 from column to row 122 * when scanning. 123 */ 124 udelay(5); 125 126 /* 127 * 1s in matrix_volatile_state[col] means key pressures 128 * throw data from non enabled rows. 129 */ 130 reg_val = readw(keypad->mmio_base + KPDR); 131 matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask; 132 } 133 134 /* 135 * Return in standby mode: 136 * 9. write 0s to columns 137 */ 138 reg_val = readw(keypad->mmio_base + KPDR); 139 reg_val &= 0x00ff; 140 writew(reg_val, keypad->mmio_base + KPDR); 141 } 142 143 /* 144 * Compare the new matrix state (volatile) with the stable one stored in 145 * keypad->matrix_stable_state and fire events if changes are detected. 146 */ 147 static void imx_keypad_fire_events(struct imx_keypad *keypad, 148 unsigned short *matrix_volatile_state) 149 { 150 struct input_dev *input_dev = keypad->input_dev; 151 int row, col; 152 153 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 154 unsigned short bits_changed; 155 int code; 156 157 if ((keypad->cols_en_mask & (1 << col)) == 0) 158 continue; /* Column is not enabled */ 159 160 bits_changed = keypad->matrix_stable_state[col] ^ 161 matrix_volatile_state[col]; 162 163 if (bits_changed == 0) 164 continue; /* Column does not contain changes */ 165 166 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { 167 if ((keypad->rows_en_mask & (1 << row)) == 0) 168 continue; /* Row is not enabled */ 169 if ((bits_changed & (1 << row)) == 0) 170 continue; /* Row does not contain changes */ 171 172 code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); 173 input_event(input_dev, EV_MSC, MSC_SCAN, code); 174 input_report_key(input_dev, keypad->keycodes[code], 175 matrix_volatile_state[col] & (1 << row)); 176 dev_dbg(&input_dev->dev, "Event code: %d, val: %d", 177 keypad->keycodes[code], 178 matrix_volatile_state[col] & (1 << row)); 179 } 180 } 181 input_sync(input_dev); 182 } 183 184 /* 185 * imx_keypad_check_for_events is the timer handler. 186 */ 187 static void imx_keypad_check_for_events(struct timer_list *t) 188 { 189 struct imx_keypad *keypad = from_timer(keypad, t, check_matrix_timer); 190 unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS]; 191 unsigned short reg_val; 192 bool state_changed, is_zero_matrix; 193 int i; 194 195 memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state)); 196 197 imx_keypad_scan_matrix(keypad, matrix_volatile_state); 198 199 state_changed = false; 200 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 201 if ((keypad->cols_en_mask & (1 << i)) == 0) 202 continue; 203 204 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) { 205 state_changed = true; 206 break; 207 } 208 } 209 210 /* 211 * If the matrix state is changed from the previous scan 212 * (Re)Begin the debouncing process, saving the new state in 213 * keypad->matrix_unstable_state. 214 * else 215 * Increase the count of number of scans with a stable state. 216 */ 217 if (state_changed) { 218 memcpy(keypad->matrix_unstable_state, matrix_volatile_state, 219 sizeof(matrix_volatile_state)); 220 keypad->stable_count = 0; 221 } else 222 keypad->stable_count++; 223 224 /* 225 * If the matrix is not as stable as we want reschedule scan 226 * in the near future. 227 */ 228 if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) { 229 mod_timer(&keypad->check_matrix_timer, 230 jiffies + msecs_to_jiffies(10)); 231 return; 232 } 233 234 /* 235 * If the matrix state is stable, fire the events and save the new 236 * stable state. Note, if the matrix is kept stable for longer 237 * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all 238 * events have already been generated. 239 */ 240 if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) { 241 imx_keypad_fire_events(keypad, matrix_volatile_state); 242 243 memcpy(keypad->matrix_stable_state, matrix_volatile_state, 244 sizeof(matrix_volatile_state)); 245 } 246 247 is_zero_matrix = true; 248 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 249 if (matrix_volatile_state[i] != 0) { 250 is_zero_matrix = false; 251 break; 252 } 253 } 254 255 256 if (is_zero_matrix) { 257 /* 258 * All keys have been released. Enable only the KDI 259 * interrupt for future key presses (clear the KDI 260 * status bit and its sync chain before that). 261 */ 262 reg_val = readw(keypad->mmio_base + KPSR); 263 reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC; 264 writew(reg_val, keypad->mmio_base + KPSR); 265 266 reg_val = readw(keypad->mmio_base + KPSR); 267 reg_val |= KBD_STAT_KDIE; 268 reg_val &= ~KBD_STAT_KRIE; 269 writew(reg_val, keypad->mmio_base + KPSR); 270 } else { 271 /* 272 * Some keys are still pressed. Schedule a rescan in 273 * attempt to detect multiple key presses and enable 274 * the KRI interrupt to react quickly to key release 275 * event. 276 */ 277 mod_timer(&keypad->check_matrix_timer, 278 jiffies + msecs_to_jiffies(60)); 279 280 reg_val = readw(keypad->mmio_base + KPSR); 281 reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS; 282 writew(reg_val, keypad->mmio_base + KPSR); 283 284 reg_val = readw(keypad->mmio_base + KPSR); 285 reg_val |= KBD_STAT_KRIE; 286 reg_val &= ~KBD_STAT_KDIE; 287 writew(reg_val, keypad->mmio_base + KPSR); 288 } 289 } 290 291 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id) 292 { 293 struct imx_keypad *keypad = dev_id; 294 unsigned short reg_val; 295 296 reg_val = readw(keypad->mmio_base + KPSR); 297 298 /* Disable both interrupt types */ 299 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 300 /* Clear interrupts status bits */ 301 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 302 writew(reg_val, keypad->mmio_base + KPSR); 303 304 if (keypad->enabled) { 305 /* The matrix is supposed to be changed */ 306 keypad->stable_count = 0; 307 308 /* Schedule the scanning procedure near in the future */ 309 mod_timer(&keypad->check_matrix_timer, 310 jiffies + msecs_to_jiffies(2)); 311 } 312 313 return IRQ_HANDLED; 314 } 315 316 static void imx_keypad_config(struct imx_keypad *keypad) 317 { 318 unsigned short reg_val; 319 320 /* 321 * Include enabled rows in interrupt generation (KPCR[7:0]) 322 * Configure keypad columns as open-drain (KPCR[15:8]) 323 */ 324 reg_val = readw(keypad->mmio_base + KPCR); 325 reg_val |= keypad->rows_en_mask & 0xff; /* rows */ 326 reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */ 327 writew(reg_val, keypad->mmio_base + KPCR); 328 329 /* Write 0's to KPDR[15:8] (Colums) */ 330 reg_val = readw(keypad->mmio_base + KPDR); 331 reg_val &= 0x00ff; 332 writew(reg_val, keypad->mmio_base + KPDR); 333 334 /* Configure columns as output, rows as input (KDDR[15:0]) */ 335 writew(0xff00, keypad->mmio_base + KDDR); 336 337 /* 338 * Clear Key Depress and Key Release status bit. 339 * Clear both synchronizer chain. 340 */ 341 reg_val = readw(keypad->mmio_base + KPSR); 342 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD | 343 KBD_STAT_KDSC | KBD_STAT_KRSS; 344 writew(reg_val, keypad->mmio_base + KPSR); 345 346 /* Enable KDI and disable KRI (avoid false release events). */ 347 reg_val |= KBD_STAT_KDIE; 348 reg_val &= ~KBD_STAT_KRIE; 349 writew(reg_val, keypad->mmio_base + KPSR); 350 } 351 352 static void imx_keypad_inhibit(struct imx_keypad *keypad) 353 { 354 unsigned short reg_val; 355 356 /* Inhibit KDI and KRI interrupts. */ 357 reg_val = readw(keypad->mmio_base + KPSR); 358 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 359 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 360 writew(reg_val, keypad->mmio_base + KPSR); 361 362 /* Colums as open drain and disable all rows */ 363 reg_val = (keypad->cols_en_mask & 0xff) << 8; 364 writew(reg_val, keypad->mmio_base + KPCR); 365 } 366 367 static void imx_keypad_close(struct input_dev *dev) 368 { 369 struct imx_keypad *keypad = input_get_drvdata(dev); 370 371 dev_dbg(&dev->dev, ">%s\n", __func__); 372 373 /* Mark keypad as being inactive */ 374 keypad->enabled = false; 375 synchronize_irq(keypad->irq); 376 del_timer_sync(&keypad->check_matrix_timer); 377 378 imx_keypad_inhibit(keypad); 379 380 /* Disable clock unit */ 381 clk_disable_unprepare(keypad->clk); 382 } 383 384 static int imx_keypad_open(struct input_dev *dev) 385 { 386 struct imx_keypad *keypad = input_get_drvdata(dev); 387 int error; 388 389 dev_dbg(&dev->dev, ">%s\n", __func__); 390 391 /* Enable the kpp clock */ 392 error = clk_prepare_enable(keypad->clk); 393 if (error) 394 return error; 395 396 /* We became active from now */ 397 keypad->enabled = true; 398 399 imx_keypad_config(keypad); 400 401 /* Sanity control, not all the rows must be actived now. */ 402 if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) { 403 dev_err(&dev->dev, 404 "too many keys pressed, control pins initialisation\n"); 405 goto open_err; 406 } 407 408 return 0; 409 410 open_err: 411 imx_keypad_close(dev); 412 return -EIO; 413 } 414 415 #ifdef CONFIG_OF 416 static const struct of_device_id imx_keypad_of_match[] = { 417 { .compatible = "fsl,imx21-kpp", }, 418 { /* sentinel */ } 419 }; 420 MODULE_DEVICE_TABLE(of, imx_keypad_of_match); 421 #endif 422 423 static int imx_keypad_probe(struct platform_device *pdev) 424 { 425 const struct matrix_keymap_data *keymap_data = 426 dev_get_platdata(&pdev->dev); 427 struct imx_keypad *keypad; 428 struct input_dev *input_dev; 429 struct resource *res; 430 int irq, error, i, row, col; 431 432 if (!keymap_data && !pdev->dev.of_node) { 433 dev_err(&pdev->dev, "no keymap defined\n"); 434 return -EINVAL; 435 } 436 437 irq = platform_get_irq(pdev, 0); 438 if (irq < 0) { 439 dev_err(&pdev->dev, "no irq defined in platform data\n"); 440 return irq; 441 } 442 443 input_dev = devm_input_allocate_device(&pdev->dev); 444 if (!input_dev) { 445 dev_err(&pdev->dev, "failed to allocate the input device\n"); 446 return -ENOMEM; 447 } 448 449 keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL); 450 if (!keypad) { 451 dev_err(&pdev->dev, "not enough memory for driver data\n"); 452 return -ENOMEM; 453 } 454 455 keypad->input_dev = input_dev; 456 keypad->irq = irq; 457 keypad->stable_count = 0; 458 459 timer_setup(&keypad->check_matrix_timer, 460 imx_keypad_check_for_events, 0); 461 462 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 463 keypad->mmio_base = devm_ioremap_resource(&pdev->dev, res); 464 if (IS_ERR(keypad->mmio_base)) 465 return PTR_ERR(keypad->mmio_base); 466 467 keypad->clk = devm_clk_get(&pdev->dev, NULL); 468 if (IS_ERR(keypad->clk)) { 469 dev_err(&pdev->dev, "failed to get keypad clock\n"); 470 return PTR_ERR(keypad->clk); 471 } 472 473 /* Init the Input device */ 474 input_dev->name = pdev->name; 475 input_dev->id.bustype = BUS_HOST; 476 input_dev->dev.parent = &pdev->dev; 477 input_dev->open = imx_keypad_open; 478 input_dev->close = imx_keypad_close; 479 480 error = matrix_keypad_build_keymap(keymap_data, NULL, 481 MAX_MATRIX_KEY_ROWS, 482 MAX_MATRIX_KEY_COLS, 483 keypad->keycodes, input_dev); 484 if (error) { 485 dev_err(&pdev->dev, "failed to build keymap\n"); 486 return error; 487 } 488 489 /* Search for rows and cols enabled */ 490 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { 491 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 492 i = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); 493 if (keypad->keycodes[i] != KEY_RESERVED) { 494 keypad->rows_en_mask |= 1 << row; 495 keypad->cols_en_mask |= 1 << col; 496 } 497 } 498 } 499 dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask); 500 dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask); 501 502 __set_bit(EV_REP, input_dev->evbit); 503 input_set_capability(input_dev, EV_MSC, MSC_SCAN); 504 input_set_drvdata(input_dev, keypad); 505 506 /* Ensure that the keypad will stay dormant until opened */ 507 error = clk_prepare_enable(keypad->clk); 508 if (error) 509 return error; 510 imx_keypad_inhibit(keypad); 511 clk_disable_unprepare(keypad->clk); 512 513 error = devm_request_irq(&pdev->dev, irq, imx_keypad_irq_handler, 0, 514 pdev->name, keypad); 515 if (error) { 516 dev_err(&pdev->dev, "failed to request IRQ\n"); 517 return error; 518 } 519 520 /* Register the input device */ 521 error = input_register_device(input_dev); 522 if (error) { 523 dev_err(&pdev->dev, "failed to register input device\n"); 524 return error; 525 } 526 527 platform_set_drvdata(pdev, keypad); 528 device_init_wakeup(&pdev->dev, 1); 529 530 return 0; 531 } 532 533 static int __maybe_unused imx_kbd_suspend(struct device *dev) 534 { 535 struct platform_device *pdev = to_platform_device(dev); 536 struct imx_keypad *kbd = platform_get_drvdata(pdev); 537 struct input_dev *input_dev = kbd->input_dev; 538 539 /* imx kbd can wake up system even clock is disabled */ 540 mutex_lock(&input_dev->mutex); 541 542 if (input_dev->users) 543 clk_disable_unprepare(kbd->clk); 544 545 mutex_unlock(&input_dev->mutex); 546 547 if (device_may_wakeup(&pdev->dev)) 548 enable_irq_wake(kbd->irq); 549 550 return 0; 551 } 552 553 static int __maybe_unused imx_kbd_resume(struct device *dev) 554 { 555 struct platform_device *pdev = to_platform_device(dev); 556 struct imx_keypad *kbd = platform_get_drvdata(pdev); 557 struct input_dev *input_dev = kbd->input_dev; 558 int ret = 0; 559 560 if (device_may_wakeup(&pdev->dev)) 561 disable_irq_wake(kbd->irq); 562 563 mutex_lock(&input_dev->mutex); 564 565 if (input_dev->users) { 566 ret = clk_prepare_enable(kbd->clk); 567 if (ret) 568 goto err_clk; 569 } 570 571 err_clk: 572 mutex_unlock(&input_dev->mutex); 573 574 return ret; 575 } 576 577 static SIMPLE_DEV_PM_OPS(imx_kbd_pm_ops, imx_kbd_suspend, imx_kbd_resume); 578 579 static struct platform_driver imx_keypad_driver = { 580 .driver = { 581 .name = "imx-keypad", 582 .pm = &imx_kbd_pm_ops, 583 .of_match_table = of_match_ptr(imx_keypad_of_match), 584 }, 585 .probe = imx_keypad_probe, 586 }; 587 module_platform_driver(imx_keypad_driver); 588 589 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>"); 590 MODULE_DESCRIPTION("IMX Keypad Port Driver"); 591 MODULE_LICENSE("GPL v2"); 592 MODULE_ALIAS("platform:imx-keypad"); 593