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