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 45 struct 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. */ 79 static 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 */ 144 static 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 */ 184 static void imx_keypad_check_for_events(struct timer_list *t) 185 { 186 struct imx_keypad *keypad = timer_container_of(keypad, t, 187 check_matrix_timer); 188 unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS]; 189 unsigned short reg_val; 190 bool state_changed, is_zero_matrix; 191 int i; 192 193 memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state)); 194 195 imx_keypad_scan_matrix(keypad, matrix_volatile_state); 196 197 state_changed = false; 198 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 199 if ((keypad->cols_en_mask & (1 << i)) == 0) 200 continue; 201 202 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) { 203 state_changed = true; 204 break; 205 } 206 } 207 208 /* 209 * If the matrix state is changed from the previous scan 210 * (Re)Begin the debouncing process, saving the new state in 211 * keypad->matrix_unstable_state. 212 * else 213 * Increase the count of number of scans with a stable state. 214 */ 215 if (state_changed) { 216 memcpy(keypad->matrix_unstable_state, matrix_volatile_state, 217 sizeof(matrix_volatile_state)); 218 keypad->stable_count = 0; 219 } else 220 keypad->stable_count++; 221 222 /* 223 * If the matrix is not as stable as we want reschedule scan 224 * in the near future. 225 */ 226 if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) { 227 mod_timer(&keypad->check_matrix_timer, 228 jiffies + msecs_to_jiffies(10)); 229 return; 230 } 231 232 /* 233 * If the matrix state is stable, fire the events and save the new 234 * stable state. Note, if the matrix is kept stable for longer 235 * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all 236 * events have already been generated. 237 */ 238 if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) { 239 imx_keypad_fire_events(keypad, matrix_volatile_state); 240 241 memcpy(keypad->matrix_stable_state, matrix_volatile_state, 242 sizeof(matrix_volatile_state)); 243 } 244 245 is_zero_matrix = true; 246 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) { 247 if (matrix_volatile_state[i] != 0) { 248 is_zero_matrix = false; 249 break; 250 } 251 } 252 253 254 if (is_zero_matrix) { 255 /* 256 * All keys have been released. Enable only the KDI 257 * interrupt for future key presses (clear the KDI 258 * status bit and its sync chain before that). 259 */ 260 reg_val = readw(keypad->mmio_base + KPSR); 261 reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC; 262 writew(reg_val, keypad->mmio_base + KPSR); 263 264 reg_val = readw(keypad->mmio_base + KPSR); 265 reg_val |= KBD_STAT_KDIE; 266 reg_val &= ~KBD_STAT_KRIE; 267 writew(reg_val, keypad->mmio_base + KPSR); 268 } else { 269 /* 270 * Some keys are still pressed. Schedule a rescan in 271 * attempt to detect multiple key presses and enable 272 * the KRI interrupt to react quickly to key release 273 * event. 274 */ 275 mod_timer(&keypad->check_matrix_timer, 276 jiffies + msecs_to_jiffies(60)); 277 278 reg_val = readw(keypad->mmio_base + KPSR); 279 reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS; 280 writew(reg_val, keypad->mmio_base + KPSR); 281 282 reg_val = readw(keypad->mmio_base + KPSR); 283 reg_val |= KBD_STAT_KRIE; 284 reg_val &= ~KBD_STAT_KDIE; 285 writew(reg_val, keypad->mmio_base + KPSR); 286 } 287 } 288 289 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id) 290 { 291 struct imx_keypad *keypad = dev_id; 292 unsigned short reg_val; 293 294 reg_val = readw(keypad->mmio_base + KPSR); 295 296 /* Disable both interrupt types */ 297 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 298 /* Clear interrupts status bits */ 299 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 300 writew(reg_val, keypad->mmio_base + KPSR); 301 302 if (keypad->enabled) { 303 /* The matrix is supposed to be changed */ 304 keypad->stable_count = 0; 305 306 /* Schedule the scanning procedure near in the future */ 307 mod_timer(&keypad->check_matrix_timer, 308 jiffies + msecs_to_jiffies(2)); 309 } 310 311 return IRQ_HANDLED; 312 } 313 314 static void imx_keypad_config(struct imx_keypad *keypad) 315 { 316 unsigned short reg_val; 317 318 /* 319 * Include enabled rows in interrupt generation (KPCR[7:0]) 320 * Configure keypad columns as open-drain (KPCR[15:8]) 321 */ 322 reg_val = readw(keypad->mmio_base + KPCR); 323 reg_val |= keypad->rows_en_mask & 0xff; /* rows */ 324 reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */ 325 writew(reg_val, keypad->mmio_base + KPCR); 326 327 /* Write 0's to KPDR[15:8] (Colums) */ 328 reg_val = readw(keypad->mmio_base + KPDR); 329 reg_val &= 0x00ff; 330 writew(reg_val, keypad->mmio_base + KPDR); 331 332 /* Configure columns as output, rows as input (KDDR[15:0]) */ 333 writew(0xff00, keypad->mmio_base + KDDR); 334 335 /* 336 * Clear Key Depress and Key Release status bit. 337 * Clear both synchronizer chain. 338 */ 339 reg_val = readw(keypad->mmio_base + KPSR); 340 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD | 341 KBD_STAT_KDSC | KBD_STAT_KRSS; 342 writew(reg_val, keypad->mmio_base + KPSR); 343 344 /* Enable KDI and disable KRI (avoid false release events). */ 345 reg_val |= KBD_STAT_KDIE; 346 reg_val &= ~KBD_STAT_KRIE; 347 writew(reg_val, keypad->mmio_base + KPSR); 348 } 349 350 static void imx_keypad_inhibit(struct imx_keypad *keypad) 351 { 352 unsigned short reg_val; 353 354 /* Inhibit KDI and KRI interrupts. */ 355 reg_val = readw(keypad->mmio_base + KPSR); 356 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE); 357 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD; 358 writew(reg_val, keypad->mmio_base + KPSR); 359 360 /* Colums as open drain and disable all rows */ 361 reg_val = (keypad->cols_en_mask & 0xff) << 8; 362 writew(reg_val, keypad->mmio_base + KPCR); 363 } 364 365 static void imx_keypad_close(struct input_dev *dev) 366 { 367 struct imx_keypad *keypad = input_get_drvdata(dev); 368 369 dev_dbg(&dev->dev, ">%s\n", __func__); 370 371 /* Mark keypad as being inactive */ 372 keypad->enabled = false; 373 synchronize_irq(keypad->irq); 374 timer_delete_sync(&keypad->check_matrix_timer); 375 376 imx_keypad_inhibit(keypad); 377 378 /* Disable clock unit */ 379 clk_disable_unprepare(keypad->clk); 380 } 381 382 static int imx_keypad_open(struct input_dev *dev) 383 { 384 struct imx_keypad *keypad = input_get_drvdata(dev); 385 int error; 386 387 dev_dbg(&dev->dev, ">%s\n", __func__); 388 389 /* Enable the kpp clock */ 390 error = clk_prepare_enable(keypad->clk); 391 if (error) 392 return error; 393 394 /* We became active from now */ 395 keypad->enabled = true; 396 397 imx_keypad_config(keypad); 398 399 /* Sanity control, not all the rows must be actived now. */ 400 if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) { 401 dev_err(&dev->dev, 402 "too many keys pressed, control pins initialisation\n"); 403 goto open_err; 404 } 405 406 return 0; 407 408 open_err: 409 imx_keypad_close(dev); 410 return -EIO; 411 } 412 413 static const struct of_device_id imx_keypad_of_match[] = { 414 { .compatible = "fsl,imx21-kpp", }, 415 { /* sentinel */ } 416 }; 417 MODULE_DEVICE_TABLE(of, imx_keypad_of_match); 418 419 static int imx_keypad_probe(struct platform_device *pdev) 420 { 421 struct imx_keypad *keypad; 422 struct input_dev *input_dev; 423 int irq, error, i, row, col; 424 425 irq = platform_get_irq(pdev, 0); 426 if (irq < 0) 427 return irq; 428 429 input_dev = devm_input_allocate_device(&pdev->dev); 430 if (!input_dev) { 431 dev_err(&pdev->dev, "failed to allocate the input device\n"); 432 return -ENOMEM; 433 } 434 435 keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL); 436 if (!keypad) { 437 dev_err(&pdev->dev, "not enough memory for driver data\n"); 438 return -ENOMEM; 439 } 440 441 keypad->input_dev = input_dev; 442 keypad->irq = irq; 443 keypad->stable_count = 0; 444 445 timer_setup(&keypad->check_matrix_timer, 446 imx_keypad_check_for_events, 0); 447 448 keypad->mmio_base = devm_platform_ioremap_resource(pdev, 0); 449 if (IS_ERR(keypad->mmio_base)) 450 return PTR_ERR(keypad->mmio_base); 451 452 keypad->clk = devm_clk_get(&pdev->dev, NULL); 453 if (IS_ERR(keypad->clk)) { 454 dev_err(&pdev->dev, "failed to get keypad clock\n"); 455 return PTR_ERR(keypad->clk); 456 } 457 458 /* Init the Input device */ 459 input_dev->name = pdev->name; 460 input_dev->id.bustype = BUS_HOST; 461 input_dev->dev.parent = &pdev->dev; 462 input_dev->open = imx_keypad_open; 463 input_dev->close = imx_keypad_close; 464 465 error = matrix_keypad_build_keymap(NULL, NULL, 466 MAX_MATRIX_KEY_ROWS, 467 MAX_MATRIX_KEY_COLS, 468 keypad->keycodes, input_dev); 469 if (error) { 470 dev_err(&pdev->dev, "failed to build keymap\n"); 471 return error; 472 } 473 474 /* Search for rows and cols enabled */ 475 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) { 476 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) { 477 i = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT); 478 if (keypad->keycodes[i] != KEY_RESERVED) { 479 keypad->rows_en_mask |= 1 << row; 480 keypad->cols_en_mask |= 1 << col; 481 } 482 } 483 } 484 dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask); 485 dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask); 486 487 __set_bit(EV_REP, input_dev->evbit); 488 input_set_capability(input_dev, EV_MSC, MSC_SCAN); 489 input_set_drvdata(input_dev, keypad); 490 491 /* Ensure that the keypad will stay dormant until opened */ 492 error = clk_prepare_enable(keypad->clk); 493 if (error) 494 return error; 495 imx_keypad_inhibit(keypad); 496 clk_disable_unprepare(keypad->clk); 497 498 error = devm_request_irq(&pdev->dev, irq, imx_keypad_irq_handler, 0, 499 pdev->name, keypad); 500 if (error) { 501 dev_err(&pdev->dev, "failed to request IRQ\n"); 502 return error; 503 } 504 505 /* Register the input device */ 506 error = input_register_device(input_dev); 507 if (error) { 508 dev_err(&pdev->dev, "failed to register input device\n"); 509 return error; 510 } 511 512 platform_set_drvdata(pdev, keypad); 513 device_init_wakeup(&pdev->dev, 1); 514 515 return 0; 516 } 517 518 static int __maybe_unused imx_kbd_noirq_suspend(struct device *dev) 519 { 520 struct platform_device *pdev = to_platform_device(dev); 521 struct imx_keypad *kbd = platform_get_drvdata(pdev); 522 struct input_dev *input_dev = kbd->input_dev; 523 unsigned short reg_val = readw(kbd->mmio_base + KPSR); 524 525 scoped_guard(mutex, &input_dev->mutex) { 526 /* imx kbd can wake up system even clock is disabled */ 527 if (input_device_enabled(input_dev)) 528 clk_disable_unprepare(kbd->clk); 529 } 530 531 if (device_may_wakeup(&pdev->dev)) { 532 if (reg_val & KBD_STAT_KPKD) 533 reg_val |= KBD_STAT_KRIE; 534 if (reg_val & KBD_STAT_KPKR) 535 reg_val |= KBD_STAT_KDIE; 536 writew(reg_val, kbd->mmio_base + KPSR); 537 538 enable_irq_wake(kbd->irq); 539 } 540 541 return 0; 542 } 543 544 static int __maybe_unused imx_kbd_noirq_resume(struct device *dev) 545 { 546 struct platform_device *pdev = to_platform_device(dev); 547 struct imx_keypad *kbd = platform_get_drvdata(pdev); 548 struct input_dev *input_dev = kbd->input_dev; 549 int error; 550 551 if (device_may_wakeup(&pdev->dev)) 552 disable_irq_wake(kbd->irq); 553 554 guard(mutex)(&input_dev->mutex); 555 556 if (input_device_enabled(input_dev)) { 557 error = clk_prepare_enable(kbd->clk); 558 if (error) 559 return error; 560 } 561 562 return 0; 563 } 564 565 static const struct dev_pm_ops imx_kbd_pm_ops = { 566 SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_kbd_noirq_suspend, imx_kbd_noirq_resume) 567 }; 568 569 static struct platform_driver imx_keypad_driver = { 570 .driver = { 571 .name = "imx-keypad", 572 .pm = &imx_kbd_pm_ops, 573 .of_match_table = imx_keypad_of_match, 574 }, 575 .probe = imx_keypad_probe, 576 }; 577 module_platform_driver(imx_keypad_driver); 578 579 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>"); 580 MODULE_DESCRIPTION("IMX Keypad Port Driver"); 581 MODULE_LICENSE("GPL v2"); 582 MODULE_ALIAS("platform:imx-keypad"); 583