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