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. */
imx_keypad_scan_matrix(struct imx_keypad * keypad,unsigned short * 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 */
imx_keypad_fire_events(struct imx_keypad * keypad,unsigned short * matrix_volatile_state)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 */
imx_keypad_check_for_events(struct timer_list * t)184 static 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
imx_keypad_irq_handler(int irq,void * dev_id)288 static 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
imx_keypad_config(struct imx_keypad * keypad)313 static 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
imx_keypad_inhibit(struct imx_keypad * keypad)349 static 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
imx_keypad_close(struct input_dev * dev)364 static 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
imx_keypad_open(struct input_dev * dev)381 static 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
407 open_err:
408 imx_keypad_close(dev);
409 return -EIO;
410 }
411
412 static const struct of_device_id imx_keypad_of_match[] = {
413 { .compatible = "fsl,imx21-kpp", },
414 { /* sentinel */ }
415 };
416 MODULE_DEVICE_TABLE(of, imx_keypad_of_match);
417
imx_keypad_probe(struct platform_device * pdev)418 static 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
imx_kbd_noirq_suspend(struct device * dev)517 static 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
imx_kbd_noirq_resume(struct device * dev)545 static 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
563 err_clk:
564 mutex_unlock(&input_dev->mutex);
565
566 return ret;
567 }
568
569 static 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
573 static 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 };
581 module_platform_driver(imx_keypad_driver);
582
583 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
584 MODULE_DESCRIPTION("IMX Keypad Port Driver");
585 MODULE_LICENSE("GPL v2");
586 MODULE_ALIAS("platform:imx-keypad");
587