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

Warning: That file was not part of the compilation database. It may have many parsing errors.