xref: /linux/drivers/input/keyboard/matrix_keypad.c (revision 702648721db590b3425c31ade294000e18808345) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  GPIO driven matrix keyboard driver
4  *
5  *  Copyright (c) 2008 Marek Vasut <marek.vasut@gmail.com>
6  *
7  *  Based on corgikbd.c
8  */
9 
10 #include <linux/types.h>
11 #include <linux/delay.h>
12 #include <linux/gpio/consumer.h>
13 #include <linux/platform_device.h>
14 #include <linux/input.h>
15 #include <linux/irq.h>
16 #include <linux/interrupt.h>
17 #include <linux/jiffies.h>
18 #include <linux/module.h>
19 #include <linux/gpio.h>
20 #include <linux/input/matrix_keypad.h>
21 #include <linux/slab.h>
22 #include <linux/of.h>
23 #include <linux/of_gpio.h>
24 #include <linux/of_platform.h>
25 
26 struct matrix_keypad {
27 	const struct matrix_keypad_platform_data *pdata;
28 	struct input_dev *input_dev;
29 	unsigned int row_shift;
30 
31 	DECLARE_BITMAP(disabled_gpios, MATRIX_MAX_ROWS);
32 
33 	uint32_t last_key_state[MATRIX_MAX_COLS];
34 	struct delayed_work work;
35 	spinlock_t lock;
36 	bool scan_pending;
37 	bool stopped;
38 	bool gpio_all_disabled;
39 };
40 
41 /*
42  * NOTE: If drive_inactive_cols is false, then the GPIO has to be put into
43  * HiZ when de-activated to cause minmal side effect when scanning other
44  * columns. In that case it is configured here to be input, otherwise it is
45  * driven with the inactive value.
46  */
47 static void __activate_col(const struct matrix_keypad_platform_data *pdata,
48 			   int col, bool on)
49 {
50 	bool level_on = !pdata->active_low;
51 
52 	if (on) {
53 		gpio_direction_output(pdata->col_gpios[col], level_on);
54 	} else {
55 		gpio_set_value_cansleep(pdata->col_gpios[col], !level_on);
56 		if (!pdata->drive_inactive_cols)
57 			gpio_direction_input(pdata->col_gpios[col]);
58 	}
59 }
60 
61 static void activate_col(const struct matrix_keypad_platform_data *pdata,
62 			 int col, bool on)
63 {
64 	__activate_col(pdata, col, on);
65 
66 	if (on && pdata->col_scan_delay_us)
67 		udelay(pdata->col_scan_delay_us);
68 }
69 
70 static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
71 			      bool on)
72 {
73 	int col;
74 
75 	for (col = 0; col < pdata->num_col_gpios; col++)
76 		__activate_col(pdata, col, on);
77 }
78 
79 static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
80 			 int row)
81 {
82 	return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
83 			!pdata->active_low : pdata->active_low;
84 }
85 
86 static void enable_row_irqs(struct matrix_keypad *keypad)
87 {
88 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
89 	int i;
90 
91 	if (pdata->clustered_irq > 0)
92 		enable_irq(pdata->clustered_irq);
93 	else {
94 		for (i = 0; i < pdata->num_row_gpios; i++)
95 			enable_irq(gpio_to_irq(pdata->row_gpios[i]));
96 	}
97 }
98 
99 static void disable_row_irqs(struct matrix_keypad *keypad)
100 {
101 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
102 	int i;
103 
104 	if (pdata->clustered_irq > 0)
105 		disable_irq_nosync(pdata->clustered_irq);
106 	else {
107 		for (i = 0; i < pdata->num_row_gpios; i++)
108 			disable_irq_nosync(gpio_to_irq(pdata->row_gpios[i]));
109 	}
110 }
111 
112 /*
113  * This gets the keys from keyboard and reports it to input subsystem
114  */
115 static void matrix_keypad_scan(struct work_struct *work)
116 {
117 	struct matrix_keypad *keypad =
118 		container_of(work, struct matrix_keypad, work.work);
119 	struct input_dev *input_dev = keypad->input_dev;
120 	const unsigned short *keycodes = input_dev->keycode;
121 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
122 	uint32_t new_state[MATRIX_MAX_COLS];
123 	int row, col, code;
124 
125 	/* de-activate all columns for scanning */
126 	activate_all_cols(pdata, false);
127 
128 	memset(new_state, 0, sizeof(new_state));
129 
130 	for (row = 0; row < pdata->num_row_gpios; row++)
131 		gpio_direction_input(pdata->row_gpios[row]);
132 
133 	/* assert each column and read the row status out */
134 	for (col = 0; col < pdata->num_col_gpios; col++) {
135 
136 		activate_col(pdata, col, true);
137 
138 		for (row = 0; row < pdata->num_row_gpios; row++)
139 			new_state[col] |=
140 				row_asserted(pdata, row) ? (1 << row) : 0;
141 
142 		activate_col(pdata, col, false);
143 	}
144 
145 	for (col = 0; col < pdata->num_col_gpios; col++) {
146 		uint32_t bits_changed;
147 
148 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
149 		if (bits_changed == 0)
150 			continue;
151 
152 		for (row = 0; row < pdata->num_row_gpios; row++) {
153 			if ((bits_changed & (1 << row)) == 0)
154 				continue;
155 
156 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
157 			input_event(input_dev, EV_MSC, MSC_SCAN, code);
158 			input_report_key(input_dev,
159 					 keycodes[code],
160 					 new_state[col] & (1 << row));
161 		}
162 	}
163 	input_sync(input_dev);
164 
165 	memcpy(keypad->last_key_state, new_state, sizeof(new_state));
166 
167 	activate_all_cols(pdata, true);
168 
169 	/* Enable IRQs again */
170 	spin_lock_irq(&keypad->lock);
171 	keypad->scan_pending = false;
172 	enable_row_irqs(keypad);
173 	spin_unlock_irq(&keypad->lock);
174 }
175 
176 static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
177 {
178 	struct matrix_keypad *keypad = id;
179 	unsigned long flags;
180 
181 	spin_lock_irqsave(&keypad->lock, flags);
182 
183 	/*
184 	 * See if another IRQ beaten us to it and scheduled the
185 	 * scan already. In that case we should not try to
186 	 * disable IRQs again.
187 	 */
188 	if (unlikely(keypad->scan_pending || keypad->stopped))
189 		goto out;
190 
191 	disable_row_irqs(keypad);
192 	keypad->scan_pending = true;
193 	schedule_delayed_work(&keypad->work,
194 		msecs_to_jiffies(keypad->pdata->debounce_ms));
195 
196 out:
197 	spin_unlock_irqrestore(&keypad->lock, flags);
198 	return IRQ_HANDLED;
199 }
200 
201 static int matrix_keypad_start(struct input_dev *dev)
202 {
203 	struct matrix_keypad *keypad = input_get_drvdata(dev);
204 
205 	keypad->stopped = false;
206 	mb();
207 
208 	/*
209 	 * Schedule an immediate key scan to capture current key state;
210 	 * columns will be activated and IRQs be enabled after the scan.
211 	 */
212 	schedule_delayed_work(&keypad->work, 0);
213 
214 	return 0;
215 }
216 
217 static void matrix_keypad_stop(struct input_dev *dev)
218 {
219 	struct matrix_keypad *keypad = input_get_drvdata(dev);
220 
221 	spin_lock_irq(&keypad->lock);
222 	keypad->stopped = true;
223 	spin_unlock_irq(&keypad->lock);
224 
225 	flush_delayed_work(&keypad->work);
226 	/*
227 	 * matrix_keypad_scan() will leave IRQs enabled;
228 	 * we should disable them now.
229 	 */
230 	disable_row_irqs(keypad);
231 }
232 
233 static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
234 {
235 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
236 	unsigned int gpio;
237 	int i;
238 
239 	if (pdata->clustered_irq > 0) {
240 		if (enable_irq_wake(pdata->clustered_irq) == 0)
241 			keypad->gpio_all_disabled = true;
242 	} else {
243 
244 		for (i = 0; i < pdata->num_row_gpios; i++) {
245 			if (!test_bit(i, keypad->disabled_gpios)) {
246 				gpio = pdata->row_gpios[i];
247 
248 				if (enable_irq_wake(gpio_to_irq(gpio)) == 0)
249 					__set_bit(i, keypad->disabled_gpios);
250 			}
251 		}
252 	}
253 }
254 
255 static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
256 {
257 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
258 	unsigned int gpio;
259 	int i;
260 
261 	if (pdata->clustered_irq > 0) {
262 		if (keypad->gpio_all_disabled) {
263 			disable_irq_wake(pdata->clustered_irq);
264 			keypad->gpio_all_disabled = false;
265 		}
266 	} else {
267 		for (i = 0; i < pdata->num_row_gpios; i++) {
268 			if (test_and_clear_bit(i, keypad->disabled_gpios)) {
269 				gpio = pdata->row_gpios[i];
270 				disable_irq_wake(gpio_to_irq(gpio));
271 			}
272 		}
273 	}
274 }
275 
276 static int matrix_keypad_suspend(struct device *dev)
277 {
278 	struct platform_device *pdev = to_platform_device(dev);
279 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
280 
281 	matrix_keypad_stop(keypad->input_dev);
282 
283 	if (device_may_wakeup(&pdev->dev))
284 		matrix_keypad_enable_wakeup(keypad);
285 
286 	return 0;
287 }
288 
289 static int matrix_keypad_resume(struct device *dev)
290 {
291 	struct platform_device *pdev = to_platform_device(dev);
292 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
293 
294 	if (device_may_wakeup(&pdev->dev))
295 		matrix_keypad_disable_wakeup(keypad);
296 
297 	matrix_keypad_start(keypad->input_dev);
298 
299 	return 0;
300 }
301 
302 static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
303 				matrix_keypad_suspend, matrix_keypad_resume);
304 
305 static int matrix_keypad_init_gpio(struct platform_device *pdev,
306 				   struct matrix_keypad *keypad)
307 {
308 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
309 	int i, err;
310 
311 	/* initialized strobe lines as outputs, activated */
312 	for (i = 0; i < pdata->num_col_gpios; i++) {
313 		err = gpio_request(pdata->col_gpios[i], "matrix_kbd_col");
314 		if (err) {
315 			dev_err(&pdev->dev,
316 				"failed to request GPIO%d for COL%d\n",
317 				pdata->col_gpios[i], i);
318 			goto err_free_cols;
319 		}
320 
321 		gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
322 	}
323 
324 	for (i = 0; i < pdata->num_row_gpios; i++) {
325 		err = gpio_request(pdata->row_gpios[i], "matrix_kbd_row");
326 		if (err) {
327 			dev_err(&pdev->dev,
328 				"failed to request GPIO%d for ROW%d\n",
329 				pdata->row_gpios[i], i);
330 			goto err_free_rows;
331 		}
332 
333 		gpio_direction_input(pdata->row_gpios[i]);
334 	}
335 
336 	if (pdata->clustered_irq > 0) {
337 		err = request_any_context_irq(pdata->clustered_irq,
338 				matrix_keypad_interrupt,
339 				pdata->clustered_irq_flags,
340 				"matrix-keypad", keypad);
341 		if (err < 0) {
342 			dev_err(&pdev->dev,
343 				"Unable to acquire clustered interrupt\n");
344 			goto err_free_rows;
345 		}
346 	} else {
347 		for (i = 0; i < pdata->num_row_gpios; i++) {
348 			err = request_any_context_irq(
349 					gpio_to_irq(pdata->row_gpios[i]),
350 					matrix_keypad_interrupt,
351 					IRQF_TRIGGER_RISING |
352 					IRQF_TRIGGER_FALLING,
353 					"matrix-keypad", keypad);
354 			if (err < 0) {
355 				dev_err(&pdev->dev,
356 					"Unable to acquire interrupt for GPIO line %i\n",
357 					pdata->row_gpios[i]);
358 				goto err_free_irqs;
359 			}
360 		}
361 	}
362 
363 	/* initialized as disabled - enabled by input->open */
364 	disable_row_irqs(keypad);
365 	return 0;
366 
367 err_free_irqs:
368 	while (--i >= 0)
369 		free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
370 	i = pdata->num_row_gpios;
371 err_free_rows:
372 	while (--i >= 0)
373 		gpio_free(pdata->row_gpios[i]);
374 	i = pdata->num_col_gpios;
375 err_free_cols:
376 	while (--i >= 0)
377 		gpio_free(pdata->col_gpios[i]);
378 
379 	return err;
380 }
381 
382 static void matrix_keypad_free_gpio(struct matrix_keypad *keypad)
383 {
384 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
385 	int i;
386 
387 	if (pdata->clustered_irq > 0) {
388 		free_irq(pdata->clustered_irq, keypad);
389 	} else {
390 		for (i = 0; i < pdata->num_row_gpios; i++)
391 			free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
392 	}
393 
394 	for (i = 0; i < pdata->num_row_gpios; i++)
395 		gpio_free(pdata->row_gpios[i]);
396 
397 	for (i = 0; i < pdata->num_col_gpios; i++)
398 		gpio_free(pdata->col_gpios[i]);
399 }
400 
401 #ifdef CONFIG_OF
402 static struct matrix_keypad_platform_data *
403 matrix_keypad_parse_dt(struct device *dev)
404 {
405 	struct matrix_keypad_platform_data *pdata;
406 	struct device_node *np = dev->of_node;
407 	unsigned int *gpios;
408 	int ret, i, nrow, ncol;
409 
410 	if (!np) {
411 		dev_err(dev, "device lacks DT data\n");
412 		return ERR_PTR(-ENODEV);
413 	}
414 
415 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
416 	if (!pdata) {
417 		dev_err(dev, "could not allocate memory for platform data\n");
418 		return ERR_PTR(-ENOMEM);
419 	}
420 
421 	pdata->num_row_gpios = nrow = gpiod_count(dev, "row");
422 	pdata->num_col_gpios = ncol = gpiod_count(dev, "col");
423 	if (nrow < 0 || ncol < 0) {
424 		dev_err(dev, "number of keypad rows/columns not specified\n");
425 		return ERR_PTR(-EINVAL);
426 	}
427 
428 	pdata->no_autorepeat = of_property_read_bool(np, "linux,no-autorepeat");
429 
430 	pdata->wakeup = of_property_read_bool(np, "wakeup-source") ||
431 			of_property_read_bool(np, "linux,wakeup"); /* legacy */
432 
433 	pdata->active_low = of_property_read_bool(np, "gpio-activelow");
434 
435 	pdata->drive_inactive_cols =
436 		of_property_read_bool(np, "drive-inactive-cols");
437 
438 	of_property_read_u32(np, "debounce-delay-ms", &pdata->debounce_ms);
439 	of_property_read_u32(np, "col-scan-delay-us",
440 						&pdata->col_scan_delay_us);
441 
442 	gpios = devm_kcalloc(dev,
443 			     pdata->num_row_gpios + pdata->num_col_gpios,
444 			     sizeof(unsigned int),
445 			     GFP_KERNEL);
446 	if (!gpios) {
447 		dev_err(dev, "could not allocate memory for gpios\n");
448 		return ERR_PTR(-ENOMEM);
449 	}
450 
451 	for (i = 0; i < nrow; i++) {
452 		ret = of_get_named_gpio(np, "row-gpios", i);
453 		if (ret < 0)
454 			return ERR_PTR(ret);
455 		gpios[i] = ret;
456 	}
457 
458 	for (i = 0; i < ncol; i++) {
459 		ret = of_get_named_gpio(np, "col-gpios", i);
460 		if (ret < 0)
461 			return ERR_PTR(ret);
462 		gpios[nrow + i] = ret;
463 	}
464 
465 	pdata->row_gpios = gpios;
466 	pdata->col_gpios = &gpios[pdata->num_row_gpios];
467 
468 	return pdata;
469 }
470 #else
471 static inline struct matrix_keypad_platform_data *
472 matrix_keypad_parse_dt(struct device *dev)
473 {
474 	dev_err(dev, "no platform data defined\n");
475 
476 	return ERR_PTR(-EINVAL);
477 }
478 #endif
479 
480 static int matrix_keypad_probe(struct platform_device *pdev)
481 {
482 	const struct matrix_keypad_platform_data *pdata;
483 	struct matrix_keypad *keypad;
484 	struct input_dev *input_dev;
485 	int err;
486 
487 	pdata = dev_get_platdata(&pdev->dev);
488 	if (!pdata) {
489 		pdata = matrix_keypad_parse_dt(&pdev->dev);
490 		if (IS_ERR(pdata))
491 			return PTR_ERR(pdata);
492 	} else if (!pdata->keymap_data) {
493 		dev_err(&pdev->dev, "no keymap data defined\n");
494 		return -EINVAL;
495 	}
496 
497 	keypad = kzalloc(sizeof(struct matrix_keypad), GFP_KERNEL);
498 	input_dev = input_allocate_device();
499 	if (!keypad || !input_dev) {
500 		err = -ENOMEM;
501 		goto err_free_mem;
502 	}
503 
504 	keypad->input_dev = input_dev;
505 	keypad->pdata = pdata;
506 	keypad->row_shift = get_count_order(pdata->num_col_gpios);
507 	keypad->stopped = true;
508 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
509 	spin_lock_init(&keypad->lock);
510 
511 	input_dev->name		= pdev->name;
512 	input_dev->id.bustype	= BUS_HOST;
513 	input_dev->dev.parent	= &pdev->dev;
514 	input_dev->open		= matrix_keypad_start;
515 	input_dev->close	= matrix_keypad_stop;
516 
517 	err = matrix_keypad_build_keymap(pdata->keymap_data, NULL,
518 					 pdata->num_row_gpios,
519 					 pdata->num_col_gpios,
520 					 NULL, input_dev);
521 	if (err) {
522 		dev_err(&pdev->dev, "failed to build keymap\n");
523 		goto err_free_mem;
524 	}
525 
526 	if (!pdata->no_autorepeat)
527 		__set_bit(EV_REP, input_dev->evbit);
528 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
529 	input_set_drvdata(input_dev, keypad);
530 
531 	err = matrix_keypad_init_gpio(pdev, keypad);
532 	if (err)
533 		goto err_free_mem;
534 
535 	err = input_register_device(keypad->input_dev);
536 	if (err)
537 		goto err_free_gpio;
538 
539 	device_init_wakeup(&pdev->dev, pdata->wakeup);
540 	platform_set_drvdata(pdev, keypad);
541 
542 	return 0;
543 
544 err_free_gpio:
545 	matrix_keypad_free_gpio(keypad);
546 err_free_mem:
547 	input_free_device(input_dev);
548 	kfree(keypad);
549 	return err;
550 }
551 
552 static int matrix_keypad_remove(struct platform_device *pdev)
553 {
554 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
555 
556 	matrix_keypad_free_gpio(keypad);
557 	input_unregister_device(keypad->input_dev);
558 	kfree(keypad);
559 
560 	return 0;
561 }
562 
563 #ifdef CONFIG_OF
564 static const struct of_device_id matrix_keypad_dt_match[] = {
565 	{ .compatible = "gpio-matrix-keypad" },
566 	{ }
567 };
568 MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
569 #endif
570 
571 static struct platform_driver matrix_keypad_driver = {
572 	.probe		= matrix_keypad_probe,
573 	.remove		= matrix_keypad_remove,
574 	.driver		= {
575 		.name	= "matrix-keypad",
576 		.pm	= pm_sleep_ptr(&matrix_keypad_pm_ops),
577 		.of_match_table = of_match_ptr(matrix_keypad_dt_match),
578 	},
579 };
580 module_platform_driver(matrix_keypad_driver);
581 
582 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
583 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
584 MODULE_LICENSE("GPL v2");
585 MODULE_ALIAS("platform:matrix-keypad");
586