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