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: If drive_inactive_cols is false, then the GPIO has to be put into
46  * HiZ when de-activated to cause minmal side effect when scanning other
47  * columns. In that case it is configured here to be input, otherwise it is
48  * driven with the inactive value.
49  */
50 static void __activate_col(const struct matrix_keypad_platform_data *pdata,
51 			   int col, bool on)
52 {
53 	bool level_on = !pdata->active_low;
54 
55 	if (on) {
56 		gpio_direction_output(pdata->col_gpios[col], level_on);
57 	} else {
58 		gpio_set_value_cansleep(pdata->col_gpios[col], !level_on);
59 		if (!pdata->drive_inactive_cols)
60 			gpio_direction_input(pdata->col_gpios[col]);
61 	}
62 }
63 
64 static void activate_col(const struct matrix_keypad_platform_data *pdata,
65 			 int col, bool on)
66 {
67 	__activate_col(pdata, col, on);
68 
69 	if (on && pdata->col_scan_delay_us)
70 		udelay(pdata->col_scan_delay_us);
71 }
72 
73 static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
74 			      bool on)
75 {
76 	int col;
77 
78 	for (col = 0; col < pdata->num_col_gpios; col++)
79 		__activate_col(pdata, col, on);
80 }
81 
82 static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
83 			 int row)
84 {
85 	return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
86 			!pdata->active_low : pdata->active_low;
87 }
88 
89 static void enable_row_irqs(struct matrix_keypad *keypad)
90 {
91 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
92 	int i;
93 
94 	if (pdata->clustered_irq > 0)
95 		enable_irq(pdata->clustered_irq);
96 	else {
97 		for (i = 0; i < pdata->num_row_gpios; i++)
98 			enable_irq(gpio_to_irq(pdata->row_gpios[i]));
99 	}
100 }
101 
102 static void disable_row_irqs(struct matrix_keypad *keypad)
103 {
104 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
105 	int i;
106 
107 	if (pdata->clustered_irq > 0)
108 		disable_irq_nosync(pdata->clustered_irq);
109 	else {
110 		for (i = 0; i < pdata->num_row_gpios; i++)
111 			disable_irq_nosync(gpio_to_irq(pdata->row_gpios[i]));
112 	}
113 }
114 
115 /*
116  * This gets the keys from keyboard and reports it to input subsystem
117  */
118 static void matrix_keypad_scan(struct work_struct *work)
119 {
120 	struct matrix_keypad *keypad =
121 		container_of(work, struct matrix_keypad, work.work);
122 	struct input_dev *input_dev = keypad->input_dev;
123 	const unsigned short *keycodes = input_dev->keycode;
124 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
125 	uint32_t new_state[MATRIX_MAX_COLS];
126 	int row, col, code;
127 
128 	/* de-activate all columns for scanning */
129 	activate_all_cols(pdata, false);
130 
131 	memset(new_state, 0, sizeof(new_state));
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_work(&keypad->work.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 #ifdef CONFIG_PM_SLEEP
234 static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
235 {
236 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
237 	unsigned int gpio;
238 	int i;
239 
240 	if (pdata->clustered_irq > 0) {
241 		if (enable_irq_wake(pdata->clustered_irq) == 0)
242 			keypad->gpio_all_disabled = true;
243 	} else {
244 
245 		for (i = 0; i < pdata->num_row_gpios; i++) {
246 			if (!test_bit(i, keypad->disabled_gpios)) {
247 				gpio = pdata->row_gpios[i];
248 
249 				if (enable_irq_wake(gpio_to_irq(gpio)) == 0)
250 					__set_bit(i, keypad->disabled_gpios);
251 			}
252 		}
253 	}
254 }
255 
256 static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
257 {
258 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
259 	unsigned int gpio;
260 	int i;
261 
262 	if (pdata->clustered_irq > 0) {
263 		if (keypad->gpio_all_disabled) {
264 			disable_irq_wake(pdata->clustered_irq);
265 			keypad->gpio_all_disabled = false;
266 		}
267 	} else {
268 		for (i = 0; i < pdata->num_row_gpios; i++) {
269 			if (test_and_clear_bit(i, keypad->disabled_gpios)) {
270 				gpio = pdata->row_gpios[i];
271 				disable_irq_wake(gpio_to_irq(gpio));
272 			}
273 		}
274 	}
275 }
276 
277 static int matrix_keypad_suspend(struct device *dev)
278 {
279 	struct platform_device *pdev = to_platform_device(dev);
280 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
281 
282 	matrix_keypad_stop(keypad->input_dev);
283 
284 	if (device_may_wakeup(&pdev->dev))
285 		matrix_keypad_enable_wakeup(keypad);
286 
287 	return 0;
288 }
289 
290 static int matrix_keypad_resume(struct device *dev)
291 {
292 	struct platform_device *pdev = to_platform_device(dev);
293 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
294 
295 	if (device_may_wakeup(&pdev->dev))
296 		matrix_keypad_disable_wakeup(keypad);
297 
298 	matrix_keypad_start(keypad->input_dev);
299 
300 	return 0;
301 }
302 #endif
303 
304 static SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
305 			 matrix_keypad_suspend, matrix_keypad_resume);
306 
307 static int matrix_keypad_init_gpio(struct platform_device *pdev,
308 				   struct matrix_keypad *keypad)
309 {
310 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
311 	int i, err;
312 
313 	/* initialized strobe lines as outputs, activated */
314 	for (i = 0; i < pdata->num_col_gpios; i++) {
315 		err = gpio_request(pdata->col_gpios[i], "matrix_kbd_col");
316 		if (err) {
317 			dev_err(&pdev->dev,
318 				"failed to request GPIO%d for COL%d\n",
319 				pdata->col_gpios[i], i);
320 			goto err_free_cols;
321 		}
322 
323 		gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
324 	}
325 
326 	for (i = 0; i < pdata->num_row_gpios; i++) {
327 		err = gpio_request(pdata->row_gpios[i], "matrix_kbd_row");
328 		if (err) {
329 			dev_err(&pdev->dev,
330 				"failed to request GPIO%d for ROW%d\n",
331 				pdata->row_gpios[i], i);
332 			goto err_free_rows;
333 		}
334 
335 		gpio_direction_input(pdata->row_gpios[i]);
336 	}
337 
338 	if (pdata->clustered_irq > 0) {
339 		err = request_any_context_irq(pdata->clustered_irq,
340 				matrix_keypad_interrupt,
341 				pdata->clustered_irq_flags,
342 				"matrix-keypad", keypad);
343 		if (err < 0) {
344 			dev_err(&pdev->dev,
345 				"Unable to acquire clustered interrupt\n");
346 			goto err_free_rows;
347 		}
348 	} else {
349 		for (i = 0; i < pdata->num_row_gpios; i++) {
350 			err = request_any_context_irq(
351 					gpio_to_irq(pdata->row_gpios[i]),
352 					matrix_keypad_interrupt,
353 					IRQF_TRIGGER_RISING |
354 					IRQF_TRIGGER_FALLING,
355 					"matrix-keypad", keypad);
356 			if (err < 0) {
357 				dev_err(&pdev->dev,
358 					"Unable to acquire interrupt for GPIO line %i\n",
359 					pdata->row_gpios[i]);
360 				goto err_free_irqs;
361 			}
362 		}
363 	}
364 
365 	/* initialized as disabled - enabled by input->open */
366 	disable_row_irqs(keypad);
367 	return 0;
368 
369 err_free_irqs:
370 	while (--i >= 0)
371 		free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
372 	i = pdata->num_row_gpios;
373 err_free_rows:
374 	while (--i >= 0)
375 		gpio_free(pdata->row_gpios[i]);
376 	i = pdata->num_col_gpios;
377 err_free_cols:
378 	while (--i >= 0)
379 		gpio_free(pdata->col_gpios[i]);
380 
381 	return err;
382 }
383 
384 static void matrix_keypad_free_gpio(struct matrix_keypad *keypad)
385 {
386 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
387 	int i;
388 
389 	if (pdata->clustered_irq > 0) {
390 		free_irq(pdata->clustered_irq, keypad);
391 	} else {
392 		for (i = 0; i < pdata->num_row_gpios; i++)
393 			free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
394 	}
395 
396 	for (i = 0; i < pdata->num_row_gpios; i++)
397 		gpio_free(pdata->row_gpios[i]);
398 
399 	for (i = 0; i < pdata->num_col_gpios; i++)
400 		gpio_free(pdata->col_gpios[i]);
401 }
402 
403 #ifdef CONFIG_OF
404 static struct matrix_keypad_platform_data *
405 matrix_keypad_parse_dt(struct device *dev)
406 {
407 	struct matrix_keypad_platform_data *pdata;
408 	struct device_node *np = dev->of_node;
409 	unsigned int *gpios;
410 	int i, nrow, ncol;
411 
412 	if (!np) {
413 		dev_err(dev, "device lacks DT data\n");
414 		return ERR_PTR(-ENODEV);
415 	}
416 
417 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
418 	if (!pdata) {
419 		dev_err(dev, "could not allocate memory for platform data\n");
420 		return ERR_PTR(-ENOMEM);
421 	}
422 
423 	pdata->num_row_gpios = nrow = of_gpio_named_count(np, "row-gpios");
424 	pdata->num_col_gpios = ncol = of_gpio_named_count(np, "col-gpios");
425 	if (nrow <= 0 || ncol <= 0) {
426 		dev_err(dev, "number of keypad rows/columns not specified\n");
427 		return ERR_PTR(-EINVAL);
428 	}
429 
430 	if (of_get_property(np, "linux,no-autorepeat", NULL))
431 		pdata->no_autorepeat = true;
432 
433 	pdata->wakeup = of_property_read_bool(np, "wakeup-source") ||
434 			of_property_read_bool(np, "linux,wakeup"); /* legacy */
435 
436 	if (of_get_property(np, "gpio-activelow", NULL))
437 		pdata->active_low = true;
438 
439 	pdata->drive_inactive_cols =
440 		of_property_read_bool(np, "drive-inactive-cols");
441 
442 	of_property_read_u32(np, "debounce-delay-ms", &pdata->debounce_ms);
443 	of_property_read_u32(np, "col-scan-delay-us",
444 						&pdata->col_scan_delay_us);
445 
446 	gpios = devm_kcalloc(dev,
447 			     pdata->num_row_gpios + pdata->num_col_gpios,
448 			     sizeof(unsigned int),
449 			     GFP_KERNEL);
450 	if (!gpios) {
451 		dev_err(dev, "could not allocate memory for gpios\n");
452 		return ERR_PTR(-ENOMEM);
453 	}
454 
455 	for (i = 0; i < pdata->num_row_gpios; i++)
456 		gpios[i] = of_get_named_gpio(np, "row-gpios", i);
457 
458 	for (i = 0; i < pdata->num_col_gpios; i++)
459 		gpios[pdata->num_row_gpios + i] =
460 			of_get_named_gpio(np, "col-gpios", i);
461 
462 	pdata->row_gpios = gpios;
463 	pdata->col_gpios = &gpios[pdata->num_row_gpios];
464 
465 	return pdata;
466 }
467 #else
468 static inline struct matrix_keypad_platform_data *
469 matrix_keypad_parse_dt(struct device *dev)
470 {
471 	dev_err(dev, "no platform data defined\n");
472 
473 	return ERR_PTR(-EINVAL);
474 }
475 #endif
476 
477 static int matrix_keypad_probe(struct platform_device *pdev)
478 {
479 	const struct matrix_keypad_platform_data *pdata;
480 	struct matrix_keypad *keypad;
481 	struct input_dev *input_dev;
482 	int err;
483 
484 	pdata = dev_get_platdata(&pdev->dev);
485 	if (!pdata) {
486 		pdata = matrix_keypad_parse_dt(&pdev->dev);
487 		if (IS_ERR(pdata)) {
488 			dev_err(&pdev->dev, "no platform data defined\n");
489 			return PTR_ERR(pdata);
490 		}
491 	} else if (!pdata->keymap_data) {
492 		dev_err(&pdev->dev, "no keymap data defined\n");
493 		return -EINVAL;
494 	}
495 
496 	keypad = kzalloc(sizeof(struct matrix_keypad), GFP_KERNEL);
497 	input_dev = input_allocate_device();
498 	if (!keypad || !input_dev) {
499 		err = -ENOMEM;
500 		goto err_free_mem;
501 	}
502 
503 	keypad->input_dev = input_dev;
504 	keypad->pdata = pdata;
505 	keypad->row_shift = get_count_order(pdata->num_col_gpios);
506 	keypad->stopped = true;
507 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
508 	spin_lock_init(&keypad->lock);
509 
510 	input_dev->name		= pdev->name;
511 	input_dev->id.bustype	= BUS_HOST;
512 	input_dev->dev.parent	= &pdev->dev;
513 	input_dev->open		= matrix_keypad_start;
514 	input_dev->close	= matrix_keypad_stop;
515 
516 	err = matrix_keypad_build_keymap(pdata->keymap_data, NULL,
517 					 pdata->num_row_gpios,
518 					 pdata->num_col_gpios,
519 					 NULL, input_dev);
520 	if (err) {
521 		dev_err(&pdev->dev, "failed to build keymap\n");
522 		goto err_free_mem;
523 	}
524 
525 	if (!pdata->no_autorepeat)
526 		__set_bit(EV_REP, input_dev->evbit);
527 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
528 	input_set_drvdata(input_dev, keypad);
529 
530 	err = matrix_keypad_init_gpio(pdev, keypad);
531 	if (err)
532 		goto err_free_mem;
533 
534 	err = input_register_device(keypad->input_dev);
535 	if (err)
536 		goto err_free_gpio;
537 
538 	device_init_wakeup(&pdev->dev, pdata->wakeup);
539 	platform_set_drvdata(pdev, keypad);
540 
541 	return 0;
542 
543 err_free_gpio:
544 	matrix_keypad_free_gpio(keypad);
545 err_free_mem:
546 	input_free_device(input_dev);
547 	kfree(keypad);
548 	return err;
549 }
550 
551 static int matrix_keypad_remove(struct platform_device *pdev)
552 {
553 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
554 
555 	matrix_keypad_free_gpio(keypad);
556 	input_unregister_device(keypad->input_dev);
557 	kfree(keypad);
558 
559 	return 0;
560 }
561 
562 #ifdef CONFIG_OF
563 static const struct of_device_id matrix_keypad_dt_match[] = {
564 	{ .compatible = "gpio-matrix-keypad" },
565 	{ }
566 };
567 MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
568 #endif
569 
570 static struct platform_driver matrix_keypad_driver = {
571 	.probe		= matrix_keypad_probe,
572 	.remove		= matrix_keypad_remove,
573 	.driver		= {
574 		.name	= "matrix-keypad",
575 		.pm	= &matrix_keypad_pm_ops,
576 		.of_match_table = of_match_ptr(matrix_keypad_dt_match),
577 	},
578 };
579 module_platform_driver(matrix_keypad_driver);
580 
581 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
582 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
583 MODULE_LICENSE("GPL v2");
584 MODULE_ALIAS("platform:matrix-keypad");
585