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 
24 struct matrix_keypad {
25 	struct input_dev *input_dev;
26 	unsigned int row_shift;
27 
28 	unsigned int col_scan_delay_us;
29 	unsigned int all_cols_on_delay_us;
30 	/* key debounce interval in milli-second */
31 	unsigned int debounce_ms;
32 	bool drive_inactive_cols;
33 
34 	struct gpio_desc *row_gpios[MATRIX_MAX_ROWS];
35 	unsigned int num_row_gpios;
36 
37 	struct gpio_desc *col_gpios[MATRIX_MAX_ROWS];
38 	unsigned int num_col_gpios;
39 
40 	unsigned int row_irqs[MATRIX_MAX_ROWS];
41 	DECLARE_BITMAP(wakeup_enabled_irqs, MATRIX_MAX_ROWS);
42 
43 	uint32_t last_key_state[MATRIX_MAX_COLS];
44 	struct delayed_work work;
45 	spinlock_t lock;
46 	bool scan_pending;
47 	bool stopped;
48 };
49 
50 /*
51  * NOTE: If drive_inactive_cols is false, then the GPIO has to be put into
52  * HiZ when de-activated to cause minmal side effect when scanning other
53  * columns. In that case it is configured here to be input, otherwise it is
54  * driven with the inactive value.
55  */
__activate_col(struct matrix_keypad * keypad,int col,bool on)56 static void __activate_col(struct matrix_keypad *keypad, int col, bool on)
57 {
58 	if (on) {
59 		gpiod_direction_output(keypad->col_gpios[col], 1);
60 	} else {
61 		gpiod_set_value_cansleep(keypad->col_gpios[col], 0);
62 		if (!keypad->drive_inactive_cols)
63 			gpiod_direction_input(keypad->col_gpios[col]);
64 	}
65 }
66 
activate_col(struct matrix_keypad * keypad,int col,bool on)67 static void activate_col(struct matrix_keypad *keypad, int col, bool on)
68 {
69 	__activate_col(keypad, col, on);
70 
71 	if (on && keypad->col_scan_delay_us)
72 		fsleep(keypad->col_scan_delay_us);
73 }
74 
activate_all_cols(struct matrix_keypad * keypad,bool on)75 static void activate_all_cols(struct matrix_keypad *keypad, bool on)
76 {
77 	int col;
78 
79 	for (col = 0; col < keypad->num_col_gpios; col++)
80 		__activate_col(keypad, col, on);
81 
82 	if (on && keypad->all_cols_on_delay_us)
83 		fsleep(keypad->all_cols_on_delay_us);
84 }
85 
row_asserted(struct matrix_keypad * keypad,int row)86 static bool row_asserted(struct matrix_keypad *keypad, int row)
87 {
88 	return gpiod_get_value_cansleep(keypad->row_gpios[row]);
89 }
90 
enable_row_irqs(struct matrix_keypad * keypad)91 static void enable_row_irqs(struct matrix_keypad *keypad)
92 {
93 	int i;
94 
95 	for (i = 0; i < keypad->num_row_gpios; i++)
96 		enable_irq(keypad->row_irqs[i]);
97 }
98 
disable_row_irqs(struct matrix_keypad * keypad)99 static void disable_row_irqs(struct matrix_keypad *keypad)
100 {
101 	int i;
102 
103 	for (i = 0; i < keypad->num_row_gpios; i++)
104 		disable_irq_nosync(keypad->row_irqs[i]);
105 }
106 
read_row_state(struct matrix_keypad * keypad)107 static uint32_t read_row_state(struct matrix_keypad *keypad)
108 {
109 	int row;
110 	u32 row_state = 0;
111 
112 	for (row = 0; row < keypad->num_row_gpios; row++)
113 		row_state |= row_asserted(keypad, row) ? BIT(row) : 0;
114 	return row_state;
115 }
116 
117 /*
118  * This gets the keys from keyboard and reports it to input subsystem
119  */
matrix_keypad_scan(struct work_struct * work)120 static void matrix_keypad_scan(struct work_struct *work)
121 {
122 	struct matrix_keypad *keypad =
123 		container_of(work, struct matrix_keypad, work.work);
124 	struct input_dev *input_dev = keypad->input_dev;
125 	const unsigned short *keycodes = input_dev->keycode;
126 	uint32_t new_state[MATRIX_MAX_COLS];
127 	int row, col, code;
128 	u32 init_row_state, new_row_state;
129 
130 	/* read initial row state to detect changes between scan */
131 	init_row_state = read_row_state(keypad);
132 
133 	/* de-activate all columns for scanning */
134 	activate_all_cols(keypad, false);
135 
136 	memset(new_state, 0, sizeof(new_state));
137 
138 	for (row = 0; row < keypad->num_row_gpios; row++)
139 		gpiod_direction_input(keypad->row_gpios[row]);
140 
141 	/* assert each column and read the row status out */
142 	for (col = 0; col < keypad->num_col_gpios; col++) {
143 
144 		activate_col(keypad, col, true);
145 
146 		new_state[col] = read_row_state(keypad);
147 
148 		activate_col(keypad, col, false);
149 	}
150 
151 	for (col = 0; col < keypad->num_col_gpios; col++) {
152 		uint32_t bits_changed;
153 
154 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
155 		if (bits_changed == 0)
156 			continue;
157 
158 		for (row = 0; row < keypad->num_row_gpios; row++) {
159 			if (!(bits_changed & BIT(row)))
160 				continue;
161 
162 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
163 			input_event(input_dev, EV_MSC, MSC_SCAN, code);
164 			input_report_key(input_dev,
165 					 keycodes[code],
166 					 new_state[col] & (1 << row));
167 		}
168 	}
169 	input_sync(input_dev);
170 
171 	memcpy(keypad->last_key_state, new_state, sizeof(new_state));
172 
173 	activate_all_cols(keypad, true);
174 
175 	/* Enable IRQs again */
176 	scoped_guard(spinlock_irq, &keypad->lock) {
177 		keypad->scan_pending = false;
178 		enable_row_irqs(keypad);
179 	}
180 
181 	/* read new row state and detect if value has changed */
182 	new_row_state = read_row_state(keypad);
183 	if (init_row_state != new_row_state) {
184 		guard(spinlock_irq)(&keypad->lock);
185 		if (unlikely(keypad->scan_pending || keypad->stopped))
186 			return;
187 		disable_row_irqs(keypad);
188 		keypad->scan_pending = true;
189 		schedule_delayed_work(&keypad->work,
190 				      msecs_to_jiffies(keypad->debounce_ms));
191 	}
192 }
193 
matrix_keypad_interrupt(int irq,void * id)194 static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
195 {
196 	struct matrix_keypad *keypad = id;
197 
198 	guard(spinlock_irqsave)(&keypad->lock);
199 
200 	/*
201 	 * See if another IRQ beaten us to it and scheduled the
202 	 * scan already. In that case we should not try to
203 	 * disable IRQs again.
204 	 */
205 	if (unlikely(keypad->scan_pending || keypad->stopped))
206 		goto out;
207 
208 	disable_row_irqs(keypad);
209 	keypad->scan_pending = true;
210 	schedule_delayed_work(&keypad->work,
211 			      msecs_to_jiffies(keypad->debounce_ms));
212 
213 out:
214 	return IRQ_HANDLED;
215 }
216 
matrix_keypad_start(struct input_dev * dev)217 static int matrix_keypad_start(struct input_dev *dev)
218 {
219 	struct matrix_keypad *keypad = input_get_drvdata(dev);
220 
221 	keypad->stopped = false;
222 	mb();
223 
224 	/*
225 	 * Schedule an immediate key scan to capture current key state;
226 	 * columns will be activated and IRQs be enabled after the scan.
227 	 */
228 	schedule_delayed_work(&keypad->work, 0);
229 
230 	return 0;
231 }
232 
matrix_keypad_stop(struct input_dev * dev)233 static void matrix_keypad_stop(struct input_dev *dev)
234 {
235 	struct matrix_keypad *keypad = input_get_drvdata(dev);
236 
237 	scoped_guard(spinlock_irq, &keypad->lock) {
238 		keypad->stopped = true;
239 	}
240 
241 	flush_delayed_work(&keypad->work);
242 	/*
243 	 * matrix_keypad_scan() will leave IRQs enabled;
244 	 * we should disable them now.
245 	 */
246 	disable_row_irqs(keypad);
247 }
248 
matrix_keypad_enable_wakeup(struct matrix_keypad * keypad)249 static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
250 {
251 	int i;
252 
253 	for_each_clear_bit(i, keypad->wakeup_enabled_irqs,
254 			   keypad->num_row_gpios)
255 		if (enable_irq_wake(keypad->row_irqs[i]) == 0)
256 			__set_bit(i, keypad->wakeup_enabled_irqs);
257 }
258 
matrix_keypad_disable_wakeup(struct matrix_keypad * keypad)259 static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
260 {
261 	int i;
262 
263 	for_each_set_bit(i, keypad->wakeup_enabled_irqs,
264 			 keypad->num_row_gpios) {
265 		disable_irq_wake(keypad->row_irqs[i]);
266 		__clear_bit(i, keypad->wakeup_enabled_irqs);
267 	}
268 }
269 
matrix_keypad_suspend(struct device * dev)270 static int matrix_keypad_suspend(struct device *dev)
271 {
272 	struct platform_device *pdev = to_platform_device(dev);
273 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
274 
275 	matrix_keypad_stop(keypad->input_dev);
276 
277 	if (device_may_wakeup(&pdev->dev))
278 		matrix_keypad_enable_wakeup(keypad);
279 
280 	return 0;
281 }
282 
matrix_keypad_resume(struct device * dev)283 static int matrix_keypad_resume(struct device *dev)
284 {
285 	struct platform_device *pdev = to_platform_device(dev);
286 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
287 
288 	if (device_may_wakeup(&pdev->dev))
289 		matrix_keypad_disable_wakeup(keypad);
290 
291 	matrix_keypad_start(keypad->input_dev);
292 
293 	return 0;
294 }
295 
296 static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
297 				matrix_keypad_suspend, matrix_keypad_resume);
298 
matrix_keypad_init_gpio(struct platform_device * pdev,struct matrix_keypad * keypad)299 static int matrix_keypad_init_gpio(struct platform_device *pdev,
300 				   struct matrix_keypad *keypad)
301 {
302 	bool active_low;
303 	int nrow, ncol;
304 	int err;
305 	int i;
306 
307 	nrow = gpiod_count(&pdev->dev, "row");
308 	ncol = gpiod_count(&pdev->dev, "col");
309 	if (nrow < 0 || ncol < 0) {
310 		dev_err(&pdev->dev, "missing row or column GPIOs\n");
311 		return -EINVAL;
312 	}
313 
314 	keypad->num_row_gpios = nrow;
315 	keypad->num_col_gpios = ncol;
316 
317 	active_low = device_property_read_bool(&pdev->dev, "gpio-activelow");
318 
319 	/* initialize strobe lines as outputs, activated */
320 	for (i = 0; i < keypad->num_col_gpios; i++) {
321 		keypad->col_gpios[i] = devm_gpiod_get_index(&pdev->dev, "col",
322 							    i, GPIOD_ASIS);
323 		err = PTR_ERR_OR_ZERO(keypad->col_gpios[i]);
324 		if (err) {
325 			dev_err(&pdev->dev,
326 				"failed to request GPIO for COL%d: %d\n",
327 				i, err);
328 			return err;
329 		}
330 
331 		gpiod_set_consumer_name(keypad->col_gpios[i], "matrix_kbd_col");
332 
333 		if (active_low ^ gpiod_is_active_low(keypad->col_gpios[i]))
334 			gpiod_toggle_active_low(keypad->col_gpios[i]);
335 
336 		gpiod_direction_output(keypad->col_gpios[i], 1);
337 	}
338 
339 	for (i = 0; i < keypad->num_row_gpios; i++) {
340 		keypad->row_gpios[i] = devm_gpiod_get_index(&pdev->dev, "row",
341 							    i, GPIOD_IN);
342 		err = PTR_ERR_OR_ZERO(keypad->row_gpios[i]);
343 		if (err) {
344 			dev_err(&pdev->dev,
345 				"failed to request GPIO for ROW%d: %d\n",
346 				i, err);
347 			return err;
348 		}
349 
350 		gpiod_set_consumer_name(keypad->row_gpios[i], "matrix_kbd_row");
351 
352 		if (active_low ^ gpiod_is_active_low(keypad->row_gpios[i]))
353 			gpiod_toggle_active_low(keypad->row_gpios[i]);
354 	}
355 
356 	return 0;
357 }
358 
matrix_keypad_setup_interrupts(struct platform_device * pdev,struct matrix_keypad * keypad)359 static int matrix_keypad_setup_interrupts(struct platform_device *pdev,
360 					  struct matrix_keypad *keypad)
361 {
362 	int err;
363 	int irq;
364 	int i;
365 
366 	for (i = 0; i < keypad->num_row_gpios; i++) {
367 		irq = gpiod_to_irq(keypad->row_gpios[i]);
368 		if (irq < 0) {
369 			err = irq;
370 			dev_err(&pdev->dev,
371 				"Unable to convert GPIO line %i to irq: %d\n",
372 				i, err);
373 			return err;
374 		}
375 
376 		err = devm_request_any_context_irq(&pdev->dev, irq,
377 						   matrix_keypad_interrupt,
378 						   IRQF_TRIGGER_RISING |
379 							IRQF_TRIGGER_FALLING,
380 						   "matrix-keypad", keypad);
381 		if (err < 0) {
382 			dev_err(&pdev->dev,
383 				"Unable to acquire interrupt for row %i: %d\n",
384 				i, err);
385 			return err;
386 		}
387 
388 		keypad->row_irqs[i] = irq;
389 	}
390 
391 	/* initialized as disabled - enabled by input->open */
392 	disable_row_irqs(keypad);
393 
394 	return 0;
395 }
396 
matrix_keypad_probe(struct platform_device * pdev)397 static int matrix_keypad_probe(struct platform_device *pdev)
398 {
399 	struct matrix_keypad *keypad;
400 	struct input_dev *input_dev;
401 	bool wakeup;
402 	int err;
403 
404 	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
405 	if (!keypad)
406 		return -ENOMEM;
407 
408 	input_dev = devm_input_allocate_device(&pdev->dev);
409 	if (!input_dev)
410 		return -ENOMEM;
411 
412 	keypad->input_dev = input_dev;
413 	keypad->stopped = true;
414 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
415 	spin_lock_init(&keypad->lock);
416 
417 	keypad->drive_inactive_cols =
418 		device_property_read_bool(&pdev->dev, "drive-inactive-cols");
419 	device_property_read_u32(&pdev->dev, "debounce-delay-ms",
420 				 &keypad->debounce_ms);
421 	device_property_read_u32(&pdev->dev, "col-scan-delay-us",
422 				 &keypad->col_scan_delay_us);
423 	device_property_read_u32(&pdev->dev, "all-cols-on-delay-us",
424 				 &keypad->all_cols_on_delay_us);
425 
426 	err = matrix_keypad_init_gpio(pdev, keypad);
427 	if (err)
428 		return err;
429 
430 	keypad->row_shift = get_count_order(keypad->num_col_gpios);
431 
432 	err = matrix_keypad_setup_interrupts(pdev, keypad);
433 	if (err)
434 		return err;
435 
436 	input_dev->name		= pdev->name;
437 	input_dev->id.bustype	= BUS_HOST;
438 	input_dev->open		= matrix_keypad_start;
439 	input_dev->close	= matrix_keypad_stop;
440 
441 	err = matrix_keypad_build_keymap(NULL, NULL,
442 					 keypad->num_row_gpios,
443 					 keypad->num_col_gpios,
444 					 NULL, input_dev);
445 	if (err) {
446 		dev_err(&pdev->dev, "failed to build keymap\n");
447 		return -ENOMEM;
448 	}
449 
450 	if (!device_property_read_bool(&pdev->dev, "linux,no-autorepeat"))
451 		__set_bit(EV_REP, input_dev->evbit);
452 
453 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
454 	input_set_drvdata(input_dev, keypad);
455 
456 	err = input_register_device(keypad->input_dev);
457 	if (err)
458 		return err;
459 
460 	wakeup = device_property_read_bool(&pdev->dev, "wakeup-source") ||
461 		 /* legacy */
462 		 device_property_read_bool(&pdev->dev, "linux,wakeup");
463 	device_init_wakeup(&pdev->dev, wakeup);
464 
465 	platform_set_drvdata(pdev, keypad);
466 
467 	return 0;
468 }
469 
470 #ifdef CONFIG_OF
471 static const struct of_device_id matrix_keypad_dt_match[] = {
472 	{ .compatible = "gpio-matrix-keypad" },
473 	{ }
474 };
475 MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
476 #endif
477 
478 static struct platform_driver matrix_keypad_driver = {
479 	.probe		= matrix_keypad_probe,
480 	.driver		= {
481 		.name	= "matrix-keypad",
482 		.pm	= pm_sleep_ptr(&matrix_keypad_pm_ops),
483 		.of_match_table = of_match_ptr(matrix_keypad_dt_match),
484 	},
485 };
486 module_platform_driver(matrix_keypad_driver);
487 
488 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
489 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
490 MODULE_LICENSE("GPL v2");
491 MODULE_ALIAS("platform:matrix-keypad");
492