xref: /linux/drivers/input/keyboard/matrix_keypad.c (revision 9f13acb2406a3aed90c6738b3a2f1c0e43118cbd) 
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  */
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 
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 
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 
86 static bool row_asserted(struct matrix_keypad *keypad, int row)
87 {
88 	return gpiod_get_value_cansleep(keypad->row_gpios[row]);
89 }
90 
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 
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 
107 /*
108  * This gets the keys from keyboard and reports it to input subsystem
109  */
110 static void matrix_keypad_scan(struct work_struct *work)
111 {
112 	struct matrix_keypad *keypad =
113 		container_of(work, struct matrix_keypad, work.work);
114 	struct input_dev *input_dev = keypad->input_dev;
115 	const unsigned short *keycodes = input_dev->keycode;
116 	uint32_t new_state[MATRIX_MAX_COLS];
117 	int row, col, code;
118 
119 	/* de-activate all columns for scanning */
120 	activate_all_cols(keypad, false);
121 
122 	memset(new_state, 0, sizeof(new_state));
123 
124 	for (row = 0; row < keypad->num_row_gpios; row++)
125 		gpiod_direction_input(keypad->row_gpios[row]);
126 
127 	/* assert each column and read the row status out */
128 	for (col = 0; col < keypad->num_col_gpios; col++) {
129 
130 		activate_col(keypad, col, true);
131 
132 		for (row = 0; row < keypad->num_row_gpios; row++)
133 			new_state[col] |=
134 				row_asserted(keypad, row) ? BIT(row) : 0;
135 
136 		activate_col(keypad, col, false);
137 	}
138 
139 	for (col = 0; col < keypad->num_col_gpios; col++) {
140 		uint32_t bits_changed;
141 
142 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
143 		if (bits_changed == 0)
144 			continue;
145 
146 		for (row = 0; row < keypad->num_row_gpios; row++) {
147 			if (!(bits_changed & BIT(row)))
148 				continue;
149 
150 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
151 			input_event(input_dev, EV_MSC, MSC_SCAN, code);
152 			input_report_key(input_dev,
153 					 keycodes[code],
154 					 new_state[col] & (1 << row));
155 		}
156 	}
157 	input_sync(input_dev);
158 
159 	memcpy(keypad->last_key_state, new_state, sizeof(new_state));
160 
161 	activate_all_cols(keypad, true);
162 
163 	/* Enable IRQs again */
164 	scoped_guard(spinlock_irq, &keypad->lock) {
165 		keypad->scan_pending = false;
166 		enable_row_irqs(keypad);
167 	}
168 }
169 
170 static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
171 {
172 	struct matrix_keypad *keypad = id;
173 
174 	guard(spinlock_irqsave)(&keypad->lock);
175 
176 	/*
177 	 * See if another IRQ beaten us to it and scheduled the
178 	 * scan already. In that case we should not try to
179 	 * disable IRQs again.
180 	 */
181 	if (unlikely(keypad->scan_pending || keypad->stopped))
182 		goto out;
183 
184 	disable_row_irqs(keypad);
185 	keypad->scan_pending = true;
186 	schedule_delayed_work(&keypad->work,
187 			      msecs_to_jiffies(keypad->debounce_ms));
188 
189 out:
190 	return IRQ_HANDLED;
191 }
192 
193 static int matrix_keypad_start(struct input_dev *dev)
194 {
195 	struct matrix_keypad *keypad = input_get_drvdata(dev);
196 
197 	keypad->stopped = false;
198 	mb();
199 
200 	/*
201 	 * Schedule an immediate key scan to capture current key state;
202 	 * columns will be activated and IRQs be enabled after the scan.
203 	 */
204 	schedule_delayed_work(&keypad->work, 0);
205 
206 	return 0;
207 }
208 
209 static void matrix_keypad_stop(struct input_dev *dev)
210 {
211 	struct matrix_keypad *keypad = input_get_drvdata(dev);
212 
213 	scoped_guard(spinlock_irq, &keypad->lock) {
214 		keypad->stopped = true;
215 	}
216 
217 	flush_delayed_work(&keypad->work);
218 	/*
219 	 * matrix_keypad_scan() will leave IRQs enabled;
220 	 * we should disable them now.
221 	 */
222 	disable_row_irqs(keypad);
223 }
224 
225 static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
226 {
227 	int i;
228 
229 	for_each_clear_bit(i, keypad->wakeup_enabled_irqs,
230 			   keypad->num_row_gpios)
231 		if (enable_irq_wake(keypad->row_irqs[i]) == 0)
232 			__set_bit(i, keypad->wakeup_enabled_irqs);
233 }
234 
235 static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
236 {
237 	int i;
238 
239 	for_each_set_bit(i, keypad->wakeup_enabled_irqs,
240 			 keypad->num_row_gpios) {
241 		disable_irq_wake(keypad->row_irqs[i]);
242 		__clear_bit(i, keypad->wakeup_enabled_irqs);
243 	}
244 }
245 
246 static int matrix_keypad_suspend(struct device *dev)
247 {
248 	struct platform_device *pdev = to_platform_device(dev);
249 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
250 
251 	matrix_keypad_stop(keypad->input_dev);
252 
253 	if (device_may_wakeup(&pdev->dev))
254 		matrix_keypad_enable_wakeup(keypad);
255 
256 	return 0;
257 }
258 
259 static int matrix_keypad_resume(struct device *dev)
260 {
261 	struct platform_device *pdev = to_platform_device(dev);
262 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
263 
264 	if (device_may_wakeup(&pdev->dev))
265 		matrix_keypad_disable_wakeup(keypad);
266 
267 	matrix_keypad_start(keypad->input_dev);
268 
269 	return 0;
270 }
271 
272 static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
273 				matrix_keypad_suspend, matrix_keypad_resume);
274 
275 static int matrix_keypad_init_gpio(struct platform_device *pdev,
276 				   struct matrix_keypad *keypad)
277 {
278 	bool active_low;
279 	int nrow, ncol;
280 	int err;
281 	int i;
282 
283 	nrow = gpiod_count(&pdev->dev, "row");
284 	ncol = gpiod_count(&pdev->dev, "col");
285 	if (nrow < 0 || ncol < 0) {
286 		dev_err(&pdev->dev, "missing row or column GPIOs\n");
287 		return -EINVAL;
288 	}
289 
290 	keypad->num_row_gpios = nrow;
291 	keypad->num_col_gpios = ncol;
292 
293 	active_low = device_property_read_bool(&pdev->dev, "gpio-activelow");
294 
295 	/* initialize strobe lines as outputs, activated */
296 	for (i = 0; i < keypad->num_col_gpios; i++) {
297 		keypad->col_gpios[i] = devm_gpiod_get_index(&pdev->dev, "col",
298 							    i, GPIOD_ASIS);
299 		err = PTR_ERR_OR_ZERO(keypad->col_gpios[i]);
300 		if (err) {
301 			dev_err(&pdev->dev,
302 				"failed to request GPIO for COL%d: %d\n",
303 				i, err);
304 			return err;
305 		}
306 
307 		gpiod_set_consumer_name(keypad->col_gpios[i], "matrix_kbd_col");
308 
309 		if (active_low ^ gpiod_is_active_low(keypad->col_gpios[i]))
310 			gpiod_toggle_active_low(keypad->col_gpios[i]);
311 
312 		gpiod_direction_output(keypad->col_gpios[i], 1);
313 	}
314 
315 	for (i = 0; i < keypad->num_row_gpios; i++) {
316 		keypad->row_gpios[i] = devm_gpiod_get_index(&pdev->dev, "row",
317 							    i, GPIOD_IN);
318 		err = PTR_ERR_OR_ZERO(keypad->row_gpios[i]);
319 		if (err) {
320 			dev_err(&pdev->dev,
321 				"failed to request GPIO for ROW%d: %d\n",
322 				i, err);
323 			return err;
324 		}
325 
326 		gpiod_set_consumer_name(keypad->row_gpios[i], "matrix_kbd_row");
327 
328 		if (active_low ^ gpiod_is_active_low(keypad->row_gpios[i]))
329 			gpiod_toggle_active_low(keypad->row_gpios[i]);
330 	}
331 
332 	return 0;
333 }
334 
335 static int matrix_keypad_setup_interrupts(struct platform_device *pdev,
336 					  struct matrix_keypad *keypad)
337 {
338 	int err;
339 	int irq;
340 	int i;
341 
342 	for (i = 0; i < keypad->num_row_gpios; i++) {
343 		irq = gpiod_to_irq(keypad->row_gpios[i]);
344 		if (irq < 0) {
345 			err = irq;
346 			dev_err(&pdev->dev,
347 				"Unable to convert GPIO line %i to irq: %d\n",
348 				i, err);
349 			return err;
350 		}
351 
352 		err = devm_request_any_context_irq(&pdev->dev, irq,
353 						   matrix_keypad_interrupt,
354 						   IRQF_TRIGGER_RISING |
355 							IRQF_TRIGGER_FALLING,
356 						   "matrix-keypad", keypad);
357 		if (err < 0) {
358 			dev_err(&pdev->dev,
359 				"Unable to acquire interrupt for row %i: %d\n",
360 				i, err);
361 			return err;
362 		}
363 
364 		keypad->row_irqs[i] = irq;
365 	}
366 
367 	/* initialized as disabled - enabled by input->open */
368 	disable_row_irqs(keypad);
369 
370 	return 0;
371 }
372 
373 static int matrix_keypad_probe(struct platform_device *pdev)
374 {
375 	struct matrix_keypad *keypad;
376 	struct input_dev *input_dev;
377 	bool wakeup;
378 	int err;
379 
380 	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
381 	if (!keypad)
382 		return -ENOMEM;
383 
384 	input_dev = devm_input_allocate_device(&pdev->dev);
385 	if (!input_dev)
386 		return -ENOMEM;
387 
388 	keypad->input_dev = input_dev;
389 	keypad->stopped = true;
390 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
391 	spin_lock_init(&keypad->lock);
392 
393 	keypad->drive_inactive_cols =
394 		device_property_read_bool(&pdev->dev, "drive-inactive-cols");
395 	device_property_read_u32(&pdev->dev, "debounce-delay-ms",
396 				 &keypad->debounce_ms);
397 	device_property_read_u32(&pdev->dev, "col-scan-delay-us",
398 				 &keypad->col_scan_delay_us);
399 	device_property_read_u32(&pdev->dev, "all-cols-on-delay-us",
400 				 &keypad->all_cols_on_delay_us);
401 
402 	err = matrix_keypad_init_gpio(pdev, keypad);
403 	if (err)
404 		return err;
405 
406 	keypad->row_shift = get_count_order(keypad->num_col_gpios);
407 
408 	err = matrix_keypad_setup_interrupts(pdev, keypad);
409 	if (err)
410 		return err;
411 
412 	input_dev->name		= pdev->name;
413 	input_dev->id.bustype	= BUS_HOST;
414 	input_dev->open		= matrix_keypad_start;
415 	input_dev->close	= matrix_keypad_stop;
416 
417 	err = matrix_keypad_build_keymap(NULL, NULL,
418 					 keypad->num_row_gpios,
419 					 keypad->num_col_gpios,
420 					 NULL, input_dev);
421 	if (err) {
422 		dev_err(&pdev->dev, "failed to build keymap\n");
423 		return -ENOMEM;
424 	}
425 
426 	if (!device_property_read_bool(&pdev->dev, "linux,no-autorepeat"))
427 		__set_bit(EV_REP, input_dev->evbit);
428 
429 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
430 	input_set_drvdata(input_dev, keypad);
431 
432 	err = input_register_device(keypad->input_dev);
433 	if (err)
434 		return err;
435 
436 	wakeup = device_property_read_bool(&pdev->dev, "wakeup-source") ||
437 		 /* legacy */
438 		 device_property_read_bool(&pdev->dev, "linux,wakeup");
439 	device_init_wakeup(&pdev->dev, wakeup);
440 
441 	platform_set_drvdata(pdev, keypad);
442 
443 	return 0;
444 }
445 
446 #ifdef CONFIG_OF
447 static const struct of_device_id matrix_keypad_dt_match[] = {
448 	{ .compatible = "gpio-matrix-keypad" },
449 	{ }
450 };
451 MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
452 #endif
453 
454 static struct platform_driver matrix_keypad_driver = {
455 	.probe		= matrix_keypad_probe,
456 	.driver		= {
457 		.name	= "matrix-keypad",
458 		.pm	= pm_sleep_ptr(&matrix_keypad_pm_ops),
459 		.of_match_table = of_match_ptr(matrix_keypad_dt_match),
460 	},
461 };
462 module_platform_driver(matrix_keypad_driver);
463 
464 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
465 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
466 MODULE_LICENSE("GPL v2");
467 MODULE_ALIAS("platform:matrix-keypad");
468