xref: /linux/drivers/input/keyboard/matrix_keypad.c (revision 566ab427f827b0256d3e8ce0235d088e6a9c28bd) 
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/gpio/consumer.h>
21 #include <linux/input/matrix_keypad.h>
22 #include <linux/slab.h>
23 #include <linux/of.h>
24 
25 struct matrix_keypad {
26 	struct input_dev *input_dev;
27 	unsigned int row_shift;
28 
29 	unsigned int col_scan_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 		udelay(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 
83 static bool row_asserted(struct matrix_keypad *keypad, int row)
84 {
85 	return gpiod_get_value_cansleep(keypad->row_gpios[row]);
86 }
87 
88 static void enable_row_irqs(struct matrix_keypad *keypad)
89 {
90 	int i;
91 
92 	for (i = 0; i < keypad->num_row_gpios; i++)
93 		enable_irq(keypad->row_irqs[i]);
94 }
95 
96 static void disable_row_irqs(struct matrix_keypad *keypad)
97 {
98 	int i;
99 
100 	for (i = 0; i < keypad->num_row_gpios; i++)
101 		disable_irq_nosync(keypad->row_irqs[i]);
102 }
103 
104 /*
105  * This gets the keys from keyboard and reports it to input subsystem
106  */
107 static void matrix_keypad_scan(struct work_struct *work)
108 {
109 	struct matrix_keypad *keypad =
110 		container_of(work, struct matrix_keypad, work.work);
111 	struct input_dev *input_dev = keypad->input_dev;
112 	const unsigned short *keycodes = input_dev->keycode;
113 	uint32_t new_state[MATRIX_MAX_COLS];
114 	int row, col, code;
115 
116 	/* de-activate all columns for scanning */
117 	activate_all_cols(keypad, false);
118 
119 	memset(new_state, 0, sizeof(new_state));
120 
121 	for (row = 0; row < keypad->num_row_gpios; row++)
122 		gpiod_direction_input(keypad->row_gpios[row]);
123 
124 	/* assert each column and read the row status out */
125 	for (col = 0; col < keypad->num_col_gpios; col++) {
126 
127 		activate_col(keypad, col, true);
128 
129 		for (row = 0; row < keypad->num_row_gpios; row++)
130 			new_state[col] |=
131 				row_asserted(keypad, row) ? BIT(row) : 0;
132 
133 		activate_col(keypad, col, false);
134 	}
135 
136 	for (col = 0; col < keypad->num_col_gpios; col++) {
137 		uint32_t bits_changed;
138 
139 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
140 		if (bits_changed == 0)
141 			continue;
142 
143 		for (row = 0; row < keypad->num_row_gpios; row++) {
144 			if (!(bits_changed & BIT(row)))
145 				continue;
146 
147 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
148 			input_event(input_dev, EV_MSC, MSC_SCAN, code);
149 			input_report_key(input_dev,
150 					 keycodes[code],
151 					 new_state[col] & (1 << row));
152 		}
153 	}
154 	input_sync(input_dev);
155 
156 	memcpy(keypad->last_key_state, new_state, sizeof(new_state));
157 
158 	activate_all_cols(keypad, true);
159 
160 	/* Enable IRQs again */
161 	spin_lock_irq(&keypad->lock);
162 	keypad->scan_pending = false;
163 	enable_row_irqs(keypad);
164 	spin_unlock_irq(&keypad->lock);
165 }
166 
167 static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
168 {
169 	struct matrix_keypad *keypad = id;
170 	unsigned long flags;
171 
172 	spin_lock_irqsave(&keypad->lock, flags);
173 
174 	/*
175 	 * See if another IRQ beaten us to it and scheduled the
176 	 * scan already. In that case we should not try to
177 	 * disable IRQs again.
178 	 */
179 	if (unlikely(keypad->scan_pending || keypad->stopped))
180 		goto out;
181 
182 	disable_row_irqs(keypad);
183 	keypad->scan_pending = true;
184 	schedule_delayed_work(&keypad->work,
185 			      msecs_to_jiffies(keypad->debounce_ms));
186 
187 out:
188 	spin_unlock_irqrestore(&keypad->lock, flags);
189 	return IRQ_HANDLED;
190 }
191 
192 static int matrix_keypad_start(struct input_dev *dev)
193 {
194 	struct matrix_keypad *keypad = input_get_drvdata(dev);
195 
196 	keypad->stopped = false;
197 	mb();
198 
199 	/*
200 	 * Schedule an immediate key scan to capture current key state;
201 	 * columns will be activated and IRQs be enabled after the scan.
202 	 */
203 	schedule_delayed_work(&keypad->work, 0);
204 
205 	return 0;
206 }
207 
208 static void matrix_keypad_stop(struct input_dev *dev)
209 {
210 	struct matrix_keypad *keypad = input_get_drvdata(dev);
211 
212 	spin_lock_irq(&keypad->lock);
213 	keypad->stopped = true;
214 	spin_unlock_irq(&keypad->lock);
215 
216 	flush_delayed_work(&keypad->work);
217 	/*
218 	 * matrix_keypad_scan() will leave IRQs enabled;
219 	 * we should disable them now.
220 	 */
221 	disable_row_irqs(keypad);
222 }
223 
224 static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
225 {
226 	int i;
227 
228 	for_each_clear_bit(i, keypad->wakeup_enabled_irqs,
229 			   keypad->num_row_gpios)
230 		if (enable_irq_wake(keypad->row_irqs[i]) == 0)
231 			__set_bit(i, keypad->wakeup_enabled_irqs);
232 }
233 
234 static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
235 {
236 	int i;
237 
238 	for_each_set_bit(i, keypad->wakeup_enabled_irqs,
239 			 keypad->num_row_gpios) {
240 		disable_irq_wake(keypad->row_irqs[i]);
241 		__clear_bit(i, keypad->wakeup_enabled_irqs);
242 	}
243 }
244 
245 static int matrix_keypad_suspend(struct device *dev)
246 {
247 	struct platform_device *pdev = to_platform_device(dev);
248 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
249 
250 	matrix_keypad_stop(keypad->input_dev);
251 
252 	if (device_may_wakeup(&pdev->dev))
253 		matrix_keypad_enable_wakeup(keypad);
254 
255 	return 0;
256 }
257 
258 static int matrix_keypad_resume(struct device *dev)
259 {
260 	struct platform_device *pdev = to_platform_device(dev);
261 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
262 
263 	if (device_may_wakeup(&pdev->dev))
264 		matrix_keypad_disable_wakeup(keypad);
265 
266 	matrix_keypad_start(keypad->input_dev);
267 
268 	return 0;
269 }
270 
271 static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
272 				matrix_keypad_suspend, matrix_keypad_resume);
273 
274 static int matrix_keypad_init_gpio(struct platform_device *pdev,
275 				   struct matrix_keypad *keypad)
276 {
277 	bool active_low;
278 	int nrow, ncol;
279 	int err;
280 	int i;
281 
282 	nrow = gpiod_count(&pdev->dev, "row");
283 	ncol = gpiod_count(&pdev->dev, "col");
284 	if (nrow < 0 || ncol < 0) {
285 		dev_err(&pdev->dev, "missing row or column GPIOs\n");
286 		return -EINVAL;
287 	}
288 
289 	keypad->num_row_gpios = nrow;
290 	keypad->num_col_gpios = ncol;
291 
292 	active_low = device_property_read_bool(&pdev->dev, "gpio-activelow");
293 
294 	/* initialize strobe lines as outputs, activated */
295 	for (i = 0; i < keypad->num_col_gpios; i++) {
296 		keypad->col_gpios[i] = devm_gpiod_get_index(&pdev->dev, "col",
297 							    i, GPIOD_ASIS);
298 		err = PTR_ERR_OR_ZERO(keypad->col_gpios[i]);
299 		if (err) {
300 			dev_err(&pdev->dev,
301 				"failed to request GPIO for COL%d: %d\n",
302 				i, err);
303 			return err;
304 		}
305 
306 		gpiod_set_consumer_name(keypad->col_gpios[i], "matrix_kbd_col");
307 
308 		if (active_low ^ gpiod_is_active_low(keypad->col_gpios[i]))
309 			gpiod_toggle_active_low(keypad->col_gpios[i]);
310 
311 		gpiod_direction_output(keypad->col_gpios[i], 1);
312 	}
313 
314 	for (i = 0; i < keypad->num_row_gpios; i++) {
315 		keypad->row_gpios[i] = devm_gpiod_get_index(&pdev->dev, "row",
316 							    i, GPIOD_IN);
317 		err = PTR_ERR_OR_ZERO(keypad->row_gpios[i]);
318 		if (err) {
319 			dev_err(&pdev->dev,
320 				"failed to request GPIO for ROW%d: %d\n",
321 				i, err);
322 			return err;
323 		}
324 
325 		gpiod_set_consumer_name(keypad->row_gpios[i], "matrix_kbd_row");
326 
327 		if (active_low ^ gpiod_is_active_low(keypad->row_gpios[i]))
328 			gpiod_toggle_active_low(keypad->row_gpios[i]);
329 	}
330 
331 	return 0;
332 }
333 
334 static int matrix_keypad_setup_interrupts(struct platform_device *pdev,
335 					  struct matrix_keypad *keypad)
336 {
337 	int err;
338 	int irq;
339 	int i;
340 
341 	for (i = 0; i < keypad->num_row_gpios; i++) {
342 		irq = gpiod_to_irq(keypad->row_gpios[i]);
343 		if (irq < 0) {
344 			err = irq;
345 			dev_err(&pdev->dev,
346 				"Unable to convert GPIO line %i to irq: %d\n",
347 				i, err);
348 			return err;
349 		}
350 
351 		err = devm_request_any_context_irq(&pdev->dev, irq,
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 row %i: %d\n",
359 				i, err);
360 			return err;
361 		}
362 
363 		keypad->row_irqs[i] = irq;
364 	}
365 
366 	/* initialized as disabled - enabled by input->open */
367 	disable_row_irqs(keypad);
368 
369 	return 0;
370 }
371 
372 static int matrix_keypad_probe(struct platform_device *pdev)
373 {
374 	struct matrix_keypad *keypad;
375 	struct input_dev *input_dev;
376 	bool wakeup;
377 	int err;
378 
379 	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
380 	if (!keypad)
381 		return -ENOMEM;
382 
383 	input_dev = devm_input_allocate_device(&pdev->dev);
384 	if (!input_dev)
385 		return -ENOMEM;
386 
387 	keypad->input_dev = input_dev;
388 	keypad->stopped = true;
389 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
390 	spin_lock_init(&keypad->lock);
391 
392 	keypad->drive_inactive_cols =
393 		device_property_read_bool(&pdev->dev, "drive-inactive-cols");
394 	device_property_read_u32(&pdev->dev, "debounce-delay-ms",
395 				 &keypad->debounce_ms);
396 	device_property_read_u32(&pdev->dev, "col-scan-delay-us",
397 				 &keypad->col_scan_delay_us);
398 
399 	err = matrix_keypad_init_gpio(pdev, keypad);
400 	if (err)
401 		return err;
402 
403 	keypad->row_shift = get_count_order(keypad->num_col_gpios);
404 
405 	err = matrix_keypad_setup_interrupts(pdev, keypad);
406 	if (err)
407 		return err;
408 
409 	input_dev->name		= pdev->name;
410 	input_dev->id.bustype	= BUS_HOST;
411 	input_dev->open		= matrix_keypad_start;
412 	input_dev->close	= matrix_keypad_stop;
413 
414 	err = matrix_keypad_build_keymap(NULL, NULL,
415 					 keypad->num_row_gpios,
416 					 keypad->num_col_gpios,
417 					 NULL, input_dev);
418 	if (err) {
419 		dev_err(&pdev->dev, "failed to build keymap\n");
420 		return -ENOMEM;
421 	}
422 
423 	if (!device_property_read_bool(&pdev->dev, "linux,no-autorepeat"))
424 		__set_bit(EV_REP, input_dev->evbit);
425 
426 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
427 	input_set_drvdata(input_dev, keypad);
428 
429 	err = input_register_device(keypad->input_dev);
430 	if (err)
431 		return err;
432 
433 	wakeup = device_property_read_bool(&pdev->dev, "wakeup-source") ||
434 		 /* legacy */
435 		 device_property_read_bool(&pdev->dev, "linux,wakeup");
436 	device_init_wakeup(&pdev->dev, wakeup);
437 
438 	platform_set_drvdata(pdev, keypad);
439 
440 	return 0;
441 }
442 
443 #ifdef CONFIG_OF
444 static const struct of_device_id matrix_keypad_dt_match[] = {
445 	{ .compatible = "gpio-matrix-keypad" },
446 	{ }
447 };
448 MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
449 #endif
450 
451 static struct platform_driver matrix_keypad_driver = {
452 	.probe		= matrix_keypad_probe,
453 	.driver		= {
454 		.name	= "matrix-keypad",
455 		.pm	= pm_sleep_ptr(&matrix_keypad_pm_ops),
456 		.of_match_table = of_match_ptr(matrix_keypad_dt_match),
457 	},
458 };
459 module_platform_driver(matrix_keypad_driver);
460 
461 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
462 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
463 MODULE_LICENSE("GPL v2");
464 MODULE_ALIAS("platform:matrix-keypad");
465