xref: /linux/drivers/input/keyboard/matrix_keypad.c (revision 5832c4a77d6931cebf9ba737129ae8f14b66ee1d) 
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 #include <linux/of_gpio.h>
24 #include <linux/of_platform.h>
25 
26 struct matrix_keypad {
27 	const struct matrix_keypad_platform_data *pdata;
28 	struct input_dev *input_dev;
29 	unsigned int row_shift;
30 
31 	unsigned int row_irqs[MATRIX_MAX_ROWS];
32 	unsigned int num_row_irqs;
33 	DECLARE_BITMAP(wakeup_enabled_irqs, MATRIX_MAX_ROWS);
34 
35 	uint32_t last_key_state[MATRIX_MAX_COLS];
36 	struct delayed_work work;
37 	spinlock_t lock;
38 	bool scan_pending;
39 	bool stopped;
40 	bool gpio_all_disabled;
41 };
42 
43 /*
44  * NOTE: If drive_inactive_cols is false, then the GPIO has to be put into
45  * HiZ when de-activated to cause minmal side effect when scanning other
46  * columns. In that case it is configured here to be input, otherwise it is
47  * driven with the inactive value.
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 		if (!pdata->drive_inactive_cols)
59 			gpio_direction_input(pdata->col_gpios[col]);
60 	}
61 }
62 
63 static void activate_col(const struct matrix_keypad_platform_data *pdata,
64 			 int col, bool on)
65 {
66 	__activate_col(pdata, col, on);
67 
68 	if (on && pdata->col_scan_delay_us)
69 		udelay(pdata->col_scan_delay_us);
70 }
71 
72 static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
73 			      bool on)
74 {
75 	int col;
76 
77 	for (col = 0; col < pdata->num_col_gpios; col++)
78 		__activate_col(pdata, col, on);
79 }
80 
81 static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
82 			 int row)
83 {
84 	return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
85 			!pdata->active_low : pdata->active_low;
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_irqs; 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_irqs; 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 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
114 	uint32_t new_state[MATRIX_MAX_COLS];
115 	int row, col, code;
116 
117 	/* de-activate all columns for scanning */
118 	activate_all_cols(pdata, false);
119 
120 	memset(new_state, 0, sizeof(new_state));
121 
122 	for (row = 0; row < pdata->num_row_gpios; row++)
123 		gpio_direction_input(pdata->row_gpios[row]);
124 
125 	/* assert each column and read the row status out */
126 	for (col = 0; col < pdata->num_col_gpios; col++) {
127 
128 		activate_col(pdata, col, true);
129 
130 		for (row = 0; row < pdata->num_row_gpios; row++)
131 			new_state[col] |=
132 				row_asserted(pdata, row) ? (1 << row) : 0;
133 
134 		activate_col(pdata, col, false);
135 	}
136 
137 	for (col = 0; col < pdata->num_col_gpios; col++) {
138 		uint32_t bits_changed;
139 
140 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
141 		if (bits_changed == 0)
142 			continue;
143 
144 		for (row = 0; row < pdata->num_row_gpios; row++) {
145 			if ((bits_changed & (1 << row)) == 0)
146 				continue;
147 
148 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
149 			input_event(input_dev, EV_MSC, MSC_SCAN, code);
150 			input_report_key(input_dev,
151 					 keycodes[code],
152 					 new_state[col] & (1 << row));
153 		}
154 	}
155 	input_sync(input_dev);
156 
157 	memcpy(keypad->last_key_state, new_state, sizeof(new_state));
158 
159 	activate_all_cols(pdata, true);
160 
161 	/* Enable IRQs again */
162 	spin_lock_irq(&keypad->lock);
163 	keypad->scan_pending = false;
164 	enable_row_irqs(keypad);
165 	spin_unlock_irq(&keypad->lock);
166 }
167 
168 static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
169 {
170 	struct matrix_keypad *keypad = id;
171 	unsigned long flags;
172 
173 	spin_lock_irqsave(&keypad->lock, flags);
174 
175 	/*
176 	 * See if another IRQ beaten us to it and scheduled the
177 	 * scan already. In that case we should not try to
178 	 * disable IRQs again.
179 	 */
180 	if (unlikely(keypad->scan_pending || keypad->stopped))
181 		goto out;
182 
183 	disable_row_irqs(keypad);
184 	keypad->scan_pending = true;
185 	schedule_delayed_work(&keypad->work,
186 		msecs_to_jiffies(keypad->pdata->debounce_ms));
187 
188 out:
189 	spin_unlock_irqrestore(&keypad->lock, flags);
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 	spin_lock_irq(&keypad->lock);
214 	keypad->stopped = true;
215 	spin_unlock_irq(&keypad->lock);
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, keypad->num_row_irqs)
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, keypad->num_row_irqs) {
239 		disable_irq_wake(keypad->row_irqs[i]);
240 		__clear_bit(i, keypad->wakeup_enabled_irqs);
241 	}
242 }
243 
244 static int matrix_keypad_suspend(struct device *dev)
245 {
246 	struct platform_device *pdev = to_platform_device(dev);
247 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
248 
249 	matrix_keypad_stop(keypad->input_dev);
250 
251 	if (device_may_wakeup(&pdev->dev))
252 		matrix_keypad_enable_wakeup(keypad);
253 
254 	return 0;
255 }
256 
257 static int matrix_keypad_resume(struct device *dev)
258 {
259 	struct platform_device *pdev = to_platform_device(dev);
260 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
261 
262 	if (device_may_wakeup(&pdev->dev))
263 		matrix_keypad_disable_wakeup(keypad);
264 
265 	matrix_keypad_start(keypad->input_dev);
266 
267 	return 0;
268 }
269 
270 static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
271 				matrix_keypad_suspend, matrix_keypad_resume);
272 
273 static int matrix_keypad_init_gpio(struct platform_device *pdev,
274 				   struct matrix_keypad *keypad)
275 {
276 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
277 	int i, irq, err;
278 
279 	/* initialized strobe lines as outputs, activated */
280 	for (i = 0; i < pdata->num_col_gpios; i++) {
281 		err = devm_gpio_request(&pdev->dev,
282 					pdata->col_gpios[i], "matrix_kbd_col");
283 		if (err) {
284 			dev_err(&pdev->dev,
285 				"failed to request GPIO%d for COL%d\n",
286 				pdata->col_gpios[i], i);
287 			return err;
288 		}
289 
290 		gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
291 	}
292 
293 	for (i = 0; i < pdata->num_row_gpios; i++) {
294 		err = devm_gpio_request(&pdev->dev,
295 					pdata->row_gpios[i], "matrix_kbd_row");
296 		if (err) {
297 			dev_err(&pdev->dev,
298 				"failed to request GPIO%d for ROW%d\n",
299 				pdata->row_gpios[i], i);
300 			return err;
301 		}
302 
303 		gpio_direction_input(pdata->row_gpios[i]);
304 	}
305 
306 	if (pdata->clustered_irq > 0) {
307 		err = devm_request_any_context_irq(&pdev->dev,
308 				pdata->clustered_irq,
309 				matrix_keypad_interrupt,
310 				pdata->clustered_irq_flags,
311 				"matrix-keypad", keypad);
312 		if (err < 0) {
313 			dev_err(&pdev->dev,
314 				"Unable to acquire clustered interrupt\n");
315 			return err;
316 		}
317 
318 		keypad->row_irqs[0] = pdata->clustered_irq;
319 		keypad->num_row_irqs = 1;
320 	} else {
321 		for (i = 0; i < pdata->num_row_gpios; i++) {
322 			irq = gpio_to_irq(pdata->row_gpios[i]);
323 			if (irq < 0) {
324 				err = irq;
325 				dev_err(&pdev->dev,
326 					"Unable to convert GPIO line %i to irq: %d\n",
327 					pdata->row_gpios[i], err);
328 				return err;
329 			}
330 
331 			err = devm_request_any_context_irq(&pdev->dev,
332 					irq,
333 					matrix_keypad_interrupt,
334 					IRQF_TRIGGER_RISING |
335 						IRQF_TRIGGER_FALLING,
336 					"matrix-keypad", keypad);
337 			if (err < 0) {
338 				dev_err(&pdev->dev,
339 					"Unable to acquire interrupt for GPIO line %i\n",
340 					pdata->row_gpios[i]);
341 				return err;
342 			}
343 
344 			keypad->row_irqs[i] = irq;
345 		}
346 
347 		keypad->num_row_irqs = pdata->num_row_gpios;
348 	}
349 
350 	/* initialized as disabled - enabled by input->open */
351 	disable_row_irqs(keypad);
352 
353 	return 0;
354 }
355 
356 #ifdef CONFIG_OF
357 static struct matrix_keypad_platform_data *
358 matrix_keypad_parse_dt(struct device *dev)
359 {
360 	struct matrix_keypad_platform_data *pdata;
361 	struct device_node *np = dev->of_node;
362 	unsigned int *gpios;
363 	int ret, i, nrow, ncol;
364 
365 	if (!np) {
366 		dev_err(dev, "device lacks DT data\n");
367 		return ERR_PTR(-ENODEV);
368 	}
369 
370 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
371 	if (!pdata) {
372 		dev_err(dev, "could not allocate memory for platform data\n");
373 		return ERR_PTR(-ENOMEM);
374 	}
375 
376 	pdata->num_row_gpios = nrow = gpiod_count(dev, "row");
377 	pdata->num_col_gpios = ncol = gpiod_count(dev, "col");
378 	if (nrow < 0 || ncol < 0) {
379 		dev_err(dev, "number of keypad rows/columns not specified\n");
380 		return ERR_PTR(-EINVAL);
381 	}
382 
383 	pdata->no_autorepeat = of_property_read_bool(np, "linux,no-autorepeat");
384 
385 	pdata->wakeup = of_property_read_bool(np, "wakeup-source") ||
386 			of_property_read_bool(np, "linux,wakeup"); /* legacy */
387 
388 	pdata->active_low = of_property_read_bool(np, "gpio-activelow");
389 
390 	pdata->drive_inactive_cols =
391 		of_property_read_bool(np, "drive-inactive-cols");
392 
393 	of_property_read_u32(np, "debounce-delay-ms", &pdata->debounce_ms);
394 	of_property_read_u32(np, "col-scan-delay-us",
395 						&pdata->col_scan_delay_us);
396 
397 	gpios = devm_kcalloc(dev,
398 			     pdata->num_row_gpios + pdata->num_col_gpios,
399 			     sizeof(unsigned int),
400 			     GFP_KERNEL);
401 	if (!gpios) {
402 		dev_err(dev, "could not allocate memory for gpios\n");
403 		return ERR_PTR(-ENOMEM);
404 	}
405 
406 	for (i = 0; i < nrow; i++) {
407 		ret = of_get_named_gpio(np, "row-gpios", i);
408 		if (ret < 0)
409 			return ERR_PTR(ret);
410 		gpios[i] = ret;
411 	}
412 
413 	for (i = 0; i < ncol; i++) {
414 		ret = of_get_named_gpio(np, "col-gpios", i);
415 		if (ret < 0)
416 			return ERR_PTR(ret);
417 		gpios[nrow + i] = ret;
418 	}
419 
420 	pdata->row_gpios = gpios;
421 	pdata->col_gpios = &gpios[pdata->num_row_gpios];
422 
423 	return pdata;
424 }
425 #else
426 static inline struct matrix_keypad_platform_data *
427 matrix_keypad_parse_dt(struct device *dev)
428 {
429 	dev_err(dev, "no platform data defined\n");
430 
431 	return ERR_PTR(-EINVAL);
432 }
433 #endif
434 
435 static int matrix_keypad_probe(struct platform_device *pdev)
436 {
437 	const struct matrix_keypad_platform_data *pdata;
438 	struct matrix_keypad *keypad;
439 	struct input_dev *input_dev;
440 	int err;
441 
442 	pdata = dev_get_platdata(&pdev->dev);
443 	if (!pdata) {
444 		pdata = matrix_keypad_parse_dt(&pdev->dev);
445 		if (IS_ERR(pdata))
446 			return PTR_ERR(pdata);
447 	} else if (!pdata->keymap_data) {
448 		dev_err(&pdev->dev, "no keymap data defined\n");
449 		return -EINVAL;
450 	}
451 
452 	keypad = devm_kzalloc(&pdev->dev, sizeof(*keypad), GFP_KERNEL);
453 	if (!keypad)
454 		return -ENOMEM;
455 
456 	input_dev = devm_input_allocate_device(&pdev->dev);
457 	if (!input_dev)
458 		return -ENOMEM;
459 
460 	keypad->input_dev = input_dev;
461 	keypad->pdata = pdata;
462 	keypad->row_shift = get_count_order(pdata->num_col_gpios);
463 	keypad->stopped = true;
464 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
465 	spin_lock_init(&keypad->lock);
466 
467 	input_dev->name		= pdev->name;
468 	input_dev->id.bustype	= BUS_HOST;
469 	input_dev->open		= matrix_keypad_start;
470 	input_dev->close	= matrix_keypad_stop;
471 
472 	err = matrix_keypad_build_keymap(pdata->keymap_data, NULL,
473 					 pdata->num_row_gpios,
474 					 pdata->num_col_gpios,
475 					 NULL, input_dev);
476 	if (err) {
477 		dev_err(&pdev->dev, "failed to build keymap\n");
478 		return -ENOMEM;
479 	}
480 
481 	if (!pdata->no_autorepeat)
482 		__set_bit(EV_REP, input_dev->evbit);
483 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
484 	input_set_drvdata(input_dev, keypad);
485 
486 	err = matrix_keypad_init_gpio(pdev, keypad);
487 	if (err)
488 		return err;
489 
490 	err = input_register_device(keypad->input_dev);
491 	if (err)
492 		return err;
493 
494 	device_init_wakeup(&pdev->dev, pdata->wakeup);
495 	platform_set_drvdata(pdev, keypad);
496 
497 	return 0;
498 }
499 
500 #ifdef CONFIG_OF
501 static const struct of_device_id matrix_keypad_dt_match[] = {
502 	{ .compatible = "gpio-matrix-keypad" },
503 	{ }
504 };
505 MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
506 #endif
507 
508 static struct platform_driver matrix_keypad_driver = {
509 	.probe		= matrix_keypad_probe,
510 	.driver		= {
511 		.name	= "matrix-keypad",
512 		.pm	= pm_sleep_ptr(&matrix_keypad_pm_ops),
513 		.of_match_table = of_match_ptr(matrix_keypad_dt_match),
514 	},
515 };
516 module_platform_driver(matrix_keypad_driver);
517 
518 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
519 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
520 MODULE_LICENSE("GPL v2");
521 MODULE_ALIAS("platform:matrix-keypad");
522