xref: /linux/drivers/input/keyboard/matrix_keypad.c (revision a33f32244d8550da8b4a26e277ce07d5c6d158b5) 
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/init.h>
18 #include <linux/input.h>
19 #include <linux/irq.h>
20 #include <linux/interrupt.h>
21 #include <linux/jiffies.h>
22 #include <linux/module.h>
23 #include <linux/gpio.h>
24 #include <linux/input/matrix_keypad.h>
25 #include <linux/slab.h>
26 
27 struct matrix_keypad {
28 	const struct matrix_keypad_platform_data *pdata;
29 	struct input_dev *input_dev;
30 	unsigned short *keycodes;
31 	unsigned int row_shift;
32 
33 	DECLARE_BITMAP(disabled_gpios, 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 };
41 
42 /*
43  * NOTE: normally the GPIO has to be put into HiZ when de-activated to cause
44  * minmal side effect when scanning other columns, here it is configured to
45  * be input, and it should work on most platforms.
46  */
47 static void __activate_col(const struct matrix_keypad_platform_data *pdata,
48 			   int col, bool on)
49 {
50 	bool level_on = !pdata->active_low;
51 
52 	if (on) {
53 		gpio_direction_output(pdata->col_gpios[col], level_on);
54 	} else {
55 		gpio_set_value_cansleep(pdata->col_gpios[col], !level_on);
56 		gpio_direction_input(pdata->col_gpios[col]);
57 	}
58 }
59 
60 static void activate_col(const struct matrix_keypad_platform_data *pdata,
61 			 int col, bool on)
62 {
63 	__activate_col(pdata, col, on);
64 
65 	if (on && pdata->col_scan_delay_us)
66 		udelay(pdata->col_scan_delay_us);
67 }
68 
69 static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
70 			      bool on)
71 {
72 	int col;
73 
74 	for (col = 0; col < pdata->num_col_gpios; col++)
75 		__activate_col(pdata, col, on);
76 }
77 
78 static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
79 			 int row)
80 {
81 	return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
82 			!pdata->active_low : pdata->active_low;
83 }
84 
85 static void enable_row_irqs(struct matrix_keypad *keypad)
86 {
87 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
88 	int i;
89 
90 	for (i = 0; i < pdata->num_row_gpios; i++)
91 		enable_irq(gpio_to_irq(pdata->row_gpios[i]));
92 }
93 
94 static void disable_row_irqs(struct matrix_keypad *keypad)
95 {
96 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
97 	int i;
98 
99 	for (i = 0; i < pdata->num_row_gpios; i++)
100 		disable_irq_nosync(gpio_to_irq(pdata->row_gpios[i]));
101 }
102 
103 /*
104  * This gets the keys from keyboard and reports it to input subsystem
105  */
106 static void matrix_keypad_scan(struct work_struct *work)
107 {
108 	struct matrix_keypad *keypad =
109 		container_of(work, struct matrix_keypad, work.work);
110 	struct input_dev *input_dev = keypad->input_dev;
111 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
112 	uint32_t new_state[MATRIX_MAX_COLS];
113 	int row, col, code;
114 
115 	/* de-activate all columns for scanning */
116 	activate_all_cols(pdata, false);
117 
118 	memset(new_state, 0, sizeof(new_state));
119 
120 	/* assert each column and read the row status out */
121 	for (col = 0; col < pdata->num_col_gpios; col++) {
122 
123 		activate_col(pdata, col, true);
124 
125 		for (row = 0; row < pdata->num_row_gpios; row++)
126 			new_state[col] |=
127 				row_asserted(pdata, row) ? (1 << row) : 0;
128 
129 		activate_col(pdata, col, false);
130 	}
131 
132 	for (col = 0; col < pdata->num_col_gpios; col++) {
133 		uint32_t bits_changed;
134 
135 		bits_changed = keypad->last_key_state[col] ^ new_state[col];
136 		if (bits_changed == 0)
137 			continue;
138 
139 		for (row = 0; row < pdata->num_row_gpios; row++) {
140 			if ((bits_changed & (1 << row)) == 0)
141 				continue;
142 
143 			code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
144 			input_event(input_dev, EV_MSC, MSC_SCAN, code);
145 			input_report_key(input_dev,
146 					 keypad->keycodes[code],
147 					 new_state[col] & (1 << row));
148 		}
149 	}
150 	input_sync(input_dev);
151 
152 	memcpy(keypad->last_key_state, new_state, sizeof(new_state));
153 
154 	activate_all_cols(pdata, true);
155 
156 	/* Enable IRQs again */
157 	spin_lock_irq(&keypad->lock);
158 	keypad->scan_pending = false;
159 	enable_row_irqs(keypad);
160 	spin_unlock_irq(&keypad->lock);
161 }
162 
163 static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
164 {
165 	struct matrix_keypad *keypad = id;
166 	unsigned long flags;
167 
168 	spin_lock_irqsave(&keypad->lock, flags);
169 
170 	/*
171 	 * See if another IRQ beaten us to it and scheduled the
172 	 * scan already. In that case we should not try to
173 	 * disable IRQs again.
174 	 */
175 	if (unlikely(keypad->scan_pending || keypad->stopped))
176 		goto out;
177 
178 	disable_row_irqs(keypad);
179 	keypad->scan_pending = true;
180 	schedule_delayed_work(&keypad->work,
181 		msecs_to_jiffies(keypad->pdata->debounce_ms));
182 
183 out:
184 	spin_unlock_irqrestore(&keypad->lock, flags);
185 	return IRQ_HANDLED;
186 }
187 
188 static int matrix_keypad_start(struct input_dev *dev)
189 {
190 	struct matrix_keypad *keypad = input_get_drvdata(dev);
191 
192 	keypad->stopped = false;
193 	mb();
194 
195 	/*
196 	 * Schedule an immediate key scan to capture current key state;
197 	 * columns will be activated and IRQs be enabled after the scan.
198 	 */
199 	schedule_delayed_work(&keypad->work, 0);
200 
201 	return 0;
202 }
203 
204 static void matrix_keypad_stop(struct input_dev *dev)
205 {
206 	struct matrix_keypad *keypad = input_get_drvdata(dev);
207 
208 	keypad->stopped = true;
209 	mb();
210 	flush_work(&keypad->work.work);
211 	/*
212 	 * matrix_keypad_scan() will leave IRQs enabled;
213 	 * we should disable them now.
214 	 */
215 	disable_row_irqs(keypad);
216 }
217 
218 #ifdef CONFIG_PM
219 static int matrix_keypad_suspend(struct device *dev)
220 {
221 	struct platform_device *pdev = to_platform_device(dev);
222 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
223 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
224 	int i;
225 
226 	matrix_keypad_stop(keypad->input_dev);
227 
228 	if (device_may_wakeup(&pdev->dev)) {
229 		for (i = 0; i < pdata->num_row_gpios; i++) {
230 			if (!test_bit(i, keypad->disabled_gpios)) {
231 				unsigned int gpio = pdata->row_gpios[i];
232 
233 				if (enable_irq_wake(gpio_to_irq(gpio)) == 0)
234 					__set_bit(i, keypad->disabled_gpios);
235 			}
236 		}
237 	}
238 
239 	return 0;
240 }
241 
242 static int matrix_keypad_resume(struct device *dev)
243 {
244 	struct platform_device *pdev = to_platform_device(dev);
245 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
246 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
247 	int i;
248 
249 	if (device_may_wakeup(&pdev->dev)) {
250 		for (i = 0; i < pdata->num_row_gpios; i++) {
251 			if (test_and_clear_bit(i, keypad->disabled_gpios)) {
252 				unsigned int gpio = pdata->row_gpios[i];
253 
254 				disable_irq_wake(gpio_to_irq(gpio));
255 			}
256 		}
257 	}
258 
259 	matrix_keypad_start(keypad->input_dev);
260 
261 	return 0;
262 }
263 
264 static const SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
265 				matrix_keypad_suspend, matrix_keypad_resume);
266 #endif
267 
268 static int __devinit init_matrix_gpio(struct platform_device *pdev,
269 					struct matrix_keypad *keypad)
270 {
271 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
272 	int i, err = -EINVAL;
273 
274 	/* initialized strobe lines as outputs, activated */
275 	for (i = 0; i < pdata->num_col_gpios; i++) {
276 		err = gpio_request(pdata->col_gpios[i], "matrix_kbd_col");
277 		if (err) {
278 			dev_err(&pdev->dev,
279 				"failed to request GPIO%d for COL%d\n",
280 				pdata->col_gpios[i], i);
281 			goto err_free_cols;
282 		}
283 
284 		gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
285 	}
286 
287 	for (i = 0; i < pdata->num_row_gpios; i++) {
288 		err = gpio_request(pdata->row_gpios[i], "matrix_kbd_row");
289 		if (err) {
290 			dev_err(&pdev->dev,
291 				"failed to request GPIO%d for ROW%d\n",
292 				pdata->row_gpios[i], i);
293 			goto err_free_rows;
294 		}
295 
296 		gpio_direction_input(pdata->row_gpios[i]);
297 	}
298 
299 	for (i = 0; i < pdata->num_row_gpios; i++) {
300 		err = request_irq(gpio_to_irq(pdata->row_gpios[i]),
301 				matrix_keypad_interrupt,
302 				IRQF_DISABLED |
303 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
304 				"matrix-keypad", keypad);
305 		if (err) {
306 			dev_err(&pdev->dev,
307 				"Unable to acquire interrupt for GPIO line %i\n",
308 				pdata->row_gpios[i]);
309 			goto err_free_irqs;
310 		}
311 	}
312 
313 	/* initialized as disabled - enabled by input->open */
314 	disable_row_irqs(keypad);
315 	return 0;
316 
317 err_free_irqs:
318 	while (--i >= 0)
319 		free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
320 	i = pdata->num_row_gpios;
321 err_free_rows:
322 	while (--i >= 0)
323 		gpio_free(pdata->row_gpios[i]);
324 	i = pdata->num_col_gpios;
325 err_free_cols:
326 	while (--i >= 0)
327 		gpio_free(pdata->col_gpios[i]);
328 
329 	return err;
330 }
331 
332 static int __devinit matrix_keypad_probe(struct platform_device *pdev)
333 {
334 	const struct matrix_keypad_platform_data *pdata;
335 	const struct matrix_keymap_data *keymap_data;
336 	struct matrix_keypad *keypad;
337 	struct input_dev *input_dev;
338 	unsigned short *keycodes;
339 	unsigned int row_shift;
340 	int err;
341 
342 	pdata = pdev->dev.platform_data;
343 	if (!pdata) {
344 		dev_err(&pdev->dev, "no platform data defined\n");
345 		return -EINVAL;
346 	}
347 
348 	keymap_data = pdata->keymap_data;
349 	if (!keymap_data) {
350 		dev_err(&pdev->dev, "no keymap data defined\n");
351 		return -EINVAL;
352 	}
353 
354 	row_shift = get_count_order(pdata->num_col_gpios);
355 
356 	keypad = kzalloc(sizeof(struct matrix_keypad), GFP_KERNEL);
357 	keycodes = kzalloc((pdata->num_row_gpios << row_shift) *
358 				sizeof(*keycodes),
359 			   GFP_KERNEL);
360 	input_dev = input_allocate_device();
361 	if (!keypad || !keycodes || !input_dev) {
362 		err = -ENOMEM;
363 		goto err_free_mem;
364 	}
365 
366 	keypad->input_dev = input_dev;
367 	keypad->pdata = pdata;
368 	keypad->keycodes = keycodes;
369 	keypad->row_shift = row_shift;
370 	keypad->stopped = true;
371 	INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
372 	spin_lock_init(&keypad->lock);
373 
374 	input_dev->name		= pdev->name;
375 	input_dev->id.bustype	= BUS_HOST;
376 	input_dev->dev.parent	= &pdev->dev;
377 	input_dev->evbit[0]	= BIT_MASK(EV_KEY);
378 	if (!pdata->no_autorepeat)
379 		input_dev->evbit[0] |= BIT_MASK(EV_REP);
380 	input_dev->open		= matrix_keypad_start;
381 	input_dev->close	= matrix_keypad_stop;
382 
383 	input_dev->keycode	= keycodes;
384 	input_dev->keycodesize	= sizeof(*keycodes);
385 	input_dev->keycodemax	= pdata->num_row_gpios << row_shift;
386 
387 	matrix_keypad_build_keymap(keymap_data, row_shift,
388 				   input_dev->keycode, input_dev->keybit);
389 
390 	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
391 	input_set_drvdata(input_dev, keypad);
392 
393 	err = init_matrix_gpio(pdev, keypad);
394 	if (err)
395 		goto err_free_mem;
396 
397 	err = input_register_device(keypad->input_dev);
398 	if (err)
399 		goto err_free_mem;
400 
401 	device_init_wakeup(&pdev->dev, pdata->wakeup);
402 	platform_set_drvdata(pdev, keypad);
403 
404 	return 0;
405 
406 err_free_mem:
407 	input_free_device(input_dev);
408 	kfree(keycodes);
409 	kfree(keypad);
410 	return err;
411 }
412 
413 static int __devexit matrix_keypad_remove(struct platform_device *pdev)
414 {
415 	struct matrix_keypad *keypad = platform_get_drvdata(pdev);
416 	const struct matrix_keypad_platform_data *pdata = keypad->pdata;
417 	int i;
418 
419 	device_init_wakeup(&pdev->dev, 0);
420 
421 	for (i = 0; i < pdata->num_row_gpios; i++) {
422 		free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
423 		gpio_free(pdata->row_gpios[i]);
424 	}
425 
426 	for (i = 0; i < pdata->num_col_gpios; i++)
427 		gpio_free(pdata->col_gpios[i]);
428 
429 	input_unregister_device(keypad->input_dev);
430 	platform_set_drvdata(pdev, NULL);
431 	kfree(keypad->keycodes);
432 	kfree(keypad);
433 
434 	return 0;
435 }
436 
437 static struct platform_driver matrix_keypad_driver = {
438 	.probe		= matrix_keypad_probe,
439 	.remove		= __devexit_p(matrix_keypad_remove),
440 	.driver		= {
441 		.name	= "matrix-keypad",
442 		.owner	= THIS_MODULE,
443 #ifdef CONFIG_PM
444 		.pm	= &matrix_keypad_pm_ops,
445 #endif
446 	},
447 };
448 
449 static int __init matrix_keypad_init(void)
450 {
451 	return platform_driver_register(&matrix_keypad_driver);
452 }
453 
454 static void __exit matrix_keypad_exit(void)
455 {
456 	platform_driver_unregister(&matrix_keypad_driver);
457 }
458 
459 module_init(matrix_keypad_init);
460 module_exit(matrix_keypad_exit);
461 
462 MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
463 MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
464 MODULE_LICENSE("GPL v2");
465 MODULE_ALIAS("platform:matrix-keypad");
466