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
24struct 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 */
56static void __activate_col(struct matrix_keypad *keypad, int col, bool on)
57{
58 if (on) {
59 gpiod_direction_output(desc: keypad->col_gpios[col], value: 1);
60 } else {
61 gpiod_set_value_cansleep(desc: keypad->col_gpios[col], value: 0);
62 if (!keypad->drive_inactive_cols)
63 gpiod_direction_input(desc: keypad->col_gpios[col]);
64 }
65}
66
67static 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(usecs: keypad->col_scan_delay_us);
73}
74
75static 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(usecs: keypad->all_cols_on_delay_us);
84}
85
86static bool row_asserted(struct matrix_keypad *keypad, int row)
87{
88 return gpiod_get_value_cansleep(desc: keypad->row_gpios[row]);
89}
90
91static 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(irq: keypad->row_irqs[i]);
97}
98
99static 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(irq: keypad->row_irqs[i]);
105}
106
107static 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 */
120static 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, on: 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(desc: 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, on: true);
145
146 new_state[col] = read_row_state(keypad);
147
148 activate_col(keypad, col, on: 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(dev: input_dev, EV_MSC, MSC_SCAN, value: code);
164 input_report_key(dev: input_dev,
165 code: keycodes[code],
166 value: new_state[col] & (1 << row));
167 }
168 }
169 input_sync(dev: input_dev);
170
171 memcpy(keypad->last_key_state, new_state, sizeof(new_state));
172
173 activate_all_cols(keypad, on: 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)(l: &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(dwork: &keypad->work,
190 delay: msecs_to_jiffies(m: keypad->debounce_ms));
191 }
192}
193
194static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
195{
196 struct matrix_keypad *keypad = id;
197
198 guard(spinlock_irqsave)(l: &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(dwork: &keypad->work,
211 delay: msecs_to_jiffies(m: keypad->debounce_ms));
212
213out:
214 return IRQ_HANDLED;
215}
216
217static 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(dwork: &keypad->work, delay: 0);
229
230 return 0;
231}
232
233static 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(dwork: &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
249static 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(irq: keypad->row_irqs[i]) == 0)
256 __set_bit(i, keypad->wakeup_enabled_irqs);
257}
258
259static 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(irq: keypad->row_irqs[i]);
266 __clear_bit(i, keypad->wakeup_enabled_irqs);
267 }
268}
269
270static 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(dev: keypad->input_dev);
276
277 if (device_may_wakeup(dev: &pdev->dev))
278 matrix_keypad_enable_wakeup(keypad);
279
280 return 0;
281}
282
283static 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(dev: &pdev->dev))
289 matrix_keypad_disable_wakeup(keypad);
290
291 matrix_keypad_start(dev: keypad->input_dev);
292
293 return 0;
294}
295
296static DEFINE_SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
297 matrix_keypad_suspend, matrix_keypad_resume);
298
299static 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(dev: &pdev->dev, con_id: "row");
308 ncol = gpiod_count(dev: &pdev->dev, con_id: "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(dev: &pdev->dev, propname: "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(dev: &pdev->dev, con_id: "col",
322 idx: i, flags: GPIOD_ASIS);
323 err = PTR_ERR_OR_ZERO(ptr: 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(desc: keypad->col_gpios[i], name: "matrix_kbd_col");
332
333 if (active_low ^ gpiod_is_active_low(desc: keypad->col_gpios[i]))
334 gpiod_toggle_active_low(desc: keypad->col_gpios[i]);
335
336 gpiod_direction_output(desc: keypad->col_gpios[i], value: 1);
337 }
338
339 for (i = 0; i < keypad->num_row_gpios; i++) {
340 keypad->row_gpios[i] = devm_gpiod_get_index(dev: &pdev->dev, con_id: "row",
341 idx: i, flags: GPIOD_IN);
342 err = PTR_ERR_OR_ZERO(ptr: 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(desc: keypad->row_gpios[i], name: "matrix_kbd_row");
351
352 if (active_low ^ gpiod_is_active_low(desc: keypad->row_gpios[i]))
353 gpiod_toggle_active_low(desc: keypad->row_gpios[i]);
354 }
355
356 return 0;
357}
358
359static 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(desc: 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(dev: &pdev->dev, irq,
377 handler: matrix_keypad_interrupt,
378 IRQF_TRIGGER_RISING |
379 IRQF_TRIGGER_FALLING,
380 devname: "matrix-keypad", dev_id: 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
397static 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(dev: &pdev->dev, size: 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(dev: &pdev->dev, propname: "drive-inactive-cols");
419 device_property_read_u32(dev: &pdev->dev, propname: "debounce-delay-ms",
420 val: &keypad->debounce_ms);
421 device_property_read_u32(dev: &pdev->dev, propname: "col-scan-delay-us",
422 val: &keypad->col_scan_delay_us);
423 device_property_read_u32(dev: &pdev->dev, propname: "all-cols-on-delay-us",
424 val: &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(count: 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 rows: keypad->num_row_gpios,
443 cols: 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(dev: &pdev->dev, propname: "linux,no-autorepeat"))
451 __set_bit(EV_REP, input_dev->evbit);
452
453 input_set_capability(dev: input_dev, EV_MSC, MSC_SCAN);
454 input_set_drvdata(dev: input_dev, data: keypad);
455
456 err = input_register_device(keypad->input_dev);
457 if (err)
458 return err;
459
460 wakeup = device_property_read_bool(dev: &pdev->dev, propname: "wakeup-source") ||
461 /* legacy */
462 device_property_read_bool(dev: &pdev->dev, propname: "linux,wakeup");
463 device_init_wakeup(dev: &pdev->dev, enable: wakeup);
464
465 platform_set_drvdata(pdev, data: keypad);
466
467 return 0;
468}
469
470#ifdef CONFIG_OF
471static const struct of_device_id matrix_keypad_dt_match[] = {
472 { .compatible = "gpio-matrix-keypad" },
473 { }
474};
475MODULE_DEVICE_TABLE(of, matrix_keypad_dt_match);
476#endif
477
478static 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};
486module_platform_driver(matrix_keypad_driver);
487
488MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
489MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
490MODULE_LICENSE("GPL v2");
491MODULE_ALIAS("platform:matrix-keypad");
492

source code of linux/drivers/input/keyboard/matrix_keypad.c