2 * Driver for the IMX keypad port.
3 * Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * <<Power management needs to be implemented>>.
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/init.h>
17 #include <linux/input/matrix_keypad.h>
18 #include <linux/interrupt.h>
20 #include <linux/jiffies.h>
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/platform_device.h>
24 #include <linux/slab.h>
25 #include <linux/timer.h>
28 * Keypad Controller registers (halfword)
30 #define KPCR 0x00 /* Keypad Control Register */
32 #define KPSR 0x02 /* Keypad Status Register */
33 #define KBD_STAT_KPKD (0x1 << 0) /* Key Press Interrupt Status bit (w1c) */
34 #define KBD_STAT_KPKR (0x1 << 1) /* Key Release Interrupt Status bit (w1c) */
35 #define KBD_STAT_KDSC (0x1 << 2) /* Key Depress Synch Chain Status bit (w1c)*/
36 #define KBD_STAT_KRSS (0x1 << 3) /* Key Release Synch Status bit (w1c)*/
37 #define KBD_STAT_KDIE (0x1 << 8) /* Key Depress Interrupt Enable Status bit */
38 #define KBD_STAT_KRIE (0x1 << 9) /* Key Release Interrupt Enable */
39 #define KBD_STAT_KPPEN (0x1 << 10) /* Keypad Clock Enable */
41 #define KDDR 0x04 /* Keypad Data Direction Register */
42 #define KPDR 0x06 /* Keypad Data Register */
44 #define MAX_MATRIX_KEY_ROWS 8
45 #define MAX_MATRIX_KEY_COLS 8
46 #define MATRIX_ROW_SHIFT 3
48 #define MAX_MATRIX_KEY_NUM (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS)
53 struct input_dev *input_dev;
54 void __iomem *mmio_base;
57 struct timer_list check_matrix_timer;
60 * The matrix is stable only if no changes are detected after
61 * IMX_KEYPAD_SCANS_FOR_STABILITY scans
63 #define IMX_KEYPAD_SCANS_FOR_STABILITY 3
68 /* Masks for enabled rows/cols */
69 unsigned short rows_en_mask;
70 unsigned short cols_en_mask;
72 unsigned short keycodes[MAX_MATRIX_KEY_NUM];
76 * -stable: achieved after a complete debounce process.
77 * -unstable: used in the debouncing process.
79 unsigned short matrix_stable_state[MAX_MATRIX_KEY_COLS];
80 unsigned short matrix_unstable_state[MAX_MATRIX_KEY_COLS];
83 /* Scan the matrix and return the new state in *matrix_volatile_state. */
84 static void imx_keypad_scan_matrix(struct imx_keypad *keypad,
85 unsigned short *matrix_volatile_state)
88 unsigned short reg_val;
90 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
91 if ((keypad->cols_en_mask & (1 << col)) == 0)
94 * Discharge keypad capacitance:
95 * 2. write 1s on column data.
96 * 3. configure columns as totem-pole to discharge capacitance.
97 * 4. configure columns as open-drain.
99 reg_val = readw(keypad->mmio_base + KPDR);
101 writew(reg_val, keypad->mmio_base + KPDR);
103 reg_val = readw(keypad->mmio_base + KPCR);
104 reg_val &= ~((keypad->cols_en_mask & 0xff) << 8);
105 writew(reg_val, keypad->mmio_base + KPCR);
109 reg_val = readw(keypad->mmio_base + KPCR);
110 reg_val |= (keypad->cols_en_mask & 0xff) << 8;
111 writew(reg_val, keypad->mmio_base + KPCR);
114 * 5. Write a single column to 0, others to 1.
115 * 6. Sample row inputs and save data.
116 * 7. Repeat steps 2 - 6 for remaining columns.
118 reg_val = readw(keypad->mmio_base + KPDR);
119 reg_val &= ~(1 << (8 + col));
120 writew(reg_val, keypad->mmio_base + KPDR);
123 * Delay added to avoid propagating the 0 from column to row
129 * 1s in matrix_volatile_state[col] means key pressures
130 * throw data from non enabled rows.
132 reg_val = readw(keypad->mmio_base + KPDR);
133 matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask;
137 * Return in standby mode:
138 * 9. write 0s to columns
140 reg_val = readw(keypad->mmio_base + KPDR);
142 writew(reg_val, keypad->mmio_base + KPDR);
146 * Compare the new matrix state (volatile) with the stable one stored in
147 * keypad->matrix_stable_state and fire events if changes are detected.
149 static void imx_keypad_fire_events(struct imx_keypad *keypad,
150 unsigned short *matrix_volatile_state)
152 struct input_dev *input_dev = keypad->input_dev;
155 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
156 unsigned short bits_changed;
159 if ((keypad->cols_en_mask & (1 << col)) == 0)
160 continue; /* Column is not enabled */
162 bits_changed = keypad->matrix_stable_state[col] ^
163 matrix_volatile_state[col];
165 if (bits_changed == 0)
166 continue; /* Column does not contain changes */
168 for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
169 if ((keypad->rows_en_mask & (1 << row)) == 0)
170 continue; /* Row is not enabled */
171 if ((bits_changed & (1 << row)) == 0)
172 continue; /* Row does not contain changes */
174 code = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
175 input_event(input_dev, EV_MSC, MSC_SCAN, code);
176 input_report_key(input_dev, keypad->keycodes[code],
177 matrix_volatile_state[col] & (1 << row));
178 dev_dbg(&input_dev->dev, "Event code: %d, val: %d",
179 keypad->keycodes[code],
180 matrix_volatile_state[col] & (1 << row));
183 input_sync(input_dev);
187 * imx_keypad_check_for_events is the timer handler.
189 static void imx_keypad_check_for_events(unsigned long data)
191 struct imx_keypad *keypad = (struct imx_keypad *) data;
192 unsigned short matrix_volatile_state[MAX_MATRIX_KEY_COLS];
193 unsigned short reg_val;
194 bool state_changed, is_zero_matrix;
197 memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state));
199 imx_keypad_scan_matrix(keypad, matrix_volatile_state);
201 state_changed = false;
202 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
203 if ((keypad->cols_en_mask & (1 << i)) == 0)
206 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) {
207 state_changed = true;
213 * If the matrix state is changed from the previous scan
214 * (Re)Begin the debouncing process, saving the new state in
215 * keypad->matrix_unstable_state.
217 * Increase the count of number of scans with a stable state.
220 memcpy(keypad->matrix_unstable_state, matrix_volatile_state,
221 sizeof(matrix_volatile_state));
222 keypad->stable_count = 0;
224 keypad->stable_count++;
227 * If the matrix is not as stable as we want reschedule scan
228 * in the near future.
230 if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) {
231 mod_timer(&keypad->check_matrix_timer,
232 jiffies + msecs_to_jiffies(10));
237 * If the matrix state is stable, fire the events and save the new
238 * stable state. Note, if the matrix is kept stable for longer
239 * (keypad->stable_count > IMX_KEYPAD_SCANS_FOR_STABILITY) all
240 * events have already been generated.
242 if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) {
243 imx_keypad_fire_events(keypad, matrix_volatile_state);
245 memcpy(keypad->matrix_stable_state, matrix_volatile_state,
246 sizeof(matrix_volatile_state));
249 is_zero_matrix = true;
250 for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
251 if (matrix_volatile_state[i] != 0) {
252 is_zero_matrix = false;
258 if (is_zero_matrix) {
260 * All keys have been released. Enable only the KDI
261 * interrupt for future key presses (clear the KDI
262 * status bit and its sync chain before that).
264 reg_val = readw(keypad->mmio_base + KPSR);
265 reg_val |= KBD_STAT_KPKD | KBD_STAT_KDSC;
266 writew(reg_val, keypad->mmio_base + KPSR);
268 reg_val = readw(keypad->mmio_base + KPSR);
269 reg_val |= KBD_STAT_KDIE;
270 reg_val &= ~KBD_STAT_KRIE;
271 writew(reg_val, keypad->mmio_base + KPSR);
274 * Some keys are still pressed. Schedule a rescan in
275 * attempt to detect multiple key presses and enable
276 * the KRI interrupt to react quickly to key release
279 mod_timer(&keypad->check_matrix_timer,
280 jiffies + msecs_to_jiffies(60));
282 reg_val = readw(keypad->mmio_base + KPSR);
283 reg_val |= KBD_STAT_KPKR | KBD_STAT_KRSS;
284 writew(reg_val, keypad->mmio_base + KPSR);
286 reg_val = readw(keypad->mmio_base + KPSR);
287 reg_val |= KBD_STAT_KRIE;
288 reg_val &= ~KBD_STAT_KDIE;
289 writew(reg_val, keypad->mmio_base + KPSR);
293 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id)
295 struct imx_keypad *keypad = dev_id;
296 unsigned short reg_val;
298 reg_val = readw(keypad->mmio_base + KPSR);
300 /* Disable both interrupt types */
301 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
302 /* Clear interrupts status bits */
303 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
304 writew(reg_val, keypad->mmio_base + KPSR);
306 if (keypad->enabled) {
307 /* The matrix is supposed to be changed */
308 keypad->stable_count = 0;
310 /* Schedule the scanning procedure near in the future */
311 mod_timer(&keypad->check_matrix_timer,
312 jiffies + msecs_to_jiffies(2));
318 static void imx_keypad_config(struct imx_keypad *keypad)
320 unsigned short reg_val;
323 * Include enabled rows in interrupt generation (KPCR[7:0])
324 * Configure keypad columns as open-drain (KPCR[15:8])
326 reg_val = readw(keypad->mmio_base + KPCR);
327 reg_val |= keypad->rows_en_mask & 0xff; /* rows */
328 reg_val |= (keypad->cols_en_mask & 0xff) << 8; /* cols */
329 writew(reg_val, keypad->mmio_base + KPCR);
331 /* Write 0's to KPDR[15:8] (Colums) */
332 reg_val = readw(keypad->mmio_base + KPDR);
334 writew(reg_val, keypad->mmio_base + KPDR);
336 /* Configure columns as output, rows as input (KDDR[15:0]) */
337 writew(0xff00, keypad->mmio_base + KDDR);
340 * Clear Key Depress and Key Release status bit.
341 * Clear both synchronizer chain.
343 reg_val = readw(keypad->mmio_base + KPSR);
344 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD |
345 KBD_STAT_KDSC | KBD_STAT_KRSS;
346 writew(reg_val, keypad->mmio_base + KPSR);
348 /* Enable KDI and disable KRI (avoid false release events). */
349 reg_val |= KBD_STAT_KDIE;
350 reg_val &= ~KBD_STAT_KRIE;
351 writew(reg_val, keypad->mmio_base + KPSR);
354 static void imx_keypad_inhibit(struct imx_keypad *keypad)
356 unsigned short reg_val;
358 /* Inhibit KDI and KRI interrupts. */
359 reg_val = readw(keypad->mmio_base + KPSR);
360 reg_val &= ~(KBD_STAT_KRIE | KBD_STAT_KDIE);
361 reg_val |= KBD_STAT_KPKR | KBD_STAT_KPKD;
362 writew(reg_val, keypad->mmio_base + KPSR);
364 /* Colums as open drain and disable all rows */
365 reg_val = (keypad->cols_en_mask & 0xff) << 8;
366 writew(reg_val, keypad->mmio_base + KPCR);
369 static void imx_keypad_close(struct input_dev *dev)
371 struct imx_keypad *keypad = input_get_drvdata(dev);
373 dev_dbg(&dev->dev, ">%s\n", __func__);
375 /* Mark keypad as being inactive */
376 keypad->enabled = false;
377 synchronize_irq(keypad->irq);
378 del_timer_sync(&keypad->check_matrix_timer);
380 imx_keypad_inhibit(keypad);
382 /* Disable clock unit */
383 clk_disable_unprepare(keypad->clk);
386 static int imx_keypad_open(struct input_dev *dev)
388 struct imx_keypad *keypad = input_get_drvdata(dev);
391 dev_dbg(&dev->dev, ">%s\n", __func__);
393 /* Enable the kpp clock */
394 error = clk_prepare_enable(keypad->clk);
398 /* We became active from now */
399 keypad->enabled = true;
401 imx_keypad_config(keypad);
403 /* Sanity control, not all the rows must be actived now. */
404 if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) {
406 "too many keys pressed, control pins initialisation\n");
413 imx_keypad_close(dev);
417 static int imx_keypad_probe(struct platform_device *pdev)
419 const struct matrix_keymap_data *keymap_data = pdev->dev.platform_data;
420 struct imx_keypad *keypad;
421 struct input_dev *input_dev;
422 struct resource *res;
425 if (keymap_data == NULL) {
426 dev_err(&pdev->dev, "no keymap defined\n");
430 irq = platform_get_irq(pdev, 0);
432 dev_err(&pdev->dev, "no irq defined in platform data\n");
436 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
438 dev_err(&pdev->dev, "no I/O memory defined in platform data\n");
442 res = request_mem_region(res->start, resource_size(res), pdev->name);
444 dev_err(&pdev->dev, "failed to request I/O memory\n");
448 input_dev = input_allocate_device();
450 dev_err(&pdev->dev, "failed to allocate the input device\n");
455 keypad = kzalloc(sizeof(struct imx_keypad), GFP_KERNEL);
457 dev_err(&pdev->dev, "not enough memory for driver data\n");
459 goto failed_free_input;
462 keypad->input_dev = input_dev;
464 keypad->stable_count = 0;
466 setup_timer(&keypad->check_matrix_timer,
467 imx_keypad_check_for_events, (unsigned long) keypad);
469 keypad->mmio_base = ioremap(res->start, resource_size(res));
470 if (keypad->mmio_base == NULL) {
471 dev_err(&pdev->dev, "failed to remap I/O memory\n");
473 goto failed_free_priv;
476 keypad->clk = clk_get(&pdev->dev, NULL);
477 if (IS_ERR(keypad->clk)) {
478 dev_err(&pdev->dev, "failed to get keypad clock\n");
479 error = PTR_ERR(keypad->clk);
483 /* Search for rows and cols enabled */
484 for (i = 0; i < keymap_data->keymap_size; i++) {
485 keypad->rows_en_mask |= 1 << KEY_ROW(keymap_data->keymap[i]);
486 keypad->cols_en_mask |= 1 << KEY_COL(keymap_data->keymap[i]);
489 if (keypad->rows_en_mask > ((1 << MAX_MATRIX_KEY_ROWS) - 1) ||
490 keypad->cols_en_mask > ((1 << MAX_MATRIX_KEY_COLS) - 1)) {
492 "invalid key data (too many rows or colums)\n");
494 goto failed_clock_put;
496 dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask);
497 dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask);
499 /* Init the Input device */
500 input_dev->name = pdev->name;
501 input_dev->id.bustype = BUS_HOST;
502 input_dev->dev.parent = &pdev->dev;
503 input_dev->open = imx_keypad_open;
504 input_dev->close = imx_keypad_close;
506 error = matrix_keypad_build_keymap(keymap_data, NULL,
509 keypad->keycodes, input_dev);
511 dev_err(&pdev->dev, "failed to build keymap\n");
512 goto failed_clock_put;
515 __set_bit(EV_REP, input_dev->evbit);
516 input_set_capability(input_dev, EV_MSC, MSC_SCAN);
517 input_set_drvdata(input_dev, keypad);
519 /* Ensure that the keypad will stay dormant until opened */
520 clk_prepare_enable(keypad->clk);
521 imx_keypad_inhibit(keypad);
522 clk_disable_unprepare(keypad->clk);
524 error = request_irq(irq, imx_keypad_irq_handler, 0,
527 dev_err(&pdev->dev, "failed to request IRQ\n");
528 goto failed_clock_put;
531 /* Register the input device */
532 error = input_register_device(input_dev);
534 dev_err(&pdev->dev, "failed to register input device\n");
535 goto failed_free_irq;
538 platform_set_drvdata(pdev, keypad);
539 device_init_wakeup(&pdev->dev, 1);
546 clk_put(keypad->clk);
548 iounmap(keypad->mmio_base);
552 input_free_device(input_dev);
554 release_mem_region(res->start, resource_size(res));
558 static int imx_keypad_remove(struct platform_device *pdev)
560 struct imx_keypad *keypad = platform_get_drvdata(pdev);
561 struct resource *res;
563 dev_dbg(&pdev->dev, ">%s\n", __func__);
565 platform_set_drvdata(pdev, NULL);
567 input_unregister_device(keypad->input_dev);
569 free_irq(keypad->irq, keypad);
570 clk_put(keypad->clk);
572 iounmap(keypad->mmio_base);
573 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
574 release_mem_region(res->start, resource_size(res));
581 #ifdef CONFIG_PM_SLEEP
582 static int imx_kbd_suspend(struct device *dev)
584 struct platform_device *pdev = to_platform_device(dev);
585 struct imx_keypad *kbd = platform_get_drvdata(pdev);
586 struct input_dev *input_dev = kbd->input_dev;
588 /* imx kbd can wake up system even clock is disabled */
589 mutex_lock(&input_dev->mutex);
591 if (input_dev->users)
592 clk_disable_unprepare(kbd->clk);
594 mutex_unlock(&input_dev->mutex);
596 if (device_may_wakeup(&pdev->dev))
597 enable_irq_wake(kbd->irq);
602 static int imx_kbd_resume(struct device *dev)
604 struct platform_device *pdev = to_platform_device(dev);
605 struct imx_keypad *kbd = platform_get_drvdata(pdev);
606 struct input_dev *input_dev = kbd->input_dev;
609 if (device_may_wakeup(&pdev->dev))
610 disable_irq_wake(kbd->irq);
612 mutex_lock(&input_dev->mutex);
614 if (input_dev->users) {
615 ret = clk_prepare_enable(kbd->clk);
621 mutex_unlock(&input_dev->mutex);
627 static SIMPLE_DEV_PM_OPS(imx_kbd_pm_ops, imx_kbd_suspend, imx_kbd_resume);
629 static struct platform_driver imx_keypad_driver = {
631 .name = "imx-keypad",
632 .owner = THIS_MODULE,
633 .pm = &imx_kbd_pm_ops,
635 .probe = imx_keypad_probe,
636 .remove = imx_keypad_remove,
638 module_platform_driver(imx_keypad_driver);
640 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
641 MODULE_DESCRIPTION("IMX Keypad Port Driver");
642 MODULE_LICENSE("GPL v2");
643 MODULE_ALIAS("platform:imx-keypad");