Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/input/keyboard/imx_keypad.c

  1 /*
  2  * Driver for the IMX keypad port.
  3  * Copyright (C) 2009 Alberto Panizzo <maramaopercheseimorto@gmail.com>
  4  *
  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.
  8  *
  9  * <<Power management needs to be implemented>>.
 10  */
 11 
 12 #include <linux/clk.h>
 13 #include <linux/delay.h>
 14 #include <linux/device.h>
 15 #include <linux/err.h>
 16 #include <linux/input/matrix_keypad.h>
 17 #include <linux/interrupt.h>
 18 #include <linux/io.h>
 19 #include <linux/jiffies.h>
 20 #include <linux/kernel.h>
 21 #include <linux/module.h>
 22 #include <linux/of.h>
 23 #include <linux/platform_device.h>
 24 #include <linux/slab.h>
 25 #include <linux/timer.h>
 26 
 27 /*
 28  * Keypad Controller registers (halfword)
 29  */
 30 #define KPCR            0x00 /* Keypad Control Register */
 31 
 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 */
 40 
 41 #define KDDR            0x04 /* Keypad Data Direction Register */
 42 #define KPDR            0x06 /* Keypad Data Register */
 43 
 44 #define MAX_MATRIX_KEY_ROWS     8
 45 #define MAX_MATRIX_KEY_COLS     8
 46 #define MATRIX_ROW_SHIFT        3
 47 
 48 #define MAX_MATRIX_KEY_NUM      (MAX_MATRIX_KEY_ROWS * MAX_MATRIX_KEY_COLS)
 49 
 50 struct imx_keypad {
 51 
 52         struct clk *clk;
 53         struct input_dev *input_dev;
 54         void __iomem *mmio_base;
 55 
 56         int                     irq;
 57         struct timer_list       check_matrix_timer;
 58 
 59         /*
 60          * The matrix is stable only if no changes are detected after
 61          * IMX_KEYPAD_SCANS_FOR_STABILITY scans
 62          */
 63 #define IMX_KEYPAD_SCANS_FOR_STABILITY 3
 64         int                     stable_count;
 65 
 66         bool                    enabled;
 67 
 68         /* Masks for enabled rows/cols */
 69         unsigned short          rows_en_mask;
 70         unsigned short          cols_en_mask;
 71 
 72         unsigned short          keycodes[MAX_MATRIX_KEY_NUM];
 73 
 74         /*
 75          * Matrix states:
 76          * -stable: achieved after a complete debounce process.
 77          * -unstable: used in the debouncing process.
 78          */
 79         unsigned short          matrix_stable_state[MAX_MATRIX_KEY_COLS];
 80         unsigned short          matrix_unstable_state[MAX_MATRIX_KEY_COLS];
 81 };
 82 
 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)
 86 {
 87         int col;
 88         unsigned short reg_val;
 89 
 90         for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
 91                 if ((keypad->cols_en_mask & (1 << col)) == 0)
 92                         continue;
 93                 /*
 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.
 98                  */
 99                 reg_val = readw(keypad->mmio_base + KPDR);
100                 reg_val |= 0xff00;
101                 writew(reg_val, keypad->mmio_base + KPDR);
102 
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);
106 
107                 udelay(2);
108 
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);
112 
113                 /*
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.
117                  */
118                 reg_val = readw(keypad->mmio_base + KPDR);
119                 reg_val &= ~(1 << (8 + col));
120                 writew(reg_val, keypad->mmio_base + KPDR);
121 
122                 /*
123                  * Delay added to avoid propagating the 0 from column to row
124                  * when scanning.
125                  */
126                 udelay(5);
127 
128                 /*
129                  * 1s in matrix_volatile_state[col] means key pressures
130                  * throw data from non enabled rows.
131                  */
132                 reg_val = readw(keypad->mmio_base + KPDR);
133                 matrix_volatile_state[col] = (~reg_val) & keypad->rows_en_mask;
134         }
135 
136         /*
137          * Return in standby mode:
138          * 9. write 0s to columns
139          */
140         reg_val = readw(keypad->mmio_base + KPDR);
141         reg_val &= 0x00ff;
142         writew(reg_val, keypad->mmio_base + KPDR);
143 }
144 
145 /*
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.
148  */
149 static void imx_keypad_fire_events(struct imx_keypad *keypad,
150                                    unsigned short *matrix_volatile_state)
151 {
152         struct input_dev *input_dev = keypad->input_dev;
153         int row, col;
154 
155         for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
156                 unsigned short bits_changed;
157                 int code;
158 
159                 if ((keypad->cols_en_mask & (1 << col)) == 0)
160                         continue; /* Column is not enabled */
161 
162                 bits_changed = keypad->matrix_stable_state[col] ^
163                                                 matrix_volatile_state[col];
164 
165                 if (bits_changed == 0)
166                         continue; /* Column does not contain changes */
167 
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 */
173 
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));
181                 }
182         }
183         input_sync(input_dev);
184 }
185 
186 /*
187  * imx_keypad_check_for_events is the timer handler.
188  */
189 static void imx_keypad_check_for_events(unsigned long data)
190 {
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;
195         int i;
196 
197         memset(matrix_volatile_state, 0, sizeof(matrix_volatile_state));
198 
199         imx_keypad_scan_matrix(keypad, matrix_volatile_state);
200 
201         state_changed = false;
202         for (i = 0; i < MAX_MATRIX_KEY_COLS; i++) {
203                 if ((keypad->cols_en_mask & (1 << i)) == 0)
204                         continue;
205 
206                 if (keypad->matrix_unstable_state[i] ^ matrix_volatile_state[i]) {
207                         state_changed = true;
208                         break;
209                 }
210         }
211 
212         /*
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.
216          * else
217          *   Increase the count of number of scans with a stable state.
218          */
219         if (state_changed) {
220                 memcpy(keypad->matrix_unstable_state, matrix_volatile_state,
221                         sizeof(matrix_volatile_state));
222                 keypad->stable_count = 0;
223         } else
224                 keypad->stable_count++;
225 
226         /*
227          * If the matrix is not as stable as we want reschedule scan
228          * in the near future.
229          */
230         if (keypad->stable_count < IMX_KEYPAD_SCANS_FOR_STABILITY) {
231                 mod_timer(&keypad->check_matrix_timer,
232                           jiffies + msecs_to_jiffies(10));
233                 return;
234         }
235 
236         /*
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.
241          */
242         if (keypad->stable_count == IMX_KEYPAD_SCANS_FOR_STABILITY) {
243                 imx_keypad_fire_events(keypad, matrix_volatile_state);
244 
245                 memcpy(keypad->matrix_stable_state, matrix_volatile_state,
246                         sizeof(matrix_volatile_state));
247         }
248 
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;
253                         break;
254                 }
255         }
256 
257 
258         if (is_zero_matrix) {
259                 /*
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).
263                  */
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);
267 
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);
272         } else {
273                 /*
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
277                  * event.
278                  */
279                 mod_timer(&keypad->check_matrix_timer,
280                           jiffies + msecs_to_jiffies(60));
281 
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);
285 
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);
290         }
291 }
292 
293 static irqreturn_t imx_keypad_irq_handler(int irq, void *dev_id)
294 {
295         struct imx_keypad *keypad = dev_id;
296         unsigned short reg_val;
297 
298         reg_val = readw(keypad->mmio_base + KPSR);
299 
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);
305 
306         if (keypad->enabled) {
307                 /* The matrix is supposed to be changed */
308                 keypad->stable_count = 0;
309 
310                 /* Schedule the scanning procedure near in the future */
311                 mod_timer(&keypad->check_matrix_timer,
312                           jiffies + msecs_to_jiffies(2));
313         }
314 
315         return IRQ_HANDLED;
316 }
317 
318 static void imx_keypad_config(struct imx_keypad *keypad)
319 {
320         unsigned short reg_val;
321 
322         /*
323          * Include enabled rows in interrupt generation (KPCR[7:0])
324          * Configure keypad columns as open-drain (KPCR[15:8])
325          */
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);
330 
331         /* Write 0's to KPDR[15:8] (Colums) */
332         reg_val = readw(keypad->mmio_base + KPDR);
333         reg_val &= 0x00ff;
334         writew(reg_val, keypad->mmio_base + KPDR);
335 
336         /* Configure columns as output, rows as input (KDDR[15:0]) */
337         writew(0xff00, keypad->mmio_base + KDDR);
338 
339         /*
340          * Clear Key Depress and Key Release status bit.
341          * Clear both synchronizer chain.
342          */
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);
347 
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);
352 }
353 
354 static void imx_keypad_inhibit(struct imx_keypad *keypad)
355 {
356         unsigned short reg_val;
357 
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);
363 
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);
367 }
368 
369 static void imx_keypad_close(struct input_dev *dev)
370 {
371         struct imx_keypad *keypad = input_get_drvdata(dev);
372 
373         dev_dbg(&dev->dev, ">%s\n", __func__);
374 
375         /* Mark keypad as being inactive */
376         keypad->enabled = false;
377         synchronize_irq(keypad->irq);
378         del_timer_sync(&keypad->check_matrix_timer);
379 
380         imx_keypad_inhibit(keypad);
381 
382         /* Disable clock unit */
383         clk_disable_unprepare(keypad->clk);
384 }
385 
386 static int imx_keypad_open(struct input_dev *dev)
387 {
388         struct imx_keypad *keypad = input_get_drvdata(dev);
389         int error;
390 
391         dev_dbg(&dev->dev, ">%s\n", __func__);
392 
393         /* Enable the kpp clock */
394         error = clk_prepare_enable(keypad->clk);
395         if (error)
396                 return error;
397 
398         /* We became active from now */
399         keypad->enabled = true;
400 
401         imx_keypad_config(keypad);
402 
403         /* Sanity control, not all the rows must be actived now. */
404         if ((readw(keypad->mmio_base + KPDR) & keypad->rows_en_mask) == 0) {
405                 dev_err(&dev->dev,
406                         "too many keys pressed, control pins initialisation\n");
407                 goto open_err;
408         }
409 
410         return 0;
411 
412 open_err:
413         imx_keypad_close(dev);
414         return -EIO;
415 }
416 
417 #ifdef CONFIG_OF
418 static const struct of_device_id imx_keypad_of_match[] = {
419         { .compatible = "fsl,imx21-kpp", },
420         { /* sentinel */ }
421 };
422 MODULE_DEVICE_TABLE(of, imx_keypad_of_match);
423 #endif
424 
425 static int imx_keypad_probe(struct platform_device *pdev)
426 {
427         const struct matrix_keymap_data *keymap_data =
428                         dev_get_platdata(&pdev->dev);
429         struct imx_keypad *keypad;
430         struct input_dev *input_dev;
431         struct resource *res;
432         int irq, error, i, row, col;
433 
434         if (!keymap_data && !pdev->dev.of_node) {
435                 dev_err(&pdev->dev, "no keymap defined\n");
436                 return -EINVAL;
437         }
438 
439         irq = platform_get_irq(pdev, 0);
440         if (irq < 0) {
441                 dev_err(&pdev->dev, "no irq defined in platform data\n");
442                 return irq;
443         }
444 
445         input_dev = devm_input_allocate_device(&pdev->dev);
446         if (!input_dev) {
447                 dev_err(&pdev->dev, "failed to allocate the input device\n");
448                 return -ENOMEM;
449         }
450 
451         keypad = devm_kzalloc(&pdev->dev, sizeof(struct imx_keypad),
452                               GFP_KERNEL);
453         if (!keypad) {
454                 dev_err(&pdev->dev, "not enough memory for driver data\n");
455                 return -ENOMEM;
456         }
457 
458         keypad->input_dev = input_dev;
459         keypad->irq = irq;
460         keypad->stable_count = 0;
461 
462         setup_timer(&keypad->check_matrix_timer,
463                     imx_keypad_check_for_events, (unsigned long) keypad);
464 
465         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
466         keypad->mmio_base = devm_ioremap_resource(&pdev->dev, res);
467         if (IS_ERR(keypad->mmio_base))
468                 return PTR_ERR(keypad->mmio_base);
469 
470         keypad->clk = devm_clk_get(&pdev->dev, NULL);
471         if (IS_ERR(keypad->clk)) {
472                 dev_err(&pdev->dev, "failed to get keypad clock\n");
473                 return PTR_ERR(keypad->clk);
474         }
475 
476         /* Init the Input device */
477         input_dev->name = pdev->name;
478         input_dev->id.bustype = BUS_HOST;
479         input_dev->dev.parent = &pdev->dev;
480         input_dev->open = imx_keypad_open;
481         input_dev->close = imx_keypad_close;
482 
483         error = matrix_keypad_build_keymap(keymap_data, NULL,
484                                            MAX_MATRIX_KEY_ROWS,
485                                            MAX_MATRIX_KEY_COLS,
486                                            keypad->keycodes, input_dev);
487         if (error) {
488                 dev_err(&pdev->dev, "failed to build keymap\n");
489                 return error;
490         }
491 
492         /* Search for rows and cols enabled */
493         for (row = 0; row < MAX_MATRIX_KEY_ROWS; row++) {
494                 for (col = 0; col < MAX_MATRIX_KEY_COLS; col++) {
495                         i = MATRIX_SCAN_CODE(row, col, MATRIX_ROW_SHIFT);
496                         if (keypad->keycodes[i] != KEY_RESERVED) {
497                                 keypad->rows_en_mask |= 1 << row;
498                                 keypad->cols_en_mask |= 1 << col;
499                         }
500                 }
501         }
502         dev_dbg(&pdev->dev, "enabled rows mask: %x\n", keypad->rows_en_mask);
503         dev_dbg(&pdev->dev, "enabled cols mask: %x\n", keypad->cols_en_mask);
504 
505         __set_bit(EV_REP, input_dev->evbit);
506         input_set_capability(input_dev, EV_MSC, MSC_SCAN);
507         input_set_drvdata(input_dev, keypad);
508 
509         /* Ensure that the keypad will stay dormant until opened */
510         clk_prepare_enable(keypad->clk);
511         imx_keypad_inhibit(keypad);
512         clk_disable_unprepare(keypad->clk);
513 
514         error = devm_request_irq(&pdev->dev, irq, imx_keypad_irq_handler, 0,
515                             pdev->name, keypad);
516         if (error) {
517                 dev_err(&pdev->dev, "failed to request IRQ\n");
518                 return error;
519         }
520 
521         /* Register the input device */
522         error = input_register_device(input_dev);
523         if (error) {
524                 dev_err(&pdev->dev, "failed to register input device\n");
525                 return error;
526         }
527 
528         platform_set_drvdata(pdev, keypad);
529         device_init_wakeup(&pdev->dev, 1);
530 
531         return 0;
532 }
533 
534 static int __maybe_unused imx_kbd_suspend(struct device *dev)
535 {
536         struct platform_device *pdev = to_platform_device(dev);
537         struct imx_keypad *kbd = platform_get_drvdata(pdev);
538         struct input_dev *input_dev = kbd->input_dev;
539 
540         /* imx kbd can wake up system even clock is disabled */
541         mutex_lock(&input_dev->mutex);
542 
543         if (input_dev->users)
544                 clk_disable_unprepare(kbd->clk);
545 
546         mutex_unlock(&input_dev->mutex);
547 
548         if (device_may_wakeup(&pdev->dev))
549                 enable_irq_wake(kbd->irq);
550 
551         return 0;
552 }
553 
554 static int __maybe_unused imx_kbd_resume(struct device *dev)
555 {
556         struct platform_device *pdev = to_platform_device(dev);
557         struct imx_keypad *kbd = platform_get_drvdata(pdev);
558         struct input_dev *input_dev = kbd->input_dev;
559         int ret = 0;
560 
561         if (device_may_wakeup(&pdev->dev))
562                 disable_irq_wake(kbd->irq);
563 
564         mutex_lock(&input_dev->mutex);
565 
566         if (input_dev->users) {
567                 ret = clk_prepare_enable(kbd->clk);
568                 if (ret)
569                         goto err_clk;
570         }
571 
572 err_clk:
573         mutex_unlock(&input_dev->mutex);
574 
575         return ret;
576 }
577 
578 static SIMPLE_DEV_PM_OPS(imx_kbd_pm_ops, imx_kbd_suspend, imx_kbd_resume);
579 
580 static struct platform_driver imx_keypad_driver = {
581         .driver         = {
582                 .name   = "imx-keypad",
583                 .owner  = THIS_MODULE,
584                 .pm     = &imx_kbd_pm_ops,
585                 .of_match_table = of_match_ptr(imx_keypad_of_match),
586         },
587         .probe          = imx_keypad_probe,
588 };
589 module_platform_driver(imx_keypad_driver);
590 
591 MODULE_AUTHOR("Alberto Panizzo <maramaopercheseimorto@gmail.com>");
592 MODULE_DESCRIPTION("IMX Keypad Port Driver");
593 MODULE_LICENSE("GPL v2");
594 MODULE_ALIAS("platform:imx-keypad");
595 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us