1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Keyboard class input driver for the NVIDIA Tegra SoC internal matrix
4  * keyboard controller
5  *
6  * Copyright (c) 2009-2011, NVIDIA Corporation.
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/input.h>
12 #include <linux/platform_device.h>
13 #include <linux/delay.h>
14 #include <linux/io.h>
15 #include <linux/interrupt.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/clk.h>
19 #include <linux/slab.h>
20 #include <linux/input/matrix_keypad.h>
21 #include <linux/reset.h>
22 #include <linux/err.h>
23 
24 #define KBC_MAX_KPENT	8
25 
26 /* Maximum row/column supported by Tegra KBC yet  is 16x8 */
27 #define KBC_MAX_GPIO	24
28 /* Maximum keys supported by Tegra KBC yet is 16 x 8*/
29 #define KBC_MAX_KEY	(16 * 8)
30 
31 #define KBC_MAX_DEBOUNCE_CNT	0x3ffu
32 
33 /* KBC row scan time and delay for beginning the row scan. */
34 #define KBC_ROW_SCAN_TIME	16
35 #define KBC_ROW_SCAN_DLY	5
36 
37 /* KBC uses a 32KHz clock so a cycle = 1/32Khz */
38 #define KBC_CYCLE_MS	32
39 
40 /* KBC Registers */
41 
42 /* KBC Control Register */
43 #define KBC_CONTROL_0	0x0
44 #define KBC_FIFO_TH_CNT_SHIFT(cnt)	(cnt << 14)
45 #define KBC_DEBOUNCE_CNT_SHIFT(cnt)	(cnt << 4)
46 #define KBC_CONTROL_FIFO_CNT_INT_EN	(1 << 3)
47 #define KBC_CONTROL_KEYPRESS_INT_EN	(1 << 1)
48 #define KBC_CONTROL_KBC_EN		(1 << 0)
49 
50 /* KBC Interrupt Register */
51 #define KBC_INT_0	0x4
52 #define KBC_INT_FIFO_CNT_INT_STATUS	(1 << 2)
53 #define KBC_INT_KEYPRESS_INT_STATUS	(1 << 0)
54 
55 #define KBC_ROW_CFG0_0	0x8
56 #define KBC_COL_CFG0_0	0x18
57 #define KBC_TO_CNT_0	0x24
58 #define KBC_INIT_DLY_0	0x28
59 #define KBC_RPT_DLY_0	0x2c
60 #define KBC_KP_ENT0_0	0x30
61 #define KBC_KP_ENT1_0	0x34
62 #define KBC_ROW0_MASK_0	0x38
63 
64 #define KBC_ROW_SHIFT	3
65 
66 enum tegra_pin_type {
67 	PIN_CFG_IGNORE,
68 	PIN_CFG_COL,
69 	PIN_CFG_ROW,
70 };
71 
72 /* Tegra KBC hw support */
73 struct tegra_kbc_hw_support {
74 	int max_rows;
75 	int max_columns;
76 };
77 
78 struct tegra_kbc_pin_cfg {
79 	enum tegra_pin_type type;
80 	unsigned char num;
81 };
82 
83 struct tegra_kbc {
84 	struct device *dev;
85 	unsigned int debounce_cnt;
86 	unsigned int repeat_cnt;
87 	struct tegra_kbc_pin_cfg pin_cfg[KBC_MAX_GPIO];
88 	const struct matrix_keymap_data *keymap_data;
89 	bool wakeup;
90 	void __iomem *mmio;
91 	struct input_dev *idev;
92 	int irq;
93 	spinlock_t lock;
94 	unsigned int repoll_dly;
95 	unsigned long cp_dly_jiffies;
96 	unsigned int cp_to_wkup_dly;
97 	bool use_fn_map;
98 	bool use_ghost_filter;
99 	bool keypress_caused_wake;
100 	unsigned short keycode[KBC_MAX_KEY * 2];
101 	unsigned short current_keys[KBC_MAX_KPENT];
102 	unsigned int num_pressed_keys;
103 	u32 wakeup_key;
104 	struct timer_list timer;
105 	struct clk *clk;
106 	struct reset_control *rst;
107 	const struct tegra_kbc_hw_support *hw_support;
108 	int max_keys;
109 	int num_rows_and_columns;
110 };
111 
112 static void tegra_kbc_report_released_keys(struct input_dev *input,
113 					   unsigned short old_keycodes[],
114 					   unsigned int old_num_keys,
115 					   unsigned short new_keycodes[],
116 					   unsigned int new_num_keys)
117 {
118 	unsigned int i, j;
119 
120 	for (i = 0; i < old_num_keys; i++) {
121 		for (j = 0; j < new_num_keys; j++)
122 			if (old_keycodes[i] == new_keycodes[j])
123 				break;
124 
125 		if (j == new_num_keys)
126 			input_report_key(input, old_keycodes[i], 0);
127 	}
128 }
129 
130 static void tegra_kbc_report_pressed_keys(struct input_dev *input,
131 					  unsigned char scancodes[],
132 					  unsigned short keycodes[],
133 					  unsigned int num_pressed_keys)
134 {
135 	unsigned int i;
136 
137 	for (i = 0; i < num_pressed_keys; i++) {
138 		input_event(input, EV_MSC, MSC_SCAN, scancodes[i]);
139 		input_report_key(input, keycodes[i], 1);
140 	}
141 }
142 
143 static void tegra_kbc_report_keys(struct tegra_kbc *kbc)
144 {
145 	unsigned char scancodes[KBC_MAX_KPENT];
146 	unsigned short keycodes[KBC_MAX_KPENT];
147 	u32 val = 0;
148 	unsigned int i;
149 	unsigned int num_down = 0;
150 	bool fn_keypress = false;
151 	bool key_in_same_row = false;
152 	bool key_in_same_col = false;
153 
154 	for (i = 0; i < KBC_MAX_KPENT; i++) {
155 		if ((i % 4) == 0)
156 			val = readl(kbc->mmio + KBC_KP_ENT0_0 + i);
157 
158 		if (val & 0x80) {
159 			unsigned int col = val & 0x07;
160 			unsigned int row = (val >> 3) & 0x0f;
161 			unsigned char scancode =
162 				MATRIX_SCAN_CODE(row, col, KBC_ROW_SHIFT);
163 
164 			scancodes[num_down] = scancode;
165 			keycodes[num_down] = kbc->keycode[scancode];
166 			/* If driver uses Fn map, do not report the Fn key. */
167 			if ((keycodes[num_down] == KEY_FN) && kbc->use_fn_map)
168 				fn_keypress = true;
169 			else
170 				num_down++;
171 		}
172 
173 		val >>= 8;
174 	}
175 
176 	/*
177 	 * Matrix keyboard designs are prone to keyboard ghosting.
178 	 * Ghosting occurs if there are 3 keys such that -
179 	 * any 2 of the 3 keys share a row, and any 2 of them share a column.
180 	 * If so ignore the key presses for this iteration.
181 	 */
182 	if (kbc->use_ghost_filter && num_down >= 3) {
183 		for (i = 0; i < num_down; i++) {
184 			unsigned int j;
185 			u8 curr_col = scancodes[i] & 0x07;
186 			u8 curr_row = scancodes[i] >> KBC_ROW_SHIFT;
187 
188 			/*
189 			 * Find 2 keys such that one key is in the same row
190 			 * and the other is in the same column as the i-th key.
191 			 */
192 			for (j = i + 1; j < num_down; j++) {
193 				u8 col = scancodes[j] & 0x07;
194 				u8 row = scancodes[j] >> KBC_ROW_SHIFT;
195 
196 				if (col == curr_col)
197 					key_in_same_col = true;
198 				if (row == curr_row)
199 					key_in_same_row = true;
200 			}
201 		}
202 	}
203 
204 	/*
205 	 * If the platform uses Fn keymaps, translate keys on a Fn keypress.
206 	 * Function keycodes are max_keys apart from the plain keycodes.
207 	 */
208 	if (fn_keypress) {
209 		for (i = 0; i < num_down; i++) {
210 			scancodes[i] += kbc->max_keys;
211 			keycodes[i] = kbc->keycode[scancodes[i]];
212 		}
213 	}
214 
215 	/* Ignore the key presses for this iteration? */
216 	if (key_in_same_col && key_in_same_row)
217 		return;
218 
219 	tegra_kbc_report_released_keys(kbc->idev,
220 				       kbc->current_keys, kbc->num_pressed_keys,
221 				       keycodes, num_down);
222 	tegra_kbc_report_pressed_keys(kbc->idev, scancodes, keycodes, num_down);
223 	input_sync(kbc->idev);
224 
225 	memcpy(kbc->current_keys, keycodes, sizeof(kbc->current_keys));
226 	kbc->num_pressed_keys = num_down;
227 }
228 
229 static void tegra_kbc_set_fifo_interrupt(struct tegra_kbc *kbc, bool enable)
230 {
231 	u32 val;
232 
233 	val = readl(kbc->mmio + KBC_CONTROL_0);
234 	if (enable)
235 		val |= KBC_CONTROL_FIFO_CNT_INT_EN;
236 	else
237 		val &= ~KBC_CONTROL_FIFO_CNT_INT_EN;
238 	writel(val, kbc->mmio + KBC_CONTROL_0);
239 }
240 
241 static void tegra_kbc_keypress_timer(struct timer_list *t)
242 {
243 	struct tegra_kbc *kbc = from_timer(kbc, t, timer);
244 	unsigned long flags;
245 	u32 val;
246 	unsigned int i;
247 
248 	spin_lock_irqsave(&kbc->lock, flags);
249 
250 	val = (readl(kbc->mmio + KBC_INT_0) >> 4) & 0xf;
251 	if (val) {
252 		unsigned long dly;
253 
254 		tegra_kbc_report_keys(kbc);
255 
256 		/*
257 		 * If more than one keys are pressed we need not wait
258 		 * for the repoll delay.
259 		 */
260 		dly = (val == 1) ? kbc->repoll_dly : 1;
261 		mod_timer(&kbc->timer, jiffies + msecs_to_jiffies(dly));
262 	} else {
263 		/* Release any pressed keys and exit the polling loop */
264 		for (i = 0; i < kbc->num_pressed_keys; i++)
265 			input_report_key(kbc->idev, kbc->current_keys[i], 0);
266 		input_sync(kbc->idev);
267 
268 		kbc->num_pressed_keys = 0;
269 
270 		/* All keys are released so enable the keypress interrupt */
271 		tegra_kbc_set_fifo_interrupt(kbc, true);
272 	}
273 
274 	spin_unlock_irqrestore(&kbc->lock, flags);
275 }
276 
277 static irqreturn_t tegra_kbc_isr(int irq, void *args)
278 {
279 	struct tegra_kbc *kbc = args;
280 	unsigned long flags;
281 	u32 val;
282 
283 	spin_lock_irqsave(&kbc->lock, flags);
284 
285 	/*
286 	 * Quickly bail out & reenable interrupts if the fifo threshold
287 	 * count interrupt wasn't the interrupt source
288 	 */
289 	val = readl(kbc->mmio + KBC_INT_0);
290 	writel(val, kbc->mmio + KBC_INT_0);
291 
292 	if (val & KBC_INT_FIFO_CNT_INT_STATUS) {
293 		/*
294 		 * Until all keys are released, defer further processing to
295 		 * the polling loop in tegra_kbc_keypress_timer.
296 		 */
297 		tegra_kbc_set_fifo_interrupt(kbc, false);
298 		mod_timer(&kbc->timer, jiffies + kbc->cp_dly_jiffies);
299 	} else if (val & KBC_INT_KEYPRESS_INT_STATUS) {
300 		/* We can be here only through system resume path */
301 		kbc->keypress_caused_wake = true;
302 	}
303 
304 	spin_unlock_irqrestore(&kbc->lock, flags);
305 
306 	return IRQ_HANDLED;
307 }
308 
309 static void tegra_kbc_setup_wakekeys(struct tegra_kbc *kbc, bool filter)
310 {
311 	int i;
312 	unsigned int rst_val;
313 
314 	/* Either mask all keys or none. */
315 	rst_val = (filter && !kbc->wakeup) ? ~0 : 0;
316 
317 	for (i = 0; i < kbc->hw_support->max_rows; i++)
318 		writel(rst_val, kbc->mmio + KBC_ROW0_MASK_0 + i * 4);
319 }
320 
321 static void tegra_kbc_config_pins(struct tegra_kbc *kbc)
322 {
323 	int i;
324 
325 	for (i = 0; i < KBC_MAX_GPIO; i++) {
326 		u32 r_shft = 5 * (i % 6);
327 		u32 c_shft = 4 * (i % 8);
328 		u32 r_mask = 0x1f << r_shft;
329 		u32 c_mask = 0x0f << c_shft;
330 		u32 r_offs = (i / 6) * 4 + KBC_ROW_CFG0_0;
331 		u32 c_offs = (i / 8) * 4 + KBC_COL_CFG0_0;
332 		u32 row_cfg = readl(kbc->mmio + r_offs);
333 		u32 col_cfg = readl(kbc->mmio + c_offs);
334 
335 		row_cfg &= ~r_mask;
336 		col_cfg &= ~c_mask;
337 
338 		switch (kbc->pin_cfg[i].type) {
339 		case PIN_CFG_ROW:
340 			row_cfg |= ((kbc->pin_cfg[i].num << 1) | 1) << r_shft;
341 			break;
342 
343 		case PIN_CFG_COL:
344 			col_cfg |= ((kbc->pin_cfg[i].num << 1) | 1) << c_shft;
345 			break;
346 
347 		case PIN_CFG_IGNORE:
348 			break;
349 		}
350 
351 		writel(row_cfg, kbc->mmio + r_offs);
352 		writel(col_cfg, kbc->mmio + c_offs);
353 	}
354 }
355 
356 static int tegra_kbc_start(struct tegra_kbc *kbc)
357 {
358 	unsigned int debounce_cnt;
359 	u32 val = 0;
360 	int ret;
361 
362 	ret = clk_prepare_enable(kbc->clk);
363 	if (ret)
364 		return ret;
365 
366 	/* Reset the KBC controller to clear all previous status.*/
367 	reset_control_assert(kbc->rst);
368 	udelay(100);
369 	reset_control_deassert(kbc->rst);
370 	udelay(100);
371 
372 	tegra_kbc_config_pins(kbc);
373 	tegra_kbc_setup_wakekeys(kbc, false);
374 
375 	writel(kbc->repeat_cnt, kbc->mmio + KBC_RPT_DLY_0);
376 
377 	/* Keyboard debounce count is maximum of 12 bits. */
378 	debounce_cnt = min(kbc->debounce_cnt, KBC_MAX_DEBOUNCE_CNT);
379 	val = KBC_DEBOUNCE_CNT_SHIFT(debounce_cnt);
380 	val |= KBC_FIFO_TH_CNT_SHIFT(1); /* set fifo interrupt threshold to 1 */
381 	val |= KBC_CONTROL_FIFO_CNT_INT_EN;  /* interrupt on FIFO threshold */
382 	val |= KBC_CONTROL_KBC_EN;     /* enable */
383 	writel(val, kbc->mmio + KBC_CONTROL_0);
384 
385 	/*
386 	 * Compute the delay(ns) from interrupt mode to continuous polling
387 	 * mode so the timer routine is scheduled appropriately.
388 	 */
389 	val = readl(kbc->mmio + KBC_INIT_DLY_0);
390 	kbc->cp_dly_jiffies = usecs_to_jiffies((val & 0xfffff) * 32);
391 
392 	kbc->num_pressed_keys = 0;
393 
394 	/*
395 	 * Atomically clear out any remaining entries in the key FIFO
396 	 * and enable keyboard interrupts.
397 	 */
398 	while (1) {
399 		val = readl(kbc->mmio + KBC_INT_0);
400 		val >>= 4;
401 		if (!val)
402 			break;
403 
404 		val = readl(kbc->mmio + KBC_KP_ENT0_0);
405 		val = readl(kbc->mmio + KBC_KP_ENT1_0);
406 	}
407 	writel(0x7, kbc->mmio + KBC_INT_0);
408 
409 	enable_irq(kbc->irq);
410 
411 	return 0;
412 }
413 
414 static void tegra_kbc_stop(struct tegra_kbc *kbc)
415 {
416 	unsigned long flags;
417 	u32 val;
418 
419 	spin_lock_irqsave(&kbc->lock, flags);
420 	val = readl(kbc->mmio + KBC_CONTROL_0);
421 	val &= ~1;
422 	writel(val, kbc->mmio + KBC_CONTROL_0);
423 	spin_unlock_irqrestore(&kbc->lock, flags);
424 
425 	disable_irq(kbc->irq);
426 	del_timer_sync(&kbc->timer);
427 
428 	clk_disable_unprepare(kbc->clk);
429 }
430 
431 static int tegra_kbc_open(struct input_dev *dev)
432 {
433 	struct tegra_kbc *kbc = input_get_drvdata(dev);
434 
435 	return tegra_kbc_start(kbc);
436 }
437 
438 static void tegra_kbc_close(struct input_dev *dev)
439 {
440 	struct tegra_kbc *kbc = input_get_drvdata(dev);
441 
442 	return tegra_kbc_stop(kbc);
443 }
444 
445 static bool tegra_kbc_check_pin_cfg(const struct tegra_kbc *kbc,
446 					unsigned int *num_rows)
447 {
448 	int i;
449 
450 	*num_rows = 0;
451 
452 	for (i = 0; i < KBC_MAX_GPIO; i++) {
453 		const struct tegra_kbc_pin_cfg *pin_cfg = &kbc->pin_cfg[i];
454 
455 		switch (pin_cfg->type) {
456 		case PIN_CFG_ROW:
457 			if (pin_cfg->num >= kbc->hw_support->max_rows) {
458 				dev_err(kbc->dev,
459 					"pin_cfg[%d]: invalid row number %d\n",
460 					i, pin_cfg->num);
461 				return false;
462 			}
463 			(*num_rows)++;
464 			break;
465 
466 		case PIN_CFG_COL:
467 			if (pin_cfg->num >= kbc->hw_support->max_columns) {
468 				dev_err(kbc->dev,
469 					"pin_cfg[%d]: invalid column number %d\n",
470 					i, pin_cfg->num);
471 				return false;
472 			}
473 			break;
474 
475 		case PIN_CFG_IGNORE:
476 			break;
477 
478 		default:
479 			dev_err(kbc->dev,
480 				"pin_cfg[%d]: invalid entry type %d\n",
481 				pin_cfg->type, pin_cfg->num);
482 			return false;
483 		}
484 	}
485 
486 	return true;
487 }
488 
489 static int tegra_kbc_parse_dt(struct tegra_kbc *kbc)
490 {
491 	struct device_node *np = kbc->dev->of_node;
492 	u32 prop;
493 	int i;
494 	u32 num_rows = 0;
495 	u32 num_cols = 0;
496 	u32 cols_cfg[KBC_MAX_GPIO];
497 	u32 rows_cfg[KBC_MAX_GPIO];
498 	int proplen;
499 	int ret;
500 
501 	if (!of_property_read_u32(np, "nvidia,debounce-delay-ms", &prop))
502 		kbc->debounce_cnt = prop;
503 
504 	if (!of_property_read_u32(np, "nvidia,repeat-delay-ms", &prop))
505 		kbc->repeat_cnt = prop;
506 
507 	if (of_find_property(np, "nvidia,needs-ghost-filter", NULL))
508 		kbc->use_ghost_filter = true;
509 
510 	if (of_property_read_bool(np, "wakeup-source") ||
511 	    of_property_read_bool(np, "nvidia,wakeup-source")) /* legacy */
512 		kbc->wakeup = true;
513 
514 	if (!of_get_property(np, "nvidia,kbc-row-pins", &proplen)) {
515 		dev_err(kbc->dev, "property nvidia,kbc-row-pins not found\n");
516 		return -ENOENT;
517 	}
518 	num_rows = proplen / sizeof(u32);
519 
520 	if (!of_get_property(np, "nvidia,kbc-col-pins", &proplen)) {
521 		dev_err(kbc->dev, "property nvidia,kbc-col-pins not found\n");
522 		return -ENOENT;
523 	}
524 	num_cols = proplen / sizeof(u32);
525 
526 	if (num_rows > kbc->hw_support->max_rows) {
527 		dev_err(kbc->dev,
528 			"Number of rows is more than supported by hardware\n");
529 		return -EINVAL;
530 	}
531 
532 	if (num_cols > kbc->hw_support->max_columns) {
533 		dev_err(kbc->dev,
534 			"Number of cols is more than supported by hardware\n");
535 		return -EINVAL;
536 	}
537 
538 	if (!of_get_property(np, "linux,keymap", &proplen)) {
539 		dev_err(kbc->dev, "property linux,keymap not found\n");
540 		return -ENOENT;
541 	}
542 
543 	if (!num_rows || !num_cols || ((num_rows + num_cols) > KBC_MAX_GPIO)) {
544 		dev_err(kbc->dev,
545 			"keypad rows/columns not properly specified\n");
546 		return -EINVAL;
547 	}
548 
549 	/* Set all pins as non-configured */
550 	for (i = 0; i < kbc->num_rows_and_columns; i++)
551 		kbc->pin_cfg[i].type = PIN_CFG_IGNORE;
552 
553 	ret = of_property_read_u32_array(np, "nvidia,kbc-row-pins",
554 				rows_cfg, num_rows);
555 	if (ret < 0) {
556 		dev_err(kbc->dev, "Rows configurations are not proper\n");
557 		return -EINVAL;
558 	}
559 
560 	ret = of_property_read_u32_array(np, "nvidia,kbc-col-pins",
561 				cols_cfg, num_cols);
562 	if (ret < 0) {
563 		dev_err(kbc->dev, "Cols configurations are not proper\n");
564 		return -EINVAL;
565 	}
566 
567 	for (i = 0; i < num_rows; i++) {
568 		kbc->pin_cfg[rows_cfg[i]].type = PIN_CFG_ROW;
569 		kbc->pin_cfg[rows_cfg[i]].num = i;
570 	}
571 
572 	for (i = 0; i < num_cols; i++) {
573 		kbc->pin_cfg[cols_cfg[i]].type = PIN_CFG_COL;
574 		kbc->pin_cfg[cols_cfg[i]].num = i;
575 	}
576 
577 	return 0;
578 }
579 
580 static const struct tegra_kbc_hw_support tegra20_kbc_hw_support = {
581 	.max_rows	= 16,
582 	.max_columns	= 8,
583 };
584 
585 static const struct tegra_kbc_hw_support tegra11_kbc_hw_support = {
586 	.max_rows	= 11,
587 	.max_columns	= 8,
588 };
589 
590 static const struct of_device_id tegra_kbc_of_match[] = {
591 	{ .compatible = "nvidia,tegra114-kbc", .data = &tegra11_kbc_hw_support},
592 	{ .compatible = "nvidia,tegra30-kbc", .data = &tegra20_kbc_hw_support},
593 	{ .compatible = "nvidia,tegra20-kbc", .data = &tegra20_kbc_hw_support},
594 	{ },
595 };
596 MODULE_DEVICE_TABLE(of, tegra_kbc_of_match);
597 
598 static int tegra_kbc_probe(struct platform_device *pdev)
599 {
600 	struct tegra_kbc *kbc;
601 	struct resource *res;
602 	int err;
603 	int num_rows = 0;
604 	unsigned int debounce_cnt;
605 	unsigned int scan_time_rows;
606 	unsigned int keymap_rows;
607 	const struct of_device_id *match;
608 
609 	match = of_match_device(tegra_kbc_of_match, &pdev->dev);
610 
611 	kbc = devm_kzalloc(&pdev->dev, sizeof(*kbc), GFP_KERNEL);
612 	if (!kbc) {
613 		dev_err(&pdev->dev, "failed to alloc memory for kbc\n");
614 		return -ENOMEM;
615 	}
616 
617 	kbc->dev = &pdev->dev;
618 	kbc->hw_support = match->data;
619 	kbc->max_keys = kbc->hw_support->max_rows *
620 				kbc->hw_support->max_columns;
621 	kbc->num_rows_and_columns = kbc->hw_support->max_rows +
622 					kbc->hw_support->max_columns;
623 	keymap_rows = kbc->max_keys;
624 	spin_lock_init(&kbc->lock);
625 
626 	err = tegra_kbc_parse_dt(kbc);
627 	if (err)
628 		return err;
629 
630 	if (!tegra_kbc_check_pin_cfg(kbc, &num_rows))
631 		return -EINVAL;
632 
633 	kbc->irq = platform_get_irq(pdev, 0);
634 	if (kbc->irq < 0)
635 		return -ENXIO;
636 
637 	kbc->idev = devm_input_allocate_device(&pdev->dev);
638 	if (!kbc->idev) {
639 		dev_err(&pdev->dev, "failed to allocate input device\n");
640 		return -ENOMEM;
641 	}
642 
643 	timer_setup(&kbc->timer, tegra_kbc_keypress_timer, 0);
644 
645 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
646 	kbc->mmio = devm_ioremap_resource(&pdev->dev, res);
647 	if (IS_ERR(kbc->mmio))
648 		return PTR_ERR(kbc->mmio);
649 
650 	kbc->clk = devm_clk_get(&pdev->dev, NULL);
651 	if (IS_ERR(kbc->clk)) {
652 		dev_err(&pdev->dev, "failed to get keyboard clock\n");
653 		return PTR_ERR(kbc->clk);
654 	}
655 
656 	kbc->rst = devm_reset_control_get(&pdev->dev, "kbc");
657 	if (IS_ERR(kbc->rst)) {
658 		dev_err(&pdev->dev, "failed to get keyboard reset\n");
659 		return PTR_ERR(kbc->rst);
660 	}
661 
662 	/*
663 	 * The time delay between two consecutive reads of the FIFO is
664 	 * the sum of the repeat time and the time taken for scanning
665 	 * the rows. There is an additional delay before the row scanning
666 	 * starts. The repoll delay is computed in milliseconds.
667 	 */
668 	debounce_cnt = min(kbc->debounce_cnt, KBC_MAX_DEBOUNCE_CNT);
669 	scan_time_rows = (KBC_ROW_SCAN_TIME + debounce_cnt) * num_rows;
670 	kbc->repoll_dly = KBC_ROW_SCAN_DLY + scan_time_rows + kbc->repeat_cnt;
671 	kbc->repoll_dly = DIV_ROUND_UP(kbc->repoll_dly, KBC_CYCLE_MS);
672 
673 	kbc->idev->name = pdev->name;
674 	kbc->idev->id.bustype = BUS_HOST;
675 	kbc->idev->dev.parent = &pdev->dev;
676 	kbc->idev->open = tegra_kbc_open;
677 	kbc->idev->close = tegra_kbc_close;
678 
679 	if (kbc->keymap_data && kbc->use_fn_map)
680 		keymap_rows *= 2;
681 
682 	err = matrix_keypad_build_keymap(kbc->keymap_data, NULL,
683 					 keymap_rows,
684 					 kbc->hw_support->max_columns,
685 					 kbc->keycode, kbc->idev);
686 	if (err) {
687 		dev_err(&pdev->dev, "failed to setup keymap\n");
688 		return err;
689 	}
690 
691 	__set_bit(EV_REP, kbc->idev->evbit);
692 	input_set_capability(kbc->idev, EV_MSC, MSC_SCAN);
693 
694 	input_set_drvdata(kbc->idev, kbc);
695 
696 	err = devm_request_irq(&pdev->dev, kbc->irq, tegra_kbc_isr,
697 			       IRQF_TRIGGER_HIGH | IRQF_NO_AUTOEN,
698 			       pdev->name, kbc);
699 	if (err) {
700 		dev_err(&pdev->dev, "failed to request keyboard IRQ\n");
701 		return err;
702 	}
703 
704 	err = input_register_device(kbc->idev);
705 	if (err) {
706 		dev_err(&pdev->dev, "failed to register input device\n");
707 		return err;
708 	}
709 
710 	platform_set_drvdata(pdev, kbc);
711 	device_init_wakeup(&pdev->dev, kbc->wakeup);
712 
713 	return 0;
714 }
715 
716 static void tegra_kbc_set_keypress_interrupt(struct tegra_kbc *kbc, bool enable)
717 {
718 	u32 val;
719 
720 	val = readl(kbc->mmio + KBC_CONTROL_0);
721 	if (enable)
722 		val |= KBC_CONTROL_KEYPRESS_INT_EN;
723 	else
724 		val &= ~KBC_CONTROL_KEYPRESS_INT_EN;
725 	writel(val, kbc->mmio + KBC_CONTROL_0);
726 }
727 
728 static int tegra_kbc_suspend(struct device *dev)
729 {
730 	struct platform_device *pdev = to_platform_device(dev);
731 	struct tegra_kbc *kbc = platform_get_drvdata(pdev);
732 
733 	mutex_lock(&kbc->idev->mutex);
734 	if (device_may_wakeup(&pdev->dev)) {
735 		disable_irq(kbc->irq);
736 		del_timer_sync(&kbc->timer);
737 		tegra_kbc_set_fifo_interrupt(kbc, false);
738 
739 		/* Forcefully clear the interrupt status */
740 		writel(0x7, kbc->mmio + KBC_INT_0);
741 		/*
742 		 * Store the previous resident time of continuous polling mode.
743 		 * Force the keyboard into interrupt mode.
744 		 */
745 		kbc->cp_to_wkup_dly = readl(kbc->mmio + KBC_TO_CNT_0);
746 		writel(0, kbc->mmio + KBC_TO_CNT_0);
747 
748 		tegra_kbc_setup_wakekeys(kbc, true);
749 		msleep(30);
750 
751 		kbc->keypress_caused_wake = false;
752 		/* Enable keypress interrupt before going into suspend. */
753 		tegra_kbc_set_keypress_interrupt(kbc, true);
754 		enable_irq(kbc->irq);
755 		enable_irq_wake(kbc->irq);
756 	} else {
757 		if (input_device_enabled(kbc->idev))
758 			tegra_kbc_stop(kbc);
759 	}
760 	mutex_unlock(&kbc->idev->mutex);
761 
762 	return 0;
763 }
764 
765 static int tegra_kbc_resume(struct device *dev)
766 {
767 	struct platform_device *pdev = to_platform_device(dev);
768 	struct tegra_kbc *kbc = platform_get_drvdata(pdev);
769 	int err = 0;
770 
771 	mutex_lock(&kbc->idev->mutex);
772 	if (device_may_wakeup(&pdev->dev)) {
773 		disable_irq_wake(kbc->irq);
774 		tegra_kbc_setup_wakekeys(kbc, false);
775 		/* We will use fifo interrupts for key detection. */
776 		tegra_kbc_set_keypress_interrupt(kbc, false);
777 
778 		/* Restore the resident time of continuous polling mode. */
779 		writel(kbc->cp_to_wkup_dly, kbc->mmio + KBC_TO_CNT_0);
780 
781 		tegra_kbc_set_fifo_interrupt(kbc, true);
782 
783 		if (kbc->keypress_caused_wake && kbc->wakeup_key) {
784 			/*
785 			 * We can't report events directly from the ISR
786 			 * because timekeeping is stopped when processing
787 			 * wakeup request and we get a nasty warning when
788 			 * we try to call do_gettimeofday() in evdev
789 			 * handler.
790 			 */
791 			input_report_key(kbc->idev, kbc->wakeup_key, 1);
792 			input_sync(kbc->idev);
793 			input_report_key(kbc->idev, kbc->wakeup_key, 0);
794 			input_sync(kbc->idev);
795 		}
796 	} else {
797 		if (input_device_enabled(kbc->idev))
798 			err = tegra_kbc_start(kbc);
799 	}
800 	mutex_unlock(&kbc->idev->mutex);
801 
802 	return err;
803 }
804 
805 static DEFINE_SIMPLE_DEV_PM_OPS(tegra_kbc_pm_ops,
806 				tegra_kbc_suspend, tegra_kbc_resume);
807 
808 static struct platform_driver tegra_kbc_driver = {
809 	.probe		= tegra_kbc_probe,
810 	.driver	= {
811 		.name	= "tegra-kbc",
812 		.pm	= pm_sleep_ptr(&tegra_kbc_pm_ops),
813 		.of_match_table = tegra_kbc_of_match,
814 	},
815 };
816 module_platform_driver(tegra_kbc_driver);
817 
818 MODULE_LICENSE("GPL");
819 MODULE_AUTHOR("Rakesh Iyer <riyer@nvidia.com>");
820 MODULE_DESCRIPTION("Tegra matrix keyboard controller driver");
821 MODULE_ALIAS("platform:tegra-kbc");
822