summaryrefslogtreecommitdiff
path: root/drivers/gpio/gpio-aspeed.c
blob: ccea609676eebfe8bbcd6e01acaa8f6c4499ffe7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
/*
 * Copyright 2015 IBM Corp.
 *
 * Joel Stanley <joel@jms.id.au>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <asm/div64.h>
#include <linux/clk.h>
#include <linux/gpio/driver.h>
#include <linux/hashtable.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/string.h>

struct aspeed_bank_props {
	unsigned int bank;
	u32 input;
	u32 output;
};

struct aspeed_gpio_config {
	unsigned int nr_gpios;
	const struct aspeed_bank_props *props;
};

/*
 * @offset_timer: Maps an offset to an @timer_users index, or zero if disabled
 * @timer_users: Tracks the number of users for each timer
 *
 * The @timer_users has four elements but the first element is unused. This is
 * to simplify accounting and indexing, as a zero value in @offset_timer
 * represents disabled debouncing for the GPIO. Any other value for an element
 * of @offset_timer is used as an index into @timer_users. This behaviour of
 * the zero value aligns with the behaviour of zero built from the timer
 * configuration registers (i.e. debouncing is disabled).
 */
struct aspeed_gpio {
	struct gpio_chip chip;
	spinlock_t lock;
	void __iomem *base;
	int irq;
	const struct aspeed_gpio_config *config;

	u8 *offset_timer;
	unsigned int timer_users[4];
	struct clk *clk;
};

struct aspeed_gpio_bank {
	uint16_t	val_regs;
	uint16_t	irq_regs;
	uint16_t	debounce_regs;
	const char	names[4][3];
};

static const int debounce_timers[4] = { 0x00, 0x50, 0x54, 0x58 };

static const struct aspeed_gpio_bank aspeed_gpio_banks[] = {
	{
		.val_regs = 0x0000,
		.irq_regs = 0x0008,
		.debounce_regs = 0x0040,
		.names = { "A", "B", "C", "D" },
	},
	{
		.val_regs = 0x0020,
		.irq_regs = 0x0028,
		.debounce_regs = 0x0048,
		.names = { "E", "F", "G", "H" },
	},
	{
		.val_regs = 0x0070,
		.irq_regs = 0x0098,
		.debounce_regs = 0x00b0,
		.names = { "I", "J", "K", "L" },
	},
	{
		.val_regs = 0x0078,
		.irq_regs = 0x00e8,
		.debounce_regs = 0x0100,
		.names = { "M", "N", "O", "P" },
	},
	{
		.val_regs = 0x0080,
		.irq_regs = 0x0118,
		.debounce_regs = 0x0130,
		.names = { "Q", "R", "S", "T" },
	},
	{
		.val_regs = 0x0088,
		.irq_regs = 0x0148,
		.debounce_regs = 0x0160,
		.names = { "U", "V", "W", "X" },
	},
	{
		.val_regs = 0x01E0,
		.irq_regs = 0x0178,
		.debounce_regs = 0x0190,
		.names = { "Y", "Z", "AA", "AB" },
	},
	{
		.val_regs = 0x01E8,
		.irq_regs = 0x01A8,
		.debounce_regs = 0x01c0,
		.names = { "AC", "", "", "" },
	},
};

#define GPIO_BANK(x)	((x) >> 5)
#define GPIO_OFFSET(x)	((x) & 0x1f)
#define GPIO_BIT(x)	BIT(GPIO_OFFSET(x))

#define GPIO_DATA	0x00
#define GPIO_DIR	0x04

#define GPIO_IRQ_ENABLE	0x00
#define GPIO_IRQ_TYPE0	0x04
#define GPIO_IRQ_TYPE1	0x08
#define GPIO_IRQ_TYPE2	0x0c
#define GPIO_IRQ_STATUS	0x10

#define GPIO_DEBOUNCE_SEL1 0x00
#define GPIO_DEBOUNCE_SEL2 0x04

#define _GPIO_SET_DEBOUNCE(t, o, i) ((!!((t) & BIT(i))) << GPIO_OFFSET(o))
#define GPIO_SET_DEBOUNCE1(t, o) _GPIO_SET_DEBOUNCE(t, o, 1)
#define GPIO_SET_DEBOUNCE2(t, o) _GPIO_SET_DEBOUNCE(t, o, 0)

static const struct aspeed_gpio_bank *to_bank(unsigned int offset)
{
	unsigned int bank = GPIO_BANK(offset);

	WARN_ON(bank > ARRAY_SIZE(aspeed_gpio_banks));
	return &aspeed_gpio_banks[bank];
}

static inline bool is_bank_props_sentinel(const struct aspeed_bank_props *props)
{
	return !(props->input || props->output);
}

static inline const struct aspeed_bank_props *find_bank_props(
		struct aspeed_gpio *gpio, unsigned int offset)
{
	const struct aspeed_bank_props *props = gpio->config->props;

	while (!is_bank_props_sentinel(props)) {
		if (props->bank == GPIO_BANK(offset))
			return props;
		props++;
	}

	return NULL;
}

static inline bool have_gpio(struct aspeed_gpio *gpio, unsigned int offset)
{
	const struct aspeed_bank_props *props = find_bank_props(gpio, offset);
	const struct aspeed_gpio_bank *bank = to_bank(offset);
	unsigned int group = GPIO_OFFSET(offset) / 8;

	return bank->names[group][0] != '\0' &&
		(!props || ((props->input | props->output) & GPIO_BIT(offset)));
}

static inline bool have_input(struct aspeed_gpio *gpio, unsigned int offset)
{
	const struct aspeed_bank_props *props = find_bank_props(gpio, offset);

	return !props || (props->input & GPIO_BIT(offset));
}

#define have_irq(g, o) have_input((g), (o))
#define have_debounce(g, o) have_input((g), (o))

static inline bool have_output(struct aspeed_gpio *gpio, unsigned int offset)
{
	const struct aspeed_bank_props *props = find_bank_props(gpio, offset);

	return !props || (props->output & GPIO_BIT(offset));
}

static void __iomem *bank_val_reg(struct aspeed_gpio *gpio,
		const struct aspeed_gpio_bank *bank,
		unsigned int reg)
{
	return gpio->base + bank->val_regs + reg;
}

static void __iomem *bank_irq_reg(struct aspeed_gpio *gpio,
		const struct aspeed_gpio_bank *bank,
		unsigned int reg)
{
	return gpio->base + bank->irq_regs + reg;
}

static int aspeed_gpio_get(struct gpio_chip *gc, unsigned int offset)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
	const struct aspeed_gpio_bank *bank = to_bank(offset);

	return !!(ioread32(bank_val_reg(gpio, bank, GPIO_DATA))
			& GPIO_BIT(offset));
}

static void __aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
			      int val)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
	const struct aspeed_gpio_bank *bank = to_bank(offset);
	void __iomem *addr;
	u32 reg;

	addr = bank_val_reg(gpio, bank, GPIO_DATA);
	reg = ioread32(addr);

	if (val)
		reg |= GPIO_BIT(offset);
	else
		reg &= ~GPIO_BIT(offset);

	iowrite32(reg, addr);
}

static void aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
			    int val)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
	unsigned long flags;

	spin_lock_irqsave(&gpio->lock, flags);

	__aspeed_gpio_set(gc, offset, val);

	spin_unlock_irqrestore(&gpio->lock, flags);
}

static int aspeed_gpio_dir_in(struct gpio_chip *gc, unsigned int offset)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
	const struct aspeed_gpio_bank *bank = to_bank(offset);
	unsigned long flags;
	u32 reg;

	if (!have_input(gpio, offset))
		return -ENOTSUPP;

	spin_lock_irqsave(&gpio->lock, flags);

	reg = ioread32(bank_val_reg(gpio, bank, GPIO_DIR));
	iowrite32(reg & ~GPIO_BIT(offset), bank_val_reg(gpio, bank, GPIO_DIR));

	spin_unlock_irqrestore(&gpio->lock, flags);

	return 0;
}

static int aspeed_gpio_dir_out(struct gpio_chip *gc,
			       unsigned int offset, int val)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
	const struct aspeed_gpio_bank *bank = to_bank(offset);
	unsigned long flags;
	u32 reg;

	if (!have_output(gpio, offset))
		return -ENOTSUPP;

	spin_lock_irqsave(&gpio->lock, flags);

	reg = ioread32(bank_val_reg(gpio, bank, GPIO_DIR));
	iowrite32(reg | GPIO_BIT(offset), bank_val_reg(gpio, bank, GPIO_DIR));

	__aspeed_gpio_set(gc, offset, val);

	spin_unlock_irqrestore(&gpio->lock, flags);

	return 0;
}

static int aspeed_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
	const struct aspeed_gpio_bank *bank = to_bank(offset);
	unsigned long flags;
	u32 val;

	if (!have_input(gpio, offset))
		return 0;

	if (!have_output(gpio, offset))
		return 1;

	spin_lock_irqsave(&gpio->lock, flags);

	val = ioread32(bank_val_reg(gpio, bank, GPIO_DIR)) & GPIO_BIT(offset);

	spin_unlock_irqrestore(&gpio->lock, flags);

	return !val;

}

static inline int irqd_to_aspeed_gpio_data(struct irq_data *d,
		struct aspeed_gpio **gpio,
		const struct aspeed_gpio_bank **bank,
		u32 *bit)
{
	int offset;
	struct aspeed_gpio *internal;

	offset = irqd_to_hwirq(d);

	internal = irq_data_get_irq_chip_data(d);

	/* This might be a bit of a questionable place to check */
	if (!have_irq(internal, offset))
		return -ENOTSUPP;

	*gpio = internal;
	*bank = to_bank(offset);
	*bit = GPIO_BIT(offset);

	return 0;
}

static void aspeed_gpio_irq_ack(struct irq_data *d)
{
	const struct aspeed_gpio_bank *bank;
	struct aspeed_gpio *gpio;
	unsigned long flags;
	void __iomem *status_addr;
	u32 bit;
	int rc;

	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit);
	if (rc)
		return;

	status_addr = bank_irq_reg(gpio, bank, GPIO_IRQ_STATUS);

	spin_lock_irqsave(&gpio->lock, flags);
	iowrite32(bit, status_addr);
	spin_unlock_irqrestore(&gpio->lock, flags);
}

static void aspeed_gpio_irq_set_mask(struct irq_data *d, bool set)
{
	const struct aspeed_gpio_bank *bank;
	struct aspeed_gpio *gpio;
	unsigned long flags;
	u32 reg, bit;
	void __iomem *addr;
	int rc;

	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit);
	if (rc)
		return;

	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_ENABLE);

	spin_lock_irqsave(&gpio->lock, flags);

	reg = ioread32(addr);
	if (set)
		reg |= bit;
	else
		reg &= bit;
	iowrite32(reg, addr);

	spin_unlock_irqrestore(&gpio->lock, flags);
}

static void aspeed_gpio_irq_mask(struct irq_data *d)
{
	aspeed_gpio_irq_set_mask(d, false);
}

static void aspeed_gpio_irq_unmask(struct irq_data *d)
{
	aspeed_gpio_irq_set_mask(d, true);
}

static int aspeed_gpio_set_type(struct irq_data *d, unsigned int type)
{
	u32 type0 = 0;
	u32 type1 = 0;
	u32 type2 = 0;
	u32 bit, reg;
	const struct aspeed_gpio_bank *bank;
	irq_flow_handler_t handler;
	struct aspeed_gpio *gpio;
	unsigned long flags;
	void __iomem *addr;
	int rc;

	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit);
	if (rc)
		return -EINVAL;

	switch (type & IRQ_TYPE_SENSE_MASK) {
	case IRQ_TYPE_EDGE_BOTH:
		type2 |= bit;
	case IRQ_TYPE_EDGE_RISING:
		type0 |= bit;
	case IRQ_TYPE_EDGE_FALLING:
		handler = handle_edge_irq;
		break;
	case IRQ_TYPE_LEVEL_HIGH:
		type0 |= bit;
	case IRQ_TYPE_LEVEL_LOW:
		type1 |= bit;
		handler = handle_level_irq;
		break;
	default:
		return -EINVAL;
	}

	spin_lock_irqsave(&gpio->lock, flags);

	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_TYPE0);
	reg = ioread32(addr);
	reg = (reg & ~bit) | type0;
	iowrite32(reg, addr);

	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_TYPE1);
	reg = ioread32(addr);
	reg = (reg & ~bit) | type1;
	iowrite32(reg, addr);

	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_TYPE2);
	reg = ioread32(addr);
	reg = (reg & ~bit) | type2;
	iowrite32(reg, addr);

	spin_unlock_irqrestore(&gpio->lock, flags);

	irq_set_handler_locked(d, handler);

	return 0;
}

static void aspeed_gpio_irq_handler(struct irq_desc *desc)
{
	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
	struct irq_chip *ic = irq_desc_get_chip(desc);
	struct aspeed_gpio *data = gpiochip_get_data(gc);
	unsigned int i, p, girq;
	unsigned long reg;

	chained_irq_enter(ic, desc);

	for (i = 0; i < ARRAY_SIZE(aspeed_gpio_banks); i++) {
		const struct aspeed_gpio_bank *bank = &aspeed_gpio_banks[i];

		reg = ioread32(bank_irq_reg(data, bank, GPIO_IRQ_STATUS));

		for_each_set_bit(p, &reg, 32) {
			girq = irq_find_mapping(gc->irqdomain, i * 32 + p);
			generic_handle_irq(girq);
		}

	}

	chained_irq_exit(ic, desc);
}

static struct irq_chip aspeed_gpio_irqchip = {
	.name		= "aspeed-gpio",
	.irq_ack	= aspeed_gpio_irq_ack,
	.irq_mask	= aspeed_gpio_irq_mask,
	.irq_unmask	= aspeed_gpio_irq_unmask,
	.irq_set_type	= aspeed_gpio_set_type,
};

static void set_irq_valid_mask(struct aspeed_gpio *gpio)
{
	const struct aspeed_bank_props *props = gpio->config->props;

	while (!is_bank_props_sentinel(props)) {
		unsigned int offset;
		const unsigned long int input = props->input;

		/* Pretty crummy approach, but similar to GPIO core */
		for_each_clear_bit(offset, &input, 32) {
			unsigned int i = props->bank * 32 + offset;

			if (i >= gpio->config->nr_gpios)
				break;

			clear_bit(i, gpio->chip.irq_valid_mask);
		}

		props++;
	}
}

static int aspeed_gpio_setup_irqs(struct aspeed_gpio *gpio,
		struct platform_device *pdev)
{
	int rc;

	rc = platform_get_irq(pdev, 0);
	if (rc < 0)
		return rc;

	gpio->irq = rc;

	set_irq_valid_mask(gpio);

	rc = gpiochip_irqchip_add(&gpio->chip, &aspeed_gpio_irqchip,
			0, handle_bad_irq, IRQ_TYPE_NONE);
	if (rc) {
		dev_info(&pdev->dev, "Could not add irqchip\n");
		return rc;
	}

	gpiochip_set_chained_irqchip(&gpio->chip, &aspeed_gpio_irqchip,
				     gpio->irq, aspeed_gpio_irq_handler);

	return 0;
}

static int aspeed_gpio_request(struct gpio_chip *chip, unsigned int offset)
{
	if (!have_gpio(gpiochip_get_data(chip), offset))
		return -ENODEV;

	return pinctrl_request_gpio(chip->base + offset);
}

static void aspeed_gpio_free(struct gpio_chip *chip, unsigned int offset)
{
	pinctrl_free_gpio(chip->base + offset);
}

static inline void __iomem *bank_debounce_reg(struct aspeed_gpio *gpio,
		const struct aspeed_gpio_bank *bank,
		unsigned int reg)
{
	return gpio->base + bank->debounce_regs + reg;
}

static int usecs_to_cycles(struct aspeed_gpio *gpio, unsigned long usecs,
		u32 *cycles)
{
	u64 rate;
	u64 n;
	u32 r;

	rate = clk_get_rate(gpio->clk);
	if (!rate)
		return -ENOTSUPP;

	n = rate * usecs;
	r = do_div(n, 1000000);

	if (n >= U32_MAX)
		return -ERANGE;

	/* At least as long as the requested time */
	*cycles = n + (!!r);

	return 0;
}

/* Call under gpio->lock */
static int register_allocated_timer(struct aspeed_gpio *gpio,
		unsigned int offset, unsigned int timer)
{
	if (WARN(gpio->offset_timer[offset] != 0,
				"Offset %d already allocated timer %d\n",
				offset, gpio->offset_timer[offset]))
		return -EINVAL;

	if (WARN(gpio->timer_users[timer] == UINT_MAX,
				"Timer user count would overflow\n"))
		return -EPERM;

	gpio->offset_timer[offset] = timer;
	gpio->timer_users[timer]++;

	return 0;
}

/* Call under gpio->lock */
static int unregister_allocated_timer(struct aspeed_gpio *gpio,
		unsigned int offset)
{
	if (WARN(gpio->offset_timer[offset] == 0,
				"No timer allocated to offset %d\n", offset))
		return -EINVAL;

	if (WARN(gpio->timer_users[gpio->offset_timer[offset]] == 0,
				"No users recorded for timer %d\n",
				gpio->offset_timer[offset]))
		return -EINVAL;

	gpio->timer_users[gpio->offset_timer[offset]]--;
	gpio->offset_timer[offset] = 0;

	return 0;
}

/* Call under gpio->lock */
static inline bool timer_allocation_registered(struct aspeed_gpio *gpio,
		unsigned int offset)
{
	return gpio->offset_timer[offset] > 0;
}

/* Call under gpio->lock */
static void configure_timer(struct aspeed_gpio *gpio, unsigned int offset,
		unsigned int timer)
{
	const struct aspeed_gpio_bank *bank = to_bank(offset);
	const u32 mask = GPIO_BIT(offset);
	void __iomem *addr;
	u32 val;

	addr = bank_debounce_reg(gpio, bank, GPIO_DEBOUNCE_SEL1);
	val = ioread32(addr);
	iowrite32((val & ~mask) | GPIO_SET_DEBOUNCE1(timer, offset), addr);

	addr = bank_debounce_reg(gpio, bank, GPIO_DEBOUNCE_SEL2);
	val = ioread32(addr);
	iowrite32((val & ~mask) | GPIO_SET_DEBOUNCE2(timer, offset), addr);
}

static int enable_debounce(struct gpio_chip *chip, unsigned int offset,
				    unsigned long usecs)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
	u32 requested_cycles;
	unsigned long flags;
	int rc;
	int i;

	rc = usecs_to_cycles(gpio, usecs, &requested_cycles);
	if (rc < 0) {
		dev_warn(chip->parent, "Failed to convert %luus to cycles at %luHz: %d\n",
				usecs, clk_get_rate(gpio->clk), rc);
		return rc;
	}

	spin_lock_irqsave(&gpio->lock, flags);

	if (timer_allocation_registered(gpio, offset)) {
		rc = unregister_allocated_timer(gpio, offset);
		if (rc < 0)
			goto out;
	}

	/* Try to find a timer already configured for the debounce period */
	for (i = 1; i < ARRAY_SIZE(debounce_timers); i++) {
		u32 cycles;

		cycles = ioread32(gpio->base + debounce_timers[i]);
		if (requested_cycles == cycles)
			break;
	}

	if (i == ARRAY_SIZE(debounce_timers)) {
		int j;

		/*
		 * As there are no timers configured for the requested debounce
		 * period, find an unused timer instead
		 */
		for (j = 1; j < ARRAY_SIZE(gpio->timer_users); j++) {
			if (gpio->timer_users[j] == 0)
				break;
		}

		if (j == ARRAY_SIZE(gpio->timer_users)) {
			dev_warn(chip->parent,
					"Debounce timers exhausted, cannot debounce for period %luus\n",
					usecs);

			rc = -EPERM;

			/*
			 * We already adjusted the accounting to remove @offset
			 * as a user of its previous timer, so also configure
			 * the hardware so @offset has timers disabled for
			 * consistency.
			 */
			configure_timer(gpio, offset, 0);
			goto out;
		}

		i = j;

		iowrite32(requested_cycles, gpio->base + debounce_timers[i]);
	}

	if (WARN(i == 0, "Cannot register index of disabled timer\n")) {
		rc = -EINVAL;
		goto out;
	}

	register_allocated_timer(gpio, offset, i);
	configure_timer(gpio, offset, i);

out:
	spin_unlock_irqrestore(&gpio->lock, flags);

	return rc;
}

static int disable_debounce(struct gpio_chip *chip, unsigned int offset)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
	unsigned long flags;
	int rc;

	spin_lock_irqsave(&gpio->lock, flags);

	rc = unregister_allocated_timer(gpio, offset);
	if (!rc)
		configure_timer(gpio, offset, 0);

	spin_unlock_irqrestore(&gpio->lock, flags);

	return rc;
}

static int set_debounce(struct gpio_chip *chip, unsigned int offset,
				    unsigned long usecs)
{
	struct aspeed_gpio *gpio = gpiochip_get_data(chip);

	if (!have_debounce(gpio, offset))
		return -ENOTSUPP;

	if (usecs)
		return enable_debounce(chip, offset, usecs);

	return disable_debounce(chip, offset);
}

static int aspeed_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
				  unsigned long config)
{
	unsigned long param = pinconf_to_config_param(config);
	u32 arg = pinconf_to_config_argument(config);

	if (param == PIN_CONFIG_INPUT_DEBOUNCE)
		return set_debounce(chip, offset, arg);
	else if (param == PIN_CONFIG_BIAS_DISABLE ||
			param == PIN_CONFIG_BIAS_PULL_DOWN ||
			param == PIN_CONFIG_DRIVE_STRENGTH)
		return pinctrl_gpio_set_config(offset, config);
	else if (param == PIN_CONFIG_DRIVE_OPEN_DRAIN ||
			param == PIN_CONFIG_DRIVE_OPEN_SOURCE)
		/* Return -ENOTSUPP to trigger emulation, as per datasheet */
		return -ENOTSUPP;

	return -ENOTSUPP;
}

/*
 * Any banks not specified in a struct aspeed_bank_props array are assumed to
 * have the properties:
 *
 *     { .input = 0xffffffff, .output = 0xffffffff }
 */

static const struct aspeed_bank_props ast2400_bank_props[] = {
	/*     input	  output   */
	{ 5, 0xffffffff, 0x0000ffff }, /* U/V/W/X */
	{ 6, 0x0000000f, 0x0fffff0f }, /* Y/Z/AA/AB, two 4-GPIO holes */
	{ },
};

static const struct aspeed_gpio_config ast2400_config =
	/* 220 for simplicity, really 216 with two 4-GPIO holes, four at end */
	{ .nr_gpios = 220, .props = ast2400_bank_props, };

static const struct aspeed_bank_props ast2500_bank_props[] = {
	/*     input	  output   */
	{ 5, 0xffffffff, 0x0000ffff }, /* U/V/W/X */
	{ 6, 0x0fffffff, 0x0fffffff }, /* Y/Z/AA/AB, 4-GPIO hole */
	{ 7, 0x000000ff, 0x000000ff }, /* AC */
	{ },
};

static const struct aspeed_gpio_config ast2500_config =
	/* 232 for simplicity, actual number is 228 (4-GPIO hole in GPIOAB) */
	{ .nr_gpios = 232, .props = ast2500_bank_props, };

static const struct of_device_id aspeed_gpio_of_table[] = {
	{ .compatible = "aspeed,ast2400-gpio", .data = &ast2400_config, },
	{ .compatible = "aspeed,ast2500-gpio", .data = &ast2500_config, },
	{}
};
MODULE_DEVICE_TABLE(of, aspeed_gpio_of_table);

static int __init aspeed_gpio_probe(struct platform_device *pdev)
{
	const struct of_device_id *gpio_id;
	struct aspeed_gpio *gpio;
	struct resource *res;
	int rc;

	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
	if (!gpio)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	gpio->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(gpio->base))
		return PTR_ERR(gpio->base);

	spin_lock_init(&gpio->lock);

	gpio_id = of_match_node(aspeed_gpio_of_table, pdev->dev.of_node);
	if (!gpio_id)
		return -EINVAL;

	gpio->clk = of_clk_get(pdev->dev.of_node, 0);
	if (IS_ERR(gpio->clk)) {
		dev_warn(&pdev->dev,
				"No HPLL clock phandle provided, debouncing disabled\n");
		gpio->clk = NULL;
	}

	gpio->config = gpio_id->data;

	gpio->chip.parent = &pdev->dev;
	gpio->chip.ngpio = gpio->config->nr_gpios;
	gpio->chip.parent = &pdev->dev;
	gpio->chip.direction_input = aspeed_gpio_dir_in;
	gpio->chip.direction_output = aspeed_gpio_dir_out;
	gpio->chip.get_direction = aspeed_gpio_get_direction;
	gpio->chip.request = aspeed_gpio_request;
	gpio->chip.free = aspeed_gpio_free;
	gpio->chip.get = aspeed_gpio_get;
	gpio->chip.set = aspeed_gpio_set;
	gpio->chip.set_config = aspeed_gpio_set_config;
	gpio->chip.label = dev_name(&pdev->dev);
	gpio->chip.base = -1;
	gpio->chip.irq_need_valid_mask = true;

	rc = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
	if (rc < 0)
		return rc;

	gpio->offset_timer =
		devm_kzalloc(&pdev->dev, gpio->chip.ngpio, GFP_KERNEL);

	return aspeed_gpio_setup_irqs(gpio, pdev);
}

static struct platform_driver aspeed_gpio_driver = {
	.driver = {
		.name = KBUILD_MODNAME,
		.of_match_table = aspeed_gpio_of_table,
	},
};

module_platform_driver_probe(aspeed_gpio_driver, aspeed_gpio_probe);

MODULE_DESCRIPTION("Aspeed GPIO Driver");
MODULE_LICENSE("GPL");