xref: /openbmc/linux/drivers/gpio/gpio-aspeed.c (revision 7aacf86b)
1 /*
2  * Copyright 2015 IBM Corp.
3  *
4  * Joel Stanley <joel@jms.id.au>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * as published by the Free Software Foundation; either version
9  * 2 of the License, or (at your option) any later version.
10  */
11 
12 #include <asm/div64.h>
13 #include <linux/clk.h>
14 #include <linux/gpio/driver.h>
15 #include <linux/hashtable.h>
16 #include <linux/init.h>
17 #include <linux/io.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/pinctrl/consumer.h>
21 #include <linux/platform_device.h>
22 #include <linux/spinlock.h>
23 #include <linux/string.h>
24 
25 struct aspeed_bank_props {
26 	unsigned int bank;
27 	u32 input;
28 	u32 output;
29 };
30 
31 struct aspeed_gpio_config {
32 	unsigned int nr_gpios;
33 	const struct aspeed_bank_props *props;
34 };
35 
36 /*
37  * @offset_timer: Maps an offset to an @timer_users index, or zero if disabled
38  * @timer_users: Tracks the number of users for each timer
39  *
40  * The @timer_users has four elements but the first element is unused. This is
41  * to simplify accounting and indexing, as a zero value in @offset_timer
42  * represents disabled debouncing for the GPIO. Any other value for an element
43  * of @offset_timer is used as an index into @timer_users. This behaviour of
44  * the zero value aligns with the behaviour of zero built from the timer
45  * configuration registers (i.e. debouncing is disabled).
46  */
47 struct aspeed_gpio {
48 	struct gpio_chip chip;
49 	spinlock_t lock;
50 	void __iomem *base;
51 	int irq;
52 	const struct aspeed_gpio_config *config;
53 
54 	u8 *offset_timer;
55 	unsigned int timer_users[4];
56 	struct clk *clk;
57 };
58 
59 struct aspeed_gpio_bank {
60 	uint16_t	val_regs;
61 	uint16_t	irq_regs;
62 	uint16_t	debounce_regs;
63 	const char	names[4][3];
64 };
65 
66 static const int debounce_timers[4] = { 0x00, 0x50, 0x54, 0x58 };
67 
68 static const struct aspeed_gpio_bank aspeed_gpio_banks[] = {
69 	{
70 		.val_regs = 0x0000,
71 		.irq_regs = 0x0008,
72 		.debounce_regs = 0x0040,
73 		.names = { "A", "B", "C", "D" },
74 	},
75 	{
76 		.val_regs = 0x0020,
77 		.irq_regs = 0x0028,
78 		.debounce_regs = 0x0048,
79 		.names = { "E", "F", "G", "H" },
80 	},
81 	{
82 		.val_regs = 0x0070,
83 		.irq_regs = 0x0098,
84 		.debounce_regs = 0x00b0,
85 		.names = { "I", "J", "K", "L" },
86 	},
87 	{
88 		.val_regs = 0x0078,
89 		.irq_regs = 0x00e8,
90 		.debounce_regs = 0x0100,
91 		.names = { "M", "N", "O", "P" },
92 	},
93 	{
94 		.val_regs = 0x0080,
95 		.irq_regs = 0x0118,
96 		.debounce_regs = 0x0130,
97 		.names = { "Q", "R", "S", "T" },
98 	},
99 	{
100 		.val_regs = 0x0088,
101 		.irq_regs = 0x0148,
102 		.debounce_regs = 0x0160,
103 		.names = { "U", "V", "W", "X" },
104 	},
105 	{
106 		.val_regs = 0x01E0,
107 		.irq_regs = 0x0178,
108 		.debounce_regs = 0x0190,
109 		.names = { "Y", "Z", "AA", "AB" },
110 	},
111 	{
112 		.val_regs = 0x01E8,
113 		.irq_regs = 0x01A8,
114 		.debounce_regs = 0x01c0,
115 		.names = { "AC", "", "", "" },
116 	},
117 };
118 
119 #define GPIO_BANK(x)	((x) >> 5)
120 #define GPIO_OFFSET(x)	((x) & 0x1f)
121 #define GPIO_BIT(x)	BIT(GPIO_OFFSET(x))
122 
123 #define GPIO_DATA	0x00
124 #define GPIO_DIR	0x04
125 
126 #define GPIO_IRQ_ENABLE	0x00
127 #define GPIO_IRQ_TYPE0	0x04
128 #define GPIO_IRQ_TYPE1	0x08
129 #define GPIO_IRQ_TYPE2	0x0c
130 #define GPIO_IRQ_STATUS	0x10
131 
132 #define GPIO_DEBOUNCE_SEL1 0x00
133 #define GPIO_DEBOUNCE_SEL2 0x04
134 
135 #define _GPIO_SET_DEBOUNCE(t, o, i) ((!!((t) & BIT(i))) << GPIO_OFFSET(o))
136 #define GPIO_SET_DEBOUNCE1(t, o) _GPIO_SET_DEBOUNCE(t, o, 1)
137 #define GPIO_SET_DEBOUNCE2(t, o) _GPIO_SET_DEBOUNCE(t, o, 0)
138 
139 static const struct aspeed_gpio_bank *to_bank(unsigned int offset)
140 {
141 	unsigned int bank = GPIO_BANK(offset);
142 
143 	WARN_ON(bank > ARRAY_SIZE(aspeed_gpio_banks));
144 	return &aspeed_gpio_banks[bank];
145 }
146 
147 static inline bool is_bank_props_sentinel(const struct aspeed_bank_props *props)
148 {
149 	return !(props->input || props->output);
150 }
151 
152 static inline const struct aspeed_bank_props *find_bank_props(
153 		struct aspeed_gpio *gpio, unsigned int offset)
154 {
155 	const struct aspeed_bank_props *props = gpio->config->props;
156 
157 	while (!is_bank_props_sentinel(props)) {
158 		if (props->bank == GPIO_BANK(offset))
159 			return props;
160 		props++;
161 	}
162 
163 	return NULL;
164 }
165 
166 static inline bool have_gpio(struct aspeed_gpio *gpio, unsigned int offset)
167 {
168 	const struct aspeed_bank_props *props = find_bank_props(gpio, offset);
169 	const struct aspeed_gpio_bank *bank = to_bank(offset);
170 	unsigned int group = GPIO_OFFSET(offset) / 8;
171 
172 	return bank->names[group][0] != '\0' &&
173 		(!props || ((props->input | props->output) & GPIO_BIT(offset)));
174 }
175 
176 static inline bool have_input(struct aspeed_gpio *gpio, unsigned int offset)
177 {
178 	const struct aspeed_bank_props *props = find_bank_props(gpio, offset);
179 
180 	return !props || (props->input & GPIO_BIT(offset));
181 }
182 
183 #define have_irq(g, o) have_input((g), (o))
184 #define have_debounce(g, o) have_input((g), (o))
185 
186 static inline bool have_output(struct aspeed_gpio *gpio, unsigned int offset)
187 {
188 	const struct aspeed_bank_props *props = find_bank_props(gpio, offset);
189 
190 	return !props || (props->output & GPIO_BIT(offset));
191 }
192 
193 static void __iomem *bank_val_reg(struct aspeed_gpio *gpio,
194 		const struct aspeed_gpio_bank *bank,
195 		unsigned int reg)
196 {
197 	return gpio->base + bank->val_regs + reg;
198 }
199 
200 static void __iomem *bank_irq_reg(struct aspeed_gpio *gpio,
201 		const struct aspeed_gpio_bank *bank,
202 		unsigned int reg)
203 {
204 	return gpio->base + bank->irq_regs + reg;
205 }
206 
207 static int aspeed_gpio_get(struct gpio_chip *gc, unsigned int offset)
208 {
209 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
210 	const struct aspeed_gpio_bank *bank = to_bank(offset);
211 
212 	return !!(ioread32(bank_val_reg(gpio, bank, GPIO_DATA))
213 			& GPIO_BIT(offset));
214 }
215 
216 static void __aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
217 			      int val)
218 {
219 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
220 	const struct aspeed_gpio_bank *bank = to_bank(offset);
221 	void __iomem *addr;
222 	u32 reg;
223 
224 	addr = bank_val_reg(gpio, bank, GPIO_DATA);
225 	reg = ioread32(addr);
226 
227 	if (val)
228 		reg |= GPIO_BIT(offset);
229 	else
230 		reg &= ~GPIO_BIT(offset);
231 
232 	iowrite32(reg, addr);
233 }
234 
235 static void aspeed_gpio_set(struct gpio_chip *gc, unsigned int offset,
236 			    int val)
237 {
238 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
239 	unsigned long flags;
240 
241 	spin_lock_irqsave(&gpio->lock, flags);
242 
243 	__aspeed_gpio_set(gc, offset, val);
244 
245 	spin_unlock_irqrestore(&gpio->lock, flags);
246 }
247 
248 static int aspeed_gpio_dir_in(struct gpio_chip *gc, unsigned int offset)
249 {
250 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
251 	const struct aspeed_gpio_bank *bank = to_bank(offset);
252 	unsigned long flags;
253 	u32 reg;
254 
255 	if (!have_input(gpio, offset))
256 		return -ENOTSUPP;
257 
258 	spin_lock_irqsave(&gpio->lock, flags);
259 
260 	reg = ioread32(bank_val_reg(gpio, bank, GPIO_DIR));
261 	iowrite32(reg & ~GPIO_BIT(offset), bank_val_reg(gpio, bank, GPIO_DIR));
262 
263 	spin_unlock_irqrestore(&gpio->lock, flags);
264 
265 	return 0;
266 }
267 
268 static int aspeed_gpio_dir_out(struct gpio_chip *gc,
269 			       unsigned int offset, int val)
270 {
271 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
272 	const struct aspeed_gpio_bank *bank = to_bank(offset);
273 	unsigned long flags;
274 	u32 reg;
275 
276 	if (!have_output(gpio, offset))
277 		return -ENOTSUPP;
278 
279 	spin_lock_irqsave(&gpio->lock, flags);
280 
281 	reg = ioread32(bank_val_reg(gpio, bank, GPIO_DIR));
282 	iowrite32(reg | GPIO_BIT(offset), bank_val_reg(gpio, bank, GPIO_DIR));
283 
284 	__aspeed_gpio_set(gc, offset, val);
285 
286 	spin_unlock_irqrestore(&gpio->lock, flags);
287 
288 	return 0;
289 }
290 
291 static int aspeed_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
292 {
293 	struct aspeed_gpio *gpio = gpiochip_get_data(gc);
294 	const struct aspeed_gpio_bank *bank = to_bank(offset);
295 	unsigned long flags;
296 	u32 val;
297 
298 	if (!have_input(gpio, offset))
299 		return 0;
300 
301 	if (!have_output(gpio, offset))
302 		return 1;
303 
304 	spin_lock_irqsave(&gpio->lock, flags);
305 
306 	val = ioread32(bank_val_reg(gpio, bank, GPIO_DIR)) & GPIO_BIT(offset);
307 
308 	spin_unlock_irqrestore(&gpio->lock, flags);
309 
310 	return !val;
311 
312 }
313 
314 static inline int irqd_to_aspeed_gpio_data(struct irq_data *d,
315 		struct aspeed_gpio **gpio,
316 		const struct aspeed_gpio_bank **bank,
317 		u32 *bit)
318 {
319 	int offset;
320 	struct aspeed_gpio *internal;
321 
322 	offset = irqd_to_hwirq(d);
323 
324 	internal = irq_data_get_irq_chip_data(d);
325 
326 	/* This might be a bit of a questionable place to check */
327 	if (!have_irq(internal, offset))
328 		return -ENOTSUPP;
329 
330 	*gpio = internal;
331 	*bank = to_bank(offset);
332 	*bit = GPIO_BIT(offset);
333 
334 	return 0;
335 }
336 
337 static void aspeed_gpio_irq_ack(struct irq_data *d)
338 {
339 	const struct aspeed_gpio_bank *bank;
340 	struct aspeed_gpio *gpio;
341 	unsigned long flags;
342 	void __iomem *status_addr;
343 	u32 bit;
344 	int rc;
345 
346 	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit);
347 	if (rc)
348 		return;
349 
350 	status_addr = bank_irq_reg(gpio, bank, GPIO_IRQ_STATUS);
351 
352 	spin_lock_irqsave(&gpio->lock, flags);
353 	iowrite32(bit, status_addr);
354 	spin_unlock_irqrestore(&gpio->lock, flags);
355 }
356 
357 static void aspeed_gpio_irq_set_mask(struct irq_data *d, bool set)
358 {
359 	const struct aspeed_gpio_bank *bank;
360 	struct aspeed_gpio *gpio;
361 	unsigned long flags;
362 	u32 reg, bit;
363 	void __iomem *addr;
364 	int rc;
365 
366 	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit);
367 	if (rc)
368 		return;
369 
370 	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_ENABLE);
371 
372 	spin_lock_irqsave(&gpio->lock, flags);
373 
374 	reg = ioread32(addr);
375 	if (set)
376 		reg |= bit;
377 	else
378 		reg &= bit;
379 	iowrite32(reg, addr);
380 
381 	spin_unlock_irqrestore(&gpio->lock, flags);
382 }
383 
384 static void aspeed_gpio_irq_mask(struct irq_data *d)
385 {
386 	aspeed_gpio_irq_set_mask(d, false);
387 }
388 
389 static void aspeed_gpio_irq_unmask(struct irq_data *d)
390 {
391 	aspeed_gpio_irq_set_mask(d, true);
392 }
393 
394 static int aspeed_gpio_set_type(struct irq_data *d, unsigned int type)
395 {
396 	u32 type0 = 0;
397 	u32 type1 = 0;
398 	u32 type2 = 0;
399 	u32 bit, reg;
400 	const struct aspeed_gpio_bank *bank;
401 	irq_flow_handler_t handler;
402 	struct aspeed_gpio *gpio;
403 	unsigned long flags;
404 	void __iomem *addr;
405 	int rc;
406 
407 	rc = irqd_to_aspeed_gpio_data(d, &gpio, &bank, &bit);
408 	if (rc)
409 		return -EINVAL;
410 
411 	switch (type & IRQ_TYPE_SENSE_MASK) {
412 	case IRQ_TYPE_EDGE_BOTH:
413 		type2 |= bit;
414 	case IRQ_TYPE_EDGE_RISING:
415 		type0 |= bit;
416 	case IRQ_TYPE_EDGE_FALLING:
417 		handler = handle_edge_irq;
418 		break;
419 	case IRQ_TYPE_LEVEL_HIGH:
420 		type0 |= bit;
421 	case IRQ_TYPE_LEVEL_LOW:
422 		type1 |= bit;
423 		handler = handle_level_irq;
424 		break;
425 	default:
426 		return -EINVAL;
427 	}
428 
429 	spin_lock_irqsave(&gpio->lock, flags);
430 
431 	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_TYPE0);
432 	reg = ioread32(addr);
433 	reg = (reg & ~bit) | type0;
434 	iowrite32(reg, addr);
435 
436 	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_TYPE1);
437 	reg = ioread32(addr);
438 	reg = (reg & ~bit) | type1;
439 	iowrite32(reg, addr);
440 
441 	addr = bank_irq_reg(gpio, bank, GPIO_IRQ_TYPE2);
442 	reg = ioread32(addr);
443 	reg = (reg & ~bit) | type2;
444 	iowrite32(reg, addr);
445 
446 	spin_unlock_irqrestore(&gpio->lock, flags);
447 
448 	irq_set_handler_locked(d, handler);
449 
450 	return 0;
451 }
452 
453 static void aspeed_gpio_irq_handler(struct irq_desc *desc)
454 {
455 	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
456 	struct irq_chip *ic = irq_desc_get_chip(desc);
457 	struct aspeed_gpio *data = gpiochip_get_data(gc);
458 	unsigned int i, p, girq;
459 	unsigned long reg;
460 
461 	chained_irq_enter(ic, desc);
462 
463 	for (i = 0; i < ARRAY_SIZE(aspeed_gpio_banks); i++) {
464 		const struct aspeed_gpio_bank *bank = &aspeed_gpio_banks[i];
465 
466 		reg = ioread32(bank_irq_reg(data, bank, GPIO_IRQ_STATUS));
467 
468 		for_each_set_bit(p, &reg, 32) {
469 			girq = irq_find_mapping(gc->irqdomain, i * 32 + p);
470 			generic_handle_irq(girq);
471 		}
472 
473 	}
474 
475 	chained_irq_exit(ic, desc);
476 }
477 
478 static struct irq_chip aspeed_gpio_irqchip = {
479 	.name		= "aspeed-gpio",
480 	.irq_ack	= aspeed_gpio_irq_ack,
481 	.irq_mask	= aspeed_gpio_irq_mask,
482 	.irq_unmask	= aspeed_gpio_irq_unmask,
483 	.irq_set_type	= aspeed_gpio_set_type,
484 };
485 
486 static void set_irq_valid_mask(struct aspeed_gpio *gpio)
487 {
488 	const struct aspeed_bank_props *props = gpio->config->props;
489 
490 	while (!is_bank_props_sentinel(props)) {
491 		unsigned int offset;
492 		const unsigned long int input = props->input;
493 
494 		/* Pretty crummy approach, but similar to GPIO core */
495 		for_each_clear_bit(offset, &input, 32) {
496 			unsigned int i = props->bank * 32 + offset;
497 
498 			if (i >= gpio->config->nr_gpios)
499 				break;
500 
501 			clear_bit(i, gpio->chip.irq_valid_mask);
502 		}
503 
504 		props++;
505 	}
506 }
507 
508 static int aspeed_gpio_setup_irqs(struct aspeed_gpio *gpio,
509 		struct platform_device *pdev)
510 {
511 	int rc;
512 
513 	rc = platform_get_irq(pdev, 0);
514 	if (rc < 0)
515 		return rc;
516 
517 	gpio->irq = rc;
518 
519 	set_irq_valid_mask(gpio);
520 
521 	rc = gpiochip_irqchip_add(&gpio->chip, &aspeed_gpio_irqchip,
522 			0, handle_bad_irq, IRQ_TYPE_NONE);
523 	if (rc) {
524 		dev_info(&pdev->dev, "Could not add irqchip\n");
525 		return rc;
526 	}
527 
528 	gpiochip_set_chained_irqchip(&gpio->chip, &aspeed_gpio_irqchip,
529 				     gpio->irq, aspeed_gpio_irq_handler);
530 
531 	return 0;
532 }
533 
534 static int aspeed_gpio_request(struct gpio_chip *chip, unsigned int offset)
535 {
536 	if (!have_gpio(gpiochip_get_data(chip), offset))
537 		return -ENODEV;
538 
539 	return pinctrl_request_gpio(chip->base + offset);
540 }
541 
542 static void aspeed_gpio_free(struct gpio_chip *chip, unsigned int offset)
543 {
544 	pinctrl_free_gpio(chip->base + offset);
545 }
546 
547 static inline void __iomem *bank_debounce_reg(struct aspeed_gpio *gpio,
548 		const struct aspeed_gpio_bank *bank,
549 		unsigned int reg)
550 {
551 	return gpio->base + bank->debounce_regs + reg;
552 }
553 
554 static int usecs_to_cycles(struct aspeed_gpio *gpio, unsigned long usecs,
555 		u32 *cycles)
556 {
557 	u64 rate;
558 	u64 n;
559 	u32 r;
560 
561 	rate = clk_get_rate(gpio->clk);
562 	if (!rate)
563 		return -ENOTSUPP;
564 
565 	n = rate * usecs;
566 	r = do_div(n, 1000000);
567 
568 	if (n >= U32_MAX)
569 		return -ERANGE;
570 
571 	/* At least as long as the requested time */
572 	*cycles = n + (!!r);
573 
574 	return 0;
575 }
576 
577 /* Call under gpio->lock */
578 static int register_allocated_timer(struct aspeed_gpio *gpio,
579 		unsigned int offset, unsigned int timer)
580 {
581 	if (WARN(gpio->offset_timer[offset] != 0,
582 				"Offset %d already allocated timer %d\n",
583 				offset, gpio->offset_timer[offset]))
584 		return -EINVAL;
585 
586 	if (WARN(gpio->timer_users[timer] == UINT_MAX,
587 				"Timer user count would overflow\n"))
588 		return -EPERM;
589 
590 	gpio->offset_timer[offset] = timer;
591 	gpio->timer_users[timer]++;
592 
593 	return 0;
594 }
595 
596 /* Call under gpio->lock */
597 static int unregister_allocated_timer(struct aspeed_gpio *gpio,
598 		unsigned int offset)
599 {
600 	if (WARN(gpio->offset_timer[offset] == 0,
601 				"No timer allocated to offset %d\n", offset))
602 		return -EINVAL;
603 
604 	if (WARN(gpio->timer_users[gpio->offset_timer[offset]] == 0,
605 				"No users recorded for timer %d\n",
606 				gpio->offset_timer[offset]))
607 		return -EINVAL;
608 
609 	gpio->timer_users[gpio->offset_timer[offset]]--;
610 	gpio->offset_timer[offset] = 0;
611 
612 	return 0;
613 }
614 
615 /* Call under gpio->lock */
616 static inline bool timer_allocation_registered(struct aspeed_gpio *gpio,
617 		unsigned int offset)
618 {
619 	return gpio->offset_timer[offset] > 0;
620 }
621 
622 /* Call under gpio->lock */
623 static void configure_timer(struct aspeed_gpio *gpio, unsigned int offset,
624 		unsigned int timer)
625 {
626 	const struct aspeed_gpio_bank *bank = to_bank(offset);
627 	const u32 mask = GPIO_BIT(offset);
628 	void __iomem *addr;
629 	u32 val;
630 
631 	addr = bank_debounce_reg(gpio, bank, GPIO_DEBOUNCE_SEL1);
632 	val = ioread32(addr);
633 	iowrite32((val & ~mask) | GPIO_SET_DEBOUNCE1(timer, offset), addr);
634 
635 	addr = bank_debounce_reg(gpio, bank, GPIO_DEBOUNCE_SEL2);
636 	val = ioread32(addr);
637 	iowrite32((val & ~mask) | GPIO_SET_DEBOUNCE2(timer, offset), addr);
638 }
639 
640 static int enable_debounce(struct gpio_chip *chip, unsigned int offset,
641 				    unsigned long usecs)
642 {
643 	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
644 	u32 requested_cycles;
645 	unsigned long flags;
646 	int rc;
647 	int i;
648 
649 	if (!gpio->clk)
650 		return -EINVAL;
651 
652 	rc = usecs_to_cycles(gpio, usecs, &requested_cycles);
653 	if (rc < 0) {
654 		dev_warn(chip->parent, "Failed to convert %luus to cycles at %luHz: %d\n",
655 				usecs, clk_get_rate(gpio->clk), rc);
656 		return rc;
657 	}
658 
659 	spin_lock_irqsave(&gpio->lock, flags);
660 
661 	if (timer_allocation_registered(gpio, offset)) {
662 		rc = unregister_allocated_timer(gpio, offset);
663 		if (rc < 0)
664 			goto out;
665 	}
666 
667 	/* Try to find a timer already configured for the debounce period */
668 	for (i = 1; i < ARRAY_SIZE(debounce_timers); i++) {
669 		u32 cycles;
670 
671 		cycles = ioread32(gpio->base + debounce_timers[i]);
672 		if (requested_cycles == cycles)
673 			break;
674 	}
675 
676 	if (i == ARRAY_SIZE(debounce_timers)) {
677 		int j;
678 
679 		/*
680 		 * As there are no timers configured for the requested debounce
681 		 * period, find an unused timer instead
682 		 */
683 		for (j = 1; j < ARRAY_SIZE(gpio->timer_users); j++) {
684 			if (gpio->timer_users[j] == 0)
685 				break;
686 		}
687 
688 		if (j == ARRAY_SIZE(gpio->timer_users)) {
689 			dev_warn(chip->parent,
690 					"Debounce timers exhausted, cannot debounce for period %luus\n",
691 					usecs);
692 
693 			rc = -EPERM;
694 
695 			/*
696 			 * We already adjusted the accounting to remove @offset
697 			 * as a user of its previous timer, so also configure
698 			 * the hardware so @offset has timers disabled for
699 			 * consistency.
700 			 */
701 			configure_timer(gpio, offset, 0);
702 			goto out;
703 		}
704 
705 		i = j;
706 
707 		iowrite32(requested_cycles, gpio->base + debounce_timers[i]);
708 	}
709 
710 	if (WARN(i == 0, "Cannot register index of disabled timer\n")) {
711 		rc = -EINVAL;
712 		goto out;
713 	}
714 
715 	register_allocated_timer(gpio, offset, i);
716 	configure_timer(gpio, offset, i);
717 
718 out:
719 	spin_unlock_irqrestore(&gpio->lock, flags);
720 
721 	return rc;
722 }
723 
724 static int disable_debounce(struct gpio_chip *chip, unsigned int offset)
725 {
726 	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
727 	unsigned long flags;
728 	int rc;
729 
730 	spin_lock_irqsave(&gpio->lock, flags);
731 
732 	rc = unregister_allocated_timer(gpio, offset);
733 	if (!rc)
734 		configure_timer(gpio, offset, 0);
735 
736 	spin_unlock_irqrestore(&gpio->lock, flags);
737 
738 	return rc;
739 }
740 
741 static int set_debounce(struct gpio_chip *chip, unsigned int offset,
742 				    unsigned long usecs)
743 {
744 	struct aspeed_gpio *gpio = gpiochip_get_data(chip);
745 
746 	if (!have_debounce(gpio, offset))
747 		return -ENOTSUPP;
748 
749 	if (usecs)
750 		return enable_debounce(chip, offset, usecs);
751 
752 	return disable_debounce(chip, offset);
753 }
754 
755 static int aspeed_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
756 				  unsigned long config)
757 {
758 	unsigned long param = pinconf_to_config_param(config);
759 	u32 arg = pinconf_to_config_argument(config);
760 
761 	if (param == PIN_CONFIG_INPUT_DEBOUNCE)
762 		return set_debounce(chip, offset, arg);
763 	else if (param == PIN_CONFIG_BIAS_DISABLE ||
764 			param == PIN_CONFIG_BIAS_PULL_DOWN ||
765 			param == PIN_CONFIG_DRIVE_STRENGTH)
766 		return pinctrl_gpio_set_config(offset, config);
767 	else if (param == PIN_CONFIG_DRIVE_OPEN_DRAIN ||
768 			param == PIN_CONFIG_DRIVE_OPEN_SOURCE)
769 		/* Return -ENOTSUPP to trigger emulation, as per datasheet */
770 		return -ENOTSUPP;
771 
772 	return -ENOTSUPP;
773 }
774 
775 /*
776  * Any banks not specified in a struct aspeed_bank_props array are assumed to
777  * have the properties:
778  *
779  *     { .input = 0xffffffff, .output = 0xffffffff }
780  */
781 
782 static const struct aspeed_bank_props ast2400_bank_props[] = {
783 	/*     input	  output   */
784 	{ 5, 0xffffffff, 0x0000ffff }, /* U/V/W/X */
785 	{ 6, 0x0000000f, 0x0fffff0f }, /* Y/Z/AA/AB, two 4-GPIO holes */
786 	{ },
787 };
788 
789 static const struct aspeed_gpio_config ast2400_config =
790 	/* 220 for simplicity, really 216 with two 4-GPIO holes, four at end */
791 	{ .nr_gpios = 220, .props = ast2400_bank_props, };
792 
793 static const struct aspeed_bank_props ast2500_bank_props[] = {
794 	/*     input	  output   */
795 	{ 5, 0xffffffff, 0x0000ffff }, /* U/V/W/X */
796 	{ 6, 0x0fffffff, 0x0fffffff }, /* Y/Z/AA/AB, 4-GPIO hole */
797 	{ 7, 0x000000ff, 0x000000ff }, /* AC */
798 	{ },
799 };
800 
801 static const struct aspeed_gpio_config ast2500_config =
802 	/* 232 for simplicity, actual number is 228 (4-GPIO hole in GPIOAB) */
803 	{ .nr_gpios = 232, .props = ast2500_bank_props, };
804 
805 static const struct of_device_id aspeed_gpio_of_table[] = {
806 	{ .compatible = "aspeed,ast2400-gpio", .data = &ast2400_config, },
807 	{ .compatible = "aspeed,ast2500-gpio", .data = &ast2500_config, },
808 	{}
809 };
810 MODULE_DEVICE_TABLE(of, aspeed_gpio_of_table);
811 
812 static int __init aspeed_gpio_probe(struct platform_device *pdev)
813 {
814 	const struct of_device_id *gpio_id;
815 	struct aspeed_gpio *gpio;
816 	struct resource *res;
817 	int rc;
818 
819 	gpio = devm_kzalloc(&pdev->dev, sizeof(*gpio), GFP_KERNEL);
820 	if (!gpio)
821 		return -ENOMEM;
822 
823 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
824 	gpio->base = devm_ioremap_resource(&pdev->dev, res);
825 	if (IS_ERR(gpio->base))
826 		return PTR_ERR(gpio->base);
827 
828 	spin_lock_init(&gpio->lock);
829 
830 	gpio_id = of_match_node(aspeed_gpio_of_table, pdev->dev.of_node);
831 	if (!gpio_id)
832 		return -EINVAL;
833 
834 	gpio->clk = of_clk_get(pdev->dev.of_node, 0);
835 	if (IS_ERR(gpio->clk)) {
836 		dev_warn(&pdev->dev,
837 				"No HPLL clock phandle provided, debouncing disabled\n");
838 		gpio->clk = NULL;
839 	}
840 
841 	gpio->config = gpio_id->data;
842 
843 	gpio->chip.parent = &pdev->dev;
844 	gpio->chip.ngpio = gpio->config->nr_gpios;
845 	gpio->chip.parent = &pdev->dev;
846 	gpio->chip.direction_input = aspeed_gpio_dir_in;
847 	gpio->chip.direction_output = aspeed_gpio_dir_out;
848 	gpio->chip.get_direction = aspeed_gpio_get_direction;
849 	gpio->chip.request = aspeed_gpio_request;
850 	gpio->chip.free = aspeed_gpio_free;
851 	gpio->chip.get = aspeed_gpio_get;
852 	gpio->chip.set = aspeed_gpio_set;
853 	gpio->chip.set_config = aspeed_gpio_set_config;
854 	gpio->chip.label = dev_name(&pdev->dev);
855 	gpio->chip.base = -1;
856 	gpio->chip.irq_need_valid_mask = true;
857 
858 	rc = devm_gpiochip_add_data(&pdev->dev, &gpio->chip, gpio);
859 	if (rc < 0)
860 		return rc;
861 
862 	gpio->offset_timer =
863 		devm_kzalloc(&pdev->dev, gpio->chip.ngpio, GFP_KERNEL);
864 
865 	return aspeed_gpio_setup_irqs(gpio, pdev);
866 }
867 
868 static struct platform_driver aspeed_gpio_driver = {
869 	.driver = {
870 		.name = KBUILD_MODNAME,
871 		.of_match_table = aspeed_gpio_of_table,
872 	},
873 };
874 
875 module_platform_driver_probe(aspeed_gpio_driver, aspeed_gpio_probe);
876 
877 MODULE_DESCRIPTION("Aspeed GPIO Driver");
878 MODULE_LICENSE("GPL");
879