summaryrefslogtreecommitdiff
path: root/drivers/pinctrl/spear/pinctrl-plgpio.c
blob: 3cf4ecd9302cf6279b87928579c9c39ae28d4316 (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
/*
 * SPEAr platform PLGPIO driver
 *
 * Copyright (C) 2012 ST Microelectronics
 * Viresh Kumar <viresh.kumar@linaro.org>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/clk.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/spinlock.h>
#include <asm/mach/irq.h>

#define MAX_GPIO_PER_REG		32
#define PIN_OFFSET(pin)			(pin % MAX_GPIO_PER_REG)
#define REG_OFFSET(base, reg, pin)	(base + reg + (pin / MAX_GPIO_PER_REG) \
							* sizeof(int *))

/*
 * plgpio pins in all machines are not one to one mapped, bitwise with registers
 * bits. These set of macros define register masks for which below functions
 * (pin_to_offset and offset_to_pin) are required to be called.
 */
#define PTO_ENB_REG		0x001
#define PTO_WDATA_REG		0x002
#define PTO_DIR_REG		0x004
#define PTO_IE_REG		0x008
#define PTO_RDATA_REG		0x010
#define PTO_MIS_REG		0x020

struct plgpio_regs {
	u32 enb;		/* enable register */
	u32 wdata;		/* write data register */
	u32 dir;		/* direction set register */
	u32 rdata;		/* read data register */
	u32 ie;			/* interrupt enable register */
	u32 mis;		/* mask interrupt status register */
	u32 eit;		/* edge interrupt type */
};

/*
 * struct plgpio: plgpio driver specific structure
 *
 * lock: lock for guarding gpio registers
 * base: base address of plgpio block
 * irq_base: irq number of plgpio0
 * chip: gpio framework specific chip information structure
 * p2o: function ptr for pin to offset conversion. This is required only for
 *	machines where mapping b/w pin and offset is not 1-to-1.
 * o2p: function ptr for offset to pin conversion. This is required only for
 *	machines where mapping b/w pin and offset is not 1-to-1.
 * p2o_regs: mask of registers for which p2o and o2p are applicable
 * regs: register offsets
 * csave_regs: context save registers for standby/sleep/hibernate cases
 */
struct plgpio {
	spinlock_t		lock;
	void __iomem		*base;
	struct clk		*clk;
	unsigned		irq_base;
	struct irq_domain	*irq_domain;
	struct gpio_chip	chip;
	int			(*p2o)(int pin);	/* pin_to_offset */
	int			(*o2p)(int offset);	/* offset_to_pin */
	u32			p2o_regs;
	struct plgpio_regs	regs;
#ifdef CONFIG_PM
	struct plgpio_regs	*csave_regs;
#endif
};

/* register manipulation inline functions */
static inline u32 is_plgpio_set(void __iomem *base, u32 pin, u32 reg)
{
	u32 offset = PIN_OFFSET(pin);
	void __iomem *reg_off = REG_OFFSET(base, reg, pin);
	u32 val = readl_relaxed(reg_off);

	return !!(val & (1 << offset));
}

static inline void plgpio_reg_set(void __iomem *base, u32 pin, u32 reg)
{
	u32 offset = PIN_OFFSET(pin);
	void __iomem *reg_off = REG_OFFSET(base, reg, pin);
	u32 val = readl_relaxed(reg_off);

	writel_relaxed(val | (1 << offset), reg_off);
}

static inline void plgpio_reg_reset(void __iomem *base, u32 pin, u32 reg)
{
	u32 offset = PIN_OFFSET(pin);
	void __iomem *reg_off = REG_OFFSET(base, reg, pin);
	u32 val = readl_relaxed(reg_off);

	writel_relaxed(val & ~(1 << offset), reg_off);
}

/* gpio framework specific routines */
static int plgpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
	struct plgpio *plgpio = container_of(chip, struct plgpio, chip);
	unsigned long flags;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & PTO_DIR_REG)) {
		offset = plgpio->p2o(offset);
		if (offset == -1)
			return -EINVAL;
	}

	spin_lock_irqsave(&plgpio->lock, flags);
	plgpio_reg_set(plgpio->base, offset, plgpio->regs.dir);
	spin_unlock_irqrestore(&plgpio->lock, flags);

	return 0;
}

static int plgpio_direction_output(struct gpio_chip *chip, unsigned offset,
		int value)
{
	struct plgpio *plgpio = container_of(chip, struct plgpio, chip);
	unsigned long flags;
	unsigned dir_offset = offset, wdata_offset = offset, tmp;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & (PTO_DIR_REG | PTO_WDATA_REG))) {
		tmp = plgpio->p2o(offset);
		if (tmp == -1)
			return -EINVAL;

		if (plgpio->p2o_regs & PTO_DIR_REG)
			dir_offset = tmp;
		if (plgpio->p2o_regs & PTO_WDATA_REG)
			wdata_offset = tmp;
	}

	spin_lock_irqsave(&plgpio->lock, flags);
	if (value)
		plgpio_reg_set(plgpio->base, wdata_offset,
				plgpio->regs.wdata);
	else
		plgpio_reg_reset(plgpio->base, wdata_offset,
				plgpio->regs.wdata);

	plgpio_reg_reset(plgpio->base, dir_offset, plgpio->regs.dir);
	spin_unlock_irqrestore(&plgpio->lock, flags);

	return 0;
}

static int plgpio_get_value(struct gpio_chip *chip, unsigned offset)
{
	struct plgpio *plgpio = container_of(chip, struct plgpio, chip);

	if (offset >= chip->ngpio)
		return -EINVAL;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & PTO_RDATA_REG)) {
		offset = plgpio->p2o(offset);
		if (offset == -1)
			return -EINVAL;
	}

	return is_plgpio_set(plgpio->base, offset, plgpio->regs.rdata);
}

static void plgpio_set_value(struct gpio_chip *chip, unsigned offset, int value)
{
	struct plgpio *plgpio = container_of(chip, struct plgpio, chip);

	if (offset >= chip->ngpio)
		return;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & PTO_WDATA_REG)) {
		offset = plgpio->p2o(offset);
		if (offset == -1)
			return;
	}

	if (value)
		plgpio_reg_set(plgpio->base, offset, plgpio->regs.wdata);
	else
		plgpio_reg_reset(plgpio->base, offset, plgpio->regs.wdata);
}

static int plgpio_request(struct gpio_chip *chip, unsigned offset)
{
	struct plgpio *plgpio = container_of(chip, struct plgpio, chip);
	int gpio = chip->base + offset;
	unsigned long flags;
	int ret = 0;

	if (offset >= chip->ngpio)
		return -EINVAL;

	ret = pinctrl_request_gpio(gpio);
	if (ret)
		return ret;

	if (!IS_ERR(plgpio->clk)) {
		ret = clk_enable(plgpio->clk);
		if (ret)
			goto err0;
	}

	if (plgpio->regs.enb == -1)
		return 0;

	/*
	 * put gpio in IN mode before enabling it. This make enabling gpio safe
	 */
	ret = plgpio_direction_input(chip, offset);
	if (ret)
		goto err1;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & PTO_ENB_REG)) {
		offset = plgpio->p2o(offset);
		if (offset == -1) {
			ret = -EINVAL;
			goto err1;
		}
	}

	spin_lock_irqsave(&plgpio->lock, flags);
	plgpio_reg_set(plgpio->base, offset, plgpio->regs.enb);
	spin_unlock_irqrestore(&plgpio->lock, flags);
	return 0;

err1:
	if (!IS_ERR(plgpio->clk))
		clk_disable(plgpio->clk);
err0:
	pinctrl_free_gpio(gpio);
	return ret;
}

static void plgpio_free(struct gpio_chip *chip, unsigned offset)
{
	struct plgpio *plgpio = container_of(chip, struct plgpio, chip);
	int gpio = chip->base + offset;
	unsigned long flags;

	if (offset >= chip->ngpio)
		return;

	if (plgpio->regs.enb == -1)
		goto disable_clk;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & PTO_ENB_REG)) {
		offset = plgpio->p2o(offset);
		if (offset == -1)
			return;
	}

	spin_lock_irqsave(&plgpio->lock, flags);
	plgpio_reg_reset(plgpio->base, offset, plgpio->regs.enb);
	spin_unlock_irqrestore(&plgpio->lock, flags);

disable_clk:
	if (!IS_ERR(plgpio->clk))
		clk_disable(plgpio->clk);

	pinctrl_free_gpio(gpio);
}

static int plgpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
	struct plgpio *plgpio = container_of(chip, struct plgpio, chip);

	if (IS_ERR_VALUE(plgpio->irq_base))
		return -EINVAL;

	return irq_find_mapping(plgpio->irq_domain, offset);
}

/* PLGPIO IRQ */
static void plgpio_irq_disable(struct irq_data *d)
{
	struct plgpio *plgpio = irq_data_get_irq_chip_data(d);
	int offset = d->irq - plgpio->irq_base;
	unsigned long flags;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & PTO_IE_REG)) {
		offset = plgpio->p2o(offset);
		if (offset == -1)
			return;
	}

	spin_lock_irqsave(&plgpio->lock, flags);
	plgpio_reg_set(plgpio->base, offset, plgpio->regs.ie);
	spin_unlock_irqrestore(&plgpio->lock, flags);
}

static void plgpio_irq_enable(struct irq_data *d)
{
	struct plgpio *plgpio = irq_data_get_irq_chip_data(d);
	int offset = d->irq - plgpio->irq_base;
	unsigned long flags;

	/* get correct offset for "offset" pin */
	if (plgpio->p2o && (plgpio->p2o_regs & PTO_IE_REG)) {
		offset = plgpio->p2o(offset);
		if (offset == -1)
			return;
	}

	spin_lock_irqsave(&plgpio->lock, flags);
	plgpio_reg_reset(plgpio->base, offset, plgpio->regs.ie);
	spin_unlock_irqrestore(&plgpio->lock, flags);
}

static int plgpio_irq_set_type(struct irq_data *d, unsigned trigger)
{
	struct plgpio *plgpio = irq_data_get_irq_chip_data(d);
	int offset = d->irq - plgpio->irq_base;
	void __iomem *reg_off;
	unsigned int supported_type = 0, val;

	if (offset >= plgpio->chip.ngpio)
		return -EINVAL;

	if (plgpio->regs.eit == -1)
		supported_type = IRQ_TYPE_LEVEL_HIGH;
	else
		supported_type = IRQ_TYPE_EDGE_RISING | IRQ_TYPE_EDGE_FALLING;

	if (!(trigger & supported_type))
		return -EINVAL;

	if (plgpio->regs.eit == -1)
		return 0;

	reg_off = REG_OFFSET(plgpio->base, plgpio->regs.eit, offset);
	val = readl_relaxed(reg_off);

	offset = PIN_OFFSET(offset);
	if (trigger & IRQ_TYPE_EDGE_RISING)
		writel_relaxed(val | (1 << offset), reg_off);
	else
		writel_relaxed(val & ~(1 << offset), reg_off);

	return 0;
}

static struct irq_chip plgpio_irqchip = {
	.name		= "PLGPIO",
	.irq_enable	= plgpio_irq_enable,
	.irq_disable	= plgpio_irq_disable,
	.irq_set_type	= plgpio_irq_set_type,
};

static void plgpio_irq_handler(unsigned irq, struct irq_desc *desc)
{
	struct plgpio *plgpio = irq_get_handler_data(irq);
	struct irq_chip *irqchip = irq_desc_get_chip(desc);
	int regs_count, count, pin, offset, i = 0;
	unsigned long pending;

	count = plgpio->chip.ngpio;
	regs_count = DIV_ROUND_UP(count, MAX_GPIO_PER_REG);

	chained_irq_enter(irqchip, desc);
	/* check all plgpio MIS registers for a possible interrupt */
	for (; i < regs_count; i++) {
		pending = readl_relaxed(plgpio->base + plgpio->regs.mis +
				i * sizeof(int *));
		if (!pending)
			continue;

		/* clear interrupts */
		writel_relaxed(~pending, plgpio->base + plgpio->regs.mis +
				i * sizeof(int *));
		/*
		 * clear extra bits in last register having gpios < MAX/REG
		 * ex: Suppose there are max 102 plgpios. then last register
		 * must have only (102 - MAX_GPIO_PER_REG * 3) = 6 relevant bits
		 * so, we must not take other 28 bits into consideration for
		 * checking interrupt. so clear those bits.
		 */
		count = count - i * MAX_GPIO_PER_REG;
		if (count < MAX_GPIO_PER_REG)
			pending &= (1 << count) - 1;

		for_each_set_bit(offset, &pending, MAX_GPIO_PER_REG) {
			/* get correct pin for "offset" */
			if (plgpio->o2p && (plgpio->p2o_regs & PTO_MIS_REG)) {
				pin = plgpio->o2p(offset);
				if (pin == -1)
					continue;
			} else
				pin = offset;

			/* get correct irq line number */
			pin = i * MAX_GPIO_PER_REG + pin;
			generic_handle_irq(plgpio_to_irq(&plgpio->chip, pin));
		}
	}
	chained_irq_exit(irqchip, desc);
}

/*
 * pin to offset and offset to pin converter functions
 *
 * In spear310 there is inconsistency among bit positions in plgpio regiseters,
 * for different plgpio pins. For example: for pin 27, bit offset is 23, pin
 * 28-33 are not supported, pin 95 has offset bit 95, bit 100 has offset bit 1
 */
static int spear310_p2o(int pin)
{
	int offset = pin;

	if (pin <= 27)
		offset += 4;
	else if (pin <= 33)
		offset = -1;
	else if (pin <= 97)
		offset -= 2;
	else if (pin <= 101)
		offset = 101 - pin;
	else
		offset = -1;

	return offset;
}

int spear310_o2p(int offset)
{
	if (offset <= 3)
		return 101 - offset;
	else if (offset <= 31)
		return offset - 4;
	else
		return offset + 2;
}

static int plgpio_probe_dt(struct platform_device *pdev, struct plgpio *plgpio)
{
	struct device_node *np = pdev->dev.of_node;
	int ret = -EINVAL;
	u32 val;

	if (of_machine_is_compatible("st,spear310")) {
		plgpio->p2o = spear310_p2o;
		plgpio->o2p = spear310_o2p;
		plgpio->p2o_regs = PTO_WDATA_REG | PTO_DIR_REG | PTO_IE_REG |
			PTO_RDATA_REG | PTO_MIS_REG;
	}

	if (!of_property_read_u32(np, "st-plgpio,ngpio", &val)) {
		plgpio->chip.ngpio = val;
	} else {
		dev_err(&pdev->dev, "DT: Invalid ngpio field\n");
		goto end;
	}

	if (!of_property_read_u32(np, "st-plgpio,enb-reg", &val))
		plgpio->regs.enb = val;
	else
		plgpio->regs.enb = -1;

	if (!of_property_read_u32(np, "st-plgpio,wdata-reg", &val)) {
		plgpio->regs.wdata = val;
	} else {
		dev_err(&pdev->dev, "DT: Invalid wdata reg\n");
		goto end;
	}

	if (!of_property_read_u32(np, "st-plgpio,dir-reg", &val)) {
		plgpio->regs.dir = val;
	} else {
		dev_err(&pdev->dev, "DT: Invalid dir reg\n");
		goto end;
	}

	if (!of_property_read_u32(np, "st-plgpio,ie-reg", &val)) {
		plgpio->regs.ie = val;
	} else {
		dev_err(&pdev->dev, "DT: Invalid ie reg\n");
		goto end;
	}

	if (!of_property_read_u32(np, "st-plgpio,rdata-reg", &val)) {
		plgpio->regs.rdata = val;
	} else {
		dev_err(&pdev->dev, "DT: Invalid rdata reg\n");
		goto end;
	}

	if (!of_property_read_u32(np, "st-plgpio,mis-reg", &val)) {
		plgpio->regs.mis = val;
	} else {
		dev_err(&pdev->dev, "DT: Invalid mis reg\n");
		goto end;
	}

	if (!of_property_read_u32(np, "st-plgpio,eit-reg", &val))
		plgpio->regs.eit = val;
	else
		plgpio->regs.eit = -1;

	return 0;

end:
	return ret;
}
static int plgpio_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	struct plgpio *plgpio;
	struct resource *res;
	int ret, irq, i;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(&pdev->dev, "invalid IORESOURCE_MEM\n");
		return -EBUSY;
	}

	plgpio = devm_kzalloc(&pdev->dev, sizeof(*plgpio), GFP_KERNEL);
	if (!plgpio) {
		dev_err(&pdev->dev, "memory allocation fail\n");
		return -ENOMEM;
	}

	plgpio->base = devm_request_and_ioremap(&pdev->dev, res);
	if (!plgpio->base) {
		dev_err(&pdev->dev, "request and ioremap fail\n");
		return -ENOMEM;
	}

	ret = plgpio_probe_dt(pdev, plgpio);
	if (ret) {
		dev_err(&pdev->dev, "DT probe failed\n");
		return ret;
	}

	plgpio->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(plgpio->clk))
		dev_warn(&pdev->dev, "clk_get() failed, work without it\n");

#ifdef CONFIG_PM
	plgpio->csave_regs = devm_kzalloc(&pdev->dev,
			sizeof(*plgpio->csave_regs) *
			DIV_ROUND_UP(plgpio->chip.ngpio, MAX_GPIO_PER_REG),
			GFP_KERNEL);
	if (!plgpio->csave_regs) {
		dev_err(&pdev->dev, "csave registers memory allocation fail\n");
		return -ENOMEM;
	}
#endif

	platform_set_drvdata(pdev, plgpio);
	spin_lock_init(&plgpio->lock);

	plgpio->irq_base = -1;
	plgpio->chip.base = -1;
	plgpio->chip.request = plgpio_request;
	plgpio->chip.free = plgpio_free;
	plgpio->chip.direction_input = plgpio_direction_input;
	plgpio->chip.direction_output = plgpio_direction_output;
	plgpio->chip.get = plgpio_get_value;
	plgpio->chip.set = plgpio_set_value;
	plgpio->chip.to_irq = plgpio_to_irq;
	plgpio->chip.label = dev_name(&pdev->dev);
	plgpio->chip.dev = &pdev->dev;
	plgpio->chip.owner = THIS_MODULE;

	if (!IS_ERR(plgpio->clk)) {
		ret = clk_prepare(plgpio->clk);
		if (ret) {
			dev_err(&pdev->dev, "clk prepare failed\n");
			return ret;
		}
	}

	ret = gpiochip_add(&plgpio->chip);
	if (ret) {
		dev_err(&pdev->dev, "unable to add gpio chip\n");
		goto unprepare_clk;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0) {
		dev_info(&pdev->dev, "irqs not supported\n");
		return 0;
	}

	plgpio->irq_base = irq_alloc_descs(-1, 0, plgpio->chip.ngpio, 0);
	if (IS_ERR_VALUE(plgpio->irq_base)) {
		/* we would not support irq for gpio */
		dev_warn(&pdev->dev, "couldn't allocate irq base\n");
		return 0;
	}

	plgpio->irq_domain = irq_domain_add_legacy(np, plgpio->chip.ngpio,
			plgpio->irq_base, 0, &irq_domain_simple_ops, NULL);
	if (WARN_ON(!plgpio->irq_domain)) {
		dev_err(&pdev->dev, "irq domain init failed\n");
		irq_free_descs(plgpio->irq_base, plgpio->chip.ngpio);
		ret = -ENXIO;
		goto remove_gpiochip;
	}

	irq_set_chained_handler(irq, plgpio_irq_handler);
	for (i = 0; i < plgpio->chip.ngpio; i++) {
		irq_set_chip_and_handler(i + plgpio->irq_base, &plgpio_irqchip,
				handle_simple_irq);
		set_irq_flags(i + plgpio->irq_base, IRQF_VALID);
		irq_set_chip_data(i + plgpio->irq_base, plgpio);
	}

	irq_set_handler_data(irq, plgpio);
	dev_info(&pdev->dev, "PLGPIO registered with IRQs\n");

	return 0;

remove_gpiochip:
	dev_info(&pdev->dev, "Remove gpiochip\n");
	if (gpiochip_remove(&plgpio->chip))
		dev_err(&pdev->dev, "unable to remove gpiochip\n");
unprepare_clk:
	if (!IS_ERR(plgpio->clk))
		clk_unprepare(plgpio->clk);

	return ret;
}

#ifdef CONFIG_PM
static int plgpio_suspend(struct device *dev)
{
	struct plgpio *plgpio = dev_get_drvdata(dev);
	int i, reg_count = DIV_ROUND_UP(plgpio->chip.ngpio, MAX_GPIO_PER_REG);
	void __iomem *off;

	for (i = 0; i < reg_count; i++) {
		off = plgpio->base + i * sizeof(int *);

		if (plgpio->regs.enb != -1)
			plgpio->csave_regs[i].enb =
				readl_relaxed(plgpio->regs.enb + off);
		if (plgpio->regs.eit != -1)
			plgpio->csave_regs[i].eit =
				readl_relaxed(plgpio->regs.eit + off);
		plgpio->csave_regs[i].wdata = readl_relaxed(plgpio->regs.wdata +
				off);
		plgpio->csave_regs[i].dir = readl_relaxed(plgpio->regs.dir +
				off);
		plgpio->csave_regs[i].ie = readl_relaxed(plgpio->regs.ie + off);
	}

	return 0;
}

/*
 * This is used to correct the values in end registers. End registers contain
 * extra bits that might be used for other purpose in platform. So, we shouldn't
 * overwrite these bits. This macro, reads given register again, preserves other
 * bit values (non-plgpio bits), and retain captured value (plgpio bits).
 */
#define plgpio_prepare_reg(__reg, _off, _mask, _tmp)		\
{								\
	_tmp = readl_relaxed(plgpio->regs.__reg + _off);		\
	_tmp &= ~_mask;						\
	plgpio->csave_regs[i].__reg =				\
		_tmp | (plgpio->csave_regs[i].__reg & _mask);	\
}

static int plgpio_resume(struct device *dev)
{
	struct plgpio *plgpio = dev_get_drvdata(dev);
	int i, reg_count = DIV_ROUND_UP(plgpio->chip.ngpio, MAX_GPIO_PER_REG);
	void __iomem *off;
	u32 mask, tmp;

	for (i = 0; i < reg_count; i++) {
		off = plgpio->base + i * sizeof(int *);

		if (i == reg_count - 1) {
			mask = (1 << (plgpio->chip.ngpio - i *
						MAX_GPIO_PER_REG)) - 1;

			if (plgpio->regs.enb != -1)
				plgpio_prepare_reg(enb, off, mask, tmp);

			if (plgpio->regs.eit != -1)
				plgpio_prepare_reg(eit, off, mask, tmp);

			plgpio_prepare_reg(wdata, off, mask, tmp);
			plgpio_prepare_reg(dir, off, mask, tmp);
			plgpio_prepare_reg(ie, off, mask, tmp);
		}

		writel_relaxed(plgpio->csave_regs[i].wdata, plgpio->regs.wdata +
				off);
		writel_relaxed(plgpio->csave_regs[i].dir, plgpio->regs.dir +
				off);

		if (plgpio->regs.eit != -1)
			writel_relaxed(plgpio->csave_regs[i].eit,
					plgpio->regs.eit + off);

		writel_relaxed(plgpio->csave_regs[i].ie, plgpio->regs.ie + off);

		if (plgpio->regs.enb != -1)
			writel_relaxed(plgpio->csave_regs[i].enb,
					plgpio->regs.enb + off);
	}

	return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(plgpio_dev_pm_ops, plgpio_suspend, plgpio_resume);

static const struct of_device_id plgpio_of_match[] = {
	{ .compatible = "st,spear-plgpio" },
	{}
};
MODULE_DEVICE_TABLE(of, plgpio_of_match);

static struct platform_driver plgpio_driver = {
	.probe = plgpio_probe,
	.driver = {
		.owner = THIS_MODULE,
		.name = "spear-plgpio",
		.pm = &plgpio_dev_pm_ops,
		.of_match_table = of_match_ptr(plgpio_of_match),
	},
};

static int __init plgpio_init(void)
{
	return platform_driver_register(&plgpio_driver);
}
subsys_initcall(plgpio_init);

MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
MODULE_DESCRIPTION("ST Microlectronics SPEAr PLGPIO driver");
MODULE_LICENSE("GPL");