summaryrefslogtreecommitdiff
path: root/drivers/pinctrl/pinconf.c
blob: c67c37e23dd77846d2fd3bbd18bf102349064b57 (plain)
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
/*
 * Core driver for the pin config portions of the pin control subsystem
 *
 * Copyright (C) 2011 ST-Ericsson SA
 * Written on behalf of Linaro for ST-Ericsson
 *
 * Author: Linus Walleij <linus.walleij@linaro.org>
 *
 * License terms: GNU General Public License (GPL) version 2
 */
#define pr_fmt(fmt) "pinconfig core: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/uaccess.h>
#include <linux/pinctrl/machine.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/pinctrl/pinconf.h>
#include "core.h"
#include "pinconf.h"

int pinconf_check_ops(struct pinctrl_dev *pctldev)
{
	const struct pinconf_ops *ops = pctldev->desc->confops;

	/* We must be able to read out pin status */
	if (!ops->pin_config_get && !ops->pin_config_group_get) {
		dev_err(pctldev->dev,
			"pinconf must be able to read out pin status\n");
		return -EINVAL;
	}
	/* We have to be able to config the pins in SOME way */
	if (!ops->pin_config_set && !ops->pin_config_group_set) {
		dev_err(pctldev->dev,
			"pinconf has to be able to set a pins config\n");
		return -EINVAL;
	}
	return 0;
}

int pinconf_validate_map(struct pinctrl_map const *map, int i)
{
	if (!map->data.configs.group_or_pin) {
		pr_err("failed to register map %s (%d): no group/pin given\n",
		       map->name, i);
		return -EINVAL;
	}

	if (!map->data.configs.num_configs ||
			!map->data.configs.configs) {
		pr_err("failed to register map %s (%d): no configs given\n",
		       map->name, i);
		return -EINVAL;
	}

	return 0;
}

int pin_config_get_for_pin(struct pinctrl_dev *pctldev, unsigned pin,
			   unsigned long *config)
{
	const struct pinconf_ops *ops = pctldev->desc->confops;

	if (!ops || !ops->pin_config_get) {
		dev_err(pctldev->dev, "cannot get pin configuration, missing "
			"pin_config_get() function in driver\n");
		return -EINVAL;
	}

	return ops->pin_config_get(pctldev, pin, config);
}

/**
 * pin_config_get() - get the configuration of a single pin parameter
 * @dev_name: name of the pin controller device for this pin
 * @name: name of the pin to get the config for
 * @config: the config pointed to by this argument will be filled in with the
 *	current pin state, it can be used directly by drivers as a numeral, or
 *	it can be dereferenced to any struct.
 */
int pin_config_get(const char *dev_name, const char *name,
			  unsigned long *config)
{
	struct pinctrl_dev *pctldev;
	int pin;

	pctldev = get_pinctrl_dev_from_devname(dev_name);
	if (!pctldev) {
		pin = -EINVAL;
		return pin;
	}

	mutex_lock(&pctldev->mutex);

	pin = pin_get_from_name(pctldev, name);
	if (pin < 0)
		goto unlock;

	pin = pin_config_get_for_pin(pctldev, pin, config);

unlock:
	mutex_unlock(&pctldev->mutex);
	return pin;
}
EXPORT_SYMBOL(pin_config_get);

static int pin_config_set_for_pin(struct pinctrl_dev *pctldev, unsigned pin,
			   unsigned long config)
{
	const struct pinconf_ops *ops = pctldev->desc->confops;
	int ret;

	if (!ops || !ops->pin_config_set) {
		dev_err(pctldev->dev, "cannot configure pin, missing "
			"config function in driver\n");
		return -EINVAL;
	}

	ret = ops->pin_config_set(pctldev, pin, config);
	if (ret) {
		dev_err(pctldev->dev,
			"unable to set pin configuration on pin %d\n", pin);
		return ret;
	}

	return 0;
}

/**
 * pin_config_set() - set the configuration of a single pin parameter
 * @dev_name: name of pin controller device for this pin
 * @name: name of the pin to set the config for
 * @config: the config in this argument will contain the desired pin state, it
 *	can be used directly by drivers as a numeral, or it can be dereferenced
 *	to any struct.
 */
int pin_config_set(const char *dev_name, const char *name,
		   unsigned long config)
{
	struct pinctrl_dev *pctldev;
	int pin, ret;

	pctldev = get_pinctrl_dev_from_devname(dev_name);
	if (!pctldev) {
		ret = -EINVAL;
		return ret;
	}

	mutex_lock(&pctldev->mutex);

	pin = pin_get_from_name(pctldev, name);
	if (pin < 0) {
		ret = pin;
		goto unlock;
	}

	ret = pin_config_set_for_pin(pctldev, pin, config);

unlock:
	mutex_unlock(&pctldev->mutex);
	return ret;
}
EXPORT_SYMBOL(pin_config_set);

int pin_config_group_get(const char *dev_name, const char *pin_group,
			 unsigned long *config)
{
	struct pinctrl_dev *pctldev;
	const struct pinconf_ops *ops;
	int selector, ret;

	pctldev = get_pinctrl_dev_from_devname(dev_name);
	if (!pctldev) {
		ret = -EINVAL;
		return ret;
	}

	mutex_lock(&pctldev->mutex);

	ops = pctldev->desc->confops;

	if (!ops || !ops->pin_config_group_get) {
		dev_err(pctldev->dev, "cannot get configuration for pin "
			"group, missing group config get function in "
			"driver\n");
		ret = -EINVAL;
		goto unlock;
	}

	selector = pinctrl_get_group_selector(pctldev, pin_group);
	if (selector < 0) {
		ret = selector;
		goto unlock;
	}

	ret = ops->pin_config_group_get(pctldev, selector, config);

unlock:
	mutex_unlock(&pctldev->mutex);
	return ret;
}
EXPORT_SYMBOL(pin_config_group_get);

int pin_config_group_set(const char *dev_name, const char *pin_group,
			 unsigned long config)
{
	struct pinctrl_dev *pctldev;
	const struct pinconf_ops *ops;
	const struct pinctrl_ops *pctlops;
	int selector;
	const unsigned *pins;
	unsigned num_pins;
	int ret;
	int i;

	pctldev = get_pinctrl_dev_from_devname(dev_name);
	if (!pctldev) {
		ret = -EINVAL;
		return ret;
	}

	mutex_lock(&pctldev->mutex);

	ops = pctldev->desc->confops;
	pctlops = pctldev->desc->pctlops;

	if (!ops || (!ops->pin_config_group_set && !ops->pin_config_set)) {
		dev_err(pctldev->dev, "cannot configure pin group, missing "
			"config function in driver\n");
		ret = -EINVAL;
		goto unlock;
	}

	selector = pinctrl_get_group_selector(pctldev, pin_group);
	if (selector < 0) {
		ret = selector;
		goto unlock;
	}

	ret = pctlops->get_group_pins(pctldev, selector, &pins, &num_pins);
	if (ret) {
		dev_err(pctldev->dev, "cannot configure pin group, error "
			"getting pins\n");
		goto unlock;
	}

	/*
	 * If the pin controller supports handling entire groups we use that
	 * capability.
	 */
	if (ops->pin_config_group_set) {
		ret = ops->pin_config_group_set(pctldev, selector, config);
		/*
		 * If the pin controller prefer that a certain group be handled
		 * pin-by-pin as well, it returns -EAGAIN.
		 */
		if (ret != -EAGAIN)
			goto unlock;
	}

	/*
	 * If the controller cannot handle entire groups, we configure each pin
	 * individually.
	 */
	if (!ops->pin_config_set) {
		ret = 0;
		goto unlock;
	}

	for (i = 0; i < num_pins; i++) {
		ret = ops->pin_config_set(pctldev, pins[i], config);
		if (ret < 0)
			goto unlock;
	}

	ret = 0;

unlock:
	mutex_unlock(&pctldev->mutex);

	return ret;
}
EXPORT_SYMBOL(pin_config_group_set);

int pinconf_map_to_setting(struct pinctrl_map const *map,
			  struct pinctrl_setting *setting)
{
	struct pinctrl_dev *pctldev = setting->pctldev;
	int pin;

	switch (setting->type) {
	case PIN_MAP_TYPE_CONFIGS_PIN:
		pin = pin_get_from_name(pctldev,
					map->data.configs.group_or_pin);
		if (pin < 0) {
			dev_err(pctldev->dev, "could not map pin config for \"%s\"",
				map->data.configs.group_or_pin);
			return pin;
		}
		setting->data.configs.group_or_pin = pin;
		break;
	case PIN_MAP_TYPE_CONFIGS_GROUP:
		pin = pinctrl_get_group_selector(pctldev,
					 map->data.configs.group_or_pin);
		if (pin < 0) {
			dev_err(pctldev->dev, "could not map group config for \"%s\"",
				map->data.configs.group_or_pin);
			return pin;
		}
		setting->data.configs.group_or_pin = pin;
		break;
	default:
		return -EINVAL;
	}

	setting->data.configs.num_configs = map->data.configs.num_configs;
	setting->data.configs.configs = map->data.configs.configs;

	return 0;
}

void pinconf_free_setting(struct pinctrl_setting const *setting)
{
}

int pinconf_apply_setting(struct pinctrl_setting const *setting)
{
	struct pinctrl_dev *pctldev = setting->pctldev;
	const struct pinconf_ops *ops = pctldev->desc->confops;
	int i, ret;

	if (!ops) {
		dev_err(pctldev->dev, "missing confops\n");
		return -EINVAL;
	}

	switch (setting->type) {
	case PIN_MAP_TYPE_CONFIGS_PIN:
		if (!ops->pin_config_set) {
			dev_err(pctldev->dev, "missing pin_config_set op\n");
			return -EINVAL;
		}
		for (i = 0; i < setting->data.configs.num_configs; i++) {
			ret = ops->pin_config_set(pctldev,
					setting->data.configs.group_or_pin,
					setting->data.configs.configs[i]);
			if (ret < 0) {
				dev_err(pctldev->dev,
					"pin_config_set op failed for pin %d config %08lx\n",
					setting->data.configs.group_or_pin,
					setting->data.configs.configs[i]);
				return ret;
			}
		}
		break;
	case PIN_MAP_TYPE_CONFIGS_GROUP:
		if (!ops->pin_config_group_set) {
			dev_err(pctldev->dev,
				"missing pin_config_group_set op\n");
			return -EINVAL;
		}
		for (i = 0; i < setting->data.configs.num_configs; i++) {
			ret = ops->pin_config_group_set(pctldev,
					setting->data.configs.group_or_pin,
					setting->data.configs.configs[i]);
			if (ret < 0) {
				dev_err(pctldev->dev,
					"pin_config_group_set op failed for group %d config %08lx\n",
					setting->data.configs.group_or_pin,
					setting->data.configs.configs[i]);
				return ret;
			}
		}
		break;
	default:
		return -EINVAL;
	}

	return 0;
}

#ifdef CONFIG_DEBUG_FS

void pinconf_show_map(struct seq_file *s, struct pinctrl_map const *map)
{
	struct pinctrl_dev *pctldev;
	const struct pinconf_ops *confops;
	int i;

	pctldev = get_pinctrl_dev_from_devname(map->ctrl_dev_name);
	if (pctldev)
		confops = pctldev->desc->confops;
	else
		confops = NULL;

	switch (map->type) {
	case PIN_MAP_TYPE_CONFIGS_PIN:
		seq_printf(s, "pin ");
		break;
	case PIN_MAP_TYPE_CONFIGS_GROUP:
		seq_printf(s, "group ");
		break;
	default:
		break;
	}

	seq_printf(s, "%s\n", map->data.configs.group_or_pin);

	for (i = 0; i < map->data.configs.num_configs; i++) {
		seq_printf(s, "config ");
		if (confops && confops->pin_config_config_dbg_show)
			confops->pin_config_config_dbg_show(pctldev, s,
						map->data.configs.configs[i]);
		else
			seq_printf(s, "%08lx", map->data.configs.configs[i]);
		seq_printf(s, "\n");
	}
}

void pinconf_show_setting(struct seq_file *s,
			  struct pinctrl_setting const *setting)
{
	struct pinctrl_dev *pctldev = setting->pctldev;
	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
	const struct pinconf_ops *confops = pctldev->desc->confops;
	struct pin_desc *desc;
	int i;

	switch (setting->type) {
	case PIN_MAP_TYPE_CONFIGS_PIN:
		desc = pin_desc_get(setting->pctldev,
				    setting->data.configs.group_or_pin);
		seq_printf(s, "pin %s (%d)",
			   desc->name ? desc->name : "unnamed",
			   setting->data.configs.group_or_pin);
		break;
	case PIN_MAP_TYPE_CONFIGS_GROUP:
		seq_printf(s, "group %s (%d)",
			   pctlops->get_group_name(pctldev,
					setting->data.configs.group_or_pin),
			   setting->data.configs.group_or_pin);
		break;
	default:
		break;
	}

	/*
	 * FIXME: We should really get the pin controler to dump the config
	 * values, so they can be decoded to something meaningful.
	 */
	for (i = 0; i < setting->data.configs.num_configs; i++) {
		seq_printf(s, " ");
		if (confops && confops->pin_config_config_dbg_show)
			confops->pin_config_config_dbg_show(pctldev, s,
				setting->data.configs.configs[i]);
		else
			seq_printf(s, "%08lx",
				   setting->data.configs.configs[i]);
	}

	seq_printf(s, "\n");
}

static void pinconf_dump_pin(struct pinctrl_dev *pctldev,
			     struct seq_file *s, int pin)
{
	const struct pinconf_ops *ops = pctldev->desc->confops;

	/* no-op when not using generic pin config */
	pinconf_generic_dump_pin(pctldev, s, pin);
	if (ops && ops->pin_config_dbg_show)
		ops->pin_config_dbg_show(pctldev, s, pin);
}

static int pinconf_pins_show(struct seq_file *s, void *what)
{
	struct pinctrl_dev *pctldev = s->private;
	const struct pinconf_ops *ops = pctldev->desc->confops;
	unsigned i, pin;

	if (!ops || !ops->pin_config_get)
		return 0;

	seq_puts(s, "Pin config settings per pin\n");
	seq_puts(s, "Format: pin (name): configs\n");

	mutex_lock(&pctldev->mutex);

	/* The pin number can be retrived from the pin controller descriptor */
	for (i = 0; i < pctldev->desc->npins; i++) {
		struct pin_desc *desc;

		pin = pctldev->desc->pins[i].number;
		desc = pin_desc_get(pctldev, pin);
		/* Skip if we cannot search the pin */
		if (desc == NULL)
			continue;

		seq_printf(s, "pin %d (%s):", pin,
			   desc->name ? desc->name : "unnamed");

		pinconf_dump_pin(pctldev, s, pin);

		seq_printf(s, "\n");
	}

	mutex_unlock(&pctldev->mutex);

	return 0;
}

static void pinconf_dump_group(struct pinctrl_dev *pctldev,
			       struct seq_file *s, unsigned selector,
			       const char *gname)
{
	const struct pinconf_ops *ops = pctldev->desc->confops;

	/* no-op when not using generic pin config */
	pinconf_generic_dump_group(pctldev, s, gname);
	if (ops && ops->pin_config_group_dbg_show)
		ops->pin_config_group_dbg_show(pctldev, s, selector);
}

static int pinconf_groups_show(struct seq_file *s, void *what)
{
	struct pinctrl_dev *pctldev = s->private;
	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
	const struct pinconf_ops *ops = pctldev->desc->confops;
	unsigned ngroups = pctlops->get_groups_count(pctldev);
	unsigned selector = 0;

	if (!ops || !ops->pin_config_group_get)
		return 0;

	seq_puts(s, "Pin config settings per pin group\n");
	seq_puts(s, "Format: group (name): configs\n");

	while (selector < ngroups) {
		const char *gname = pctlops->get_group_name(pctldev, selector);

		seq_printf(s, "%u (%s):", selector, gname);
		pinconf_dump_group(pctldev, s, selector, gname);
		seq_printf(s, "\n");

		selector++;
	}

	return 0;
}

static int pinconf_pins_open(struct inode *inode, struct file *file)
{
	return single_open(file, pinconf_pins_show, inode->i_private);
}

static int pinconf_groups_open(struct inode *inode, struct file *file)
{
	return single_open(file, pinconf_groups_show, inode->i_private);
}

static const struct file_operations pinconf_pins_ops = {
	.open		= pinconf_pins_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

static const struct file_operations pinconf_groups_ops = {
	.open		= pinconf_groups_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
};

#define MAX_NAME_LEN 15

struct dbg_cfg {
	enum pinctrl_map_type map_type;
	char dev_name[MAX_NAME_LEN+1];
	char state_name[MAX_NAME_LEN+1];
	char pin_name[MAX_NAME_LEN+1];
};

/*
 * Goal is to keep this structure as global in order to simply read the
 * pinconf-config file after a write to check config is as expected
 */
static struct dbg_cfg pinconf_dbg_conf;

/**
 * pinconf_dbg_config_print() - display the pinctrl config from the pinctrl
 * map, of the dev/pin/state that was last written to pinconf-config file.
 * @s: string filled in  with config description
 * @d: not used
 */
static int pinconf_dbg_config_print(struct seq_file *s, void *d)
{
	struct pinctrl_maps *maps_node;
	const struct pinctrl_map *map;
	struct pinctrl_dev *pctldev = NULL;
	const struct pinconf_ops *confops = NULL;
	const struct pinctrl_map_configs *configs;
	struct dbg_cfg *dbg = &pinconf_dbg_conf;
	int i, j;
	bool found = false;
	unsigned long config;

	mutex_lock(&pctldev->mutex);

	/* Parse the pinctrl map and look for the elected pin/state */
	for_each_maps(maps_node, i, map) {
		if (map->type != dbg->map_type)
			continue;
		if (strcmp(map->dev_name, dbg->dev_name))
			continue;
		if (strcmp(map->name, dbg->state_name))
			continue;

		for (j = 0; j < map->data.configs.num_configs; j++) {
			if (!strcmp(map->data.configs.group_or_pin,
					dbg->pin_name)) {
				/*
				 * We found the right pin / state, read the
				 * config and he pctldev for later use
				 */
				configs = &map->data.configs;
				pctldev = get_pinctrl_dev_from_devname
					(map->ctrl_dev_name);
				found = true;
				break;
			}
		}
	}

	if (!found) {
		seq_printf(s, "No config found for dev/state/pin, expected:\n");
		seq_printf(s, "Searched dev:%s\n", dbg->dev_name);
		seq_printf(s, "Searched state:%s\n", dbg->state_name);
		seq_printf(s, "Searched pin:%s\n", dbg->pin_name);
		seq_printf(s, "Use: modify config_pin <devname> "\
				"<state> <pinname> <value>\n");
		goto exit;
	}

	config = *(configs->configs);
	seq_printf(s, "Dev %s has config of %s in state %s: 0x%08lX\n",
			dbg->dev_name, dbg->pin_name,
			dbg->state_name, config);

	if (pctldev)
		confops = pctldev->desc->confops;

	if (confops && confops->pin_config_config_dbg_show)
		confops->pin_config_config_dbg_show(pctldev, s, config);

exit:
	mutex_unlock(&pctldev->mutex);

	return 0;
}

/**
 * pinconf_dbg_config_write() - modify the pinctrl config in the pinctrl
 * map, of a dev/pin/state entry based on user entries to pinconf-config
 * @user_buf: contains the modification request with expected format:
 *     modify config_pin <devicename> <state> <pinname> <newvalue>
 * modify is literal string, alternatives like add/delete not supported yet
 * config_pin is literal, alternatives like config_mux not supported yet
 * <devicename> <state> <pinname> are values that should match the pinctrl-maps
 * <newvalue> reflects the new config and is driver dependant
 */
static int pinconf_dbg_config_write(struct file *file,
	const char __user *user_buf, size_t count, loff_t *ppos)
{
	struct pinctrl_maps *maps_node;
	const struct pinctrl_map *map;
	struct pinctrl_dev *pctldev = NULL;
	const struct pinconf_ops *confops = NULL;
	struct dbg_cfg *dbg = &pinconf_dbg_conf;
	const struct pinctrl_map_configs *configs;
	char config[MAX_NAME_LEN+1];
	bool found = false;
	char buf[128];
	char *b = &buf[0];
	int buf_size;
	char *token;
	int i;

	/* Get userspace string and assure termination */
	buf_size = min(count, (sizeof(buf)-1));
	if (copy_from_user(buf, user_buf, buf_size))
		return -EFAULT;
	buf[buf_size] = 0;

	/*
	 * need to parse entry and extract parameters:
	 * modify configs_pin devicename state pinname newvalue
	 */

	/* Get arg: 'modify' */
	token = strsep(&b, " ");
	if (!token)
		return -EINVAL;
	if (strcmp(token, "modify"))
		return -EINVAL;

	/* Get arg type: "config_pin" type supported so far */
	token = strsep(&b, " ");
	if (!token)
		return -EINVAL;
	if (strcmp(token, "config_pin"))
		return -EINVAL;
	dbg->map_type = PIN_MAP_TYPE_CONFIGS_PIN;

	/* get arg 'device_name' */
	token = strsep(&b, " ");
	if (token == NULL)
		return -EINVAL;
	if (strlen(token) >= MAX_NAME_LEN)
		return -EINVAL;
	strncpy(dbg->dev_name, token, MAX_NAME_LEN);

	/* get arg 'state_name' */
	token = strsep(&b, " ");
	if (token == NULL)
		return -EINVAL;
	if (strlen(token) >= MAX_NAME_LEN)
		return -EINVAL;
	strncpy(dbg->state_name, token, MAX_NAME_LEN);

	/* get arg 'pin_name' */
	token = strsep(&b, " ");
	if (token == NULL)
		return -EINVAL;
	if (strlen(token) >= MAX_NAME_LEN)
		return -EINVAL;
	strncpy(dbg->pin_name, token, MAX_NAME_LEN);

	/* get new_value of config' */
	token = strsep(&b, " ");
	if (token == NULL)
		return -EINVAL;
	if (strlen(token) >= MAX_NAME_LEN)
		return -EINVAL;
	strncpy(config, token, MAX_NAME_LEN);

	mutex_lock(&pinctrl_maps_mutex);

	/* Parse the pinctrl map and look for the selected dev/state/pin */
	for_each_maps(maps_node, i, map) {
		if (strcmp(map->dev_name, dbg->dev_name))
			continue;
		if (map->type != dbg->map_type)
			continue;
		if (strcmp(map->name, dbg->state_name))
			continue;

		/*  we found the right pin / state, so overwrite config */
		if (!strcmp(map->data.configs.group_or_pin, dbg->pin_name)) {
			found = true;
			pctldev = get_pinctrl_dev_from_devname(
					map->ctrl_dev_name);
			configs = &map->data.configs;
			break;
		}
	}

	if (!found) {
		count = -EINVAL;
		goto exit;
	}

	if (pctldev)
		confops = pctldev->desc->confops;

	if (confops && confops->pin_config_dbg_parse_modify) {
		for (i = 0; i < configs->num_configs; i++) {
			confops->pin_config_dbg_parse_modify(pctldev,
						     config,
						     &configs->configs[i]);
		}
	}

exit:
	mutex_unlock(&pinctrl_maps_mutex);

	return count;
}

static int pinconf_dbg_config_open(struct inode *inode, struct file *file)
{
	return single_open(file, pinconf_dbg_config_print, inode->i_private);
}

static const struct file_operations pinconf_dbg_pinconfig_fops = {
	.open = pinconf_dbg_config_open,
	.write = pinconf_dbg_config_write,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	.owner = THIS_MODULE,
};

void pinconf_init_device_debugfs(struct dentry *devroot,
			 struct pinctrl_dev *pctldev)
{
	debugfs_create_file("pinconf-pins", S_IFREG | S_IRUGO,
			    devroot, pctldev, &pinconf_pins_ops);
	debugfs_create_file("pinconf-groups", S_IFREG | S_IRUGO,
			    devroot, pctldev, &pinconf_groups_ops);
	debugfs_create_file("pinconf-config",  (S_IRUGO | S_IWUSR | S_IWGRP),
			    devroot, pctldev, &pinconf_dbg_pinconfig_fops);
}

#endif