summaryrefslogtreecommitdiff
path: root/drivers/pinctrl/pinmux.c
blob: 7342c26f4246f87f47eb9fa34a6ef46ce92835d4 (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
/*
 * Core driver for the pin muxing portions of the pin control subsystem
 *
 * Copyright (C) 2011-2012 ST-Ericsson SA
 * Written on behalf of Linaro for ST-Ericsson
 * Based on bits of regulator core, gpio core and clk core
 *
 * Author: Linus Walleij <linus.walleij@linaro.org>
 *
 * License terms: GNU General Public License (GPL) version 2
 */
#define pr_fmt(fmt) "pinmux core: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/radix-tree.h>
#include <linux/err.h>
#include <linux/list.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/pinctrl/machine.h>
#include <linux/pinctrl/pinmux.h>
#include "core.h"
#include "pinmux.h"

/**
 * struct pinmux_group - group list item for pinmux groups
 * @node: pinmux group list node
 * @func_selector: the function selector for the pinmux device handling
 *	this pinmux
 * @group_selector: the group selector for this group
 */
struct pinmux_group {
	struct list_head node;
	unsigned func_selector;
	unsigned group_selector;
};

int pinmux_check_ops(struct pinctrl_dev *pctldev)
{
	const struct pinmux_ops *ops = pctldev->desc->pmxops;
	unsigned selector = 0;

	/* Check that we implement required operations */
	if (!ops->list_functions ||
	    !ops->get_function_name ||
	    !ops->get_function_groups ||
	    !ops->enable ||
	    !ops->disable)
		return -EINVAL;

	/* Check that all functions registered have names */
	while (ops->list_functions(pctldev, selector) >= 0) {
		const char *fname = ops->get_function_name(pctldev,
							   selector);
		if (!fname) {
			pr_err("pinmux ops has no name for function%u\n",
				selector);
			return -EINVAL;
		}
		selector++;
	}

	return 0;
}

/**
 * pin_request() - request a single pin to be muxed in, typically for GPIO
 * @pin: the pin number in the global pin space
 * @owner: a representation of the owner of this pin; typically the device
 *	name that controls its mux function, or the requested GPIO name
 * @gpio_range: the range matching the GPIO pin if this is a request for a
 *	single GPIO pin
 */
static int pin_request(struct pinctrl_dev *pctldev,
		       int pin, const char *owner,
		       struct pinctrl_gpio_range *gpio_range)
{
	struct pin_desc *desc;
	const struct pinmux_ops *ops = pctldev->desc->pmxops;
	int status = -EINVAL;

	dev_dbg(pctldev->dev, "request pin %d for %s\n", pin, owner);

	desc = pin_desc_get(pctldev, pin);
	if (desc == NULL) {
		dev_err(pctldev->dev,
			"pin is not registered so it cannot be requested\n");
		goto out;
	}

	if (desc->owner && strcmp(desc->owner, owner)) {
		dev_err(pctldev->dev,
			"pin already requested\n");
		goto out;
	}
	desc->owner = owner;

	/* Let each pin increase references to this module */
	if (!try_module_get(pctldev->owner)) {
		dev_err(pctldev->dev,
			"could not increase module refcount for pin %d\n",
			pin);
		status = -EINVAL;
		goto out_free_pin;
	}

	/*
	 * If there is no kind of request function for the pin we just assume
	 * we got it by default and proceed.
	 */
	if (gpio_range && ops->gpio_request_enable)
		/* This requests and enables a single GPIO pin */
		status = ops->gpio_request_enable(pctldev, gpio_range, pin);
	else if (ops->request)
		status = ops->request(pctldev, pin);
	else
		status = 0;

	if (status)
		dev_err(pctldev->dev, "->request on device %s failed for pin %d\n",
		       pctldev->desc->name, pin);
out_free_pin:
	if (status)
		desc->owner = NULL;
out:
	if (status)
		dev_err(pctldev->dev, "pin-%d (%s) status %d\n",
		       pin, owner, status);

	return status;
}

/**
 * pin_free() - release a single muxed in pin so something else can be muxed
 * @pctldev: pin controller device handling this pin
 * @pin: the pin to free
 * @gpio_range: the range matching the GPIO pin if this is a request for a
 *	single GPIO pin
 *
 * This function returns a pointer to the previous owner. This is used
 * for callers that dynamically allocate an owner name so it can be freed
 * once the pin is free. This is done for GPIO request functions.
 */
static const char *pin_free(struct pinctrl_dev *pctldev, int pin,
			    struct pinctrl_gpio_range *gpio_range)
{
	const struct pinmux_ops *ops = pctldev->desc->pmxops;
	struct pin_desc *desc;
	const char *owner;

	desc = pin_desc_get(pctldev, pin);
	if (desc == NULL) {
		dev_err(pctldev->dev,
			"pin is not registered so it cannot be freed\n");
		return NULL;
	}

	/*
	 * If there is no kind of request function for the pin we just assume
	 * we got it by default and proceed.
	 */
	if (gpio_range && ops->gpio_disable_free)
		ops->gpio_disable_free(pctldev, gpio_range, pin);
	else if (ops->free)
		ops->free(pctldev, pin);

	owner = desc->owner;
	desc->owner = NULL;
	module_put(pctldev->owner);

	return owner;
}

/**
 * pinmux_request_gpio() - request pinmuxing for a GPIO pin
 * @pctldev: pin controller device affected
 * @pin: the pin to mux in for GPIO
 * @range: the applicable GPIO range
 */
int pinmux_request_gpio(struct pinctrl_dev *pctldev,
			struct pinctrl_gpio_range *range,
			unsigned pin, unsigned gpio)
{
	char gpiostr[16];
	const char *owner;
	int ret;

	/* Conjure some name stating what chip and pin this is taken by */
	snprintf(gpiostr, 15, "%s:%d", range->name, gpio);

	owner = kstrdup(gpiostr, GFP_KERNEL);
	if (!owner)
		return -EINVAL;

	ret = pin_request(pctldev, pin, owner, range);
	if (ret < 0)
		kfree(owner);

	return ret;
}

/**
 * pinmux_free_gpio() - release a pin from GPIO muxing
 * @pctldev: the pin controller device for the pin
 * @pin: the affected currently GPIO-muxed in pin
 * @range: applicable GPIO range
 */
void pinmux_free_gpio(struct pinctrl_dev *pctldev, unsigned pin,
		      struct pinctrl_gpio_range *range)
{
	const char *owner;

	owner = pin_free(pctldev, pin, range);
	kfree(owner);
}

/**
 * pinmux_gpio_direction() - set the direction of a single muxed-in GPIO pin
 * @pctldev: the pin controller handling this pin
 * @range: applicable GPIO range
 * @pin: the affected GPIO pin in this controller
 * @input: true if we set the pin as input, false for output
 */
int pinmux_gpio_direction(struct pinctrl_dev *pctldev,
			  struct pinctrl_gpio_range *range,
			  unsigned pin, bool input)
{
	const struct pinmux_ops *ops;
	int ret;

	ops = pctldev->desc->pmxops;

	if (ops->gpio_set_direction)
		ret = ops->gpio_set_direction(pctldev, range, pin, input);
	else
		ret = 0;

	return ret;
}

/**
 * acquire_pins() - acquire all the pins for a certain function on a pinmux
 * @pctldev: the device to take the pins on
 * @owner: a representation of the owner of this pin; typically the device
 *	name that controls its mux function
 * @group_selector: the group selector containing the pins to acquire
 */
static int acquire_pins(struct pinctrl_dev *pctldev,
			const char *owner,
			unsigned group_selector)
{
	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
	const unsigned *pins;
	unsigned num_pins;
	int ret;
	int i;

	ret = pctlops->get_group_pins(pctldev, group_selector,
				      &pins, &num_pins);
	if (ret)
		return ret;

	dev_dbg(pctldev->dev, "requesting the %u pins from group %u\n",
		num_pins, group_selector);

	/* Try to allocate all pins in this group, one by one */
	for (i = 0; i < num_pins; i++) {
		ret = pin_request(pctldev, pins[i], owner, NULL);
		if (ret) {
			dev_err(pctldev->dev,
				"could not get request pin %d on device %s - conflicting mux mappings?\n",
				pins[i],
				pinctrl_dev_get_name(pctldev));
			/* On error release all taken pins */
			i--; /* this pin just failed */
			for (; i >= 0; i--)
				pin_free(pctldev, pins[i], NULL);
			return -ENODEV;
		}
	}
	return 0;
}

/**
 * release_pins() - release pins taken by earlier acquirement
 * @pctldev: the device to free the pins on
 * @group_selector: the group selector containing the pins to free
 */
static void release_pins(struct pinctrl_dev *pctldev,
			 unsigned group_selector)
{
	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
	const unsigned *pins;
	unsigned num_pins;
	int ret;
	int i;

	ret = pctlops->get_group_pins(pctldev, group_selector,
				      &pins, &num_pins);
	if (ret) {
		dev_err(pctldev->dev, "could not get pins to release for group selector %d\n",
			group_selector);
		return;
	}
	for (i = 0; i < num_pins; i++)
		pin_free(pctldev, pins[i], NULL);
}

/**
 * pinmux_check_pin_group() - check function and pin group combo
 * @pctldev: device to check the pin group vs function for
 * @func_selector: the function selector to check the pin group for, we have
 *	already looked this up in the calling function
 * @pin_group: the pin group to match to the function
 *
 * This function will check that the pinmux driver can supply the
 * selected pin group for a certain function, returns the group selector if
 * the group and function selector will work fine together, else returns
 * negative
 */
static int pinmux_check_pin_group(struct pinctrl_dev *pctldev,
				  unsigned func_selector,
				  const char *pin_group)
{
	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
	const struct pinctrl_ops *pctlops = pctldev->desc->pctlops;
	int ret;

	/*
	 * If the driver does not support different pin groups for the
	 * functions, we only support group 0, and assume this exists.
	 */
	if (!pctlops || !pctlops->list_groups)
		return 0;

	/*
	 * Passing NULL (no specific group) will select the first and
	 * hopefully only group of pins available for this function.
	 */
	if (!pin_group) {
		char const * const *groups;
		unsigned num_groups;

		ret = pmxops->get_function_groups(pctldev, func_selector,
						  &groups, &num_groups);
		if (ret)
			return ret;
		if (num_groups < 1)
			return -EINVAL;
		ret = pinctrl_get_group_selector(pctldev, groups[0]);
		if (ret < 0) {
			dev_err(pctldev->dev,
				"function %s wants group %s but the pin controller does not seem to have that group\n",
				pmxops->get_function_name(pctldev, func_selector),
				groups[0]);
			return ret;
		}

		if (num_groups > 1)
			dev_dbg(pctldev->dev,
				"function %s support more than one group, default-selecting first group %s (%d)\n",
				pmxops->get_function_name(pctldev, func_selector),
				groups[0],
				ret);

		return ret;
	}

	dev_dbg(pctldev->dev,
		"check if we have pin group %s on controller %s\n",
		pin_group, pinctrl_dev_get_name(pctldev));

	ret = pinctrl_get_group_selector(pctldev, pin_group);
	if (ret < 0) {
		dev_dbg(pctldev->dev,
			"%s does not support pin group %s with function %s\n",
			pinctrl_dev_get_name(pctldev),
			pin_group,
			pmxops->get_function_name(pctldev, func_selector));
	}
	return ret;
}

/**
 * pinmux_search_function() - check pin control driver for a certain function
 * @pctldev: device to check for function and position
 * @map: function map containing the function and position to look for
 * @func_selector: returns the applicable function selector if found
 * @group_selector: returns the applicable group selector if found
 *
 * This will search the pinmux driver for an applicable
 * function with a specific pin group, returns 0 if these can be mapped
 * negative otherwise
 */
static int pinmux_search_function(struct pinctrl_dev *pctldev,
				  struct pinctrl_map const *map,
				  unsigned *func_selector,
				  unsigned *group_selector)
{
	const struct pinmux_ops *ops = pctldev->desc->pmxops;
	unsigned selector = 0;

	/* See if this pctldev has this function */
	while (ops->list_functions(pctldev, selector) >= 0) {
		const char *fname = ops->get_function_name(pctldev,
							   selector);
		int ret;

		if (!strcmp(map->function, fname)) {
			/* Found the function, check pin group */
			ret = pinmux_check_pin_group(pctldev, selector,
						     map->group);
			if (ret < 0)
				return ret;

			/* This function and group selector can be used */
			*func_selector = selector;
			*group_selector = ret;
			return 0;

		}
		selector++;
	}

	pr_err("%s does not support function %s\n",
	       pinctrl_dev_get_name(pctldev), map->function);
	return -EINVAL;
}

/**
 * pinmux_enable_muxmap() - enable a map entry for a certain pinmux
 */
static int pinmux_enable_muxmap(struct pinctrl_dev *pctldev,
				struct pinctrl *p,
				struct device *dev,
				const char *devname,
				struct pinctrl_map const *map)
{
	unsigned func_selector;
	unsigned group_selector;
	struct pinmux_group *grp;
	int ret;

	/*
	 * Note that we're not locking the pinmux mutex here, because
	 * this is only called at pinmux initialization time when it
	 * has not been added to any list and thus is not reachable
	 * by anyone else.
	 */

	if (p->pctldev && p->pctldev != pctldev) {
		dev_err(pctldev->dev,
			"different pin control devices given for device %s, function %s\n",
			devname, map->function);
		return -EINVAL;
	}
	p->dev = dev;
	p->pctldev = pctldev;

	/* Now go into the driver and try to match a function and group */
	ret = pinmux_search_function(pctldev, map, &func_selector,
				     &group_selector);
	if (ret < 0)
		return ret;

	/* Now add this group selector, we may have many of them */
	grp = kmalloc(sizeof(*grp), GFP_KERNEL);
	if (!grp)
		return -ENOMEM;
	grp->func_selector = func_selector;
	grp->group_selector = group_selector;
	ret = acquire_pins(pctldev, devname, group_selector);
	if (ret) {
		kfree(grp);
		return ret;
	}
	list_add_tail(&grp->node, &p->groups);

	return 0;
}

/**
 * pinmux_apply_muxmap() - apply a certain mux mapping entry
 */
int pinmux_apply_muxmap(struct pinctrl_dev *pctldev,
			struct pinctrl *p,
			struct device *dev,
			const char *devname,
			struct pinctrl_map const *map)
{
	int ret;

	ret = pinmux_enable_muxmap(pctldev, p, dev,
				   devname, map);
	if (ret) {
		pinmux_put(p);
		return ret;
	}

	return 0;
}

/**
 * pinmux_put() - free up the pinmux portions of a pin controller handle
 */
void pinmux_put(struct pinctrl *p)
{
	struct list_head *node, *tmp;

	list_for_each_safe(node, tmp, &p->groups) {
		struct pinmux_group *grp =
			list_entry(node, struct pinmux_group, node);
		/* Release all pins taken by this group */
		release_pins(p->pctldev, grp->group_selector);
		list_del(node);
		kfree(grp);
	}
}

/**
 * pinmux_enable() - enable the pinmux portion of a pin control handle
 */
int pinmux_enable(struct pinctrl *p)
{
	struct pinctrl_dev *pctldev = p->pctldev;
	const struct pinmux_ops *ops = pctldev->desc->pmxops;
	struct pinmux_group *grp;
	int ret;

	list_for_each_entry(grp, &p->groups, node) {
		ret = ops->enable(pctldev, grp->func_selector,
				  grp->group_selector);
		if (ret)
			/*
			 * TODO: call disable() on all groups we called
			 * enable() on to this point?
			 */
			return ret;
	}
	return 0;
}

/**
 * pinmux_disable() - disable the pinmux portions of a pin control handle
 */
void pinmux_disable(struct pinctrl *p)
{
	struct pinctrl_dev *pctldev = p->pctldev;
	const struct pinmux_ops *ops = pctldev->desc->pmxops;
	struct pinmux_group *grp;

	list_for_each_entry(grp, &p->groups, node) {
		ops->disable(pctldev, grp->func_selector,
			     grp->group_selector);
	}
}

#ifdef CONFIG_DEBUG_FS

/* Called from pincontrol core */
static int pinmux_functions_show(struct seq_file *s, void *what)
{
	struct pinctrl_dev *pctldev = s->private;
	const struct pinmux_ops *pmxops = pctldev->desc->pmxops;
	unsigned func_selector = 0;

	mutex_lock(&pinctrl_mutex);

	while (pmxops->list_functions(pctldev, func_selector) >= 0) {
		const char *func = pmxops->get_function_name(pctldev,
							  func_selector);
		const char * const *groups;
		unsigned num_groups;
		int ret;
		int i;

		ret = pmxops->get_function_groups(pctldev, func_selector,
						  &groups, &num_groups);
		if (ret)
			seq_printf(s, "function %s: COULD NOT GET GROUPS\n",
				   func);

		seq_printf(s, "function: %s, groups = [ ", func);
		for (i = 0; i < num_groups; i++)
			seq_printf(s, "%s ", groups[i]);
		seq_puts(s, "]\n");

		func_selector++;
	}

	mutex_unlock(&pinctrl_mutex);

	return 0;
}

static int pinmux_pins_show(struct seq_file *s, void *what)
{
	struct pinctrl_dev *pctldev = s->private;
	unsigned i, pin;

	seq_puts(s, "Pinmux settings per pin\n");
	seq_puts(s, "Format: pin (name): owner\n");

	mutex_lock(&pinctrl_mutex);

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

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

		if (desc->owner &&
		    !strcmp(desc->owner, pinctrl_dev_get_name(pctldev)))
			is_hog = true;

		seq_printf(s, "pin %d (%s): %s%s\n", pin,
			   desc->name ? desc->name : "unnamed",
			   desc->owner ? desc->owner : "UNCLAIMED",
			   is_hog ? " (HOG)" : "");
	}

	mutex_unlock(&pinctrl_mutex);

	return 0;
}

void pinmux_dbg_show(struct seq_file *s, struct pinctrl *p)
{
	struct pinctrl_dev *pctldev = p->pctldev;
	const struct pinmux_ops *pmxops;
	const struct pinctrl_ops *pctlops;
	struct pinmux_group *grp;
	const char *sep = "";

	pmxops = pctldev->desc->pmxops;
	pctlops = pctldev->desc->pctlops;

	seq_printf(s, " groups: [");
	list_for_each_entry(grp, &p->groups, node) {
		seq_printf(s, "%s%s (%u)=%s (%u)",
			   sep,
			   pctlops->get_group_name(pctldev,
						   grp->group_selector),
			   grp->group_selector,
			   pmxops->get_function_name(pctldev,
						     grp->func_selector),
			   grp->func_selector);
		sep = ", ";
	}
	seq_printf(s, " ]");
}

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

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

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

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

void pinmux_init_device_debugfs(struct dentry *devroot,
			 struct pinctrl_dev *pctldev)
{
	debugfs_create_file("pinmux-functions", S_IFREG | S_IRUGO,
			    devroot, pctldev, &pinmux_functions_ops);
	debugfs_create_file("pinmux-pins", S_IFREG | S_IRUGO,
			    devroot, pctldev, &pinmux_pins_ops);
}

#endif /* CONFIG_DEBUG_FS */