summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpiolib-of.c
blob: 71ba008b7f46a0d65b156756c4992eeffc133e10 (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
/*
 * OF helpers for the GPIO API
 *
 * Copyright (c) 2007-2008  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/gpio/consumer.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/slab.h>
#include <linux/gpio/machine.h>

#include "gpiolib.h"

static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
{
	struct of_phandle_args *gpiospec = data;

	return chip->gpiodev->dev.of_node == gpiospec->np &&
				chip->of_xlate(chip, gpiospec, NULL) >= 0;
}

static struct gpio_chip *of_find_gpiochip_by_xlate(
					struct of_phandle_args *gpiospec)
{
	return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
}

static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
					struct of_phandle_args *gpiospec,
					enum of_gpio_flags *flags)
{
	int ret;

	if (chip->of_gpio_n_cells != gpiospec->args_count)
		return ERR_PTR(-EINVAL);

	ret = chip->of_xlate(chip, gpiospec, flags);
	if (ret < 0)
		return ERR_PTR(ret);

	return gpiochip_get_desc(chip, ret);
}

static void of_gpio_flags_quirks(struct device_node *np,
				 enum of_gpio_flags *flags)
{
	/*
	 * Some GPIO fixed regulator quirks.
	 * Note that active low is the default.
	 */
	if (IS_ENABLED(CONFIG_REGULATOR) &&
	    (of_device_is_compatible(np, "reg-fixed-voltage") ||
	     of_device_is_compatible(np, "regulator-gpio"))) {
		/*
		 * The regulator GPIO handles are specified such that the
		 * presence or absence of "enable-active-high" solely controls
		 * the polarity of the GPIO line. Any phandle flags must
		 * be actively ignored.
		 */
		if (*flags & OF_GPIO_ACTIVE_LOW) {
			pr_warn("%s GPIO handle specifies active low - ignored\n",
				of_node_full_name(np));
			*flags &= ~OF_GPIO_ACTIVE_LOW;
		}
		if (!of_property_read_bool(np, "enable-active-high"))
			*flags |= OF_GPIO_ACTIVE_LOW;
	}
	/*
	 * Legacy open drain handling for fixed voltage regulators.
	 */
	if (IS_ENABLED(CONFIG_REGULATOR) &&
	    of_device_is_compatible(np, "reg-fixed-voltage") &&
	    of_property_read_bool(np, "gpio-open-drain")) {
		*flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN);
		pr_info("%s uses legacy open drain flag - update the DTS if you can\n",
			of_node_full_name(np));
	}
}

/**
 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
 * @np:		device node to get GPIO from
 * @propname:	property name containing gpio specifier(s)
 * @index:	index of the GPIO
 * @flags:	a flags pointer to fill in
 *
 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
 * value on the error condition. If @flags is not NULL the function also fills
 * in flags for the GPIO.
 */
struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
		     const char *propname, int index, enum of_gpio_flags *flags)
{
	struct of_phandle_args gpiospec;
	struct gpio_chip *chip;
	struct gpio_desc *desc;
	int ret;

	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
					 &gpiospec);
	if (ret) {
		pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n",
			__func__, propname, np, index);
		return ERR_PTR(ret);
	}

	chip = of_find_gpiochip_by_xlate(&gpiospec);
	if (!chip) {
		desc = ERR_PTR(-EPROBE_DEFER);
		goto out;
	}

	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
	if (IS_ERR(desc))
		goto out;

	of_gpio_flags_quirks(np, flags);

	pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n",
		 __func__, propname, np, index,
		 PTR_ERR_OR_ZERO(desc));

out:
	of_node_put(gpiospec.np);

	return desc;
}

int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
			    int index, enum of_gpio_flags *flags)
{
	struct gpio_desc *desc;

	desc = of_get_named_gpiod_flags(np, list_name, index, flags);

	if (IS_ERR(desc))
		return PTR_ERR(desc);
	else
		return desc_to_gpio(desc);
}
EXPORT_SYMBOL(of_get_named_gpio_flags);

/*
 * The SPI GPIO bindings happened before we managed to establish that GPIO
 * properties should be named "foo-gpios" so we have this special kludge for
 * them.
 */
static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id,
					  enum of_gpio_flags *of_flags)
{
	char prop_name[32]; /* 32 is max size of property name */
	struct device_node *np = dev->of_node;
	struct gpio_desc *desc;

	/*
	 * Hopefully the compiler stubs the rest of the function if this
	 * is false.
	 */
	if (!IS_ENABLED(CONFIG_SPI_MASTER))
		return ERR_PTR(-ENOENT);

	/* Allow this specifically for "spi-gpio" devices */
	if (!of_device_is_compatible(np, "spi-gpio") || !con_id)
		return ERR_PTR(-ENOENT);

	/* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */
	snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id);

	desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags);
	return desc;
}

/*
 * Some regulator bindings happened before we managed to establish that GPIO
 * properties should be named "foo-gpios" so we have this special kludge for
 * them.
 */
static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id,
						enum of_gpio_flags *of_flags)
{
	/* These are the connection IDs we accept as legacy GPIO phandles */
	const char *whitelist[] = {
		"wlf,ldoena", /* Arizona */
		"wlf,ldo1ena", /* WM8994 */
		"wlf,ldo2ena", /* WM8994 */
	};
	struct device_node *np = dev->of_node;
	struct gpio_desc *desc;
	int i;

	if (!IS_ENABLED(CONFIG_REGULATOR))
		return ERR_PTR(-ENOENT);

	if (!con_id)
		return ERR_PTR(-ENOENT);

	for (i = 0; i < ARRAY_SIZE(whitelist); i++)
		if (!strcmp(con_id, whitelist[i]))
			break;

	if (i == ARRAY_SIZE(whitelist))
		return ERR_PTR(-ENOENT);

	desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags);
	return desc;
}

struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
			       unsigned int idx,
			       enum gpio_lookup_flags *flags)
{
	char prop_name[32]; /* 32 is max size of property name */
	enum of_gpio_flags of_flags;
	struct gpio_desc *desc;
	unsigned int i;

	/* Try GPIO property "foo-gpios" and "foo-gpio" */
	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
		if (con_id)
			snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
				 gpio_suffixes[i]);
		else
			snprintf(prop_name, sizeof(prop_name), "%s",
				 gpio_suffixes[i]);

		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
						&of_flags);
		if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
			break;
	}

	/* Special handling for SPI GPIOs if used */
	if (IS_ERR(desc))
		desc = of_find_spi_gpio(dev, con_id, &of_flags);

	/* Special handling for regulator GPIOs if used */
	if (IS_ERR(desc))
		desc = of_find_regulator_gpio(dev, con_id, &of_flags);

	if (IS_ERR(desc))
		return desc;

	if (of_flags & OF_GPIO_ACTIVE_LOW)
		*flags |= GPIO_ACTIVE_LOW;

	if (of_flags & OF_GPIO_SINGLE_ENDED) {
		if (of_flags & OF_GPIO_OPEN_DRAIN)
			*flags |= GPIO_OPEN_DRAIN;
		else
			*flags |= GPIO_OPEN_SOURCE;
	}

	if (of_flags & OF_GPIO_TRANSITORY)
		*flags |= GPIO_TRANSITORY;

	return desc;
}

/**
 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
 * @np:		device node to get GPIO from
 * @chip:	GPIO chip whose hog is parsed
 * @idx:	Index of the GPIO to parse
 * @name:	GPIO line name
 * @lflags:	gpio_lookup_flags - returned from of_find_gpio() or
 *		of_parse_own_gpio()
 * @dflags:	gpiod_flags - optional GPIO initialization flags
 *
 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
 * value on the error condition.
 */
static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
					   struct gpio_chip *chip,
					   unsigned int idx, const char **name,
					   enum gpio_lookup_flags *lflags,
					   enum gpiod_flags *dflags)
{
	struct device_node *chip_np;
	enum of_gpio_flags xlate_flags;
	struct of_phandle_args gpiospec;
	struct gpio_desc *desc;
	unsigned int i;
	u32 tmp;
	int ret;

	chip_np = chip->of_node;
	if (!chip_np)
		return ERR_PTR(-EINVAL);

	xlate_flags = 0;
	*lflags = 0;
	*dflags = 0;

	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
	if (ret)
		return ERR_PTR(ret);

	gpiospec.np = chip_np;
	gpiospec.args_count = tmp;

	for (i = 0; i < tmp; i++) {
		ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
						 &gpiospec.args[i]);
		if (ret)
			return ERR_PTR(ret);
	}

	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
	if (IS_ERR(desc))
		return desc;

	if (xlate_flags & OF_GPIO_ACTIVE_LOW)
		*lflags |= GPIO_ACTIVE_LOW;
	if (xlate_flags & OF_GPIO_TRANSITORY)
		*lflags |= GPIO_TRANSITORY;

	if (of_property_read_bool(np, "input"))
		*dflags |= GPIOD_IN;
	else if (of_property_read_bool(np, "output-low"))
		*dflags |= GPIOD_OUT_LOW;
	else if (of_property_read_bool(np, "output-high"))
		*dflags |= GPIOD_OUT_HIGH;
	else {
		pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
			desc_to_gpio(desc), np->name);
		return ERR_PTR(-EINVAL);
	}

	if (name && of_property_read_string(np, "line-name", name))
		*name = np->name;

	return desc;
}

/**
 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
 * @chip:	gpio chip to act on
 *
 * This is only used by of_gpiochip_add to request/set GPIO initial
 * configuration.
 * It returns error if it fails otherwise 0 on success.
 */
static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
{
	struct gpio_desc *desc = NULL;
	struct device_node *np;
	const char *name;
	enum gpio_lookup_flags lflags;
	enum gpiod_flags dflags;
	unsigned int i;
	int ret;

	for_each_available_child_of_node(chip->of_node, np) {
		if (!of_property_read_bool(np, "gpio-hog"))
			continue;

		for (i = 0;; i++) {
			desc = of_parse_own_gpio(np, chip, i, &name, &lflags,
						 &dflags);
			if (IS_ERR(desc))
				break;

			ret = gpiod_hog(desc, name, lflags, dflags);
			if (ret < 0) {
				of_node_put(np);
				return ret;
			}
		}
	}

	return 0;
}

/**
 * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags
 * @gc:		pointer to the gpio_chip structure
 * @gpiospec:	GPIO specifier as found in the device tree
 * @flags:	a flags pointer to fill in
 *
 * This is simple translation function, suitable for the most 1:1 mapped
 * GPIO chips. This function performs only one sanity check: whether GPIO
 * is less than ngpios (that is specified in the gpio_chip).
 */
int of_gpio_simple_xlate(struct gpio_chip *gc,
			 const struct of_phandle_args *gpiospec, u32 *flags)
{
	/*
	 * We're discouraging gpio_cells < 2, since that way you'll have to
	 * write your own xlate function (that will have to retrieve the GPIO
	 * number and the flags from a single gpio cell -- this is possible,
	 * but not recommended).
	 */
	if (gc->of_gpio_n_cells < 2) {
		WARN_ON(1);
		return -EINVAL;
	}

	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
		return -EINVAL;

	if (gpiospec->args[0] >= gc->ngpio)
		return -EINVAL;

	if (flags)
		*flags = gpiospec->args[1];

	return gpiospec->args[0];
}
EXPORT_SYMBOL(of_gpio_simple_xlate);

/**
 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
 * @np:		device node of the GPIO chip
 * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
 * @data:	driver data to store in the struct gpio_chip
 *
 * To use this function you should allocate and fill mm_gc with:
 *
 * 1) In the gpio_chip structure:
 *    - all the callbacks
 *    - of_gpio_n_cells
 *    - of_xlate callback (optional)
 *
 * 3) In the of_mm_gpio_chip structure:
 *    - save_regs callback (optional)
 *
 * If succeeded, this function will map bank's memory and will
 * do all necessary work for you. Then you'll able to use .regs
 * to manage GPIOs from the callbacks.
 */
int of_mm_gpiochip_add_data(struct device_node *np,
			    struct of_mm_gpio_chip *mm_gc,
			    void *data)
{
	int ret = -ENOMEM;
	struct gpio_chip *gc = &mm_gc->gc;

	gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
	if (!gc->label)
		goto err0;

	mm_gc->regs = of_iomap(np, 0);
	if (!mm_gc->regs)
		goto err1;

	gc->base = -1;

	if (mm_gc->save_regs)
		mm_gc->save_regs(mm_gc);

	mm_gc->gc.of_node = np;

	ret = gpiochip_add_data(gc, data);
	if (ret)
		goto err2;

	return 0;
err2:
	iounmap(mm_gc->regs);
err1:
	kfree(gc->label);
err0:
	pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret);
	return ret;
}
EXPORT_SYMBOL(of_mm_gpiochip_add_data);

/**
 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
 * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
 */
void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
{
	struct gpio_chip *gc = &mm_gc->gc;

	if (!mm_gc)
		return;

	gpiochip_remove(gc);
	iounmap(mm_gc->regs);
	kfree(gc->label);
}
EXPORT_SYMBOL(of_mm_gpiochip_remove);

#ifdef CONFIG_PINCTRL
static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
{
	struct device_node *np = chip->of_node;
	struct of_phandle_args pinspec;
	struct pinctrl_dev *pctldev;
	int index = 0, ret;
	const char *name;
	static const char group_names_propname[] = "gpio-ranges-group-names";
	struct property *group_names;

	if (!np)
		return 0;

	group_names = of_find_property(np, group_names_propname, NULL);

	for (;; index++) {
		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
				index, &pinspec);
		if (ret)
			break;

		pctldev = of_pinctrl_get(pinspec.np);
		of_node_put(pinspec.np);
		if (!pctldev)
			return -EPROBE_DEFER;

		if (pinspec.args[2]) {
			if (group_names) {
				of_property_read_string_index(np,
						group_names_propname,
						index, &name);
				if (strlen(name)) {
					pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n",
						np);
					break;
				}
			}
			/* npins != 0: linear range */
			ret = gpiochip_add_pin_range(chip,
					pinctrl_dev_get_devname(pctldev),
					pinspec.args[0],
					pinspec.args[1],
					pinspec.args[2]);
			if (ret)
				return ret;
		} else {
			/* npins == 0: special range */
			if (pinspec.args[1]) {
				pr_err("%pOF: Illegal gpio-range format.\n",
					np);
				break;
			}

			if (!group_names) {
				pr_err("%pOF: GPIO group range requested but no %s property.\n",
					np, group_names_propname);
				break;
			}

			ret = of_property_read_string_index(np,
						group_names_propname,
						index, &name);
			if (ret)
				break;

			if (!strlen(name)) {
				pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n",
				np);
				break;
			}

			ret = gpiochip_add_pingroup_range(chip, pctldev,
						pinspec.args[0], name);
			if (ret)
				return ret;
		}
	}

	return 0;
}

#else
static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
#endif

int of_gpiochip_add(struct gpio_chip *chip)
{
	int status;

	if ((!chip->of_node) && (chip->parent))
		chip->of_node = chip->parent->of_node;

	if (!chip->of_node)
		return 0;

	if (!chip->of_xlate) {
		chip->of_gpio_n_cells = 2;
		chip->of_xlate = of_gpio_simple_xlate;
	}

	if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
		return -EINVAL;

	status = of_gpiochip_add_pin_range(chip);
	if (status)
		return status;

	/* If the chip defines names itself, these take precedence */
	if (!chip->names)
		devprop_gpiochip_set_names(chip);

	of_node_get(chip->of_node);

	return of_gpiochip_scan_gpios(chip);
}

void of_gpiochip_remove(struct gpio_chip *chip)
{
	gpiochip_remove_pin_ranges(chip);
	of_node_put(chip->of_node);
}