xref: /linux/drivers/gpio/gpiolib-of.c (revision 2dbc0838bcf24ca59cabc3130cf3b1d6809cdcd4)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * OF helpers for the GPIO API
4  *
5  * Copyright (c) 2007-2008  MontaVista Software, Inc.
6  *
7  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
8  */
9 
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/errno.h>
13 #include <linux/module.h>
14 #include <linux/io.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/of_gpio.h>
19 #include <linux/pinctrl/pinctrl.h>
20 #include <linux/slab.h>
21 #include <linux/gpio/machine.h>
22 
23 #include "gpiolib.h"
24 
25 static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
26 {
27 	struct of_phandle_args *gpiospec = data;
28 
29 	return chip->gpiodev->dev.of_node == gpiospec->np &&
30 				chip->of_xlate &&
31 				chip->of_xlate(chip, gpiospec, NULL) >= 0;
32 }
33 
34 static struct gpio_chip *of_find_gpiochip_by_xlate(
35 					struct of_phandle_args *gpiospec)
36 {
37 	return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
38 }
39 
40 static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
41 					struct of_phandle_args *gpiospec,
42 					enum of_gpio_flags *flags)
43 {
44 	int ret;
45 
46 	if (chip->of_gpio_n_cells != gpiospec->args_count)
47 		return ERR_PTR(-EINVAL);
48 
49 	ret = chip->of_xlate(chip, gpiospec, flags);
50 	if (ret < 0)
51 		return ERR_PTR(ret);
52 
53 	return gpiochip_get_desc(chip, ret);
54 }
55 
56 static void of_gpio_flags_quirks(struct device_node *np,
57 				 const char *propname,
58 				 enum of_gpio_flags *flags,
59 				 int index)
60 {
61 	/*
62 	 * Handle MMC "cd-inverted" and "wp-inverted" semantics.
63 	 */
64 	if (IS_ENABLED(CONFIG_MMC)) {
65 		/*
66 		 * Active low is the default according to the
67 		 * SDHCI specification and the device tree
68 		 * bindings. However the code in the current
69 		 * kernel was written such that the phandle
70 		 * flags were always respected, and "cd-inverted"
71 		 * would invert the flag from the device phandle.
72 		 */
73 		if (!strcmp(propname, "cd-gpios")) {
74 			if (of_property_read_bool(np, "cd-inverted"))
75 				*flags ^= OF_GPIO_ACTIVE_LOW;
76 		}
77 		if (!strcmp(propname, "wp-gpios")) {
78 			if (of_property_read_bool(np, "wp-inverted"))
79 				*flags ^= OF_GPIO_ACTIVE_LOW;
80 		}
81 	}
82 	/*
83 	 * Some GPIO fixed regulator quirks.
84 	 * Note that active low is the default.
85 	 */
86 	if (IS_ENABLED(CONFIG_REGULATOR) &&
87 	    (of_device_is_compatible(np, "regulator-fixed") ||
88 	     of_device_is_compatible(np, "reg-fixed-voltage") ||
89 	     (!(strcmp(propname, "enable-gpio") &&
90 		strcmp(propname, "enable-gpios")) &&
91 	      of_device_is_compatible(np, "regulator-gpio")))) {
92 		/*
93 		 * The regulator GPIO handles are specified such that the
94 		 * presence or absence of "enable-active-high" solely controls
95 		 * the polarity of the GPIO line. Any phandle flags must
96 		 * be actively ignored.
97 		 */
98 		if (*flags & OF_GPIO_ACTIVE_LOW) {
99 			pr_warn("%s GPIO handle specifies active low - ignored\n",
100 				of_node_full_name(np));
101 			*flags &= ~OF_GPIO_ACTIVE_LOW;
102 		}
103 		if (!of_property_read_bool(np, "enable-active-high"))
104 			*flags |= OF_GPIO_ACTIVE_LOW;
105 	}
106 	/*
107 	 * Legacy open drain handling for fixed voltage regulators.
108 	 */
109 	if (IS_ENABLED(CONFIG_REGULATOR) &&
110 	    of_device_is_compatible(np, "reg-fixed-voltage") &&
111 	    of_property_read_bool(np, "gpio-open-drain")) {
112 		*flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN);
113 		pr_info("%s uses legacy open drain flag - update the DTS if you can\n",
114 			of_node_full_name(np));
115 	}
116 
117 	/*
118 	 * Legacy handling of SPI active high chip select. If we have a
119 	 * property named "cs-gpios" we need to inspect the child node
120 	 * to determine if the flags should have inverted semantics.
121 	 *
122 	 * This does not apply to an SPI device named "spi-gpio", because
123 	 * these have traditionally obtained their own GPIOs by parsing
124 	 * the device tree directly and did not respect any "spi-cs-high"
125 	 * property on the SPI bus children.
126 	 */
127 	if (IS_ENABLED(CONFIG_SPI_MASTER) &&
128 	    !strcmp(propname, "cs-gpios") &&
129 	    !of_device_is_compatible(np, "spi-gpio") &&
130 	    of_property_read_bool(np, "cs-gpios")) {
131 		struct device_node *child;
132 		u32 cs;
133 		int ret;
134 
135 		for_each_child_of_node(np, child) {
136 			ret = of_property_read_u32(child, "reg", &cs);
137 			if (ret)
138 				continue;
139 			if (cs == index) {
140 				/*
141 				 * SPI children have active low chip selects
142 				 * by default. This can be specified negatively
143 				 * by just omitting "spi-cs-high" in the
144 				 * device node, or actively by tagging on
145 				 * GPIO_ACTIVE_LOW as flag in the device
146 				 * tree. If the line is simultaneously
147 				 * tagged as active low in the device tree
148 				 * and has the "spi-cs-high" set, we get a
149 				 * conflict and the "spi-cs-high" flag will
150 				 * take precedence.
151 				 */
152 				if (of_property_read_bool(child, "spi-cs-high")) {
153 					if (*flags & OF_GPIO_ACTIVE_LOW) {
154 						pr_warn("%s GPIO handle specifies active low - ignored\n",
155 							of_node_full_name(child));
156 						*flags &= ~OF_GPIO_ACTIVE_LOW;
157 					}
158 				} else {
159 					if (!(*flags & OF_GPIO_ACTIVE_LOW))
160 						pr_info("%s enforce active low on chipselect handle\n",
161 							of_node_full_name(child));
162 					*flags |= OF_GPIO_ACTIVE_LOW;
163 				}
164 				break;
165 			}
166 		}
167 	}
168 
169 	/* Legacy handling of stmmac's active-low PHY reset line */
170 	if (IS_ENABLED(CONFIG_STMMAC_ETH) &&
171 	    !strcmp(propname, "snps,reset-gpio") &&
172 	    of_property_read_bool(np, "snps,reset-active-low"))
173 		*flags |= OF_GPIO_ACTIVE_LOW;
174 }
175 
176 /**
177  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
178  * @np:		device node to get GPIO from
179  * @propname:	property name containing gpio specifier(s)
180  * @index:	index of the GPIO
181  * @flags:	a flags pointer to fill in
182  *
183  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
184  * value on the error condition. If @flags is not NULL the function also fills
185  * in flags for the GPIO.
186  */
187 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
188 		     const char *propname, int index, enum of_gpio_flags *flags)
189 {
190 	struct of_phandle_args gpiospec;
191 	struct gpio_chip *chip;
192 	struct gpio_desc *desc;
193 	int ret;
194 
195 	ret = of_parse_phandle_with_args_map(np, propname, "gpio", index,
196 					     &gpiospec);
197 	if (ret) {
198 		pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n",
199 			__func__, propname, np, index);
200 		return ERR_PTR(ret);
201 	}
202 
203 	chip = of_find_gpiochip_by_xlate(&gpiospec);
204 	if (!chip) {
205 		desc = ERR_PTR(-EPROBE_DEFER);
206 		goto out;
207 	}
208 
209 	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
210 	if (IS_ERR(desc))
211 		goto out;
212 
213 	if (flags)
214 		of_gpio_flags_quirks(np, propname, flags, index);
215 
216 	pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n",
217 		 __func__, propname, np, index,
218 		 PTR_ERR_OR_ZERO(desc));
219 
220 out:
221 	of_node_put(gpiospec.np);
222 
223 	return desc;
224 }
225 
226 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
227 			    int index, enum of_gpio_flags *flags)
228 {
229 	struct gpio_desc *desc;
230 
231 	desc = of_get_named_gpiod_flags(np, list_name, index, flags);
232 
233 	if (IS_ERR(desc))
234 		return PTR_ERR(desc);
235 	else
236 		return desc_to_gpio(desc);
237 }
238 EXPORT_SYMBOL(of_get_named_gpio_flags);
239 
240 /*
241  * The SPI GPIO bindings happened before we managed to establish that GPIO
242  * properties should be named "foo-gpios" so we have this special kludge for
243  * them.
244  */
245 static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id,
246 					  enum of_gpio_flags *of_flags)
247 {
248 	char prop_name[32]; /* 32 is max size of property name */
249 	struct device_node *np = dev->of_node;
250 	struct gpio_desc *desc;
251 
252 	/*
253 	 * Hopefully the compiler stubs the rest of the function if this
254 	 * is false.
255 	 */
256 	if (!IS_ENABLED(CONFIG_SPI_MASTER))
257 		return ERR_PTR(-ENOENT);
258 
259 	/* Allow this specifically for "spi-gpio" devices */
260 	if (!of_device_is_compatible(np, "spi-gpio") || !con_id)
261 		return ERR_PTR(-ENOENT);
262 
263 	/* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */
264 	snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id);
265 
266 	desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags);
267 	return desc;
268 }
269 
270 /*
271  * The old Freescale bindings use simply "gpios" as name for the chip select
272  * lines rather than "cs-gpios" like all other SPI hardware. Account for this
273  * with a special quirk.
274  */
275 static struct gpio_desc *of_find_spi_cs_gpio(struct device *dev,
276 					     const char *con_id,
277 					     unsigned int idx,
278 					     unsigned long *flags)
279 {
280 	struct device_node *np = dev->of_node;
281 
282 	if (!IS_ENABLED(CONFIG_SPI_MASTER))
283 		return ERR_PTR(-ENOENT);
284 
285 	/* Allow this specifically for Freescale devices */
286 	if (!of_device_is_compatible(np, "fsl,spi") &&
287 	    !of_device_is_compatible(np, "aeroflexgaisler,spictrl"))
288 		return ERR_PTR(-ENOENT);
289 	/* Allow only if asking for "cs-gpios" */
290 	if (!con_id || strcmp(con_id, "cs"))
291 		return ERR_PTR(-ENOENT);
292 
293 	/*
294 	 * While all other SPI controllers use "cs-gpios" the Freescale
295 	 * uses just "gpios" so translate to that when "cs-gpios" is
296 	 * requested.
297 	 */
298 	return of_find_gpio(dev, NULL, idx, flags);
299 }
300 
301 /*
302  * Some regulator bindings happened before we managed to establish that GPIO
303  * properties should be named "foo-gpios" so we have this special kludge for
304  * them.
305  */
306 static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id,
307 						enum of_gpio_flags *of_flags)
308 {
309 	/* These are the connection IDs we accept as legacy GPIO phandles */
310 	const char *whitelist[] = {
311 		"wlf,ldoena", /* Arizona */
312 		"wlf,ldo1ena", /* WM8994 */
313 		"wlf,ldo2ena", /* WM8994 */
314 	};
315 	struct device_node *np = dev->of_node;
316 	struct gpio_desc *desc;
317 	int i;
318 
319 	if (!IS_ENABLED(CONFIG_REGULATOR))
320 		return ERR_PTR(-ENOENT);
321 
322 	if (!con_id)
323 		return ERR_PTR(-ENOENT);
324 
325 	i = match_string(whitelist, ARRAY_SIZE(whitelist), con_id);
326 	if (i < 0)
327 		return ERR_PTR(-ENOENT);
328 
329 	desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags);
330 	return desc;
331 }
332 
333 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
334 			       unsigned int idx, unsigned long *flags)
335 {
336 	char prop_name[32]; /* 32 is max size of property name */
337 	enum of_gpio_flags of_flags;
338 	struct gpio_desc *desc;
339 	unsigned int i;
340 
341 	/* Try GPIO property "foo-gpios" and "foo-gpio" */
342 	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
343 		if (con_id)
344 			snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
345 				 gpio_suffixes[i]);
346 		else
347 			snprintf(prop_name, sizeof(prop_name), "%s",
348 				 gpio_suffixes[i]);
349 
350 		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
351 						&of_flags);
352 		/*
353 		 * -EPROBE_DEFER in our case means that we found a
354 		 * valid GPIO property, but no controller has been
355 		 * registered so far.
356 		 *
357 		 * This means we don't need to look any further for
358 		 * alternate name conventions, and we should really
359 		 * preserve the return code for our user to be able to
360 		 * retry probing later.
361 		 */
362 		if (IS_ERR(desc) && PTR_ERR(desc) == -EPROBE_DEFER)
363 			return desc;
364 
365 		if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
366 			break;
367 	}
368 
369 	/* Special handling for SPI GPIOs if used */
370 	if (IS_ERR(desc))
371 		desc = of_find_spi_gpio(dev, con_id, &of_flags);
372 	if (IS_ERR(desc)) {
373 		/* This quirk looks up flags and all */
374 		desc = of_find_spi_cs_gpio(dev, con_id, idx, flags);
375 		if (!IS_ERR(desc))
376 			return desc;
377 	}
378 
379 	/* Special handling for regulator GPIOs if used */
380 	if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER)
381 		desc = of_find_regulator_gpio(dev, con_id, &of_flags);
382 
383 	if (IS_ERR(desc))
384 		return desc;
385 
386 	if (of_flags & OF_GPIO_ACTIVE_LOW)
387 		*flags |= GPIO_ACTIVE_LOW;
388 
389 	if (of_flags & OF_GPIO_SINGLE_ENDED) {
390 		if (of_flags & OF_GPIO_OPEN_DRAIN)
391 			*flags |= GPIO_OPEN_DRAIN;
392 		else
393 			*flags |= GPIO_OPEN_SOURCE;
394 	}
395 
396 	if (of_flags & OF_GPIO_TRANSITORY)
397 		*flags |= GPIO_TRANSITORY;
398 
399 	if (of_flags & OF_GPIO_PULL_UP)
400 		*flags |= GPIO_PULL_UP;
401 	if (of_flags & OF_GPIO_PULL_DOWN)
402 		*flags |= GPIO_PULL_DOWN;
403 
404 	return desc;
405 }
406 
407 /**
408  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
409  * @np:		device node to get GPIO from
410  * @chip:	GPIO chip whose hog is parsed
411  * @idx:	Index of the GPIO to parse
412  * @name:	GPIO line name
413  * @lflags:	bitmask of gpio_lookup_flags GPIO_* values - returned from
414  *		of_find_gpio() or of_parse_own_gpio()
415  * @dflags:	gpiod_flags - optional GPIO initialization flags
416  *
417  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
418  * value on the error condition.
419  */
420 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
421 					   struct gpio_chip *chip,
422 					   unsigned int idx, const char **name,
423 					   unsigned long *lflags,
424 					   enum gpiod_flags *dflags)
425 {
426 	struct device_node *chip_np;
427 	enum of_gpio_flags xlate_flags;
428 	struct of_phandle_args gpiospec;
429 	struct gpio_desc *desc;
430 	unsigned int i;
431 	u32 tmp;
432 	int ret;
433 
434 	chip_np = chip->of_node;
435 	if (!chip_np)
436 		return ERR_PTR(-EINVAL);
437 
438 	xlate_flags = 0;
439 	*lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
440 	*dflags = 0;
441 
442 	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
443 	if (ret)
444 		return ERR_PTR(ret);
445 
446 	gpiospec.np = chip_np;
447 	gpiospec.args_count = tmp;
448 
449 	for (i = 0; i < tmp; i++) {
450 		ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
451 						 &gpiospec.args[i]);
452 		if (ret)
453 			return ERR_PTR(ret);
454 	}
455 
456 	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
457 	if (IS_ERR(desc))
458 		return desc;
459 
460 	if (xlate_flags & OF_GPIO_ACTIVE_LOW)
461 		*lflags |= GPIO_ACTIVE_LOW;
462 	if (xlate_flags & OF_GPIO_TRANSITORY)
463 		*lflags |= GPIO_TRANSITORY;
464 
465 	if (of_property_read_bool(np, "input"))
466 		*dflags |= GPIOD_IN;
467 	else if (of_property_read_bool(np, "output-low"))
468 		*dflags |= GPIOD_OUT_LOW;
469 	else if (of_property_read_bool(np, "output-high"))
470 		*dflags |= GPIOD_OUT_HIGH;
471 	else {
472 		pr_warn("GPIO line %d (%pOFn): no hogging state specified, bailing out\n",
473 			desc_to_gpio(desc), np);
474 		return ERR_PTR(-EINVAL);
475 	}
476 
477 	if (name && of_property_read_string(np, "line-name", name))
478 		*name = np->name;
479 
480 	return desc;
481 }
482 
483 /**
484  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
485  * @chip:	gpio chip to act on
486  *
487  * This is only used by of_gpiochip_add to request/set GPIO initial
488  * configuration.
489  * It returns error if it fails otherwise 0 on success.
490  */
491 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
492 {
493 	struct gpio_desc *desc = NULL;
494 	struct device_node *np;
495 	const char *name;
496 	unsigned long lflags;
497 	enum gpiod_flags dflags;
498 	unsigned int i;
499 	int ret;
500 
501 	for_each_available_child_of_node(chip->of_node, np) {
502 		if (!of_property_read_bool(np, "gpio-hog"))
503 			continue;
504 
505 		for (i = 0;; i++) {
506 			desc = of_parse_own_gpio(np, chip, i, &name, &lflags,
507 						 &dflags);
508 			if (IS_ERR(desc))
509 				break;
510 
511 			ret = gpiod_hog(desc, name, lflags, dflags);
512 			if (ret < 0) {
513 				of_node_put(np);
514 				return ret;
515 			}
516 		}
517 	}
518 
519 	return 0;
520 }
521 
522 /**
523  * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags
524  * @gc:		pointer to the gpio_chip structure
525  * @gpiospec:	GPIO specifier as found in the device tree
526  * @flags:	a flags pointer to fill in
527  *
528  * This is simple translation function, suitable for the most 1:1 mapped
529  * GPIO chips. This function performs only one sanity check: whether GPIO
530  * is less than ngpios (that is specified in the gpio_chip).
531  */
532 int of_gpio_simple_xlate(struct gpio_chip *gc,
533 			 const struct of_phandle_args *gpiospec, u32 *flags)
534 {
535 	/*
536 	 * We're discouraging gpio_cells < 2, since that way you'll have to
537 	 * write your own xlate function (that will have to retrieve the GPIO
538 	 * number and the flags from a single gpio cell -- this is possible,
539 	 * but not recommended).
540 	 */
541 	if (gc->of_gpio_n_cells < 2) {
542 		WARN_ON(1);
543 		return -EINVAL;
544 	}
545 
546 	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
547 		return -EINVAL;
548 
549 	if (gpiospec->args[0] >= gc->ngpio)
550 		return -EINVAL;
551 
552 	if (flags)
553 		*flags = gpiospec->args[1];
554 
555 	return gpiospec->args[0];
556 }
557 EXPORT_SYMBOL(of_gpio_simple_xlate);
558 
559 /**
560  * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
561  * @np:		device node of the GPIO chip
562  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
563  * @data:	driver data to store in the struct gpio_chip
564  *
565  * To use this function you should allocate and fill mm_gc with:
566  *
567  * 1) In the gpio_chip structure:
568  *    - all the callbacks
569  *    - of_gpio_n_cells
570  *    - of_xlate callback (optional)
571  *
572  * 3) In the of_mm_gpio_chip structure:
573  *    - save_regs callback (optional)
574  *
575  * If succeeded, this function will map bank's memory and will
576  * do all necessary work for you. Then you'll able to use .regs
577  * to manage GPIOs from the callbacks.
578  */
579 int of_mm_gpiochip_add_data(struct device_node *np,
580 			    struct of_mm_gpio_chip *mm_gc,
581 			    void *data)
582 {
583 	int ret = -ENOMEM;
584 	struct gpio_chip *gc = &mm_gc->gc;
585 
586 	gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
587 	if (!gc->label)
588 		goto err0;
589 
590 	mm_gc->regs = of_iomap(np, 0);
591 	if (!mm_gc->regs)
592 		goto err1;
593 
594 	gc->base = -1;
595 
596 	if (mm_gc->save_regs)
597 		mm_gc->save_regs(mm_gc);
598 
599 	mm_gc->gc.of_node = np;
600 
601 	ret = gpiochip_add_data(gc, data);
602 	if (ret)
603 		goto err2;
604 
605 	return 0;
606 err2:
607 	iounmap(mm_gc->regs);
608 err1:
609 	kfree(gc->label);
610 err0:
611 	pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret);
612 	return ret;
613 }
614 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
615 
616 /**
617  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
618  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
619  */
620 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
621 {
622 	struct gpio_chip *gc = &mm_gc->gc;
623 
624 	if (!mm_gc)
625 		return;
626 
627 	gpiochip_remove(gc);
628 	iounmap(mm_gc->regs);
629 	kfree(gc->label);
630 }
631 EXPORT_SYMBOL(of_mm_gpiochip_remove);
632 
633 static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
634 {
635 	int len, i;
636 	u32 start, count;
637 	struct device_node *np = chip->of_node;
638 
639 	len = of_property_count_u32_elems(np,  "gpio-reserved-ranges");
640 	if (len < 0 || len % 2 != 0)
641 		return;
642 
643 	for (i = 0; i < len; i += 2) {
644 		of_property_read_u32_index(np, "gpio-reserved-ranges",
645 					   i, &start);
646 		of_property_read_u32_index(np, "gpio-reserved-ranges",
647 					   i + 1, &count);
648 		if (start >= chip->ngpio || start + count >= chip->ngpio)
649 			continue;
650 
651 		bitmap_clear(chip->valid_mask, start, count);
652 	}
653 };
654 
655 #ifdef CONFIG_PINCTRL
656 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
657 {
658 	struct device_node *np = chip->of_node;
659 	struct of_phandle_args pinspec;
660 	struct pinctrl_dev *pctldev;
661 	int index = 0, ret;
662 	const char *name;
663 	static const char group_names_propname[] = "gpio-ranges-group-names";
664 	struct property *group_names;
665 
666 	if (!np)
667 		return 0;
668 
669 	group_names = of_find_property(np, group_names_propname, NULL);
670 
671 	for (;; index++) {
672 		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
673 				index, &pinspec);
674 		if (ret)
675 			break;
676 
677 		pctldev = of_pinctrl_get(pinspec.np);
678 		of_node_put(pinspec.np);
679 		if (!pctldev)
680 			return -EPROBE_DEFER;
681 
682 		if (pinspec.args[2]) {
683 			if (group_names) {
684 				of_property_read_string_index(np,
685 						group_names_propname,
686 						index, &name);
687 				if (strlen(name)) {
688 					pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n",
689 						np);
690 					break;
691 				}
692 			}
693 			/* npins != 0: linear range */
694 			ret = gpiochip_add_pin_range(chip,
695 					pinctrl_dev_get_devname(pctldev),
696 					pinspec.args[0],
697 					pinspec.args[1],
698 					pinspec.args[2]);
699 			if (ret)
700 				return ret;
701 		} else {
702 			/* npins == 0: special range */
703 			if (pinspec.args[1]) {
704 				pr_err("%pOF: Illegal gpio-range format.\n",
705 					np);
706 				break;
707 			}
708 
709 			if (!group_names) {
710 				pr_err("%pOF: GPIO group range requested but no %s property.\n",
711 					np, group_names_propname);
712 				break;
713 			}
714 
715 			ret = of_property_read_string_index(np,
716 						group_names_propname,
717 						index, &name);
718 			if (ret)
719 				break;
720 
721 			if (!strlen(name)) {
722 				pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n",
723 				np);
724 				break;
725 			}
726 
727 			ret = gpiochip_add_pingroup_range(chip, pctldev,
728 						pinspec.args[0], name);
729 			if (ret)
730 				return ret;
731 		}
732 	}
733 
734 	return 0;
735 }
736 
737 #else
738 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
739 #endif
740 
741 int of_gpiochip_add(struct gpio_chip *chip)
742 {
743 	int status;
744 
745 	if (!chip->of_node)
746 		return 0;
747 
748 	if (!chip->of_xlate) {
749 		chip->of_gpio_n_cells = 2;
750 		chip->of_xlate = of_gpio_simple_xlate;
751 	}
752 
753 	if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
754 		return -EINVAL;
755 
756 	of_gpiochip_init_valid_mask(chip);
757 
758 	status = of_gpiochip_add_pin_range(chip);
759 	if (status)
760 		return status;
761 
762 	/* If the chip defines names itself, these take precedence */
763 	if (!chip->names)
764 		devprop_gpiochip_set_names(chip,
765 					   of_fwnode_handle(chip->of_node));
766 
767 	of_node_get(chip->of_node);
768 
769 	status = of_gpiochip_scan_gpios(chip);
770 	if (status) {
771 		of_node_put(chip->of_node);
772 		gpiochip_remove_pin_ranges(chip);
773 	}
774 
775 	return status;
776 }
777 
778 void of_gpiochip_remove(struct gpio_chip *chip)
779 {
780 	gpiochip_remove_pin_ranges(chip);
781 	of_node_put(chip->of_node);
782 }
783