xref: /linux/drivers/gpio/gpiolib-of.c (revision ecb41832bd2a7a3f8ac93527cec5e51e3827daed)
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 
170 /**
171  * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
172  * @np:		device node to get GPIO from
173  * @propname:	property name containing gpio specifier(s)
174  * @index:	index of the GPIO
175  * @flags:	a flags pointer to fill in
176  *
177  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
178  * value on the error condition. If @flags is not NULL the function also fills
179  * in flags for the GPIO.
180  */
181 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
182 		     const char *propname, int index, enum of_gpio_flags *flags)
183 {
184 	struct of_phandle_args gpiospec;
185 	struct gpio_chip *chip;
186 	struct gpio_desc *desc;
187 	int ret;
188 
189 	ret = of_parse_phandle_with_args_map(np, propname, "gpio", index,
190 					     &gpiospec);
191 	if (ret) {
192 		pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n",
193 			__func__, propname, np, index);
194 		return ERR_PTR(ret);
195 	}
196 
197 	chip = of_find_gpiochip_by_xlate(&gpiospec);
198 	if (!chip) {
199 		desc = ERR_PTR(-EPROBE_DEFER);
200 		goto out;
201 	}
202 
203 	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
204 	if (IS_ERR(desc))
205 		goto out;
206 
207 	if (flags)
208 		of_gpio_flags_quirks(np, propname, flags, index);
209 
210 	pr_debug("%s: parsed '%s' property of node '%pOF[%d]' - status (%d)\n",
211 		 __func__, propname, np, index,
212 		 PTR_ERR_OR_ZERO(desc));
213 
214 out:
215 	of_node_put(gpiospec.np);
216 
217 	return desc;
218 }
219 
220 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
221 			    int index, enum of_gpio_flags *flags)
222 {
223 	struct gpio_desc *desc;
224 
225 	desc = of_get_named_gpiod_flags(np, list_name, index, flags);
226 
227 	if (IS_ERR(desc))
228 		return PTR_ERR(desc);
229 	else
230 		return desc_to_gpio(desc);
231 }
232 EXPORT_SYMBOL(of_get_named_gpio_flags);
233 
234 /*
235  * The SPI GPIO bindings happened before we managed to establish that GPIO
236  * properties should be named "foo-gpios" so we have this special kludge for
237  * them.
238  */
239 static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id,
240 					  enum of_gpio_flags *of_flags)
241 {
242 	char prop_name[32]; /* 32 is max size of property name */
243 	struct device_node *np = dev->of_node;
244 	struct gpio_desc *desc;
245 
246 	/*
247 	 * Hopefully the compiler stubs the rest of the function if this
248 	 * is false.
249 	 */
250 	if (!IS_ENABLED(CONFIG_SPI_MASTER))
251 		return ERR_PTR(-ENOENT);
252 
253 	/* Allow this specifically for "spi-gpio" devices */
254 	if (!of_device_is_compatible(np, "spi-gpio") || !con_id)
255 		return ERR_PTR(-ENOENT);
256 
257 	/* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */
258 	snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id);
259 
260 	desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags);
261 	return desc;
262 }
263 
264 /*
265  * Some regulator bindings happened before we managed to establish that GPIO
266  * properties should be named "foo-gpios" so we have this special kludge for
267  * them.
268  */
269 static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id,
270 						enum of_gpio_flags *of_flags)
271 {
272 	/* These are the connection IDs we accept as legacy GPIO phandles */
273 	const char *whitelist[] = {
274 		"wlf,ldoena", /* Arizona */
275 		"wlf,ldo1ena", /* WM8994 */
276 		"wlf,ldo2ena", /* WM8994 */
277 	};
278 	struct device_node *np = dev->of_node;
279 	struct gpio_desc *desc;
280 	int i;
281 
282 	if (!IS_ENABLED(CONFIG_REGULATOR))
283 		return ERR_PTR(-ENOENT);
284 
285 	if (!con_id)
286 		return ERR_PTR(-ENOENT);
287 
288 	i = match_string(whitelist, ARRAY_SIZE(whitelist), con_id);
289 	if (i < 0)
290 		return ERR_PTR(-ENOENT);
291 
292 	desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags);
293 	return desc;
294 }
295 
296 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
297 			       unsigned int idx, unsigned long *flags)
298 {
299 	char prop_name[32]; /* 32 is max size of property name */
300 	enum of_gpio_flags of_flags;
301 	struct gpio_desc *desc;
302 	unsigned int i;
303 
304 	/* Try GPIO property "foo-gpios" and "foo-gpio" */
305 	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
306 		if (con_id)
307 			snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
308 				 gpio_suffixes[i]);
309 		else
310 			snprintf(prop_name, sizeof(prop_name), "%s",
311 				 gpio_suffixes[i]);
312 
313 		desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
314 						&of_flags);
315 		/*
316 		 * -EPROBE_DEFER in our case means that we found a
317 		 * valid GPIO property, but no controller has been
318 		 * registered so far.
319 		 *
320 		 * This means we don't need to look any further for
321 		 * alternate name conventions, and we should really
322 		 * preserve the return code for our user to be able to
323 		 * retry probing later.
324 		 */
325 		if (IS_ERR(desc) && PTR_ERR(desc) == -EPROBE_DEFER)
326 			return desc;
327 
328 		if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
329 			break;
330 	}
331 
332 	/* Special handling for SPI GPIOs if used */
333 	if (IS_ERR(desc))
334 		desc = of_find_spi_gpio(dev, con_id, &of_flags);
335 
336 	/* Special handling for regulator GPIOs if used */
337 	if (IS_ERR(desc) && PTR_ERR(desc) != -EPROBE_DEFER)
338 		desc = of_find_regulator_gpio(dev, con_id, &of_flags);
339 
340 	if (IS_ERR(desc))
341 		return desc;
342 
343 	if (of_flags & OF_GPIO_ACTIVE_LOW)
344 		*flags |= GPIO_ACTIVE_LOW;
345 
346 	if (of_flags & OF_GPIO_SINGLE_ENDED) {
347 		if (of_flags & OF_GPIO_OPEN_DRAIN)
348 			*flags |= GPIO_OPEN_DRAIN;
349 		else
350 			*flags |= GPIO_OPEN_SOURCE;
351 	}
352 
353 	if (of_flags & OF_GPIO_TRANSITORY)
354 		*flags |= GPIO_TRANSITORY;
355 
356 	if (of_flags & OF_GPIO_PULL_UP)
357 		*flags |= GPIO_PULL_UP;
358 	if (of_flags & OF_GPIO_PULL_DOWN)
359 		*flags |= GPIO_PULL_DOWN;
360 
361 	return desc;
362 }
363 
364 /**
365  * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
366  * @np:		device node to get GPIO from
367  * @chip:	GPIO chip whose hog is parsed
368  * @idx:	Index of the GPIO to parse
369  * @name:	GPIO line name
370  * @lflags:	bitmask of gpio_lookup_flags GPIO_* values - returned from
371  *		of_find_gpio() or of_parse_own_gpio()
372  * @dflags:	gpiod_flags - optional GPIO initialization flags
373  *
374  * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
375  * value on the error condition.
376  */
377 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
378 					   struct gpio_chip *chip,
379 					   unsigned int idx, const char **name,
380 					   unsigned long *lflags,
381 					   enum gpiod_flags *dflags)
382 {
383 	struct device_node *chip_np;
384 	enum of_gpio_flags xlate_flags;
385 	struct of_phandle_args gpiospec;
386 	struct gpio_desc *desc;
387 	unsigned int i;
388 	u32 tmp;
389 	int ret;
390 
391 	chip_np = chip->of_node;
392 	if (!chip_np)
393 		return ERR_PTR(-EINVAL);
394 
395 	xlate_flags = 0;
396 	*lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
397 	*dflags = 0;
398 
399 	ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
400 	if (ret)
401 		return ERR_PTR(ret);
402 
403 	gpiospec.np = chip_np;
404 	gpiospec.args_count = tmp;
405 
406 	for (i = 0; i < tmp; i++) {
407 		ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
408 						 &gpiospec.args[i]);
409 		if (ret)
410 			return ERR_PTR(ret);
411 	}
412 
413 	desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
414 	if (IS_ERR(desc))
415 		return desc;
416 
417 	if (xlate_flags & OF_GPIO_ACTIVE_LOW)
418 		*lflags |= GPIO_ACTIVE_LOW;
419 	if (xlate_flags & OF_GPIO_TRANSITORY)
420 		*lflags |= GPIO_TRANSITORY;
421 
422 	if (of_property_read_bool(np, "input"))
423 		*dflags |= GPIOD_IN;
424 	else if (of_property_read_bool(np, "output-low"))
425 		*dflags |= GPIOD_OUT_LOW;
426 	else if (of_property_read_bool(np, "output-high"))
427 		*dflags |= GPIOD_OUT_HIGH;
428 	else {
429 		pr_warn("GPIO line %d (%pOFn): no hogging state specified, bailing out\n",
430 			desc_to_gpio(desc), np);
431 		return ERR_PTR(-EINVAL);
432 	}
433 
434 	if (name && of_property_read_string(np, "line-name", name))
435 		*name = np->name;
436 
437 	return desc;
438 }
439 
440 /**
441  * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
442  * @chip:	gpio chip to act on
443  *
444  * This is only used by of_gpiochip_add to request/set GPIO initial
445  * configuration.
446  * It returns error if it fails otherwise 0 on success.
447  */
448 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
449 {
450 	struct gpio_desc *desc = NULL;
451 	struct device_node *np;
452 	const char *name;
453 	unsigned long lflags;
454 	enum gpiod_flags dflags;
455 	unsigned int i;
456 	int ret;
457 
458 	for_each_available_child_of_node(chip->of_node, np) {
459 		if (!of_property_read_bool(np, "gpio-hog"))
460 			continue;
461 
462 		for (i = 0;; i++) {
463 			desc = of_parse_own_gpio(np, chip, i, &name, &lflags,
464 						 &dflags);
465 			if (IS_ERR(desc))
466 				break;
467 
468 			ret = gpiod_hog(desc, name, lflags, dflags);
469 			if (ret < 0) {
470 				of_node_put(np);
471 				return ret;
472 			}
473 		}
474 	}
475 
476 	return 0;
477 }
478 
479 /**
480  * of_gpio_simple_xlate - translate gpiospec to the GPIO number and flags
481  * @gc:		pointer to the gpio_chip structure
482  * @gpiospec:	GPIO specifier as found in the device tree
483  * @flags:	a flags pointer to fill in
484  *
485  * This is simple translation function, suitable for the most 1:1 mapped
486  * GPIO chips. This function performs only one sanity check: whether GPIO
487  * is less than ngpios (that is specified in the gpio_chip).
488  */
489 int of_gpio_simple_xlate(struct gpio_chip *gc,
490 			 const struct of_phandle_args *gpiospec, u32 *flags)
491 {
492 	/*
493 	 * We're discouraging gpio_cells < 2, since that way you'll have to
494 	 * write your own xlate function (that will have to retrieve the GPIO
495 	 * number and the flags from a single gpio cell -- this is possible,
496 	 * but not recommended).
497 	 */
498 	if (gc->of_gpio_n_cells < 2) {
499 		WARN_ON(1);
500 		return -EINVAL;
501 	}
502 
503 	if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
504 		return -EINVAL;
505 
506 	if (gpiospec->args[0] >= gc->ngpio)
507 		return -EINVAL;
508 
509 	if (flags)
510 		*flags = gpiospec->args[1];
511 
512 	return gpiospec->args[0];
513 }
514 EXPORT_SYMBOL(of_gpio_simple_xlate);
515 
516 /**
517  * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
518  * @np:		device node of the GPIO chip
519  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
520  * @data:	driver data to store in the struct gpio_chip
521  *
522  * To use this function you should allocate and fill mm_gc with:
523  *
524  * 1) In the gpio_chip structure:
525  *    - all the callbacks
526  *    - of_gpio_n_cells
527  *    - of_xlate callback (optional)
528  *
529  * 3) In the of_mm_gpio_chip structure:
530  *    - save_regs callback (optional)
531  *
532  * If succeeded, this function will map bank's memory and will
533  * do all necessary work for you. Then you'll able to use .regs
534  * to manage GPIOs from the callbacks.
535  */
536 int of_mm_gpiochip_add_data(struct device_node *np,
537 			    struct of_mm_gpio_chip *mm_gc,
538 			    void *data)
539 {
540 	int ret = -ENOMEM;
541 	struct gpio_chip *gc = &mm_gc->gc;
542 
543 	gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
544 	if (!gc->label)
545 		goto err0;
546 
547 	mm_gc->regs = of_iomap(np, 0);
548 	if (!mm_gc->regs)
549 		goto err1;
550 
551 	gc->base = -1;
552 
553 	if (mm_gc->save_regs)
554 		mm_gc->save_regs(mm_gc);
555 
556 	mm_gc->gc.of_node = np;
557 
558 	ret = gpiochip_add_data(gc, data);
559 	if (ret)
560 		goto err2;
561 
562 	return 0;
563 err2:
564 	iounmap(mm_gc->regs);
565 err1:
566 	kfree(gc->label);
567 err0:
568 	pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret);
569 	return ret;
570 }
571 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
572 
573 /**
574  * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
575  * @mm_gc:	pointer to the of_mm_gpio_chip allocated structure
576  */
577 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
578 {
579 	struct gpio_chip *gc = &mm_gc->gc;
580 
581 	if (!mm_gc)
582 		return;
583 
584 	gpiochip_remove(gc);
585 	iounmap(mm_gc->regs);
586 	kfree(gc->label);
587 }
588 EXPORT_SYMBOL(of_mm_gpiochip_remove);
589 
590 static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
591 {
592 	int len, i;
593 	u32 start, count;
594 	struct device_node *np = chip->of_node;
595 
596 	len = of_property_count_u32_elems(np,  "gpio-reserved-ranges");
597 	if (len < 0 || len % 2 != 0)
598 		return;
599 
600 	for (i = 0; i < len; i += 2) {
601 		of_property_read_u32_index(np, "gpio-reserved-ranges",
602 					   i, &start);
603 		of_property_read_u32_index(np, "gpio-reserved-ranges",
604 					   i + 1, &count);
605 		if (start >= chip->ngpio || start + count >= chip->ngpio)
606 			continue;
607 
608 		bitmap_clear(chip->valid_mask, start, count);
609 	}
610 };
611 
612 #ifdef CONFIG_PINCTRL
613 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
614 {
615 	struct device_node *np = chip->of_node;
616 	struct of_phandle_args pinspec;
617 	struct pinctrl_dev *pctldev;
618 	int index = 0, ret;
619 	const char *name;
620 	static const char group_names_propname[] = "gpio-ranges-group-names";
621 	struct property *group_names;
622 
623 	if (!np)
624 		return 0;
625 
626 	group_names = of_find_property(np, group_names_propname, NULL);
627 
628 	for (;; index++) {
629 		ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
630 				index, &pinspec);
631 		if (ret)
632 			break;
633 
634 		pctldev = of_pinctrl_get(pinspec.np);
635 		of_node_put(pinspec.np);
636 		if (!pctldev)
637 			return -EPROBE_DEFER;
638 
639 		if (pinspec.args[2]) {
640 			if (group_names) {
641 				of_property_read_string_index(np,
642 						group_names_propname,
643 						index, &name);
644 				if (strlen(name)) {
645 					pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n",
646 						np);
647 					break;
648 				}
649 			}
650 			/* npins != 0: linear range */
651 			ret = gpiochip_add_pin_range(chip,
652 					pinctrl_dev_get_devname(pctldev),
653 					pinspec.args[0],
654 					pinspec.args[1],
655 					pinspec.args[2]);
656 			if (ret)
657 				return ret;
658 		} else {
659 			/* npins == 0: special range */
660 			if (pinspec.args[1]) {
661 				pr_err("%pOF: Illegal gpio-range format.\n",
662 					np);
663 				break;
664 			}
665 
666 			if (!group_names) {
667 				pr_err("%pOF: GPIO group range requested but no %s property.\n",
668 					np, group_names_propname);
669 				break;
670 			}
671 
672 			ret = of_property_read_string_index(np,
673 						group_names_propname,
674 						index, &name);
675 			if (ret)
676 				break;
677 
678 			if (!strlen(name)) {
679 				pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n",
680 				np);
681 				break;
682 			}
683 
684 			ret = gpiochip_add_pingroup_range(chip, pctldev,
685 						pinspec.args[0], name);
686 			if (ret)
687 				return ret;
688 		}
689 	}
690 
691 	return 0;
692 }
693 
694 #else
695 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
696 #endif
697 
698 int of_gpiochip_add(struct gpio_chip *chip)
699 {
700 	int status;
701 
702 	if (!chip->of_node)
703 		return 0;
704 
705 	if (!chip->of_xlate) {
706 		chip->of_gpio_n_cells = 2;
707 		chip->of_xlate = of_gpio_simple_xlate;
708 	}
709 
710 	if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
711 		return -EINVAL;
712 
713 	of_gpiochip_init_valid_mask(chip);
714 
715 	status = of_gpiochip_add_pin_range(chip);
716 	if (status)
717 		return status;
718 
719 	/* If the chip defines names itself, these take precedence */
720 	if (!chip->names)
721 		devprop_gpiochip_set_names(chip,
722 					   of_fwnode_handle(chip->of_node));
723 
724 	of_node_get(chip->of_node);
725 
726 	status = of_gpiochip_scan_gpios(chip);
727 	if (status) {
728 		of_node_put(chip->of_node);
729 		gpiochip_remove_pin_ranges(chip);
730 	}
731 
732 	return status;
733 }
734 
735 void of_gpiochip_remove(struct gpio_chip *chip)
736 {
737 	gpiochip_remove_pin_ranges(chip);
738 	of_node_put(chip->of_node);
739 }
740