1 // SPDX-License-Identifier: GPL-2.0+
3 * OF helpers for the GPIO API
5 * Copyright (c) 2007-2008 MontaVista Software, Inc.
7 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
10 #include <linux/device.h>
11 #include <linux/err.h>
12 #include <linux/errno.h>
13 #include <linux/module.h>
15 #include <linux/gpio/consumer.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>
25 static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
27 struct of_phandle_args *gpiospec = data;
29 return chip->gpiodev->dev.of_node == gpiospec->np &&
31 chip->of_xlate(chip, gpiospec, NULL) >= 0;
34 static struct gpio_chip *of_find_gpiochip_by_xlate(
35 struct of_phandle_args *gpiospec)
37 return gpiochip_find(gpiospec, of_gpiochip_match_node_and_xlate);
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)
46 if (chip->of_gpio_n_cells != gpiospec->args_count)
47 return ERR_PTR(-EINVAL);
49 ret = chip->of_xlate(chip, gpiospec, flags);
53 return gpiochip_get_desc(chip, ret);
56 static void of_gpio_flags_quirks(struct device_node *np,
58 enum of_gpio_flags *flags,
62 * Handle MMC "cd-inverted" and "wp-inverted" semantics.
64 if (IS_ENABLED(CONFIG_MMC)) {
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.
73 if (!strcmp(propname, "cd-gpios")) {
74 if (of_property_read_bool(np, "cd-inverted"))
75 *flags ^= OF_GPIO_ACTIVE_LOW;
77 if (!strcmp(propname, "wp-gpios")) {
78 if (of_property_read_bool(np, "wp-inverted"))
79 *flags ^= OF_GPIO_ACTIVE_LOW;
83 * Some GPIO fixed regulator quirks.
84 * Note that active low is the default.
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")))) {
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.
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;
103 if (!of_property_read_bool(np, "enable-active-high"))
104 *flags |= OF_GPIO_ACTIVE_LOW;
107 * Legacy open drain handling for fixed voltage regulators.
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));
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.
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.
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;
135 for_each_child_of_node(np, child) {
136 ret = of_property_read_u32(child, "reg", &cs);
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
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;
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;
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;
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
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.
187 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
188 const char *propname, int index, enum of_gpio_flags *flags)
190 struct of_phandle_args gpiospec;
191 struct gpio_chip *chip;
192 struct gpio_desc *desc;
195 ret = of_parse_phandle_with_args_map(np, propname, "gpio", index,
198 pr_debug("%s: can't parse '%s' property of node '%pOF[%d]'\n",
199 __func__, propname, np, index);
203 chip = of_find_gpiochip_by_xlate(&gpiospec);
205 desc = ERR_PTR(-EPROBE_DEFER);
209 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, flags);
214 of_gpio_flags_quirks(np, propname, flags, index);
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));
221 of_node_put(gpiospec.np);
226 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
227 int index, enum of_gpio_flags *flags)
229 struct gpio_desc *desc;
231 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
234 return PTR_ERR(desc);
236 return desc_to_gpio(desc);
238 EXPORT_SYMBOL(of_get_named_gpio_flags);
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
245 static struct gpio_desc *of_find_spi_gpio(struct device *dev, const char *con_id,
246 enum of_gpio_flags *of_flags)
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;
253 * Hopefully the compiler stubs the rest of the function if this
256 if (!IS_ENABLED(CONFIG_SPI_MASTER))
257 return ERR_PTR(-ENOENT);
259 /* Allow this specifically for "spi-gpio" devices */
260 if (!of_device_is_compatible(np, "spi-gpio") || !con_id)
261 return ERR_PTR(-ENOENT);
263 /* Will be "gpio-sck", "gpio-mosi" or "gpio-miso" */
264 snprintf(prop_name, sizeof(prop_name), "%s-%s", "gpio", con_id);
266 desc = of_get_named_gpiod_flags(np, prop_name, 0, of_flags);
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.
275 static struct gpio_desc *of_find_spi_cs_gpio(struct device *dev,
278 unsigned long *flags)
280 struct device_node *np = dev->of_node;
282 if (!IS_ENABLED(CONFIG_SPI_MASTER))
283 return ERR_PTR(-ENOENT);
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);
294 * While all other SPI controllers use "cs-gpios" the Freescale
295 * uses just "gpios" so translate to that when "cs-gpios" is
298 return of_find_gpio(dev, NULL, idx, flags);
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
306 static struct gpio_desc *of_find_regulator_gpio(struct device *dev, const char *con_id,
307 enum of_gpio_flags *of_flags)
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 */
315 struct device_node *np = dev->of_node;
316 struct gpio_desc *desc;
319 if (!IS_ENABLED(CONFIG_REGULATOR))
320 return ERR_PTR(-ENOENT);
323 return ERR_PTR(-ENOENT);
325 i = match_string(whitelist, ARRAY_SIZE(whitelist), con_id);
327 return ERR_PTR(-ENOENT);
329 desc = of_get_named_gpiod_flags(np, con_id, 0, of_flags);
333 struct gpio_desc *of_find_gpio(struct device *dev, const char *con_id,
334 unsigned int idx, unsigned long *flags)
336 char prop_name[32]; /* 32 is max size of property name */
337 enum of_gpio_flags of_flags;
338 struct gpio_desc *desc;
341 /* Try GPIO property "foo-gpios" and "foo-gpio" */
342 for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
344 snprintf(prop_name, sizeof(prop_name), "%s-%s", con_id,
347 snprintf(prop_name, sizeof(prop_name), "%s",
350 desc = of_get_named_gpiod_flags(dev->of_node, prop_name, idx,
353 * -EPROBE_DEFER in our case means that we found a
354 * valid GPIO property, but no controller has been
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.
362 if (IS_ERR(desc) && PTR_ERR(desc) == -EPROBE_DEFER)
365 if (!IS_ERR(desc) || (PTR_ERR(desc) != -ENOENT))
369 /* Special handling for SPI GPIOs if used */
371 desc = of_find_spi_gpio(dev, con_id, &of_flags);
373 /* This quirk looks up flags and all */
374 desc = of_find_spi_cs_gpio(dev, con_id, idx, flags);
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);
386 if (of_flags & OF_GPIO_ACTIVE_LOW)
387 *flags |= GPIO_ACTIVE_LOW;
389 if (of_flags & OF_GPIO_SINGLE_ENDED) {
390 if (of_flags & OF_GPIO_OPEN_DRAIN)
391 *flags |= GPIO_OPEN_DRAIN;
393 *flags |= GPIO_OPEN_SOURCE;
396 if (of_flags & OF_GPIO_TRANSITORY)
397 *flags |= GPIO_TRANSITORY;
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;
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
417 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
418 * value on the error condition.
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)
426 struct device_node *chip_np;
427 enum of_gpio_flags xlate_flags;
428 struct of_phandle_args gpiospec;
429 struct gpio_desc *desc;
434 chip_np = chip->of_node;
436 return ERR_PTR(-EINVAL);
439 *lflags = GPIO_LOOKUP_FLAGS_DEFAULT;
442 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
446 gpiospec.np = chip_np;
447 gpiospec.args_count = tmp;
449 for (i = 0; i < tmp; i++) {
450 ret = of_property_read_u32_index(np, "gpios", idx * tmp + i,
456 desc = of_xlate_and_get_gpiod_flags(chip, &gpiospec, &xlate_flags);
460 if (xlate_flags & OF_GPIO_ACTIVE_LOW)
461 *lflags |= GPIO_ACTIVE_LOW;
462 if (xlate_flags & OF_GPIO_TRANSITORY)
463 *lflags |= GPIO_TRANSITORY;
465 if (of_property_read_bool(np, "input"))
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;
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);
477 if (name && of_property_read_string(np, "line-name", name))
484 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
485 * @chip: gpio chip to act on
487 * This is only used by of_gpiochip_add to request/set GPIO initial
489 * It returns error if it fails otherwise 0 on success.
491 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
493 struct gpio_desc *desc = NULL;
494 struct device_node *np;
496 unsigned long lflags;
497 enum gpiod_flags dflags;
501 for_each_available_child_of_node(chip->of_node, np) {
502 if (!of_property_read_bool(np, "gpio-hog"))
506 desc = of_parse_own_gpio(np, chip, i, &name, &lflags,
511 ret = gpiod_hog(desc, name, lflags, dflags);
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
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).
532 int of_gpio_simple_xlate(struct gpio_chip *gc,
533 const struct of_phandle_args *gpiospec, u32 *flags)
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).
541 if (gc->of_gpio_n_cells < 2) {
546 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
549 if (gpiospec->args[0] >= gc->ngpio)
553 *flags = gpiospec->args[1];
555 return gpiospec->args[0];
557 EXPORT_SYMBOL(of_gpio_simple_xlate);
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
565 * To use this function you should allocate and fill mm_gc with:
567 * 1) In the gpio_chip structure:
568 * - all the callbacks
570 * - of_xlate callback (optional)
572 * 3) In the of_mm_gpio_chip structure:
573 * - save_regs callback (optional)
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.
579 int of_mm_gpiochip_add_data(struct device_node *np,
580 struct of_mm_gpio_chip *mm_gc,
584 struct gpio_chip *gc = &mm_gc->gc;
586 gc->label = kasprintf(GFP_KERNEL, "%pOF", np);
590 mm_gc->regs = of_iomap(np, 0);
596 if (mm_gc->save_regs)
597 mm_gc->save_regs(mm_gc);
599 mm_gc->gc.of_node = np;
601 ret = gpiochip_add_data(gc, data);
607 iounmap(mm_gc->regs);
611 pr_err("%pOF: GPIO chip registration failed with status %d\n", np, ret);
614 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
617 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
618 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
620 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
622 struct gpio_chip *gc = &mm_gc->gc;
628 iounmap(mm_gc->regs);
631 EXPORT_SYMBOL(of_mm_gpiochip_remove);
633 static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
637 struct device_node *np = chip->of_node;
639 len = of_property_count_u32_elems(np, "gpio-reserved-ranges");
640 if (len < 0 || len % 2 != 0)
643 for (i = 0; i < len; i += 2) {
644 of_property_read_u32_index(np, "gpio-reserved-ranges",
646 of_property_read_u32_index(np, "gpio-reserved-ranges",
648 if (start >= chip->ngpio || start + count >= chip->ngpio)
651 bitmap_clear(chip->valid_mask, start, count);
655 #ifdef CONFIG_PINCTRL
656 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
658 struct device_node *np = chip->of_node;
659 struct of_phandle_args pinspec;
660 struct pinctrl_dev *pctldev;
663 static const char group_names_propname[] = "gpio-ranges-group-names";
664 struct property *group_names;
669 group_names = of_find_property(np, group_names_propname, NULL);
672 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
677 pctldev = of_pinctrl_get(pinspec.np);
678 of_node_put(pinspec.np);
680 return -EPROBE_DEFER;
682 if (pinspec.args[2]) {
684 of_property_read_string_index(np,
685 group_names_propname,
688 pr_err("%pOF: Group name of numeric GPIO ranges must be the empty string.\n",
693 /* npins != 0: linear range */
694 ret = gpiochip_add_pin_range(chip,
695 pinctrl_dev_get_devname(pctldev),
702 /* npins == 0: special range */
703 if (pinspec.args[1]) {
704 pr_err("%pOF: Illegal gpio-range format.\n",
710 pr_err("%pOF: GPIO group range requested but no %s property.\n",
711 np, group_names_propname);
715 ret = of_property_read_string_index(np,
716 group_names_propname,
722 pr_err("%pOF: Group name of GPIO group range cannot be the empty string.\n",
727 ret = gpiochip_add_pingroup_range(chip, pctldev,
728 pinspec.args[0], name);
738 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
741 int of_gpiochip_add(struct gpio_chip *chip)
748 if (!chip->of_xlate) {
749 chip->of_gpio_n_cells = 2;
750 chip->of_xlate = of_gpio_simple_xlate;
753 if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
756 of_gpiochip_init_valid_mask(chip);
758 status = of_gpiochip_add_pin_range(chip);
762 /* If the chip defines names itself, these take precedence */
764 devprop_gpiochip_set_names(chip,
765 of_fwnode_handle(chip->of_node));
767 of_node_get(chip->of_node);
769 status = of_gpiochip_scan_gpios(chip);
771 of_node_put(chip->of_node);
772 gpiochip_remove_pin_ranges(chip);
778 void of_gpiochip_remove(struct gpio_chip *chip)
780 gpiochip_remove_pin_ranges(chip);
781 of_node_put(chip->of_node);