2 * OF helpers for the GPIO API
4 * Copyright (c) 2007-2008 MontaVista Software, Inc.
6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
14 #include <linux/device.h>
15 #include <linux/err.h>
16 #include <linux/errno.h>
17 #include <linux/module.h>
19 #include <linux/io-mapping.h>
20 #include <linux/gpio/consumer.h>
22 #include <linux/of_address.h>
23 #include <linux/of_gpio.h>
24 #include <linux/pinctrl/pinctrl.h>
25 #include <linux/slab.h>
26 #include <linux/gpio/machine.h>
30 /* Private data structure for of_gpiochip_find_and_xlate */
32 enum of_gpio_flags *flags;
33 struct of_phandle_args gpiospec;
35 struct gpio_desc *out_gpio;
38 /* Private function for resolving node pointer to gpio_chip */
39 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
41 struct gg_data *gg_data = data;
44 if ((gc->of_node != gg_data->gpiospec.np) ||
45 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
49 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
51 /* We've found a gpio chip, but the translation failed.
52 * Store translation error in out_gpio.
53 * Return false to keep looking, as more than one gpio chip
54 * could be registered per of-node.
56 gg_data->out_gpio = ERR_PTR(ret);
60 gg_data->out_gpio = gpiochip_get_desc(gc, ret);
65 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
66 * @np: device node to get GPIO from
67 * @propname: property name containing gpio specifier(s)
68 * @index: index of the GPIO
69 * @flags: a flags pointer to fill in
71 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
72 * value on the error condition. If @flags is not NULL the function also fills
73 * in flags for the GPIO.
75 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
76 const char *propname, int index, enum of_gpio_flags *flags)
78 /* Return -EPROBE_DEFER to support probe() functions to be called
79 * later when the GPIO actually becomes available
81 struct gg_data gg_data = {
83 .out_gpio = ERR_PTR(-EPROBE_DEFER)
87 /* .of_xlate might decide to not fill in the flags, so clear it. */
91 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
94 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
95 __func__, propname, np->full_name, index);
99 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
101 of_node_put(gg_data.gpiospec.np);
102 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
103 __func__, propname, np->full_name, index,
104 PTR_ERR_OR_ZERO(gg_data.out_gpio));
105 return gg_data.out_gpio;
108 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
109 int index, enum of_gpio_flags *flags)
111 struct gpio_desc *desc;
113 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
116 return PTR_ERR(desc);
118 return desc_to_gpio(desc);
120 EXPORT_SYMBOL(of_get_named_gpio_flags);
123 * of_parse_own_gpio() - Get a GPIO hog descriptor, names and flags for GPIO API
124 * @np: device node to get GPIO from
125 * @name: GPIO line name
126 * @lflags: gpio_lookup_flags - returned from of_find_gpio() or
127 * of_parse_own_gpio()
128 * @dflags: gpiod_flags - optional GPIO initialization flags
130 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
131 * value on the error condition.
133 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
135 enum gpio_lookup_flags *lflags,
136 enum gpiod_flags *dflags)
138 struct device_node *chip_np;
139 enum of_gpio_flags xlate_flags;
140 struct gg_data gg_data = {
141 .flags = &xlate_flags,
146 chip_np = np->parent;
148 return ERR_PTR(-EINVAL);
154 ret = of_property_read_u32(chip_np, "#gpio-cells", &tmp);
158 if (tmp > MAX_PHANDLE_ARGS)
159 return ERR_PTR(-EINVAL);
161 gg_data.gpiospec.args_count = tmp;
162 gg_data.gpiospec.np = chip_np;
163 for (i = 0; i < tmp; i++) {
164 ret = of_property_read_u32_index(np, "gpios", i,
165 &gg_data.gpiospec.args[i]);
170 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
171 if (!gg_data.out_gpio) {
172 if (np->parent == np)
173 return ERR_PTR(-ENXIO);
175 return ERR_PTR(-EINVAL);
178 if (xlate_flags & OF_GPIO_ACTIVE_LOW)
179 *lflags |= GPIO_ACTIVE_LOW;
181 if (of_property_read_bool(np, "input"))
183 else if (of_property_read_bool(np, "output-low"))
184 *dflags |= GPIOD_OUT_LOW;
185 else if (of_property_read_bool(np, "output-high"))
186 *dflags |= GPIOD_OUT_HIGH;
188 pr_warn("GPIO line %d (%s): no hogging state specified, bailing out\n",
189 desc_to_gpio(gg_data.out_gpio), np->name);
190 return ERR_PTR(-EINVAL);
193 if (name && of_property_read_string(np, "line-name", name))
196 return gg_data.out_gpio;
200 * of_gpiochip_set_names() - set up the names of the lines
201 * @chip: GPIO chip whose lines should be named, if possible
203 static void of_gpiochip_set_names(struct gpio_chip *gc)
205 struct gpio_device *gdev = gc->gpiodev;
206 struct device_node *np = gc->of_node;
210 nstrings = of_property_count_strings(np, "gpio-line-names");
212 /* Lines names not present */
215 /* This is normally not what you want */
216 if (gdev->ngpio != nstrings)
217 dev_info(&gdev->dev, "gpio-line-names specifies %d line "
218 "names but there are %d lines on the chip\n",
219 nstrings, gdev->ngpio);
222 * Make sure to not index beyond the end of the number of descriptors
223 * of the GPIO device.
225 for (i = 0; i < gdev->ngpio; i++) {
229 ret = of_property_read_string_index(np,
236 "unable to name line %d: %d\n",
240 gdev->descs[i].name = name;
245 * of_gpiochip_scan_gpios - Scan gpio-controller for gpio definitions
246 * @chip: gpio chip to act on
248 * This is only used by of_gpiochip_add to request/set GPIO initial
250 * It retures error if it fails otherwise 0 on success.
252 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
254 struct gpio_desc *desc = NULL;
255 struct device_node *np;
257 enum gpio_lookup_flags lflags;
258 enum gpiod_flags dflags;
261 for_each_available_child_of_node(chip->of_node, np) {
262 if (!of_property_read_bool(np, "gpio-hog"))
265 desc = of_parse_own_gpio(np, &name, &lflags, &dflags);
269 ret = gpiod_hog(desc, name, lflags, dflags);
278 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
279 * @gc: pointer to the gpio_chip structure
280 * @np: device node of the GPIO chip
281 * @gpio_spec: gpio specifier as found in the device tree
282 * @flags: a flags pointer to fill in
284 * This is simple translation function, suitable for the most 1:1 mapped
285 * gpio chips. This function performs only one sanity check: whether gpio
286 * is less than ngpios (that is specified in the gpio_chip).
288 int of_gpio_simple_xlate(struct gpio_chip *gc,
289 const struct of_phandle_args *gpiospec, u32 *flags)
292 * We're discouraging gpio_cells < 2, since that way you'll have to
293 * write your own xlate function (that will have to retrieve the GPIO
294 * number and the flags from a single gpio cell -- this is possible,
295 * but not recommended).
297 if (gc->of_gpio_n_cells < 2) {
302 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
305 if (gpiospec->args[0] >= gc->ngpio)
309 *flags = gpiospec->args[1];
311 return gpiospec->args[0];
313 EXPORT_SYMBOL(of_gpio_simple_xlate);
316 * of_mm_gpiochip_add_data - Add memory mapped GPIO chip (bank)
317 * @np: device node of the GPIO chip
318 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
319 * @data: driver data to store in the struct gpio_chip
321 * To use this function you should allocate and fill mm_gc with:
323 * 1) In the gpio_chip structure:
324 * - all the callbacks
326 * - of_xlate callback (optional)
328 * 3) In the of_mm_gpio_chip structure:
329 * - save_regs callback (optional)
331 * If succeeded, this function will map bank's memory and will
332 * do all necessary work for you. Then you'll able to use .regs
333 * to manage GPIOs from the callbacks.
335 int of_mm_gpiochip_add_data(struct device_node *np,
336 struct of_mm_gpio_chip *mm_gc,
340 struct gpio_chip *gc = &mm_gc->gc;
342 gc->label = kstrdup(np->full_name, GFP_KERNEL);
346 mm_gc->regs = of_iomap(np, 0);
352 if (mm_gc->save_regs)
353 mm_gc->save_regs(mm_gc);
355 mm_gc->gc.of_node = np;
357 ret = gpiochip_add_data(gc, data);
363 iounmap(mm_gc->regs);
367 pr_err("%s: GPIO chip registration failed with status %d\n",
371 EXPORT_SYMBOL(of_mm_gpiochip_add_data);
374 * of_mm_gpiochip_remove - Remove memory mapped GPIO chip (bank)
375 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
377 void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
379 struct gpio_chip *gc = &mm_gc->gc;
385 iounmap(mm_gc->regs);
388 EXPORT_SYMBOL(of_mm_gpiochip_remove);
390 #ifdef CONFIG_PINCTRL
391 static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
393 struct device_node *np = chip->of_node;
394 struct of_phandle_args pinspec;
395 struct pinctrl_dev *pctldev;
398 static const char group_names_propname[] = "gpio-ranges-group-names";
399 struct property *group_names;
404 group_names = of_find_property(np, group_names_propname, NULL);
407 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
412 pctldev = of_pinctrl_get(pinspec.np);
414 return -EPROBE_DEFER;
416 if (pinspec.args[2]) {
418 of_property_read_string_index(np,
419 group_names_propname,
422 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
427 /* npins != 0: linear range */
428 ret = gpiochip_add_pin_range(chip,
429 pinctrl_dev_get_devname(pctldev),
436 /* npins == 0: special range */
437 if (pinspec.args[1]) {
438 pr_err("%s: Illegal gpio-range format.\n",
444 pr_err("%s: GPIO group range requested but no %s property.\n",
445 np->full_name, group_names_propname);
449 ret = of_property_read_string_index(np,
450 group_names_propname,
456 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
461 ret = gpiochip_add_pingroup_range(chip, pctldev,
462 pinspec.args[0], name);
472 static int of_gpiochip_add_pin_range(struct gpio_chip *chip) { return 0; }
475 int of_gpiochip_add(struct gpio_chip *chip)
479 if ((!chip->of_node) && (chip->parent))
480 chip->of_node = chip->parent->of_node;
485 if (!chip->of_xlate) {
486 chip->of_gpio_n_cells = 2;
487 chip->of_xlate = of_gpio_simple_xlate;
490 status = of_gpiochip_add_pin_range(chip);
494 /* If the chip defines names itself, these take precedence */
496 of_gpiochip_set_names(chip);
498 of_node_get(chip->of_node);
500 return of_gpiochip_scan_gpios(chip);
503 void of_gpiochip_remove(struct gpio_chip *chip)
505 gpiochip_remove_pin_ranges(chip);
506 of_node_put(chip->of_node);