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/gpio/consumer.h>
21 #include <linux/of_address.h>
22 #include <linux/of_gpio.h>
23 #include <linux/pinctrl/pinctrl.h>
24 #include <linux/slab.h>
28 /* Private data structure for of_gpiochip_find_and_xlate */
30 enum of_gpio_flags *flags;
31 struct of_phandle_args gpiospec;
33 struct gpio_desc *out_gpio;
36 /* Private function for resolving node pointer to gpio_chip */
37 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
39 struct gg_data *gg_data = data;
42 if ((gc->of_node != gg_data->gpiospec.np) ||
43 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
47 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
51 gg_data->out_gpio = gpiochip_get_desc(gc, ret);
56 * of_get_named_gpiod_flags() - Get a GPIO descriptor and flags for GPIO API
57 * @np: device node to get GPIO from
58 * @propname: property name containing gpio specifier(s)
59 * @index: index of the GPIO
60 * @flags: a flags pointer to fill in
62 * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
63 * value on the error condition. If @flags is not NULL the function also fills
64 * in flags for the GPIO.
66 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
67 const char *propname, int index, enum of_gpio_flags *flags)
69 /* Return -EPROBE_DEFER to support probe() functions to be called
70 * later when the GPIO actually becomes available
72 struct gg_data gg_data = {
74 .out_gpio = ERR_PTR(-EPROBE_DEFER)
78 /* .of_xlate might decide to not fill in the flags, so clear it. */
82 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
85 pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
86 __func__, propname, np->full_name, index);
90 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
92 of_node_put(gg_data.gpiospec.np);
93 pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
94 __func__, propname, np->full_name, index,
95 PTR_ERR_OR_ZERO(gg_data.out_gpio));
96 return gg_data.out_gpio;
98 EXPORT_SYMBOL(of_get_named_gpiod_flags);
100 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,
101 int index, enum of_gpio_flags *flags)
103 struct gpio_desc *desc;
105 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
108 return PTR_ERR(desc);
110 return desc_to_gpio(desc);
112 EXPORT_SYMBOL(of_get_named_gpio_flags);
115 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
116 * @gc: pointer to the gpio_chip structure
117 * @np: device node of the GPIO chip
118 * @gpio_spec: gpio specifier as found in the device tree
119 * @flags: a flags pointer to fill in
121 * This is simple translation function, suitable for the most 1:1 mapped
122 * gpio chips. This function performs only one sanity check: whether gpio
123 * is less than ngpios (that is specified in the gpio_chip).
125 int of_gpio_simple_xlate(struct gpio_chip *gc,
126 const struct of_phandle_args *gpiospec, u32 *flags)
129 * We're discouraging gpio_cells < 2, since that way you'll have to
130 * write your own xlate function (that will have to retrive the GPIO
131 * number and the flags from a single gpio cell -- this is possible,
132 * but not recommended).
134 if (gc->of_gpio_n_cells < 2) {
139 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
142 if (gpiospec->args[0] >= gc->ngpio)
146 *flags = gpiospec->args[1];
148 return gpiospec->args[0];
150 EXPORT_SYMBOL(of_gpio_simple_xlate);
153 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
154 * @np: device node of the GPIO chip
155 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
157 * To use this function you should allocate and fill mm_gc with:
159 * 1) In the gpio_chip structure:
160 * - all the callbacks
162 * - of_xlate callback (optional)
164 * 3) In the of_mm_gpio_chip structure:
165 * - save_regs callback (optional)
167 * If succeeded, this function will map bank's memory and will
168 * do all necessary work for you. Then you'll able to use .regs
169 * to manage GPIOs from the callbacks.
171 int of_mm_gpiochip_add(struct device_node *np,
172 struct of_mm_gpio_chip *mm_gc)
175 struct gpio_chip *gc = &mm_gc->gc;
177 gc->label = kstrdup(np->full_name, GFP_KERNEL);
181 mm_gc->regs = of_iomap(np, 0);
187 if (mm_gc->save_regs)
188 mm_gc->save_regs(mm_gc);
190 mm_gc->gc.of_node = np;
192 ret = gpiochip_add(gc);
198 iounmap(mm_gc->regs);
202 pr_err("%s: GPIO chip registration failed with status %d\n",
206 EXPORT_SYMBOL(of_mm_gpiochip_add);
208 #ifdef CONFIG_PINCTRL
209 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
211 struct device_node *np = chip->of_node;
212 struct of_phandle_args pinspec;
213 struct pinctrl_dev *pctldev;
216 static const char group_names_propname[] = "gpio-ranges-group-names";
217 struct property *group_names;
222 group_names = of_find_property(np, group_names_propname, NULL);
225 ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3,
230 pctldev = of_pinctrl_get(pinspec.np);
234 if (pinspec.args[2]) {
236 ret = of_property_read_string_index(np,
237 group_names_propname,
240 pr_err("%s: Group name of numeric GPIO ranges must be the empty string.\n",
245 /* npins != 0: linear range */
246 ret = gpiochip_add_pin_range(chip,
247 pinctrl_dev_get_devname(pctldev),
254 /* npins == 0: special range */
255 if (pinspec.args[1]) {
256 pr_err("%s: Illegal gpio-range format.\n",
262 pr_err("%s: GPIO group range requested but no %s property.\n",
263 np->full_name, group_names_propname);
267 ret = of_property_read_string_index(np,
268 group_names_propname,
274 pr_err("%s: Group name of GPIO group range cannot be the empty string.\n",
279 ret = gpiochip_add_pingroup_range(chip, pctldev,
280 pinspec.args[0], name);
288 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
291 void of_gpiochip_add(struct gpio_chip *chip)
293 if ((!chip->of_node) && (chip->dev))
294 chip->of_node = chip->dev->of_node;
299 if (!chip->of_xlate) {
300 chip->of_gpio_n_cells = 2;
301 chip->of_xlate = of_gpio_simple_xlate;
304 of_gpiochip_add_pin_range(chip);
305 of_node_get(chip->of_node);
308 void of_gpiochip_remove(struct gpio_chip *chip)
310 gpiochip_remove_pin_ranges(chip);
313 of_node_put(chip->of_node);