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/errno.h>
16 #include <linux/module.h>
18 #include <linux/gpio.h>
20 #include <linux/of_address.h>
21 #include <linux/of_gpio.h>
22 #include <linux/pinctrl/pinctrl.h>
23 #include <linux/slab.h>
25 /* Private data structure for of_gpiochip_find_and_xlate */
27 enum of_gpio_flags *flags;
28 struct of_phandle_args gpiospec;
33 /* Private function for resolving node pointer to gpio_chip */
34 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
36 struct gg_data *gg_data = data;
39 if ((gc->of_node != gg_data->gpiospec.np) ||
40 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
44 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
48 gg_data->out_gpio = ret + gc->base;
53 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
54 * @np: device node to get GPIO from
55 * @propname: property name containing gpio specifier(s)
56 * @index: index of the GPIO
57 * @flags: a flags pointer to fill in
59 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
60 * value on the error condition. If @flags is not NULL the function also fills
61 * in flags for the GPIO.
63 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
64 int index, enum of_gpio_flags *flags)
66 /* Return -EPROBE_DEFER to support probe() functions to be called
67 * later when the GPIO actually becomes available
69 struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER };
72 /* .of_xlate might decide to not fill in the flags, so clear it. */
76 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
79 pr_debug("%s: can't parse gpios property\n", __func__);
83 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
85 of_node_put(gg_data.gpiospec.np);
86 pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio);
87 return gg_data.out_gpio;
89 EXPORT_SYMBOL(of_get_named_gpio_flags);
92 * of_gpio_named_count - Count GPIOs for a device
93 * @np: device node to count GPIOs for
94 * @propname: property name containing gpio specifier(s)
96 * The function returns the count of GPIOs specified for a node.
98 * Note that the empty GPIO specifiers counts too. For example,
105 * defines four GPIOs (so this function will return 4), two of which
108 unsigned int of_gpio_named_count(struct device_node *np, const char* propname)
110 unsigned int cnt = 0;
115 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
117 /* A hole in the gpios = <> counts anyway. */
118 if (ret < 0 && ret != -EEXIST)
124 EXPORT_SYMBOL(of_gpio_named_count);
127 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
128 * @gc: pointer to the gpio_chip structure
129 * @np: device node of the GPIO chip
130 * @gpio_spec: gpio specifier as found in the device tree
131 * @flags: a flags pointer to fill in
133 * This is simple translation function, suitable for the most 1:1 mapped
134 * gpio chips. This function performs only one sanity check: whether gpio
135 * is less than ngpios (that is specified in the gpio_chip).
137 int of_gpio_simple_xlate(struct gpio_chip *gc,
138 const struct of_phandle_args *gpiospec, u32 *flags)
141 * We're discouraging gpio_cells < 2, since that way you'll have to
142 * write your own xlate function (that will have to retrive the GPIO
143 * number and the flags from a single gpio cell -- this is possible,
144 * but not recommended).
146 if (gc->of_gpio_n_cells < 2) {
151 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
154 if (gpiospec->args[0] >= gc->ngpio)
158 *flags = gpiospec->args[1];
160 return gpiospec->args[0];
162 EXPORT_SYMBOL(of_gpio_simple_xlate);
165 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
166 * @np: device node of the GPIO chip
167 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
169 * To use this function you should allocate and fill mm_gc with:
171 * 1) In the gpio_chip structure:
172 * - all the callbacks
174 * - of_xlate callback (optional)
176 * 3) In the of_mm_gpio_chip structure:
177 * - save_regs callback (optional)
179 * If succeeded, this function will map bank's memory and will
180 * do all necessary work for you. Then you'll able to use .regs
181 * to manage GPIOs from the callbacks.
183 int of_mm_gpiochip_add(struct device_node *np,
184 struct of_mm_gpio_chip *mm_gc)
187 struct gpio_chip *gc = &mm_gc->gc;
189 gc->label = kstrdup(np->full_name, GFP_KERNEL);
193 mm_gc->regs = of_iomap(np, 0);
199 if (mm_gc->save_regs)
200 mm_gc->save_regs(mm_gc);
202 mm_gc->gc.of_node = np;
204 ret = gpiochip_add(gc);
210 iounmap(mm_gc->regs);
214 pr_err("%s: GPIO chip registration failed with status %d\n",
218 EXPORT_SYMBOL(of_mm_gpiochip_add);
220 #ifdef CONFIG_PINCTRL
221 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
223 struct device_node *np = chip->of_node;
224 struct of_phandle_args pinspec;
225 struct pinctrl_dev *pctldev;
232 ret = of_parse_phandle_with_args(np, "gpio-ranges",
233 "#gpio-range-cells", index, &pinspec);
237 pctldev = of_pinctrl_get(pinspec.np);
242 * This assumes that the n GPIO pins are consecutive in the
243 * GPIO number space, and that the pins are also consecutive
244 * in their local number space. Currently it is not possible
245 * to add different ranges for one and the same GPIO chip,
246 * as the code assumes that we have one consecutive range
247 * on both, mapping 1-to-1.
249 * TODO: make the OF bindings handle multiple sparse ranges
250 * on the same GPIO chip.
252 ret = gpiochip_add_pin_range(chip,
253 pinctrl_dev_get_name(pctldev),
254 0, /* offset in gpiochip */
265 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
268 void of_gpiochip_add(struct gpio_chip *chip)
270 if ((!chip->of_node) && (chip->dev))
271 chip->of_node = chip->dev->of_node;
276 if (!chip->of_xlate) {
277 chip->of_gpio_n_cells = 2;
278 chip->of_xlate = of_gpio_simple_xlate;
281 of_gpiochip_add_pin_range(chip);
282 of_node_get(chip->of_node);
285 void of_gpiochip_remove(struct gpio_chip *chip)
287 gpiochip_remove_pin_ranges(chip);
290 of_node_put(chip->of_node);