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.h>
21 #include <linux/of_address.h>
22 #include <linux/of_gpio.h>
23 #include <linux/pinctrl/pinctrl.h>
24 #include <linux/slab.h>
26 /* Private data structure for of_gpiochip_find_and_xlate */
28 enum of_gpio_flags *flags;
29 struct of_phandle_args gpiospec;
34 /* Private function for resolving node pointer to gpio_chip */
35 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
37 struct gg_data *gg_data = data;
40 if ((gc->of_node != gg_data->gpiospec.np) ||
41 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
45 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
47 /* We've found the gpio chip, but the translation failed.
48 * Return true to stop looking and return the translation
51 gg_data->out_gpio = ERR_PTR(ret);
55 gg_data->out_gpio = ret + gc->base;
60 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
61 * @np: device node to get GPIO from
62 * @propname: property name containing gpio specifier(s)
63 * @index: index of the GPIO
64 * @flags: a flags pointer to fill in
66 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
67 * value on the error condition. If @flags is not NULL the function also fills
68 * in flags for the GPIO.
70 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
71 int index, enum of_gpio_flags *flags)
73 /* Return -EPROBE_DEFER to support probe() functions to be called
74 * later when the GPIO actually becomes available
76 struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER };
79 /* .of_xlate might decide to not fill in the flags, so clear it. */
83 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
86 pr_debug("%s: can't parse gpios property\n", __func__);
90 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
92 of_node_put(gg_data.gpiospec.np);
93 pr_debug("%s exited with status %d\n", __func__, gg_data.out_gpio);
94 return gg_data.out_gpio;
96 EXPORT_SYMBOL(of_get_named_gpio_flags);
99 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
100 * @gc: pointer to the gpio_chip structure
101 * @np: device node of the GPIO chip
102 * @gpio_spec: gpio specifier as found in the device tree
103 * @flags: a flags pointer to fill in
105 * This is simple translation function, suitable for the most 1:1 mapped
106 * gpio chips. This function performs only one sanity check: whether gpio
107 * is less than ngpios (that is specified in the gpio_chip).
109 int of_gpio_simple_xlate(struct gpio_chip *gc,
110 const struct of_phandle_args *gpiospec, u32 *flags)
113 * We're discouraging gpio_cells < 2, since that way you'll have to
114 * write your own xlate function (that will have to retrive the GPIO
115 * number and the flags from a single gpio cell -- this is possible,
116 * but not recommended).
118 if (gc->of_gpio_n_cells < 2) {
123 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
126 if (gpiospec->args[0] >= gc->ngpio)
130 *flags = gpiospec->args[1];
132 return gpiospec->args[0];
134 EXPORT_SYMBOL(of_gpio_simple_xlate);
137 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
138 * @np: device node of the GPIO chip
139 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
141 * To use this function you should allocate and fill mm_gc with:
143 * 1) In the gpio_chip structure:
144 * - all the callbacks
146 * - of_xlate callback (optional)
148 * 3) In the of_mm_gpio_chip structure:
149 * - save_regs callback (optional)
151 * If succeeded, this function will map bank's memory and will
152 * do all necessary work for you. Then you'll able to use .regs
153 * to manage GPIOs from the callbacks.
155 int of_mm_gpiochip_add(struct device_node *np,
156 struct of_mm_gpio_chip *mm_gc)
159 struct gpio_chip *gc = &mm_gc->gc;
161 gc->label = kstrdup(np->full_name, GFP_KERNEL);
165 mm_gc->regs = of_iomap(np, 0);
171 if (mm_gc->save_regs)
172 mm_gc->save_regs(mm_gc);
174 mm_gc->gc.of_node = np;
176 ret = gpiochip_add(gc);
182 iounmap(mm_gc->regs);
186 pr_err("%s: GPIO chip registration failed with status %d\n",
190 EXPORT_SYMBOL(of_mm_gpiochip_add);
192 #ifdef CONFIG_PINCTRL
193 static void of_gpiochip_add_pin_range(struct gpio_chip *chip)
195 struct device_node *np = chip->of_node;
196 struct of_phandle_args pinspec;
197 struct pinctrl_dev *pctldev;
204 ret = of_parse_phandle_with_args(np, "gpio-ranges",
205 "#gpio-range-cells", index, &pinspec);
209 pctldev = of_pinctrl_get(pinspec.np);
213 ret = gpiochip_add_pin_range(chip,
214 pinctrl_dev_get_devname(pctldev),
225 static void of_gpiochip_add_pin_range(struct gpio_chip *chip) {}
228 void of_gpiochip_add(struct gpio_chip *chip)
230 if ((!chip->of_node) && (chip->dev))
231 chip->of_node = chip->dev->of_node;
236 if (!chip->of_xlate) {
237 chip->of_gpio_n_cells = 2;
238 chip->of_xlate = of_gpio_simple_xlate;
241 of_gpiochip_add_pin_range(chip);
242 of_node_get(chip->of_node);
245 void of_gpiochip_remove(struct gpio_chip *chip)
247 gpiochip_remove_pin_ranges(chip);
250 of_node_put(chip->of_node);