freezer: don't unnecessarily set PF_NOFREEZE explicitly
[linux-2.6.git] / drivers / of / gpio.c
blobef0105fa52b14d1280e3fb746387d713cb0d7933
1 /*
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>
17 #include <linux/io.h>
18 #include <linux/of.h>
19 #include <linux/of_address.h>
20 #include <linux/of_gpio.h>
21 #include <linux/slab.h>
23 /**
24 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
25 * @np: device node to get GPIO from
26 * @propname: property name containing gpio specifier(s)
27 * @index: index of the GPIO
28 * @flags: a flags pointer to fill in
30 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
31 * value on the error condition. If @flags is not NULL the function also fills
32 * in flags for the GPIO.
34 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
35 int index, enum of_gpio_flags *flags)
37 int ret;
38 struct device_node *gpio_np;
39 struct gpio_chip *gc;
40 int size;
41 const void *gpio_spec;
42 const __be32 *gpio_cells;
44 ret = of_parse_phandles_with_args(np, propname, "#gpio-cells", index,
45 &gpio_np, &gpio_spec);
46 if (ret) {
47 pr_debug("%s: can't parse gpios property\n", __func__);
48 goto err0;
51 gc = of_node_to_gpiochip(gpio_np);
52 if (!gc) {
53 pr_debug("%s: gpio controller %s isn't registered\n",
54 np->full_name, gpio_np->full_name);
55 ret = -ENODEV;
56 goto err1;
59 gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size);
60 if (!gpio_cells || size != sizeof(*gpio_cells) ||
61 be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) {
62 pr_debug("%s: wrong #gpio-cells for %s\n",
63 np->full_name, gpio_np->full_name);
64 ret = -EINVAL;
65 goto err1;
68 /* .xlate might decide to not fill in the flags, so clear it. */
69 if (flags)
70 *flags = 0;
72 ret = gc->of_xlate(gc, np, gpio_spec, flags);
73 if (ret < 0)
74 goto err1;
76 ret += gc->base;
77 err1:
78 of_node_put(gpio_np);
79 err0:
80 pr_debug("%s exited with status %d\n", __func__, ret);
81 return ret;
83 EXPORT_SYMBOL(of_get_named_gpio_flags);
85 /**
86 * of_gpio_count - Count GPIOs for a device
87 * @np: device node to count GPIOs for
89 * The function returns the count of GPIOs specified for a node.
91 * Note that the empty GPIO specifiers counts too. For example,
93 * gpios = <0
94 * &pio1 1 2
95 * 0
96 * &pio2 3 4>;
98 * defines four GPIOs (so this function will return 4), two of which
99 * are not specified.
101 unsigned int of_gpio_count(struct device_node *np)
103 unsigned int cnt = 0;
105 do {
106 int ret;
108 ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells",
109 cnt, NULL, NULL);
110 /* A hole in the gpios = <> counts anyway. */
111 if (ret < 0 && ret != -EEXIST)
112 break;
113 } while (++cnt);
115 return cnt;
117 EXPORT_SYMBOL(of_gpio_count);
120 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
121 * @gc: pointer to the gpio_chip structure
122 * @np: device node of the GPIO chip
123 * @gpio_spec: gpio specifier as found in the device tree
124 * @flags: a flags pointer to fill in
126 * This is simple translation function, suitable for the most 1:1 mapped
127 * gpio chips. This function performs only one sanity check: whether gpio
128 * is less than ngpios (that is specified in the gpio_chip).
130 int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
131 const void *gpio_spec, u32 *flags)
133 const __be32 *gpio = gpio_spec;
134 const u32 n = be32_to_cpup(gpio);
137 * We're discouraging gpio_cells < 2, since that way you'll have to
138 * write your own xlate function (that will have to retrive the GPIO
139 * number and the flags from a single gpio cell -- this is possible,
140 * but not recommended).
142 if (gc->of_gpio_n_cells < 2) {
143 WARN_ON(1);
144 return -EINVAL;
147 if (n > gc->ngpio)
148 return -EINVAL;
150 if (flags)
151 *flags = be32_to_cpu(gpio[1]);
153 return n;
155 EXPORT_SYMBOL(of_gpio_simple_xlate);
158 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
159 * @np: device node of the GPIO chip
160 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
162 * To use this function you should allocate and fill mm_gc with:
164 * 1) In the gpio_chip structure:
165 * - all the callbacks
166 * - of_gpio_n_cells
167 * - of_xlate callback (optional)
169 * 3) In the of_mm_gpio_chip structure:
170 * - save_regs callback (optional)
172 * If succeeded, this function will map bank's memory and will
173 * do all necessary work for you. Then you'll able to use .regs
174 * to manage GPIOs from the callbacks.
176 int of_mm_gpiochip_add(struct device_node *np,
177 struct of_mm_gpio_chip *mm_gc)
179 int ret = -ENOMEM;
180 struct gpio_chip *gc = &mm_gc->gc;
182 gc->label = kstrdup(np->full_name, GFP_KERNEL);
183 if (!gc->label)
184 goto err0;
186 mm_gc->regs = of_iomap(np, 0);
187 if (!mm_gc->regs)
188 goto err1;
190 gc->base = -1;
192 if (mm_gc->save_regs)
193 mm_gc->save_regs(mm_gc);
195 mm_gc->gc.of_node = np;
197 ret = gpiochip_add(gc);
198 if (ret)
199 goto err2;
201 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
202 np->full_name, gc->base);
203 return 0;
204 err2:
205 iounmap(mm_gc->regs);
206 err1:
207 kfree(gc->label);
208 err0:
209 pr_err("%s: GPIO chip registration failed with status %d\n",
210 np->full_name, ret);
211 return ret;
213 EXPORT_SYMBOL(of_mm_gpiochip_add);
215 void of_gpiochip_add(struct gpio_chip *chip)
217 if ((!chip->of_node) && (chip->dev))
218 chip->of_node = chip->dev->of_node;
220 if (!chip->of_node)
221 return;
223 if (!chip->of_xlate) {
224 chip->of_gpio_n_cells = 2;
225 chip->of_xlate = of_gpio_simple_xlate;
228 of_node_get(chip->of_node);
231 void of_gpiochip_remove(struct gpio_chip *chip)
233 if (chip->of_node)
234 of_node_put(chip->of_node);
237 /* Private function for resolving node pointer to gpio_chip */
238 static int of_gpiochip_is_match(struct gpio_chip *chip, void *data)
240 return chip->of_node == data;
243 struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
245 return gpiochip_find(np, of_gpiochip_is_match);