x86: cache_info: Kill the atomic allocation in amd_init_l3_cache()
[linux-2.6/linux-mips.git] / drivers / of / gpio.c
blob905960338fb21d905a21153b7e8bcc3832ab691a
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_gpio_flags - Get a GPIO number and flags to use with GPIO API
25 * @np: device node to get GPIO from
26 * @index: index of the GPIO
27 * @flags: a flags pointer to fill in
29 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
30 * value on the error condition. If @flags is not NULL the function also fills
31 * in flags for the GPIO.
33 int of_get_gpio_flags(struct device_node *np, int index,
34 enum of_gpio_flags *flags)
36 int ret;
37 struct device_node *gpio_np;
38 struct gpio_chip *gc;
39 int size;
40 const void *gpio_spec;
41 const __be32 *gpio_cells;
43 ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index,
44 &gpio_np, &gpio_spec);
45 if (ret) {
46 pr_debug("%s: can't parse gpios property\n", __func__);
47 goto err0;
50 gc = of_node_to_gpiochip(gpio_np);
51 if (!gc) {
52 pr_debug("%s: gpio controller %s isn't registered\n",
53 np->full_name, gpio_np->full_name);
54 ret = -ENODEV;
55 goto err1;
58 gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size);
59 if (!gpio_cells || size != sizeof(*gpio_cells) ||
60 be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) {
61 pr_debug("%s: wrong #gpio-cells for %s\n",
62 np->full_name, gpio_np->full_name);
63 ret = -EINVAL;
64 goto err1;
67 /* .xlate might decide to not fill in the flags, so clear it. */
68 if (flags)
69 *flags = 0;
71 ret = gc->of_xlate(gc, np, gpio_spec, flags);
72 if (ret < 0)
73 goto err1;
75 ret += gc->base;
76 err1:
77 of_node_put(gpio_np);
78 err0:
79 pr_debug("%s exited with status %d\n", __func__, ret);
80 return ret;
82 EXPORT_SYMBOL(of_get_gpio_flags);
84 /**
85 * of_gpio_count - Count GPIOs for a device
86 * @np: device node to count GPIOs for
88 * The function returns the count of GPIOs specified for a node.
90 * Note that the empty GPIO specifiers counts too. For example,
92 * gpios = <0
93 * &pio1 1 2
94 * 0
95 * &pio2 3 4>;
97 * defines four GPIOs (so this function will return 4), two of which
98 * are not specified.
100 unsigned int of_gpio_count(struct device_node *np)
102 unsigned int cnt = 0;
104 do {
105 int ret;
107 ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells",
108 cnt, NULL, NULL);
109 /* A hole in the gpios = <> counts anyway. */
110 if (ret < 0 && ret != -EEXIST)
111 break;
112 } while (++cnt);
114 return cnt;
116 EXPORT_SYMBOL(of_gpio_count);
119 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
120 * @gc: pointer to the gpio_chip structure
121 * @np: device node of the GPIO chip
122 * @gpio_spec: gpio specifier as found in the device tree
123 * @flags: a flags pointer to fill in
125 * This is simple translation function, suitable for the most 1:1 mapped
126 * gpio chips. This function performs only one sanity check: whether gpio
127 * is less than ngpios (that is specified in the gpio_chip).
129 static int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
130 const void *gpio_spec, u32 *flags)
132 const __be32 *gpio = gpio_spec;
133 const u32 n = be32_to_cpup(gpio);
136 * We're discouraging gpio_cells < 2, since that way you'll have to
137 * write your own xlate function (that will have to retrive the GPIO
138 * number and the flags from a single gpio cell -- this is possible,
139 * but not recommended).
141 if (gc->of_gpio_n_cells < 2) {
142 WARN_ON(1);
143 return -EINVAL;
146 if (n > gc->ngpio)
147 return -EINVAL;
149 if (flags)
150 *flags = be32_to_cpu(gpio[1]);
152 return n;
156 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
157 * @np: device node of the GPIO chip
158 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
160 * To use this function you should allocate and fill mm_gc with:
162 * 1) In the gpio_chip structure:
163 * - all the callbacks
164 * - of_gpio_n_cells
165 * - of_xlate callback (optional)
167 * 3) In the of_mm_gpio_chip structure:
168 * - save_regs callback (optional)
170 * If succeeded, this function will map bank's memory and will
171 * do all necessary work for you. Then you'll able to use .regs
172 * to manage GPIOs from the callbacks.
174 int of_mm_gpiochip_add(struct device_node *np,
175 struct of_mm_gpio_chip *mm_gc)
177 int ret = -ENOMEM;
178 struct gpio_chip *gc = &mm_gc->gc;
180 gc->label = kstrdup(np->full_name, GFP_KERNEL);
181 if (!gc->label)
182 goto err0;
184 mm_gc->regs = of_iomap(np, 0);
185 if (!mm_gc->regs)
186 goto err1;
188 gc->base = -1;
190 if (mm_gc->save_regs)
191 mm_gc->save_regs(mm_gc);
193 mm_gc->gc.of_node = np;
195 ret = gpiochip_add(gc);
196 if (ret)
197 goto err2;
199 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
200 np->full_name, gc->base);
201 return 0;
202 err2:
203 iounmap(mm_gc->regs);
204 err1:
205 kfree(gc->label);
206 err0:
207 pr_err("%s: GPIO chip registration failed with status %d\n",
208 np->full_name, ret);
209 return ret;
211 EXPORT_SYMBOL(of_mm_gpiochip_add);
213 void of_gpiochip_add(struct gpio_chip *chip)
215 if ((!chip->of_node) && (chip->dev))
216 chip->of_node = chip->dev->of_node;
218 if (!chip->of_node)
219 return;
221 if (!chip->of_xlate) {
222 chip->of_gpio_n_cells = 2;
223 chip->of_xlate = of_gpio_simple_xlate;
226 of_node_get(chip->of_node);
229 void of_gpiochip_remove(struct gpio_chip *chip)
231 if (chip->of_node)
232 of_node_put(chip->of_node);
235 /* Private function for resolving node pointer to gpio_chip */
236 static int of_gpiochip_is_match(struct gpio_chip *chip, void *data)
238 return chip->of_node == data;
241 struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
243 return gpiochip_find(np, of_gpiochip_is_match);