serial: xilinx_uartps: fix bad register write in console_write
[linux-2.6-xlnx.git] / drivers / gpio / gpiolib-of.c
blobd18068a9f3ecf18aaf0a0106ca7c1b4c752d25c9
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/gpio.h>
19 #include <linux/of.h>
20 #include <linux/of_address.h>
21 #include <linux/of_gpio.h>
22 #include <linux/slab.h>
24 /* Private data structure for of_gpiochip_is_match */
25 struct gg_data {
26 enum of_gpio_flags *flags;
27 struct of_phandle_args gpiospec;
29 int out_gpio;
32 /* Private function for resolving node pointer to gpio_chip */
33 static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
35 struct gg_data *gg_data = data;
36 int ret;
38 if ((gc->of_node != gg_data->gpiospec.np) ||
39 (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
40 (!gc->of_xlate))
41 return false;
43 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
44 if (ret < 0)
45 return false;
47 gg_data->out_gpio = ret + gc->base;
48 return true;
51 /**
52 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
53 * @np: device node to get GPIO from
54 * @propname: property name containing gpio specifier(s)
55 * @index: index of the GPIO
56 * @flags: a flags pointer to fill in
58 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
59 * value on the error condition. If @flags is not NULL the function also fills
60 * in flags for the GPIO.
62 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
63 int index, enum of_gpio_flags *flags)
65 struct gg_data gg_data = { .flags = flags, .out_gpio = -ENODEV };
66 int ret;
68 /* .of_xlate might decide to not fill in the flags, so clear it. */
69 if (flags)
70 *flags = 0;
72 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
73 &gg_data.gpiospec);
74 if (ret) {
75 pr_debug("%s: can't parse gpios property\n", __func__);
76 return -EINVAL;
79 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
81 of_node_put(gg_data.gpiospec.np);
82 pr_debug("%s exited with status %d\n", __func__, ret);
83 return gg_data.out_gpio;
85 EXPORT_SYMBOL(of_get_named_gpio_flags);
87 /**
88 * of_gpio_named_count - Count GPIOs for a device
89 * @np: device node to count GPIOs for
90 * @propname: property name containing gpio specifier(s)
92 * The function returns the count of GPIOs specified for a node.
94 * Note that the empty GPIO specifiers counts too. For example,
96 * gpios = <0
97 * &pio1 1 2
98 * 0
99 * &pio2 3 4>;
101 * defines four GPIOs (so this function will return 4), two of which
102 * are not specified.
104 unsigned int of_gpio_named_count(struct device_node *np, const char* propname)
106 unsigned int cnt = 0;
108 do {
109 int ret;
111 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
112 cnt, NULL);
113 /* A hole in the gpios = <> counts anyway. */
114 if (ret < 0 && ret != -EEXIST)
115 break;
116 } while (++cnt);
118 return cnt;
120 EXPORT_SYMBOL(of_gpio_named_count);
123 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
124 * @gc: pointer to the gpio_chip structure
125 * @np: device node of the GPIO chip
126 * @gpio_spec: gpio specifier as found in the device tree
127 * @flags: a flags pointer to fill in
129 * This is simple translation function, suitable for the most 1:1 mapped
130 * gpio chips. This function performs only one sanity check: whether gpio
131 * is less than ngpios (that is specified in the gpio_chip).
133 int of_gpio_simple_xlate(struct gpio_chip *gc,
134 const struct of_phandle_args *gpiospec, u32 *flags)
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 (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
148 return -EINVAL;
150 if (gpiospec->args[0] >= gc->ngpio)
151 return -EINVAL;
153 if (flags)
154 *flags = gpiospec->args[1];
156 return gpiospec->args[0];
158 EXPORT_SYMBOL(of_gpio_simple_xlate);
161 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
162 * @np: device node of the GPIO chip
163 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
165 * To use this function you should allocate and fill mm_gc with:
167 * 1) In the gpio_chip structure:
168 * - all the callbacks
169 * - of_gpio_n_cells
170 * - of_xlate callback (optional)
172 * 3) In the of_mm_gpio_chip structure:
173 * - save_regs callback (optional)
175 * If succeeded, this function will map bank's memory and will
176 * do all necessary work for you. Then you'll able to use .regs
177 * to manage GPIOs from the callbacks.
179 int of_mm_gpiochip_add(struct device_node *np,
180 struct of_mm_gpio_chip *mm_gc)
182 int ret = -ENOMEM;
183 struct gpio_chip *gc = &mm_gc->gc;
185 gc->label = kstrdup(np->full_name, GFP_KERNEL);
186 if (!gc->label)
187 goto err0;
189 mm_gc->regs = of_iomap(np, 0);
190 if (!mm_gc->regs)
191 goto err1;
193 gc->base = -1;
195 if (mm_gc->save_regs)
196 mm_gc->save_regs(mm_gc);
198 mm_gc->gc.of_node = np;
200 ret = gpiochip_add(gc);
201 if (ret)
202 goto err2;
204 return 0;
205 err2:
206 iounmap(mm_gc->regs);
207 err1:
208 kfree(gc->label);
209 err0:
210 pr_err("%s: GPIO chip registration failed with status %d\n",
211 np->full_name, ret);
212 return ret;
214 EXPORT_SYMBOL(of_mm_gpiochip_add);
216 void of_gpiochip_add(struct gpio_chip *chip)
218 if ((!chip->of_node) && (chip->dev))
219 chip->of_node = chip->dev->of_node;
221 if (!chip->of_node)
222 return;
224 if (!chip->of_xlate) {
225 chip->of_gpio_n_cells = 2;
226 chip->of_xlate = of_gpio_simple_xlate;
229 of_node_get(chip->of_node);
232 void of_gpiochip_remove(struct gpio_chip *chip)
234 if (chip->of_node)
235 of_node_put(chip->of_node);