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Anton Vorontsov863fbf42008-04-11 23:06:45 +10001/*
2 * OF helpers for the GPIO API
3 *
4 * Copyright (c) 2007-2008 MontaVista Software, Inc.
5 *
6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
7 *
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.
12 */
13
Grant Likely2e13cba2010-07-05 16:11:55 -060014#include <linux/device.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100015#include <linux/errno.h>
Grant Likely2e13cba2010-07-05 16:11:55 -060016#include <linux/module.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100017#include <linux/io.h>
Grant Likely3d0f7cf2012-05-17 13:54:40 -060018#include <linux/gpio.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100019#include <linux/of.h>
Grant Likely2e13cba2010-07-05 16:11:55 -060020#include <linux/of_address.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100021#include <linux/of_gpio.h>
Grant Likely2e13cba2010-07-05 16:11:55 -060022#include <linux/slab.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100023
Dong Aisheng0df2c992012-05-25 21:36:15 +080024/* Private data structure for of_gpiochip_find_and_xlate */
Grant Likely3d0f7cf2012-05-17 13:54:40 -060025struct gg_data {
26 enum of_gpio_flags *flags;
27 struct of_phandle_args gpiospec;
28
29 int out_gpio;
30};
31
32/* Private function for resolving node pointer to gpio_chip */
33static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
34{
35 struct gg_data *gg_data = data;
36 int ret;
37
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;
42
43 ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
44 if (ret < 0)
45 return false;
46
47 gg_data->out_gpio = ret + gc->base;
48 return true;
49}
50
Anton Vorontsov863fbf42008-04-11 23:06:45 +100051/**
John Bonesioa6b09192011-06-27 16:49:57 -070052 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
Anton Vorontsov863fbf42008-04-11 23:06:45 +100053 * @np: device node to get GPIO from
John Bonesioa6b09192011-06-27 16:49:57 -070054 * @propname: property name containing gpio specifier(s)
Anton Vorontsov863fbf42008-04-11 23:06:45 +100055 * @index: index of the GPIO
Anton Vorontsovb908b532008-12-01 06:30:04 +000056 * @flags: a flags pointer to fill in
Anton Vorontsov863fbf42008-04-11 23:06:45 +100057 *
58 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
Anton Vorontsovb908b532008-12-01 06:30:04 +000059 * value on the error condition. If @flags is not NULL the function also fills
60 * in flags for the GPIO.
Anton Vorontsov863fbf42008-04-11 23:06:45 +100061 */
John Bonesioa6b09192011-06-27 16:49:57 -070062int of_get_named_gpio_flags(struct device_node *np, const char *propname,
63 int index, enum of_gpio_flags *flags)
Anton Vorontsov863fbf42008-04-11 23:06:45 +100064{
Roland Stigge4fbb0022012-06-28 00:32:14 +020065 /* Return -EPROBE_DEFER to support probe() functions to be called
66 * later when the GPIO actually becomes available
67 */
68 struct gg_data gg_data = { .flags = flags, .out_gpio = -EPROBE_DEFER };
Anton Vorontsov64b60e02008-10-10 04:43:17 +000069 int ret;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100070
Grant Likely3d0f7cf2012-05-17 13:54:40 -060071 /* .of_xlate might decide to not fill in the flags, so clear it. */
Anton Vorontsovb908b532008-12-01 06:30:04 +000072 if (flags)
73 *flags = 0;
74
Grant Likely3d0f7cf2012-05-17 13:54:40 -060075 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
76 &gg_data.gpiospec);
77 if (ret) {
78 pr_debug("%s: can't parse gpios property\n", __func__);
Alexandre Courbot41920d162012-06-29 13:57:59 +090079 return ret;
Grant Likely3d0f7cf2012-05-17 13:54:40 -060080 }
Anton Vorontsov863fbf42008-04-11 23:06:45 +100081
Grant Likely3d0f7cf2012-05-17 13:54:40 -060082 gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
83
84 of_node_put(gg_data.gpiospec.np);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100085 pr_debug("%s exited with status %d\n", __func__, ret);
Grant Likely3d0f7cf2012-05-17 13:54:40 -060086 return gg_data.out_gpio;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100087}
John Bonesioa6b09192011-06-27 16:49:57 -070088EXPORT_SYMBOL(of_get_named_gpio_flags);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100089
90/**
Jean-Christophe PLAGNIOL-VILLARDff64abe2012-02-02 16:20:01 +010091 * of_gpio_named_count - Count GPIOs for a device
Anton Vorontsov74982092008-12-05 08:15:54 +000092 * @np: device node to count GPIOs for
Jean-Christophe PLAGNIOL-VILLARDff64abe2012-02-02 16:20:01 +010093 * @propname: property name containing gpio specifier(s)
Anton Vorontsov74982092008-12-05 08:15:54 +000094 *
95 * The function returns the count of GPIOs specified for a node.
96 *
97 * Note that the empty GPIO specifiers counts too. For example,
98 *
99 * gpios = <0
100 * &pio1 1 2
101 * 0
102 * &pio2 3 4>;
103 *
104 * defines four GPIOs (so this function will return 4), two of which
105 * are not specified.
106 */
Jean-Christophe PLAGNIOL-VILLARDff64abe2012-02-02 16:20:01 +0100107unsigned int of_gpio_named_count(struct device_node *np, const char* propname)
Anton Vorontsov74982092008-12-05 08:15:54 +0000108{
109 unsigned int cnt = 0;
110
111 do {
112 int ret;
113
Jean-Christophe PLAGNIOL-VILLARDff64abe2012-02-02 16:20:01 +0100114 ret = of_parse_phandle_with_args(np, propname, "#gpio-cells",
Grant Likely15c9a0a2011-12-12 09:25:57 -0700115 cnt, NULL);
Anton Vorontsov74982092008-12-05 08:15:54 +0000116 /* A hole in the gpios = <> counts anyway. */
117 if (ret < 0 && ret != -EEXIST)
118 break;
119 } while (++cnt);
120
121 return cnt;
122}
Jean-Christophe PLAGNIOL-VILLARDff64abe2012-02-02 16:20:01 +0100123EXPORT_SYMBOL(of_gpio_named_count);
Anton Vorontsov74982092008-12-05 08:15:54 +0000124
125/**
Anton Vorontsovb908b532008-12-01 06:30:04 +0000126 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600127 * @gc: pointer to the gpio_chip structure
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000128 * @np: device node of the GPIO chip
129 * @gpio_spec: gpio specifier as found in the device tree
Anton Vorontsovb908b532008-12-01 06:30:04 +0000130 * @flags: a flags pointer to fill in
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000131 *
132 * This is simple translation function, suitable for the most 1:1 mapped
133 * gpio chips. This function performs only one sanity check: whether gpio
134 * is less than ngpios (that is specified in the gpio_chip).
135 */
Grant Likely15c9a0a2011-12-12 09:25:57 -0700136int of_gpio_simple_xlate(struct gpio_chip *gc,
137 const struct of_phandle_args *gpiospec, u32 *flags)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000138{
Anton Vorontsovb908b532008-12-01 06:30:04 +0000139 /*
140 * We're discouraging gpio_cells < 2, since that way you'll have to
141 * write your own xlate function (that will have to retrive the GPIO
142 * number and the flags from a single gpio cell -- this is possible,
143 * but not recommended).
144 */
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600145 if (gc->of_gpio_n_cells < 2) {
Anton Vorontsovb908b532008-12-01 06:30:04 +0000146 WARN_ON(1);
147 return -EINVAL;
148 }
149
Grant Likely15c9a0a2011-12-12 09:25:57 -0700150 if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells))
151 return -EINVAL;
152
Roland Stigge6270d832012-04-04 02:02:58 +0200153 if (gpiospec->args[0] >= gc->ngpio)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000154 return -EINVAL;
155
Anton Vorontsovb908b532008-12-01 06:30:04 +0000156 if (flags)
Grant Likely15c9a0a2011-12-12 09:25:57 -0700157 *flags = gpiospec->args[1];
Anton Vorontsovb908b532008-12-01 06:30:04 +0000158
Grant Likely15c9a0a2011-12-12 09:25:57 -0700159 return gpiospec->args[0];
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000160}
Jamie Iles3038bbd2011-07-28 16:25:41 +0100161EXPORT_SYMBOL(of_gpio_simple_xlate);
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000162
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000163/**
164 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
165 * @np: device node of the GPIO chip
166 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
167 *
168 * To use this function you should allocate and fill mm_gc with:
169 *
170 * 1) In the gpio_chip structure:
171 * - all the callbacks
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600172 * - of_gpio_n_cells
173 * - of_xlate callback (optional)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000174 *
175 * 3) In the of_mm_gpio_chip structure:
176 * - save_regs callback (optional)
177 *
178 * If succeeded, this function will map bank's memory and will
179 * do all necessary work for you. Then you'll able to use .regs
180 * to manage GPIOs from the callbacks.
181 */
182int of_mm_gpiochip_add(struct device_node *np,
183 struct of_mm_gpio_chip *mm_gc)
184{
185 int ret = -ENOMEM;
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600186 struct gpio_chip *gc = &mm_gc->gc;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000187
188 gc->label = kstrdup(np->full_name, GFP_KERNEL);
189 if (!gc->label)
190 goto err0;
191
192 mm_gc->regs = of_iomap(np, 0);
193 if (!mm_gc->regs)
194 goto err1;
195
Anton Vorontsov21451152008-04-30 00:05:24 +1000196 gc->base = -1;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000197
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000198 if (mm_gc->save_regs)
199 mm_gc->save_regs(mm_gc);
200
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600201 mm_gc->gc.of_node = np;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000202
203 ret = gpiochip_add(gc);
204 if (ret)
205 goto err2;
206
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000207 return 0;
208err2:
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000209 iounmap(mm_gc->regs);
210err1:
211 kfree(gc->label);
212err0:
213 pr_err("%s: GPIO chip registration failed with status %d\n",
214 np->full_name, ret);
215 return ret;
216}
217EXPORT_SYMBOL(of_mm_gpiochip_add);
Grant Likely594fa262010-06-08 07:48:16 -0600218
Anton Vorontsov391c9702010-06-08 07:48:17 -0600219void of_gpiochip_add(struct gpio_chip *chip)
220{
221 if ((!chip->of_node) && (chip->dev))
222 chip->of_node = chip->dev->of_node;
223
224 if (!chip->of_node)
225 return;
226
227 if (!chip->of_xlate) {
228 chip->of_gpio_n_cells = 2;
229 chip->of_xlate = of_gpio_simple_xlate;
230 }
231
232 of_node_get(chip->of_node);
233}
234
235void of_gpiochip_remove(struct gpio_chip *chip)
236{
237 if (chip->of_node)
238 of_node_put(chip->of_node);
239}