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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>
18#include <linux/of.h>
Grant Likely2e13cba2010-07-05 16:11:55 -060019#include <linux/of_address.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100020#include <linux/of_gpio.h>
Grant Likely2e13cba2010-07-05 16:11:55 -060021#include <linux/slab.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100022
23/**
John Bonesioa6b09192011-06-27 16:49:57 -070024 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
Anton Vorontsov863fbf42008-04-11 23:06:45 +100025 * @np: device node to get GPIO from
John Bonesioa6b09192011-06-27 16:49:57 -070026 * @propname: property name containing gpio specifier(s)
Anton Vorontsov863fbf42008-04-11 23:06:45 +100027 * @index: index of the GPIO
Anton Vorontsovb908b532008-12-01 06:30:04 +000028 * @flags: a flags pointer to fill in
Anton Vorontsov863fbf42008-04-11 23:06:45 +100029 *
30 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
Anton Vorontsovb908b532008-12-01 06:30:04 +000031 * value on the error condition. If @flags is not NULL the function also fills
32 * in flags for the GPIO.
Anton Vorontsov863fbf42008-04-11 23:06:45 +100033 */
John Bonesioa6b09192011-06-27 16:49:57 -070034int of_get_named_gpio_flags(struct device_node *np, const char *propname,
35 int index, enum of_gpio_flags *flags)
Anton Vorontsov863fbf42008-04-11 23:06:45 +100036{
Anton Vorontsov64b60e02008-10-10 04:43:17 +000037 int ret;
Anton Vorontsova19e3da2010-06-08 07:48:16 -060038 struct device_node *gpio_np;
39 struct gpio_chip *gc;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100040 int size;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100041 const void *gpio_spec;
Jeremy Kerr33714882010-01-30 01:45:26 -070042 const __be32 *gpio_cells;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100043
John Bonesioa6b09192011-06-27 16:49:57 -070044 ret = of_parse_phandles_with_args(np, propname, "#gpio-cells", index,
Anton Vorontsova19e3da2010-06-08 07:48:16 -060045 &gpio_np, &gpio_spec);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000046 if (ret) {
47 pr_debug("%s: can't parse gpios property\n", __func__);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100048 goto err0;
49 }
Anton Vorontsov863fbf42008-04-11 23:06:45 +100050
Grant Likely594fa262010-06-08 07:48:16 -060051 gc = of_node_to_gpiochip(gpio_np);
Anton Vorontsova19e3da2010-06-08 07:48:16 -060052 if (!gc) {
Anton Vorontsov64b60e02008-10-10 04:43:17 +000053 pr_debug("%s: gpio controller %s isn't registered\n",
Anton Vorontsova19e3da2010-06-08 07:48:16 -060054 np->full_name, gpio_np->full_name);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000055 ret = -ENODEV;
56 goto err1;
57 }
58
Anton Vorontsova19e3da2010-06-08 07:48:16 -060059 gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000060 if (!gpio_cells || size != sizeof(*gpio_cells) ||
Anton Vorontsova19e3da2010-06-08 07:48:16 -060061 be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) {
Anton Vorontsov64b60e02008-10-10 04:43:17 +000062 pr_debug("%s: wrong #gpio-cells for %s\n",
Anton Vorontsova19e3da2010-06-08 07:48:16 -060063 np->full_name, gpio_np->full_name);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000064 ret = -EINVAL;
65 goto err1;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100066 }
67
Anton Vorontsovb908b532008-12-01 06:30:04 +000068 /* .xlate might decide to not fill in the flags, so clear it. */
69 if (flags)
70 *flags = 0;
71
Anton Vorontsova19e3da2010-06-08 07:48:16 -060072 ret = gc->of_xlate(gc, np, gpio_spec, flags);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100073 if (ret < 0)
74 goto err1;
75
Anton Vorontsova19e3da2010-06-08 07:48:16 -060076 ret += gc->base;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100077err1:
Anton Vorontsova19e3da2010-06-08 07:48:16 -060078 of_node_put(gpio_np);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100079err0:
80 pr_debug("%s exited with status %d\n", __func__, ret);
81 return ret;
82}
John Bonesioa6b09192011-06-27 16:49:57 -070083EXPORT_SYMBOL(of_get_named_gpio_flags);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100084
85/**
Anton Vorontsov74982092008-12-05 08:15:54 +000086 * of_gpio_count - Count GPIOs for a device
87 * @np: device node to count GPIOs for
88 *
89 * The function returns the count of GPIOs specified for a node.
90 *
91 * Note that the empty GPIO specifiers counts too. For example,
92 *
93 * gpios = <0
94 * &pio1 1 2
95 * 0
96 * &pio2 3 4>;
97 *
98 * defines four GPIOs (so this function will return 4), two of which
99 * are not specified.
100 */
101unsigned int of_gpio_count(struct device_node *np)
102{
103 unsigned int cnt = 0;
104
105 do {
106 int ret;
107
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);
114
115 return cnt;
116}
117EXPORT_SYMBOL(of_gpio_count);
118
119/**
Anton Vorontsovb908b532008-12-01 06:30:04 +0000120 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600121 * @gc: pointer to the gpio_chip structure
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000122 * @np: device node of the GPIO chip
123 * @gpio_spec: gpio specifier as found in the device tree
Anton Vorontsovb908b532008-12-01 06:30:04 +0000124 * @flags: a flags pointer to fill in
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000125 *
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).
129 */
Jamie Iles3038bbdf2011-07-28 16:25:41 +0100130int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
131 const void *gpio_spec, u32 *flags)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000132{
Jeremy Kerr33714882010-01-30 01:45:26 -0700133 const __be32 *gpio = gpio_spec;
134 const u32 n = be32_to_cpup(gpio);
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000135
Anton Vorontsovb908b532008-12-01 06:30:04 +0000136 /*
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).
141 */
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600142 if (gc->of_gpio_n_cells < 2) {
Anton Vorontsovb908b532008-12-01 06:30:04 +0000143 WARN_ON(1);
144 return -EINVAL;
145 }
146
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600147 if (n > gc->ngpio)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000148 return -EINVAL;
149
Anton Vorontsovb908b532008-12-01 06:30:04 +0000150 if (flags)
Jeremy Kerr33714882010-01-30 01:45:26 -0700151 *flags = be32_to_cpu(gpio[1]);
Anton Vorontsovb908b532008-12-01 06:30:04 +0000152
Jeremy Kerr33714882010-01-30 01:45:26 -0700153 return n;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000154}
Jamie Iles3038bbdf2011-07-28 16:25:41 +0100155EXPORT_SYMBOL(of_gpio_simple_xlate);
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000156
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000157/**
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
161 *
162 * To use this function you should allocate and fill mm_gc with:
163 *
164 * 1) In the gpio_chip structure:
165 * - all the callbacks
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600166 * - of_gpio_n_cells
167 * - of_xlate callback (optional)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000168 *
169 * 3) In the of_mm_gpio_chip structure:
170 * - save_regs callback (optional)
171 *
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.
175 */
176int of_mm_gpiochip_add(struct device_node *np,
177 struct of_mm_gpio_chip *mm_gc)
178{
179 int ret = -ENOMEM;
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600180 struct gpio_chip *gc = &mm_gc->gc;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000181
182 gc->label = kstrdup(np->full_name, GFP_KERNEL);
183 if (!gc->label)
184 goto err0;
185
186 mm_gc->regs = of_iomap(np, 0);
187 if (!mm_gc->regs)
188 goto err1;
189
Anton Vorontsov21451152008-04-30 00:05:24 +1000190 gc->base = -1;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000191
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000192 if (mm_gc->save_regs)
193 mm_gc->save_regs(mm_gc);
194
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600195 mm_gc->gc.of_node = np;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000196
197 ret = gpiochip_add(gc);
198 if (ret)
199 goto err2;
200
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000201 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
202 np->full_name, gc->base);
203 return 0;
204err2:
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000205 iounmap(mm_gc->regs);
206err1:
207 kfree(gc->label);
208err0:
209 pr_err("%s: GPIO chip registration failed with status %d\n",
210 np->full_name, ret);
211 return ret;
212}
213EXPORT_SYMBOL(of_mm_gpiochip_add);
Grant Likely594fa262010-06-08 07:48:16 -0600214
Anton Vorontsov391c9702010-06-08 07:48:17 -0600215void of_gpiochip_add(struct gpio_chip *chip)
216{
217 if ((!chip->of_node) && (chip->dev))
218 chip->of_node = chip->dev->of_node;
219
220 if (!chip->of_node)
221 return;
222
223 if (!chip->of_xlate) {
224 chip->of_gpio_n_cells = 2;
225 chip->of_xlate = of_gpio_simple_xlate;
226 }
227
228 of_node_get(chip->of_node);
229}
230
231void of_gpiochip_remove(struct gpio_chip *chip)
232{
233 if (chip->of_node)
234 of_node_put(chip->of_node);
235}
236
Grant Likely594fa262010-06-08 07:48:16 -0600237/* Private function for resolving node pointer to gpio_chip */
238static int of_gpiochip_is_match(struct gpio_chip *chip, void *data)
239{
240 return chip->of_node == data;
241}
242
243struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
244{
245 return gpiochip_find(np, of_gpiochip_is_match);
246}