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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
14#include <linux/kernel.h>
15#include <linux/errno.h>
16#include <linux/io.h>
17#include <linux/of.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090018#include <linux/slab.h>
Anton Vorontsov863fbf42008-04-11 23:06:45 +100019#include <linux/of_gpio.h>
20#include <asm/prom.h>
21
22/**
Anton Vorontsovb908b532008-12-01 06:30:04 +000023 * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API
Anton Vorontsov863fbf42008-04-11 23:06:45 +100024 * @np: device node to get GPIO from
25 * @index: index of the GPIO
Anton Vorontsovb908b532008-12-01 06:30:04 +000026 * @flags: a flags pointer to fill in
Anton Vorontsov863fbf42008-04-11 23:06:45 +100027 *
28 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
Anton Vorontsovb908b532008-12-01 06:30:04 +000029 * value on the error condition. If @flags is not NULL the function also fills
30 * in flags for the GPIO.
Anton Vorontsov863fbf42008-04-11 23:06:45 +100031 */
Anton Vorontsovb908b532008-12-01 06:30:04 +000032int of_get_gpio_flags(struct device_node *np, int index,
33 enum of_gpio_flags *flags)
Anton Vorontsov863fbf42008-04-11 23:06:45 +100034{
Anton Vorontsov64b60e02008-10-10 04:43:17 +000035 int ret;
Anton Vorontsova19e3da2010-06-08 07:48:16 -060036 struct device_node *gpio_np;
37 struct gpio_chip *gc;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100038 int size;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100039 const void *gpio_spec;
Jeremy Kerr33714882010-01-30 01:45:26 -070040 const __be32 *gpio_cells;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100041
Anton Vorontsov64b60e02008-10-10 04:43:17 +000042 ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index,
Anton Vorontsova19e3da2010-06-08 07:48:16 -060043 &gpio_np, &gpio_spec);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000044 if (ret) {
45 pr_debug("%s: can't parse gpios property\n", __func__);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100046 goto err0;
47 }
Anton Vorontsov863fbf42008-04-11 23:06:45 +100048
Anton Vorontsova19e3da2010-06-08 07:48:16 -060049 gc = gpio_np->data;
50 if (!gc) {
Anton Vorontsov64b60e02008-10-10 04:43:17 +000051 pr_debug("%s: gpio controller %s isn't registered\n",
Anton Vorontsova19e3da2010-06-08 07:48:16 -060052 np->full_name, gpio_np->full_name);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000053 ret = -ENODEV;
54 goto err1;
55 }
56
Anton Vorontsova19e3da2010-06-08 07:48:16 -060057 gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000058 if (!gpio_cells || size != sizeof(*gpio_cells) ||
Anton Vorontsova19e3da2010-06-08 07:48:16 -060059 be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) {
Anton Vorontsov64b60e02008-10-10 04:43:17 +000060 pr_debug("%s: wrong #gpio-cells for %s\n",
Anton Vorontsova19e3da2010-06-08 07:48:16 -060061 np->full_name, gpio_np->full_name);
Anton Vorontsov64b60e02008-10-10 04:43:17 +000062 ret = -EINVAL;
63 goto err1;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100064 }
65
Anton Vorontsovb908b532008-12-01 06:30:04 +000066 /* .xlate might decide to not fill in the flags, so clear it. */
67 if (flags)
68 *flags = 0;
69
Anton Vorontsova19e3da2010-06-08 07:48:16 -060070 ret = gc->of_xlate(gc, np, gpio_spec, flags);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100071 if (ret < 0)
72 goto err1;
73
Anton Vorontsova19e3da2010-06-08 07:48:16 -060074 ret += gc->base;
Anton Vorontsov863fbf42008-04-11 23:06:45 +100075err1:
Anton Vorontsova19e3da2010-06-08 07:48:16 -060076 of_node_put(gpio_np);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100077err0:
78 pr_debug("%s exited with status %d\n", __func__, ret);
79 return ret;
80}
Anton Vorontsovb908b532008-12-01 06:30:04 +000081EXPORT_SYMBOL(of_get_gpio_flags);
Anton Vorontsov863fbf42008-04-11 23:06:45 +100082
83/**
Anton Vorontsov74982092008-12-05 08:15:54 +000084 * of_gpio_count - Count GPIOs for a device
85 * @np: device node to count GPIOs for
86 *
87 * The function returns the count of GPIOs specified for a node.
88 *
89 * Note that the empty GPIO specifiers counts too. For example,
90 *
91 * gpios = <0
92 * &pio1 1 2
93 * 0
94 * &pio2 3 4>;
95 *
96 * defines four GPIOs (so this function will return 4), two of which
97 * are not specified.
98 */
99unsigned int of_gpio_count(struct device_node *np)
100{
101 unsigned int cnt = 0;
102
103 do {
104 int ret;
105
106 ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells",
107 cnt, NULL, NULL);
108 /* A hole in the gpios = <> counts anyway. */
109 if (ret < 0 && ret != -EEXIST)
110 break;
111 } while (++cnt);
112
113 return cnt;
114}
115EXPORT_SYMBOL(of_gpio_count);
116
117/**
Anton Vorontsovb908b532008-12-01 06:30:04 +0000118 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600119 * @gc: pointer to the gpio_chip structure
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000120 * @np: device node of the GPIO chip
121 * @gpio_spec: gpio specifier as found in the device tree
Anton Vorontsovb908b532008-12-01 06:30:04 +0000122 * @flags: a flags pointer to fill in
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000123 *
124 * This is simple translation function, suitable for the most 1:1 mapped
125 * gpio chips. This function performs only one sanity check: whether gpio
126 * is less than ngpios (that is specified in the gpio_chip).
127 */
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600128int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
129 const void *gpio_spec, u32 *flags)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000130{
Jeremy Kerr33714882010-01-30 01:45:26 -0700131 const __be32 *gpio = gpio_spec;
132 const u32 n = be32_to_cpup(gpio);
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000133
Anton Vorontsovb908b532008-12-01 06:30:04 +0000134 /*
135 * We're discouraging gpio_cells < 2, since that way you'll have to
136 * write your own xlate function (that will have to retrive the GPIO
137 * number and the flags from a single gpio cell -- this is possible,
138 * but not recommended).
139 */
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600140 if (gc->of_gpio_n_cells < 2) {
Anton Vorontsovb908b532008-12-01 06:30:04 +0000141 WARN_ON(1);
142 return -EINVAL;
143 }
144
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600145 if (n > gc->ngpio)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000146 return -EINVAL;
147
Anton Vorontsovb908b532008-12-01 06:30:04 +0000148 if (flags)
Jeremy Kerr33714882010-01-30 01:45:26 -0700149 *flags = be32_to_cpu(gpio[1]);
Anton Vorontsovb908b532008-12-01 06:30:04 +0000150
Jeremy Kerr33714882010-01-30 01:45:26 -0700151 return n;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000152}
153EXPORT_SYMBOL(of_gpio_simple_xlate);
154
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000155/**
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
159 *
160 * To use this function you should allocate and fill mm_gc with:
161 *
162 * 1) In the gpio_chip structure:
163 * - all the callbacks
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600164 * - of_gpio_n_cells
165 * - of_xlate callback (optional)
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000166 *
167 * 3) In the of_mm_gpio_chip structure:
168 * - save_regs callback (optional)
169 *
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.
173 */
174int of_mm_gpiochip_add(struct device_node *np,
175 struct of_mm_gpio_chip *mm_gc)
176{
177 int ret = -ENOMEM;
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600178 struct gpio_chip *gc = &mm_gc->gc;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000179
180 gc->label = kstrdup(np->full_name, GFP_KERNEL);
181 if (!gc->label)
182 goto err0;
183
184 mm_gc->regs = of_iomap(np, 0);
185 if (!mm_gc->regs)
186 goto err1;
187
Anton Vorontsov21451152008-04-30 00:05:24 +1000188 gc->base = -1;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000189
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600190 if (!gc->of_xlate)
191 gc->of_xlate = of_gpio_simple_xlate;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000192
193 if (mm_gc->save_regs)
194 mm_gc->save_regs(mm_gc);
195
Anton Vorontsova19e3da2010-06-08 07:48:16 -0600196 np->data = &mm_gc->gc;
197 mm_gc->gc.of_node = np;
Anton Vorontsov863fbf42008-04-11 23:06:45 +1000198
199 ret = gpiochip_add(gc);
200 if (ret)
201 goto err2;
202
203 /* We don't want to lose the node and its ->data */
204 of_node_get(np);
205
206 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
207 np->full_name, gc->base);
208 return 0;
209err2:
210 np->data = NULL;
211 iounmap(mm_gc->regs);
212err1:
213 kfree(gc->label);
214err0:
215 pr_err("%s: GPIO chip registration failed with status %d\n",
216 np->full_name, ret);
217 return ret;
218}
219EXPORT_SYMBOL(of_mm_gpiochip_add);