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863fbf49 AV |
1 | /* |
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> | |
18 | #include <linux/of_gpio.h> | |
19 | #include <asm/prom.h> | |
20 | ||
21 | /** | |
22 | * of_get_gpio - Get a GPIO number from the device tree to use with GPIO API | |
23 | * @np: device node to get GPIO from | |
24 | * @index: index of the GPIO | |
25 | * | |
26 | * Returns GPIO number to use with Linux generic GPIO API, or one of the errno | |
27 | * value on the error condition. | |
28 | */ | |
29 | int of_get_gpio(struct device_node *np, int index) | |
30 | { | |
31 | int ret = -EINVAL; | |
32 | struct device_node *gc; | |
33 | struct of_gpio_chip *of_gc = NULL; | |
34 | int size; | |
35 | const u32 *gpios; | |
36 | u32 nr_cells; | |
37 | int i; | |
38 | const void *gpio_spec; | |
39 | const u32 *gpio_cells; | |
40 | int gpio_index = 0; | |
41 | ||
42 | gpios = of_get_property(np, "gpios", &size); | |
43 | if (!gpios) { | |
44 | ret = -ENOENT; | |
45 | goto err0; | |
46 | } | |
47 | nr_cells = size / sizeof(u32); | |
48 | ||
49 | for (i = 0; i < nr_cells; gpio_index++) { | |
50 | const phandle *gpio_phandle; | |
51 | ||
52 | gpio_phandle = gpios + i; | |
53 | gpio_spec = gpio_phandle + 1; | |
54 | ||
55 | /* one cell hole in the gpios = <>; */ | |
56 | if (!*gpio_phandle) { | |
57 | if (gpio_index == index) | |
58 | return -ENOENT; | |
59 | i++; | |
60 | continue; | |
61 | } | |
62 | ||
63 | gc = of_find_node_by_phandle(*gpio_phandle); | |
64 | if (!gc) { | |
65 | pr_debug("%s: could not find phandle for gpios\n", | |
66 | np->full_name); | |
67 | goto err0; | |
68 | } | |
69 | ||
70 | of_gc = gc->data; | |
71 | if (!of_gc) { | |
72 | pr_debug("%s: gpio controller %s isn't registered\n", | |
73 | np->full_name, gc->full_name); | |
74 | goto err1; | |
75 | } | |
76 | ||
77 | gpio_cells = of_get_property(gc, "#gpio-cells", &size); | |
78 | if (!gpio_cells || size != sizeof(*gpio_cells) || | |
79 | *gpio_cells != of_gc->gpio_cells) { | |
80 | pr_debug("%s: wrong #gpio-cells for %s\n", | |
81 | np->full_name, gc->full_name); | |
82 | goto err1; | |
83 | } | |
84 | ||
85 | /* Next phandle is at phandle cells + #gpio-cells */ | |
86 | i += sizeof(*gpio_phandle) / sizeof(u32) + *gpio_cells; | |
87 | if (i >= nr_cells + 1) { | |
88 | pr_debug("%s: insufficient gpio-spec length\n", | |
89 | np->full_name); | |
90 | goto err1; | |
91 | } | |
92 | ||
93 | if (gpio_index == index) | |
94 | break; | |
95 | ||
96 | of_gc = NULL; | |
97 | of_node_put(gc); | |
98 | } | |
99 | ||
100 | if (!of_gc) { | |
101 | ret = -ENOENT; | |
102 | goto err0; | |
103 | } | |
104 | ||
105 | ret = of_gc->xlate(of_gc, np, gpio_spec); | |
106 | if (ret < 0) | |
107 | goto err1; | |
108 | ||
109 | ret += of_gc->gc.base; | |
110 | err1: | |
111 | of_node_put(gc); | |
112 | err0: | |
113 | pr_debug("%s exited with status %d\n", __func__, ret); | |
114 | return ret; | |
115 | } | |
116 | EXPORT_SYMBOL(of_get_gpio); | |
117 | ||
118 | /** | |
119 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number | |
120 | * @of_gc: pointer to the of_gpio_chip structure | |
121 | * @np: device node of the GPIO chip | |
122 | * @gpio_spec: gpio specifier as found in the device tree | |
123 | * | |
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 | */ | |
128 | int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np, | |
129 | const void *gpio_spec) | |
130 | { | |
131 | const u32 *gpio = gpio_spec; | |
132 | ||
133 | if (*gpio > of_gc->gc.ngpio) | |
134 | return -EINVAL; | |
135 | ||
136 | return *gpio; | |
137 | } | |
138 | EXPORT_SYMBOL(of_gpio_simple_xlate); | |
139 | ||
863fbf49 AV |
140 | /** |
141 | * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) | |
142 | * @np: device node of the GPIO chip | |
143 | * @mm_gc: pointer to the of_mm_gpio_chip allocated structure | |
144 | * | |
145 | * To use this function you should allocate and fill mm_gc with: | |
146 | * | |
147 | * 1) In the gpio_chip structure: | |
148 | * - all the callbacks | |
149 | * | |
150 | * 2) In the of_gpio_chip structure: | |
151 | * - gpio_cells | |
152 | * - xlate callback (optional) | |
153 | * | |
154 | * 3) In the of_mm_gpio_chip structure: | |
155 | * - save_regs callback (optional) | |
156 | * | |
157 | * If succeeded, this function will map bank's memory and will | |
158 | * do all necessary work for you. Then you'll able to use .regs | |
159 | * to manage GPIOs from the callbacks. | |
160 | */ | |
161 | int of_mm_gpiochip_add(struct device_node *np, | |
162 | struct of_mm_gpio_chip *mm_gc) | |
163 | { | |
164 | int ret = -ENOMEM; | |
165 | struct of_gpio_chip *of_gc = &mm_gc->of_gc; | |
166 | struct gpio_chip *gc = &of_gc->gc; | |
167 | ||
168 | gc->label = kstrdup(np->full_name, GFP_KERNEL); | |
169 | if (!gc->label) | |
170 | goto err0; | |
171 | ||
172 | mm_gc->regs = of_iomap(np, 0); | |
173 | if (!mm_gc->regs) | |
174 | goto err1; | |
175 | ||
21451155 | 176 | gc->base = -1; |
863fbf49 AV |
177 | |
178 | if (!of_gc->xlate) | |
179 | of_gc->xlate = of_gpio_simple_xlate; | |
180 | ||
181 | if (mm_gc->save_regs) | |
182 | mm_gc->save_regs(mm_gc); | |
183 | ||
184 | np->data = of_gc; | |
185 | ||
186 | ret = gpiochip_add(gc); | |
187 | if (ret) | |
188 | goto err2; | |
189 | ||
190 | /* We don't want to lose the node and its ->data */ | |
191 | of_node_get(np); | |
192 | ||
193 | pr_debug("%s: registered as generic GPIO chip, base is %d\n", | |
194 | np->full_name, gc->base); | |
195 | return 0; | |
196 | err2: | |
197 | np->data = NULL; | |
198 | iounmap(mm_gc->regs); | |
199 | err1: | |
200 | kfree(gc->label); | |
201 | err0: | |
202 | pr_err("%s: GPIO chip registration failed with status %d\n", | |
203 | np->full_name, ret); | |
204 | return ret; | |
205 | } | |
206 | EXPORT_SYMBOL(of_mm_gpiochip_add); |