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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 | { | |
64b60e09 | 31 | int ret; |
863fbf49 AV |
32 | struct device_node *gc; |
33 | struct of_gpio_chip *of_gc = NULL; | |
34 | int size; | |
863fbf49 AV |
35 | const void *gpio_spec; |
36 | const u32 *gpio_cells; | |
863fbf49 | 37 | |
64b60e09 AV |
38 | ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index, |
39 | &gc, &gpio_spec); | |
40 | if (ret) { | |
41 | pr_debug("%s: can't parse gpios property\n", __func__); | |
863fbf49 AV |
42 | goto err0; |
43 | } | |
863fbf49 | 44 | |
64b60e09 AV |
45 | of_gc = gc->data; |
46 | if (!of_gc) { | |
47 | pr_debug("%s: gpio controller %s isn't registered\n", | |
48 | np->full_name, gc->full_name); | |
49 | ret = -ENODEV; | |
50 | goto err1; | |
863fbf49 AV |
51 | } |
52 | ||
64b60e09 AV |
53 | gpio_cells = of_get_property(gc, "#gpio-cells", &size); |
54 | if (!gpio_cells || size != sizeof(*gpio_cells) || | |
55 | *gpio_cells != of_gc->gpio_cells) { | |
56 | pr_debug("%s: wrong #gpio-cells for %s\n", | |
57 | np->full_name, gc->full_name); | |
58 | ret = -EINVAL; | |
59 | goto err1; | |
863fbf49 AV |
60 | } |
61 | ||
62 | ret = of_gc->xlate(of_gc, np, gpio_spec); | |
63 | if (ret < 0) | |
64 | goto err1; | |
65 | ||
66 | ret += of_gc->gc.base; | |
67 | err1: | |
68 | of_node_put(gc); | |
69 | err0: | |
70 | pr_debug("%s exited with status %d\n", __func__, ret); | |
71 | return ret; | |
72 | } | |
73 | EXPORT_SYMBOL(of_get_gpio); | |
74 | ||
75 | /** | |
76 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number | |
77 | * @of_gc: pointer to the of_gpio_chip structure | |
78 | * @np: device node of the GPIO chip | |
79 | * @gpio_spec: gpio specifier as found in the device tree | |
80 | * | |
81 | * This is simple translation function, suitable for the most 1:1 mapped | |
82 | * gpio chips. This function performs only one sanity check: whether gpio | |
83 | * is less than ngpios (that is specified in the gpio_chip). | |
84 | */ | |
85 | int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np, | |
86 | const void *gpio_spec) | |
87 | { | |
88 | const u32 *gpio = gpio_spec; | |
89 | ||
90 | if (*gpio > of_gc->gc.ngpio) | |
91 | return -EINVAL; | |
92 | ||
93 | return *gpio; | |
94 | } | |
95 | EXPORT_SYMBOL(of_gpio_simple_xlate); | |
96 | ||
863fbf49 AV |
97 | /** |
98 | * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) | |
99 | * @np: device node of the GPIO chip | |
100 | * @mm_gc: pointer to the of_mm_gpio_chip allocated structure | |
101 | * | |
102 | * To use this function you should allocate and fill mm_gc with: | |
103 | * | |
104 | * 1) In the gpio_chip structure: | |
105 | * - all the callbacks | |
106 | * | |
107 | * 2) In the of_gpio_chip structure: | |
108 | * - gpio_cells | |
109 | * - xlate callback (optional) | |
110 | * | |
111 | * 3) In the of_mm_gpio_chip structure: | |
112 | * - save_regs callback (optional) | |
113 | * | |
114 | * If succeeded, this function will map bank's memory and will | |
115 | * do all necessary work for you. Then you'll able to use .regs | |
116 | * to manage GPIOs from the callbacks. | |
117 | */ | |
118 | int of_mm_gpiochip_add(struct device_node *np, | |
119 | struct of_mm_gpio_chip *mm_gc) | |
120 | { | |
121 | int ret = -ENOMEM; | |
122 | struct of_gpio_chip *of_gc = &mm_gc->of_gc; | |
123 | struct gpio_chip *gc = &of_gc->gc; | |
124 | ||
125 | gc->label = kstrdup(np->full_name, GFP_KERNEL); | |
126 | if (!gc->label) | |
127 | goto err0; | |
128 | ||
129 | mm_gc->regs = of_iomap(np, 0); | |
130 | if (!mm_gc->regs) | |
131 | goto err1; | |
132 | ||
21451155 | 133 | gc->base = -1; |
863fbf49 AV |
134 | |
135 | if (!of_gc->xlate) | |
136 | of_gc->xlate = of_gpio_simple_xlate; | |
137 | ||
138 | if (mm_gc->save_regs) | |
139 | mm_gc->save_regs(mm_gc); | |
140 | ||
141 | np->data = of_gc; | |
142 | ||
143 | ret = gpiochip_add(gc); | |
144 | if (ret) | |
145 | goto err2; | |
146 | ||
147 | /* We don't want to lose the node and its ->data */ | |
148 | of_node_get(np); | |
149 | ||
150 | pr_debug("%s: registered as generic GPIO chip, base is %d\n", | |
151 | np->full_name, gc->base); | |
152 | return 0; | |
153 | err2: | |
154 | np->data = NULL; | |
155 | iounmap(mm_gc->regs); | |
156 | err1: | |
157 | kfree(gc->label); | |
158 | err0: | |
159 | pr_err("%s: GPIO chip registration failed with status %d\n", | |
160 | np->full_name, ret); | |
161 | return ret; | |
162 | } | |
163 | EXPORT_SYMBOL(of_mm_gpiochip_add); |