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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 | /** | |
b908b53d | 22 | * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API |
863fbf49 AV |
23 | * @np: device node to get GPIO from |
24 | * @index: index of the GPIO | |
b908b53d | 25 | * @flags: a flags pointer to fill in |
863fbf49 AV |
26 | * |
27 | * Returns GPIO number to use with Linux generic GPIO API, or one of the errno | |
b908b53d AV |
28 | * value on the error condition. If @flags is not NULL the function also fills |
29 | * in flags for the GPIO. | |
863fbf49 | 30 | */ |
b908b53d AV |
31 | int of_get_gpio_flags(struct device_node *np, int index, |
32 | enum of_gpio_flags *flags) | |
863fbf49 | 33 | { |
64b60e09 | 34 | int ret; |
863fbf49 AV |
35 | struct device_node *gc; |
36 | struct of_gpio_chip *of_gc = NULL; | |
37 | int size; | |
863fbf49 AV |
38 | const void *gpio_spec; |
39 | const u32 *gpio_cells; | |
863fbf49 | 40 | |
64b60e09 AV |
41 | ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index, |
42 | &gc, &gpio_spec); | |
43 | if (ret) { | |
44 | pr_debug("%s: can't parse gpios property\n", __func__); | |
863fbf49 AV |
45 | goto err0; |
46 | } | |
863fbf49 | 47 | |
64b60e09 AV |
48 | of_gc = gc->data; |
49 | if (!of_gc) { | |
50 | pr_debug("%s: gpio controller %s isn't registered\n", | |
51 | np->full_name, gc->full_name); | |
52 | ret = -ENODEV; | |
53 | goto err1; | |
863fbf49 AV |
54 | } |
55 | ||
64b60e09 AV |
56 | gpio_cells = of_get_property(gc, "#gpio-cells", &size); |
57 | if (!gpio_cells || size != sizeof(*gpio_cells) || | |
58 | *gpio_cells != of_gc->gpio_cells) { | |
59 | pr_debug("%s: wrong #gpio-cells for %s\n", | |
60 | np->full_name, gc->full_name); | |
61 | ret = -EINVAL; | |
62 | goto err1; | |
863fbf49 AV |
63 | } |
64 | ||
b908b53d AV |
65 | /* .xlate might decide to not fill in the flags, so clear it. */ |
66 | if (flags) | |
67 | *flags = 0; | |
68 | ||
69 | ret = of_gc->xlate(of_gc, np, gpio_spec, flags); | |
863fbf49 AV |
70 | if (ret < 0) |
71 | goto err1; | |
72 | ||
73 | ret += of_gc->gc.base; | |
74 | err1: | |
75 | of_node_put(gc); | |
76 | err0: | |
77 | pr_debug("%s exited with status %d\n", __func__, ret); | |
78 | return ret; | |
79 | } | |
b908b53d | 80 | EXPORT_SYMBOL(of_get_gpio_flags); |
863fbf49 AV |
81 | |
82 | /** | |
b908b53d | 83 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags |
863fbf49 AV |
84 | * @of_gc: pointer to the of_gpio_chip structure |
85 | * @np: device node of the GPIO chip | |
86 | * @gpio_spec: gpio specifier as found in the device tree | |
b908b53d | 87 | * @flags: a flags pointer to fill in |
863fbf49 AV |
88 | * |
89 | * This is simple translation function, suitable for the most 1:1 mapped | |
90 | * gpio chips. This function performs only one sanity check: whether gpio | |
91 | * is less than ngpios (that is specified in the gpio_chip). | |
92 | */ | |
93 | int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np, | |
b908b53d | 94 | const void *gpio_spec, enum of_gpio_flags *flags) |
863fbf49 AV |
95 | { |
96 | const u32 *gpio = gpio_spec; | |
97 | ||
b908b53d AV |
98 | /* |
99 | * We're discouraging gpio_cells < 2, since that way you'll have to | |
100 | * write your own xlate function (that will have to retrive the GPIO | |
101 | * number and the flags from a single gpio cell -- this is possible, | |
102 | * but not recommended). | |
103 | */ | |
104 | if (of_gc->gpio_cells < 2) { | |
105 | WARN_ON(1); | |
106 | return -EINVAL; | |
107 | } | |
108 | ||
863fbf49 AV |
109 | if (*gpio > of_gc->gc.ngpio) |
110 | return -EINVAL; | |
111 | ||
b908b53d AV |
112 | if (flags) |
113 | *flags = gpio[1]; | |
114 | ||
863fbf49 AV |
115 | return *gpio; |
116 | } | |
117 | EXPORT_SYMBOL(of_gpio_simple_xlate); | |
118 | ||
863fbf49 AV |
119 | /** |
120 | * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) | |
121 | * @np: device node of the GPIO chip | |
122 | * @mm_gc: pointer to the of_mm_gpio_chip allocated structure | |
123 | * | |
124 | * To use this function you should allocate and fill mm_gc with: | |
125 | * | |
126 | * 1) In the gpio_chip structure: | |
127 | * - all the callbacks | |
128 | * | |
129 | * 2) In the of_gpio_chip structure: | |
130 | * - gpio_cells | |
131 | * - xlate callback (optional) | |
132 | * | |
133 | * 3) In the of_mm_gpio_chip structure: | |
134 | * - save_regs callback (optional) | |
135 | * | |
136 | * If succeeded, this function will map bank's memory and will | |
137 | * do all necessary work for you. Then you'll able to use .regs | |
138 | * to manage GPIOs from the callbacks. | |
139 | */ | |
140 | int of_mm_gpiochip_add(struct device_node *np, | |
141 | struct of_mm_gpio_chip *mm_gc) | |
142 | { | |
143 | int ret = -ENOMEM; | |
144 | struct of_gpio_chip *of_gc = &mm_gc->of_gc; | |
145 | struct gpio_chip *gc = &of_gc->gc; | |
146 | ||
147 | gc->label = kstrdup(np->full_name, GFP_KERNEL); | |
148 | if (!gc->label) | |
149 | goto err0; | |
150 | ||
151 | mm_gc->regs = of_iomap(np, 0); | |
152 | if (!mm_gc->regs) | |
153 | goto err1; | |
154 | ||
21451155 | 155 | gc->base = -1; |
863fbf49 AV |
156 | |
157 | if (!of_gc->xlate) | |
158 | of_gc->xlate = of_gpio_simple_xlate; | |
159 | ||
160 | if (mm_gc->save_regs) | |
161 | mm_gc->save_regs(mm_gc); | |
162 | ||
163 | np->data = of_gc; | |
164 | ||
165 | ret = gpiochip_add(gc); | |
166 | if (ret) | |
167 | goto err2; | |
168 | ||
169 | /* We don't want to lose the node and its ->data */ | |
170 | of_node_get(np); | |
171 | ||
172 | pr_debug("%s: registered as generic GPIO chip, base is %d\n", | |
173 | np->full_name, gc->base); | |
174 | return 0; | |
175 | err2: | |
176 | np->data = NULL; | |
177 | iounmap(mm_gc->regs); | |
178 | err1: | |
179 | kfree(gc->label); | |
180 | err0: | |
181 | pr_err("%s: GPIO chip registration failed with status %d\n", | |
182 | np->full_name, ret); | |
183 | return ret; | |
184 | } | |
185 | EXPORT_SYMBOL(of_mm_gpiochip_add); |