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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> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
863fbf49 AV |
19 | #include <linux/of_gpio.h> |
20 | #include <asm/prom.h> | |
21 | ||
22 | /** | |
b908b53d | 23 | * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API |
863fbf49 AV |
24 | * @np: device node to get GPIO from |
25 | * @index: index of the GPIO | |
b908b53d | 26 | * @flags: a flags pointer to fill in |
863fbf49 AV |
27 | * |
28 | * Returns GPIO number to use with Linux generic GPIO API, or one of the errno | |
b908b53d AV |
29 | * value on the error condition. If @flags is not NULL the function also fills |
30 | * in flags for the GPIO. | |
863fbf49 | 31 | */ |
b908b53d AV |
32 | int of_get_gpio_flags(struct device_node *np, int index, |
33 | enum of_gpio_flags *flags) | |
863fbf49 | 34 | { |
64b60e09 | 35 | int ret; |
863fbf49 AV |
36 | struct device_node *gc; |
37 | struct of_gpio_chip *of_gc = NULL; | |
38 | int size; | |
863fbf49 | 39 | const void *gpio_spec; |
33714881 | 40 | const __be32 *gpio_cells; |
863fbf49 | 41 | |
64b60e09 AV |
42 | ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index, |
43 | &gc, &gpio_spec); | |
44 | if (ret) { | |
45 | pr_debug("%s: can't parse gpios property\n", __func__); | |
863fbf49 AV |
46 | goto err0; |
47 | } | |
863fbf49 | 48 | |
64b60e09 AV |
49 | of_gc = gc->data; |
50 | if (!of_gc) { | |
51 | pr_debug("%s: gpio controller %s isn't registered\n", | |
52 | np->full_name, gc->full_name); | |
53 | ret = -ENODEV; | |
54 | goto err1; | |
863fbf49 AV |
55 | } |
56 | ||
64b60e09 AV |
57 | gpio_cells = of_get_property(gc, "#gpio-cells", &size); |
58 | if (!gpio_cells || size != sizeof(*gpio_cells) || | |
33714881 | 59 | be32_to_cpup(gpio_cells) != of_gc->gpio_cells) { |
64b60e09 AV |
60 | pr_debug("%s: wrong #gpio-cells for %s\n", |
61 | np->full_name, gc->full_name); | |
62 | ret = -EINVAL; | |
63 | goto err1; | |
863fbf49 AV |
64 | } |
65 | ||
b908b53d AV |
66 | /* .xlate might decide to not fill in the flags, so clear it. */ |
67 | if (flags) | |
68 | *flags = 0; | |
69 | ||
70 | ret = of_gc->xlate(of_gc, np, gpio_spec, flags); | |
863fbf49 AV |
71 | if (ret < 0) |
72 | goto err1; | |
73 | ||
74 | ret += of_gc->gc.base; | |
75 | err1: | |
76 | of_node_put(gc); | |
77 | err0: | |
78 | pr_debug("%s exited with status %d\n", __func__, ret); | |
79 | return ret; | |
80 | } | |
b908b53d | 81 | EXPORT_SYMBOL(of_get_gpio_flags); |
863fbf49 | 82 | |
74982092 AV |
83 | /** |
84 | * 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 | */ | |
99 | unsigned 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 | } | |
115 | EXPORT_SYMBOL(of_gpio_count); | |
116 | ||
863fbf49 | 117 | /** |
b908b53d | 118 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags |
863fbf49 AV |
119 | * @of_gc: pointer to the of_gpio_chip structure |
120 | * @np: device node of the GPIO chip | |
121 | * @gpio_spec: gpio specifier as found in the device tree | |
b908b53d | 122 | * @flags: a flags pointer to fill in |
863fbf49 AV |
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, | |
b908b53d | 129 | const void *gpio_spec, enum of_gpio_flags *flags) |
863fbf49 | 130 | { |
33714881 JK |
131 | const __be32 *gpio = gpio_spec; |
132 | const u32 n = be32_to_cpup(gpio); | |
863fbf49 | 133 | |
b908b53d AV |
134 | /* |
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 | */ | |
140 | if (of_gc->gpio_cells < 2) { | |
141 | WARN_ON(1); | |
142 | return -EINVAL; | |
143 | } | |
144 | ||
33714881 | 145 | if (n > of_gc->gc.ngpio) |
863fbf49 AV |
146 | return -EINVAL; |
147 | ||
b908b53d | 148 | if (flags) |
33714881 | 149 | *flags = be32_to_cpu(gpio[1]); |
b908b53d | 150 | |
33714881 | 151 | return n; |
863fbf49 AV |
152 | } |
153 | EXPORT_SYMBOL(of_gpio_simple_xlate); | |
154 | ||
863fbf49 AV |
155 | /** |
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 | |
164 | * | |
165 | * 2) In the of_gpio_chip structure: | |
166 | * - gpio_cells | |
167 | * - xlate callback (optional) | |
168 | * | |
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 | */ | |
176 | int of_mm_gpiochip_add(struct device_node *np, | |
177 | struct of_mm_gpio_chip *mm_gc) | |
178 | { | |
179 | int ret = -ENOMEM; | |
180 | struct of_gpio_chip *of_gc = &mm_gc->of_gc; | |
181 | struct gpio_chip *gc = &of_gc->gc; | |
182 | ||
183 | gc->label = kstrdup(np->full_name, GFP_KERNEL); | |
184 | if (!gc->label) | |
185 | goto err0; | |
186 | ||
187 | mm_gc->regs = of_iomap(np, 0); | |
188 | if (!mm_gc->regs) | |
189 | goto err1; | |
190 | ||
21451155 | 191 | gc->base = -1; |
863fbf49 AV |
192 | |
193 | if (!of_gc->xlate) | |
194 | of_gc->xlate = of_gpio_simple_xlate; | |
195 | ||
196 | if (mm_gc->save_regs) | |
197 | mm_gc->save_regs(mm_gc); | |
198 | ||
199 | np->data = of_gc; | |
200 | ||
201 | ret = gpiochip_add(gc); | |
202 | if (ret) | |
203 | goto err2; | |
204 | ||
205 | /* We don't want to lose the node and its ->data */ | |
206 | of_node_get(np); | |
207 | ||
208 | pr_debug("%s: registered as generic GPIO chip, base is %d\n", | |
209 | np->full_name, gc->base); | |
210 | return 0; | |
211 | err2: | |
212 | np->data = NULL; | |
213 | iounmap(mm_gc->regs); | |
214 | err1: | |
215 | kfree(gc->label); | |
216 | err0: | |
217 | pr_err("%s: GPIO chip registration failed with status %d\n", | |
218 | np->full_name, ret); | |
219 | return ret; | |
220 | } | |
221 | EXPORT_SYMBOL(of_mm_gpiochip_add); |