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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 | ||
2e13cba8 | 14 | #include <linux/device.h> |
863fbf49 | 15 | #include <linux/errno.h> |
2e13cba8 | 16 | #include <linux/module.h> |
863fbf49 AV |
17 | #include <linux/io.h> |
18 | #include <linux/of.h> | |
2e13cba8 | 19 | #include <linux/of_address.h> |
863fbf49 | 20 | #include <linux/of_gpio.h> |
2e13cba8 | 21 | #include <linux/slab.h> |
863fbf49 AV |
22 | |
23 | /** | |
b908b53d | 24 | * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API |
863fbf49 AV |
25 | * @np: device node to get GPIO from |
26 | * @index: index of the GPIO | |
b908b53d | 27 | * @flags: a flags pointer to fill in |
863fbf49 AV |
28 | * |
29 | * Returns GPIO number to use with Linux generic GPIO API, or one of the errno | |
b908b53d AV |
30 | * value on the error condition. If @flags is not NULL the function also fills |
31 | * in flags for the GPIO. | |
863fbf49 | 32 | */ |
b908b53d AV |
33 | int of_get_gpio_flags(struct device_node *np, int index, |
34 | enum of_gpio_flags *flags) | |
863fbf49 | 35 | { |
64b60e09 | 36 | int ret; |
a19e3da5 AV |
37 | struct device_node *gpio_np; |
38 | struct gpio_chip *gc; | |
863fbf49 | 39 | int size; |
863fbf49 | 40 | const void *gpio_spec; |
33714881 | 41 | const __be32 *gpio_cells; |
863fbf49 | 42 | |
64b60e09 | 43 | ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index, |
a19e3da5 | 44 | &gpio_np, &gpio_spec); |
64b60e09 AV |
45 | if (ret) { |
46 | pr_debug("%s: can't parse gpios property\n", __func__); | |
863fbf49 AV |
47 | goto err0; |
48 | } | |
863fbf49 | 49 | |
594fa265 | 50 | gc = of_node_to_gpiochip(gpio_np); |
a19e3da5 | 51 | if (!gc) { |
64b60e09 | 52 | pr_debug("%s: gpio controller %s isn't registered\n", |
a19e3da5 | 53 | np->full_name, gpio_np->full_name); |
64b60e09 AV |
54 | ret = -ENODEV; |
55 | goto err1; | |
863fbf49 AV |
56 | } |
57 | ||
a19e3da5 | 58 | gpio_cells = of_get_property(gpio_np, "#gpio-cells", &size); |
64b60e09 | 59 | if (!gpio_cells || size != sizeof(*gpio_cells) || |
a19e3da5 | 60 | be32_to_cpup(gpio_cells) != gc->of_gpio_n_cells) { |
64b60e09 | 61 | pr_debug("%s: wrong #gpio-cells for %s\n", |
a19e3da5 | 62 | np->full_name, gpio_np->full_name); |
64b60e09 AV |
63 | ret = -EINVAL; |
64 | goto err1; | |
863fbf49 AV |
65 | } |
66 | ||
b908b53d AV |
67 | /* .xlate might decide to not fill in the flags, so clear it. */ |
68 | if (flags) | |
69 | *flags = 0; | |
70 | ||
a19e3da5 | 71 | ret = gc->of_xlate(gc, np, gpio_spec, flags); |
863fbf49 AV |
72 | if (ret < 0) |
73 | goto err1; | |
74 | ||
a19e3da5 | 75 | ret += gc->base; |
863fbf49 | 76 | err1: |
a19e3da5 | 77 | of_node_put(gpio_np); |
863fbf49 AV |
78 | err0: |
79 | pr_debug("%s exited with status %d\n", __func__, ret); | |
80 | return ret; | |
81 | } | |
b908b53d | 82 | EXPORT_SYMBOL(of_get_gpio_flags); |
863fbf49 | 83 | |
74982092 AV |
84 | /** |
85 | * of_gpio_count - Count GPIOs for a device | |
86 | * @np: device node to count GPIOs for | |
87 | * | |
88 | * The function returns the count of GPIOs specified for a node. | |
89 | * | |
90 | * Note that the empty GPIO specifiers counts too. For example, | |
91 | * | |
92 | * gpios = <0 | |
93 | * &pio1 1 2 | |
94 | * 0 | |
95 | * &pio2 3 4>; | |
96 | * | |
97 | * defines four GPIOs (so this function will return 4), two of which | |
98 | * are not specified. | |
99 | */ | |
100 | unsigned int of_gpio_count(struct device_node *np) | |
101 | { | |
102 | unsigned int cnt = 0; | |
103 | ||
104 | do { | |
105 | int ret; | |
106 | ||
107 | ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", | |
108 | cnt, NULL, NULL); | |
109 | /* A hole in the gpios = <> counts anyway. */ | |
110 | if (ret < 0 && ret != -EEXIST) | |
111 | break; | |
112 | } while (++cnt); | |
113 | ||
114 | return cnt; | |
115 | } | |
116 | EXPORT_SYMBOL(of_gpio_count); | |
117 | ||
863fbf49 | 118 | /** |
b908b53d | 119 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags |
a19e3da5 | 120 | * @gc: pointer to the gpio_chip structure |
863fbf49 AV |
121 | * @np: device node of the GPIO chip |
122 | * @gpio_spec: gpio specifier as found in the device tree | |
b908b53d | 123 | * @flags: a flags pointer to fill in |
863fbf49 AV |
124 | * |
125 | * This is simple translation function, suitable for the most 1:1 mapped | |
126 | * gpio chips. This function performs only one sanity check: whether gpio | |
127 | * is less than ngpios (that is specified in the gpio_chip). | |
128 | */ | |
391c970c AV |
129 | static int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np, |
130 | const void *gpio_spec, u32 *flags) | |
863fbf49 | 131 | { |
33714881 JK |
132 | const __be32 *gpio = gpio_spec; |
133 | const u32 n = be32_to_cpup(gpio); | |
863fbf49 | 134 | |
b908b53d AV |
135 | /* |
136 | * We're discouraging gpio_cells < 2, since that way you'll have to | |
137 | * write your own xlate function (that will have to retrive the GPIO | |
138 | * number and the flags from a single gpio cell -- this is possible, | |
139 | * but not recommended). | |
140 | */ | |
a19e3da5 | 141 | if (gc->of_gpio_n_cells < 2) { |
b908b53d AV |
142 | WARN_ON(1); |
143 | return -EINVAL; | |
144 | } | |
145 | ||
a19e3da5 | 146 | if (n > gc->ngpio) |
863fbf49 AV |
147 | return -EINVAL; |
148 | ||
b908b53d | 149 | if (flags) |
33714881 | 150 | *flags = be32_to_cpu(gpio[1]); |
b908b53d | 151 | |
33714881 | 152 | return n; |
863fbf49 | 153 | } |
863fbf49 | 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 | |
a19e3da5 AV |
164 | * - of_gpio_n_cells |
165 | * - of_xlate callback (optional) | |
863fbf49 AV |
166 | * |
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 | */ | |
174 | int of_mm_gpiochip_add(struct device_node *np, | |
175 | struct of_mm_gpio_chip *mm_gc) | |
176 | { | |
177 | int ret = -ENOMEM; | |
a19e3da5 | 178 | struct gpio_chip *gc = &mm_gc->gc; |
863fbf49 AV |
179 | |
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 | ||
21451155 | 188 | gc->base = -1; |
863fbf49 | 189 | |
863fbf49 AV |
190 | if (mm_gc->save_regs) |
191 | mm_gc->save_regs(mm_gc); | |
192 | ||
a19e3da5 | 193 | mm_gc->gc.of_node = np; |
863fbf49 AV |
194 | |
195 | ret = gpiochip_add(gc); | |
196 | if (ret) | |
197 | goto err2; | |
198 | ||
863fbf49 AV |
199 | pr_debug("%s: registered as generic GPIO chip, base is %d\n", |
200 | np->full_name, gc->base); | |
201 | return 0; | |
202 | err2: | |
863fbf49 AV |
203 | iounmap(mm_gc->regs); |
204 | err1: | |
205 | kfree(gc->label); | |
206 | err0: | |
207 | pr_err("%s: GPIO chip registration failed with status %d\n", | |
208 | np->full_name, ret); | |
209 | return ret; | |
210 | } | |
211 | EXPORT_SYMBOL(of_mm_gpiochip_add); | |
594fa265 | 212 | |
391c970c AV |
213 | void of_gpiochip_add(struct gpio_chip *chip) |
214 | { | |
215 | if ((!chip->of_node) && (chip->dev)) | |
216 | chip->of_node = chip->dev->of_node; | |
217 | ||
218 | if (!chip->of_node) | |
219 | return; | |
220 | ||
221 | if (!chip->of_xlate) { | |
222 | chip->of_gpio_n_cells = 2; | |
223 | chip->of_xlate = of_gpio_simple_xlate; | |
224 | } | |
225 | ||
226 | of_node_get(chip->of_node); | |
227 | } | |
228 | ||
229 | void of_gpiochip_remove(struct gpio_chip *chip) | |
230 | { | |
231 | if (chip->of_node) | |
232 | of_node_put(chip->of_node); | |
233 | } | |
234 | ||
594fa265 GL |
235 | /* Private function for resolving node pointer to gpio_chip */ |
236 | static int of_gpiochip_is_match(struct gpio_chip *chip, void *data) | |
237 | { | |
238 | return chip->of_node == data; | |
239 | } | |
240 | ||
241 | struct gpio_chip *of_node_to_gpiochip(struct device_node *np) | |
242 | { | |
243 | return gpiochip_find(np, of_gpiochip_is_match); | |
244 | } |