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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 | /** | |
a6b09191 | 24 | * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API |
863fbf49 | 25 | * @np: device node to get GPIO from |
a6b09191 | 26 | * @propname: property name containing gpio specifier(s) |
863fbf49 | 27 | * @index: index of the GPIO |
b908b53d | 28 | * @flags: a flags pointer to fill in |
863fbf49 AV |
29 | * |
30 | * Returns GPIO number to use with Linux generic GPIO API, or one of the errno | |
b908b53d AV |
31 | * value on the error condition. If @flags is not NULL the function also fills |
32 | * in flags for the GPIO. | |
863fbf49 | 33 | */ |
a6b09191 JB |
34 | int of_get_named_gpio_flags(struct device_node *np, const char *propname, |
35 | int index, enum of_gpio_flags *flags) | |
863fbf49 | 36 | { |
64b60e09 | 37 | int ret; |
a19e3da5 | 38 | struct gpio_chip *gc; |
15c9a0ac | 39 | struct of_phandle_args gpiospec; |
863fbf49 | 40 | |
15c9a0ac GL |
41 | ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index, |
42 | &gpiospec); | |
64b60e09 AV |
43 | if (ret) { |
44 | pr_debug("%s: can't parse gpios property\n", __func__); | |
863fbf49 AV |
45 | goto err0; |
46 | } | |
863fbf49 | 47 | |
15c9a0ac | 48 | gc = of_node_to_gpiochip(gpiospec.np); |
a19e3da5 | 49 | if (!gc) { |
64b60e09 | 50 | pr_debug("%s: gpio controller %s isn't registered\n", |
15c9a0ac | 51 | np->full_name, gpiospec.np->full_name); |
64b60e09 AV |
52 | ret = -ENODEV; |
53 | goto err1; | |
863fbf49 AV |
54 | } |
55 | ||
15c9a0ac | 56 | if (gpiospec.args_count != gc->of_gpio_n_cells) { |
64b60e09 | 57 | pr_debug("%s: wrong #gpio-cells for %s\n", |
15c9a0ac | 58 | np->full_name, gpiospec.np->full_name); |
64b60e09 AV |
59 | ret = -EINVAL; |
60 | goto err1; | |
863fbf49 AV |
61 | } |
62 | ||
b908b53d AV |
63 | /* .xlate might decide to not fill in the flags, so clear it. */ |
64 | if (flags) | |
65 | *flags = 0; | |
66 | ||
15c9a0ac | 67 | ret = gc->of_xlate(gc, &gpiospec, flags); |
863fbf49 AV |
68 | if (ret < 0) |
69 | goto err1; | |
70 | ||
a19e3da5 | 71 | ret += gc->base; |
863fbf49 | 72 | err1: |
15c9a0ac | 73 | of_node_put(gpiospec.np); |
863fbf49 AV |
74 | err0: |
75 | pr_debug("%s exited with status %d\n", __func__, ret); | |
76 | return ret; | |
77 | } | |
a6b09191 | 78 | EXPORT_SYMBOL(of_get_named_gpio_flags); |
863fbf49 | 79 | |
74982092 | 80 | /** |
ff64abef | 81 | * of_gpio_named_count - Count GPIOs for a device |
74982092 | 82 | * @np: device node to count GPIOs for |
ff64abef | 83 | * @propname: property name containing gpio specifier(s) |
74982092 AV |
84 | * |
85 | * The function returns the count of GPIOs specified for a node. | |
86 | * | |
87 | * Note that the empty GPIO specifiers counts too. For example, | |
88 | * | |
89 | * gpios = <0 | |
90 | * &pio1 1 2 | |
91 | * 0 | |
92 | * &pio2 3 4>; | |
93 | * | |
94 | * defines four GPIOs (so this function will return 4), two of which | |
95 | * are not specified. | |
96 | */ | |
ff64abef | 97 | unsigned int of_gpio_named_count(struct device_node *np, const char* propname) |
74982092 AV |
98 | { |
99 | unsigned int cnt = 0; | |
100 | ||
101 | do { | |
102 | int ret; | |
103 | ||
ff64abef | 104 | ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", |
15c9a0ac | 105 | cnt, NULL); |
74982092 AV |
106 | /* A hole in the gpios = <> counts anyway. */ |
107 | if (ret < 0 && ret != -EEXIST) | |
108 | break; | |
109 | } while (++cnt); | |
110 | ||
111 | return cnt; | |
112 | } | |
ff64abef | 113 | EXPORT_SYMBOL(of_gpio_named_count); |
74982092 | 114 | |
863fbf49 | 115 | /** |
b908b53d | 116 | * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags |
a19e3da5 | 117 | * @gc: pointer to the gpio_chip structure |
863fbf49 AV |
118 | * @np: device node of the GPIO chip |
119 | * @gpio_spec: gpio specifier as found in the device tree | |
b908b53d | 120 | * @flags: a flags pointer to fill in |
863fbf49 AV |
121 | * |
122 | * This is simple translation function, suitable for the most 1:1 mapped | |
123 | * gpio chips. This function performs only one sanity check: whether gpio | |
124 | * is less than ngpios (that is specified in the gpio_chip). | |
125 | */ | |
15c9a0ac GL |
126 | int of_gpio_simple_xlate(struct gpio_chip *gc, |
127 | const struct of_phandle_args *gpiospec, u32 *flags) | |
863fbf49 | 128 | { |
b908b53d AV |
129 | /* |
130 | * We're discouraging gpio_cells < 2, since that way you'll have to | |
131 | * write your own xlate function (that will have to retrive the GPIO | |
132 | * number and the flags from a single gpio cell -- this is possible, | |
133 | * but not recommended). | |
134 | */ | |
a19e3da5 | 135 | if (gc->of_gpio_n_cells < 2) { |
b908b53d AV |
136 | WARN_ON(1); |
137 | return -EINVAL; | |
138 | } | |
139 | ||
15c9a0ac GL |
140 | if (WARN_ON(gpiospec->args_count < gc->of_gpio_n_cells)) |
141 | return -EINVAL; | |
142 | ||
143 | if (gpiospec->args[0] > gc->ngpio) | |
863fbf49 AV |
144 | return -EINVAL; |
145 | ||
b908b53d | 146 | if (flags) |
15c9a0ac | 147 | *flags = gpiospec->args[1]; |
b908b53d | 148 | |
15c9a0ac | 149 | return gpiospec->args[0]; |
863fbf49 | 150 | } |
3038bbdf | 151 | EXPORT_SYMBOL(of_gpio_simple_xlate); |
863fbf49 | 152 | |
863fbf49 AV |
153 | /** |
154 | * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank) | |
155 | * @np: device node of the GPIO chip | |
156 | * @mm_gc: pointer to the of_mm_gpio_chip allocated structure | |
157 | * | |
158 | * To use this function you should allocate and fill mm_gc with: | |
159 | * | |
160 | * 1) In the gpio_chip structure: | |
161 | * - all the callbacks | |
a19e3da5 AV |
162 | * - of_gpio_n_cells |
163 | * - of_xlate callback (optional) | |
863fbf49 AV |
164 | * |
165 | * 3) In the of_mm_gpio_chip structure: | |
166 | * - save_regs callback (optional) | |
167 | * | |
168 | * If succeeded, this function will map bank's memory and will | |
169 | * do all necessary work for you. Then you'll able to use .regs | |
170 | * to manage GPIOs from the callbacks. | |
171 | */ | |
172 | int of_mm_gpiochip_add(struct device_node *np, | |
173 | struct of_mm_gpio_chip *mm_gc) | |
174 | { | |
175 | int ret = -ENOMEM; | |
a19e3da5 | 176 | struct gpio_chip *gc = &mm_gc->gc; |
863fbf49 AV |
177 | |
178 | gc->label = kstrdup(np->full_name, GFP_KERNEL); | |
179 | if (!gc->label) | |
180 | goto err0; | |
181 | ||
182 | mm_gc->regs = of_iomap(np, 0); | |
183 | if (!mm_gc->regs) | |
184 | goto err1; | |
185 | ||
21451155 | 186 | gc->base = -1; |
863fbf49 | 187 | |
863fbf49 AV |
188 | if (mm_gc->save_regs) |
189 | mm_gc->save_regs(mm_gc); | |
190 | ||
a19e3da5 | 191 | mm_gc->gc.of_node = np; |
863fbf49 AV |
192 | |
193 | ret = gpiochip_add(gc); | |
194 | if (ret) | |
195 | goto err2; | |
196 | ||
863fbf49 AV |
197 | return 0; |
198 | err2: | |
863fbf49 AV |
199 | iounmap(mm_gc->regs); |
200 | err1: | |
201 | kfree(gc->label); | |
202 | err0: | |
203 | pr_err("%s: GPIO chip registration failed with status %d\n", | |
204 | np->full_name, ret); | |
205 | return ret; | |
206 | } | |
207 | EXPORT_SYMBOL(of_mm_gpiochip_add); | |
594fa265 | 208 | |
391c970c AV |
209 | void of_gpiochip_add(struct gpio_chip *chip) |
210 | { | |
211 | if ((!chip->of_node) && (chip->dev)) | |
212 | chip->of_node = chip->dev->of_node; | |
213 | ||
214 | if (!chip->of_node) | |
215 | return; | |
216 | ||
217 | if (!chip->of_xlate) { | |
218 | chip->of_gpio_n_cells = 2; | |
219 | chip->of_xlate = of_gpio_simple_xlate; | |
220 | } | |
221 | ||
222 | of_node_get(chip->of_node); | |
223 | } | |
224 | ||
225 | void of_gpiochip_remove(struct gpio_chip *chip) | |
226 | { | |
227 | if (chip->of_node) | |
228 | of_node_put(chip->of_node); | |
229 | } | |
230 | ||
594fa265 GL |
231 | /* Private function for resolving node pointer to gpio_chip */ |
232 | static int of_gpiochip_is_match(struct gpio_chip *chip, void *data) | |
233 | { | |
234 | return chip->of_node == data; | |
235 | } | |
236 | ||
237 | struct gpio_chip *of_node_to_gpiochip(struct device_node *np) | |
238 | { | |
239 | return gpiochip_find(np, of_gpiochip_is_match); | |
240 | } |