2 * OF helpers for the GPIO API
4 * Copyright (c) 2007-2008 MontaVista Software, Inc.
6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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.
14 #include <linux/device.h>
15 #include <linux/errno.h>
16 #include <linux/module.h>
19 #include <linux/of_address.h>
20 #include <linux/of_gpio.h>
21 #include <linux/slab.h>
24 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
25 * @np: device node to get GPIO from
26 * @propname: property name containing gpio specifier(s)
27 * @index: index of the GPIO
28 * @flags: a flags pointer to fill in
30 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
31 * value on the error condition. If @flags is not NULL the function also fills
32 * in flags for the GPIO.
34 int of_get_named_gpio_flags(struct device_node
*np
, const char *propname
,
35 int index
, enum of_gpio_flags
*flags
)
39 struct of_phandle_args gpiospec
;
41 ret
= of_parse_phandle_with_args(np
, propname
, "#gpio-cells", index
,
44 pr_debug("%s: can't parse gpios property\n", __func__
);
48 gc
= of_node_to_gpiochip(gpiospec
.np
);
50 pr_debug("%s: gpio controller %s isn't registered\n",
51 np
->full_name
, gpiospec
.np
->full_name
);
56 if (gpiospec
.args_count
!= gc
->of_gpio_n_cells
) {
57 pr_debug("%s: wrong #gpio-cells for %s\n",
58 np
->full_name
, gpiospec
.np
->full_name
);
63 /* .xlate might decide to not fill in the flags, so clear it. */
67 ret
= gc
->of_xlate(gc
, &gpiospec
, flags
);
73 of_node_put(gpiospec
.np
);
75 pr_debug("%s exited with status %d\n", __func__
, ret
);
78 EXPORT_SYMBOL(of_get_named_gpio_flags
);
81 * of_gpio_named_count - Count GPIOs for a device
82 * @np: device node to count GPIOs for
83 * @propname: property name containing gpio specifier(s)
85 * The function returns the count of GPIOs specified for a node.
87 * Note that the empty GPIO specifiers counts too. For example,
94 * defines four GPIOs (so this function will return 4), two of which
97 unsigned int of_gpio_named_count(struct device_node
*np
, const char* propname
)
104 ret
= of_parse_phandle_with_args(np
, propname
, "#gpio-cells",
106 /* A hole in the gpios = <> counts anyway. */
107 if (ret
< 0 && ret
!= -EEXIST
)
113 EXPORT_SYMBOL(of_gpio_named_count
);
116 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
117 * @gc: pointer to the gpio_chip structure
118 * @np: device node of the GPIO chip
119 * @gpio_spec: gpio specifier as found in the device tree
120 * @flags: a flags pointer to fill in
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).
126 int of_gpio_simple_xlate(struct gpio_chip
*gc
,
127 const struct of_phandle_args
*gpiospec
, u32
*flags
)
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).
135 if (gc
->of_gpio_n_cells
< 2) {
140 if (WARN_ON(gpiospec
->args_count
< gc
->of_gpio_n_cells
))
143 if (gpiospec
->args
[0] >= gc
->ngpio
)
147 *flags
= gpiospec
->args
[1];
149 return gpiospec
->args
[0];
151 EXPORT_SYMBOL(of_gpio_simple_xlate
);
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
158 * To use this function you should allocate and fill mm_gc with:
160 * 1) In the gpio_chip structure:
161 * - all the callbacks
163 * - of_xlate callback (optional)
165 * 3) In the of_mm_gpio_chip structure:
166 * - save_regs callback (optional)
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.
172 int of_mm_gpiochip_add(struct device_node
*np
,
173 struct of_mm_gpio_chip
*mm_gc
)
176 struct gpio_chip
*gc
= &mm_gc
->gc
;
178 gc
->label
= kstrdup(np
->full_name
, GFP_KERNEL
);
182 mm_gc
->regs
= of_iomap(np
, 0);
188 if (mm_gc
->save_regs
)
189 mm_gc
->save_regs(mm_gc
);
191 mm_gc
->gc
.of_node
= np
;
193 ret
= gpiochip_add(gc
);
199 iounmap(mm_gc
->regs
);
203 pr_err("%s: GPIO chip registration failed with status %d\n",
207 EXPORT_SYMBOL(of_mm_gpiochip_add
);
209 void of_gpiochip_add(struct gpio_chip
*chip
)
211 if ((!chip
->of_node
) && (chip
->dev
))
212 chip
->of_node
= chip
->dev
->of_node
;
217 if (!chip
->of_xlate
) {
218 chip
->of_gpio_n_cells
= 2;
219 chip
->of_xlate
= of_gpio_simple_xlate
;
222 of_node_get(chip
->of_node
);
225 void of_gpiochip_remove(struct gpio_chip
*chip
)
228 of_node_put(chip
->of_node
);
231 /* Private function for resolving node pointer to gpio_chip */
232 static int of_gpiochip_is_match(struct gpio_chip
*chip
, const void *data
)
234 return chip
->of_node
== data
;
237 struct gpio_chip
*of_node_to_gpiochip(struct device_node
*np
)
239 return gpiochip_find(np
, of_gpiochip_is_match
);