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/kernel.h>
15 #include <linux/errno.h>
18 #include <linux/slab.h>
19 #include <linux/of_gpio.h>
23 * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API
24 * @np: device node to get GPIO from
25 * @index: index of the GPIO
26 * @flags: a flags pointer to fill in
28 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
29 * value on the error condition. If @flags is not NULL the function also fills
30 * in flags for the GPIO.
32 int of_get_gpio_flags(struct device_node
*np
, int index
,
33 enum of_gpio_flags
*flags
)
36 struct device_node
*gpio_np
;
39 const void *gpio_spec
;
40 const __be32
*gpio_cells
;
42 ret
= of_parse_phandles_with_args(np
, "gpios", "#gpio-cells", index
,
43 &gpio_np
, &gpio_spec
);
45 pr_debug("%s: can't parse gpios property\n", __func__
);
49 gc
= of_node_to_gpiochip(gpio_np
);
51 pr_debug("%s: gpio controller %s isn't registered\n",
52 np
->full_name
, gpio_np
->full_name
);
57 gpio_cells
= of_get_property(gpio_np
, "#gpio-cells", &size
);
58 if (!gpio_cells
|| size
!= sizeof(*gpio_cells
) ||
59 be32_to_cpup(gpio_cells
) != gc
->of_gpio_n_cells
) {
60 pr_debug("%s: wrong #gpio-cells for %s\n",
61 np
->full_name
, gpio_np
->full_name
);
66 /* .xlate might decide to not fill in the flags, so clear it. */
70 ret
= gc
->of_xlate(gc
, np
, gpio_spec
, flags
);
78 pr_debug("%s exited with status %d\n", __func__
, ret
);
81 EXPORT_SYMBOL(of_get_gpio_flags
);
84 * of_gpio_count - Count GPIOs for a device
85 * @np: device node to count GPIOs for
87 * The function returns the count of GPIOs specified for a node.
89 * Note that the empty GPIO specifiers counts too. For example,
96 * defines four GPIOs (so this function will return 4), two of which
99 unsigned int of_gpio_count(struct device_node
*np
)
101 unsigned int cnt
= 0;
106 ret
= of_parse_phandles_with_args(np
, "gpios", "#gpio-cells",
108 /* A hole in the gpios = <> counts anyway. */
109 if (ret
< 0 && ret
!= -EEXIST
)
115 EXPORT_SYMBOL(of_gpio_count
);
118 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
119 * @gc: pointer to the gpio_chip structure
120 * @np: device node of the GPIO chip
121 * @gpio_spec: gpio specifier as found in the device tree
122 * @flags: a flags pointer to fill in
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).
128 static int of_gpio_simple_xlate(struct gpio_chip
*gc
, struct device_node
*np
,
129 const void *gpio_spec
, u32
*flags
)
131 const __be32
*gpio
= gpio_spec
;
132 const u32 n
= be32_to_cpup(gpio
);
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).
140 if (gc
->of_gpio_n_cells
< 2) {
149 *flags
= be32_to_cpu(gpio
[1]);
155 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
156 * @np: device node of the GPIO chip
157 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
159 * To use this function you should allocate and fill mm_gc with:
161 * 1) In the gpio_chip structure:
162 * - all the callbacks
164 * - of_xlate callback (optional)
166 * 3) In the of_mm_gpio_chip structure:
167 * - save_regs callback (optional)
169 * If succeeded, this function will map bank's memory and will
170 * do all necessary work for you. Then you'll able to use .regs
171 * to manage GPIOs from the callbacks.
173 int of_mm_gpiochip_add(struct device_node
*np
,
174 struct of_mm_gpio_chip
*mm_gc
)
177 struct gpio_chip
*gc
= &mm_gc
->gc
;
179 gc
->label
= kstrdup(np
->full_name
, GFP_KERNEL
);
183 mm_gc
->regs
= of_iomap(np
, 0);
189 if (mm_gc
->save_regs
)
190 mm_gc
->save_regs(mm_gc
);
192 mm_gc
->gc
.of_node
= np
;
194 ret
= gpiochip_add(gc
);
198 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
199 np
->full_name
, gc
->base
);
202 iounmap(mm_gc
->regs
);
206 pr_err("%s: GPIO chip registration failed with status %d\n",
210 EXPORT_SYMBOL(of_mm_gpiochip_add
);
212 void of_gpiochip_add(struct gpio_chip
*chip
)
214 if ((!chip
->of_node
) && (chip
->dev
))
215 chip
->of_node
= chip
->dev
->of_node
;
220 if (!chip
->of_xlate
) {
221 chip
->of_gpio_n_cells
= 2;
222 chip
->of_xlate
= of_gpio_simple_xlate
;
225 of_node_get(chip
->of_node
);
228 void of_gpiochip_remove(struct gpio_chip
*chip
)
231 of_node_put(chip
->of_node
);
234 /* Private function for resolving node pointer to gpio_chip */
235 static int of_gpiochip_is_match(struct gpio_chip
*chip
, void *data
)
237 return chip
->of_node
== data
;
240 struct gpio_chip
*of_node_to_gpiochip(struct device_node
*np
)
242 return gpiochip_find(np
, of_gpiochip_is_match
);