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
)
38 struct device_node
*gpio_np
;
41 const void *gpio_spec
;
42 const __be32
*gpio_cells
;
44 ret
= of_parse_phandles_with_args(np
, propname
, "#gpio-cells", index
,
45 &gpio_np
, &gpio_spec
);
47 pr_debug("%s: can't parse gpios property\n", __func__
);
51 gc
= of_node_to_gpiochip(gpio_np
);
53 pr_debug("%s: gpio controller %s isn't registered\n",
54 np
->full_name
, gpio_np
->full_name
);
59 gpio_cells
= of_get_property(gpio_np
, "#gpio-cells", &size
);
60 if (!gpio_cells
|| size
!= sizeof(*gpio_cells
) ||
61 be32_to_cpup(gpio_cells
) != gc
->of_gpio_n_cells
) {
62 pr_debug("%s: wrong #gpio-cells for %s\n",
63 np
->full_name
, gpio_np
->full_name
);
68 /* .xlate might decide to not fill in the flags, so clear it. */
72 ret
= gc
->of_xlate(gc
, np
, gpio_spec
, flags
);
80 pr_debug("%s exited with status %d\n", __func__
, ret
);
83 EXPORT_SYMBOL(of_get_named_gpio_flags
);
86 * of_gpio_count - Count GPIOs for a device
87 * @np: device node to count GPIOs for
89 * The function returns the count of GPIOs specified for a node.
91 * Note that the empty GPIO specifiers counts too. For example,
98 * defines four GPIOs (so this function will return 4), two of which
101 unsigned int of_gpio_count(struct device_node
*np
)
103 unsigned int cnt
= 0;
108 ret
= of_parse_phandles_with_args(np
, "gpios", "#gpio-cells",
110 /* A hole in the gpios = <> counts anyway. */
111 if (ret
< 0 && ret
!= -EEXIST
)
117 EXPORT_SYMBOL(of_gpio_count
);
120 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
121 * @gc: pointer to the gpio_chip structure
122 * @np: device node of the GPIO chip
123 * @gpio_spec: gpio specifier as found in the device tree
124 * @flags: a flags pointer to fill in
126 * This is simple translation function, suitable for the most 1:1 mapped
127 * gpio chips. This function performs only one sanity check: whether gpio
128 * is less than ngpios (that is specified in the gpio_chip).
130 int of_gpio_simple_xlate(struct gpio_chip
*gc
, struct device_node
*np
,
131 const void *gpio_spec
, u32
*flags
)
133 const __be32
*gpio
= gpio_spec
;
134 const u32 n
= be32_to_cpup(gpio
);
137 * We're discouraging gpio_cells < 2, since that way you'll have to
138 * write your own xlate function (that will have to retrive the GPIO
139 * number and the flags from a single gpio cell -- this is possible,
140 * but not recommended).
142 if (gc
->of_gpio_n_cells
< 2) {
151 *flags
= be32_to_cpu(gpio
[1]);
155 EXPORT_SYMBOL(of_gpio_simple_xlate
);
158 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
159 * @np: device node of the GPIO chip
160 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
162 * To use this function you should allocate and fill mm_gc with:
164 * 1) In the gpio_chip structure:
165 * - all the callbacks
167 * - of_xlate callback (optional)
169 * 3) In the of_mm_gpio_chip structure:
170 * - save_regs callback (optional)
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.
176 int of_mm_gpiochip_add(struct device_node
*np
,
177 struct of_mm_gpio_chip
*mm_gc
)
180 struct gpio_chip
*gc
= &mm_gc
->gc
;
182 gc
->label
= kstrdup(np
->full_name
, GFP_KERNEL
);
186 mm_gc
->regs
= of_iomap(np
, 0);
192 if (mm_gc
->save_regs
)
193 mm_gc
->save_regs(mm_gc
);
195 mm_gc
->gc
.of_node
= np
;
197 ret
= gpiochip_add(gc
);
201 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
202 np
->full_name
, gc
->base
);
205 iounmap(mm_gc
->regs
);
209 pr_err("%s: GPIO chip registration failed with status %d\n",
213 EXPORT_SYMBOL(of_mm_gpiochip_add
);
215 void of_gpiochip_add(struct gpio_chip
*chip
)
217 if ((!chip
->of_node
) && (chip
->dev
))
218 chip
->of_node
= chip
->dev
->of_node
;
223 if (!chip
->of_xlate
) {
224 chip
->of_gpio_n_cells
= 2;
225 chip
->of_xlate
= of_gpio_simple_xlate
;
228 of_node_get(chip
->of_node
);
231 void of_gpiochip_remove(struct gpio_chip
*chip
)
234 of_node_put(chip
->of_node
);
237 /* Private function for resolving node pointer to gpio_chip */
238 static int of_gpiochip_is_match(struct gpio_chip
*chip
, void *data
)
240 return chip
->of_node
== data
;
243 struct gpio_chip
*of_node_to_gpiochip(struct device_node
*np
)
245 return gpiochip_find(np
, of_gpiochip_is_match
);