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/of_gpio.h>
22 * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API
23 * @np: device node to get GPIO from
24 * @index: index of the GPIO
25 * @flags: a flags pointer to fill in
27 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
28 * value on the error condition. If @flags is not NULL the function also fills
29 * in flags for the GPIO.
31 int of_get_gpio_flags(struct device_node
*np
, int index
,
32 enum of_gpio_flags
*flags
)
35 struct device_node
*gc
;
36 struct of_gpio_chip
*of_gc
= NULL
;
38 const void *gpio_spec
;
39 const u32
*gpio_cells
;
41 ret
= of_parse_phandles_with_args(np
, "gpios", "#gpio-cells", index
,
44 pr_debug("%s: can't parse gpios property\n", __func__
);
50 pr_debug("%s: gpio controller %s isn't registered\n",
51 np
->full_name
, gc
->full_name
);
56 gpio_cells
= of_get_property(gc
, "#gpio-cells", &size
);
57 if (!gpio_cells
|| size
!= sizeof(*gpio_cells
) ||
58 *gpio_cells
!= of_gc
->gpio_cells
) {
59 pr_debug("%s: wrong #gpio-cells for %s\n",
60 np
->full_name
, gc
->full_name
);
65 /* .xlate might decide to not fill in the flags, so clear it. */
69 ret
= of_gc
->xlate(of_gc
, np
, gpio_spec
, flags
);
73 ret
+= of_gc
->gc
.base
;
77 pr_debug("%s exited with status %d\n", __func__
, ret
);
80 EXPORT_SYMBOL(of_get_gpio_flags
);
83 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
84 * @of_gc: pointer to the of_gpio_chip structure
85 * @np: device node of the GPIO chip
86 * @gpio_spec: gpio specifier as found in the device tree
87 * @flags: a flags pointer to fill in
89 * This is simple translation function, suitable for the most 1:1 mapped
90 * gpio chips. This function performs only one sanity check: whether gpio
91 * is less than ngpios (that is specified in the gpio_chip).
93 int of_gpio_simple_xlate(struct of_gpio_chip
*of_gc
, struct device_node
*np
,
94 const void *gpio_spec
, enum of_gpio_flags
*flags
)
96 const u32
*gpio
= gpio_spec
;
99 * We're discouraging gpio_cells < 2, since that way you'll have to
100 * write your own xlate function (that will have to retrive the GPIO
101 * number and the flags from a single gpio cell -- this is possible,
102 * but not recommended).
104 if (of_gc
->gpio_cells
< 2) {
109 if (*gpio
> of_gc
->gc
.ngpio
)
117 EXPORT_SYMBOL(of_gpio_simple_xlate
);
120 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
121 * @np: device node of the GPIO chip
122 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
124 * To use this function you should allocate and fill mm_gc with:
126 * 1) In the gpio_chip structure:
127 * - all the callbacks
129 * 2) In the of_gpio_chip structure:
131 * - xlate callback (optional)
133 * 3) In the of_mm_gpio_chip structure:
134 * - save_regs callback (optional)
136 * If succeeded, this function will map bank's memory and will
137 * do all necessary work for you. Then you'll able to use .regs
138 * to manage GPIOs from the callbacks.
140 int of_mm_gpiochip_add(struct device_node
*np
,
141 struct of_mm_gpio_chip
*mm_gc
)
144 struct of_gpio_chip
*of_gc
= &mm_gc
->of_gc
;
145 struct gpio_chip
*gc
= &of_gc
->gc
;
147 gc
->label
= kstrdup(np
->full_name
, GFP_KERNEL
);
151 mm_gc
->regs
= of_iomap(np
, 0);
158 of_gc
->xlate
= of_gpio_simple_xlate
;
160 if (mm_gc
->save_regs
)
161 mm_gc
->save_regs(mm_gc
);
165 ret
= gpiochip_add(gc
);
169 /* We don't want to lose the node and its ->data */
172 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
173 np
->full_name
, gc
->base
);
177 iounmap(mm_gc
->regs
);
181 pr_err("%s: GPIO chip registration failed with status %d\n",
185 EXPORT_SYMBOL(of_mm_gpiochip_add
);