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>
18 #include <linux/gpio.h>
20 #include <linux/of_address.h>
21 #include <linux/of_gpio.h>
22 #include <linux/slab.h>
24 /* Private data structure for of_gpiochip_is_match */
26 enum of_gpio_flags
*flags
;
27 struct of_phandle_args gpiospec
;
32 /* Private function for resolving node pointer to gpio_chip */
33 static int of_gpiochip_find_and_xlate(struct gpio_chip
*gc
, void *data
)
35 struct gg_data
*gg_data
= data
;
38 if ((gc
->of_node
!= gg_data
->gpiospec
.np
) ||
39 (gc
->of_gpio_n_cells
!= gg_data
->gpiospec
.args_count
) ||
43 ret
= gc
->of_xlate(gc
, &gg_data
->gpiospec
, gg_data
->flags
);
47 gg_data
->out_gpio
= ret
+ gc
->base
;
52 * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
53 * @np: device node to get GPIO from
54 * @propname: property name containing gpio specifier(s)
55 * @index: index of the GPIO
56 * @flags: a flags pointer to fill in
58 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
59 * value on the error condition. If @flags is not NULL the function also fills
60 * in flags for the GPIO.
62 int of_get_named_gpio_flags(struct device_node
*np
, const char *propname
,
63 int index
, enum of_gpio_flags
*flags
)
65 struct gg_data gg_data
= { .flags
= flags
, .out_gpio
= -ENODEV
};
68 /* .of_xlate might decide to not fill in the flags, so clear it. */
72 ret
= of_parse_phandle_with_args(np
, propname
, "#gpio-cells", index
,
75 pr_debug("%s: can't parse gpios property\n", __func__
);
79 gpiochip_find(&gg_data
, of_gpiochip_find_and_xlate
);
81 of_node_put(gg_data
.gpiospec
.np
);
82 pr_debug("%s exited with status %d\n", __func__
, ret
);
83 return gg_data
.out_gpio
;
85 EXPORT_SYMBOL(of_get_named_gpio_flags
);
88 * of_gpio_named_count - Count GPIOs for a device
89 * @np: device node to count GPIOs for
90 * @propname: property name containing gpio specifier(s)
92 * The function returns the count of GPIOs specified for a node.
94 * Note that the empty GPIO specifiers counts too. For example,
101 * defines four GPIOs (so this function will return 4), two of which
104 unsigned int of_gpio_named_count(struct device_node
*np
, const char* propname
)
106 unsigned int cnt
= 0;
111 ret
= of_parse_phandle_with_args(np
, propname
, "#gpio-cells",
113 /* A hole in the gpios = <> counts anyway. */
114 if (ret
< 0 && ret
!= -EEXIST
)
120 EXPORT_SYMBOL(of_gpio_named_count
);
123 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
124 * @gc: pointer to the gpio_chip structure
125 * @np: device node of the GPIO chip
126 * @gpio_spec: gpio specifier as found in the device tree
127 * @flags: a flags pointer to fill in
129 * This is simple translation function, suitable for the most 1:1 mapped
130 * gpio chips. This function performs only one sanity check: whether gpio
131 * is less than ngpios (that is specified in the gpio_chip).
133 int of_gpio_simple_xlate(struct gpio_chip
*gc
,
134 const struct of_phandle_args
*gpiospec
, u32
*flags
)
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) {
147 if (WARN_ON(gpiospec
->args_count
< gc
->of_gpio_n_cells
))
150 if (gpiospec
->args
[0] >= gc
->ngpio
)
154 *flags
= gpiospec
->args
[1];
156 return gpiospec
->args
[0];
158 EXPORT_SYMBOL(of_gpio_simple_xlate
);
161 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
162 * @np: device node of the GPIO chip
163 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
165 * To use this function you should allocate and fill mm_gc with:
167 * 1) In the gpio_chip structure:
168 * - all the callbacks
170 * - of_xlate callback (optional)
172 * 3) In the of_mm_gpio_chip structure:
173 * - save_regs callback (optional)
175 * If succeeded, this function will map bank's memory and will
176 * do all necessary work for you. Then you'll able to use .regs
177 * to manage GPIOs from the callbacks.
179 int of_mm_gpiochip_add(struct device_node
*np
,
180 struct of_mm_gpio_chip
*mm_gc
)
183 struct gpio_chip
*gc
= &mm_gc
->gc
;
185 gc
->label
= kstrdup(np
->full_name
, GFP_KERNEL
);
189 mm_gc
->regs
= of_iomap(np
, 0);
195 if (mm_gc
->save_regs
)
196 mm_gc
->save_regs(mm_gc
);
198 mm_gc
->gc
.of_node
= np
;
200 ret
= gpiochip_add(gc
);
206 iounmap(mm_gc
->regs
);
210 pr_err("%s: GPIO chip registration failed with status %d\n",
214 EXPORT_SYMBOL(of_mm_gpiochip_add
);
216 void of_gpiochip_add(struct gpio_chip
*chip
)
218 if ((!chip
->of_node
) && (chip
->dev
))
219 chip
->of_node
= chip
->dev
->of_node
;
224 if (!chip
->of_xlate
) {
225 chip
->of_gpio_n_cells
= 2;
226 chip
->of_xlate
= of_gpio_simple_xlate
;
229 of_node_get(chip
->of_node
);
232 void of_gpiochip_remove(struct gpio_chip
*chip
)
235 of_node_put(chip
->of_node
);