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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - drivers/of/gpio.c
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_gpio_flags - Get a GPIO number and flags to use with GPIO API
25 * @np: device node to get GPIO from
26 * @index: index of the GPIO
27 * @flags: a flags pointer to fill in
29 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
30 * value on the error condition. If @flags is not NULL the function also fills
31 * in flags for the GPIO.
33 int of_get_gpio_flags(struct device_node
*np
, int index
,
34 enum of_gpio_flags
*flags
)
37 struct device_node
*gpio_np
;
40 const void *gpio_spec
;
41 const __be32
*gpio_cells
;
43 ret
= of_parse_phandles_with_args(np
, "gpios", "#gpio-cells", index
,
44 &gpio_np
, &gpio_spec
);
46 pr_debug("%s: can't parse gpios property\n", __func__
);
50 gc
= of_node_to_gpiochip(gpio_np
);
52 pr_debug("%s: gpio controller %s isn't registered\n",
53 np
->full_name
, gpio_np
->full_name
);
58 gpio_cells
= of_get_property(gpio_np
, "#gpio-cells", &size
);
59 if (!gpio_cells
|| size
!= sizeof(*gpio_cells
) ||
60 be32_to_cpup(gpio_cells
) != gc
->of_gpio_n_cells
) {
61 pr_debug("%s: wrong #gpio-cells for %s\n",
62 np
->full_name
, gpio_np
->full_name
);
67 /* .xlate might decide to not fill in the flags, so clear it. */
71 ret
= gc
->of_xlate(gc
, np
, gpio_spec
, flags
);
79 pr_debug("%s exited with status %d\n", __func__
, ret
);
82 EXPORT_SYMBOL(of_get_gpio_flags
);
85 * of_gpio_count - Count GPIOs for a device
86 * @np: device node to count GPIOs for
88 * The function returns the count of GPIOs specified for a node.
90 * Note that the empty GPIO specifiers counts too. For example,
97 * defines four GPIOs (so this function will return 4), two of which
100 unsigned int of_gpio_count(struct device_node
*np
)
102 unsigned int cnt
= 0;
107 ret
= of_parse_phandles_with_args(np
, "gpios", "#gpio-cells",
109 /* A hole in the gpios = <> counts anyway. */
110 if (ret
< 0 && ret
!= -EEXIST
)
116 EXPORT_SYMBOL(of_gpio_count
);
119 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags
120 * @gc: pointer to the gpio_chip structure
121 * @np: device node of the GPIO chip
122 * @gpio_spec: gpio specifier as found in the device tree
123 * @flags: a flags pointer to fill in
125 * This is simple translation function, suitable for the most 1:1 mapped
126 * gpio chips. This function performs only one sanity check: whether gpio
127 * is less than ngpios (that is specified in the gpio_chip).
129 static int of_gpio_simple_xlate(struct gpio_chip
*gc
, struct device_node
*np
,
130 const void *gpio_spec
, u32
*flags
)
132 const __be32
*gpio
= gpio_spec
;
133 const u32 n
= be32_to_cpup(gpio
);
136 * We're discouraging gpio_cells < 2, since that way you'll have to
137 * write your own xlate function (that will have to retrive the GPIO
138 * number and the flags from a single gpio cell -- this is possible,
139 * but not recommended).
141 if (gc
->of_gpio_n_cells
< 2) {
150 *flags
= be32_to_cpu(gpio
[1]);
156 * of_mm_gpiochip_add - Add memory mapped GPIO chip (bank)
157 * @np: device node of the GPIO chip
158 * @mm_gc: pointer to the of_mm_gpio_chip allocated structure
160 * To use this function you should allocate and fill mm_gc with:
162 * 1) In the gpio_chip structure:
163 * - all the callbacks
165 * - of_xlate callback (optional)
167 * 3) In the of_mm_gpio_chip structure:
168 * - save_regs callback (optional)
170 * If succeeded, this function will map bank's memory and will
171 * do all necessary work for you. Then you'll able to use .regs
172 * to manage GPIOs from the callbacks.
174 int of_mm_gpiochip_add(struct device_node
*np
,
175 struct of_mm_gpio_chip
*mm_gc
)
178 struct gpio_chip
*gc
= &mm_gc
->gc
;
180 gc
->label
= kstrdup(np
->full_name
, GFP_KERNEL
);
184 mm_gc
->regs
= of_iomap(np
, 0);
190 if (mm_gc
->save_regs
)
191 mm_gc
->save_regs(mm_gc
);
193 mm_gc
->gc
.of_node
= np
;
195 ret
= gpiochip_add(gc
);
199 pr_debug("%s: registered as generic GPIO chip, base is %d\n",
200 np
->full_name
, gc
->base
);
203 iounmap(mm_gc
->regs
);
207 pr_err("%s: GPIO chip registration failed with status %d\n",
211 EXPORT_SYMBOL(of_mm_gpiochip_add
);
213 void of_gpiochip_add(struct gpio_chip
*chip
)
215 if ((!chip
->of_node
) && (chip
->dev
))
216 chip
->of_node
= chip
->dev
->of_node
;
221 if (!chip
->of_xlate
) {
222 chip
->of_gpio_n_cells
= 2;
223 chip
->of_xlate
= of_gpio_simple_xlate
;
226 of_node_get(chip
->of_node
);
229 void of_gpiochip_remove(struct gpio_chip
*chip
)
232 of_node_put(chip
->of_node
);
235 /* Private function for resolving node pointer to gpio_chip */
236 static int of_gpiochip_is_match(struct gpio_chip
*chip
, void *data
)
238 return chip
->of_node
== data
;
241 struct gpio_chip
*of_node_to_gpiochip(struct device_node
*np
)
243 return gpiochip_find(np
, of_gpiochip_is_match
);