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gpio: add flags to export GPIOs when requesting 

Introduce new flags to automatically export GPIOs when using the convenience
functions gpio_request_one() or gpio_request_array(). This eases support for
custom boards where lots of GPIOs need to be exported for customer
applications.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Wolfram Sang 2011-12-13 18:34:01 +01:00 committed by Grant Likely
parent dd775ae254
commit fc3a1f04f5
3 changed files with 19 additions and 1 deletions
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3
Documentation/gpio.txt
View File

@ -322,6 +322,9 @@ where 'flags' is currently defined to specify the following properties:
* GPIOF_OPEN_DRAIN - gpio pin is open drain type.
* GPIOF_OPEN_SOURCE - gpio pin is open source type.
* GPIOF_EXPORT_DIR_FIXED - export gpio to sysfs, keep direction
* GPIOF_EXPORT_DIR_CHANGEABLE - also export, allow changing direction
since GPIOF_INIT_* are only valid when configured as output, so group valid
combinations as:

12
drivers/gpio/gpiolib.c
View File

@ -1302,8 +1302,18 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
(flags & GPIOF_INIT_HIGH) ? 1 : 0);
if (err)
gpio_free(gpio);
goto free_gpio;
if (flags & GPIOF_EXPORT) {
err = gpio_export(gpio, flags & GPIOF_EXPORT_CHANGEABLE);
if (err)
goto free_gpio;
}
return 0;
free_gpio:
gpio_free(gpio);
return err;
}
EXPORT_SYMBOL_GPL(gpio_request_one);

5
include/linux/gpio.h
View File

@ -20,6 +20,11 @@
/* Gpio pin is open source */
#define GPIOF_OPEN_SOURCE (1 << 3)
#define GPIOF_EXPORT (1 << 2)
#define GPIOF_EXPORT_CHANGEABLE (1 << 3)
#define GPIOF_EXPORT_DIR_FIXED (GPIOF_EXPORT)
#define GPIOF_EXPORT_DIR_CHANGEABLE (GPIOF_EXPORT | GPIOF_EXPORT_CHANGEABLE)
/**
* struct gpio - a structure describing a GPIO with configuration
* @gpio: the GPIO number