42 lines
1.8 KiB
C
42 lines
1.8 KiB
C
#ifndef _GPIO_DEV_H__
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#define _GPIO_DEV_H__
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/*********************************************************************
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*
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* This Linux kernel header is expanded from the original driver
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* (gpio_dev) by John Crispin. It provides an ioctl based interface to
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* GPIO pins via the /dev/gpio char device and gpiolib within the kernel.
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* The third argument to each ioctl is the GPIO pin number.
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*
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* This driver has been tested with lk 2.6.31 and works. The original
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* driver fails quietly with this version. The protocol is now a bit
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* different: the ioctl(fd, GPIO_REQUEST, <pin>) should be called
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* after the open("/dev/gpio", O_RDWR) to determine if the <pin> is
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* already in use. If the ioctl is successful (i.e. returns 0 for not
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* in use) then the <pin> is claimed by this driver and
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* ioctl(fd, GPIO_FREE, <pin>) should be called prior to close(fd) .
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*
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* See <kernel_source>/Documentation/gpio.txt
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* Note that kernel designers prefer the use of the sysfs gpio interface.
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* This char driver is easier to use from code and faster.
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********************************************************************/
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/* This header can be included in both the user and kernel spaces */
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/* The _IO macro is defined in sys/ioctl.h */
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#define IOC_GPIODEV_MAGIC 'B'
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#define GPIO_GET _IO(IOC_GPIODEV_MAGIC, 10)
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#define GPIO_SET _IO(IOC_GPIODEV_MAGIC, 11)
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#define GPIO_CLEAR _IO(IOC_GPIODEV_MAGIC, 12)
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#define GPIO_DIR_IN _IO(IOC_GPIODEV_MAGIC, 13)
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#define GPIO_DIR_OUT _IO(IOC_GPIODEV_MAGIC, 14)
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/* Sets the direction out and clears the <pin> (low) */
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#define GPIO_DIR_HIGH _IO(IOC_GPIODEV_MAGIC, 15)
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/* Sets the direction out and sets the <pin> (high) */
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#define GPIO_REQUEST _IO(IOC_GPIODEV_MAGIC, 16)
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#define GPIO_FREE _IO(IOC_GPIODEV_MAGIC, 17)
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#define GPIO_CAN_SLEEP _IO(IOC_GPIODEV_MAGIC, 18)
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#endif
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