linux-imx

/*

 * GPIO tools - helpers library for the GPIO tools

 *

 * Copyright (C) 2015 Linus Walleij

 * Copyright (C) 2016 Bamvor Jian Zhang

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 as published by

 * the Free Software Foundation.

 */

​

#include <unistd.h>

#include <stdlib.h>

#include <stdio.h>

#include <errno.h>

#include <string.h>

#include <fcntl.h>

#include <getopt.h>

#include <sys/ioctl.h>

#include <linux/gpio.h>

#include "gpio-utils.h"

​

#define COMSUMER "gpio-utils"

​

/**

 * doc: Operation of gpio

 *

 * Provide the api of gpiochip for chardev interface. There are two

 * types of api.  The first one provide as same function as each

 * ioctl, including request and release for lines of gpio, read/write

 * the value of gpio. If the user want to do lots of read and write of

 * lines of gpio, user should use this type of api.

 *

 * The second one provide the easy to use api for user. Each of the

 * following api will request gpio lines, do the operation and then

 * release these lines.

 */

/**

 * gpiotools_request_linehandle() - request gpio lines in a gpiochip

 * @device_name:    The name of gpiochip without prefix "/dev/",

 *          such as "gpiochip0"

 * @lines:      An array desired lines, specified by offset

 *          index for the associated GPIO device.

 * @nline:      The number of lines to request.

 * @flag:       The new flag for requsted gpio. Reference

 *          "linux/gpio.h" for the meaning of flag.

 * @data:       Default value will be set to gpio when flag is

 *          GPIOHANDLE_REQUEST_OUTPUT.

 * @consumer_label: The name of consumer, such as "sysfs",

 *          "powerkey". This is useful for other users to

 *          know who is using.

 *

 * Request gpio lines through the ioctl provided by chardev. User

 * could call gpiotools_set_values() and gpiotools_get_values() to

 * read and write respectively through the returned fd. Call

 * gpiotools_release_linehandle() to release these lines after that.

 *

 * Return:      On success return the fd;

 *          On failure return the errno.

 */

int gpiotools_request_linehandle(const char *device_name, unsigned int *lines,

                 unsigned int nlines, unsigned int flag,

                 struct gpiohandle_data *data,