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Release 4.14 tools/gpio/gpio-utils.c

Directory: tools/gpio
/*
 * 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, const char *consumer_label) { struct gpiohandle_request req; char *chrdev_name; int fd; int i; int ret; ret = asprintf(&chrdev_name, "/dev/%s", device_name); if (ret < 0) return -ENOMEM; fd = open(chrdev_name, 0); if (fd == -1) { ret = -errno; fprintf(stderr, "Failed to open %s\n", chrdev_name); goto exit_close_error; } for (i = 0; i < nlines; i++) req.lineoffsets[i] = lines[i]; req.flags = flag; strcpy(req.consumer_label, consumer_label); req.lines = nlines; if (flag & GPIOHANDLE_REQUEST_OUTPUT) memcpy(req.default_values, data, sizeof(req.default_values)); ret = ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &req); if (ret == -1) { ret = -errno; fprintf(stderr, "Failed to issue GET LINEHANDLE IOCTL (%d)\n", ret); } exit_close_error: if (close(fd) == -1) perror("Failed to close GPIO character device file"); free(chrdev_name); return ret < 0 ? ret : req.fd; }

Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang243100.00%1100.00%
Total243100.00%1100.00%

/** * gpiotools_set_values(): Set the value of gpio(s) * @fd: The fd returned by * gpiotools_request_linehandle(). * @data: The array of values want to set. * * Return: On success return 0; * On failure return the errno. */
int gpiotools_set_values(const int fd, struct gpiohandle_data *data) { int ret; ret = ioctl(fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, data); if (ret == -1) { ret = -errno; fprintf(stderr, "Failed to issue %s (%d)\n", "GPIOHANDLE_SET_LINE_VALUES_IOCTL", ret); } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang56100.00%1100.00%
Total56100.00%1100.00%

/** * gpiotools_get_values(): Get the value of gpio(s) * @fd: The fd returned by * gpiotools_request_linehandle(). * @data: The array of values get from hardware. * * Return: On success return 0; * On failure return the errno. */
int gpiotools_get_values(const int fd, struct gpiohandle_data *data) { int ret; ret = ioctl(fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, data); if (ret == -1) { ret = -errno; fprintf(stderr, "Failed to issue %s (%d)\n", "GPIOHANDLE_GET_LINE_VALUES_IOCTL", ret); } return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang56100.00%1100.00%
Total56100.00%1100.00%

/** * gpiotools_release_linehandle(): Release the line(s) of gpiochip * @fd: The fd returned by * gpiotools_request_linehandle(). * * Return: On success return 0; * On failure return the errno. */
int gpiotools_release_linehandle(const int fd) { int ret; ret = close(fd); if (ret == -1) { perror("Failed to close GPIO LINEHANDLE device file"); ret = -errno; } return ret; }

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PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang41100.00%1100.00%
Total41100.00%1100.00%

/** * gpiotools_get(): Get value from specific line * @device_name: The name of gpiochip without prefix "/dev/", * such as "gpiochip0" * @line: number of line, such as 2. * * Return: On success return 0; * On failure return the errno. */
int gpiotools_get(const char *device_name, unsigned int line) { struct gpiohandle_data data; unsigned int lines[] = {line}; gpiotools_gets(device_name, lines, 1, &data); return data.values[0]; }

Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang47100.00%1100.00%
Total47100.00%1100.00%

/** * gpiotools_gets(): Get values from specific lines. * @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. * @data: The array of values get from gpiochip. * * Return: On success return 0; * On failure return the errno. */
int gpiotools_gets(const char *device_name, unsigned int *lines, unsigned int nlines, struct gpiohandle_data *data) { int fd; int ret; int ret_close; ret = gpiotools_request_linehandle(device_name, lines, nlines, GPIOHANDLE_REQUEST_INPUT, data, COMSUMER); if (ret < 0) return ret; fd = ret; ret = gpiotools_get_values(fd, data); ret_close = gpiotools_release_linehandle(fd); return ret < 0 ? ret : ret_close; }

Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang88100.00%1100.00%
Total88100.00%1100.00%

/** * gpiotools_set(): Set value to specific line * @device_name: The name of gpiochip without prefix "/dev/", * such as "gpiochip0" * @line: number of line, such as 2. * @value: The value of gpio, must be 0(low) or 1(high). * * Return: On success return 0; * On failure return the errno. */
int gpiotools_set(const char *device_name, unsigned int line, unsigned int value) { struct gpiohandle_data data; unsigned int lines[] = {line}; data.values[0] = value; return gpiotools_sets(device_name, lines, 1, &data); }

Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang53100.00%1100.00%
Total53100.00%1100.00%

/** * gpiotools_sets(): Set values to specific lines. * @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. * @data: The array of values set to gpiochip, must be * 0(low) or 1(high). * * Return: On success return 0; * On failure return the errno. */
int gpiotools_sets(const char *device_name, unsigned int *lines, unsigned int nlines, struct gpiohandle_data *data) { int ret; ret = gpiotools_request_linehandle(device_name, lines, nlines, GPIOHANDLE_REQUEST_OUTPUT, data, COMSUMER); if (ret < 0) return ret; return gpiotools_release_linehandle(ret); }

Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang59100.00%1100.00%
Total59100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Bamvor Jian Zhang68499.56%150.00%
Linus Walleij30.44%150.00%
Total687100.00%2100.00%
Directory: tools/gpio
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