tools/gpio: add gpio basic opereations
Add basic gpio operations. User could get/set gpio value for specific line of gpiochip. Reference "tools/gpio/gpio-hammer.c" or "tools/testing/selftest/gpio/gpio-mockup-chardev.c" for how to use it. Signed-off-by: Bamvor Jian Zhang <bamvor.zhangjian@linaro.org> Reviewed-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Bamvor Jian Zhang
Linus Walleij
parent
26a48c4cc2
commit
e1acec0e75
2 changed files with 272 additions and 0 deletions
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@ -2,10 +2,266 @@
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* GPIO tools - helpers library for the GPIO tools
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*
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* Copyright (C) 2015 Linus Walleij
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* Copyright (C) 2016 Bamvor Jian Zhang
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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#include <fcntl.h>
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#include <getopt.h>
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#include <sys/ioctl.h>
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#include <linux/gpio.h>
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#include "gpio-utils.h"
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#define COMSUMER "gpio-utils"
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/**
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* doc: Operation of gpio
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*
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* Provide the api of gpiochip for chardev interface. There are two
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* types of api. The first one provide as same function as each
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* ioctl, including request and release for lines of gpio, read/write
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* the value of gpio. If the user want to do lots of read and write of
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* lines of gpio, user should use this type of api.
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*
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* The second one provide the easy to use api for user. Each of the
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* following api will request gpio lines, do the operation and then
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* release these lines.
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*/
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/**
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* gpiotools_request_linehandle() - request gpio lines in a gpiochip
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* @device_name: The name of gpiochip without prefix "/dev/",
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* such as "gpiochip0"
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* @lines: An array desired lines, specified by offset
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* index for the associated GPIO device.
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* @nline: The number of lines to request.
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* @flag: The new flag for requsted gpio. Reference
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* "linux/gpio.h" for the meaning of flag.
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* @data: Default value will be set to gpio when flag is
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* GPIOHANDLE_REQUEST_OUTPUT.
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* @consumer_label: The name of consumer, such as "sysfs",
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* "powerkey". This is useful for other users to
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* know who is using.
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*
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* Request gpio lines through the ioctl provided by chardev. User
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* could call gpiotools_set_values() and gpiotools_get_values() to
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* read and write respectively through the returned fd. Call
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* gpiotools_release_linehandle() to release these lines after that.
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*
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* Return: On success return the fd;
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* On failure return the errno.
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*/
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int gpiotools_request_linehandle(const char *device_name, unsigned int *lines,
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unsigned int nlines, unsigned int flag,
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struct gpiohandle_data *data,
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const char *consumer_label)
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{
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struct gpiohandle_request req;
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char *chrdev_name;
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int fd;
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int i;
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int ret;
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ret = asprintf(&chrdev_name, "/dev/%s", device_name);
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if (ret < 0)
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return -ENOMEM;
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fd = open(chrdev_name, 0);
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if (fd == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to open %s\n", chrdev_name);
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goto exit_close_error;
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}
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for (i = 0; i < nlines; i++)
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req.lineoffsets[i] = lines[i];
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req.flags = flag;
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strcpy(req.consumer_label, consumer_label);
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req.lines = nlines;
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if (flag & GPIOHANDLE_REQUEST_OUTPUT)
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memcpy(req.default_values, data, sizeof(req.default_values));
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ret = ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &req);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue GET LINEHANDLE IOCTL (%d)\n",
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ret);
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}
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exit_close_error:
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if (close(fd) == -1)
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perror("Failed to close GPIO character device file");
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free(chrdev_name);
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return ret < 0 ? ret : req.fd;
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}
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/**
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* gpiotools_set_values(): Set the value of gpio(s)
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* @fd: The fd returned by
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* gpiotools_request_linehandle().
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* @data: The array of values want to set.
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*
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* Return: On success return 0;
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* On failure return the errno.
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*/
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int gpiotools_set_values(const int fd, struct gpiohandle_data *data)
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{
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int ret;
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ret = ioctl(fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, data);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue %s (%d)\n",
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"GPIOHANDLE_SET_LINE_VALUES_IOCTL", ret);
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}
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return ret;
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}
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/**
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* gpiotools_get_values(): Get the value of gpio(s)
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* @fd: The fd returned by
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* gpiotools_request_linehandle().
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* @data: The array of values get from hardware.
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*
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* Return: On success return 0;
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* On failure return the errno.
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*/
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int gpiotools_get_values(const int fd, struct gpiohandle_data *data)
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{
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int ret;
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ret = ioctl(fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, data);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue %s (%d)\n",
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"GPIOHANDLE_GET_LINE_VALUES_IOCTL", ret);
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}
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return ret;
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}
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/**
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* gpiotools_release_linehandle(): Release the line(s) of gpiochip
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* @fd: The fd returned by
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* gpiotools_request_linehandle().
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*
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* Return: On success return 0;
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* On failure return the errno.
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*/
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int gpiotools_release_linehandle(const int fd)
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{
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int ret;
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ret = close(fd);
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if (ret == -1) {
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perror("Failed to close GPIO LINEHANDLE device file");
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ret = -errno;
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}
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return ret;
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}
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/**
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* gpiotools_get(): Get value from specific line
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* @device_name: The name of gpiochip without prefix "/dev/",
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* such as "gpiochip0"
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* @line: number of line, such as 2.
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*
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* Return: On success return 0;
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* On failure return the errno.
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*/
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int gpiotools_get(const char *device_name, unsigned int line)
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{
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struct gpiohandle_data data;
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unsigned int lines[] = {line};
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gpiotools_gets(device_name, lines, 1, &data);
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return data.values[0];
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}
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/**
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* gpiotools_gets(): Get values from specific lines.
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* @device_name: The name of gpiochip without prefix "/dev/",
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* such as "gpiochip0".
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* @lines: An array desired lines, specified by offset
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* index for the associated GPIO device.
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* @nline: The number of lines to request.
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* @data: The array of values get from gpiochip.
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*
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* Return: On success return 0;
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* On failure return the errno.
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*/
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int gpiotools_gets(const char *device_name, unsigned int *lines,
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unsigned int nlines, struct gpiohandle_data *data)
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{
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int fd;
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int ret;
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int ret_close;
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ret = gpiotools_request_linehandle(device_name, lines, nlines,
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GPIOHANDLE_REQUEST_INPUT, data,
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COMSUMER);
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if (ret < 0)
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return ret;
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fd = ret;
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ret = gpiotools_get_values(fd, data);
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ret_close = gpiotools_release_linehandle(fd);
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return ret < 0 ? ret : ret_close;
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}
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/**
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* gpiotools_set(): Set value to specific line
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* @device_name: The name of gpiochip without prefix "/dev/",
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* such as "gpiochip0"
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* @line: number of line, such as 2.
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* @value: The value of gpio, must be 0(low) or 1(high).
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*
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* Return: On success return 0;
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* On failure return the errno.
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*/
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int gpiotools_set(const char *device_name, unsigned int line,
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unsigned int value)
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{
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struct gpiohandle_data data;
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unsigned int lines[] = {line};
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data.values[0] = value;
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return gpiotools_sets(device_name, lines, 1, &data);
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}
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/**
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* gpiotools_sets(): Set values to specific lines.
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* @device_name: The name of gpiochip without prefix "/dev/",
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* such as "gpiochip0".
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* @lines: An array desired lines, specified by offset
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* index for the associated GPIO device.
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* @nline: The number of lines to request.
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* @data: The array of values set to gpiochip, must be
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* 0(low) or 1(high).
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*
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* Return: On success return 0;
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* On failure return the errno.
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*/
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int gpiotools_sets(const char *device_name, unsigned int *lines,
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unsigned int nlines, struct gpiohandle_data *data)
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{
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int ret;
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ret = gpiotools_request_linehandle(device_name, lines, nlines,
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GPIOHANDLE_REQUEST_OUTPUT, data,
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COMSUMER);
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if (ret < 0)
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return ret;
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return gpiotools_release_linehandle(ret);
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}
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@ -24,4 +24,20 @@ static inline int check_prefix(const char *str, const char *prefix)
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strncmp(str, prefix, strlen(prefix)) == 0;
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}
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int gpiotools_request_linehandle(const char *device_name, unsigned int *lines,
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unsigned int nlines, unsigned int flag,
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struct gpiohandle_data *data,
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const char *consumer_label);
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int gpiotools_set_values(const int fd, struct gpiohandle_data *data);
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int gpiotools_get_values(const int fd, struct gpiohandle_data *data);
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int gpiotools_release_linehandle(const int fd);
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int gpiotools_get(const char *device_name, unsigned int line);
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int gpiotools_gets(const char *device_name, unsigned int *lines,
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unsigned int nlines, struct gpiohandle_data *data);
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int gpiotools_set(const char *device_name, unsigned int line,
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unsigned int value);
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int gpiotools_sets(const char *device_name, unsigned int *lines,
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unsigned int nlines, struct gpiohandle_data *data);
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#endif /* _GPIO_UTILS_H_ */
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