Commit e1acec0e authored by Bamvor Jian Zhang's avatar Bamvor Jian Zhang Committed by Linus Walleij

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: default avatarBamvor Jian Zhang <bamvor.zhangjian@linaro.org>
Reviewed-by: Michael Welling's avatarMichael Welling <mwelling@ieee.org>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 26a48c4c
......@@ -2,10 +2,266 @@
* 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;
}
/**
* 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;
}
/**
* 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;
}
/**
* 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;
}
/**
* 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];
}
/**
* 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;
}
/**
* 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);
}
/**
* 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);
}
......@@ -24,4 +24,20 @@ static inline int check_prefix(const char *str, const char *prefix)
strncmp(str, prefix, strlen(prefix)) == 0;
}
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);
int gpiotools_set_values(const int fd, struct gpiohandle_data *data);
int gpiotools_get_values(const int fd, struct gpiohandle_data *data);
int gpiotools_release_linehandle(const int fd);
int gpiotools_get(const char *device_name, unsigned int line);
int gpiotools_gets(const char *device_name, unsigned int *lines,
unsigned int nlines, struct gpiohandle_data *data);
int gpiotools_set(const char *device_name, unsigned int line,
unsigned int value);
int gpiotools_sets(const char *device_name, unsigned int *lines,
unsigned int nlines, struct gpiohandle_data *data);
#endif /* _GPIO_UTILS_H_ */
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