// SPDX-License-Identifier: GPL-2.0-only
/*
* GPIO tools - helpers library for the GPIO tools
*
* Copyright (C) 2015 Linus Walleij
* Copyright (C) 2016 Bamvor Jian Zhang
*/
#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 CONSUMER "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_line() - 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.
* @num_lines: The number of lines to request.
* @config: The new config for requested gpio. Reference
* "linux/gpio.h" for config details.
* @consumer: 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_line() to release these lines after that.
*
* Return: On success return the fd;
* On failure return the errno.
*/
int gpiotools_request_line(const char *device_name, unsigned int *lines,
unsigned int num_lines,
struct gpio_v2_line_config *config,
const char *consumer)
{
struct gpio_v2_line_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, %s\n",
chrdev_name, strerror(errno));
goto exit_free_name;
}
memset(&req, 0, sizeof(req));
for (i = 0; i < num_lines; i++)
req.offsets[i] = lines[i];
req.config = *config;
strcpy(req.consumer, consumer);
req.num_lines = num_lines;
ret = ioctl(fd, GPIO_V2_GET_LINE_IOCTL, &req);
if (ret == -1) {
ret = -errno;
fprintf(stderr, "Failed to issue %s (%d), %s\n",
"GPIO_GET_LINE_IOCTL", ret, strerror(errno));
}
if (close(fd) == -1)
perror("Failed to close GPIO character device file");
exit_free_name:
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_line().
* @values: 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 gpio_v2_line_values *values)
{
int ret;
ret = ioctl(fd, GPIO_V2_LINE_SET_VALUES_IOCTL, values);
if (ret == -1) {
ret = -errno;
fprintf(stderr, "Failed to issue %s (%d), %s\n",
"GPIOHANDLE_SET_LINE_VALUES_IOCTL", ret,
strerror(errno));
}
return ret;
}
/**
* gpiotools_get_values() - Get the value of gpio(s)
* @fd: The fd returned by
* gpiotools_request_line().
* @values: 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 gpio_v2_line_values *values)
{
int ret;
ret = ioctl(fd, GPIO_V2_LINE_GET_VALUES_IOCTL, values);
if (ret == -1) {
ret = -errno;
fprintf(stderr, "Failed to issue %s (%d), %s\n",
"GPIOHANDLE_GET_LINE_VALUES_IOCTL", ret,
strerror(errno));
}
return ret;
}
/**
* gpiotools_release_line() - Release the line(s) of gpiochip
* @fd: The fd returned by
* gpiotools_request_line().
*
* Return: On success return 0;
* On failure return the errno.
*/
int gpiotools_release_line(const int fd)
{
int ret;
ret = close(fd);
if (ret == -1) {
perror("Failed to close GPIO LINE 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)
{
int ret;
unsigned int value;
unsigned int lines[] = {line};
ret = gpiotools_gets(device_name, lines, 1, &value);
if (ret)
return ret;
return value;
}
/**
* 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.
* @num_lines: The number of lines to request.
* @values: 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 num_lines, unsigned int *values)
{
int fd, i;
int ret;
int ret_close;
struct gpio_v2_line_config config;
struct gpio_v2_line_values lv;
memset(&config, 0, sizeof(config));
config.flags = GPIO_V2_LINE_FLAG_INPUT;
ret = gpiotools_request_line(device_name, lines, num_lines,
&config, CONSUMER);
if (ret < 0)
return ret;
fd = ret;
for (i = 0; i < num_lines; i++)
gpiotools_set_bit(&lv.mask, i);
ret = gpiotools_get_values(fd, &lv);
if (!ret)
for (i = 0; i < num_lines; i++)
values[i] = gpiotools_test_bit(lv.bits, i);
ret_close = gpiotools_release_line(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)
{
unsigned int lines[] = {line};
return gpiotools_sets(device_name, lines, 1, &value);
}
/**
* 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.
* @num_lines: The number of lines to request.
* @values: 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 num_lines, unsigned int *values)
{
int ret, i;
struct gpio_v2_line_config config;
memset(&config, 0, sizeof(config));
config.flags = GPIO_V2_LINE_FLAG_OUTPUT;
config.num_attrs = 1;
config.attrs[0].attr.id = GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES;
for (i = 0; i < num_lines; i++) {
gpiotools_set_bit(&config.attrs[0].mask, i);
gpiotools_assign_bit(&config.attrs[0].attr.values,
i, values[i]);
}
ret = gpiotools_request_line(device_name, lines, num_lines,
&config, CONSUMER);
if (ret < 0)
return ret;
return gpiotools_release_line(ret);
}
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