* 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);
+}
projects / mirror_ubuntu-bionic-kernel.git / commitdiff