From b9b74e88028f81e7b169a5e168102138e8c2c46c Mon Sep 17 00:00:00 2001
From: yzrh <yzrh@noema.org>
Date: Sat, 10 Oct 2020 17:16:14 +0000
Subject: Initial commit.

---
 src/gpio.c | 194 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 194 insertions(+)
 create mode 100644 src/gpio.c

(limited to 'src/gpio.c')

diff --git a/src/gpio.c b/src/gpio.c
new file mode 100644
index 0000000..9d4cde1
--- /dev/null
+++ b/src/gpio.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2019-2020, yzrh <yzrh@noema.org>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "gpio.h"
+
+#ifdef __FreeBSD__
+
+int
+gpio_config(int pin, int direction, int interrupt)
+{
+	int ret;
+	int fd = open("/dev/gpioc0", O_RDWR);
+
+	if (fd == -1) {
+		fprintf(stderr, "GPIO configuration failure\n");
+		return 1;
+	}
+
+	struct gpio_pin pin_req = {
+		.gp_pin = pin,
+		.gp_caps = interrupt,
+		.gp_flags = direction
+	};
+
+	ret = ioctl(fd, GPIOSETCONFIG, &pin_req) == 0 ? 0 : 1;
+	close(fd);
+	return ret;
+}
+
+int
+gpio_write(int pin, int value)
+{
+	int ret;
+	int fd = open("/dev/gpioc0", O_RDWR);
+
+	if (fd == -1) {
+		fprintf(stderr, "GPIO output failure\n");
+		return 1;
+	}
+
+	struct gpio_req req = {
+		.gp_pin = pin,
+		.gp_value = value
+	};
+
+	ret = ioctl(fd, GPIOSET, &req) == 0 ? 0 : 1;
+	close(fd);
+	return ret;
+}
+
+int
+gpio_read(int pin)
+{
+	int fd = open("/dev/gpioc0", O_RDWR);
+
+	if (fd == -1) {
+		fprintf(stderr, "GPIO input failure\n");
+		return 1;
+	}
+
+	struct gpio_req req = {
+		.gp_pin = pin
+	};
+
+	ioctl(fd, GPIOGET, &req);
+
+	close(fd);
+	return req.gp_value;
+}
+
+#elif __linux__
+
+int
+gpio_export(int pin)
+{
+	int export = open("/sys/class/gpio/export", O_RDWR);
+
+	if (export == -1) {
+		fprintf(stderr, "GPIO export failure\n");
+		return 1;
+	}
+
+	char buf[3];
+	int buf_size = snprintf(buf, 3, "%d", pin);
+	write(export, buf, buf_size);
+
+	close(export);
+	return 0;
+}
+
+int
+gpio_unexport(int pin)
+{
+	int unexport = open("/sys/class/gpio/unexport", O_RDWR);
+
+	if (unexport == -1) {
+		fprintf(stderr, "GPIO unexport failure\n");
+		return 1;
+	}
+
+	char buf[3];
+	int buf_size = snprintf(buf, 3, "%d", pin);
+	write(unexport, buf, buf_size);
+
+	close(unexport);
+	return 0;
+}
+
+int
+gpio_config(int pin, int direction, int interrupt)
+{
+	char path[33];
+	snprintf(path, 33, "/sys/class/gpio/gpio%d/direction", pin);
+
+	int config = open(path, O_RDWR);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO configuration failure\n");
+		return 1;
+	}
+
+	char buf[8];
+	int buf_size = snprintf(buf, 8, "%s", direction == 0 ? "in" : "out");
+	write(config, buf, buf_size);
+
+	close(config);
+
+	snprintf(path, 33, "/sys/class/gpio/gpio%d/edge", pin);
+
+	config = open(path, O_RDWR);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO configuration failure\n");
+		return 1;
+	}
+
+	buf_size = snprintf(buf, 8, "%s",
+		interrupt == 0 ? "falling" : "rising");
+	write(config, buf, buf_size);
+
+	close(config);
+	return 0;
+}
+
+int
+gpio_write(int pin, int value)
+{
+	char path[29];
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", pin);
+
+	int config = open(path, O_RDWR);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO output failure\n");
+		return 1;
+	}
+
+	char buf[2];
+	int buf_size = snprintf(buf, 2, "%d", value);
+	write(config, buf, buf_size);
+
+	close(config);
+	return 0;
+}
+
+int
+gpio_read(int pin)
+{
+	char path[29];
+	snprintf(path, 29, "/sys/class/gpio/gpio%d/value", pin);
+
+	int config = open(path, O_RDONLY);
+
+	if (config == -1) {
+		fprintf(stderr, "GPIO input failure\n");
+		return 1;
+	}
+
+	char buf[2];
+	read(config, buf, 2);
+
+	close(config);
+	return atoi(buf);
+}
+
+#endif /* __FreeBSD__ */
-- 
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