From 7baed996272cd3c889a5ab714c2b3391703f75f1 Mon Sep 17 00:00:00 2001
From: guowenxue <guowenxue@gmail.com>
Date: Sat, 23 Jan 2021 19:44:10 +0800
Subject: [PATCH] Add gpiod.c for libgpiod output sample code
---
modules/c/led.c | 2
modules/c/gpiod.c | 91 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+), 1 deletions(-)
diff --git a/modules/c/gpiod.c b/modules/c/gpiod.c
new file mode 100644
index 0000000..3ad04bd
--- /dev/null
+++ b/modules/c/gpiod.c
@@ -0,0 +1,91 @@
+/*********************************************************************************
+ * Copyright: (C) 2021 LingYun IoT System Studio
+ * All rights reserved.
+ *
+ * Filename: gpiod.c
+ * Description: This file is used to control a pin GPIO output by libgpiod
+ *
+ * pi@raspberrypi:~ $ gpio readall show BCM and wPi pinmap
+ *
+ *
+ * Version: 1.0.0(2021/01/23)
+ * Author: Guo Wenxue <guowenxue@gmail.com>
+ * ChangeLog: 1, Release initial version on "2021/01/23 12:13:26"
+ *
+ ********************************************************************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <string.h>
+#include <time.h>
+#include <errno.h>
+
+#include <gpiod.h>
+
+void gpiod_ctxless_cb(void *data)
+{
+ sleep(1);
+}
+
+int main(int argc, char *argv[])
+{
+ struct gpiod_chip *chip;
+ struct gpiod_line *line;
+ int bcm_pin;
+ int level;
+
+ if( argc != 3 )
+ {
+ printf(" Usage: sudo %s [BCM Pin number] [1/0]\n", argv[0]);
+ printf("example, turn BCM Pin #6 lowlevel : sudo %s 6 0\n", argv[0]);
+ printf("example, turn BCM Pin #6 highlevel: sudo %s 6 1\n", argv[0]);
+ }
+
+ bcm_pin = atoi(argv[1]);
+ level = atoi(argv[2]);
+#if 0
+ if( level )
+ gpiod_ctxless_set_value("gpiochip0", bcm_pin, 1, false, "led", gpiod_ctxless_cb, NULL);
+ else
+ gpiod_ctxless_set_value("gpiochip0", bcm_pin, 0, false, "led", gpiod_ctxless_cb, NULL);
+#else
+ chip = gpiod_chip_open_by_name("gpiochip0");
+ if( !chip )
+ {
+ printf("gpiod open chip failure, maybe you need running as root\n");
+ exit(1);
+ }
+
+ line = gpiod_chip_get_line(chip, bcm_pin);
+ if( !line )
+ {
+ printf("gpiod get line for BCM pin [#%d] failure\n", bcm_pin);
+ exit(1);
+ }
+
+ gpiod_line_request_output(line, "led", 1);
+
+ printf("set BCM pin #%d as %s level\n", bcm_pin, level?"high":"low");
+
+ if( level )
+ {
+ gpiod_line_set_value(line, 1);
+ }
+ else
+ {
+ gpiod_line_set_value(line, 0);
+ }
+
+ sleep(1); /* must add sleep here, or it will not take effect */
+
+ gpiod_line_release(line);
+ gpiod_chip_close(chip);
+#endif
+
+ return 0;
+}
+
+
diff --git a/modules/c/led.c b/modules/c/led.c
index 2bf3df8..5ef2c0c 100644
--- a/modules/c/led.c
+++ b/modules/c/led.c
@@ -91,7 +91,7 @@
#include <gpiod.h>
-#if 1 /* Use libgpiod lowlevel API */
+#if 0 /* Use libgpiod lowlevel API */
struct gpiod_chip* chip;
--
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