From be59ddb43fbf039ed0bc848ac56b7f72f7a619c8 Mon Sep 17 00:00:00 2001
From: John Ogness <john.ogness@linutronix.de>
Date: Fri, 15 Feb 2019 11:07:10 +0106
Subject: [PATCH 5/7] hello: add led toggling via chardev ioctl

Compile userspace application with:

$ gcc -Wall -Werror hello-led.c -ohello-led

Signed-off-by: John Ogness <john.ogness@linutronix.de>
---
 hello-led.c | 38 ++++++++++++++++++++++++++++++++++++++
 hello.c     | 22 ++++++++++++++++++++++
 hello.h     |  7 +++++++
 3 files changed, 67 insertions(+)
 create mode 100644 hello-led.c
 create mode 100644 hello.h

diff --git a/hello-led.c b/hello-led.c
new file mode 100644
index 0000000..43230cd
--- /dev/null
+++ b/hello-led.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include "hello.h"
+
+int main(int argc, char *argv[])
+{
+	int fd;
+
+	if (argc != 3) {
+		fprintf(stderr, "usage: %s <device> <led>\n", argv[0]);
+		return 1;
+	}
+
+	fd = open(argv[1], O_RDWR);
+	if (fd < 0) {
+		fprintf(stderr, "open() failed: %s\n", strerror(errno));
+		return 1;
+	}
+
+	if (strcmp(argv[2], "heartbeat") == 0)
+		ioctl(fd, HELLO_IOCTL_TOGGLE_LED, 0);
+	else if (strcmp(argv[2], "net") == 0)
+		ioctl(fd, HELLO_IOCTL_TOGGLE_LED, 1);
+	else if (strcmp(argv[2], "disk") == 0)
+		ioctl(fd, HELLO_IOCTL_TOGGLE_LED, 2);
+	else
+		fprintf(stderr, "unknown led\n");
+
+	close(fd);
+
+	return 0;
+}
diff --git a/hello.c b/hello.c
index f664121..c42c75f 100644
--- a/hello.c
+++ b/hello.c
@@ -7,6 +7,7 @@
 #include <linux/device.h>
 #include <linux/pci.h>
 #include <linux/cdev.h>
+#include "hello.h"
 
 struct hello_dev {
 	struct device *dev;
@@ -95,12 +96,33 @@ static ssize_t hello_write(struct file *f, const char __user *u, size_t s,
 	return s;
 }
 
+static long hello_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+	struct hello_dev *hello = f->private_data;
+	u32 val;
+
+	dev_info(hello->dev, "%s: cmd=%u arg=%lu\n", __func__, cmd, arg);
+
+	switch (cmd) {
+	case HELLO_IOCTL_TOGGLE_LED:
+		val = arg;
+		if (val >= 0 && val <= 2)
+			toggle_led(hello, val);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static const struct file_operations hello_fops = {
 	.owner = THIS_MODULE,
 	.open = hello_open,
 	.release = hello_release,
 	.read = hello_read,
 	.write = hello_write,
+	.unlocked_ioctl = hello_ioctl,
 };
 
 static int hello_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
diff --git a/hello.h b/hello.h
new file mode 100644
index 0000000..cb172d9
--- /dev/null
+++ b/hello.h
@@ -0,0 +1,7 @@
+#ifndef HELLO_H
+#define HELLO_H
+
+#define HELLO_BASE		0x9F
+#define HELLO_IOCTL_TOGGLE_LED	_IOW(HELLO_BASE, 0x00, unsigned int)
+
+#endif /* HELLO_H */
-- 
2.11.0