Add readjoy to read joystick events from userspace

Also fix a bit of formatting in the joystick driver file.

driver/x52joy.c

@@ -221,6 +221,7 @@ static int to_hex(const char c)
     }
     return -1;
 }
+
 static ssize_t set_brightness(struct device *dev, const char *buf,
                               size_t count, u8 target)
 {

user/Makefile

@@ -0,0 +1,10 @@
+
+readjoy: readjoy.c
+	gcc -o $@ $<
+
+all: readjoy
+
+.PHONY: clean
+clean:
+	rm -f readjoy
+

user/readjoy.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <linux/joystick.h>
+
+int main(int argc, char *argv[])
+{
+    struct js_event joy_event;
+    int fd;
+    if (argc != 2) {
+        fprintf(stderr, "Usage: %s /dev/input/jsX\n", argv[0]);
+        return -1;
+    }
+
+    fd = open(argv[1], O_RDONLY);
+    if (!fd) {
+        fprintf(stderr, "Error: Unable to open %s!\n", argv[1]);
+        return -2;
+    }
+
+    for(;;) {
+        if (read(fd, &joy_event, sizeof(joy_event)) != sizeof(joy_event)) {
+            fprintf(stderr, "Error: Unable to read from joystick!\n");
+            return -3;
+        } else {
+            if (joy_event.type & JS_EVENT_INIT) {
+                printf("*");
+            }
+
+            if (joy_event.type & JS_EVENT_BUTTON) {
+                printf("B");
+            } else if (joy_event.type & JS_EVENT_AXIS) {
+                printf("A");
+            } else {
+                printf("?");
+            }
+            printf("%u: %d\n", joy_event.number, joy_event.value);
+        }
+    }
+
+    return 0;
+}