HID: samples/hidraw: make it possible to select device

Makefile that can actually build the example, and allow selecting device to
work on.

Signed-off-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

samples/hidraw/Makefile

@@ -8,3 +8,5 @@ hostprogs-y := hid-example
 always := $(hostprogs-y)
 
 HOSTCFLAGS_hid-example.o += -I$(objtree)/usr/include
+
+all: hid-example

samples/hidraw/hid-example.c

@@ -46,10 +46,14 @@ int main(int argc, char **argv)
 	char buf[256];
 	struct hidraw_report_descriptor rpt_desc;
 	struct hidraw_devinfo info;
+	char *device = "/dev/hidraw0";
+
+	if (argc > 1)
+		device = argv[1];
 
 	/* Open the Device with non-blocking reads. In real life,
 	   don't use a hard coded path; use libudev instead. */
-	fd = open("/dev/hidraw0", O_RDWR|O_NONBLOCK);
+	fd = open(device, O_RDWR|O_NONBLOCK);
 
 	if (fd < 0) {
 		perror("Unable to open device");