samples: move watchdog example code from Documentation

Move watchdog examples to samples and remove it from Documentation
Makefile. Create a new Makefile to build watchdog. It can be built
from top level directory or from watchdog directory:

Run make -C samples/watchdog or cd samples/watchdog; make

Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

Documentation/Makefile

@@ -1,2 +1,2 @@
 subdir-y := accounting auxdisplay blackfin \
-	laptops pcmcia watchdog
+	laptops pcmcia

Documentation/watchdog/Makefile

@@ -1 +0,0 @@
-subdir-y := src

Documentation/watchdog/src/Makefile

@@ -1,5 +0,0 @@
-# List of programs to build
-hostprogs-y := watchdog-simple
-
-# Tell kbuild to always build the programs
-always := $(hostprogs-y)

Documentation/watchdog/watchdog-api.txt

@@ -37,7 +37,7 @@ activates as soon as /dev/watchdog is opened and will reboot unless
 the watchdog is pinged within a certain time, this time is called the
 timeout or margin.  The simplest way to ping the watchdog is to write
 some data to the device.  So a very simple watchdog daemon would look
-like this source file:  see Documentation/watchdog/src/watchdog-simple.c
+like this source file:  see samples/watchdog/watchdog-simple.c
 
 A more advanced driver could for example check that a HTTP server is
 still responding before doing the write call to ping the watchdog.

Documentation/watchdog/wdt.txt

@@ -47,4 +47,4 @@ The external event interfaces on the WDT boards are not currently supported.
 Minor numbers are however allocated for it.
 
 
-Example Watchdog Driver:  see Documentation/watchdog/src/watchdog-simple.c
+Example Watchdog Driver:  see samples/watchdog/watchdog-simple.c

samples/watchdog/.gitignore

@@ -0,0 +1 @@
+watchdog-simple

samples/watchdog/Makefile

@@ -0,0 +1,8 @@
+CC := $(CROSS_COMPILE)gcc
+PROGS := watchdog-simple
+
+all: $(PROGS)
+
+clean:
+	rm -fr $(PROGS)
+

samples/watchdog/watchdog-simple.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+int main(void)
+{
+	int fd = open("/dev/watchdog", O_WRONLY);
+	int ret = 0;
+	if (fd == -1) {
+		perror("watchdog");
+		exit(EXIT_FAILURE);
+	}
+	while (1) {
+		ret = write(fd, "\0", 1);
+		if (ret != 1) {
+			ret = -1;
+			break;
+		}
+		sleep(10);
+	}
+	close(fd);
+	return ret;
+}