devmem: new applet

diff --git a/include/usage.h b/include/usage.h
index 3c11013..dbef9f6 100644
--- a/include/usage.h
+++ b/include/usage.h
@@ -690,6 +690,15 @@
 #define depmod_trivial_usage NOUSAGE_STR
 #define depmod_full_usage ""
 
+#define devmem_trivial_usage \
+	"ADDRESS [WIDTH [VALUE]]"
+
+#define devmem_full_usage "\n\n" \
+       "Read/write from physical address\n" \
+     "\n	ADDRESS	Address to act upon" \
+     "\n	WIDTH	Width (8/16/...)" \
+     "\n	VALUE	Data to be written" \
+
 #define devfsd_trivial_usage \
        "mntpnt [-v]" USE_DEVFSD_FG_NP("[-fg][-np]")
 #define devfsd_full_usage "\n\n" \