Add fdtget utility to read property values from a device tree
This simply utility makes it easy for scripts to read values from the device
tree. It is written in C and uses the same libfdt as the rest of the dtc
package.
What is it for:
- Reading fdt values from scripts
- Extracting fdt information within build systems
- Looking at particular values without having to dump the entire tree
To use it, specify the fdt binary file on command line followed by a list of
node, property pairs. The utility then looks up each node, finds the property
and displays the value.
Each value is printed on a new line.
fdtget tries to guess the type of each property based on its contents. This
is not always reliable, so you can use the -t option to force fdtget to decode
the value as a string, or byte, etc.
To read from stdin, use - as the file.
Usage:
fdtget <options> <dt file> [<node> <property>]...
Options:
-t <type> Type of data
-h Print this help
<type> s=string, i=int, u=unsigned, x=hex
Optional modifier prefix:
hh or b=byte, h=2 byte, l=4 byte (default)
Signed-off-by: Simon Glass <[email protected]>
diff --git a/util.h b/util.h
index 730918e..c8eb45d 100644
--- a/util.h
+++ b/util.h
@@ -140,4 +140,14 @@
*/
int utilfdt_decode_type(const char *fmt, int *type, int *size);
+/*
+ * This is a usage message fragment for the -t option. It is the format
+ * supported by utilfdt_decode_type.
+ */
+
+#define USAGE_TYPE_MSG \
+ "<type>\ts=string, i=int, u=unsigned, x=hex\n" \
+ "\tOptional modifier prefix:\n" \
+ "\t\thh or b=byte, h=2 byte, l=4 byte (default)\n";
+
#endif /* _UTIL_H */
