This simple utility allows writing of values into a device tree from the
command line. It aimes to be the opposite of fdtget.
What is it for:
- Updating fdt values when a binary blob already exists
(even though source may be available it might be easier to use this
utility rather than sed, etc.)
- Writing machine-specific fdt values within a build system
To use it, specify the fdt binary file on command line followed by the node
and property to set. Then, provide a list of values to put into that
property. Often there will be just one, but fdtput also supports arrays and
string lists.
fdtput does not try to guess the type of the property based on looking at
the arguments. Instead it always assumes that an integer is provided. To
indicate that you want to write a string, use -ts. You can also provide
hex values with -tx.
The command line arguments are joined together into a single value. For
strings, a nul terminator is placed between each string when it is packed
into the property. To avoid this, pass the string as a single argument.
Usage:
fdtput <options> <dt file> <<node> <property> [<value>...]
Options:
-t <type> Type of data
-v Verbose: display each value decoded from command line
-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)
To read from stdin and write to stdout, use - as the file. So you can do:
cat somefile.dtb | fdtput -ts - /node prop "My string value" > newfile.dtb
This commit also adds basic tests to verify the major features.
Signed-off-by: Simon Glass <sjg@chromium.org>
Simon Glass