This is missing at present and the fdtput tool could use a litle more
information than just its help text.
This might be useful for distributions which want to provide a man page.
Signed-off-by: Simon Glass <sjg@xxxxxxxxxxxx>
---
Documentation/manual.txt | 132 ++++++++++++++++++++++++---------------
1 file changed, 82 insertions(+), 50 deletions(-)
diff --git a/Documentation/manual.txt b/Documentation/manual.txt
index dd4d888..90fb9a7 100644
--- a/Documentation/manual.txt
+++ b/Documentation/manual.txt
@@ -44,8 +44,8 @@ The gitweb interface for the upstream respository is:
1.1) Submitting Patches
Patches should be sent to the maintainers:
- David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
- Jon Loeliger <jdl@xxxxxxx>
+ David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
+ Jon Loeliger <jdl@xxxxxxx>
and CCed to <devicetree-compiler@xxxxxxxxxxxxxxx>.
2) Description
@@ -65,7 +65,7 @@ The currently supported Input Formats are:
- "fs" format. A representation equivalent to the output of
/proc/device-tree where nodes are directories and
- properties are files.
+ properties are files.
The currently supported Output Formats are:
@@ -88,62 +88,62 @@ The syntax of the dtc command line is:
Options:
<input_filename>
- The name of the input source file. If no <input_filename>
- or "-" is given, stdin is used.
+ The name of the input source file. If no <input_filename>
+ or "-" is given, stdin is used.
-b <number>
- Set the physical boot cpu.
+ Set the physical boot cpu.
-f
- Force. Try to produce output even if the input tree has errors.
+ Force. Try to produce output even if the input tree has errors.
-h
- Emit a brief usage and help message.
+ Emit a brief usage and help message.
-I <input_format>
- The source input format, as listed above.
+ The source input format, as listed above.
-o <output_filename>
- The name of the generated output file. Use "-" for stdout.
+ The name of the generated output file. Use "-" for stdout.
-O <output_format>
- The generated output format, as listed above.
+ The generated output format, as listed above.
-d <dependency_filename>
- Generate a dependency file during compilation.
+ Generate a dependency file during compilation.
-q
- Quiet: -q suppress warnings, -qq errors, -qqq all
+ Quiet: -q suppress warnings, -qq errors, -qqq all
-R <number>
- Make space for <number> reserve map entries
- Relevant for dtb and asm output only.
+ Make space for <number> reserve map entries
+ Relevant for dtb and asm output only.
-@
- Generates a __symbols__ node at the root node of the resulting blob
- for any node labels used, and for any local references using phandles
- it also generates a __local_fixups__ node that tracks them.
+ Generates a __symbols__ node at the root node of the resulting blob
+ for any node labels used, and for any local references using phandles
+ it also generates a __local_fixups__ node that tracks them.
- When using the /plugin/ tag all unresolved label references to
- be tracked in the __fixups__ node, making dynamic resolution possible.
+ When using the /plugin/ tag all unresolved label references to
+ be tracked in the __fixups__ node, making dynamic resolution possible.
-A
- Generate automatically aliases for all node labels. This is similar to
- the -@ option (the __symbols__ node contain identical information) but
- the semantics are slightly different since no phandles are automatically
- generated for labeled nodes.
+ Generate automatically aliases for all node labels. This is similar to
+ the -@ option (the __symbols__ node contain identical information) but
+ the semantics are slightly different since no phandles are automatically
+ generated for labeled nodes.
-S <bytes>
- Ensure the blob at least <bytes> long, adding additional
- space if needed.
+ Ensure the blob at least <bytes> long, adding additional
+ space if needed.
-v
- Print DTC version and exit.
+ Print DTC version and exit.
-V <output_version>
- Generate output conforming to the given <output_version>.
- By default the most recent version is generated.
- Relevant for dtb and asm output only.
+ Generate output conforming to the given <output_version>.
+ By default the most recent version is generated.
+ Relevant for dtb and asm output only.
The <output_version> defines what version of the "blob" format will be
@@ -163,7 +163,7 @@ Here is a very rough overview of the layout of a DTS source file:
sourcefile: versioninfo plugindecl list_of_memreserve devicetree
memreserve: label 'memreserve' ADDR ADDR ';'
- | label 'memreserve' ADDR '-' ADDR ';'
+ | label 'memreserve' ADDR '-' ADDR ';'
devicetree: '/' nodedef
@@ -177,8 +177,8 @@ Here is a very rough overview of the layout of a DTS source file:
property: label PROPNAME '=' propdata ';'
propdata: STRING
- | '<' list_of_cells '>'
- | '[' list_of_bytes ']'
+ | '<' list_of_cells '>'
+ | '[' list_of_bytes ']'
subnode: label nodename nodedef
@@ -209,19 +209,19 @@ Here are some example property definitions:
- A property containing a 0 terminated string
- property1 = "string_value";
+ property1 = "string_value";
- A property containing a numerical 32-bit hexadecimal value
- property2 = <1234abcd>;
+ property2 = <1234abcd>;
- A property containing 3 numerical 32-bit hexadecimal values
- property3 = <12345678 12345678 deadbeef>;
+ property3 = <12345678 12345678 deadbeef>;
- A property whose content is an arbitrary array of bytes
- property4 = [0a 0b 0c 0d de ea ad be ef];
+ property4 = [0a 0b 0c 0d de ea ad be ef];
Node may contain sub-nodes to obtain a hierarchical structure.
@@ -231,9 +231,9 @@ For example:
"childnode at address". It in turn has a string property
called "childprop".
- childnode@addresss {
- childprop = "hello\n";
- };
+ childnode@addresss {
+ childprop = "hello\n";
+ };
By default, all numeric values are hexadecimal. Alternate bases
@@ -253,19 +253,19 @@ Absolute node path names are also allowed in node references.
In this exmaple, a node is labled "mpic" and then referenced:
mpic: interrupt-controller@40000 {
- ...
+ ...
};
ethernet-phy@3 {
- interrupt-parent = <&mpic>;
- ...
+ interrupt-parent = <&mpic>;
+ ...
};
And used in properties, lables may appear before or after any value:
randomnode {
- prop: string = data: "mystring\n" data_end: ;
- ...
+ prop: string = data: "mystring\n" data_end: ;
+ ...
};
@@ -282,7 +282,7 @@ are described in the kernel documentation in the file
You can find example of code manipulating that format within
the kernel. For example, the file:
- including arch/powerpc/kernel/prom_init.c
+ including arch/powerpc/kernel/prom_init.c
will generate a flattened device-tree from the Open Firmware
representation. Other utilities such as fs2dt, which is part of
@@ -320,19 +320,19 @@ boot_param_header:
u32 size_dt_strings; /* size of the strings block */
/* version 17 fields below */
- u32 size_dt_struct; /* size of the DT structure block */
+ u32 size_dt_struct; /* size of the DT structure block */
};
Along with the constants:
/* Definitions used by the flattened device tree */
#define OF_DT_HEADER 0xd00dfeed /* 4: version,
- 4: total size */
+ 4: total size */
#define OF_DT_BEGIN_NODE 0x1 /* Start node: full name
- */
+ */
#define OF_DT_END_NODE 0x2 /* End node */
#define OF_DT_PROP 0x3 /* Property: name off,
- size, content */
+ size, content */
#define OF_DT_END 0x9
All values in this header are in big endian format, the various
@@ -760,3 +760,35 @@ but with -P was can request that the phandle be decoded and shown as a part:
Note that '-c gpio' is needed to tell fdtget to use the #gpio-cells property
to figure out the number of arguments for each phandle. Without that it cannot
display the arguments correctly.
+
+5 ) fdtput - Write properties to a device tree
+
+The syntax of the fdtput command is:
+
+ fdtput <options> <dt file> <node> <property> [<value>...]
+ fdtput -c <options> <dt file> [<node>...]
+ fdtput -r <options> <dt file> [<node>...]
+ fdtput -d <options> <dt file> <node> [<property>...]
+
+Options are:
+
+ <type> s=string, i=int, u=unsigned, x=hex
+ Optional modifier prefix:
+ hh or b=byte, h=2 byte, l=4 byte (default)
+
+ -c, --create Create nodes if they don't already exist
+ -r, --remove Delete nodes (and any subnodes) if they already exist
+ -d, --delete Delete properties if they already exist
+ -p, --auto-path Automatically create nodes as needed for the node path
+ -t, --type <arg> Type of data
+ -v, --verbose Display each value decoded from command line
+ -h, --help Print this help and exit
+ -V, --version Print version and exit
+
+The option determines which usage is selected and therefore the operation that
+is performed. The first usage adds or updates properties; the rest are used to
+create/delete nodes and delete properties.
+
+For the first usage, the command line arguments are joined together into a
+single value which is written to the property. The -t option is required so
+that fdtput knows how to decode its arguments.
--
2.17.0.441.gb46fe60e1d-goog
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