vsprintf: Add %p extension "%pOF" for device tree
90% of the usage of device node's full_name is printing it out in a
kernel message. However, storing the full path for every node is
wasteful and redundant. With a custom format specifier, we can generate
the full path at run-time and eventually remove the full path from every
node.
For instance typical use is:
pr_info("Frobbing node %s\n", node->full_name);
Which can be written now as:
pr_info("Frobbing node %pOF\n", node);
'%pO' is the base specifier to represent kobjects with '%pOF'
representing struct device_node. Currently, struct device_node is the
only supported type of kobject.
More fine-grained control of formatting includes printing the name,
flags, path-spec name and others, explained in the documentation entry.
Originally written by Pantelis, but pretty much rewrote the core
function using existing string/number functions. The 2 passes were
unnecessary and have been removed. Also, updated the checkpatch.pl
check. The unittest code was written by Grant Likely.
Signed-off-by: Pantelis Antoniou <pantelis.antoniou@konsulko.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/Documentation/printk-formats.txt b/Documentation/printk-formats.txt
index 5962949..619cdff 100644
--- a/Documentation/printk-formats.txt
+++ b/Documentation/printk-formats.txt
@@ -275,6 +275,42 @@
Passed by reference.
+kobjects:
+ %pO
+
+ Base specifier for kobject based structs. Must be followed with
+ character for specific type of kobject as listed below:
+
+ Device tree nodes:
+
+ %pOF[fnpPcCF]
+
+ For printing device tree nodes. The optional arguments are:
+ f device node full_name
+ n device node name
+ p device node phandle
+ P device node path spec (name + @unit)
+ F device node flags
+ c major compatible string
+ C full compatible string
+ Without any arguments prints full_name (same as %pOFf)
+ The separator when using multiple arguments is ':'
+
+ Examples:
+
+ %pOF /foo/bar@0 - Node full name
+ %pOFf /foo/bar@0 - Same as above
+ %pOFfp /foo/bar@0:10 - Node full name + phandle
+ %pOFfcF /foo/bar@0:foo,device:--P- - Node full name +
+ major compatible string +
+ node flags
+ D - dynamic
+ d - detached
+ P - Populated
+ B - Populated bus
+
+ Passed by reference.
+
struct clk:
%pC pll1
