-----Original Message-----
From: Devshatwar, Nikhil
Sent: Thursday, January 08, 2015 7:43 PM
To: devicetree-compiler@vger.kernel.org; devicetree@vger.kernel.org;
devicetree-spec@vger.kernel.org; linux-omap@vger.kernel.org
Cc: Devshatwar, Nikhil
Subject: [PATCH] dtc: parser: Add label while overriding nodes

Current device tree compiler allows to define multiple labels when
defining the device node the first time. Typically device nodes are
defined in DTSI files. Now these nodes can be overriden for updating
some of the properties. Typically, device nodes are overridden in DTS
files.

When working with adapter boards, most of the time adapter board can
fit to multiple base boards. But depending on which base board it is
connected to, the devices on the adapter board would be children of
different devices.

e.g. On dra7-evm.dts, i2c2 is exported for expansion connector whereas
on dra72-evm.dts, i2c5 is exported for expansion connector.
This causes a problem when writing a generic device tree file for the
adapter board. Because, you cannot know wheather all the devices on
adpter board are present on i2c or i2c5.

The problem can be solved by adding a common label (e.g. i2cexp) in
both of the DTS files when overriding the device nodes for i2c2 or
i2c5.
This way, generic adapter board file would override the i2cexp. And
depending on which base board you use the adpter board, all the devices
are automatically added for correct device nodes.

Change-Id: I3ad7247a79baed7268a91fc691360aece73d6d1b
Signed-off-by: Nikhil Devshatwar <redacted>
---
 scripts/dtc/dtc-parser.y |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/scripts/dtc/dtc-parser.y b/scripts/dtc/dtc-parser.y index

f412460..d9ed3b7 100644

--- a/scripts/dtc/dtc-parser.y
+++ b/scripts/dtc/dtc-parser.y

@@ -145,6 +145,18 @@ devicetree:
 		{
 			$$ = merge_nodes($1, $3);
 		}
+
+	| devicetree DT_LABEL DT_REF nodedef
+		{
+			struct node *target = get_node_by_ref($1, $3);
+
+			add_label(&target->labels, $2);
+			if (target)
+				merge_nodes(target, $4);
+			else
+				print_error("label or path, '%s', not found",

$2);
+			$$ = $1;
+		}
 	| devicetree DT_REF nodedef
 		{
 			struct node *target = get_node_by_ref($1, $2);
--
1.7.9.5