input: Extend matrix-keypad device tree binding

Some matrix keypad drivers can support different numbers of rows and
columns. Add a generic binding for these.

Implementation note:

In order to implement this binding in the kernel, we will need to modify
matrix_keypad_() to look up the number of rows and cols in
the keymap. Perhaps this could be done by passing 0 for these parameters?
Many of the parameters can already be set to NULL. Ick.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 8 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/matrix-keymap.txt b/Documentation/devicetree/bindings/input/matrix-keymap.txt
index 3cd8b98ccd2d..c54919fad17e 100644
--- a/Documentation/devicetree/bindings/input/matrix-keymap.txt
+++ b/Documentation/devicetree/bindings/input/matrix-keymap.txt
@@ -9,6 +9,12 @@ Required properties:
 	row << 24 | column << 16 | key-code
 
 Optional properties:
+Properties for the number of rows and columns are optional because some
+drivers will use fixed values for these.
+- keypad,num-rows: Number of row lines connected to the keypad controller.
+- keypad,num-columns: Number of column lines connected to the keypad
+  controller.
+
 Some users of this binding might choose to specify secondary keymaps for
 cases where there is a modifier key such as a Fn key. Proposed names
 for said properties are "linux,fn-keymap" or with another descriptive
@@ -17,3 +23,5 @@ word for the modifier other from "Fn".
 Example:
 	linux,keymap = < 0x00030012
 			 0x0102003a >;
+	keypad,num-rows = <2>;
+	keypad,num-columns = <8>;