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, 6 insertions, 3 deletions

diff --git a/Documentation/devicetree/bindings/input/lpc32xx-key.txt b/Documentation/devicetree/bindings/input/lpc32xx-key.txt
index 31afd5014c48..bcf62f856358 100644
--- a/Documentation/devicetree/bindings/input/lpc32xx-key.txt
+++ b/Documentation/devicetree/bindings/input/lpc32xx-key.txt
@@ -1,19 +1,22 @@
 NXP LPC32xx Key Scan Interface
 
+This binding is based on the matrix-keymap binding with the following
+changes:
+
 Required Properties:
 - compatible: Should be "nxp,lpc3220-key"
 - reg: Physical base address of the controller and length of memory mapped
   region.
 - interrupts: The interrupt number to the cpu.
-- keypad,num-rows: Number of rows and columns, e.g. 1: 1x1, 6: 6x6
-- keypad,num-columns: Must be equal to keypad,num-rows since LPC32xx only
-  supports square matrices
 - nxp,debounce-delay-ms: Debounce delay in ms
 - nxp,scan-delay-ms: Repeated scan period in ms
 - linux,keymap: the key-code to be reported when the key is pressed
   and released, see also
   Documentation/devicetree/bindings/input/matrix-keymap.txt
 
+Note: keypad,num-rows and keypad,num-columns are required, and must be equal
+since LPC32xx only supports square matrices
+
 Example:
 
 	key@40050000 {