[PATCH v3 3/3] dt-bindings: input: gpio-matrix-keypad: add reduced matrix keypad bindings definition

[<Gireesh.Hiremath@in.bosch.com>]

From: Gireesh Hiremath <Gireesh.Hiremath@in.bosch.com>

Add binding definition for the support of the reduced matrix
keypad driver.

Signed-off-by: Gireesh Hiremath <Gireesh.Hiremath@in.bosch.com>
---
 .../bindings/input/gpio-matrix-keypad.txt     | 96 +++++++++++++++++++
 1 file changed, 96 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt b/Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt
index 570dc10f0cd7..1cedec29505c 100644
--- a/Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt
+++ b/Documentation/devicetree/bindings/input/gpio-matrix-keypad.txt
@@ -1,11 +1,46 @@
 * GPIO driven matrix keypad device tree bindings
 
 GPIO driven matrix keypad is used to interface a SoC with a matrix keypad.
+
+Generic mode:
 The matrix keypad supports multiple row and column lines, a key can be
 placed at each intersection of a unique row and a unique column. The matrix
 keypad can sense a key-press and key-release by means of GPIO lines and
 report the event using GPIO interrupts to the cpu.
 
+Reduced mode:
+The reduced matric keypad supports multiple gpio lines, all gpio lines
+act as row as well as column lines, a key can be placed at each intersection
+of a row number not equal to a column number and they are diagonally
+symmetric.
+
+Example- For 5 gpio lines, possible matrix is 5x5 and maximum possible
+	keys are 10.
+
+	Sample matrix table for 7 buttons and 5 gpio lines
+
+        ------------------------------------------------------
+        |Row\Col |GPIO 0 | GPIO 1 | GPIO 2 | GPIO 3 | GPIO 4 |
+        ------------------------------------------------------
+        | GPIO 0 |  X    | KEY_9  | KEY_2  |   X    | KEY_1  |
+        ------------------------------------------------------
+        | GPIO 1 | KEY_9 |  X     | KEY_6  |   X    |  X     |
+        ------------------------------------------------------
+        | GPIO 2 | KEY_2 | KEY_6  |  X     | KEY_4  | KEY_7  |
+        ------------------------------------------------------
+        | GPIO 3 |  X    |  X     | KEY_4  |  X     | KEY_8  |
+        ------------------------------------------------------
+        | GPIO 4 | KEY_1 |  X     | KEY_7  | KEY_8  |  X     |
+        ------------------------------------------------------
+        X - invalid key
+        KEY_x - preferred key code
+
+The reduced mode sense a key-press and key-release by polling
+GPIO lines and report the event.
+
+
+Generic mode:
+
 Required Properties:
 - compatible:		Should be "gpio-matrix-keypad"
 - row-gpios:		List of gpios used as row lines. The gpio specifier
@@ -47,3 +82,64 @@ Example:
 				0x0101001C
 				0x0201006C>;
 	};
+
+Reduced mode:
+
+Required Properties:
+- compatible:		Should be "gpio-matrix-keypad-reduced"
+- number-of-buttons:	Number of buttons connected to the keypad controller.
+- line-gpios:		Gpio lines connected to keypad controller.
+			all gpio lines act as row as well as column lines.
+- linux,keymap:		An array of packed 1-cell entries containing the
+			equivalent of row, column and linux key-code.
+			The 32-bit big endian cell is packed as:
+			row << 24 | column << 16 | key-code
+
+Optional Properties:
+- poll-interval-ms:	Time interval between poll.
+- linux,no-autorepeat:	Do no enable autorepeat feature.
+- col-scan-delay-us:	Delay before scanning next active line.
+
+Example:
+        keypad {
+                compatible = "gpio-matrix-keypad-reduced";
+                poll-interval-ms = <10>;
+                col-scan-delay-us = <2>;
+                number-of-buttons = <7>;
+                linux,no-autorepeat;
+                line-gpios = <
+                        &gpio1 24 1     /*gpio_56*/
+                        &gpio1 23 1     /*gpio_55*/
+                        &gpio1 22 1     /*gpio_54*/
+                        &gpio1 20 1     /*gpio_52*/
+                        &gpio1 16 1     /*gpio_48*/
+                >;
+                linux,keymap = <
+                        0x00000000 /* row 0, col 0, KEY_RESERVED */
+                        0x0001000a /* row 0, col 1, KEY_9 */
+                        0x00020003 /* row 0, col 2, KEY_2 */
+                        0x00030000 /* row 0, col 3, KEY_RESERVED */
+                        0x00040002 /* row 0, col 4, KEY_1 */
+                        0x0100000a /* row 1, col 0, KEY_9 */
+                        0x01010000 /* row 1, col 1, KEY_RESERVED */
+                        0x01020007 /* row 1, col 2, KEY_6 */
+                        0x01030000 /* row 1, col 3, KEY_RESERVED */
+                        0x01040000 /* row 1, col 4, KEY_RESERVED */
+                        0x02000003 /* row 2, col 0, KEY_2 */
+                        0x02010007 /* row 2, col 1, KEY_6 */
+                        0x02020000 /* row 2, col 2, KEY_RESERVED */
+                        0x02030005 /* row 2, col 3, KEY_4 */
+                        0x02040008 /* row 2, col 4, KEY_7 */
+                        0x03000000 /* row 3, col 0, KEY_RESERVED */
+                        0x03010000 /* row 3, col 1, KEY_RESERVED */
+                        0x03020005 /* row 3, col 2, KEY_4 */
+                        0x03030000 /* row 3, col 3, KEY_RESERVED */
+                        0x03040009 /* row 3, col 4, KEY_8 */
+                        0x04000002 /* row 4, col 0, KEY_1 */
+                        0x04010000 /* row 4, col 1, KEY_RESERVED */
+                        0x04020008 /* row 4, col 2, KEY_7 */
+                        0x04030009 /* row 4, col 3, KEY_8 */
+                        0x04040000 /* row 4, col 4, KEY_RESERVED */
+                >;
+
+        };
-- 
2.20.1