CHIP-linux-libre/Documentation/devicetree/bindings/input/brcm,bcm-keypad.txt

* Broadcom Keypad Controller device tree bindings

Broadcom Keypad controller is used to interface a SoC with a matrix-type
keypad device. The keypad controller supports multiple row and column lines.
A key can be placed at each intersection of a unique row and a unique column.
The keypad controller can sense a key-press and key-release and report the
event using a interrupt to the cpu.

This binding is based on the matrix-keymap binding with the following
changes:

keypad,num-rows and keypad,num-columns are required.

Required SoC Specific Properties:
- compatible: should be "brcm,bcm-keypad"

- reg: physical base address of the controller and length of memory mapped
  region.

- interrupts: The interrupt number to the cpu.

Board Specific Properties:
- keypad,num-rows: Number of row lines connected to the keypad
  controller.

- keypad,num-columns: Number of column lines connected to the
  keypad controller.

- col-debounce-filter-period: The debounce period for the Column filter.

	KEYPAD_DEBOUNCE_1_ms	=	0
	KEYPAD_DEBOUNCE_2_ms	=	1
	KEYPAD_DEBOUNCE_4_ms	=	2
	KEYPAD_DEBOUNCE_8_ms	=	3
	KEYPAD_DEBOUNCE_16_ms	=	4
	KEYPAD_DEBOUNCE_32_ms	=	5
	KEYPAD_DEBOUNCE_64_ms	=	6
	KEYPAD_DEBOUNCE_128_ms	=	7

- status-debounce-filter-period: The debounce period for the Status filter.

	KEYPAD_DEBOUNCE_1_ms	=	0
	KEYPAD_DEBOUNCE_2_ms	=	1
	KEYPAD_DEBOUNCE_4_ms	=	2
	KEYPAD_DEBOUNCE_8_ms	=	3
	KEYPAD_DEBOUNCE_16_ms	=	4
	KEYPAD_DEBOUNCE_32_ms	=	5
	KEYPAD_DEBOUNCE_64_ms	=	6
	KEYPAD_DEBOUNCE_128_ms	=	7

- row-output-enabled: An optional property indicating whether the row or
  column is being used as output. If specified the row is being used
  as the output. Else defaults to column.

- pull-up-enabled: An optional property indicating the Keypad scan mode.
  If specified implies the keypad scan pull-up has been enabled.

- autorepeat: Boolean, Enable auto repeat feature of Linux input
	  subsystem (optional).

- linux,keymap: The keymap for keys as described in the binding document
  devicetree/bindings/input/matrix-keymap.txt.

Example:
#include "dt-bindings/input/input.h"

/ {
	keypad: keypad@180ac000 {
		/* Required SoC specific properties */
		compatible = "brcm,bcm-keypad";

		/* Required Board specific properties */
		keypad,num-rows = <5>;
		keypad,num-columns = <5>;
		status = "okay";

		linux,keymap = <MATRIX_KEY(0x00, 0x02, KEY_F) /* key_forward */
		MATRIX_KEY(0x00, 0x03, KEY_HOME) /* key_home */
		MATRIX_KEY(0x00, 0x04, KEY_M) /* key_message */
		MATRIX_KEY(0x01, 0x00, KEY_A) /* key_contacts */
		MATRIX_KEY(0x01, 0x01, KEY_1) /* key_1 */
		MATRIX_KEY(0x01, 0x02, KEY_2) /* key_2 */
		MATRIX_KEY(0x01, 0x03, KEY_3) /* key_3 */
		MATRIX_KEY(0x01, 0x04, KEY_S) /* key_speaker */
		MATRIX_KEY(0x02, 0x00, KEY_P) /* key_phone */
		MATRIX_KEY(0x02, 0x01, KEY_4) /* key_4 */
		MATRIX_KEY(0x02, 0x02, KEY_5) /* key_5 */
		MATRIX_KEY(0x02, 0x03, KEY_6) /* key_6 */
		MATRIX_KEY(0x02, 0x04, KEY_VOLUMEUP) /* key_vol_up */
		MATRIX_KEY(0x03, 0x00, KEY_C) /* key_call_log */
		MATRIX_KEY(0x03, 0x01, KEY_7) /* key_7 */
		MATRIX_KEY(0x03, 0x02, KEY_8) /* key_8 */
		MATRIX_KEY(0x03, 0x03, KEY_9) /* key_9 */
		MATRIX_KEY(0x03, 0x04, KEY_VOLUMEDOWN) /* key_vol_down */
		MATRIX_KEY(0x04, 0x00, KEY_H) /* key_headset */
		MATRIX_KEY(0x04, 0x01, KEY_KPASTERISK) /* key_* */
		MATRIX_KEY(0x04, 0x02, KEY_0) /* key_0 */
		MATRIX_KEY(0x04, 0x03, KEY_GRAVE) /* key_# */
		MATRIX_KEY(0x04, 0x04, KEY_MUTE) /* key_mute */
		>;

		/* Optional board specific properties */
		col-debounce-filter-period = <5>;
		row-output-enabled;
		pull-up-enabled;

	};
};