Re: [PATCH 1/2] Input: bcm-keypad: add device tree bindings

[Dmitry Torokhov <dmitry.torokhov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

Hi Scott,

On Mon, Feb 09, 2015 at 04:07:40PM -0800, Scott Branden wrote:
> Documents the Broadcom keypad controller device tree bindings.
> 
> Reviewed-by: Ray Jui <rjui-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> Signed-off-by: Scott Branden <sbranden-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> ---
>  .../devicetree/bindings/input/brcm,bcm-keypad.txt  | 118 +++++++++++++++++++++
>  1 file changed, 118 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/input/brcm,bcm-keypad.txt
> 
> diff --git a/Documentation/devicetree/bindings/input/brcm,bcm-keypad.txt b/Documentation/devicetree/bindings/input/brcm,bcm-keypad.txt
> new file mode 100644
> index 0000000..645829d
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/input/brcm,bcm-keypad.txt
> @@ -0,0 +1,118 @@
> +* 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.
> +
> +- key-interrupt-trigger-type: The type of interrupt trigger asociated with the Keypad matrix.
> +
> +	KEYPAD_INTERRUPT_NO_TRIGGER	=	0
> +	KEYPAD_INTERRUPT_RISING_EDGE	=	1
> +	KEYPAD_INTERRUPT_FALLING_EDGE	=	2
> +	KEYPAD_INTERRUPT_BOTH_EDGES	=	3

Can we get this data from the interrupt spec?

> +
> +- 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

I could swear device-specific properties should be in form of
<vendor-prefix>,<property-name> to ensure it won't clash with changes on
subsystem level later on. Device-tree folks, what say you?

> +
> +- 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.
> +
> +- Keys represented as child nodes: Each key connected to the keypad
> +  controller is represented as a child node to the keypad controller
> +  device node and should include the following properties.
> +  - row: the row number to which the key is connected.
> +  - column: the column number to which the key is connected.
> +  - code: the key-code to be reported when the key is pressed
> +    and released.

That does not seem to be right, linux,keymap is a list, not a subtree.
I'd simply refer to
Documentation/devicetree/bindings/input/matrix-keymap.txt for details.

> +
> +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 */
> +		key-interrupt-trigger-type = <3>;
> +		col-debounce-filter-period = <5>;
> +		row-output-enabled;
> +		pull-up-enabled;
> +
> +	};
> +};
> -- 
> 2.2.2
> 

Thanks.

-- 
Dmitry
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