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

From: [email-masked] (Scott Branden)
Date: Sat, 14 Feb 2015 08:49:15 -0800

Hi Dmitry,

Comments inline.  I still have an issue with vendor prefix as there are 
not documented guidelines I can find in this area?

On 15-02-09 04:51 PM, Dmitry Torokhov wrote:
> 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 <[email-masked]>
>> Signed-off-by: Scott Branden <[email-masked]>
>> ---
>>   .../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?
I don't understand your question. Could you elaborate?
But, looking at this closer this determines when the hardware should 
generate interrupts.  I think we would always need to set it to both 
edges and this binding option can probably we removed?
>
>> +
>> +- 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?
I see examples with and without vendor-prefix.
qcom,pm8xxx-keypad.txt does not have prefixes
st-keyscan.txt does have a prefix

I can't find any documented guidelines for this.
Clash changes should not happen because as new standard properties are 
added the drivers should be adjusted to use the new dt-bindings?
>
>> +
>> +- 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.
Yes, we moved to matrix-keymap and forgot to update this documentation. 
  Will correct - thanks.
>
>> +
>> +Example:
>> +#include "dt-bindings/input/input.h"
>> +
>> +/ {
>> +	keypad: keypad at 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.
>