Hi Scott,

On Sat, Feb 14, 2015 at 08:49:15AM -0800, Scott Branden wrote:

Hi Dmitry,

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

I looked and I could not locate it written down either. I think Grant is
in Santa Rosa this week, I'll ask him to clarify.

On 15-02-09 04:51 PM, Dmitry Torokhov wrote:

quoted

Hi Scott,

On Mon, Feb 09, 2015 at 04:07:40PM -0800, Scott Branden wrote:

quoted

Documents the Broadcom keypad controller device tree bindings.

Reviewed-by: Ray Jui <rjui@broadcom.com>
Signed-off-by: Scott Branden <sbranden@broadcom.com>
---
 .../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?

What I meant that interrupt binding allows specifying the trigger and
you have separate binding for trigger here. It would be nice to have
just one (the standard interrupt binding).

quoted

quoted

+
+- 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

quoted

+	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.

As I mentioned I'll try to get clarification on this.

Clash changes should not happen because as new standard properties
are added the drivers should be adjusted to use the new dt-bindings?

This is a misconception: device tree bindings are supposed to form ABI
(and the goal to eventually separate them from the kernel) and so we
need to support old bindings in new kernels.

Thanks.

-- 
Dmitry