Re: [PATCH 1/8] dt-bindings: HID: i2c-hid: elan: Introduce Elan eKTH8D18
From: Doug Anderson <dianders@chromium.org>
Date: 2025-03-14 21:58:55
Also in:
chrome-platform, linux-devicetree, linux-input, linux-mediatek, lkml
Hi, On Wed, Mar 12, 2025 at 3:43 AM Chen-Yu Tsai [off-list ref] wrote:
The Elan eKTH8D18 touchscreen controller is an I2C HID device with a longer boot-up time. Power sequence timing wise it is compatible with the eKTH6A12NAY, with a power-on delay of at least 5ms, 20ms out-of-reset for I2C ack response, and 150ms out-of-reset for I2C HID enumeration. Enumeration and subsequent operation follows the I2C HID standard. The eKTH6A12NAY requires longer times for both parts.
Somehow the last sentence above confused me. Can it just be dropped? All you care about is that the new trackpad matches the timings for "eKTH6A12NAY". Not sure what you mean by "eKTH6A12NAY" needing "longer" timings.
quoted hunk ↗ jump to hunk
Add a compatible string for it with the ekth6a12nay one as a fallback. Signed-off-by: Chen-Yu Tsai <wenst@chromium.org> --- .../bindings/input/elan,ekth6915.yaml | 29 ++++++++++++++++--- 1 file changed, 25 insertions(+), 4 deletions(-)diff --git a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml index cb3e1801b0d3..81c391952ccc 100644 --- a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml +++ b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml@@ -4,14 +4,14 @@ $id: http://devicetree.org/schemas/input/elan,ekth6915.yaml# $schema: http://devicetree.org/meta-schemas/core.yaml# -title: Elan eKTH6915 touchscreen controller +title: Elan I2C-HID touchscreen controllers maintainers: - Douglas Anderson <dianders@chromium.org> description: - Supports the Elan eKTH6915 touchscreen controller. - This touchscreen controller uses the i2c-hid protocol with a reset GPIO. + Supports the Elan eKTH6915 and other I2C-HID touchscreen controllers. + These touchscreen controller use the i2c-hid protocol with a reset GPIO. allOf: - $ref: /schemas/input/touchscreen/touchscreen.yaml#@@ -23,12 +23,18 @@ properties: - enum: - elan,ekth5015m - const: elan,ekth6915 + - items: + - enum: + - elan,ekth8d18 + - const: elan,ekth6a12nay
The "enum" above is weird, but it matches what we did for "elan,ekth5015m" so I guess it's fine? I'd leave it up to bindings maintainers. I guess the assumption is that we might add additional touchscreens to the list...
reg: - const: 0x10 + enum: + - 0x10 + - 0x16
Again happy to leave it to the bindings maintainers, but _maybe_ just drop the "reg" parts here and below. It doesn't really have to be part of the bindings.