On Thu, Jun 5, 2025 at 1:54 PM Krzysztof Kozlowski [off-list ref] wrote:

On 05/06/2025 07:48, Pengyu Luo wrote:

quoted

Document stylus support. Optional support for DT properties:
  - `goodix,stylus-enable`
  - `goodix,stylus-pressure-level`
  - `goodix,physical-x`
  - `goodix,physical-y`

Signed-off-by: Pengyu Luo <mitltlatltl@gmail.com>
---
 .../input/touchscreen/goodix,gt9916.yaml      | 23 +++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix,gt9916.yaml b/Documentation/devicetree/bindings/input/touchscreen/goodix,gt9916.yaml
index c40d92b7f..e5476ea36 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/goodix,gt9916.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/goodix,gt9916.yaml

@@ -44,6 +44,27 @@ properties:
   touchscreen-size-y: true
   touchscreen-swapped-x-y: true

+  goodix,stylus-enable:
+    type: boolean
+    description:
+      Indicates that stylus (pen) functionality is enabled. If present,

Looks like deducible from the compatible.

quoted

+      the driver will initialize stylus-specific input reporting.

What if my driver does something else? Shall we change the binding? No.

Ack, I will drop it in v2.

quoted

+
+  goodix,physical-x:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Physical width of the touchscreen in millimeters.

No, use existing input properties.

Ack, I overlooked it.

quoted

+
+  goodix,physical-y:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Physical height of the touchscreen in millimeters.
+
+  goodix,stylus-pressure-level:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Number of discrete pressure levels supported by the stylus.
+      The reported ABS_PRESSURE range will be 0 to
+      (goodix,stylus-pressure-level - 1).

Use existing input properties.

With a quick check, I think there is no suitable property for stylus,
"touchscreen-max-pressure" is for touchscreen, not for stylus. AFAIK,
Pressure data is reported by stylus, received by touch IC.

Best wishes,
Pengyu