Re: [PATCH v2 4/6] dt-bindings: touchscreen: fsl,imx6ul-tsc: support glitch thresold

On Mon, Sep 15, 2025 at 10:30:26AM -0400, Frank Li wrote:

On Sun, Sep 14, 2025 at 07:16:01PM +0200, Dario Binacchi wrote:

quoted

Support the touchscreen-glitch-threshold-ns property. Unlike the
generic description in touchscreen.yaml, this controller maps the
provided value to one of four discrete thresholds internally.

Signed-off-by: Dario Binacchi <dario.binacchi@amarulasolutions.com>
---

(no changes since v1)

 .../input/touchscreen/fsl,imx6ul-tsc.yaml         | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/touchscreen/fsl,imx6ul-tsc.yaml b/Documentation/devicetree/bindings/input/touchscreen/fsl,imx6ul-tsc.yaml
index 678756ad0f92..310af56a0be6 100644
--- a/Documentation/devicetree/bindings/input/touchscreen/fsl,imx6ul-tsc.yaml
+++ b/Documentation/devicetree/bindings/input/touchscreen/fsl,imx6ul-tsc.yaml

@@ -62,6 +62,21 @@ properties:
     description: Number of data samples which are averaged for each read.
     enum: [ 1, 4, 8, 16, 32 ]

+  touchscreen-glitch-threshold-ns:
+    description: |
+      Unlike the generic property defined in touchscreen.yaml, this
+      controller does not allow arbitrary values. Internally the value is
+      converted to IPG clock cycles and mapped to one of four discrete
+      thresholds exposed by the TSC_DEBUG_MODE2 register:
+
+        0: 8191 IPG cycles
+        1: 4095 IPG cycles
+        2: 2047 IPG cycles
+        3: 1023 IPG cycles

you should use ns
   enum:
      - 1023
      - 2047
      - 4095
      - 8191

you can limit only 4 values, but unit have to ns. your driver map it to
register value.

Looking at the driver change, I think Dario is already doing that. The
text here is just talking about how the controller doesn't support
anything other than these 4 glitch threshold and mapping must be done in
some way.

quoted

+
+      Any value provided in device tree is converted to cycles and rounded
+      up to the next supported threshold, or to 8191 if above 4095.

This seems to be the implementation details of one particular driver,
and does not belong in a binding.

quoted

+
 required:
   - compatible
   - reg
--
2.43.0