Re: [PATCH v3 4/6] dt-bindings: touchscreen: fsl,imx6ul-tsc: support glitch thresold

Conor Dooley
2025-09-16T19:25:59Z

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On Tue, Sep 16, 2025 at 11:55:17AM -0400, Frank Li wrote:
> On Mon, Sep 15, 2025 at 09:53:06PM +0200, Dario Binacchi wrote:
> > 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>
> >
> > ---
> >
> > Changes in v3:
> > - Remove the final part of the description that refers to
> > implementation details.
> >
> > .../bindings/input/touchscreen/fsl,imx6ul-tsc.yaml | 12 ++++++++++++
> > 1 file changed, 12 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..6214d8be5a99 100644
> > --- a/Documentation/devicetree/bindings/input/touchscreen/fsl,imx6ul-tsc.yaml
> > +++ b/Documentation/devicetree/bindings/input/touchscreen/fsl,imx6ul-tsc.yaml
> > @@ -62,6 +62,18 @@ 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 have to use ns here. You can caculate in driver to match to closed one.

That is what he is saying it is doing - "internally the value is
converted to IPG clock cycles" and so on. Your repeated misunderstanding
of this though points out that maybe the description is still lacking?

Dario, how about:
| The gitch threshold in nanoseconds. Drivers must convert this value to
| IPG clock cycles and map it to one of the 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
?
I dropped the bit about arbitrary values, due to my comment on the other
version a few mins ago.

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