Re: [PATCH v6 2/3] dt-bindings: input: Add TouchNetix axiom touchscreen

[Kamel Bouhara <kamel.bouhara@bootlin.com>]

Hello,

On Wed, Jan 31, 2024 at 08:28:43AM +0100, Krzysztof Kozlowski wrote:
> On 30/01/2024 23:28, Rob Herring wrote:
> > On Fri, Jan 26, 2024 at 12:46:16PM +0100, Krzysztof Kozlowski wrote:
> >> On 25/01/2024 17:58, Kamel Bouhara wrote:
> >>> +  reset-gpios:
> >>> +    maxItems: 1
> >>> +
> >>> +  vdda-supply:
> >>> +    description: Analog power supply regulator on VDDA pin
> >>> +
> >>> +  vddi-supply:
> >>> +    description: I/O power supply regulator on VDDI pin
> >>> +
> >>> +  startup-time-ms:
> >>> +    description: delay after power supply regulator is applied in ms
> >>
> >> That's a regulator property - ramp up time.
> >
> > I'm sure there's an existing property name that could be used.
> >
> > But why is it needed? Is it variable per board with the same device? If
> > not, it should be implied by the compatible.
>
> I meant, that regulators have such property. Unless this is coming from
> the device needs, not from the regulator?
>

After looking again into the device's datasheet [1], the delay (startup
time) is not really optional and it shouldn't be set through devicetree.

IIUC, it have to be set unconditionally after a device reset or
a vdda assertion.

[1]: https://www.touchnetix.com/media/dgnjohor/tnxd00394-a3-axiom_ax54a_2d_touch_controller_datasheet.pdf
--
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com