[PATCH 4/8] ARM: dts: sun8i: Add touchscreen node for sun8i-a23-gt90h

[Icenowy Zheng]

23.08.2016, 03:08, "Hans de Goede" <hdegoede at redhat.com>:
> Hi,
>
> On 22-08-16 20:30, Maxime Ripard wrote:
>>  On Mon, Aug 08, 2016 at 09:43:14PM +0200, Hans de Goede wrote:
>>>  The gt90h tablet has a gsl3675 touchscreen, add a dt node describing it.
>>>
>>>  Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>>>  ---
>>>   arch/arm/boot/dts/sun8i-a23-gt90h-v4.dts | 8 ++++++++
>>>   1 file changed, 8 insertions(+)
>>>
>>>  diff --git a/arch/arm/boot/dts/sun8i-a23-gt90h-v4.dts b/arch/arm/boot/dts/sun8i-a23-gt90h-v4.dts
>>>  index f27ebbb..da55b5a 100644
>>>  --- a/arch/arm/boot/dts/sun8i-a23-gt90h-v4.dts
>>>  +++ b/arch/arm/boot/dts/sun8i-a23-gt90h-v4.dts
>>>  @@ -53,6 +53,14 @@
>>>           status = "okay";
>>>   };
>>>
>>>  +&gsl1680 {
>>>  + compatible = "silead,gsl3675";
>>>  + touchscreen-fw-name = "silead/gsl3675-gt90h.fw";
>>
>>  That's not documented anywhere, and looks really suspicious.
>
> Ugh, that should have been in:
>
> Documentation/devicetree/bindings/input/touchscreen/silead_gsl1680.txt
>
> But somehow it is not (I believe it was there in earlier revisions of
> the patch), I'll send a patch to fix this.
>
> About it being suspicious, this is not really firmware it is a bunch
> of configuration data / lookup tables for the controller which tell
> it in which order the touchscreen horizontal / vertical sensor
> lines are connected to its sense pins, and what values to send
> for finger x% between line z and line z+1, which differs per
> tablet model, since not all tablets use the same digitizer.

I do think it's a mixture of executable MCU codes and data.
The GSL1680 datasheet indicates that there's a 32-bit MCU in it.

>
> Regards,
>
> Hans
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel