Re: [PATCH 2/2] ARM: DTS: Add devicetree file for the Galaxy S2

[Marek Szyprowski]

Hi Paul,

On 2020-03-31 15:09, Paul Cercueil wrote:
> Cc: PaweÅ Chmiel <pawel.mikolaj.chmiel@xxxxxxxxx>
>
> Hi Marek,
>
> Le mar. 31 mars 2020 Ã 7:36, Marek Szyprowski 
> <m.szyprowski@xxxxxxxxxxx> a Ãcrit :
>> Hi Paul,
>>
>> On 2020-03-18 15:25, Paul Cercueil wrote:
>>>>> Â +ÂÂÂ };
>>>>> Â +
>>>>> Â +ÂÂÂ tsp_reg: regulator-1 {
>>>>> Â +ÂÂÂÂÂÂÂ compatible = "regulator-fixed";
>>>>> Â +ÂÂÂÂÂÂÂ regulator-name = "TSP_FIXED_VOLTAGES";
>>>>> Â +ÂÂÂÂÂÂÂ regulator-min-microvolt = <3300000>;
>>>>> Â +ÂÂÂÂÂÂÂ regulator-max-microvolt = <3300000>;
>>>>> Â +ÂÂÂÂÂÂÂ gpio = <&gpl0 3 GPIO_ACTIVE_HIGH>;
>>>>> Â +ÂÂÂÂÂÂÂ startup-delay-us = <70000>;
>>>>> Â +ÂÂÂÂÂÂÂ enable-active-high;
>>>>> Â +ÂÂÂÂÂÂÂ regulator-boot-on;
>>>>> Â +ÂÂÂÂÂÂÂ regulator-always-on;
>>>>
>>>> Âalways-on and boot-on should not be needed. You have a consumer 
>>>> for this
>>>> Âregulator.
>>>
>>> ÂAbout this: the touchscreen driver does not use a regulator, so I
>>> Âbelieve that's why these properties were here.
>>>
>>> ÂI sent patches upstream to address the issue:
>>> Âhttps://protect2.fireeye.com/url?k=e8aedc29-b53072b3-e8af5766-0cc47a336fae-759579fd576d8382&u=https://lkml.org/lkml/2020/3/15/94 
>>>
>>>
>>> ÂI believe this means I cannot merge the i9100 devicetree until it is
>>> Âacked.
>>
>> One more information - similar change has been already posted, but it
>> looks it got lost then: https://patchwork.kernel.org/patch/10550903/
>
> I was aware of this patch, but didn't know it was sent upstream.
>
> This other patch uses two regulators, vdd/avdd but doesn't give any 
> reason why.
>
I've checked the UniversalC210 schematic, which uses the same 
touchscreen chip. There are 2 supplies to the touchscreen chip: 2.8V VDD 
and 3.3V AVDD. Both are enabled by the same GPIO pin though. There is 
however no reset GPIO pin there.

> PaweÅ, is that really needed?
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland