Date: Sat, 23 Nov 2024 22:31:50 +0100
From: Andreas Kemnade <andreas@kemnade.info>
To: Mithil Bavishi <bavishimithil@gmail.com>
Cc: Laurent.pinchart@ideasonboard.com, aaro.koskinen@iki.fi,
 airlied@gmail.com, conor+dt@kernel.org, devicetree@vger.kernel.org,
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 rogerq@kernel.org, simona@ffwll.ch, thierry.reding@gmail.com,
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Subject: Re: [PATCH v3 10/10] ARM: dts: ti: omap: samsung-espresso10: Add
 initial support for Galaxy Tab 2 10.1
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Am Sat, 23 Nov 2024 19:26:33 +0000
schrieb Mithil Bavishi <bavishimithil@gmail.com>:

> > well, look at the schematics and see how it is wired ;-)  
> 
> Schematic mentions vddtx, vdda, vdd and vbus, so unsure about that.
> VDDTX is the one with 2.8V, VDD and VBUS are at 1.8V and VDDA is grounded,
> it just gets the input from GDNA from the same touch sensor.
> 
> > As the vendor kernel seem to
> > set i2c to gpio mode, so probably because the vio-supply is powered
> > down according to the board file you posted.
> > So it might be vio-supply only or vio and vdd-supply combined.
> > In any case document what you have seen in the vendor kernel.  
> 
> https://github.com/Unlegacy-Android/android_kernel_ti_omap4/blob/3.4/common/arch/arm/mach-omap2/board-espresso-input.c
> This just makes it more confusing. Very confused on what is what now xD.
> reg_touch_ldo_en is 2.8V which goes to VDDTX, it is gpmc_nwp.gpio_54 - TSP_LDO_ON
> ldo6 is 1.8V presumably ldo6 (VAP_IO_1.8V) which goes to VDD, VBUS.
> 
well, I think I2C bus runs at 1.8V, and there is IO_1.8V in the name,
so vio-supply should be something at 1.8V, so probably ldo6 is
vio-supply. Maybe add a remark in the comments. But then it might be
not a good idea to turn that off in suspend. if the other regulator is
kept on.

> > basically says that standard touchscreen properties are accepted below
> > rmi4-f11.   
> 
> But we do not use any of those properties. If you're talking about the
> touchscreen-size-x/y, even in the examples those are out of rmi4-f11, in
> the parent node.
>
Where do you see those examples? Here touchscreen-invert-y is below
rmi4-f11.
https://elixir.bootlin.com/linux/v6.12/source/Documentation/devicetree/bindings/input/syna,rmi4.yaml#L269

We have also the warning from dtbs_check:
arch/arm/boot/dts/ti/omap/omap4-samsung-espresso10.dtb:
synaptics-rmi4-i2c@20: Unevaluated properties are not allowed
('avdd-supply', 'touchscreen-size-x', 'touchscreen-size-y' were
unexpected)

Regards,
Andreas