[PATCH] arm: dts: sun50i-h6-orangepi-3: disable aldo2 regulator

[Andre Przywara]

On Tue,  7 Sep 2021 19:23:26 +0300
Maxim Karasev <begs at disroot.org> wrote:

Hi Maxim,

please add the respective maintainers in To: or CC:, as reported by
scripts/get_maintainer.pl.
Also please add at least "sunxi" or "allwinner" somewhere in the subject
line, that helps the reduce the response time ;-)

> Mainline TF-A has a broken behavior - it enables all used AXP regulator
> outputs, without much reason.

Without that code you could not use most peripherals powered by the PMIC
in U-Boot, the PHY being the most prominent one.
But yes, it's a long standing issue - at least for the OPi3, which seems
to be one of the few boards really having an issue with that.
And the real solution is to drop the regulator handling in TF-A, and use a
DM compliant AXP driver in U-Boot. Samuel's recent work should have
brought that a bit closer, but it's still quite some work ahead:
https://oftc.irclog.whitequark.org/linux-sunxi/2021-10-11#30291278;

> It breaks PHY on Orange Pi 3 and other boards, because they a specific
> power-on sequence is required. aldo2 which is enabled by TF-A is just a
> half of PHY's power and the other half that is untouched by TF-A must be
> enabled simultaneously (even a small difference may cause a break-down).

I wish OrangePi would have designed a bit less of a special snowflake
here.

> If not TF-A, kernel driver would do everything correctly.
> 
> However, some boards rely on this behavior, so it's impossible to get
> rid of it.
> 
> TF-A recently started checking regulator status, and now it enables a
> regulator only if it's status is "okay". Disabling regulator in U-Boot's
> dts workarounds the problem.

The problem is that there is no such thing as "U-Boot's dts". I always use
that DT to pass it on to the kernel (via $fdtcontroladdr), and this is the
designated way to use UEFI. And that is just one reason we don't accept DT
hacks just in U-Boot.

I was thinking about adding a TF-A build option that would skip regulator
setup altogether, which would then become standard in some happy feature
when U-Boot takes proper care of regulators.
Maybe you can just disable this already in your TF-A build, to see if that
fixes your issues?

In any case your patch below is unfortunately not a solution.

Cheers,
Andre

> ---
>  arch/arm/dts/sun50i-h6-orangepi-3.dts | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/arm/dts/sun50i-h6-orangepi-3.dts b/arch/arm/dts/sun50i-h6-orangepi-3.dts
> index 7e83f6146f..9f91e4ec88 100644
> --- a/arch/arm/dts/sun50i-h6-orangepi-3.dts
> +++ b/arch/arm/dts/sun50i-h6-orangepi-3.dts
> @@ -207,6 +207,10 @@
>  				regulator-min-microvolt = <3300000>;
>  				regulator-max-microvolt = <3300000>;
>  				regulator-name = "vcc33-audio-tv-ephy-mac";
> +				/* This regulator must be enabled by the kernel,
> +				 * not by u-boot or TF-A, otherwise power-on
> +				 * sequence will be wrong and PHY won't work */
> +				status = "disabled";
>  			};
>  
>  			/* ALDO3 is shorted to CLDO1 */