On Tue, Nov 27, 2018 at 10:38:52AM +0100, Maxime Ripard wrote:
> On Mon, Nov 26, 2018 at 05:27:50PM +0200, Priit Laes wrote:
> > From: Olliver Schinagl <oliver@xxxxxxxxxxx>
> >
> > With commit b43776d65a33b46092 ("ARM: dts: sunxi: Use axp209.dtsi for
> > Olinuxino Lime2") we force them an arbitrary 2.8 volts. Granted, for
> > LDO3 this may be less arbitrary, but for LDO4 this is just wrong.
> >
> > In the defense of LDO3, LDO3 is the regulator that feeds port bank E,
> > which has no other purpose then a CSI/TS interface, however the case
> > may still be, that the connected IO may be just as well be 3.3 volts.
> > The big misnomer is however, that the schematic names GPIO-2 pin4
> > LDO3_2.8V, rather then VDD-CSI0 or similar.
> >
> > This is much worse for LDO4 however, which is not referenced on any
> > pin, is now set to 2.8 volts, but port bank G can also support various
> > other peripherals such as UARTS etc.
> >
> > By having 2.8 volts however for LDO4, we thus now have peripherals that
> > no longer function properly all of the time.
> >
> > Ideally, we want to set a supply voltage for each port bank, but the
> > monolithic nature of the sunxi pinctroller currently prevents this and
> > as such, the board should at least configure the LDO4 with the proper
> > ranges.
> >
> > Until we can set the consumer at the port bank level, a child
> > device-tree has to do something like:
> >
> > ®_ldo4 {
> > regulator-min-microvolt = <3300000>;
> > regulator-max-microvolt = <3300000>;
> > };
> >
> > While doing this the same way results in the same solution currently,
> > we force the hack into the final devicetree rather then having it wrong
> > at the board level.
> >
> > Signed-off-by: Olliver Schinagl <oliver@xxxxxxxxxxx>
> > Signed-off-by: Priit Laes <plaes@xxxxxxxxx>
> > ---
> > arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts | 7 ++++---
> > 1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> > index ffafe97..1b9867f 100644
> > --- a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> > +++ b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> > @@ -250,9 +250,10 @@
> > };
> >
> > ®_ldo4 {
> > - regulator-min-microvolt = <2800000>;
> > - regulator-max-microvolt = <2800000>;
> > - regulator-name = "vddio-csi1";
> > + regulator-always-on;
> > + regulator-min-microvolt = <1250000>;
> > + regulator-max-microvolt = <3300000>;
> > + regulator-name = "vdd-io-pg";
>
> As we discussed on the U-Boot ML already, this shouldn't be made
> always-on but tied to the consumer device (the pinctrl one) instead.
Can you test that patch (not tested):
http://code.bulix.org/h02vha-514284?raw
Thanks!
Maxime
--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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