ARM: dts: sunxi: A20-OlinuXino-Lime2 raise dcdc2 lower voltage limit

ARM: dts: sunxi: A20-OlinuXino-Lime2 raise dcdc2 lower voltage limit

[Iain Paton]

The Lime2 is not stable if the cpu core voltage is reduced below 1v. To
prevent any problems when operating points are enabled, raise the pmic dcdc2
lower voltage limit to 1v.

Signed-off-by: Iain Paton <ipaton0@gmail.com>
---

Maxime, I realise the axp209 nodes will probably end up abstracted somewhat 
differently once all of the patches Chen-Yu posted are reviewed and picked
up and I can redo the lime2 dts to fit once that's done.
For now, the lime2 dts defines the full axp209 node itself including all of
the regulators, so if the lowest opp with the 0.9v setting is enabled this 
will cause problems.

Up to you if you want to take this patch now or we wait until the axp209.dtsi
lands and refactor the lime2 dts appropriately then.

 arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
index ed364d5..910318a 100644
--- a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
+++ b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
@@ -159,7 +159,7 @@
 					};
 
 					vdd_cpu: dcdc2 {
-						regulator-min-microvolt = <700000>;
+						regulator-min-microvolt = <1000000>;
 						regulator-max-microvolt = <2275000>;
 						regulator-always-on;
 					};
-- 
2.1.3

ARM: dts: sunxi: A20-OlinuXino-Lime2 raise dcdc2 lower voltage limit

[wens Tsai]

On Thu, Jan 8, 2015 at 6:21 AM, Iain Paton <ipaton0@gmail.com> wrote:
> The Lime2 is not stable if the cpu core voltage is reduced below 1v. To
> prevent any problems when operating points are enabled, raise the pmic dcdc2
> lower voltage limit to 1v.
>
> Signed-off-by: Iain Paton <ipaton0@gmail.com>
> ---
>
> Maxime, I realise the axp209 nodes will probably end up abstracted somewhat
> differently once all of the patches Chen-Yu posted are reviewed and picked
> up and I can redo the lime2 dts to fit once that's done.
> For now, the lime2 dts defines the full axp209 node itself including all of
> the regulators, so if the lowest opp with the 0.9v setting is enabled this
> will cause problems.
>
> Up to you if you want to take this patch now or we wait until the axp209.dtsi
> lands and refactor the lime2 dts appropriately then.
>
>  arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> index ed364d5..910318a 100644
> --- a/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> +++ b/arch/arm/boot/dts/sun7i-a20-olinuxino-lime2.dts
> @@ -159,7 +159,7 @@
>                                         };
>
>                                         vdd_cpu: dcdc2 {
> -                                               regulator-min-microvolt = <700000>;
> +                                               regulator-min-microvolt = <1000000>;
>                                                 regulator-max-microvolt = <2275000>;

You should lower the maximum voltage as well, either in this patch
or when you redo all the regulators. AFAIK the SoC certainly cannot
take up to 2.275V. The regulator nodes are supposed to say what
the board can handle.

ChenYu

>                                                 regulator-always-on;
>                                         };
> --
> 2.1.3
>

[linux-sunxi] Re: ARM: dts: sunxi: A20-OlinuXino-Lime2 raise dcdc2 lower voltage limit

[Iain Paton]

On 08/01/15 03:54, wens Tsai wrote:

> You should lower the maximum voltage as well, either in this patch
> or when you redo all the regulators. AFAIK the SoC certainly cannot
> take up to 2.275V. The regulator nodes are supposed to say what
> the board can handle.

Yes, I suspect several of them are not currently sensible. I just used 
the limits from the pmic datasheet at the time as there were no other 
boards with axp209 regulator defined, no fex file for the lime2 etc.

I likely would have sent a full respin based on your patches, but as 
only bits have been applied it seemed better to do this minimal one 
and fix the rest properly later. 
I can do a couple of the other Olimex boards that I have available 
to test while I'm doing it.

Iain

[linux-sunxi] Re: ARM: dts: sunxi: A20-OlinuXino-Lime2 raise dcdc2 lower voltage limit

[Maxime Ripard]

On Thu, Jan 08, 2015 at 05:17:06PM +0000, Iain Paton wrote:
> On 08/01/15 03:54, wens Tsai wrote:
> 
> > You should lower the maximum voltage as well, either in this patch
> > or when you redo all the regulators. AFAIK the SoC certainly cannot
> > take up to 2.275V. The regulator nodes are supposed to say what
> > the board can handle.
> 
> Yes, I suspect several of them are not currently sensible. I just used 
> the limits from the pmic datasheet at the time as there were no other 
> boards with axp209 regulator defined, no fex file for the lime2 etc.
> 
> I likely would have sent a full respin based on your patches, but as 
> only bits have been applied it seemed better to do this minimal one 
> and fix the rest properly later. 
> I can do a couple of the other Olimex boards that I have available 
> to test while I'm doing it.

All the meaningful patches should have been merged by now, so it would
be good if you could resend this with the proper limits for all the
regulators enabled.

Thanks!
Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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