[PATCH] ARM: dts: exynos: Fix invalid maximum voltage for buck9 supplying SD card

[Markus Reichl]

Hi Javier,

Am Freitag, 25. März 2016, 02:45:20 schrieb Javier Martinez Canillas:
> Hello Krzysztof,
> 
> On 03/24/2016 05:12 AM, Krzysztof Kozlowski wrote:
> > The buck9 regulator of S2MPS11 PMIC had incorrect maximum voltage -
> > lower by 5 mV than specified by datasheet. This buck9 provides power to
> > other regulators, including LDO13 and LDO19 which supply the MMC2 (SD
> > card).
> > 
> > When constraints were applied, the depending regulators were not
> > providing enough power, leading to SD card detection errors:
> > 	mmc1: card never left busy state
> > 	mmc1: error -110 whilst initialising SD card
> > 
> > Fixes: 86a2d2ac5e5d ("ARM: dts: Add dts file for Odroid XU3 board")
> > Signed-off-by: Krzysztof Kozlowski <k.kozlowski at samsung.com>
> > 
> > ---
> > 
> > The issue can be reproduced on next-20160324 with
> > bae4fdc88d7f7dda1 (regulator: core: Ensure we are at least in bounds for our constraints).
> > ---
> >  arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> > index 1bd507bfa750..82b2ba632cf6 100644
> > --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> > +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
> > @@ -299,7 +299,7 @@
> >  			buck9_reg: BUCK9 {
> >  				regulator-name = "vdd_2.8v_ldo";
> >  				regulator-min-microvolt = <3000000>;
> > -				regulator-max-microvolt = <3750000>;
> > +				regulator-max-microvolt = <3755000>;
> >  				regulator-always-on;
> >  				regulator-boot-on;
> >  			};
> > 
> 
> I tested next-20160324 + $SUBJECT on an Odroid XU4 (with exynos_defconfig)
> and while it's true that the patch makes the SD card error to go away, I see
> that the s2mps11 regulator driver fails to probe due an -EINVAL being return
> by machine_constraints_voltage() -> _regulator_do_set_voltage():
> 
> [    1.710300] vdd_2.8v_ldo: failed to apply 3755000-3755000uV constraint(-22)
> [    1.716387] s2mps11-pmic s2mps11-regulator: regulator init failed for 46
> [    1.734878] s2mps11-pmic: probe of s2mps11-regulator failed with error -22
> 
> I wonder how neither Markus nor you saw this issue when testing so maybe I'm
> doing something wrong? Since AFAICT it's only working because the driver fails
> to probe so the same effect can be achieved disabling CONFIG_REGULATOR_S2MPS11.
> 
> Best regards,
> 
My first test yesterday was with next-20160324 + $SUBJECT, too, and I encountered the same
error of the regulator system as you.
As with next-20160324 I could not get the ethernet chip running (with or without $SUBJECT) I switched back to
next-20160323 + $SUBJECT and posted the result above.

Regards,
--
Markus