[PATCH V3 12/14] ARM: dts: stm32: Repair PMIC configuration on AV96

[Pascal PAILLET-LME]

> -----Original Message-----
> From: Marek Vasut <marex at denx.de>
> Sent: jeudi 2 avril 2020 15:07
> To: Pascal PAILLET-LME <p.paillet at st.com>; Patrick DELAUNAY
> <patrick.delaunay at st.com>; Patrice CHOTARD <patrice.chotard at st.com>; u-
> boot at lists.denx.de
> Cc: Manivannan Sadhasivam <manivannan.sadhasivam at linaro.org>;
> Alexandre TORGUE <alexandre.torgue at st.com>
> Subject: Re: [PATCH V3 12/14] ARM: dts: stm32: Repair PMIC configuration
> on AV96
> 
> On 4/2/20 2:53 PM, Pascal PAILLET-LME wrote:
> > Hi Marek,
> 
> Hi,
> [...]
> >>>>>>>  			vdd: buck3 {
> >>>>>>>  				regulator-name = "vdd";
> >>>>>>> -				regulator-min-microvolt = <3300000>;
> >>>>>>> -				regulator-max-microvolt = <3300000>;
> >>>>>>> +				regulator-min-microvolt = <2900000>;
> >>>>>>> +				regulator-max-microvolt = <2900000>;
> >>>>>>>  				regulator-always-on;
> >>>>>>>  				st,mask_reset;
> >>>>>>>  				regulator-initial-mode = <0>; @@ -
> >> 268,6 +279,7 @@
> >>>>>>>  				regulator-name = "vbus_otg";
> >>>>>>>  				interrupts = <IT_OCP_OTG 0>;
> >>>>>>>  				interrupt-parent = <&pmic>;
> >>>>>>> +				regulator-active-discharge = <1>;
> >>>>>> It seems this setting introduced other-consumption, it should not be
> >> used.
> >>>>> Other-consumption ? What does that mean ?
> >>>>
> >>>> It's a typo, Patrick means over-consumption.
> >>>
> >>> Ah. Do you have any details on that ?
> >>
> >> Sorry for typo.
> >>
> >> No details on my side, it was a Pascal Paillet's direct feedback (Maintainer
> of
> >> STPMIC1 driver in Linux).
> > You can enable the active discharge on the STPMIC1's VBUSOTG. But, as
> soon as a USB host peripheral (such as laptop) will attach and provide VBUS,
> there will be a ~8mA continuous power consumption on VBUS through this
> OTG active discharge. There is no functional issue behind this 8mA; but you
> need to know that 8mA is not compliant with the USB suspend constraint
> (2.5mA max).
> 
> So why is it in there ?
Sorry, I'm not sure to catch your point... The property is available because the stpmic1
Propose this feature (enable a pull down resistor when VBUS_OTG is disabled). We have
Found during some test that it is better to not enable active discharge on vbus_otg.
I hope it answers,
pascal