Re: [PATCH v2 3/3] riscv: dts: spacemit: Enable USB3.0 on BananaPi-F3

[Yixun Lan <dlan@gentoo.org>]

Hi Ze,

I've done a quick check of the "regulator-always-on" issue, 
it's ok to drop the one from hub, but not the vbus one..

On 09:21 Thu 08 Jan     , Yixun Lan wrote:
> Hi Ze,
> 
>   thanks for your patch, I have few comments, see below..
> 
> On 20:05 Wed 07 Jan     , Ze Huang wrote:
> > Enable the DWC3 USB 3.0 controller and its associated usbphy2 on the
> > Banana Pi F3 board.
> > 
> > The board utilizes a VLI VL817 hub, which requires two separate power
> > supplies: one VBUS and one for hub itself. Add two GPIO-controlled
> > fixed-regulators to manage this.
> > 
> > Tested-by: Aurelien Jarno <aurelien@aurel32.net>
> > Signed-off-by: Ze Huang <huang.ze@linux.dev>
> > ---
> >  arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts | 48 +++++++++++++++++++++++++
> >  1 file changed, 48 insertions(+)
> > 
> > diff --git a/arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts b/arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts
> > index 3f10efd925dc..013df91c6a4c 100644
> > --- a/arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts
> > +++ b/arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts
> > @@ -59,6 +59,26 @@ reg_vcc_4v: vcc-4v {
> >  		regulator-always-on;
> >  		vin-supply = <&reg_dc_in>;
> >  	};
> > +
> > +	usb3_vbus: regulator-vbus-5v {
> I've checked the schematics, the name is 5V_VBUS there, so for the consistency
> with previous naming convention, let's change to:
> 	usb3_vbus_5v: usb3-vbus-5v 
> 
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "USB30_VBUS";
> > +		regulator-min-microvolt = <5000000>;
> > +		regulator-max-microvolt = <5000000>;
> ..
> > +		regulator-always-on;
> do you think the "always-on" property really necessary? it indicate the
> power regulator is critical, and should never been disabled even during
> suspend/resume state, for the case of USB, I think it should be totally
> fine to poweroff once the device is not used(suspended) or even disabled
> 
> besides, the regulator is designed with a gpio enabling/disabling control
> which means it can be powered to on/off state?
> 
not ok to drop, see comment below at &usb_dwc3 

> > +		gpio = <&gpio K1_GPIO(97) GPIO_ACTIVE_HIGH>;
> > +		enable-active-high;
> > +	};
> > +
> > +	usb3_vhub: regulator-vhub-5v {
> why use vhub, but not hub? where does this name come from?
> 
> and for same reason, the name in schematics is VCC5V0_HUB, so how about
> change it to:
> 	usb3_hub_5v: usb3-hub-5v 
> 
> > +		compatible = "regulator-fixed";
> > +		regulator-name = "USB30_VHUB";
>                                     ~~~need to fix too, if above is valid
> > +		regulator-min-microvolt = <5000000>;
> > +		regulator-max-microvolt = <5000000>;
> ..
> > +		regulator-always-on;
> ditto
ok to drop, as it's already handled at drivers/usb/misc/onboard_usb_dev.c
which will explicitly request the regulator and enable it

> > +		gpio = <&gpio K1_GPIO(123) GPIO_ACTIVE_HIGH>;
> > +		enable-active-high;
> > +	};
> >  };
> >  
> >  &combo_phy {
> > @@ -67,6 +87,34 @@ &combo_phy {
> >  	status = "okay";
> >  };
> >  
> ..
> > +&usbphy2 {
> > +	status = "okay";
> > +};
> > +
> > +&usb_dwc3 {
> > +	dr_mode = "host";
> > +	vbus-supply = <&usb3_vbus>;
due to drivers/usb/dwc3/dwc3-generic-plat.c has no handler to request regulator
there will be problem if "regulator-always-on" property is removed..

> > +	#address-cells = <1>;
> > +	#size-cells = <0>;
> > +	status = "okay";
> > +

-- 
Yixun Lan (dlan)