Re: [PATCH 3/3] ARM: dts: sun8i: r40: bananapi-m2-ultra: Enable usb_otg

[Andre Przywara <andre.przywara@arm.com>]

On Fri, 2 Jul 2021 14:06:01 +0200
Maxime Ripard <maxime@cerno.tech> wrote:

Hi,

> On Fri, Jul 02, 2021 at 10:46:20AM +0800, qianfan wrote:
> > 
> > 在 2021/7/1 22:47, Chen-Yu Tsai 写道:  
> > > On Thu, Jul 1, 2021 at 10:37 PM Andre Przywara <andre.przywara@arm.com> wrote:  
> > > > On Thu,  1 Jul 2021 09:50:09 +0800
> > > > qianfanguijin@163.com wrote:
> > > > 
> > > > Hi,
> > > >   
> > > > > From: qianfan Zhao <qianfanguijin@163.com>
> > > > > 
> > > > > Enable it.
> > > > > 
> > > > > Signed-off-by: qianfan Zhao <qianfanguijin@163.com>
> > > > > ---
> > > > >   arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts | 14 ++++++++++++++
> > > > >   1 file changed, 14 insertions(+)
> > > > > 
> > > > > diff --git a/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts b/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts
> > > > > index a6a1087a0c9b..072535b383b5 100644
> > > > > --- a/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts
> > > > > +++ b/arch/arm/boot/dts/sun8i-r40-bananapi-m2-ultra.dts
> > > > > @@ -43,6 +43,7 @@
> > > > > 
> > > > >   /dts-v1/;
> > > > >   #include "sun8i-r40.dtsi"
> > > > > +#include "sunxi-common-regulators.dtsi"
> > > > > 
> > > > >   #include <dt-bindings/gpio/gpio.h>
> > > > > 
> > > > > @@ -299,6 +300,11 @@
> > > > >        regulator-name = "vdd1v2-sata";
> > > > >   };
> > > > > 
> > > > > +&reg_usb0_vbus {
> > > > > +     gpio = <&pio 8 13 GPIO_ACTIVE_HIGH>; /* PI13 */
> > > > > +     status = "okay";
> > > > > +};  
> > > > So there is the same USB0-DRVVBUS signal connected to this GPIO, but
> > > > also to the AXP's N_VBUSEN line.
> > > > 
> > > > Not sure if that means either of them can control the voltage?  
> > > It's better to use N_VBUSEN if that is connected. Since the PMIC
> > > may have that pin already enabled, it can cause issues with VBUS
> > > input not being correctly used.  
> >
> > I had checked some boards in linux such as sun7i-a20-olinuxino-lime2.dts,
> > they has the same design
> > 
> > that enable VBUS by using a gpio and then connect this gpio to PMIC.
> > 
> > there is a example:
> > 
> > ./sun7i-a20-olinuxino-lime2.dts:&reg_usb0_vbus {
> > ./sun7i-a20-olinuxino-lime2.dts-        gpio = <&pio 2 17 GPIO_ACTIVE_HIGH>;
> > ./sun7i-a20-olinuxino-lime2.dts-        status = "okay";
> > ./sun7i-a20-olinuxino-lime2.dts-};  
> 
> IIRC, the AXP209 typically used with these boards doesn't have a
> N_VBUSEN line

According to the Lime2 schematic and the AXP209 data sheet from the Wiki
it does have N_VBUSEN, from a quick glance with the usual
functionality. And the connection on the Lime2 looks indeed the same,
USB0_DRVVBUS connected to both the PMIC and a GPIO.
(Also the BPi-M2 Ultra has an AXP221 anyway.)

I would lean towards Chen-Yu's suggestion (use the PMIC).
It seems like my BPi M2 Berry uses the same layout, so I can do some
experiments later.

Cheers,
Andre