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

[Chen-Yu Tsai <wens@csie.org>]

On Mon, Jul 5, 2021 at 11:51 AM qianfan <qianfanguijin@163.com> wrote:
> 在 2021/7/2 20:30, Chen-Yu Tsai 写道:
> > On Fri, Jul 2, 2021 at 8:24 PM Andre Przywara <andre.przywara@arm.com> wrote:
> >> 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.)
> > The difference is that the N_VBUSEN pin on the AXP221 can be used as an
> > output, while on the AXP209 it is strictly an input. And U-Boot tends
> > to leave pins it has used in whatever state last used so ideally we
> > need to coordinate both to use the same method. Otherwise you might
> > end up with N_VBUSEN always driving DRVVBUS high or low, and the GPIO
> > on the SoC not having any effect. Ideally we need some way to reset
> > the state of the pins to high-Z.
> >
> > ChenYu
>
> I had changed the dts to control VBUS by using PMIC, but I had a
> question: what's the perpose of
>
> the gpio?

Which GPIO? You mean the one on the SoC wired to N_VBUSEN and DRVVBUS?
Or N_VBUSEN itself?

ChenYu