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

[qianfan <qianfanguijin@163.com>]

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?

>
>> 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.