Re: [PATCH v3 2/4] misc: hisi_hikey_usb: change the DT schema
From: Mauro Carvalho Chehab
Date: Thu Sep 02 2021 - 10:35:39 EST
Em Thu, 2 Sep 2021 15:56:36 +0200
Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> escreveu:
> On Thu, Sep 02, 2021 at 03:38:20PM +0200, Mauro Carvalho Chehab wrote:
> > Em Thu, 2 Sep 2021 15:10:53 +0200
> > Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx> escreveu:
> > > Em Thu, 2 Sep 2021 13:40:28 +0200
> > > Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> escreveu:
> > >
> > > > On Thu, Sep 02, 2021 at 01:28:35PM +0200, Mauro Carvalho Chehab wrote:
> > > > > As there's no upstream DT bindings for this driver, let's
> > > > > update its DT schema, while it is not too late.
> > > >
> > > > So this is for 5.15-final?
> > >
> > > It can either be for 5.15 or 5.16, as there aren't any compatible
> > > under arch/ which uses the DT schema there. All patches adding
> > > such compatible are on this series. So, whatever version this
> > > is applied should be OK.
> > On a separate note, despite having "hisi_" on this driver's name, there's
> > nothing there that is really HiSilicon specific. What this driver does is
> > to control an USB HUB integrated inside a DT-based board, doing those
> > functions:
> > - Power on/off the chip;
> > - reset the HUB;
> > - control its OTG switch;
> > - control power on/off for an USB type-C connector;
> > - set USB role as host or device.
> > This is used on both HiKey 960 and HiKey 970 with the following
> > topology:
> > +-----+ +--------+ +---------+
> > | SoC | ---> | USB PHY| ---> | USB HUB | ---> USB 3.0
> > +-----+ +--------+ +---------+ and type-C ports
> > Both Kirin 960 and 970 SoCs have a Synapsys IP (DWC 3).
> > Both HiKey 960 and 970 cards use Richtek RT1711H Type-C Chip Driver
> > as part of the USB PHY logic, but they use different USB HUBs:
> > - HiKey 960 use a Microchip USB5734 HUB
> > - HiKey 970 use a TI TUSB8041 HUB
> > While I'm not sure how generic this driver can be, I'm thinking that
> > maybe a future patch could rename it to 'generic-usb-hub' or
> > something similar - finding a good name is always the hardest
> > part :-)
> Try looking at:
> for another example of this.
(C/C Matthias here).
Interesting to know that someone else is also needing to add support
for USB chips.
Yet, the approach took there won't work with HiKey 960/970, as
it needs to control not only the regulator, but it should also
work as as usb-role-switch.
So, besides controlling the regulator, which seems to be basically what
the onboard_usb_hub_driver does, but it should also be able to:
- (optionally) reset the HUB;
- control its OTG switch;
- control power on/off for an USB type-C connector;
- set USB role as host or device.
Perhaps it would be possible to merge both approaches by modifying
hisi_hikey_usb in order to add the extra bits required by the boards that
Matthias is currently working, and requiring the GPIOs for OTG and
type-C connectors only if DT contains usb-role-switch.