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From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh@kernel.org>,
	linuxarm@huawei.com, mauro.chehab@huawei.com,
	John Stultz <john.stultz@linaro.org>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-kernel@vger.kernel.org,
	Matthias Kaehlcke <mka@chromium.org>
Subject: Re: [PATCH v3 2/4] misc: hisi_hikey_usb: change the DT schema
Date: Thu, 2 Sep 2021 16:35:29 +0200	[thread overview]
Message-ID: <20210902163529.734b8e0e@coco.lan> (raw)
In-Reply-To: <YTDYFCH/DbK1SFVv@kroah.com>

Em Thu, 2 Sep 2021 15:56:36 +0200
Greg Kroah-Hartman <gregkh@linuxfoundation.org> 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@kernel.org> escreveu:
> >   
> > > Em Thu, 2 Sep 2021 13:40:28 +0200
> > > Greg Kroah-Hartman <gregkh@linuxfoundation.org> 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:
> 	https://lore.kernel.org/r/20210813195228.2003500-1-mka@chromium.org
> 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.

Thanks,
Mauro

  reply	other threads:[~2021-09-02 14:35 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-02 11:28 [PATCH v3 0/4] Make USB ports to work on HiKey960/970 Mauro Carvalho Chehab
2021-09-02 11:28 ` [PATCH v3 1/4] dt-bindings: misc: add schema for USB hub on Kirin devices Mauro Carvalho Chehab
2021-09-02 11:28 ` [PATCH v3 2/4] misc: hisi_hikey_usb: change the DT schema Mauro Carvalho Chehab
2021-09-02 11:40   ` Greg Kroah-Hartman
2021-09-02 13:10     ` Mauro Carvalho Chehab
2021-09-02 13:38       ` Mauro Carvalho Chehab
2021-09-02 13:56         ` Greg Kroah-Hartman
2021-09-02 14:35           ` Mauro Carvalho Chehab [this message]
2021-09-02 17:28             ` Matthias Kaehlcke
2021-09-02 18:29               ` John Stultz
2021-09-02 20:03                 ` Matthias Kaehlcke
2021-09-02 20:31                   ` John Stultz
2021-09-02 21:34                     ` Matthias Kaehlcke
2021-09-02 21:42                     ` Mauro Carvalho Chehab
2021-09-02 18:45   ` John Stultz
2021-09-02 11:28 ` [PATCH v3 3/4] arm64: dts: hisilicon: Add usb mux hub for hikey970 Mauro Carvalho Chehab
2021-09-02 11:28 ` [PATCH v3 4/4] arm64: dts: hisilicon: Add usb mux hub for hikey960 Mauro Carvalho Chehab

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