linux-kernel - Re: [PATCH v3 1/2] usb: ohci-at91: Forcibly suspend ports while USB suspend

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Date:	Wed, 8 Jun 2016 22:38:10 +0200
From:	Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:	Rob Herring <robh@...nel.org>
Cc:	Wenyou Yang <wenyou.yang@...el.com>,
	Alan Stern <stern@...land.harvard.edu>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Nicolas Ferre <nicolas.ferre@...el.com>,
	Pawel Moll <pawel.moll@....com>,
	Mark Brown <broonie@...nel.org>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH v3 1/2] usb: ohci-at91: Forcibly suspend ports while USB
 suspend

On 08/06/2016 at 15:26:51 -0500, Rob Herring wrote :
> On Wed, Jun 08, 2016 at 12:15:10PM +0800, Wenyou Yang wrote:
> > In order to the save power consumption, as a workaround, suspend
> > forcibly the USB PORTA/B/C via set the SUSPEND_A/B/C bits of OHCI
> > Interrupt Configuration Register in the SFRs while OHCI USB suspend.
> > 
> > This suspend operation must be done before the USB clock is disabled,
> > resume after the USB clock is enabled.
> > 
> > Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
> > ---
> > 
> > Changes in v3:
> >  - Change the compatible description for more precise.
> > 
> > Changes in v2:
> >  - Add compatible to support forcibly suspend the ports.
> >  - Add soc/at91/at91_sfr.h to accommodate the defines.
> >  - Add error checking for .sfr_regmap.
> >  - Remove unnecessary regmap_read() statement.
> > 
> >  .../devicetree/bindings/usb/atmel-usb.txt          |  6 +-
> >  drivers/usb/host/ohci-at91.c                       | 80 +++++++++++++++++++++-
> >  include/soc/at91/at91_sfr.h                        | 29 ++++++++
> >  3 files changed, 112 insertions(+), 3 deletions(-)
> >  create mode 100644 include/soc/at91/at91_sfr.h
> > 
> > diff --git a/Documentation/devicetree/bindings/usb/atmel-usb.txt b/Documentation/devicetree/bindings/usb/atmel-usb.txt
> > index 5883b73..888deaa 100644
> > --- a/Documentation/devicetree/bindings/usb/atmel-usb.txt
> > +++ b/Documentation/devicetree/bindings/usb/atmel-usb.txt
> > @@ -3,8 +3,10 @@ Atmel SOC USB controllers
> >  OHCI
> >  
> >  Required properties:
> > - - compatible: Should be "atmel,at91rm9200-ohci" for USB controllers
> > -   used in host mode.
> > + - compatible: Should be one of the following
> > +	       "atmel,at91rm9200-ohci" for USB controllers used in host mode.
> > +	       "atmel,sama5d2-ohci" for USB controllers used in host mode
> > +	       on SAMA5D2 which can force to suspend.
> 
> Guess I wasn't clear enough before. Drop "which can force to suspend".
> 

Well, my point is that we don't need a new compatible anyway.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com