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

Yang, Wenyou
2016-06-17T13:44:32Z

Hi Alexandre,

> -----Original Message-----
> From: Alexandre Belloni [mailto:alexandre.belloni@free-electrons.com]
> Sent: 2016年6月9日 4:38
> To: Rob Herring <robh@kernel.org>
> Cc: Yang, Wenyou <Wenyou.Yang@atmel.com>; Alan Stern
> <stern@rowland.harvard.edu>; Greg Kroah-Hartman
> <gregkh@linuxfoundation.org>; Ferre, Nicolas <Nicolas.FERRE@atmel.com>;
> Pawel Moll <pawel.moll@arm.com>; Mark Brown <broonie@kernel.org>; Ian
> Campbell <ijc+devicetree@hellion.org.uk>; Kumar Gala <galak@codeaurora.org>;
> linux-kernel@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-usb@vger.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@atmel.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.

Could you give some advice?.

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

Best Regards,
Wenyou Yang