Re: [PATCH v5 2/2] usb: chipidea: imx: Add binding to disable USB 60Mhz clock

[Fabien Lahoudere]

Hi,

On 26/09/16 10:18, Sascha Hauer wrote:
> On Wed, Sep 21, 2016 at 11:07:07AM +0200, Fabien Lahoudere wrote:
> > This binding allow to disable the internal 60Mhz clock for USB host2 or
> > host3.
> >
> > Signed-off-by: Fabien Lahoudere <fabien.lahoudere@xxxxxxxxxxxxxxx>
> > ---
> >  Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt |  1 +
> >  drivers/usb/chipidea/ci_hdrc_imx.c                     |  2 ++
> >  drivers/usb/chipidea/ci_hdrc_imx.h                     |  1 +
> >  drivers/usb/chipidea/usbmisc_imx.c                     | 13 +++++++++++++
> >  4 files changed, 17 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> > index 0e03344..f83da66 100644
> > --- a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> > +++ b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> > @@ -84,6 +84,7 @@ i.mx specific properties
> >  - over-current-active-high: over current signal polarity is high active,
> >    typically over current signal polarity is low active.
> >  - external-vbus-divider: enables off-chip resistor divider for Vbus
> > +- disable-int60ck: disable internal 60MHz clock for usb host2 or host3 on imx53
>
> Why do we need a binding for this? I would assume the driver should know
> whether this clock is in use or not. If it doesn't that's a problem we
> should solve.

Yes you are right because we can disable this clock for OTG and with 
ULPI PHY. I think that it will be better to have a dt binding but if it 
is useless I can remove it and disable clock when ULPI mode is enabled.

> Sascha

Fabien