Re: [PATCH v3 1/3] usb: chipidea: imx: support configuring for active low oc signal

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello Stefan,

On Tue, Dec 04, 2018 at 09:40:26AM +0100, Stefan Wahren wrote:
> Am 04.12.18 um 09:31 schrieb Uwe Kleine-König:
> > The status quo on i.MX6 is that if "over-current-active-high" is
> > specified in the device tree this is configured as expected. If
> > the property is missing polarity isn't changed and so the
> > polarity is kept as setup by the bootloader. Reset default is
> > active high, so active low can only be used with help by the
> > bootloader. On i.MX7 it is similar, but there disabling of
> > over current detection has a similar inconsistency.
> >
> > This patch introduces a new property that allows to explicitly
> > configure for active low over current detection and consistently
> > sets this up. In the absence of an explicit configuration the
> > bit is kept as is. On i.MX7 over current detection is used unless
> > disabled in the device tree.
> >
> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> > ---
> >  .../devicetree/bindings/usb/ci-hdrc-usb2.txt  |  5 ++--
> >  drivers/usb/chipidea/ci_hdrc_imx.c            | 16 ++++++++---
> >  drivers/usb/chipidea/ci_hdrc_imx.h            |  8 +++++-
> >  drivers/usb/chipidea/usbmisc_imx.c            | 28 ++++++++++++++-----
> >  4 files changed, 43 insertions(+), 14 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> > index 529e51879fb2..c32f6e983cf6 100644
> > --- a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> > +++ b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> > @@ -87,8 +87,9 @@ i.mx specific properties
> >  - fsl,usbmisc: phandler of non-core register device, with one
> >    argument that indicate usb controller index
> >  - disable-over-current: disable over current detect
> > -- over-current-active-high: over current signal polarity is high active,
> > -  typically over current signal polarity is low active.
> > +- over-current-active-low: over current signal polarity is active low.
> > +- over-current-active-high: over current signal polarity is active high.
> > +  It's recommended to specify the over current polarity.
> >  - external-vbus-divider: enables off-chip resistor divider for Vbus
> >  
> >  Example:
> 
> thanks for making this configurable. But shouldn't this be a separate
> patch and reviewed by the devicetree guys?

I'm not sure about the separate patch part. My impression is it depends
on the maintainer if a change to the binding (opposed to the
introduction of a binding) should be separate or not.

But for the review you are right, I added the dt people to Cc for them
to comment. In v2 Matthew also noted that he would prefer to handle the
situation when both over-current-active-low and over-current-active-high
were given differently. I think we don't need that as this is a case of
"broken dt" and it doesn't matter much what is done then. (With my patch
we're configuring for active high in that case.) A feedback here would
be great, too.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |



[Index of Archives]     [Device Tree Compilter]     [Device Tree Spec]     [Linux Driver Backports]     [Video for Linux]     [Linux USB Devel]     [Linux PCI Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [XFree86]     [Yosemite Backpacking]


  Powered by Linux