Subject: [PATCH v2 1/6] binding-doc: power: pwrseq-generic: add binding doc for generic power sequence library

From: [email-masked] (Peter Chen)
Date: Wed, 13 Jul 2016 16:42:50 +0800

On Wed, Jul 13, 2016 at 09:27:31AM +0200, Philipp Zabel wrote:
> Am Mittwoch, den 13.07.2016, 10:06 +0800 schrieb Peter Chen:
> > Add binding doc for generic power sequence library.
> > 
> > Signed-off-by: Peter Chen <[email-masked]>
> > ---
> >  .../bindings/power/pwrseq/pwrseq-generic.txt       | 53 ++++++++++++++++++++++
> >  1 file changed, 53 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> > 
> > diff --git a/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> > new file mode 100644
> > index 0000000..186c58c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/power/pwrseq/pwrseq-generic.txt
> > @@ -0,0 +1,53 @@
> > +The generic power sequence library
> > +
> > +Some hard-wired USB/MMC devices need to do power sequence to let the
> > +device work normally,
> 
> I would replace "to let the device work normally" with "before the
> device can be enumerated [on the bus]" here.
> 

Ok.

> >  the typical power sequence like: enable USB
> > +PHY clock, toggle reset pin, etc. But current Linux USB driver
> > +lacks of such code to do it, it may cause some hard-wired USB devices
> > +works abnormal or can't be recognized by controller at all. The
> > +power sequence will be done before this device can be found at USB
> > +bus.
> > +
> > +The power sequence properties is under the device node.
> > +
> > +Required properties:
> > +- power-sequence: this device needs to do power sequence before enumeration
> 
> As Joshua pointed out, is this even needed at all?
> 

If no, how we decide whether allocates pwrseq instance through pwrseq
library or not?

-- 

Best Regards,
Peter Chen