Re: [PATCH v6] usb: common: add API to set usb otg capabilities by device tree

[Li Jun <b47624-KZfg59tc24xl57MIdRCFDg@public.gmane.org>]

On Mon, Jun 22, 2015 at 12:43:37PM +0300, Roger Quadros wrote:
> On Thu, 18 Jun 2015 16:47:48 +0800
> Li Jun <b47624-KZfg59tc24xl57MIdRCFDg@public.gmane.org> wrote:
> 
> > On Thu, Jun 18, 2015 at 10:36:50AM +0300, Roger Quadros wrote:
> > > Lin,
> > > 
> > > You can use --in-reply-to "message id of v5 of this path" so that it appears together
> > > with the other patches in peoples mailboxes.
> > > 
> > > > + * the passed properties in DT.
> > > > + * @np: Pointer to the given device_node
> > > > + * @otg_caps: Pointer to the target usb_otg_caps to be set
> > > > + *
> > > > + * The function gets and sets the otg capabilities
> > > > + */
> > > > +void of_usb_set_otg_caps(struct device_node *np, struct usb_otg_caps *otg_caps)
> > > > +{
> > > > +	u32 otg_rev;
> > > > +
> > > > +	if (!otg_caps)
> > > > +		return;
> > > > +
> > > > +	if (!of_property_read_u32(np, "otg-rev", &otg_rev))
> > > > +		otg_caps->otg_rev = otg_rev;
> > > 
> > > should we check if otg_rev is in correct format?
> > > anything non BCD and greater than 0x9999 is invalid.
> > > 
> > > Also if otg-rev is not passed then we need to treat it as legacy
> > > platform right? How is this taken care of?
> > > 
> > Missed this comment
> > This handling rely on controller driver, cannot decided here.
> > There are several cases we need take care:
> > 1) otg-rev is not passed, but all 3 disable flags passed, this is
> >   valid, means user want to disable whole OTG, so only "otg-rev"
> >   not passed, cannot treat as legacy platform.
> > 2) Legacy platform means: none of 4 properties is present.
> 
> OK this was our difference in understanding. I was thinking that for non
> legacy code otg-rev _must_ be passed. without otg-rev the disable flags
> will be ignored. It makes life much easier no?
> 

I have to consider ID pint detect case, this is a most common usage,
after controller driver use otg_caps and enable OTG HNP/SRP, some
platform still just want ID pin detect, no more otg feature required,
it need disable OTG HNP/SRP/ADP, the dt should be:
dr_mode = "otg";
adp-disable;
hnp-disable;
srp-didable;

in this case, we cannot require DT user still pass a otg-rev, right?

> why do you want otg-rev to be optional for non-legacy DT?
> 

For above ID pin detect case.

> > 3) Some controller drivers already support OTG HNP/SRP, then change
> >   to utilize those new flags, still should support OTG HNP/SRP w/o
> >   any dt change, so OTG caps should be enabled for legacy platforms.
> > 4) Some controller drivers does not support any OTG, after add OTG
> >   functions and utilize those new flags, should keep OTG disabled
> >   for legacy platforms.
> > 
> 
> cheers,
> -roger
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in