On Thu, 18 Jun 2015 21:37:04 +0800
Li Jun <b47624@xxxxxxxxxxxxx> wrote:
> On Thu, Jun 18, 2015 at 03:07:48PM +0300, Roger Quadros wrote:
> > On Thu, 18 Jun 2015 16:47:48 +0800
> > Li Jun <b47624@xxxxxxxxxxxxx> 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.
> >
> > Right. Plus controller drivers that are not updated to use these otg_caps
> > are also legacy.
> >
> Did not understand the "Plus" case.
> Some of 4 properties is present, but its driver dose not use otg_caps?
yes that is what I meant.
>
> > > 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.
> >
> > I didn't understand this point. If a controller driver is not updated
> > to use otg_caps it is legacy and gadget->otg_caps will be NULL.
> >
> Some of existing chipdea platforms work fine on HNP and SRP , which did
> not use any new flags and properties, after my patch, those platform should
> still enable HNP and SRP without any DT change.
Agreed.
>
> > > 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.
> >
> > If controller drivers don't support OTG. gadget->is_otg and
> > gadget->otg_caps will not be set by them and they don't have to use
> > of_usb_set_otg_caps().
> >
> But after my patch, some time later, this driver adds OTG functions on
> it new platform, it should disable any OTG feature for its legacy
> platforms (none of properties is passed).
That can be decided in of_usb_update_otg_caps().
Controller sets whatever it supports in otg_caps.
of_usb_updade_otg_caps() checks if it is legacy DT (i.e. no otg-rev) and then
overrides to legacy otg_caps.
>
> > So I didn't understand why the decision can't be taken here
> > for non-legacy controller drivers with legacy DT.
> > They will set gadget->otg_caps and gadget->is_otg.
> >
> > If none of the 4 DT flags are passed then we know it is legacy DT
> > and we can limit to legacy behaviour.
> >
> legacy behaviour number is 2, not only one legacy behaviour.
> That's why I leave the otg caps decided by controller drivers.
I'm only suggesting that it be decided at one place i.e. in
of_usb_updade_otg_caps() instead of every controller.
Do you see any problems with that approach?
cheers,
-roger
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