On Mon, 22 Jun 2015 22:36:40 +0800
Li Jun <b47624@xxxxxxxxxxxxx> wrote:
> On Mon, Jun 22, 2015 at 04:32:56PM +0300, Roger Quadros wrote:
> > On Mon, 22 Jun 2015 18:45:37 +0800
> > Li Jun <b47624@xxxxxxxxxxxxx> wrote:
> >
> > > On Mon, Jun 22, 2015 at 12:41:22PM +0300, Roger Quadros wrote:
> > > > 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?
> > > >
> > > The problem is the override policy for legacy platforms.
> > > For case 3) above, we should enable HNP and SRP,
> >
> > case 3 is controller is supporting new flags but DT is not and we want
> > legacy OTG enabled, right?
> > Can't we detect if none of the new otg flags are present then it is legacy DT
> > so use legacy OTG mode?
> >
> Yes, we can. The legacy OTG mode is HNP&SRP is enabled.
>
> > > For case 4) above, after add OTG HNP&SRP support, it should disable HNP and SRP.
> >
> > case 4 is controller was not supporting OTG at all before and now is updated to support
> > OTG. But for such cases isn't dr_mode = "peripheral" in the DT?
> > one example is dwc3 controller.
> >
> > If the dr_mode was "otg" for such case and we want OTG disabled then it is really the DT fault.
>
> It's ID pin detect for dual role switch as many current OTG controllers have.
> not DT fault, its dt only has a dr_mode = "otg".
>
> > We don't need to tackle this case. Just fix up the DT to dr_mode = "peripheral" if
> > OTG behaviour is not needed.
> >
> OTG behaviour is not needed, so we need disable HNP/SRP/ADP. but dr_mode =
> "otg" as it already works fine with ID pin detect.
Do you know which platform has plain non-otg dual-role working as of today
with dr_mode set to "otg"?
For TI platforms none of them have it working currently.
>
> > >
> > > How I make one decision in of_usb_updade_otg_caps()
> > > for above 2 cases?(the otg-rev is 0 for both).
> > >
> >
> > For case 3. otg-rev passed by controller is not 0. otg-rev is just not present in DT.
> >
>
> Current OTG situation is not so simple, so that we can not use one simple
> rule to handle legacy cases in a common place, but for a particular controller
> driver, make decision on this is a simple work, I think.
OK. Let's continue with your apporach. Maybe USB maintainers can give their opinion
as well.
Later if more controllers are trying to do the same thing then we can introduce a helper
function for those controllers.
cheers,
-roger
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