On Wed, May 04, 2016 at 04:47:18PM +0300, Roger Quadros wrote: > On 04/05/16 16:17, Rob Herring wrote: > > On Mon, May 02, 2016 at 03:18:53PM +0300, Roger Quadros wrote: > >> From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> > >> > >> Since some host controller (e.g. EHCI) needs a companion host controller > >> (e.g. OHCI), this patch adds such a configuration to use it in the OTG > >> core. > >> > >> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx> > >> Signed-off-by: Roger Quadros <rogerq@xxxxxx> > >> --- > >> Documentation/devicetree/bindings/usb/generic.txt | 3 +++ > >> drivers/usb/common/usb-otg.c | 32 ++++++++++++++++------- > >> include/linux/usb/otg.h | 7 ++++- > >> 3 files changed, 32 insertions(+), 10 deletions(-) > >> > >> diff --git a/Documentation/devicetree/bindings/usb/generic.txt b/Documentation/devicetree/bindings/usb/generic.txt > >> index f6866c1..1db1c33 100644 > >> --- a/Documentation/devicetree/bindings/usb/generic.txt > >> +++ b/Documentation/devicetree/bindings/usb/generic.txt > >> @@ -27,6 +27,9 @@ Optional properties: > >> - otg-controller: phandle to otg controller. Host or gadget controllers can > >> contain this property to link it to a particular OTG > >> controller. > >> + - hcd-needs-companion: must be present if otg controller is dealing with > >> + EHCI host controller that needs a companion OHCI host > >> + controller. > > > > Don't you need to have a link to the companion controller node? > > primary and companion controllers are totally independent of each other > e.g. EHCI and OHCI. They are enabled by separate Kconfig options and > the system can operate with either or both of them enabled. > > At the OTG layer we don't have information as to whether we should be waiting > for both of them to register or not and hence need this "hcd-needs-companion" flag. What I mean is if you have 2 EHCI controllers with 2 companion controllers, don't you need to know which companion goes with which EHCI controller? Just like you do for the otg-controller property. Rob -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
