On Wed, May 04, 2016 at 04:47:18PM +0300, Roger Quadros wrote:

On 04/05/16 16:17, Rob Herring wrote:

quoted

On Mon, May 02, 2016 at 03:18:53PM +0300, Roger Quadros wrote:

quoted

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

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@renesas.com>
Signed-off-by: Roger Quadros <redacted>
---
 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