linux-kernel - Re: [PATCH v8 10/14] usb: otg: add hcd companion support

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Message-ID: <573980EA.10901@ti.com>
Date:	Mon, 16 May 2016 11:12:26 +0300
From:	Roger Quadros <rogerq@...com>
To:	Rob Herring <robh@...nel.org>
CC:	Peter Chen <peter.chen@...escale.com>, <balbi@...nel.org>,
	Tony Lindgren <tony@...mide.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Dan Williams <dan.j.williams@...el.com>,
	Mathias Nyman <mathias.nyman@...ux.intel.com>,
	Joao Pinto <Joao.Pinto@...opsys.com>,
	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>,
	Li Jun <jun.li@...escale.com>,
	Grygorii Strashko <grygorii.strashko@...com>,
	"Shimoda, Yoshihiro" <yoshihiro.shimoda.uh@...esas.com>,
	Sekhar Nori <nsekhar@...com>, Bin Liu <b-liu@...com>,
	Linux USB List <linux-usb@...r.kernel.org>,
	linux-omap <linux-omap@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>
Subject: Re: [PATCH v8 10/14] usb: otg: add hcd companion support

On 13/05/16 21:13, Rob Herring wrote:
> On Fri, May 13, 2016 at 5:03 AM, Roger Quadros <rogerq@...com> wrote:
>> From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.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@...esas.com>
>> Signed-off-by: Roger Quadros <rogerq@...com>
>> Acked-by: Peter Chen <peter.chen@....com>
>> ---
>>  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.
> 
> I thought the conclusion was this is not needed?

This is still needed to differentiate between primary+shared HCD case vs
primary + primary-companion HCD case.

> 
> One thing that is not clear here is otg-controller is a host or device
> property while hcd-needs-companion is an OTG controller property.
> These lists should be separated.

Agreed. I'll fix that up.

cheers,
-roger