Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759658AbcKCRvM (ORCPT ); Thu, 3 Nov 2016 13:51:12 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:34771 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759218AbcKCRvI (ORCPT ); Thu, 3 Nov 2016 13:51:08 -0400 Subject: Re: [PATCH v3 3/5] dt/bindings: Add a new property to DA8xx USB PHY To: Alexandre Bailon , , , References: <1478186765-19840-1-git-send-email-abailon@baylibre.com> <1478186765-19840-4-git-send-email-abailon@baylibre.com> <73d3cf2c-2653-15a3-9fa6-755bed419ec2@baylibre.com> CC: , , , From: Kishon Vijay Abraham I Message-ID: <8e3c9209-9db0-c288-5b3d-3d29f1571e47@ti.com> Date: Thu, 3 Nov 2016 23:20:16 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <73d3cf2c-2653-15a3-9fa6-755bed419ec2@baylibre.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2808 Lines: 69 Hi, On Thursday 03 November 2016 10:56 PM, Alexandre Bailon wrote: > On 11/03/2016 05:34 PM, Kishon Vijay Abraham I wrote: >> Hi, >> >> On Thursday 03 November 2016 08:56 PM, Alexandre Bailon wrote: >>> The USB PHY is able to operate in OTG, host or peripheral. >>> Some board may be wired to work act only as host or peripheral. >>> In such case, the dr_mode property of controller must be set to >>> host or peripheral. But doing that will also configure the PHY >>> in host or peripheral mode whereas OTG is able to detect which >>> role the USB controller should take. >>> The PHY's host or peripheral mode are actually only useful when >>> hardware doesn't allow OTG to detect it's role. >>> >>> Add the usb20_force_mode property to force the PHY to operate >>> in host or peripheral mode. >> >> I think we do just that if we populate dr_mode with host or peripheral. Why do >> we need another property to control dr_mode property? > Because the phy doesn't work correctly when it is in host or > device mode. That would be the same even with usb20_force_mode property. How does usb20_force_mode property help? Thanks Kishon >>> When usb20_force_mode is used, dr_mode should also be configured >>> to host or peripheral. >>> The controller uses dr_mode to configure itself, but the phy use >>> it to get the mode to use to configure the PHY mode. >>> >>> Signed-off-by: Alexandre Bailon >>> --- >>> Documentation/devicetree/bindings/phy/phy-da8xx-usb.txt | 5 +++++ >>> 1 file changed, 5 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/phy/phy-da8xx-usb.txt b/Documentation/devicetree/bindings/phy/phy-da8xx-usb.txt >>> index c26478b..9fc87fb 100644 >>> --- a/Documentation/devicetree/bindings/phy/phy-da8xx-usb.txt >>> +++ b/Documentation/devicetree/bindings/phy/phy-da8xx-usb.txt >>> @@ -4,6 +4,11 @@ Required properties: >>> - compatible: must be "ti,da830-usb-phy". >>> - #phy-cells: must be 1. >>> >>> +Optional properties: >>> +- usb20-force-mode: Force the phy to operate in same mode than the USB OTG controller. >>> + It should only be defined if the hardware is not capable correctly >>> + detect the role of USB by using VBUS and ID pin. >> >> From what I understand from the previous patch, if VBUS sense and the session >> end comparator is enabled, the controller can work in host mode or device mode. > I but VBUS sense and and session end comparator only seems to work when > the phy is in otg mode. > In host mode, the phy stop to work after the first disconnect. > In device mode, the phy never detect a disconnect. > In otg mode, these issues go away. > I'm working on workaround for both of them but I think it is > better to keep the phy in otg when it is possible. >> >> Thanks >> Kishon >> > Thanks, > Alexandre >