Re: [PATCH 5/8] Revert "dt-bindings: usb: dwc3: Add wakeup-source property support"

From: Johan Hovold <johan@kernel.org>
To: Rob Herring <robh@kernel.org>
Cc: Johan Hovold <johan+linaro@kernel.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Felipe Balbi <balbi@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
	Konrad Dybcio <konrad.dybcio@somainline.org>,
	Krishna Kurapati <quic_kriskura@quicinc.com>,
	Stephen Boyd <swboyd@chromium.org>,
	Doug Anderson <dianders@chromium.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Pavankumar Kondeti <quic_pkondeti@quicinc.com>,
	quic_ppratap@quicinc.com, quic_vpulyala@quicinc.com,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	Linux USB List <linux-usb@vger.kernel.org>,
	devicetree@vger.kernel.org,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/8] Revert "dt-bindings: usb: dwc3: Add wakeup-source property support"
Date: Thu, 4 Aug 2022 07:47:35 +0200	[thread overview]
Message-ID: <Yutdd7kWx2sc1yQu@hovoldconsulting.com> (raw)
In-Reply-To: <20220803232644.GA2806113-robh@kernel.org>

On Wed, Aug 03, 2022 at 05:26:44PM -0600, Rob Herring wrote:
> On Wed, Aug 03, 2022 at 09:31:06AM +0200, Johan Hovold wrote:
> > On Tue, Aug 02, 2022 at 11:17:22AM -0600, Rob Herring wrote:
> > > On Tue, Aug 2, 2022 at 9:14 AM Johan Hovold <johan+linaro@kernel.org> wrote:
> > 
> > > > It should also not be used to
> > > > work around Linux driver implementation issues such as how to coordinate
> > > > the glue and core dwc3 drivers.
> > > >
> > > > For the Qualcomm dwc3 controllers, it is the glue device that manages
> > > > the wakeup interrupts, which may or may not be able to wake the system
> > > > up from system suspend.
> > > 
> > > While the reasoning to add this may have been for QCom, having this
> > > property for other users makes sense. On some platforms, 'snps,dwc3'
> > > is the only node (i.e. there's no wrapper node). So I don't think this
> > > should be reverted.
> > 
> > Fair enough. Let's keep it in the core child node then where we can
> > still retrieve from the glue parent directly.
> > 
> > (I assume you're not suggesting also adding 'wakeup-source' to the qcom
> > glue node, which is where the actual wakeup interrupts live.)
> 
> 'wakeup-source' belongs wherever the interrupt that causes wakeup is 
> defined.

Thanks for clarifying. That was my understanding as well, but I
misinterpreted your wish to keep the 'wakeup-source' property also in
the core node.

My thought was that if it turns out that there are systems that do not
use a glue node but that do indeed support wakeup, then such a property
could be added back later.

But let's keep it in the binding then.

Johan