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From: Stephen Boyd <swboyd@chromium.org>
To: Doug Anderson <dianders@chromium.org>,
	Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
	<devicetree@vger.kernel.org>,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Rob Herring <robh+dt@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Andy Gross <agross@kernel.org>,
	Guenter Roeck <groeck@chromium.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 1/3] arm64: dts: qcom: sc7180: Add APSS watchdog node
Date: Mon, 16 Dec 2019 08:51:13 -0800	[thread overview]
Message-ID: <5df7b601.1c69fb81.f092b.26d7@mx.google.com> (raw)
In-Reply-To: <CAD=FV=X3Akg07hetQOgd0P_wTVWs3QpuCNQ8O6qQ5LK2ZeWSaQ@mail.gmail.com>

Quoting Doug Anderson (2019-12-11 11:25:23)
> On Tue, Dec 10, 2019 at 8:30 PM Sai Prakash Ranjan
> <saiprakash.ranjan@codeaurora.org> wrote:
> 
> Unrelated to sc7180, but it also feels like something is awfully
> screwy here in terms of the various Qualcomm device tree files
> referring to watchdog timers.  It feels wrong, but perhaps you can
> educate me on how it works and I'll see the light.  Specifically:
> 
> 1. It seems like the same node is used for two things on other Qualcomm SoCs
> 
> If I grep the bindings for "qcom,kpss-timer" or "qcom,scss-timer", I
> get two hits:
> 
> Documentation/devicetree/bindings/timer/qcom,msm-timer.txt
> Documentation/devicetree/bindings/watchdog/qcom-wdt.txt
> 
> ...and, in fact, there appear to be two drivers claiming compatibility here:
> 
> drivers/clocksource/timer-qcom.c
> drivers/watchdog/qcom-wdt.c
> 
> That seems super odd to me.  Is that really right?  We have two
> drivers probing against the same device tree nodes?  ...and that's OK?
>  If so, why does only one of the bindings list the SoC-specific
> bindings names?

The drivers/clocksource/timer-qcom.c file isn't a "driver", at least not
in the linux device driver model. It's a clocksource driver that probes
early so in this case the clocksource code runs early and then the
qcom-wdt driver probes later as a platform device driver.


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      parent reply	other threads:[~2019-12-16 16:51 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cover.1576037078.git.saiprakash.ranjan@codeaurora.org>
2019-12-11  4:30 ` [PATCH 1/3] arm64: dts: qcom: sc7180: Add APSS watchdog node Sai Prakash Ranjan
2019-12-11  4:30 ` [PATCH 2/3] arm64: dts: qcom: sm8150: " Sai Prakash Ranjan
2019-12-11  4:30 ` [PATCH 3/3] arm64: dts: qcom: sc7180: Add Last level cache controller node Sai Prakash Ranjan
     [not found] ` <0101016ef3391ded-57772416-f32d-40e8-acb5-5dd1b6064f73-000000@us-west-2.amazonses.com>
2019-12-11 19:25   ` [PATCH 1/3] arm64: dts: qcom: sc7180: Add APSS watchdog node Doug Anderson
2019-12-13  4:31     ` saiprakash.ranjan
2019-12-16 16:51     ` Stephen Boyd [this message]

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