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Date:   Fri, 23 Dec 2022 17:16:38 -0600
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Subject: Re: [PATCH v2] arm64: dts: qcom: sc7280: enable IPA in
 sc7280-herobrine-lte-sku.dtsi
To:     Doug Anderson <dianders@chromium.org>,
        Matthias Kaehlcke <mka@chromium.org>
Cc:     Alex Elder <elder@linaro.org>, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, andersson@kernel.org,
        konrad.dybcio@linaro.org, agross@kernel.org,
        quic_sibis@quicinc.com, elder@kernel.org,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20221215224552.1232449-1-elder@linaro.org>
 <Y5vDXm4oo2cn3etX@google.com>
 <CAD=FV=XsUXCzjKbLvOd7M-CPQi13pf9dvpvLwLQnsoL0m-5xCQ@mail.gmail.com>
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From:   Alex Elder <elder@ieee.org>
In-Reply-To: <CAD=FV=XsUXCzjKbLvOd7M-CPQi13pf9dvpvLwLQnsoL0m-5xCQ@mail.gmail.com>
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On 12/22/22 4:39 PM, Doug Anderson wrote:
> Hi,
> 
> On Thu, Dec 15, 2022 at 5:01 PM Matthias Kaehlcke <mka@chromium.org> wrote:
>>
>> On Thu, Dec 15, 2022 at 04:45:52PM -0600, Alex Elder wrote:
>>
>>> Subject: arm64: dts: qcom: sc7280: enable IPA in sc7280-herobrine-lte-sku.dtsi

I'll post an update with your suggested subject line.

Thanks!

					-Alex

>>
>> nit: that sounds as if IPA wasn't enabled previously. It would be
>> clearer to say something like: "sc7280: only enable IPA for boards
>> with a modem".
>>
>>> IPA is only needed on a platform if it includes a modem, and not all
>>> SC7280 SoC variants do.  The file "sc7280-herobrine-lte-sku.dtsi" is
>>> used to encapsulate definitions related to Chrome OS SC7280 devices
>>> where a modem is present, and that's the proper place for the IPA
>>> node to be enabled.
>>>
>>> Currently IPA is enabled in "sc7280-idp.dtsi", which is included by
>>> DTS files for Qualcomm reference platforms (all of which include the
>>> modem).  That also includes "sc7280-herobrine-lte-sku.dtsi", so
>>> enabling IPA there would make it unnecessary for "sc7280-idp.dtsi"
>>> to enable it.
>>>
>>> The only other place IPA is enabled is "sc7280-qcard.dtsi".
>>> That file is included only by "sc7280-herobrine.dtsi", which
>>> is (eventually) included only by these top-level DTS files:
>>>    sc7280-herobrine-crd.dts
>>>    sc7280-herobrine-herobrine-r1.dts
>>>    sc7280-herobrine-evoker.dts
>>>    sc7280-herobrine-evoker-lte.dts
>>>    sc7280-herobrine-villager-r0.dts
>>>    sc7280-herobrine-villager-r1.dts
>>>    sc7280-herobrine-villager-r1-lte.dts
>>> All of but two of these include "sc7280-herobrine-lte-sku.dtsi", and
>>> for those cases, enabling IPA there means there is no need for it to
>>> be enabled in "sc7280-qcard.dtsi".
>>>
>>> The two remaining cases will no longer enable IPA as a result of
>>> this change:
>>>    sc7280-herobrine-evoker.dts
>>>    sc7280-herobrine-villager-r1.dts
>>> Both of these have "lte" counterparts, and are meant to represent
>>> board variants that do *not* have a modem.
>>>
>>> This is exactly the desired configuration.
>>>
>>> Signed-off-by: Alex Elder <elder@linaro.org>
>>> Reviewed-by: Sibi Sankar <quic_sibis@quicinc.com>
>>> Tested-by: Sibi Sankar <quic_sibis@quicinc.com>
>>
>> Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
> 
> I'd agree that the subject like proposed by Matthias sounds better. In any case:
> 
> Reviewed-by: Douglas Anderson <dianders@chromium.org>