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From:   Doug Anderson <dianders@chromium.org>
Date:   Tue, 17 Jul 2018 16:55:10 -0700
Message-ID: <CAD=FV=WydRLs1pY_N+whP10qkqmu8tySPictRuxsLvrfdunFcg@mail.gmail.com>
Subject: Re: [PATCH v7 3/7] arm64: dts: msm8996: thermal: Initialise via DT
 and add second controller
To:     Matthias Kaehlcke <mka@chromium.org>
Cc:     Amit Kucheria <amit.kucheria@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Rajendra Nayak <rnayak@codeaurora.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Eduardo Valentin <edubezval@gmail.com>,
        smohanad@codeaurora.org,
        Vivek Gautam <vivek.gautam@codeaurora.org>,
        Andy Gross <andy.gross@linaro.org>,
        David Brown <david.brown@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        "open list:ARM/QUALCOMM SUPPORT" <linux-soc@vger.kernel.org>,
        devicetree@vger.kernel.org,
        Linux ARM <linux-arm-kernel@lists.infradead.org>
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Hi,

On Tue, Jul 17, 2018 at 4:42 PM, Matthias Kaehlcke <mka@chromium.org> wrote:
> On Thu, Jul 12, 2018 at 02:09:04PM +0530, Amit Kucheria wrote:
>> We also split up the regmap address space into two, for the TM and SROT
>> registers. This was required to deal with different address offsets for the
>> TM and SROT registers across different SoC families.
>>
>> 8996 has two TSENS IP blocks, initialise the second one too.
>>
>> Since tsens-common.c/init_common() currently only registers one address
>> space, the order is important (TM before SROT). This is OK since the code
>> doesn't really use the SROT functionality yet.
>>
>> Signed-off-by: Amit Kucheria <amit.kucheria@linaro.org>
>> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
>> Tested-by: Matthias Kaehlcke <mka@chromium.org>
>> ---
>>  arch/arm64/boot/dts/qcom/msm8996.dtsi | 14 ++++++++++++--
>>  1 file changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm64/boot/dts/qcom/msm8996.dtsi b/arch/arm64/boot/dts/qcom/msm8996.dtsi
>> index 8c7f9ca..688e752 100644
>> --- a/arch/arm64/boot/dts/qcom/msm8996.dtsi
>> +++ b/arch/arm64/boot/dts/qcom/msm8996.dtsi
>> @@ -459,9 +459,19 @@
>>                       status = "disabled";
>>               };
>>
>> -             tsens0: thermal-sensor@4a8000 {
>> +             tsens0: thermal-sensor@4a9000 {
>                                        ~~~~~~
>
> I suppose the address of the TM block is used here instead of the SROT
> address (which is lower) since SROT functionality is currently not
> used. Would/should this change if/when the driver uses SROT?

For device tree you're always supposed to use the address of the first
"reg" listed as the unit address in the node name.  It doesn't matter
if it's bigger or smaller as long as it's the first one listed.

The bindings indicate that the TM block should be listed as the first
register.  This won't change even if you start using SROT.


-Doug