linux-kernel - Re: [PATCH v4 00/13] Support CPU frequency scaling on QCS404

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Date:   Mon, 26 Aug 2019 18:49:56 +0200
From:   Jorge Ramirez <jorge.ramirez-ortiz@...aro.org>
To:     bjorn.andersson@...aro.org, sboyd@...nel.org,
        david.brown@...aro.org, jassisinghbrar@...il.com,
        mark.rutland@....com, mturquette@...libre.com, robh+dt@...nel.org,
        will.deacon@....com, arnd@...db.de, horms+renesas@...ge.net.au,
        heiko@...ech.de, sibis@...eaurora.org,
        enric.balletbo@...labora.com, jagan@...rulasolutions.com,
        olof@...om.net
Cc:     vkoul@...nel.org, niklas.cassel@...aro.org,
        georgi.djakov@...aro.org, amit.kucheria@...aro.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, khasim.mohammed@...aro.org
Subject: Re: [PATCH v4 00/13] Support CPU frequency scaling on QCS404

On 8/26/19 08:54, Jorge Ramirez wrote:
> On 7/31/19 22:29, Jorge Ramirez-Ortiz wrote:
>> The following patchset enables CPU frequency scaling support on the
>> QCS404 (with dynamic voltage scaling).
>>
>> It is important to notice that this functionality will be superseded
>> by Core Power Reduction (CPR), a more accurate form of AVS found on
>> certain Qualcomm SoCs.
>>
>> Some of the changes required to support CPR do conflict with the
>> configuration required for CPUFreq.
>>
>> In particular, the following commit for CPR - already merged - will
>> need to be reverted in order to enable CPUFreq.
>>
>>    Author: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>
>>    Date:   Thu Jul 25 12:41:36 2019 +0200
>>        cpufreq: Add qcs404 to cpufreq-dt-platdev blacklist
>>     
>> Patch 8 "clk: qcom: hfpll: CLK_IGNORE_UNUSED" is a bit controversial;
>> in this platform, this PLL provides the clock signal to a CPU
>> core. But in others it might not.
>>
>> We opted for the minimal ammount of changes without affecting the
>> default functionality: simply bypassing the COMMON_CLK_DISABLE_UNUSED
>> framework and letting the firwmare chose whether to enable or disable
>> the clock at boot. However maybe a DT property and marking the clock
>> as critical would be more appropriate for this PLL. we'd appreciate the
>> maintainer's input on this topic.
>>
>> v2:
>>    - dts: ms8916: apcs mux/divider: new bindings
>>      (the driver can still support the old bindings)
>>
>>    - qcs404.dtsi
>>      fix apcs-hfpll definition
>>      fix cpu_opp_table definition
>>
>>    - GPLL0_AO_OUT operating frequency
>>      define new alpha_pll_fixed_ops to limit the operating frequency
>>
>> v3:
>>   - qcom-apcs-ipc-mailbox
>>     replace goto to ease readability
>>
>>   - apcs-msm8916.c
>>     rework patch to use of_clk_parent_fill
>>
>>   - hfpll.c
>>     add relevant comments to the code
>>
>>   - qcs404.dtsi
>>     add voltage scaling support
>>
>> v4:
>>  - squash OPP definition and DVFS enablement in dts
>>    (patches 10 and 13 in previous version)
>>    
>>  - qcom-apcs-ipc-mailbox
>>    replace return condition for readability
>>    
>>  - answer one question on CLK_IGNORE_UNUSED in mailing list
>>
>> Jorge Ramirez-Ortiz, Niklas Cassel (13):
>>   clk: qcom: gcc: limit GPLL0_AO_OUT operating frequency
>>   mbox: qcom: add APCS child device for QCS404
>>   mbox: qcom: replace integer with valid macro
>>   dt-bindings: mailbox: qcom: Add clock-name optional property
>>   clk: qcom: apcs-msm8916: get parent clock names from DT
>>   clk: qcom: hfpll: get parent clock names from DT
>>   clk: qcom: hfpll: register as clock provider
>>   clk: qcom: hfpll: CLK_IGNORE_UNUSED
>>   arm64: dts: qcom: msm8916: Add the clocks for the APCS mux/divider
>>   arm64: dts: qcom: qcs404: Add HFPLL node
>>   arm64: dts: qcom: qcs404: Add the clocks for APCS mux/divider
>>   arm64: dts: qcom: qcs404: Add DVFS support
>>   arm64: defconfig: Enable HFPLL
>>
>>  .../mailbox/qcom,apcs-kpss-global.txt         | 24 +++++++++--
>>  arch/arm64/boot/dts/qcom/msm8916.dtsi         |  3 +-
>>  arch/arm64/boot/dts/qcom/qcs404.dtsi          | 43 +++++++++++++++++++
>>  arch/arm64/configs/defconfig                  |  1 +
>>  drivers/clk/qcom/apcs-msm8916.c               | 23 ++++++++--
>>  drivers/clk/qcom/clk-alpha-pll.c              |  8 ++++
>>  drivers/clk/qcom/clk-alpha-pll.h              |  1 +
>>  drivers/clk/qcom/gcc-qcs404.c                 |  2 +-
>>  drivers/clk/qcom/hfpll.c                      | 25 ++++++++++-
>>  drivers/mailbox/qcom-apcs-ipc-mailbox.c       | 11 +++--
>>  10 files changed, 128 insertions(+), 13 deletions(-)
>>
> 
> any feedback on this set?
> 
> TIA
> 

trying to ease the maintainers task, I have resent the series split in
three individual sets:

- device tree
- clk
- mbox

for full functionality obviously all of them are required

please let me know if there is anything else I can do.