linux-kernel - Re: [PATCH v7 2/2] cpufreq: qcom-hw: Add support for QCOM cpufreq HW driver

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Date:   Sun, 23 Sep 2018 15:05:05 +0530
From:   Taniya Das <tdas@...eaurora.org>
To:     Stephen Boyd <sboyd@...nel.org>, skannan@...eaurora.org
Cc:     Evan Green <evgreen@...gle.com>, rjw@...ysocki.net,
        Viresh Kumar <viresh.kumar@...aro.org>,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        Rajendra Nayak <rnayak@...eaurora.org>,
        anischal@...eaurora.org, devicetree@...r.kernel.org,
        robh@...nel.org, amit.kucheria@...aro.org
Subject: Re: [PATCH v7 2/2] cpufreq: qcom-hw: Add support for QCOM cpufreq HW
 driver

Hello Stephen,


On 8/24/2018 12:08 AM, Stephen Boyd wrote:
> Quoting Taniya Das (2018-08-08 03:15:26)
>>
>>
>> On 8/8/2018 11:52 AM, Stephen Boyd wrote:
>>>>
>>>> Binding describes hardware controllable by the OS. That's the reality.
>>>> Let's not add mandatory clock bindings for clocks that the OS can't do
>>>> anything about.
>>>>
>>>
>>> It seems that you believe clks should only be used to turn on/off and
>>> control rates. That is not the whole truth. Sometimes clks are there
>>> just to express the clk frequencies that are present in the design so
>>> that drivers can figure out what to do.
>>>
>>
>> Stephen,
>>
>> As this clock is not configurable by linux clock drivers and we really
>> do not care the parent src(as mentioned by Saravana) to generate the
>> 300MHz, would it be good to define a fixed rate clock so as to express
>> the HW connectivity & frequency?
>>
> 
> As a hack that works great, but why do we need to workaround problems by
> adding a fixed rate clk to DT for this PLL? The PLL is provided by GCC
> node so it should be connected to the GCC node.
> 

Please help with review the next patch series which would take the PLL 
phandle from DT.

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