linux-kernel - Re: [PATCH] clk: qcom: gcc-ipq6018: add QUP6 I2C clock

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Message-ID: <b4ce1fdf-0a05-479d-90f8-3a2a2e40b07f@quicinc.com>
Date:   Fri, 20 Oct 2023 12:10:32 +0530
From:   Kathiravan Thirumoorthy <quic_kathirav@...cinc.com>
To:     Robert Marko <robimarko@...il.com>
CC:     Konrad Dybcio <konrad.dybcio@...aro.org>, <agross@...nel.org>,
        <andersson@...nel.org>, <mturquette@...libre.com>,
        <sboyd@...nel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-clk@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] clk: qcom: gcc-ipq6018: add QUP6 I2C clock


On 10/19/2023 7:53 PM, Robert Marko wrote:
> On Thu, 19 Oct 2023 at 08:46, Kathiravan Thirumoorthy
> <quic_kathirav@...cinc.com> wrote:
>>
>> On 10/19/2023 1:59 AM, Konrad Dybcio wrote:
>>>
>>> On 10/15/23 18:20, Robert Marko wrote:
>>>> QUP6 I2C clock is listed in the dt bindings but it was never included in
>>>> the GCC driver.
>>>> So lets add support for it, its intentionally marked to never be
>>>> disabled
>>>> as its somehow affecting DVFS and if disabled it sometimes crashes the
>>>> board.
>>>>
>>>> Signed-off-by: Robert Marko <robimarko@...il.com>
>>>> ---
>>> Bjorn, would you be able to get an idea of what could be sitting
>>> on that bus?
>>>
>>> Or maybe the IPQ folks could know?
>>>
>> Konrad / Robert,
>>
>> Similar to IPQ9574, RPM needs this clock to communicate with PMIC over
>> I2C interface. Discussion happened here[1] is pretty much applicable to
>> IPQ6018 as well. Based on previous experience, we may need to document
>> the reason for CLK_IGNORE_UNUSED in driver as well. Nevertheless,
>>
>> Reviewed-by: Kathiravan Thirumoorthy <quic_kathirav@...cinc.com>
> Thanks for the explanation, it makes sense as I used to control the
> MP5496 directly
> via I2C.
>
> Is it possible to disable RPM so it doesn't conflict and just use the
> full MP5496 driver instead?
> I find the RPM quite limiting as there is no way to actually retrieve
> the current-voltage.


Robert, checked with the team and currently we don't have any option to 
disable the RPM as such.


>
> Regards,
> Robert
>> [1]
>> https://lore.kernel.org/linux-arm-msm/2852fc37-284f-6534-f163-45b37b153db1@quicinc.com/
>>
>>
>>> Konrad