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Message-ID: <b5033b2b-a39a-41d4-b47d-f120743a79bd@linaro.org>
Date:   Sat, 21 Oct 2023 19:04:54 +0200
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Subject: Re: [PATCH v5 5/9] clk: qcom: apss-ipq6018: ipq5332: add safe source
 switch for a53pll
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To:     Varadarajan Narayanan <quic_varada@quicinc.com>, agross@kernel.org,
        andersson@kernel.org, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
        mturquette@baylibre.com, sboyd@kernel.org, rafael@kernel.org,
        viresh.kumar@linaro.org, ilia.lin@kernel.org,
        sivaprak@codeaurora.org, quic_kathirav@quicinc.com,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
        linux-pm@vger.kernel.org
References: <cover.1697781921.git.quic_varada@quicinc.com>
 <49422d258d67d33a2547fbb7f4f6e72d489c2301.1697781921.git.quic_varada@quicinc.com>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <49422d258d67d33a2547fbb7f4f6e72d489c2301.1697781921.git.quic_varada@quicinc.com>
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On 10/20/23 08:19, Varadarajan Narayanan wrote:
> Stromer Plus PLL found on IPQ53xx doesn't support dynamic
> frequency scaling. To achieve the same, we need to park the APPS
> PLL source to GPLL0, re configure the PLL and then switch the
> source to APSS_PLL_EARLY.
> 
> To support this, register a clock notifier to get the PRE_RATE
> and POST_RATE notification. Change the APSS PLL source to GPLL0
> when PRE_RATE notification is received, then configure the PLL
> and then change back the source to APSS_PLL_EARLY.
> 
> Additionally, not all SKUs of IPQ53xx support scaling. Hence,
> do the above to the SKUs that support scaling.
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> Signed-off-by: Kathiravan T <quic_kathirav@quicinc.com>
> Signed-off-by: Varadarajan Narayanan <quic_varada@quicinc.com>
> ---
This looks good, however I'm not sure if registering the callback
only on SoCs that are supposed to rate-change isn't
overly-defensive. That said, I'm not particularly against it.

Acked-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad