Re: [PATCH V2 07/15] cpufreq: mediatek: Add opp notification for SVS support

From: Kevin Hilman <khilman@baylibre.com>
To: Rex-BC Chen <rex-bc.chen@mediatek.com>,
	rafael@kernel.org, viresh.kumar@linaro.org, robh+dt@kernel.org,
	krzk+dt@kernel.org
Cc: matthias.bgg@gmail.com, jia-wei.chang@mediatek.com,
	roger.lu@mediatek.com, hsinyi@google.com,
	linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	Project_Global_Chrome_Upstream_Group@mediatek.com,
	"Andrew-sh.Cheng" <andrew-sh.cheng@mediatek.com>,
	Rex-BC Chen <rex-bc.chen@mediatek.com>
Subject: Re: [PATCH V2 07/15] cpufreq: mediatek: Add opp notification for SVS support
Date: Fri, 08 Apr 2022 13:29:10 -0700	[thread overview]
Message-ID: <7hsfqn5nft.fsf@baylibre.com> (raw)
In-Reply-To: <20220408045908.21671-8-rex-bc.chen@mediatek.com>

Rex-BC Chen <rex-bc.chen@mediatek.com> writes:

> From: "Andrew-sh.Cheng" <andrew-sh.cheng@mediatek.com>
>
> The Smart Voltage Scaling (SVS) is a hardware which calculates suitable
> SVS bank voltages to OPP voltage table.
>
> When the SVS is enabled, cpufreq should listen to opp notification and do
> proper actions when receiving events of disable and voltage adjustment.

So listenting for OPP notifications should be done only when SVS is enabled...

[...]

>  static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>  {
>  	struct device *cpu_dev;
> @@ -392,6 +455,17 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
>  	info->intermediate_voltage = dev_pm_opp_get_voltage(opp);
>  	dev_pm_opp_put(opp);
>  
> +	info->opp_cpu = cpu;
> +	info->opp_nb.notifier_call = mtk_cpufreq_opp_notifier;
> +	ret = dev_pm_opp_register_notifier(cpu_dev, &info->opp_nb);

...but here youlisten to OPP notifications unconditionally.  Seems there
should be a check whether SVS is enabled before deciding to register.

Kevin

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