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

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Date:   Fri, 8 Apr 2022 15:36:53 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Rex-BC Chen <rex-bc.chen@...iatek.com>, rafael@...nel.org,
        viresh.kumar@...aro.org, robh+dt@...nel.org, krzk+dt@...nel.org
Cc:     matthias.bgg@...il.com, jia-wei.chang@...iatek.com,
        roger.lu@...iatek.com, hsinyi@...gle.com, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com,
        "Andrew-sh.Cheng" <andrew-sh.cheng@...iatek.com>
Subject: Re: [PATCH V2 07/15] cpufreq: mediatek: Add opp notification for SVS
 support

Il 08/04/22 06:59, Rex-BC Chen ha scritto:
> From: "Andrew-sh.Cheng" <andrew-sh.cheng@...iatek.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.
> 
> Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@...iatek.com>
> Signed-off-by: Jia-Wei Chang <jia-wei.chang@...iatek.com>
> Signed-off-by: Rex-BC Chen <rex-bc.chen@...iatek.com>
> ---
>   drivers/cpufreq/mediatek-cpufreq.c | 90 +++++++++++++++++++++++++++---
>   1 file changed, 82 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index 472f4de29e5f..1369da62780a 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c

..snip..

> +
>   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);

You are registering this notifier, but never unregistering it.
Please unregister it in error conditions and also upon runtime removal of the
mediatek-cpufreq module.

-> dev_pm_opp_unregister_notifier()

Regards,
Angelo

> +	if (ret) {
> +		dev_warn(cpu_dev, "cpu%d: failed to register opp notifier\n", cpu);
> +		goto out_disable_inter_clock;
> +	}
> +
> +	mutex_init(&info->reg_lock);
> +	info->opp_freq = clk_get_rate(info->cpu_clk);
> +
>   	/*
>   	 * If SRAM regulator is present, software "voltage tracking" is needed
>   	 * for this CPU power domain.