linux-kernel - Re: [PATCH V8 7/8] devfreq: mediatek: cci devfreq register opp notification for SVS support

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Date:   Thu, 25 Mar 2021 17:11:14 +0900
From:   Chanwoo Choi <cw00.choi@...sung.com>
To:     "Andrew-sh.Cheng" <andrew-sh.cheng@...iatek.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Viresh Kumar <viresh.kumar@...aro.org>,
        Nishanth Menon <nm@...com>, Stephen Boyd <sboyd@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        srv_heupstream@...iatek.com
Subject: Re: [PATCH V8 7/8] devfreq: mediatek: cci devfreq register opp
 notification for SVS support

Hi,

I think that you can squash this patch to patch4.

On 3/23/21 8:34 PM, Andrew-sh.Cheng wrote:
> From: "Andrew-sh.Cheng" <andrew-sh.cheng@...iatek.com>
> 
> SVS will change the voltage of opp item.

What it the full name of SVS?

> CCI devfreq need to react to change frequency.
> 
> Signed-off-by: Andrew-sh.Cheng <andrew-sh.cheng@...iatek.com>
> ---
>  drivers/devfreq/mt8183-cci-devfreq.c | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/drivers/devfreq/mt8183-cci-devfreq.c b/drivers/devfreq/mt8183-cci-devfreq.c
> index 018543db7bae..6942a48f3f4f 100644
> --- a/drivers/devfreq/mt8183-cci-devfreq.c
> +++ b/drivers/devfreq/mt8183-cci-devfreq.c
> @@ -21,6 +21,7 @@ struct cci_devfreq {
>  	struct clk *cci_clk;
>  	int old_vproc;
>  	unsigned long old_freq;
> +	struct notifier_block opp_nb;
>  };
>  
>  static int mtk_cci_set_voltage(struct cci_devfreq *cci_df, int vproc)
> @@ -89,6 +90,26 @@ static int mtk_cci_devfreq_target(struct device *dev, unsigned long *freq,
>  	return 0;
>  }
>  
> +static int ccidevfreq_opp_notifier(struct notifier_block *nb,

I think that you better to change the function name as following:
ccidevfreq_opp_notifier -> mtk_cci_devfreq_opp_notifier

> +				   unsigned long event, void *data)
> +{
> +	struct dev_pm_opp *opp = data;
> +	struct cci_devfreq *cci_df = container_of(nb, struct cci_devfreq,
> +						  opp_nb);
> +	unsigned long	freq, volt;
> +
> +	if (event == OPP_EVENT_ADJUST_VOLTAGE) {
> +		freq = dev_pm_opp_get_freq(opp);
> +		/* current opp item is changed */
> +		if (freq == cci_df->old_freq) {
> +			volt = dev_pm_opp_get_voltage(opp);
> +			mtk_cci_set_voltage(cci_df, volt);
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static struct devfreq_dev_profile cci_devfreq_profile = {
>  	.target = mtk_cci_devfreq_target,
>  };
> @@ -98,12 +119,15 @@ static int mtk_cci_devfreq_probe(struct platform_device *pdev)
>  	struct device *cci_dev = &pdev->dev;
>  	struct cci_devfreq *cci_df;
>  	struct devfreq_passive_data *passive_data;
> +	struct notifier_block *opp_nb;
>  	int ret;
>  
>  	cci_df = devm_kzalloc(cci_dev, sizeof(*cci_df), GFP_KERNEL);
>  	if (!cci_df)
>  		return -ENOMEM;
>  
> +	opp_nb = &cci_df->opp_nb;

Just move this code at the neighborhood of 'opp_nb->notifier_call' init code.

> +
>  	cci_df->cci_clk = devm_clk_get(cci_dev, "cci_clock");
>  	ret = PTR_ERR_OR_ZERO(cci_df->cci_clk);
>  	if (ret) {
> @@ -152,6 +176,9 @@ static int mtk_cci_devfreq_probe(struct platform_device *pdev)
>  		goto err_opp;
>  	}
>  
> +	opp_nb->notifier_call = ccidevfreq_opp_notifier;
> +	dev_pm_opp_register_notifier(cci_dev, opp_nb);

Need to check whether return value is valid or not.

> +
>  	return 0;
>  
>  err_opp:
> 


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics