linux-kernel - Re: [PATCH] PM / devfreq: mtk-cci: refactor error handling of probe and remove

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Message-ID: <6439bf4e-979e-889e-c97d-e7b1dd94b4f1@collabora.com>
Date:   Wed, 3 May 2023 13:40:56 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     "jia-wei.chang" <jia-wei.chang@...iatek.com>,
        MyungJoo Ham <myungjoo.ham@...sung.com>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Johnson Wang <johnson.wang@...iatek.com>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com,
        hsinyi@...gle.com
Subject: Re: [PATCH] PM / devfreq: mtk-cci: refactor error handling of probe
 and remove

Il 03/05/23 11:27, jia-wei.chang ha scritto:
> From: Jia-Wei Chang <jia-wei.chang@...iatek.com>
> 
> To refactor the regulator/clk handlers so it can follow the way of "Free
> the Last Thing Style".
> 
> Signed-off-by: Jia-Wei Chang <jia-wei.chang@...iatek.com>
> Fixes: 86d231b1db1b ("PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver")
> ---
>   drivers/devfreq/mtk-cci-devfreq.c | 47 ++++++++++++++++++-------------
>   1 file changed, 28 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/devfreq/mtk-cci-devfreq.c b/drivers/devfreq/mtk-cci-devfreq.c
> index e5458ada5197..d2f743774147 100644
> --- a/drivers/devfreq/mtk-cci-devfreq.c
> +++ b/drivers/devfreq/mtk-cci-devfreq.c
> @@ -294,14 +294,14 @@ static int mtk_ccifreq_probe(struct platform_device *pdev)
>   	if (IS_ERR(drv->sram_reg)) {
>   		ret = PTR_ERR(drv->sram_reg);
>   		if (ret == -EPROBE_DEFER)
> -			goto out_free_resources;
> +			goto out_disable_proc_reg;
>   
>   		drv->sram_reg = NULL;
>   	} else {
>   		ret = regulator_enable(drv->sram_reg);
>   		if (ret) {
>   			dev_err(dev, "failed to enable sram regulator\n");
> -			goto out_free_resources;
> +			goto out_disable_proc_reg;
>   		}
>   	}
>   
> @@ -316,12 +316,16 @@ static int mtk_ccifreq_probe(struct platform_device *pdev)
>   
>   	ret = clk_prepare_enable(drv->cci_clk);
>   	if (ret)
> -		goto out_free_resources;
> +		goto out_disable_sram_reg;
> +
> +	ret = clk_prepare_enable(drv->inter_clk);

Adding a clk_prepare_enable() call for a clock must be done in a separate commit.
Besides, there shouldn't be any need to do that, as when you call clk_set_parent()
(done in mtk_ccifreq_target()) on a clock that has flag CLK_OPS_PARENT_ENABLE, the
clk core will automatically call clk_core_prepare_enable() on the new parent.

If you're facing a bug for which the parent is not getting enabled, the solution
is to add CLK_OPS_PARENT_ENABLE to the interested clock.

Regards,
Angelo