linux-kernel - Re: [PATCH 3/4] rtc: s3c: use unified functions for enable/disable of clk

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Date:	Wed, 12 Aug 2015 09:10:06 +0900
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Joonyoung Shim <jy0922.shim@...sung.com>,
	rtc-linux@...glegroups.com
Cc:	linux-kernel@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
	a.zummo@...ertech.it, alexandre.belloni@...e-electrons.com,
	cw00.choi@...sung.com
Subject: Re: [PATCH 3/4] rtc: s3c: use unified functions for enable/disable of
 clk

On 11.08.2015 20:28, Joonyoung Shim wrote:
> The driver uses clk_prepare_enable()/clk_disable_unprepare() only in
> probe only, elsewhere, use the unified functions for enable/disable of
> clk, e.g. s3c_rtc_enable_clk() / s3c_rtc_disable_clk(), so it's better
> to use them for consistency of code.
> 
> Signed-off-by: Joonyoung Shim <jy0922.shim@...sung.com>
> ---
>  drivers/rtc/rtc-s3c.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)

First of all - the code is larger (9 insertions, 5 deletion) so I have
doubts if this is better.

Second - this is not equivalent change. The s3c_rtc_enable_clk/disable
calls grab spin lock which is not necessary in probe.

Best regards,
Krzysztof

> 
> diff --git a/drivers/rtc/rtc-s3c.c b/drivers/rtc/rtc-s3c.c
> index 44b2921..abe2a6d 100644
> --- a/drivers/rtc/rtc-s3c.c
> +++ b/drivers/rtc/rtc-s3c.c
> @@ -476,19 +476,21 @@ static int s3c_rtc_probe(struct platform_device *pdev)
>  		dev_err(&pdev->dev, "failed to find rtc clock\n");
>  		return PTR_ERR(info->rtc_clk);
>  	}
> -	clk_prepare_enable(info->rtc_clk);
> +	clk_prepare(info->rtc_clk);
>  
>  	if (info->data->needs_src_clk) {
>  		info->rtc_src_clk = devm_clk_get(&pdev->dev, "rtc_src");
>  		if (IS_ERR(info->rtc_src_clk)) {
>  			dev_err(&pdev->dev,
>  				"failed to find rtc source clock\n");
> -			clk_disable_unprepare(info->rtc_clk);
> +			clk_unprepare(info->rtc_clk);
>  			return PTR_ERR(info->rtc_src_clk);
>  		}
> -		clk_prepare_enable(info->rtc_src_clk);
> +		clk_prepare(info->rtc_src_clk);
>  	}
>  
> +	s3c_rtc_enable_clk(info);
> +
>  	/* check to see if everything is setup correctly */
>  	if (info->data->enable)
>  		info->data->enable(info);
> @@ -548,9 +550,11 @@ static int s3c_rtc_probe(struct platform_device *pdev)
>  	if (info->data->disable)
>  		info->data->disable(info);
>  
> +	s3c_rtc_disable_clk(info);
> +
>  	if (info->data->needs_src_clk)
> -		clk_disable_unprepare(info->rtc_src_clk);
> -	clk_disable_unprepare(info->rtc_clk);
> +		clk_unprepare(info->rtc_src_clk);
> +	clk_unprepare(info->rtc_clk);
>  
>  	return ret;
>  }
> 

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