linux-kernel - Re: [PATCH] rtc: jz4740: Use devm_clk_get

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Message-Id: <UC07HR.REF39SO0Y5PG2@crapouillou.net>
Date:   Thu, 25 Aug 2022 23:41:18 +0100
From:   Paul Cercueil <paul@...pouillou.net>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        linux-mips@...r.kernel.org, linux-rtc@...r.kernel.org
Subject: Re: [PATCH] rtc: jz4740: Use devm_clk_get_enabled() helper

Hi Christophe,

Le mer., août 24 2022 at 10:42:29 +0200, Christophe JAILLET 
<christophe.jaillet@...adoo.fr> a écrit :
> The devm_clk_get_enabled() helper:
>    - calls devm_clk_get()
>    - calls clk_prepare_enable() and registers what is needed in order 
> to
>      call clk_disable_unprepare() when needed, as a managed resource.
> 
> This simplifies the code, the error handling paths and avoid the need 
> of
> a dedicated function used with devm_add_action_or_reset().
> 
> 
> As a side effect, some error messages are not logged anymore, so also 
> use
> dev_err_probe() instead of dev_err() in case of error.
> At least the error code will be logged (and -EPROBE_DEFER will be 
> filtered)
> 
> Based on my test with allyesconfig, this reduces the .o size from:
>    text	   data	    bss	    dec	    hex	filename
>    9025	   2488	    128	  11641	   2d79	drivers/rtc/rtc-jz4740.o
> down to:
>    8267	   2080	    128	  10475	   28eb	drivers/rtc/rtc-jz4740.o
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>

Acked-by: Paul Cercueil <paul@...pouillou.net>

> ---
> devm_clk_get_enabled() is new and is part of 6.0-rc1
> 
> Some recent changed use "rtc: ingenic". This looks odd to me, so turn 
> back
> to "rtc: jz4740"

Yes, the driver basically supports everything Ingenic now, so I 
generally write "rtc: ingenic:", but "rtc: jz4740:" is absolutely fine.

Cheers,
-Paul

> ---
>  drivers/rtc/rtc-jz4740.c | 25 +++----------------------
>  1 file changed, 3 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-jz4740.c b/drivers/rtc/rtc-jz4740.c
> index 6e51df72fd65..c383719292c7 100644
> --- a/drivers/rtc/rtc-jz4740.c
> +++ b/drivers/rtc/rtc-jz4740.c
> @@ -257,11 +257,6 @@ static void jz4740_rtc_power_off(void)
>  	kernel_halt();
>  }
> 
> -static void jz4740_rtc_clk_disable(void *data)
> -{
> -	clk_disable_unprepare(data);
> -}
> -
>  static const struct of_device_id jz4740_rtc_of_match[] = {
>  	{ .compatible = "ingenic,jz4740-rtc", .data = (void *)ID_JZ4740 },
>  	{ .compatible = "ingenic,jz4760-rtc", .data = (void *)ID_JZ4760 },
> @@ -329,23 +324,9 @@ static int jz4740_rtc_probe(struct 
> platform_device *pdev)
>  	if (IS_ERR(rtc->base))
>  		return PTR_ERR(rtc->base);
> 
> -	clk = devm_clk_get(dev, "rtc");
> -	if (IS_ERR(clk)) {
> -		dev_err(dev, "Failed to get RTC clock\n");
> -		return PTR_ERR(clk);
> -	}
> -
> -	ret = clk_prepare_enable(clk);
> -	if (ret) {
> -		dev_err(dev, "Failed to enable clock\n");
> -		return ret;
> -	}
> -
> -	ret = devm_add_action_or_reset(dev, jz4740_rtc_clk_disable, clk);
> -	if (ret) {
> -		dev_err(dev, "Failed to register devm action\n");
> -		return ret;
> -	}
> +	clk = devm_clk_get_enabled(dev, "rtc");
> +	if (IS_ERR(clk))
> +		return dev_err_probe(dev, PTR_ERR(clk), "Failed to get RTC 
> clock\n");
> 
>  	spin_lock_init(&rtc->lock);
> 
> --
> 2.34.1
>