linux-kernel - Re: [PATCH v4] PM / devfreq: exynos: Use Use devm_clk_get

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Message-ID: <d2943958-ac80-4158-8e7c-b5493ab713f8@wanadoo.fr>
Date: Thu, 9 May 2024 22:04:57 +0200
From: Christophe JAILLET <christophe.jaillet@...adoo.fr>
To: Anand Moon <linux.amoon@...il.com>, Chanwoo Choi <cw00.choi@...sung.com>,
 MyungJoo Ham <myungjoo.ham@...sung.com>,
 Kyungmin Park <kyungmin.park@...sung.com>,
 Krzysztof Kozlowski <krzk@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>
Cc: linux-pm@...r.kernel.org, linux-samsung-soc@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4] PM / devfreq: exynos: Use Use devm_clk_get_enabled()
 helpers

Le 09/05/2024 à 08:47, Anand Moon a écrit :
> The devm_clk_get_enabled() helpers:
>      - call devm_clk_get()
>      - call clk_prepare_enable() and register what is needed in order to
>       call clk_disable_unprepare() when needed, as a managed resource.
> 
> This simplifies the code and avoids the calls to clk_disable_unprepare().
> 
> While at it, use dev_err_probe consistently, and use its return value
> to return the error code.
> 
> Signed-off-by: Anand Moon <linux.amoon@...il.com>
> ---
> V4 - wrap up the error messagee within 80 char
> v3 - No change
> v2 - No change
> ---
>   drivers/devfreq/exynos-bus.c | 22 +++++-----------------
>   1 file changed, 5 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> index 00118580905a..7d06c476d8e9 100644
> --- a/drivers/devfreq/exynos-bus.c
> +++ b/drivers/devfreq/exynos-bus.c
> @@ -160,7 +160,6 @@ static void exynos_bus_exit(struct device *dev)
>   	platform_device_unregister(bus->icc_pdev);
>   
>   	dev_pm_opp_of_remove_table(dev);
> -	clk_disable_unprepare(bus->clk);
>   	dev_pm_opp_put_regulators(bus->opp_token);
>   }
>   
> @@ -171,7 +170,6 @@ static void exynos_bus_passive_exit(struct device *dev)
>   	platform_device_unregister(bus->icc_pdev);
>   
>   	dev_pm_opp_of_remove_table(dev);
> -	clk_disable_unprepare(bus->clk);
>   }
>   
>   static int exynos_bus_parent_parse_of(struct device_node *np,
> @@ -247,23 +245,16 @@ static int exynos_bus_parse_of(struct device_node *np,
>   	int ret;
>   
>   	/* Get the clock to provide each bus with source clock */
> -	bus->clk = devm_clk_get(dev, "bus");
> -	if (IS_ERR(bus->clk)) {
> -		dev_err(dev, "failed to get bus clock\n");
> -		return PTR_ERR(bus->clk);
> -	}
> -
> -	ret = clk_prepare_enable(bus->clk);
> -	if (ret < 0) {
> -		dev_err(dev, "failed to get enable clock\n");
> -		return ret;
> -	}
> +	bus->clk = devm_clk_get_enabled(dev, "bus");
> +	if (IS_ERR(bus->clk))
> +		return dev_err_probe(dev, PTR_ERR(bus->clk),
> +				"failed to get bus clock\n");
>   
>   	/* Get the freq and voltage from OPP table to scale the bus freq */
>   	ret = dev_pm_opp_of_add_table(dev);
>   	if (ret < 0) {
>   		dev_err(dev, "failed to get OPP table\n");
> -		goto err_clk;
> +		return ret;
>   	}
>   
>   	rate = clk_get_rate(bus->clk);
> @@ -281,8 +272,6 @@ static int exynos_bus_parse_of(struct device_node *np,
>   
>   err_opp:
>   	dev_pm_opp_of_remove_table(dev);
> -err_clk:
> -	clk_disable_unprepare(bus->clk);
>   
>   	return ret;
>   }
> @@ -453,7 +442,6 @@ static int exynos_bus_probe(struct platform_device *pdev)
>   
>   err:
>   	dev_pm_opp_of_remove_table(dev);
> -	clk_disable_unprepare(bus->clk);
>   err_reg:
>   	dev_pm_opp_put_regulators(bus->opp_token);
>   

Hi,

if the patch is correct, I think that clk in struct exynos_bus can be 
easily be removed as well.

CJ