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Date:   Fri, 18 Dec 2020 15:32:32 +0100
From:   Fabrice Gasnier <fabrice.gasnier@...s.st.com>
To:     Xu Wang <vulab@...as.ac.cn>, <jic23@...nel.org>, <lars@...afoo.de>,
        <pmeerw@...erw.net>, <mcoquelin.stm32@...il.com>,
        <alexandre.torgue@...com>, <krzk@...nel.org>,
        <andy.shevchenko@...il.com>, <olivier.moysan@...com>,
        <etienne.carriere@...com>, <alexandru.ardelean@...log.com>,
        <peter.ujfalusi@...com>, <linux-iio@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] iio: adc: stm32-adc: Remove redundant null check before
 clk_prepare_enable/clk_disable_unprepare

On 12/18/20 10:35 AM, Xu Wang wrote:
> Because clk_prepare_enable() and clk_disable_unprepare() already checked
> NULL clock parameter, so the additional checks are unnecessary, just
> remove them.
> 
> Signed-off-by: Xu Wang <vulab@...as.ac.cn>
> ---
>  drivers/iio/adc/stm32-adc-core.c | 29 +++++++++++------------------
>  drivers/iio/adc/stm32-adc.c      | 14 +++++---------
>  2 files changed, 16 insertions(+), 27 deletions(-)

Hi Xu,

Acked-by: Fabrice Gasnier <fabrice.gasnier@...s.st.com>

Thanks for your patch,
Best Regards,
Fabrice

> 
> diff --git a/drivers/iio/adc/stm32-adc-core.c b/drivers/iio/adc/stm32-adc-core.c
> index 9d1ad6e38e85..c088cb990193 100644
> --- a/drivers/iio/adc/stm32-adc-core.c
> +++ b/drivers/iio/adc/stm32-adc-core.c
> @@ -535,20 +535,16 @@ static int stm32_adc_core_hw_start(struct device *dev)
>  		goto err_switches_dis;
>  	}
>  
> -	if (priv->bclk) {
> -		ret = clk_prepare_enable(priv->bclk);
> -		if (ret < 0) {
> -			dev_err(dev, "bus clk enable failed\n");
> -			goto err_regulator_disable;
> -		}
> +	ret = clk_prepare_enable(priv->bclk);
> +	if (ret < 0) {
> +		dev_err(dev, "bus clk enable failed\n");
> +		goto err_regulator_disable;
>  	}
>  
> -	if (priv->aclk) {
> -		ret = clk_prepare_enable(priv->aclk);
> -		if (ret < 0) {
> -			dev_err(dev, "adc clk enable failed\n");
> -			goto err_bclk_disable;
> -		}
> +	ret = clk_prepare_enable(priv->aclk);
> +	if (ret < 0) {
> +		dev_err(dev, "adc clk enable failed\n");
> +		goto err_bclk_disable;
>  	}
>  
>  	writel_relaxed(priv->ccr_bak, priv->common.base + priv->cfg->regs->ccr);
> @@ -556,8 +552,7 @@ static int stm32_adc_core_hw_start(struct device *dev)
>  	return 0;
>  
>  err_bclk_disable:
> -	if (priv->bclk)
> -		clk_disable_unprepare(priv->bclk);
> +	clk_disable_unprepare(priv->bclk);
>  err_regulator_disable:
>  	regulator_disable(priv->vref);
>  err_switches_dis:
> @@ -575,10 +570,8 @@ static void stm32_adc_core_hw_stop(struct device *dev)
>  
>  	/* Backup CCR that may be lost (depends on power state to achieve) */
>  	priv->ccr_bak = readl_relaxed(priv->common.base + priv->cfg->regs->ccr);
> -	if (priv->aclk)
> -		clk_disable_unprepare(priv->aclk);
> -	if (priv->bclk)
> -		clk_disable_unprepare(priv->bclk);
> +	clk_disable_unprepare(priv->aclk);
> +	clk_disable_unprepare(priv->bclk);
>  	regulator_disable(priv->vref);
>  	stm32_adc_core_switches_supply_dis(priv);
>  	regulator_disable(priv->vdda);
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index c067c994dae2..f7c53cea509a 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -546,8 +546,7 @@ static int stm32_adc_hw_stop(struct device *dev)
>  	if (adc->cfg->unprepare)
>  		adc->cfg->unprepare(indio_dev);
>  
> -	if (adc->clk)
> -		clk_disable_unprepare(adc->clk);
> +	clk_disable_unprepare(adc->clk);
>  
>  	return 0;
>  }
> @@ -558,11 +557,9 @@ static int stm32_adc_hw_start(struct device *dev)
>  	struct stm32_adc *adc = iio_priv(indio_dev);
>  	int ret;
>  
> -	if (adc->clk) {
> -		ret = clk_prepare_enable(adc->clk);
> -		if (ret)
> -			return ret;
> -	}
> +	ret = clk_prepare_enable(adc->clk);
> +	if (ret)
> +		return ret;
>  
>  	stm32_adc_set_res(adc);
>  
> @@ -575,8 +572,7 @@ static int stm32_adc_hw_start(struct device *dev)
>  	return 0;
>  
>  err_clk_dis:
> -	if (adc->clk)
> -		clk_disable_unprepare(adc->clk);
> +	clk_disable_unprepare(adc->clk);
>  
>  	return ret;
>  }
> 

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