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From:   Alexander Stein <alexander.stein@ew.tq-group.com>
To:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc:     shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de,
        festevam@gmail.com, linux-imx@nxp.com, xiaolei.wang@windriver.com,
        l.stach@pengutronix.de, Yang Yingliang <yangyingliang@huawei.com>
Subject: Re: [PATCH] soc: imx8m: fix wrong return value check of of_clk_get_by_name()
Date:   Wed, 04 Jan 2023 08:50:47 +0100
Message-ID: <1882509.eGJsNajkDb@steina-w>
Organization: TQ-Systems GmbH
In-Reply-To: <20230104064136.1695102-1-yangyingliang@huawei.com>
References: <20230104064136.1695102-1-yangyingliang@huawei.com>
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Hi,

Am Mittwoch, 4. Januar 2023, 07:41:36 CET schrieb Yang Yingliang:
> of_clk_get_by_name() never returns NULL pointer, it will return
> ERR_PTR() when it fails, so replace the check with IS_ERR().
> 
> Fixes: 836fb30949d9 ("soc: imx8m: Enable OCOTP clock before reading the
> register") Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>  drivers/soc/imx/soc-imx8m.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/imx/soc-imx8m.c b/drivers/soc/imx/soc-imx8m.c
> index 28144c699b0c..32ed9dc88e45 100644
> --- a/drivers/soc/imx/soc-imx8m.c
> +++ b/drivers/soc/imx/soc-imx8m.c
> @@ -66,8 +66,8 @@ static u32 __init imx8mq_soc_revision(void)
>  	ocotp_base = of_iomap(np, 0);
>  	WARN_ON(!ocotp_base);
>  	clk = of_clk_get_by_name(np, NULL);
> -	if (!clk) {
> -		WARN_ON(!clk);
> +	if (IS_ERR(clk)) {

Nice catch. But wouldn't
> if (WARN_ON(IS_ERR(clk)))
be even better instead of doing the check twice?

Best regards,
Alexander

> +		WARN_ON(IS_ERR(clk));
>  		return 0;
>  	}