linux-kernel - Re: [PATCH v1] drivers/tty/serial/8250: check the return value of clk_prepare

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Message-ID: <Yyg3KKDCLaQUb2P0@kroah.com>
Date:   Mon, 19 Sep 2022 11:32:24 +0200
From:   Greg KH <greg@...ah.com>
To:     Li Zhong <floridsleeves@...il.com>
Cc:     linux-kernel@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-serial@...r.kernel.org,
        etremblay@...tech-controls.com, l.sanfilippo@...bus.com,
        u.kleine-koenig@...gutronix.de, robert.hancock@...ian.com,
        ilpo.jarvinen@...ux.intel.com, matthias.bgg@...il.com,
        p.zabel@...gutronix.de, jirislaby@...nel.org
Subject: Re: [PATCH v1] drivers/tty/serial/8250: check the return value of
 clk_prepare_enable()

On Mon, Sep 19, 2022 at 01:54:55AM -0700, Li Zhong wrote:
> Check the return value of clk_prepare_enable() which could fail when
> cannot enable the clock.
> 
> Signed-off-by: Li Zhong <floridsleeves@...il.com>
> ---
>  drivers/tty/serial/8250/8250_of.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
> index 1b461fba15a3..23e9b9e8c940 100644
> --- a/drivers/tty/serial/8250/8250_of.c
> +++ b/drivers/tty/serial/8250/8250_of.c
> @@ -298,7 +298,8 @@ static int of_serial_resume(struct device *dev)
>  
>  	if (!uart_console(port) || console_suspend_enabled) {
>  		pm_runtime_get_sync(dev);
> -		clk_prepare_enable(info->clk);
> +		if (clk_prepare_enable(info->clk) < 0)
> +			dev_warn(dev, "can't enable clk.\n");

Again, you check but do nothing with the error :(