linux-kernel - Re: [PATCH v2] pwm: pwm-lpc18xx-sct: test clock rate to avoid division by 0

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Date:	Thu, 3 Mar 2016 00:28:29 +0100
From:	Joachim Eastwood <manabian@...il.com>
To:	Wolfram Sang <wsa@...-dreams.de>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Thierry Reding <thierry.reding@...il.com>,
	linux-pwm@...r.kernel.org,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"Ariel D'Alessandro" <ariel@...guardiasur.com.ar>
Subject: Re: [PATCH v2] pwm: pwm-lpc18xx-sct: test clock rate to avoid
 division by 0

Hi Wolfram,

On 2 March 2016 at 23:57, Wolfram Sang <wsa@...-dreams.de> wrote:
> From: Wolfram Sang <wsa+renesas@...g-engineering.com>
>
> The clk API may return 0 on clk_get_rate, so we should check the result before
> using it as a divisor.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
> ---
>  drivers/pwm/pwm-lpc18xx-sct.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/pwm/pwm-lpc18xx-sct.c b/drivers/pwm/pwm-lpc18xx-sct.c
> index 9163085101bc94..9861fed4e67d04 100644
> --- a/drivers/pwm/pwm-lpc18xx-sct.c
> +++ b/drivers/pwm/pwm-lpc18xx-sct.c
> @@ -360,6 +360,11 @@ static int lpc18xx_pwm_probe(struct platform_device *pdev)
>         }
>
>         lpc18xx_pwm->clk_rate = clk_get_rate(lpc18xx_pwm->pwm_clk);
> +       if (!lpc18xx_pwm->clk_rate) {
> +               dev_err(&pdev->dev, "pwm clock has no frequency\n");
> +               ret = -EINVAL;
> +               goto disable_pwmclk;
> +       }

Acked-by: Joachim Eastwood <manabian@...il.com>

Thanks for fixing this.


regards,
Joachim Eastwood