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

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

[Wolfram Sang]

From: Wolfram Sang <wsa+renesas@sang-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@sang-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;
+	}
 
 	mutex_init(&lpc18xx_pwm->res_lock);
 	mutex_init(&lpc18xx_pwm->period_lock);
-- 
2.7.0

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

[Joachim Eastwood]

Hi Wolfram,

On 2 March 2016 at 23:57, Wolfram Sang <wsa@the-dreams.de> wrote:
> From: Wolfram Sang <wsa+renesas@sang-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@sang-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@gmail.com>

Thanks for fixing this.


regards,
Joachim Eastwood

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

[Thierry Reding]

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On Wed, Mar 02, 2016 at 11:57:09PM +0100, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-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@sang-engineering.com>
> ---
>  drivers/pwm/pwm-lpc18xx-sct.c | 5 +++++
>  1 file changed, 5 insertions(+)

Applied, thanks.

Thierry

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