Re: [PATCH] usb: dwc3-exynos fix unspecified suspend clk error handling

From: Bartlomiej Zolnierkiewicz
Date: Tue Jan 10 2017 - 07:06:15 EST



Hi,

On Monday, January 09, 2017 07:21:31 PM Shuah Khan wrote:
> Fix dwc3_exynos_probe() to call clk_prepare_enable() only when suspend
> clock is specified. Call clk_disable_unprepare() from remove and probe
> error path only when susp_clk has been set from remove and probe error
> paths.

It is legal to call clk_prepare_enable() and clk_disable_unprepare()
for NULL clock. Also your patch changes susp_clk handling while
leaves axius_clk handling (which also can be NULL) untouched.

Do you actually see some runtime problem with the current code?

If not then the patch should probably be dropped.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

> Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/dwc3-exynos.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/usb/dwc3/dwc3-exynos.c b/drivers/usb/dwc3/dwc3-exynos.c
> index e27899b..f97a3d7 100644
> --- a/drivers/usb/dwc3/dwc3-exynos.c
> +++ b/drivers/usb/dwc3/dwc3-exynos.c
> @@ -131,8 +131,8 @@ static int dwc3_exynos_probe(struct platform_device *pdev)
> if (IS_ERR(exynos->susp_clk)) {
> dev_info(dev, "no suspend clk specified\n");
> exynos->susp_clk = NULL;
> - }
> - clk_prepare_enable(exynos->susp_clk);
> + } else
> + clk_prepare_enable(exynos->susp_clk);
>
> if (of_device_is_compatible(node, "samsung,exynos7-dwusb3")) {
> exynos->axius_clk = devm_clk_get(dev, "usbdrd30_axius_clk");
> @@ -196,7 +196,8 @@ static int dwc3_exynos_probe(struct platform_device *pdev)
> regulator_disable(exynos->vdd33);
> err2:
> clk_disable_unprepare(exynos->axius_clk);
> - clk_disable_unprepare(exynos->susp_clk);
> + if (exynos->susp_clk)
> + clk_disable_unprepare(exynos->susp_clk);
> clk_disable_unprepare(exynos->clk);
> return ret;
> }
> @@ -210,7 +211,8 @@ static int dwc3_exynos_remove(struct platform_device *pdev)
> platform_device_unregister(exynos->usb3_phy);
>
> clk_disable_unprepare(exynos->axius_clk);
> - clk_disable_unprepare(exynos->susp_clk);
> + if (exynos->susp_clk)
> + clk_disable_unprepare(exynos->susp_clk);
> clk_disable_unprepare(exynos->clk);
>
> regulator_disable(exynos->vdd33);