On 01/10/2017 05:05 AM, Bartlomiej Zolnierkiewicz wrote:
>
> 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
Hi Bartlomiej,
I am seeing the "no suspend clk specified" message in dmesg.
After that it sets the exynos->susp_clk = NULL and starts
calling clk_prepare_enable(exynos->susp_clk);
That can't be good. If you see the logic right above this
one for exynos->clk, it returns error and fails the probe.
This this case it doesn't, but tries to use null susp_clk.
I believe this patch is necessary.
thanks,
-- Shuah
>
>> 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);
>
--
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