Hi,
On 2/17/20 8:07 PM, H. Nikolaus Schaller wrote:
> Hi Chanwoo Choi,
>
>> Am 17.02.2020 um 11:15 schrieb Chanwoo Choi <cw00.choi@xxxxxxxxxxx>:
>>
>> Hi,
>>
>> On 2/17/20 5:55 PM, H. Nikolaus Schaller wrote:
>>> If the gpios are probed after this driver (e.g. if they
>>> come from an i2c expander) there is no need to print an
>>> error message.
>>>
>>> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
>>> ---
>>> drivers/extcon/extcon-palmas.c | 6 ++++--
>>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c
>>> index edc5016f46f1..9c6254c0531c 100644
>>> --- a/drivers/extcon/extcon-palmas.c
>>> +++ b/drivers/extcon/extcon-palmas.c
>>> @@ -206,14 +206,16 @@ static int palmas_usb_probe(struct platform_device *pdev)
>>> palmas_usb->id_gpiod = devm_gpiod_get_optional(&pdev->dev, "id",
>>> GPIOD_IN);
>>> if (IS_ERR(palmas_usb->id_gpiod)) {
>>> - dev_err(&pdev->dev, "failed to get id gpio\n");
>>> + if (PTR_ERR(palmas_usb->id_gpiod) != -EPROBE_DEFER)
>>> + dev_err(&pdev->dev, "failed to get id gpio\n");
>>> return PTR_ERR(palmas_usb->id_gpiod);
>>> }
How about editing it ? as following:
because following suggestion reduces the one checking behavior
when return value is -EPROBE_DEFER.
if (PTR_ERR(palmas_usb->id_gpiod) == -EPROBE_DEFER) {
return -EPROBE_DEFER;
} else if (IS_ERR(palmas_usb->id_gpiod)) {
dev_err(&pdev->dev, "failed to get id gpio\n");
return PTR_ERR(palmas_usb->id_gpiod);
}
>>>
>>> palmas_usb->vbus_gpiod = devm_gpiod_get_optional(&pdev->dev, "vbus",
>>> GPIOD_IN);
>>> if (IS_ERR(palmas_usb->vbus_gpiod)) {
>>> - dev_err(&pdev->dev, "failed to get vbus gpio\n");
>>> + if (PTR_ERR(palmas_usb->vbus_gpiod) != -EPROBE_DEFER)
>>> + dev_err(&pdev->dev, "failed to get vbus gpio\n");
ditto.
>>> return PTR_ERR(palmas_usb->vbus_gpiod);
>>> }
>>>
>>>
>>
>> Usually, gpio driver like pinctrl is very early probed
>> because almost device drivers should use gpio.
>> So, I have not any experience about this situation.
>> Do you meet this situation on any h/w board?
>
> Yes, I have experienced that sometimes on omap5+palmas based boards.
>
> It seems to be this:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/omap5-board-common.dtsi?h=v5.6-rc2#n384
>
> The extcon_usb3 can potentially match this extcon-palmas driver at
> a moment where the palmas_gpio it is referring to has not yet been
> successfully probed. Then the palmas_gpio would return -EPROBE_DEFER.
>
> AFAIK there is no guarantee for a specific sequence of drivers
> being probed and it is pure luck that in most cases the gpios
> are already probed.
Thanks for explaining the example.
--
Best Regards,
Chanwoo Choi
Samsung Electronics
