[PATCH] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER

[PATCH] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER

[H. Nikolaus Schaller]

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@goldelico.com>
---
 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);
 	}
 
 	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");
 		return PTR_ERR(palmas_usb->vbus_gpiod);
 	}
 
-- 
2.23.0

Re: [PATCH] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER

[Chanwoo Choi]

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@goldelico.com>
> ---
>  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);
>  	}
>  
>  	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");
>  		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?

-- 
Best Regards,
Chanwoo Choi
Samsung Electronics

Re: [PATCH] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER

[H. Nikolaus Schaller]

Hi Chanwoo Choi,

> Am 17.02.2020 um 11:15 schrieb Chanwoo Choi <cw00.choi@samsung.com>:
> 
> 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@goldelico.com>
>> ---
>> 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);
>> 	}
>> 
>> 	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");
>> 		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.

BR and thanks,
Nikolaus Schaller

Re: [PATCH] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER

[Chanwoo Choi]

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@samsung.com>:
>>
>> 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@goldelico.com>
>>> ---
>>> 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

Re: [PATCH] extcon: palmas: hide error messages if gpio returns -EPROBE_DEFER

[H. Nikolaus Schaller]

Hi,

> Am 17.02.2020 um 12:24 schrieb Chanwoo Choi <cw00.choi@samsung.com>:
> 
> 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@samsung.com>:
>>> 
>>> 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@goldelico.com>
>>>> ---
>>>> 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);
> 	}

Yes, looks indeed to be valid (some discussion around
is here: https://lore.kernel.org/patchwork/patch/999602/ ).

So I'll send an update asap.

> 
>>>> 
>>>> 	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.

BR and thanks,
Nikolaus Schaller