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SubjectRE: [PATCH] usb: cdns3: platform_get_irq_byname_optional instead platform_get_irq_byname
Date
Roger,
>
>Pawel,
>
>On 02/10/2020 12:08, Pawel Laszczak wrote:
>> Roger,
>>
>>>
>>> On 30/09/2020 09:57, Pawel Laszczak wrote:
>>>> To avoid duplicate error information patch replaces platform_get_irq_byname
>>>> into platform_get_irq_byname_optional.
>>>
>>> What is duplicate error information?
>>
>> The function platform_get_irq_byname print:
>> " dev_err(&dev->dev, "IRQ %s not found\n", name);" if error occurred.
>>
>> In core.c we have the another error message below invoking this function.
>> e.g
>> if (cdns->dev_irq < 0)
>> dev_err(dev, "couldn't get peripheral irq\n");
>>
>> So, it's looks like one dev_err is redundant.
>
>If we want all 3 IRQs to be valid irrespective of dr_mode then we should
>use platform_get_irq_byname() and error out in probe if (ret < 0 && ret != -EPROBE_DEFER).
>
>We can get rid of the irq check and duplicate error message in other places.

To be sure we understand each other correctly.

Are You suggesting to leave the platform_get_irq_byname()
and rid of from core.c the following lines :

if (cdns->dev_irq < 0)
dev_err(dev, "couldn't get peripheral irq\n");

and

dev_err(dev, "couldn't get otg irq\n");
?

A word of explanation why this patch has been sent.
During reviewing the cdnsp driver Chunfeng Yun add such comment:

"
> + cdns->dev_irq = platform_get_irq_byname(pdev, "peripheral");
> + if (cdns->dev_irq == -EPROBE_DEFER)
> + return cdns->dev_irq;
> +
> + if (cdns->dev_irq < 0)
> + dev_err(dev, "couldn't get peripheral irq\n");
Use platform_get_irq_byname_optional? otherwise no need print this log,
platform_get_irq_byname() will print it.
"

In this patch I've chosen the platform_get_irq_byname_optional because both
function do the same but the error message from core.c tell us little more then
generic message from platform_get_irq_byname.

Cheers
Pawel Laszczak

>
>cheers,
>-roger
>
>>
>>>
>>>>
>>>> A change was suggested during reviewing CDNSP driver by Chunfeng Yun.
>>>>
>>>> Signed-off-by: Pawel Laszczak <pawell@cadence.com>
>>>> ---
>>>> drivers/usb/cdns3/core.c | 4 ++--
>>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/usb/cdns3/core.c b/drivers/usb/cdns3/core.c
>>>> index a0f73d4711ae..a3f6dc44cf3a 100644
>>>> --- a/drivers/usb/cdns3/core.c
>>>> +++ b/drivers/usb/cdns3/core.c
>>>> @@ -465,7 +465,7 @@ static int cdns3_probe(struct platform_device *pdev)
>>>>
>>>> cdns->xhci_res[1] = *res;
>>>>
>>>> - cdns->dev_irq = platform_get_irq_byname(pdev, "peripheral");
>>>> + cdns->dev_irq = platform_get_irq_byname_optional(pdev, "peripheral");
>>>
>>> As per DT binding document, these are mandatory properties
>>
>> I think that name platform_get_irq_byname_optional is little confusing.
>> Function descriptions show that both are almost identical:
>> /**
>> * platform_get_irq_byname_optional - get an optional IRQ for a device by name
>> * @dev: platform device
>> * @name: IRQ name
>> *
>> * Get an optional IRQ by name like platform_get_irq_byname(). Except that it
>> * does not print an error message if an IRQ can not be obtained.
>> *
>> * Return: non-zero IRQ number on success, negative error number on failure.
>> */
>>
>>>
>>> - interrupts: Interrupts used by cdns3 controller:
>>> "host" - interrupt used by XHCI driver.
>>> "peripheral" - interrupt used by device driver
>>> "otg" - interrupt used by DRD/OTG part of driver
>>>
>>> for dr_mode == "otg" -> all 3 are mandatory.
>>> for dr_mode == "host" -> "otg" and "peripheral" IRQs are not required.
>>> for dr_mode == "periphearal" -> "otg" and "host" IRQs are not required.
>>>
>>>> if (cdns->dev_irq == -EPROBE_DEFER)
>>>> return cdns->dev_irq;
>>>>
>>>> @@ -477,7 +477,7 @@ static int cdns3_probe(struct platform_device *pdev)
>>>> return PTR_ERR(regs);
>>>> cdns->dev_regs = regs;
>>>>
>>>> - cdns->otg_irq = platform_get_irq_byname(pdev, "otg");
>>>> + cdns->otg_irq = platform_get_irq_byname_optional(pdev, "otg");
>>>> if (cdns->otg_irq == -EPROBE_DEFER)
>>>> return cdns->otg_irq;
>>>>
>>>>
>>>
>>
>> Regards,
>> Pawel
>>
>
>--
>Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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