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Date: Wed, 7 Oct 2020 03:12:52 +0000
From: Pawel Laszczak <pawell@...ence.com>
To: Roger Quadros <rogerq@...com>,
"balbi@...nel.org" <balbi@...nel.org>
CC: Peter Chen <peter.chen@....com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Rahul Kumar <kurahul@...ence.com>
Subject: RE: [PATCH] usb: cdns3: platform_get_irq_byname_optional instead
platform_get_irq_byname
Felipe,
Please ignore this patch. I will create the new one.
It's no sense to send the v2 because I have to change the patch name,
Description and contents.
Regards,
Pawel,
>Roger,
>
>>Pawel,
>>
>>On 05/10/2020 08:54, Pawel Laszczak wrote:
>>> 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");
>>> ?
>>
>>Yes.
>>
>>>
>>> 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.
>>
>>Using platform_get_irq_byname_optional() says driver expects it is optional but
>>only to fail later. It will be confusing to new reader that's all. I leave it to
>>you to decide what approach to take.
>
>Thanks for clarification.
>I will send new patch with platform_get_irq_byname.
>
>Cheers,
>Pawel
>
>>
>>>>
>>>>>
>>>>>>
>>>>>>>
>>>>>>> A change was suggested during reviewing CDNSP driver by Chunfeng Yun.
>>>>>>>
>>>>>>> Signed-off-by: Pawel Laszczak <pawell@...ence.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
>>
>>--
>>Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>>Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
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