Message-ID: <DM6PR07MB55293FED0365CA0B70271F45DD0A0@DM6PR07MB5529.namprd07.prod.outlook.com>
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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