Re: [PATCH] usb: cdns3: platform_get_irq_byname_optional instead platform_get_irq_byname

[Roger Quadros]

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.

cheers,
-roger

> > > A change was suggested during reviewing CDNSP driver by Chunfeng Yun.
> > >
> > > Signed-off-by: Pawel Laszczak <pawell@xxxxxxxxxxx>
> > > ---
> > >    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