Re: [PATCH] USB: host: ehci: Add error handling inehci_mxc_drv_probe()

[Tang Bin]

Hi, Greg:

On 2020/5/8 19:48, Greg KH wrote:
> On Fri, May 08, 2020 at 07:44:53PM +0800, Tang Bin wrote:
> > The function ehci_mxc_drv_probe() does not perform sufficient error
> > checking after executing platform_get_irq(), thus fix it.
> >
> > Fixes: 7e8d5cd93fa ("USB: Add EHCI support for MX27 and MX31 based boards")
> > Signed-off-by: Zhang Shengju <zhangshengju@xxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Tang Bin <tangbin@xxxxxxxxxxxxxxxxxxxx>
> > ---
> >   drivers/usb/host/ehci-mxc.c | 2 ++
> >   1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/usb/host/ehci-mxc.c b/drivers/usb/host/ehci-mxc.c
> > index a1eb5ee77..a0b42ba59 100644
> > --- a/drivers/usb/host/ehci-mxc.c
> > +++ b/drivers/usb/host/ehci-mxc.c
> > @@ -50,6 +50,8 @@ static int ehci_mxc_drv_probe(struct platform_device *pdev)
> >   	}
> >   
> >   	irq = platform_get_irq(pdev, 0);
> > +	if (irq < 0)
> > +		return irq;
> <= ?

In the file 'drivers/base/platform.c'ï the function platform_get_irq() 
is explained and used as follows:

ÂÂÂÂ * Gets an IRQ for a platform device and prints an error message if 
finding the
ÂÂÂÂ * IRQ fails. Device drivers should check the return value for 
errors so as to
ÂÂÂÂ * not pass a negative integer value to the request_irq() APIs.
ÂÂÂÂ *
ÂÂÂÂ * Example:
ÂÂÂÂ *ÂÂÂ ÂÂÂ int irq = platform_get_irq(pdev, 0);
ÂÂÂÂ *ÂÂÂ ÂÂÂ if (irq < 0)
ÂÂÂÂ *ÂÂÂ ÂÂÂ ÂÂÂ return irq;
ÂÂÂÂ *
ÂÂÂÂ * Return: IRQ number on success, negative error number on failure.

And in my hardware experiment, even if I set the irq failed deliberately 
in the DTS, the returned value is negative instead of zero.

Thanks for your patience and replay.

Tang Bin