RE: [PATCH] tty: serial: imx: Add return value check for platform_get_irq()

[Anson Huang]

Hi, Uwe


> Subject: Re: [PATCH] tty: serial: imx: Add return value check for
> platform_get_irq()
> 
> Hello Anson,
> 
> On Mon, May 11, 2020 at 03:09:56PM +0800, Anson Huang wrote:
> > RX irq is required, so add return value check for platform_get_irq().
> >
> > Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>
> > ---
> >  drivers/tty/serial/imx.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index
> > f4d6810..f4023d9 100644
> > --- a/drivers/tty/serial/imx.c
> > +++ b/drivers/tty/serial/imx.c
> > @@ -2252,6 +2252,8 @@ static int imx_uart_probe(struct platform_device
> *pdev)
> >  		return PTR_ERR(base);
> >
> >  	rxirq = platform_get_irq(pdev, 0);
> > +	if (rxirq < 0)
> > +		return rxirq;
> >  	txirq = platform_get_irq_optional(pdev, 1);
> >  	rtsirq = platform_get_irq_optional(pdev, 2);
> 
> I'm not sure we need such a check as devm_request_irq fails if the return value
> of platform_get_irq() is bogus.
> 
> But if we decide this construct is good enough, the error reporting needs some
> love as currently it emits two error messages which is confusing.

>From the driver, the RX IRQ is always required, if it failed in platform_get_irq(), then the
rest of the code is NOT necessary to be executed, and also I am NOT sure if platform_get_irq()
failed, the devm_request_irq will always failed?

Not very understand about your last question, the platform_get_irq() already has error message printed
out, so no additional error message is needed in the check. If looking through all other drivers, most
of the platform_get_irq() are having the return value check, if it failed in platform_get_irq(), driver can
just return error from .probe().

Anson