RE: [PATCH -next] serial: imx: remove set but not used variable 'rtsirq'

[Andy Duan <fugang.duan@nxp.com>]

From: Leonard Crestez Sent: 2018年9月20日 16:51
> On Thu, 2018-09-20 at 08:45 +0200, Jiri Slaby wrote:
> > On 09/20/2018, 03:58 AM, YueHaibing wrote:
> > > Fixes gcc '-Wunused-but-set-variable' warning:
> > >
> > > drivers/tty/serial/imx.c: In function 'imx_uart_probe':
> > > drivers/tty/serial/imx.c:2198:20: warning:
> > >  variable 'rtsirq' set but not used [-Wunused-but-set-variable]
> > >
> > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c @@
> > > -2220,7 +2220,6 @@ static int imx_uart_probe(struct
> platform_device
> > > *pdev)
> > >
> > >  	rxirq = platform_get_irq(pdev, 0);
> > >  	txirq = platform_get_irq(pdev, 1);
> > > -	rtsirq = platform_get_irq(pdev, 2);
> >
> > I am not sure this is correct. platform_get_irq has side effects (like
> > enabling the IRQ). Are you sure this won't change the behaviour (this
> > is question mostly to IMX fellows)?
> 
> As far as I can tell there was a request_irq call for rtsirq which was
> removed by mistake in commit afe9cbb1a6ad ("serial: imx: drop support
> for IRDA"):
> 
> -               /* do not use RTS IRQ on IrDA */
> -               if (!USE_IRDA(sport)) {
> -                       ret = devm_request_irq(&pdev->dev, rtsirq,
> -                                              imx_rtsint, 0,
> -
> dev_name(&pdev->dev), sport);
> -                       if (ret)
> -                               return ret;
> -               }
> 
> This should have just removed the IRDA check and request rtsirq
> unconditionally. Nobody noticed this by testing RTS on imx1, this is an old
> chip and later variants have a single combined irq.
> 
> The correct fix for the warning would be to restore that request_irq.
> 
> --
> Regards,
> Leonard

Yes, your explain is very correct! Thanks for your comment.
We should restore rtsirq request that for i.MX1.

Regards,
Andy Duan