[PATCH v2] pwm: pwm-omap-dmtimer: return -EPROBE_DEFER if no dmtimer platform data

[ladis@linux-mips.org (Ladislav Michl)]

On Thu, Jul 26, 2018 at 04:37:05PM -0400, David Rivshin wrote:
> On Thu, 26 Jul 2018 20:54:26 +0200
> Ladislav Michl <ladis@linux-mips.org> wrote:
> 
> > On Thu, Jul 26, 2018 at 09:36:58AM -0400, David Rivshin wrote:
> > > From: David Rivshin <DRivshin@allworx.com>
> > > 
> > > If a pwm-omap-dmtimer is probed before the dmtimer it uses, the platform
> > > data won't be set yet.
> > > 
> > > Fixes: ac30751df953 ("ARM: OMAP: pdata-quirks: Remove unused timer pdata")
> > > Cc: <stable@vger.kernel.org> # 4.17+
> > > Signed-off-by: David Rivshin <drivshin@allworx.com>
> > > Acked-by: Pavel Machek <pavel@ucw.cz>
> > > Tested-by: Pavel Machek <pavel@ucw.cz>
> > > ---
> > > Changes in v2:
> > > * Added Pavel's Acked-by/Tested-by [1]
> > > 
> > > [1] https://lkml.org/lkml/2018/7/16/346
> > > 
> > >  drivers/pwm/pwm-omap-dmtimer.c | 5 +++--
> > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c
> > > index 665da3c8fbceb..d3d7ea7a53146 100644
> > > --- a/drivers/pwm/pwm-omap-dmtimer.c
> > > +++ b/drivers/pwm/pwm-omap-dmtimer.c
> > > @@ -264,8 +264,9 @@ static int pwm_omap_dmtimer_probe(struct platform_device *pdev)
> > >  
> > >  	timer_pdata = dev_get_platdata(&timer_pdev->dev);
> > >  	if (!timer_pdata) {
> > > -		dev_err(&pdev->dev, "dmtimer pdata structure NULL\n");
> > > -		ret = -EINVAL;
> > > +		dev_info(&pdev->dev,
> > > +			 "dmtimer pdata structure NULL, deferring probe\n");  
> > 
> > This seems to be a bit verbose for EPROBE_DEFER case. Could we either remove
> > it as it is done later in pdata->request_by_node(timer) failure case or at
> > least make it dev_dbg? Otherwise thank you and with mentioned change
> > Acked-by: Ladislav Michl <ladis@linux-mips.org>
> 
> Hi Ladislav, thanks for the review.
> 
> I had grepped through other drivers and found no consistent pattern. Some
> places used dev_err still, others reduced to one of dev_{warn,info,dbg}, 
> and others no message at all. Some messages mentioned they are deferring 
> the probe, other didn't. I was already getting a couple of dev_info from 
> the pinctrl core code, so I went that way. I figured the message might be
> useful to someone, but I don't feel strongly.

Well, pinctrl probe deferal message is a bit annoying. It really does not
tell us much as long as pins are correctly configured and in case they are
not it is useless as well :)

> I personally would lean to dev_dbg if you think dev_info is too harsh, 
> just in case someone's board suddenly isn't working after upgrade. But 
> I'm certainly willing to remove the message entirely if you feel strongly,
> or anyone else cares to weigh in.

I'm fine with dev_dbg as well.

Thank you,
	ladis

> > 
> > > +		ret = -EPROBE_DEFER;
> > >  		goto put;
> > >  	}
> > >  
> > > 
> > > base-commit: d72e90f33aa4709ebecc5005562f52335e106a60
> > > -- 
> > > 2.17.1