Re: [PATCH] make ds1wm driver to check ds1wm_platform_data pointer against NULL

[Evgeniy Polyakov <johnpol@2ka.mipt.ru>]

On Fri, Nov 09, 2007 at 05:02:38PM -0800, Andrew Morton (akpm@linux-foundation.org) wrote:
> > @@ -351,6 +351,10 @@ static int ds1wm_probe(struct platform_device *pdev)
> >  		goto err0;
> >  	}
> >  	plat = pdev->dev.platform_data;
> > +	if (!plat) {
> > +		ret = -ENXIO;
> > +		goto err0;
> > +	}
> >  	ds1wm_data->bus_shift = plat->bus_shift;
> >  	ds1wm_data->pdev = pdev;
> >  	ds1wm_data->pdata = plat;
> 
> I don't understand this change.  Could you please provide some more details
> regarding what problem it is solving?  How can pdev->dev.platform_data==NULL
> come about?

If I understood correctly, it is posible to call platform's probe
callback without previously calling platform_device_add_data() to setup
platform_data.

But actually I failed to find any user of this platform driver in
vanilla kernel, so it is hard to say if driver is used properly or not
by external modules, and thus this change is very likely valid.

-- 
	Evgeniy Polyakov