Re: [PATCH v12 2/6] video: add of helper for videomode

[Steffen Trumtrar <s.trumtrar@pengutronix.de>]

Hi!

On Wed, Nov 21, 2012 at 10:12:43AM +0000, Manjunathappa, Prakash wrote:
> Hi Steffen,
> 
> On Tue, Nov 20, 2012 at 21:24:52, Steffen Trumtrar wrote:
> > +/**
> > + * of_get_display_timings - parse all display_timing entries from a device_node
> > + * @np: device_node with the subnodes
> > + **/
> > +struct display_timings *of_get_display_timings(const struct device_node *np)
> > +{
> > +	struct device_node *timings_np;
> > +	struct device_node *entry;
> > +	struct device_node *native_mode;
> > +	struct display_timings *disp;
> > +
> > +	if (!np) {
> > +		pr_err("%s: no devicenode given\n", __func__);
> > +		return NULL;
> > +	}
> > +
> > +	timings_np = of_find_node_by_name(np, "display-timings");
> 
> I get below build warnings on this line
> drivers/video/of_display_timing.c: In function 'of_get_display_timings':
> drivers/video/of_display_timing.c:109:2: warning: passing argument 1 of 'of_find_node_by_name' discards qualifiers from pointer target type
> include/linux/of.h:167:28: note: expected 'struct device_node *' but argument is of type 'const struct device_node *'
> 
> > + * of_display_timings_exists - check if a display-timings node is provided
> > + * @np: device_node with the timing
> > + **/
> > +int of_display_timings_exists(const struct device_node *np)
> > +{
> > +	struct device_node *timings_np;
> > +
> > +	if (!np)
> > +		return -EINVAL;
> > +
> > +	timings_np = of_parse_phandle(np, "display-timings", 0);
> 
> Also here:
> drivers/video/of_display_timing.c: In function 'of_display_timings_exists':
> drivers/video/of_display_timing.c:209:2: warning: passing argument 1 of 'of_parse_phandle' discards qualifiers from pointer target type
> include/linux/of.h:258:28: note: expected 'struct device_node *' but argument is of type 'const struct device_node *'
> 

The warnings are because the of-functions do not use const pointers where they
should. I had two options: don't use const pointers even if they should be and
have no warnings or use const pointers and have a correct API. (Third option:
send patches for of-functions). I chose the second option.

Regards,
Steffen


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