Re: [PATCH v4 1/6] drm/dsi: check for CONFIG_OF when defining of_mipi_dsi_device_add

[Archit Taneja]

On 1/21/2016 9:01 PM, Thierry Reding wrote:
> On Thu, Dec 10, 2015 at 06:11:35PM +0530, Archit Taneja wrote:
> > of_mipi_dsi_device_add is used only when CONFIG_OF is enabled. It
> > currently works if OF support is disabled, but this will change
> > when we add more functionality to it.
> >
> > Define the original func if CONFIG_OF is enabled. Define a dummy func
> > otherwise.
> >
> > Signed-off-by: Archit Taneja <architt@xxxxxxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/drm_mipi_dsi.c | 8 ++++++++
> >   1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_mipi_dsi.c b/drivers/gpu/drm/drm_mipi_dsi.c
> > index 2d5ca8ee..bced235 100644
> > --- a/drivers/gpu/drm/drm_mipi_dsi.c
> > +++ b/drivers/gpu/drm/drm_mipi_dsi.c
> > @@ -129,6 +129,7 @@ static int mipi_dsi_device_add(struct mipi_dsi_device *dsi)
> >   	return device_add(&dsi->dev);
> >   }
> >
> > +#if IS_ENABLED(CONFIG_OF)
> >   static struct mipi_dsi_device *
> >   of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
> >   {
> > @@ -170,6 +171,13 @@ of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
> >
> >   	return dsi;
> >   }
> > +#else
> > +static struct mipi_dsi_device *
> > +of_mipi_dsi_device_add(struct mipi_dsi_host *host, struct device_node *node)
> > +{
> > +	return NULL;
> > +}
> > +#endif
>
> The OF implementation of this function never returns NULL, so perhaps
> this should return an ERR_PTR()-encoded error code instead? This isn't
> really important because we never check the return value in the one
> call-site that we have, which I guess could be an argument for removing
> the return value altogether...

You're right. I'll replace this with ERR_PTR(-ENODEV). Maybe we could
keep the return value in case we use it in the future.

Thanks,
Archit

> Thierry

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