[RFC 12/16] drm/armada: add bus-width property to the output endpoint

[Russell King - ARM Linux]

On Thu, Jan 03, 2019 at 02:20:00PM +0100, Lubomir Rintel wrote:
> On Thu, 2019-01-03 at 13:15 +0000, Russell King - ARM Linux wrote:
> > On Tue, Dec 18, 2018 at 04:37:38PM +0100, Lubomir Rintel wrote:
> > > This makes it possible to choose a different pixel format for the
> > > endpoint. Modelled after what other LCD controllers use, including
> > > marvell,pxa2xx-lcdc and atmel,hlcdc-display-controller and perhaps
> > > more.
> > > 
> > > Signed-off-by: Lubomir Rintel <lkundrak at v3.sk>
> > > ---
> > >  drivers/gpu/drm/armada/armada_crtc.c | 26
> > > +++++++++++++++++++++++++-
> > >  1 file changed, 25 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/armada/armada_crtc.c
> > > b/drivers/gpu/drm/armada/armada_crtc.c
> > > index da9360688b55..5400fb925bcd 100644
> > > --- a/drivers/gpu/drm/armada/armada_crtc.c
> > > +++ b/drivers/gpu/drm/armada/armada_crtc.c
> > > @@ -724,6 +724,8 @@ static int armada_drm_crtc_create(struct
> > > drm_device *drm, struct device *dev,
> > >  	struct armada_private *priv = drm->dev_private;
> > >  	struct armada_crtc *dcrtc;
> > >  	struct drm_plane *primary;
> > > +	struct device_node *endpoint;
> > > +	u32 bus_width = 24;
> > >  	void __iomem *base;
> > >  	int ret;
> > >  
> > > @@ -744,8 +746,30 @@ static int armada_drm_crtc_create(struct
> > > drm_device *drm, struct device *dev,
> > >  	dcrtc->base = base;
> > >  	dcrtc->num = drm->mode_config.num_crtc;
> > >  	dcrtc->clk = ERR_PTR(-EINVAL);
> > > -	dcrtc->cfg_dumb_ctrl = DUMB24_RGB888_0;
> > >  	dcrtc->spu_iopad_ctrl = CFG_VSCALE_LN_EN | CFG_IOPAD_DUMB24;
> > > +
> > > +	endpoint = of_get_next_child(port, NULL);
> > > +	of_property_read_u32(endpoint, "bus-width", &bus_width);
> > > +	of_node_put(endpoint);
> > > +
> > > +	switch (bus_width) {
> > > +	case 12:
> > > +		dcrtc->cfg_dumb_ctrl = DUMB12_RGB444_0;
> > > +		break;
> > > +	case 16:
> > > +		dcrtc->cfg_dumb_ctrl = DUMB16_RGB565_0;
> > > +		break;
> > > +	case 18:
> > > +		dcrtc->cfg_dumb_ctrl = DUMB18_RGB666_0;
> > > +		break;
> > > +	case 24:
> > > +		dcrtc->cfg_dumb_ctrl = DUMB24_RGB888_0;
> > > +		break;
> > > +	default:
> > > +		DRM_ERROR("unsupported bus width: %d\n", bus_width);
> > > +		return -EINVAL;
> > > +	}
> > > +
> > 
> > This needs to default to 24bpp if the property is not present.
> 
> It actually does: bus_width is initialized to 24 and
> of_property_read_u32() does not change it if the property is not
> present.
> 
> Perhaps the style is poor and I should just set the bus_width=24 in the
> case's default branch instead.

No, that's fine then.  Thanks for pointing that out.

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