[PATCH v5 2/2] drm/bridge: lvds-codec: Add support for pixel data sampling edge select

Sam Ravnborg sam at ravnborg.org
Sun Oct 17 17:40:57 UTC 2021


Hi Marek,

On Sun, Oct 17, 2021 at 07:29:51PM +0200, Marek Vasut wrote:
> On 10/17/21 6:49 PM, Sam Ravnborg wrote:
> 
> [...]
> 
> > > +	/*
> > > +	 * Encoder might sample data on different clock edge than the display,
> > > +	 * for example OnSemi FIN3385 has a dedicated strapping pin to select
> > > +	 * the sampling edge.
> > > +	 */
> > > +	if (lvds_codec->connector_type == DRM_MODE_CONNECTOR_LVDS &&
> > > +	    !of_property_read_u32(dev->of_node, "pclk-sample", &val)) {
> > > +		lvds_codec->timings.input_bus_flags = val ?
> > > +			DRM_BUS_FLAG_PIXDATA_SAMPLE_POSEDGE :
> > > +			DRM_BUS_FLAG_PIXDATA_SAMPLE_NEGEDGE;
> > > +	}
> > > +
> > >   	/*
> > >   	 * The panel_bridge bridge is attached to the panel's of_node,
> > >   	 * but we need a bridge attached to our of_node for our user
> > >   	 * to look up.
> > >   	 */
> > >   	lvds_codec->bridge.of_node = dev->of_node;
> > > +	lvds_codec->bridge.timings = &lvds_codec->timings;
> > I do not understand how this will work. The only field that is set is timings.input_bus_flags
> > but any user will see bridge.timings is set and will think this is all
> > timing info.
> > 
> > Maybe I just misses something obvious?
> 
> Is there anything else in those timings that should be set ? See
> include/drm/drm_bridge.h around line 640
> 
> setup_time_ps/hold_time_ps/dual_link isn't supported by this driver, so it
> is 0 or false anyway, i.e. no change.

Just me being confused with display_timings. Patch looks good.
Reviewed-by: Sam Ravnborg <sam at ravnborg.org>

Ping me in a few days to apply it if there is no more feedback.

	Sam



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