Re: [PATCH v2] Add DT support for Octavo Systems OSD3358-SM-RED based on TI AM335x

[Russell King - ARM Linux <linux@armlinux.org.uk>]

On Mon, Jul 09, 2018 at 02:45:17PM -0500, Neeraj Kumar Reddy Dantu wrote:
>  > This should not be "tda19988" as the node name - DT requires generic
> > names, like "hdmi-encoder".
> 
> Thanks.Will fix in v3
> 
> > Can you set 24-bit RGB mode with the above configuration - presumably
> > the colours will come out wrong?
> > Exactly what is the wiring between the lcdc and tda998x?
> 
> You can set mapping for lcd interface between pins with video-ports. See
> TDA19988 datasheet, Table 4:
> https://media.digikey.com/pdf/Data%20Sheets/NXP%20PDFs/TDA19988_DS_21_july_2011.pdf
> .
> The property is optional and not used in the board. DT bindings:
> https://www.kernel.org/doc/Documentation/devicetree/bindings/display/bridge/tda998x.txt
> 
> This board uses 15 pin RGB565 interface.

As maintainer of the TDA998x driver, I know what the TDA998x is
capable of, I already have the datasheets, and I know the binding
document.

What I'm asking about is about the specifics of your board's
implementation and why you've written what you have in your DT
file.  You haven't answered my specific questions either.

> 
> Regards,
> Neeraj
> 
> On Mon, Jul 9, 2018 at 6:43 AM Russell King - ARM Linux <
> linux@armlinux.org.uk> wrote:
> 
> > On Fri, Jul 06, 2018 at 08:00:51PM +0000, Neeraj Dantu wrote:
> > > +&lcdc {
> > > +     status = "okay";
> > > +
> > > +     /* If you want to get 24 bit RGB and 16 BGR mode instead of
> > > +      * current 16 bit RGB and 24 BGR modes, set the propety
> > > +      * below to "crossed" and uncomment the video-ports -property
> > > +      * in tda19988 node.
> > > +      */
> > > +     blue-and-red-wiring = "straight";
> > ...
> > > +&i2c0 {
> > > +     tda19988: tda19988 {
> >
> > This should not be "tda19988" as the node name - DT requires generic
> > names, like "hdmi-encoder".
> >
> > ...
> > > +             /* Convert 24bit BGR to RGB, e.g. cross red and blue
> > wiring */
> > > +             /* video-ports = <0x234501>; */
> >
> > Please explain more what's going on here.
> >
> > Can you set 24-bit RGB mode with the above configuration - presumably
> > the colours will come out wrong?
> >
> > Exactly what is the wiring between the lcdc and tda998x?
> >
> > --
> > RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
> > FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps
> > up
> > According to speedtest.net: 13Mbps down 490kbps up
> >

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 13.8Mbps down 630kbps up
According to speedtest.net: 13Mbps down 490kbps up