OMAPDSS: omap5 SYNC_LOST error with DPI/LCD

[Vikas Patil]

Hi Tomi,

Thank a lot  for your inputs and patch info.

It seems I cannot apply those patches straight away as it is based on
3.6-rc4 and I am using 3.4.25, between these two, it seems significant code
changes for DSS related code.

I am using 3.4.25 kernel from TI for OMAP5 evm, it has been modified as per
our platform requirement which is having OMAP5 ES2.0 revision.

I am trying to use the panel driver for DPI interface(i.e.
Kernel\drivers\video\omap2\displays\panel-generic-dpi.c). So DSS and panel
driver path are as follows

Kernel\drivers\video\omap2\dss\dpi.c,dss.c,display.c,dss_features.c etc
Kernel\drivers\video\omap2\displays\panel-generic-dpi.c

soc specific:
Kernel\arch\arm\mach-omap2\omap5_es2\clkt_clksel.c,
clkt_dpll.c,clock.c,cm44xx_54xx.c etc

omapdrm path:
Kernel\drivers\staging\omapdrm

In case for working HDMI port, we are using:
Kernel\drivers\video\omap2\dss\hdmi.c
Kernel\drivers\video\omap2\dss\hdmi_panel.c

I think this would require considerable amount of understanding on dss
architecture and effort to backport some of the things, write new driver
fro TDF19988 and make DPI interface working for our platform for someone
like me who has just started working on DSS/Display.

Regards,
Vikash

On Mon, May 12, 2014 at 5:28 PM, Tomi Valkeinen <tomi.valkeinen at ti.com>wrote:

> On 12/05/14 14:33, Vikas Patil wrote:
> > Hi,
> >
> > Re-posting as previous posting was rejected due to length.
> >
> > Forgot to mention, DPI pins are connected to TDF19988 chip for HDMI
> > conversion.
> > I have build the driver for it from
> >
> https://gitorious.org/thierryreding/linux/source/e7792ce2da5ded80861db787ace9b57ecf7bc96c:drivers/gpu/drm/i2c/tda998x_drv.c
> .
> > Is this the correct driver for it?
>
> That driver cannot be used with omapdrm, which uses omapdss. There's no
> TDF19988 driver for omapdss (at least in the mainline), so you need to
> write one.
>
> > Also I am trying to use the generic-dpi-panel driver for this with
> > OMAP5. It seems I also need to add support for TDF19988 somewhere in
> > omapdrm or lcd/panel driver by calling drm_i2c_encoder_init to
> > initialize it. Can I use somecode from ticldc driver or driver itself?
> > Could you please give some inputs, how should I proceed further to
> > adding support for TDF19988 for which the input is coming from DPI
> > interface?
>
> You need to write a driver for it. Something similar to
> drivers/video/fbdev/omap2/displays-new/encoder-tfp410.c, except tfp410
> is quite simple one.
>
> But I think you said you're based on some old customized kernel, so I
> don't know which kind of omapdss driver you have there, so the mainline
> tfp410 cannot probably be used as an example. Most likely the omapdss
> drivers for your kernel are located in drivers/video/omap2/displays/
> directory.
>
>  Tomi
>
>
>
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