Re: [PATCH v2 3/3] ARM: dts: imx6q-apalis: Add VGA overlay

[Francesco Dolcini]

On Mon, Oct 26, 2026 at 09:25:20AM -0300, Leonardo Costa wrote:
> Hi Frank,
> 
> On Tue, Oct 20, 2026 at 11:01:30AM -0500, Frank Li wrote:
> > On Tue, Oct 20, 2026 at 07:33:10AM -0300, Leonardo Costa wrote:
> > > On Mon, Oct 19, 2026 at 02:37:41PM -0500, Frank Li wrote:
> > > > On Mon, Oct 19, 2026 at 07:17:16AM -0300, Leonardo Costa wrote:
> > > > > From: Leonardo Costa <leonardo.costa@xxxxxxxxxxx>
> > > > >
> > > > > Add a device tree overlay for the VGA output available on the Apalis
> > > > > Evaluation Board, which is driven from a parallel RGB interface passing
> > > > > through a non-programmable video DAC to a VGA connector, without VESA
> > > > > DDC I2C signals.
> > > > >
> > > > > The non-programmable video DAC consists of a simple resistor ladder that
> > > > > converts the digital 16-bit RGB signal to VGA. The VGA output is gated by
> > > > > an active-low data-enable signal.
> > > > >
> > > > > The overlay is also combined with the various Apalis Evaluation Board
> > > > > device trees to provide ready-to-use DTBs.
> > > > >
> > > > > Signed-off-by: Leonardo Costa <leonardo.costa@xxxxxxxxxxx>
> > > > > ---
> > > > >  arch/arm/boot/dts/nxp/imx/Makefile                 | 21 ++++++
> > > > >  .../boot/dts/nxp/imx/imx6q-apalis-eval-vga.dtso    | 80 ++++++++++++++++++++++
> > > >
> > > > what's difference with
> > > >
> > > > https://lore.kernel.org/imx/20261019-colibri-imx6-overlays-v1-5-e4d028727382@xxxxxxxxxxx/T/#u
> > > >
> > > > Is it possible share one dtso also?
> > > >
> > > > Frank
> > >
> > > Hi Frank,
> > >
> > > The Apalis iMX6 one needs to set up the connection between the IPU the
> > > LCD interface (endpoints ipu2_di0_disp0 and vga_display_in), and the
> > > Colibri iMX6 one uses a DVI connector instead of a VGA one. Most of all,
> > > the bridge on the Colibri iMX6 doesn't have any control signals, while
> > > this one on the Apalis iMX6 has an active-low data-enable signal
> > 
> > This make sense to use difference dtso to cover it. Is it use name
> > imx6q-ipu-di0-vga.dtso, because this dtso have not boards specific part,
> > which can reuse for other similar hardware? Or we can rename it when reuse
> > happen.
> 
> I think the overlay should be kept as imx6q-apalis-eval-vga.dtso. As it
> currently is, it's easy to identify the hardware it may be used with. If
> another board is added which uses the same interface in this same way,
> we can evaluate if it's adequate to change names for reusability.

2 more cents. There is no such other board in the toradex portfolio and
it's very unlikely we are going to build any new board with an old VGA
interface.

Francesco