Re: [PATCH 3/7] ARM: dts: imx6q-apalis: Add Toradex Capacitive Touch Display 10.1" LVDS

[Frank Li]

On Mon, Oct 26, 2026 at 12:11:49PM +0100, Francesco Dolcini wrote:
> Hello Frank,
>
> On Tue, Oct 20, 2026 at 12:38:51PM -0400, Frank Li wrote:
> > On Mon, Oct 05, 2026 at 09:53:19AM +0200, Francesco Dolcini wrote:
> > > Hello Frank,
> > >
> > > On Fri, Oct 02, 2026 at 11:28:33AM -0500, Frank Li wrote:
> > > > On Fri, Oct 02, 2026 at 10:18:24AM +0200, Francesco Dolcini wrote:
> > > > > On Thu, Oct 01, 2026 at 11:26:05AM -0500, Frank Li wrote:
> > > > > > On Thu, Oct 01, 2026 at 12:52:53PM -0300, Leonardo Costa wrote:
> > > > > > > From: Leonardo Costa <leonardo.costa@xxxxxxxxxxx>
> > > > > > >
> > > > > > > Add a device tree overlay for the Toradex Capacitive Touch Display 10.1"
> > > > > > > LVDS connected via the Apalis iMX6 LDB.
> > > > > > >
> > > > > > > The panel is a LogicTechno LT170410-2WHC 10.1" WXGA IPS LCD and the
> > > > > > > touch input is provided by an Atmel MaxTouch capacitive touch
> > > > > > > controller.
> > > > > > >
> > > > > > > Remove the panel-lvds node from the Apalis iMX6 dtsi, as it is an
> > > > > > > external component that does not exist at the SoM level.
> > > > > > >
> > > > > > > The overlay is also combined with the Apalis iMX6 V1.2 Ixora Carrier
> > > > > > > Board V1.2 device tree to provide a ready-to-use DTB.
> > > > > > >
> > > > > > > Link: https://developer.toradex.com/hardware/accessories/displays/capacitive-touch-display-101inch-lvds
> > > > > > > Signed-off-by: Leonardo Costa <leonardo.costa@xxxxxxxxxxx>
> > > > > > > ---
> > > > > > >  arch/arm/boot/dts/nxp/imx/Makefile            |  6 +++
> > > > > > >  ...6q-apalis-panel-cap-touch-10inch-lvds.dtso | 53 +++++++++++++++++++
> > > > > > >  arch/arm/boot/dts/nxp/imx/imx6qdl-apalis.dtsi | 13 -----
> > > > > > >  3 files changed, 59 insertions(+), 13 deletions(-)
> > > > > > >  create mode 100644 arch/arm/boot/dts/nxp/imx/imx6q-apalis-panel-cap-touch-10inch-lvds.dtso
> > > > > >
> > > > > > similar 7" case, add panel module name in file
> > > > > >
> > > > > > imx6q-apalis-lvds-panel-lt170410.dtso
> > > > >
> > > > > This does not work, sorry, the current name is the correct one, for
> > > > > various reasons:
> > > > >
> > > > >  - the product is a display made with a specific connector, touch
> > > > >    controller and display and more. The actual panel is just part of it
> > > > >  - the current name wholly describe the product, it's a public product
> > > > >    with an official name, all of that is clearly linked in the commit
> > > > >    message and comments. there is no ambiguity.
> > > > >  - the same toradex accessories are not module specific, they are used
> > > > >    across multiple families/carrier board. It is a whole ecosystem that is
> > > > >    building on top of standardized interfaces and connectors. The same
> > > > >    overlay file is available for multiple boards and in multiple SoC
> > > > >    vendor directory (as of now TI and NXP, soon we are going to have
> > > > >    also QCOM). Having a consistent naming scheme is important, we cannot
> > > > >    call the same things differently every time.
> > > > >  - there was a situation in which we did a new product revision of a
> > > > >    display, specifically the "Toradex Capacitive Touch Display 10.1"
> > > > >    LVDS" there are two versions. The official product name is the same,
> > > > >    apart an additional version number, one is version1, the other is
> > > > >    version2. They have differences, and it's not just the panel, more
> > > > >    stuff changed, so having the panel name in the filename will not
> > > > >    help. v2 support is already in [1], for reference.
> > > > >  - the toradex naming scheme is not encoding the actual part number used
> > > > >    in the product name, for example we have apalis imx6 v1.2 that uses a
> > > > >    different touch/adc than previous apalis imx v1.1. The product has a
> > > > >    different schematics, different BoM and so on
> > > >
> > > > Do you have schematics number to identify it?
> > >
> > > Why do you ask specifically about schematics? We have schematics and we
> > > have a way to identify a product to the related schematic. The way we
> > > identify schematics, whatever is a number, a string, or anything else
> > > seems not relevant to me.
> > >
> > > But yes, answering you question, we do have schematics and a unique
> > > way to identify them, and it's not using "numbers".
> > >
> > > What matters here, is that Toradex products have a unique number,
> > > and we have a way to trace product revisions.
> > >
> > > So, for each product we have
> > >
> > > <product name> <pid>
> > >
> > > and <pid> is 8 digits, the first 4 digits is the end customer product
> > > definition, and it matches with the product name, and the last 4 digits
> > > is the product revision.
> > >
> > > All of that is documented, see https://developer.toradex.com/hardware/hardware-resources/general-product-information/ordering-information-and-product-identification-pid-pid4-and-pid8/,
> > > and this is what is used for any kind of product traceability.
> > >
> > > Staying on our LVDS 10inch panel example
> > >
> > > Capacitive Touch Display 10.1" LVDS | PID4: 1212 | PID8: 12121000 | (version 1)
> > > Capacitive Touch Display 10.1" LVDS | PID4: 1212 | PID8: 12122000 | (version 2)
> >
> > include  12121000 in your file names.
>
> That would result in filenames such as:
>
>   imx6q-apalis-tdx-panel-cap-touch-10inch-lvds-12121000.dtbo
>   imx6q-apalis-tdx-panel-cap-touch-10inch-lvds-12122000.dtbo
>
> While technically correct, this creates a usability problem. PID8
> ("12121000" is what is called a PID8 in Toradex product naming/number
> scheme) tracks hardware revisions, including changes that do not affect
> the DT, such as passive components or mechanical changes.
>
> A user with PID8 12122001 would not know which overlay to use, and
> duplicating identical overlays for every hardware revision makes no sense.
>
> I therefore propose:
>
> imx6q-apalis-tdx-panel-cap-touch-10inch-lvds-v1.dtbo
> imx6q-apalis-tdx-panel-cap-touch-10inch-lvds-v2.dtbo

It is okay.

> >
...
> > Ideally, rpi-display-2-7in.dtso should reused for all boards, which use
> > rpi defined connectors. Now exsiting these combinations reason is current
> > nexus node is not good enough. but we face to this directions.
> >
> > And anyway, rpi-display-2-7in is not good name because rpi many produce
> > difference 2-7in panels in future.
>
> This is an existing upstream naming convention, already reviewed and
> accepted by multiple maintainers.


The existing doesn't means good enough. That's reason why there are hundreds
patches each days.

Our goal is making thing better.

Frank

>
> Product naming and versioning are the responsibility of the manufacturer
> (whatever is raspberrypi or toradex).  I do not think we should
> second-guess those decisions without a concrete technical issue.
>
> Francesco
>