Re: [PATCH 6/6] arm64: dts: freescale: imx8mp-verdin: Add Mezzanine with Toradex Display 10.1" LVDS V2

[Frank Li <Frank.li@oss.nxp.com>]

On Wed, Oct 21, 2026 at 03:28:54PM -0300, Leonardo Costa wrote:
> Hi Frank,
>
> On Wed, Oct 21, 2026 at 09:56:06AM -0500, Frank Li wrote:
> > On Wed, Oct 21, 2026 at 07:39:36AM -0300, Leonardo Costa wrote:
> > > Hi Frank,
> > >
> > > On Thu, Aug 13, 2026 at 11:15:04AM -0500, Frank Li wrote:
> > > > On Thu, Aug 13, 2026 at 12:43:29PM -0300, Leonardo Costa wrote:
> > > > > On Thu, Aug 13, 2026 at 09:58:52AM -0500, Frank Li wrote:
> > > > > > On Thu, Aug 13, 2026 at 10:33:35AM -0300, Leonardo Costa wrote:
> > > > > > > From: Leonardo Costa <leonardo.costa@toradex.com>
> > > > > > >
> > > > > > > Add a device tree overlay enabling the Toradex Capacitive Touch Display
> > > > > > > 10.1" LVDS V2 on the Verdin Development Board with Verdin iMX8M Plus
> > > > > > > Mezzanine expansion board. The panel connects via the i.MX8M Plus LCDIF
> > > > > > > on the Mezzanine LVDS interface (J10). The panel is an Opto Logic
> > > > > > > SCX1001511GGC49 10.1" WXGA TFT LCD LVDS and the touch input is provided
> > > > > > > by an ILITEK ILI251x capacitive touch controller.
> > > > > > >
> > > > > > > Link: https://developer.toradex.com/hardware/accessories/displays/capacitive-touch-display-101inch-lvds
> > > > > > > Link: https://developer.toradex.com/hardware/verdin-som-family/add-ons/verdin-imx8m-plus-mezzanine
> > > > > > > Signed-off-by: Leonardo Costa <leonardo.costa@toradex.com>
> > > > > > > ---
> > > > > >
> > > > > > what's difference with Add Toradex Capacitive Touch Display 10.1" LVDS V2
> > > > > >
> > > > > > why not share one dtso?
> > > > > >
> > > > > > Frank
> > > > >
> > > > > Hi Frank,
> > > > >
> > > > > There are two main differences:
> > > > >
> > > > > 1. The mezzanine one uses different backlight controll pins, so here we
> > > > > use the 'backlight-mezzanine' node, instead of the 'backlight' one, used
> > > > > in the one without the mezzanine.
> > > > >
> > > > > 2. The touchscreen GPIO and interrupt pins are also different with the
> > > > > mezzanine board.
> > > >
> > > >
> > > > And there are for imx8mm
> > > > https://lore.kernel.org/imx/20260724-v1-verdin-imx8mm-dtbos-v2-3-9d7988bd76f6@toradex.com/
> > > >
> > > > https://lore.kernel.org/imx/sr26lfvwasgcosfzcf4ydtwxwjjutlio2yqpgxldatpzjo7e4y@77k7gefnjzvl/
> > > >
> > > > Any ways, it is too late for 7.3, we have enough time for 7.4 to discuss
> > > > work on optimization solution.
> > > >
> > > > If use nexus connectors, we can share one dtso now if there are not
> > > > clock settings.
> > > >
> > > > clock patches is close to pick up
> > > > https://lore.kernel.org/all/20260807-schneider-v7-2-rc1-eip201-upstream-v5-1-8785f9531cf0@bootlin.com/
> > > >
> > > > Frank
> > >
> > > We tried to make the change to have a single overlay for the boards with and
> > > without the Mezzanine. However, in the current state of nexus connectors, this
> > > can't be done cleanly yet. When trying to describe the hardware at the level it
> > > exists in, following DT guidelines, and using nexus connectors, we still need
> > > two separate overlays to enable the native LVDS with and without the Mezzanine,
> > > so we don't really reduce the maintenance effort.
> > >
> > > See the changes at the end of the email, this is the closest we got to a
> > > correct and clean implementation that would allow the usage of a single
> > > overlay.
> > >
> > > The root cause of the issue is that we need to claim pinctrl_i2s_2_d_in_gpio
> > > and pinctrl_i2s_2_sync_gpio for the touchscreen on the Mallow Carrier Board.
> > > Ideally, they would be defined in the nexus connector, as shown in the diff.
> > > However, after enabling the connectors in the overlay, the pinctrl groups
> > > remain unclaimed. The reason is that nexus connectors have no driver to claim
> > > the groups.
> > >
> > >     root@verdin-imx8mp-14777535:~# cat /sys/kernel/debug/pinctrl/30330000.pinctrl/pinmux-pins
> > >     ...
> > >     pin 112 (MX8MP_IOMUXC_SAI3_RXD): (MUX UNCLAIMED) (GPIO UNCLAIMED)
> > >     pin 113 (MX8MP_IOMUXC_SAI3_TXFS): (MUX UNCLAIMED) (GPIO UNCLAIMED)
> > >     ...
> > >
> > > There is nowhere else in the carrier dtsi's where the pinctrls belong.
> > >
> > > The pinctrl groups thus need to be added to the touchscreen node defined in the
> > > overlay. However, the pins on the Development Board (which uses the Mezzanine)
> > > are muxed by pinctrl_gpio2 and pinctrl_gpio3. These groups are in the SoM dtsi,
> > > and we cannot claim them in the overlay. Because of this, the Mezzanine needs
> > > a different overlay, which doesn't claim any pinctrl.
> >
> > I met similar problem, see below.
> >
> > >
> > > We like the idea of a single overlay for both carriers, but sadly the nexus
> > > connectors, as they currently are, are not ready to enable this. We therefore
> > > have to move forward normally and once connector support matures, we're happy
> > > to refactor this and try to reduce the amount of overlays for the Verdin iMX8MP
> > > and for other modules.
> > >
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mp-verdin-dev.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-verdin-dev.dtsi
> > > index 72a4f846d694..d73a7e9042ea 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mp-verdin-dev.dtsi
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mp-verdin-dev.dtsi
> > > @@ -4,6 +4,41 @@
> > >   */
> > >
> > >  / {
> > > +	lvds_connector: lvds-mezzanine-connector {
> > > +		compatible = "toradex,lvds-connector";
> > > +		#gpio-cells = <2>;
> > > +		/* LVDS_BKL_EN_CON - Verdin GPIO 4 (SODIMM 212) */
> > > +		gpio-map = <0 0 &gpio1 6 0>;
> > > +		gpio-map-mask = <0xffffffff 0x0>;
> > > +		gpio-map-pass-thru = <0x0 0xffffffff>;
> > > +
> > > +		#pwm-cells = <3>;
> > > +		/* LVDS_PWM_CON - Verdin PWM_2 (SODIMM 16) */
> > > +		pwm-map = <0 0 0 &pwm2 0 0 0>;
> > > +		pwm-map-mask = <0x0 0x0 0x0>;
> > > +		pwm-map-pass-thru = <0x0 0xffffffff 0xffffffff>;
> > > +
> > > +		status = "disabled";
> > > +	};
> > > +
> > > +	touch_connector: touch-mezzanine-connector {
> > > +		compatible = "toradex,touch-connector";
> > > +		#gpio-cells = <2>;
> > > +		/* LVDS_TOUCH_RESET_CON# - Verdin GPIO_2 (SODIMM 208) */
> > > +		gpio-map = <0 0 &gpio1 1 0>;
> > > +		gpio-map-mask = <0xffffffff 0x0>;
> > > +		gpio-map-pass-thru = <0x0 0xffffffff>;
> > > +
> > > +		#address-cells = <0>;
> > > +		#interrupt-cells = <2>;
> > > +		/* LVDS_TOUCH_INT_CON# - Verdin GPIO_3 (SODIMM 210) */
> > > +		interrupt-map = <0 IRQ_TYPE_EDGE_FALLING &gpio1 5 IRQ_TYPE_EDGE_FALLING>,
> > > +				<0 IRQ_TYPE_EDGE_RISING &gpio1 5 IRQ_TYPE_EDGE_RISING>;
> > > +		interrupt-map-mask = <0xffffffff 0xffffffff>;
> > > +
> > > +		status = "disabled";
> > > +	};
> > > +
> > >  	native-hdmi-connector {
> > >  		compatible = "hdmi-connector";
> > >  		label = "X37";
> > > diff --git a/arch/arm64/boot/dts/freescale/imx8mp-verdin-mallow.dtsi b/arch/arm64/boot/dts/freescale/imx8mp-verdin-mallow.dtsi
> > > index 846b36706821..736f034c7550 100644
> > > --- a/arch/arm64/boot/dts/freescale/imx8mp-verdin-mallow.dtsi
> > > +++ b/arch/arm64/boot/dts/freescale/imx8mp-verdin-mallow.dtsi
> > > @@ -11,6 +11,46 @@
> > >  #include <dt-bindings/leds/common.h>
> > >
> > >  / {
> > > +	lvds_connector: lvds-connector {
> > > +		compatible = "toradex,lvds-connector";
> > > +
> > > +		#gpio-cells = <2>;
> > > +		/* LVDS_BKL_EN_CON - Verdin I2S_2_D_OUT as GPIO (SODIMM 46) */
> > > +		gpio-map = <0 0 &gpio5 1 0>;
> > > +		gpio-map-mask = <0xffffffff 0x0>;
> > > +		gpio-map-pass-thru = <0x0 0xffffffff>;
> > > +
> > > +		#pwm-cells = <3>;
> > > +		/* LVDS_PWM_CON - Verdin PWM_2 (SODIMM 16) */
> > > +		pwm-map = <0 0 0 &pwm2 0 0 0>;
> > > +		pwm-map-mask = <0x0 0x0 0x0>;
> > > +		pwm-map-pass-thru = <0x0 0xffffffff 0xffffffff>;
> > > +
> > > +		status = "disabled";
> > > +	};
> > > +
> > > +	touch_connector: touch-connector {
> > > +		compatible = "toradex,touch-connector";
> > > +		pinctrl-names = "default";
> > > +		pinctrl-0 = <&pinctrl_i2s_2_d_in_gpio>,
> > > +			    <&pinctrl_i2s_2_sync_gpio>;
> >
> > Thank you try this method.  Can make a pre-defined label for it, such
> > such as touch_conn0_pinctrl_gpio0, touch_conn0_pinctrl_gpio1, ....
> >
> > So touch overlay use this label directly, like other port, i2c ...
> >
> > After nexus improve by support mapping pinctrl, only few line needs be
> > changes.
> >
> > The bad things is that it need define NULL pintctrl for i2c gpio expander.
> >
> > It is worth to try.
>
> Just to clarify, do you mean doing something like this in the Dev Board
> dtsi?
>
>     &iomuxc {
>         touch_conn0_pinctrl_gpio0: touchconn0gpio0grp {
>             fsl,pins = <>;
>         };

In your board,
	fsl,pins = <MX8MP_IOMUXC_SAI3_RXD__GPIO4_IO30 0x1c4>;   /* SODIMM 48 */

If use i2c gpio expander, which have not pinctrl, you can try
	touch_conn0_pinctrl_gpio0: touchconn0gpio0grp {};
Do you meet this case in your board design?

Frank

>
>         touch_conn0_pinctrl_gpio1: touchconn0gpio1grp {
>             fsl,pins = <>;
>         };
>     };
>
> This gives warnings in dtbs_check as it doesn't parse the pins array correctly:
>
>     arch/arm64/boot/dts/freescale/imx8mp-verdin-wifi-dev.dtb: pinctrl@30330000 (fsl,imx8mp-iomuxc): touchconn0gpio0grp:fsl,pins: True is not of type 'array'
>             from schema $id: http://devicetree.org/schemas/pinctrl/fsl,imx8m-pinctrl.yaml
>     arch/arm64/boot/dts/freescale/imx8mp-verdin-wifi-dev.dtb: pinctrl@30330000 (fsl,imx8mp-iomuxc): touchconn0gpio1grp:fsl,pins: True is not of type 'array'
>             from schema $id: http://devicetree.org/schemas/pinctrl/fsl,imx8m-pinctrl.yaml
>
> Is this what you really meant, or did I misunderstand?
>
> Leonardo