Re: [PATCH v2 2/6] arm64: dts: freescale: imx8mp-verdin: Add Cortex-M7 UART_4 overlay

[Frank Li]

On Thu, Oct 01, 2026 at 01:44:10PM +0200, Ernest Van Hoecke wrote:
> From: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
>
> Verdin UART_4 can be assigned to Cortex-M7 firmware. Add an overlay
> that marks the UART as reserved so Linux does not claim the port.
>
> The overlay is also combined with the Verdin iMX8M Plus Development
> Board device tree to provide a ready-to-use DTB for the non-WiFi SoM
> variant. UART_4 carries Bluetooth on WiFi SoMs.
>
> Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
> ---
>  arch/arm64/boot/dts/freescale/Makefile                     |  3 +++
>  arch/arm64/boot/dts/freescale/imx8mp-verdin-uart4-mcu.dtso | 14 ++++++++++++++

I remember at another thread said, use imx-uart4-mcu.dtso for all uart4
case. It doesn't affect ov5460 part.

Frank

>  2 files changed, 17 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/freescale/Makefile b/arch/arm64/boot/dts/freescale/Makefile
> index 23e2684d6923..649be5b6aab4 100644
> --- a/arch/arm64/boot/dts/freescale/Makefile
> +++ b/arch/arm64/boot/dts/freescale/Makefile
> @@ -736,6 +736,7 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-dahlia-dsi-to-hdmi.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-dahlia-panel-cap-touch-10inch-dsi.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-dahlia.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-dev-dsi-to-hdmi.dtb
> +dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-dev-uart4-mcu.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-dev.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-ivy.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-mallow.dtb
> @@ -744,6 +745,7 @@ dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-yavia.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-nonwifi-zinnia.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-panel-cap-touch-10inch-dsi.dtbo
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-panel-cap-touch-7inch-dsi.dtbo
> +dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-uart4-mcu.dtbo
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-wifi-dahlia-dsi-to-hdmi.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-wifi-dahlia-panel-cap-touch-10inch-dsi.dtb
>  dtb-$(CONFIG_ARCH_MXC) += imx8mp-verdin-wifi-dahlia.dtb
> @@ -761,6 +763,7 @@ imx8mp-verdin-nonwifi-dahlia-dsi-to-hdmi-dtbs := imx8mp-verdin-nonwifi-dahlia.dt
>  imx8mp-verdin-nonwifi-dahlia-panel-cap-touch-10inch-dsi-dtbs := imx8mp-verdin-nonwifi-dahlia.dtb \
>  	imx8mp-verdin-panel-cap-touch-10inch-dsi.dtbo
>  imx8mp-verdin-nonwifi-dev-dsi-to-hdmi-dtbs := imx8mp-verdin-nonwifi-dev.dtb imx8mp-verdin-dsi-to-hdmi.dtbo
> +imx8mp-verdin-nonwifi-dev-uart4-mcu-dtbs := imx8mp-verdin-nonwifi-dev.dtb imx8mp-verdin-uart4-mcu.dtbo
>  imx8mp-verdin-nonwifi-yavia-dsi-to-hdmi-dtbs := imx8mp-verdin-nonwifi-yavia.dtb imx8mp-verdin-dsi-to-hdmi.dtbo
>  imx8mp-verdin-wifi-dahlia-dsi-to-hdmi-dtbs := imx8mp-verdin-wifi-dahlia.dtb imx8mp-verdin-dsi-to-hdmi.dtbo
>  imx8mp-verdin-wifi-dahlia-panel-cap-touch-10inch-dsi-dtbs := imx8mp-verdin-wifi-dahlia.dtb \
> diff --git a/arch/arm64/boot/dts/freescale/imx8mp-verdin-uart4-mcu.dtso b/arch/arm64/boot/dts/freescale/imx8mp-verdin-uart4-mcu.dtso
> new file mode 100644
> index 000000000000..74d90b39faec
> --- /dev/null
> +++ b/arch/arm64/boot/dts/freescale/imx8mp-verdin-uart4-mcu.dtso
> @@ -0,0 +1,14 @@
> +// SPDX-License-Identifier: GPL-2.0-only OR MIT
> +/*
> + * Copyright (c) Toradex
> + *
> + * Verdin iMX8M Plus UART_4 for Cortex-M7
> + */
> +
> +/dts-v1/;
> +/plugin/;
> +
> +/* Verdin UART_4 */
> +&uart4 {
> +	status = "reserved";
> +};
>
> --
> 2.43.0
>
>