[PATCH v4 4/7] dts: qcs615-ride-u-boot.dtsi: Add reboot-mode support

[Sumit Garg]

On Wed, Apr 08, 2026 at 05:48:38PM +0530, Aswin Murugan wrote:
> The PM8150 PMIC on this platform uses the older PON (Power On) register
> architecture rather than dedicated SDAM regions found in newer PMIC
> generations. To enable reboot-mode functionality with the unified
> NVMEM-based approach, add a compatibility wrapper that exposes PON
> registers through the SDAM NVMEM interface.
> 
> Add device tree configuration:
> - NVMEM node with compatible "qcom,spmi-sdam" wrapping PON registers
> - Uses 'ranges' property to map the PON register block at offset 0x800
> - NVMEM cell at offset 0x8F (PON_SOFT_RB_SPARE register)
> - 7-bit field (bits [7:1]) for reboot reason, preserving bit 0
> - Mode mappings: bootloader=0x02, recovery=0x01
> 
> This wrapper allows the SDAM NVMEM driver to access PON registers
> transparently, providing a unified interface for both PON-based (older)
> and SDAM-based (newer) PMIC generations.
> 
> The PON_SOFT_RB_SPARE register persists across warm resets and is
> automatically cleared on power cycle.
> 
> Signed-off-by: Aswin Murugan <aswin.murugan at oss.qualcomm.com>
> ---
> Changes in v4:
> 1. Changed bits property as 'bits = <1 7>'
> 
> Changes in v3:
> 1. No change in v3
> ---
>  arch/arm/dts/qcs615-ride-u-boot.dtsi | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/arch/arm/dts/qcs615-ride-u-boot.dtsi b/arch/arm/dts/qcs615-ride-u-boot.dtsi
> index 68fffc70fcb..687e9a67a9f 100644
> --- a/arch/arm/dts/qcs615-ride-u-boot.dtsi
> +++ b/arch/arm/dts/qcs615-ride-u-boot.dtsi
> @@ -11,4 +11,30 @@
>  		      <0x0 0xc0000000 0x0 0xc0000000>,
>  		      <0x1 0x80000000 0x1 0x00000000>;
>  	};
> +
> +	reboot-mode {
> +		compatible = "nvmem-reboot-mode";
> +		nvmem-cells = <&reboot_reason>;
> +		nvmem-cell-names = "reboot-mode";
> +
> +		mode-bootloader = <0x02>;
> +		mode-recovery   = <0x01>;
> +	};
> +};
> +
> +&pm8150_0 {
> +	/* Virtual NVMEM node for PON-based reboot reason storage */
> +	nvram at 800 {
> +		compatible = "qcom,spmi-sdam";
> +		reg = <0x800>;
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		ranges = <0x00 0x800 0x100>;
> +
> +		/* Reboot reason cell at PON_SOFT_RB_SPARE (0x88F) */
> +		reboot_reason: reboot-reason at 8f {
> +			reg = <0x8f 0x1>;
> +			bits = <1 7>;
> +		};
> +	};

Please push this DTS feature patch to upstream kernel. There has to be
proper DT bindings for new compatible being added.

-Sumit