Re: [PATCH 11/11] ARM: dts: ux500: Remove DB8500 EPOD regulators

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Critical] Removing the EPOD regulator nodes and consumer supply properties breaks backwards compatibility with older kernels.
- [Low] Removed EPOD regulators and `epod-supply` property are still marked as required in their respective YAML binding schemas, causing `make dtbs_check` to fail.
--

commit cc40a973d5076813fb2d1de31c4ef7f4d0231e78
Author: Linus Walleij <linusw@kernel.org>

ARM: dts: ux500: Remove DB8500 EPOD regulators

This commit deletes the obsolete DB8500 EPOD regulator nodes from the device
tree. It retains only the VAPE and VSMPS2 compatibility regulators.

> diff --git a/arch/arm/boot/dts/st/ste-dbx5x0.dtsi b/arch/arm/boot/dts/st/ste-dbx5x0.dtsi
> index fd6a075e4c93c..18727953a8630 100644
> --- a/arch/arm/boot/dts/st/ste-dbx5x0.dtsi
> +++ b/arch/arm/boot/dts/st/ste-dbx5x0.dtsi
> @@ -663,97 +663,17 @@ thermal: thermal@801573c0 {
>  				#thermal-sensor-cells = <0>;
>  			};
>  
> -			/*
> -			 * TODO: Delete these bogus regulators and replace with power
> -			 * domains.
> -			 */
>  			db8500-prcmu-regulators {
>  				compatible = "stericsson,db8500-prcmu-regulator";

[Severity: Low]
Does this commit also need to update the YAML binding schemas? 

It appears that Documentation/devicetree/bindings/mfd/stericsson,db8500-prcmu.yaml
still mandates the presence of deleted EPOD nodes (e.g., db8500_varm, db8500_sga) 
in its required: block, which could cause dtbs_check to fail.

[ ... ]

> @@ -1215,8 +1127,6 @@ gpu@a0300000 {
>  			clocks = <&prcmu_clk PRCMU_ACLK>, <&prcmu_clk PRCMU_SGACLK>;
>  			clock-names = "bus", "core";
>  			power-domains = <&pm_domains DOMAIN_SGA>;
> -			/* TODO: delete and replace with power-domain handling */
> -			mali-supply = <&db8500_sga_reg>;
>  		};

[Severity: Critical]
Does removing the mali-supply property and its target regulator break 
backwards compatibility with older kernels? 

Device trees are considered a stable ABI, and older kernels lacking the updated
ste-ux500-pm-domain driver might rely entirely on the legacy 
db8500-prcmu-regulator driver to power these components. 

By aggressively removing these regulators, older kernels might fall back to dummy
regulators and leave the physical hardware unpowered, leading to crashes when
drivers attempt to access unclocked and unpowered hardware registers.

>  
>  		mcde@a0350000 {
> @@ -1224,8 +1134,6 @@ mcde@a0350000 {
>  			reg = <0xa0350000 0x1000>;
>  			interrupts = <GIC_SPI 48 IRQ_TYPE_LEVEL_HIGH>;
>  			power-domains = <&pm_domains DOMAIN_B2R2_MCDE>;
> -			/* TODO: delete and replace with power-domain handling */
> -			epod-supply = <&db8500_b2r2_mcde_reg>;

[Severity: Critical]
Similar to the mali-supply removal above, does dropping the epod-supply 
property break the display subsystem power management on older kernels that 
rely on it?

[Severity: Low]
Additionally, is epod-supply still required by the display subsystem binding 
schema? Documentation/devicetree/bindings/display/ste,mcde.yaml seems to still 
mandate epod-supply in its required: block.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260618-ux500-power-domains-v7-1-v1-0-eb5e50b1a588@kernel.org?part=11