Re: [PATCH v1 5/9] arm64: dts: agilex5: add SOCDK eMMC daughter board support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] The `no-1-8-v` property in the `&emmc` node explicitly disables the 1.8V HS200 and HS400 modes, contradicting the commit intent.
- [Medium] A board-specific fixed regulator (`emmc_io_1v8_reg`) is improperly defined in the shared SoC-level `.dtsi` file and placed under a memory-mapped bus.
--

commit 832d2f01748902348b5ee8ddc2a87d8dfab30896
Author: Tanmay Kathpalia <tanmay.kathpalia@altera.com>

arm64: dts: agilex5: add SOCDK eMMC daughter board support

This commit adds device tree support for the Agilex5 SOCDK eMMC daughter
board. It introduces the new board dts file and adds a fixed 1.8V regulator
for the eMMC I/O voltage to the common SoC dtsi.

> diff --git a/arch/arm64/boot/dts/intel/socfpga_agilex5.dtsi b/arch/arm64/boot/dts/intel/socfpga_agilex5.dtsi
> index 7e080f13166f2..feb4ccb317a71 100644
> --- a/arch/arm64/boot/dts/intel/socfpga_agilex5.dtsi
> +++ b/arch/arm64/boot/dts/intel/socfpga_agilex5.dtsi
[ ... ]
> @@ -317,6 +317,14 @@ sd_io_1v8_reg: regulator-1p8v {
>  					<3300000 0x0>;
>  		};
>  
> +		emmc_io_1v8_reg: regulator-fixed-1p8v {
> +			compatible = "regulator-fixed";
> +			regulator-name = "emmc-io-power";
> +			regulator-min-microvolt = <1800000>;
> +			regulator-max-microvolt = <1800000>;
> +			regulator-always-on;
> +		};
> +

Will this cause every Agilex 5 board to inadvertently instantiate and enable
this regulator, even if they do not have the eMMC daughter card attached?
Since this appears to be a board-specific regulator, would it be better
placed at the root level of the board-specific socfpga_agilex5_socdk_emmc.dts
file?

Additionally, does placing this node inside a memory-mapped bus without a reg
property trigger device tree compiler warnings?

> diff --git a/arch/arm64/boot/dts/intel/socfpga_agilex5_socdk_emmc.dts b/arch/arm64/boot/dts/intel/socfpga_agilex5_socdk_emmc.dts
> new file mode 100644
> index 0000000000000..87bde9fa69c6c
> --- /dev/null
> +++ b/arch/arm64/boot/dts/intel/socfpga_agilex5_socdk_emmc.dts
[ ... ]
> +&emmc {
> +	status = "okay";
> +
> +	no-sd;
> +	no-sdio;
> +	no-1-8-v;

The commit message states the eMMC controller is configured for HS200 and
HS400 modes at 1.8V. Does the no-1-8-v property prevent these high-speed
modes from functioning?

In the SDHCI core, parsing no-1-8-v sets the SDHCI_QUIRK2_NO_1_8_V flag,
which strips out the MMC_CAP2_HSX00_1_8V and MMC_CAP2_HS400_ES capabilities
during host setup. Since the eMMC IO is explicitly supplied by a 1.8V
regulator, shouldn't this property be removed to allow HS200 and HS400
negotiation?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260511202132.5597-1-tanmay.kathpalia@altera.com?part=5