Re: [PATCH 1/2] ARM: dts: aspeed: bletchley: Add second source ISL1208 RTC

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The new `rtc@6f` node is deliberately inserted out of numerical order (before `rtc@51`) to manipulate probe order. This acts as a brittle workaround for a driver bug in `rtc-pcf85363.c` (which unconditionally registers a phantom RTC even when the hardware is absent).
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--- Patch [1]: [PATCH 1/2] ARM: dts: aspeed: bletchley: Add second source ISL1208 RTC ---
commit e443fe47105505ac961ac3a866a76ec1173a5817
Author: Cosmo Chou <chou.cosmo@gmail.com>

ARM: dts: aspeed: bletchley: Add second source ISL1208 RTC

This commit adds an alternative ISL1208 RTC at address 0x6f to support
boards populated with it instead of the primary PCF85263 at 0x51.

> diff --git a/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-bletchley.dts b/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-bletchley.dts
> index d1a04b63df9e0..a966be69ff27d 100644
> --- a/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-bletchley.dts
> +++ b/arch/arm/boot/dts/aspeed/aspeed-bmc-facebook-bletchley.dts
> @@ -865,6 +865,11 @@ eeprom@56 {
>  		reg = <0x56>;
>  	};
>  
> +	rtc@6f {
> +		compatible = "isil,isl1208";
> +		reg = <0x6f>;
> +	};
> +
>  	rtc@51 {

[Severity: Medium]
Are these device tree nodes intentionally placed out of numerical order?

Typically, device tree nodes are sorted by their unit address, meaning rtc@51
would normally appear before rtc@6f.

If this out-of-order placement is intended to force rtc@6f to probe first
as a workaround for a driver issue in rtc-pcf85363.c (which unconditionally
registers a phantom RTC even when the hardware is absent), could this create
a brittle dependency?

If a developer later sorts these nodes by unit address during a routine
cleanup, the probe order would change. This could allow the phantom PCF85263
device to probe first and claim /dev/rtc0, which might silently break system
timekeeping on ISL1208 boards.

>  		/* in-chip rtc disabled, use external rtc (battery-backed) */
>  		compatible = "nxp,pcf85263";

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Sashiko AI review · https://sashiko.dev/#/patchset/20260714120816.1504058-1-chou.cosmo@gmail.com?part=1