arm64: dts: sc598-ezkit: Add boot-trace label to gpio

[CalebEthridgeADI]

PR Description

Add a label to the gpio on pin 13 of port A so that scripts can use the label instead of hardcoding port + pin.

PR Type

• Bug fix (a change that fixes an issue)
• New feature (a change that adds new functionality)
• Breaking change (a change that affects other repos or cause CIs to fail)

PR Checklist

• I have conducted a self-review of my own code changes
• I have compiled my changes, including the documentation
• I have tested the changes on the relevant hardware
• I have updated the documentation outside this repo accordingly
• I have provided links for the relevant upstream lore

[pamolloy]

These gpios are all routed onto the carrier board? Is there a generic label on the silk screen we can use? Is this routed to a header, test point, or some peripheral?

[CalebEthridgeADI]

This is routed to the carrier to a header marked "SIGMA STUDIO" which is currently not used in the device tree. PA10-15 are routed to this header, the others are not as PA0-9 have other functions that are used like UART0 and the OSPI.

[github-actions]

LLM review

This series adds a gpio-line-names entry to the SC598 EZ-Kit DTS, labeling PA13 as "boot-trace" so userspace scripts can reference it by name instead of hard-coding port and pin numbers.

run: 28792818881

5ef57bc74069 - arm64: dts: sc598-ezkit: Add boot-trace label to gpio

The change is correct. The gpio-line-names array has 14 entries for a 16-line GPIO controller (gpa, gpio-ranges = <&pinctrl0 0 0 16>). An incomplete array is explicitly permitted by Documentation/devicetree/bindings/gpio/gpio.txt:

"An incomplete array (where the number of passed names is less than ngpios) will be used up until the last provided valid line index."

"boot-trace" lands at index 13 (PA13), which is correct. The name is functional and follows DT naming guidelines. checkpatch.pl reports 0 errors, 0 warnings.

CI warnings

All CI warnings (simple_bus_reg, unique_unit_address, unit_address_vs_reg) originate from arch/arm64/boot/dts/adi/sc598-som.dtsi, which is not modified by this series. They are pre-existing issues unrelated to this patch.

Verification data

• Built sc598-som-ezkit.dtb with make sc598-som-ezkit_defconfig + make dtbs (gcc_aarch64): no new errors or warnings.
• Parsed the compiled DTB with pylibfdt and confirmed /scb/gport@31004000 contains gpio-line-names = ['', '', '', '', '', '', '', '', '', '', '', '', '', 'boot-trace'] with boot-trace at index 13.
• Ran dtbs_check with the gpio schema: no gpio-line-names violations.

[nunojsa]

Assuming there's no other meaningful labels to set