Dependency: ACPI - Define AML device for SPCR type 0x12 devices

[andreiw]

Type 0x12 can describe NS16550-like UARTs that cannot be described by PNP0501 - the e.g. register stride, clock frequency. And there are other "tunables" which may be interesting to the OS driver. This should have it's own ACPIxxxx _CID.

Can model this on https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/serial/8250.yaml.

These seem like a good set. Should these use DSD DT?

• clock-frequency
• reg-offset
• reg-shift
• reg-io-width
• fifo-size

[adurbin-rivos]

'DSD DT' - what do you mean by this? device specific data and have that under a specific ACPIxxxx device name?

[paul-walmsley-sifive]

'DSD DT' - what do you mean by this? device specific data and have that under a specific ACPIxxxx device name?

He's probably referring to the practice of embedding DT properties into the _DSD entries, i.e., https://docs.kernel.org/6.2/firmware-guide/acpi/dsd/graph.html

[adurbin-rivos]

Yes, that was my question confirming if DSD DT meant that. I assumed so, but I wanted to be sure.

[andreiw]

Yes, Paul is correct.

[andreiw]

This would be nice to have but ideally is code-first and fueled by someone who needs it

[andreiw]

reg-offset is not necessary (there's nothing matching that in SPCR)

[andreiw]

Also need to add the rscv- Known Device Property Prefixex