DT compatible string versioning for SiFive open-source IP blocks This document describes the version specification for DT "compatible" strings for open-source SiFive IP blocks. HDL for these IP blocks can be found in this public repository: https://github.com/sifive/sifive-blocks IP block-specific DT compatible strings are contained within the HDL, in the form "sifive,". An example is "sifive,uart0" from: https://github.com/sifive/sifive-blocks/blob/v1.0/src/main/scala/devices/uart/UART.scala#L43 Until these IP blocks (or IP integration) support version auto-discovery, the maintainers of these IP blocks intend to increment the suffixed number in the compatible string whenever the software interface to these IP blocks changes, or when the functionality of the underlying IP blocks changes in a way that software should be aware of. Driver developers can use compatible string "match" values such as "sifive,uart0" to indicate that their driver is compatible with the register interface and functionality associated with the relevant upstream sifive-blocks commits. It is expected that most drivers will match on these IP block-specific compatible strings. DT data authors, when writing data for a particular SoC, should continue to specify an SoC-specific compatible string value, such as "sifive,fu540-c000-uart". This way, if SoC-specific integration-specific bug fixes or workarounds are needed, the kernel or other system software can match on this string to apply them. The IP block-specific compatible string (such as "sifive,uart0") should then be specified as a subsequent value. An example of this style: compatible = "sifive,fu540-c000-uart", "sifive,uart0";