[PATCH v2] dt-bindings: sifive: describe sifive-blocks versioning

From: Paul Walmsley
Date: Mon May 13 2019 - 17:54:33 EST

For IP blocks that are generated from the public, open-source
sifive-blocks repository, describe the version numbering policy
that its maintainers intend to use, upon request from Rob
Herring <robh@xxxxxxxxxx>.

Signed-off-by: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Signed-off-by: Paul Walmsley <paul@xxxxxxxxx>
Reviewed-by: Palmer Dabbelt <palmer@xxxxxxxxxx>
Cc: Rob Herring <robh+dt@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxx>
Cc: Megan Wachs <megan@xxxxxxxxxx>
Cc: Wesley Terpstra <wesley@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: devicetree@xxxxxxxxxxxxxxx
Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx

This second version updates the example URL, requested by
Rob Herring <robh+dt@xxxxxxxxxx>.

.../sifive/sifive-blocks-ip-versioning.txt | 38 +++++++++++++++++++
1 file changed, 38 insertions(+)
create mode 100644 Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt

diff --git a/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
new file mode 100644
index 000000000000..beaa3b64084e
--- /dev/null
+++ b/Documentation/devicetree/bindings/sifive/sifive-blocks-ip-versioning.txt
@@ -0,0 +1,38 @@
+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:
+IP block-specific DT compatible strings are contained within the HDL,
+in the form "sifive,<ip-block-name><integer version number>".
+An example is "sifive,uart0" from:
+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";