When it comes to ordering of the individual properties inside each property group, applying natural sort order to multi-digit numbers [1] found inside the property names can result in more logical and more usable property lists, similarly to what's already the case with the alpha-numerical ordering of the nodes without unit addresses. Let's have this clearly specified in the DTS coding style, together with a brief description of the natural sort order for those readers who aren't familiar with it already. Also expand the provided node example a bit, to actually show the results of applying natural sort order. Applying strict alpha-numerical ordering can result in property lists that are suboptimal from the usability standpoint. For the provided example, which stems from a real-world DT, [2][3][4] applying strict alpha-numerical ordering produces the following undesirable result: vdd-0v9-supply = <&board_vreg1>; vdd-12v-supply = <&board_vreg3>; vdd-1v8-supply = <&board_vreg4>; vdd-3v3-supply = <&board_vreg2>; Having the properties sorted in natural order by their associated voltages is more logical, more usable, and a bit more consistent. [1] https://en.wikipedia.org/wiki/Natural_sort_order [2] https://lore.kernel.org/linux-rockchip/b39cfd7490d8194f053bf3971f13a43472d1769e.1740941097.git.dsimic@xxxxxxxxxxx/ [3] https://lore.kernel.org/linux-rockchip/174104113599.8946.16805724674396090918.b4-ty@xxxxxxxxx/ [4] https://lore.kernel.org/linux-rockchip/757afa87255212dfa5abf4c0e31deb08@xxxxxxxxxxx/ Signed-off-by: Dragan Simic <dsimic@xxxxxxxxxxx> --- Notes: Changes in v3: - Rewrote the part of the changes that describes natural sort order and its relation to "standard" alpha-numerical ordering, to make it more understandable, as suggested by Krzysztof [6] - Slightly expanded the patch description, to clarify the additional goal of explaining the natural sort order briefly Changes in v2: - Changed the additions to the coding style to specify natural sort order, which avoids amibguity, as suggested by Krzysztof [5] - Adjusted and expanded the patch description appropriately, together with including one more reference for the natural sort order Link to v1: https://lore.kernel.org/linux-kernel/09d6f2fc111b3d6e58987336944f93ec36b65118.1741071107.git.dsimic@xxxxxxxxxxx/T/#u Link to v2: https://lore.kernel.org/linux-kernel/47c51c10098f089e52fb14c5c5527611dc8daf32.1741164239.git.dsimic@xxxxxxxxxxx/T/#u [5] https://lore.kernel.org/linux-kernel/20250305-defiant-serious-newt-b7c5ea@krzk-bin/ [6] https://lore.kernel.org/linux-kernel/20250306-dexterous-goshawk-of-aptitude-e4f1f6@krzk-bin/ .../devicetree/bindings/dts-coding-style.rst | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/dts-coding-style.rst b/Documentation/devicetree/bindings/dts-coding-style.rst index 8a68331075a0..7d183c1ade74 100644 --- a/Documentation/devicetree/bindings/dts-coding-style.rst +++ b/Documentation/devicetree/bindings/dts-coding-style.rst @@ -133,6 +133,15 @@ The above-described ordering follows this approach: 3. Status is the last information to annotate that device node is or is not finished (board resources are needed). +The above-described ordering specifies the preferred ordering of property +groups, while the individual properties inside each group shall use natural +sort order by the property name. + +The natural sort order differs from alpha-numerical ordering only by treating +any single- and multi-digit numbers found inside the property names atomically, +and by taking their actual numerical values and comparing those values between +themselves to determine the order of property names. + Example:: /* SoC DTSI */ @@ -158,7 +167,10 @@ Example:: /* Board DTS */ &device_node { - vdd-supply = <&board_vreg1>; + vdd-0v9-supply = <&board_vreg1>; + vdd-1v8-supply = <&board_vreg4>; + vdd-3v3-supply = <&board_vreg2>; + vdd-12v-supply = <&board_vreg3>; status = "okay"; }
