Messages in this thread | | | Date | Tue, 21 Nov 2023 08:33:15 +0100 | Subject | Re: [PATCH v2] docs: dt-bindings: add DTS Coding Style document | From | Michal Simek <> |
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On 11/20/23 20:31, Krzysztof Kozlowski wrote: > On 20/11/2023 20:18, Geert Uytterhoeven wrote: >> Hi Krzysztof, >> >> On Mon, Nov 20, 2023 at 3:53 PM Krzysztof Kozlowski >> <krzysztof.kozlowski@linaro.org> wrote: >>> On 20/11/2023 15:01, Michal Simek wrote:> > >>>> On 11/20/23 09:40, Krzysztof Kozlowski wrote: >>>>> Document preferred coding style for Devicetree sources (DTS and DTSI), >>>>> to bring consistency among all (sub)architectures and ease in reviews. >> >>>>> +Organizing DTSI and DTS >>>>> +----------------------- >>>>> + >>>>> +The DTSI and DTS files should be organized in a way representing the common >>>>> +(and re-usable) parts of the hardware. Typically this means organizing DTSI >>>>> +and DTS files into several files: >>>>> + >>>>> +1. DTSI with contents of the entire SoC (without nodes for hardware not present >>>>> + on the SoC). >>>>> +2. If applicable: DTSI with common or re-usable parts of the hardware (e.g. >>>>> + entire System-on-Module). >>>> >>>> DTS/DTSI - SOMs can actually run as they are that's why it is fair to say that >>>> there doesn't need to be DTS representing the board. >>> >>> I have never seen a SoM which can run without elaborate hardware-hacking >>> (e.g. connecting multiple wires to the SoM pins). The definition of the >>> SoM is that it is a module. Module can be re-used, just like SoC. >> >> /me looks at his board farm... >> >> The Renesas White-Hawk CPU board can be used standalone, and has a >> separate power input connector for this operation mode. As it has RAM, >> Ethernet, serial console, eMMC, and even mini-DP, it can serve useful >> purposes on its own. >> I agree it's not a super-good example, as the board is not really a >> "SoM", and we currently don't have r8a779g0-white-hawk-cpu.dts, only >> r8a779g0-white-hawk-cpu.dtsi. >> >> The RZ/A2M CPU Board is a real SoM, which can be powered over USB. >> It has less standard connectors (microSD, USB, MIPI CSI-2), but still >> sufficient features to be usable on its own. >> Again, we're doing a bad job, as we only have a DTS for the full eval >> board (r7s9210-rza2mevb.dts). >> >> I guess there are (many) other examples... > > OK, I never had such in my hands. Anyway, the SoM which can run > standalone has a meaning of a board, so how exactly you want to > rephrase the paragraph?
What about?
2. If applicable: DTSI with common or re-usable parts of the hardware (e.g. entire System-on-Module). DTS if runs standalone.
Thanks, Michal
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