On 21/11/2023 11:13, Dmitry Baryshkov wrote: > On Tue, 21 Nov 2023 at 10:09, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote: >> >> Hi Krzysztof, >> >> On Tue, Nov 21, 2023 at 8:47 AM Krzysztof Kozlowski >> <krzysztof.kozlowski@xxxxxxxxxx> wrote: >>> On 21/11/2023 08:33, Michal Simek wrote: >>>> On 11/20/23 20:31, Krzysztof Kozlowski wrote: >>>>> On 20/11/2023 20:18, Geert Uytterhoeven wrote: >>>>>> On Mon, Nov 20, 2023 at 3:53 PM Krzysztof Kozlowski >>>>>> <krzysztof.kozlowski@xxxxxxxxxx> 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... >> >>>>>> 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. >>> >>> OK, but then it's duplicating the option 3. It also suggests that SoM >>> should be a DTS, which is not what we want for such case. Such SoMs must >>> have DTSI+DTS. >> >> So you want us to have a one-line <SoM>.dts, which just includes <SoM>.dtsi? > > Well, I think it is impossible to run SoM directly. There is a carrier > board anyway, which includes at least regulators. So, I guess, the > SoM.dts will not be a oneline file. Geert claims he has SoM with an USB connector which can run when power is supplied by that USB connector. I can imagine a CPU board (so a SoM in format of a board, not small DIMM-card) which has connectors e.g. for power and a slot for external motherboard for additional, optional interfaces. Look at picture on 14th page: https://www.renesas.com/us/en/document/mat/rza2m-cpu-board-users-manual This looks like some case of SoM, although maybe not that popular outside of Renesas :) Best regards, Krzysztof
