On 20/11/2023 20:18, Geert Uytterhoeven wrote: > Hi Krzysztof, > > 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... > > 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? Best regards, Krzysztof
