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@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?
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
