arm64: dts: broadcom: amend the comment about the role of BCM2712 board DTS

Current board DTS for Raspberry Pi5 states that bcm2712-rpi-5-b.dts
should not be modified and all declarations should go in the overlay
board DTS instead (bcm2712-rpi-5-b-ovl-rp1.dts).

There's a caveat though: there's currently no infrastructure to reliably
reference nodes that have not been declared yet, as is the case when
loading those nodes from a runtime overlay. For more details about
these limitations see [1] and follow-ups.

Change the comment to make it clear which DTS file will host specific
nodes, especially the RP1 related nodes which should be customized
outside the overlay DTS.

Link
[1] - https://lore.kernel.org/all/CAMEGJJ3=W8_R0xBvm8r+Q7iExZx8xPBHEWWGAT9ngpGWDSKCaQ@mail.gmail.com/

Signed-off-by: Andrea della Porta <andrea.porta@suse.com>
Link: https://lore.kernel.org/r/47f6368a77d6bd846c02942d20c07dd48e0ae7df.1754914766.git.andrea.porta@suse.com
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>

diff --git a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
index 55dbacf5a6fc9955ce5854a3755d494c90479046..2045a221c39305b9fe570e716ba13c7c4864487a 100644 (file)
--- a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
+++ b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
@@ -4,8 +4,14 @@
  * the RP1 driver to load the RP1 dtb overlay at runtime, while
  * bcm2712-rpi-5-b.dts (this file) is the fully defined one (i.e. it
  * already contains RP1 node, so no overlay is loaded nor needed).
- * This file is not intended to be modified, nodes should be added
- * to the included bcm2712-rpi-5-b-ovl-rp1.dts.
+ * This file is intended to host the override nodes for the RP1 peripherals,
+ * e.g. to declare the phy of the ethernet interface or the custom pin setup
+ * for several RP1 peripherals.
+ * This in turn is due to the fact that there's no current generic
+ * infrastructure to reference nodes (i.e. the nodes in rp1-common.dtsi) that
+ * are not yet defined in the DT since they are loaded at runtime via overlay.
+ * All other nodes that do not have anything to do with RP1 should be added
+ * to the included bcm2712-rpi-5-b-ovl-rp1.dts instead.
  */
 
 /dts-v1/;