[PATCH] arm64: imx8mp: Inhibit DTC warning on DH i.MX8MP DHCOM rev.100 DTO

[Marek Vasut]

Inhibit DTC warning in imx8mp-dhcom-pdk3-overlay-rev100.dts:
"
arch/arm/dts/imx8mp-dhcom-pdk3-overlay-rev100.dtbo: Warning (reg_format): /fragment at 0/__overlay__:reg: property has invalid length (4 bytes) (#address-cells == 2, #size-cells == 1)
arch/arm/dts/imx8mp-dhcom-pdk3-overlay-rev100.dtbo: Warning (avoid_default_addr_size): /fragment at 0/__overlay__: Relying on default #address-cells value
arch/arm/dts/imx8mp-dhcom-pdk3-overlay-rev100.dtbo: Warning (avoid_default_addr_size): /fragment at 0/__overlay__: Relying on default #size-cells value
"

The DTO overwrites the 'reg' property of an ethernet PHY and is only
used on specific combination of old prototype SoM and old prototype
PDK3 carrier board, which had incorrectly placed pull resistor, which
made the PHY change its MDIO address in that specific combination and
which is already fixed on production hardware.

The DTO is implemented in this simple manner because if it contained a
full MDIO bus node reference to define #address-cells and #size-cells,
it would also require a full new copy of the PHY node, i.e.
ethernet-phy at 5 { ... reg = <5>; ... }, to avoid DTC warnings about
mismatch between node unit and reg value. The node unit in SoM DT is
ethernet-phy at 7 { ... }; .

This simpler approach avoids unnecessary duplication without adverse
side effects.

Reported-by: Fabio Estevam <festevam at denx.de>
Reported-by: Sean Anderson <seanga2 at gmail.com>
Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: "NXP i.MX U-Boot Team" <uboot-imx at nxp.com>
Cc: Andreas Geisreiter <ageisreiter at dh-electronics.de>
Cc: Christoph Niedermaier <cniedermaier at dh-electronics.com>
Cc: Fabio Estevam <festevam at gmail.com>
Cc: Stefano Babic <sbabic at denx.de>
Cc: u-boot at dh-electronics.com
---
 arch/arm/dts/Makefile | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 66862a70be1..70845c7ac8c 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -1481,6 +1481,8 @@ targets += $(dtb-y)
 # Add any required device tree compiler flags here
 DTC_FLAGS += -a 0x8
 
+DTC_FLAGS_imx8mp-dhcom-pdk3-overlay-rev100 += -Wno-avoid_default_addr_size -Wno-reg_format
+
 PHONY += dtbs
 dtbs: $(addprefix $(obj)/, $(dtb-y))
 	@:
-- 
2.42.0