@@ -81,6 +81,24 @@ dtb-$(CONFIG_SOC_SAMA7G5) += \
at91-sama7g5ek.dtb
dtb-$(CONFIG_ARCH_AXXIA) += \
axm5516-amarillo.dtb
+# Enables support for device-tree overlays
+DTC_FLAGS_bcm2835-rpi-b := -@
+DTC_FLAGS_bcm2835-rpi-a := -@
+DTC_FLAGS_bcm2835-rpi-b-rev2 := -@
+DTC_FLAGS_bcm2835-rpi-b-plus := -@
+DTC_FLAGS_bcm2835-rpi-a-plus := -@
+DTC_FLAGS_bcm2835-rpi-cm1-io1 := -@
+DTC_FLAGS_bcm2836-rpi-2-b := -@
+DTC_FLAGS_bcm2837-rpi-3-a-plus := -@
+DTC_FLAGS_bcm2837-rpi-3-b := -@
+DTC_FLAGS_bcm2837-rpi-3-b-plus := -@
+DTC_FLAGS_bcm2837-rpi-cm3-io3 := -@
+DTC_FLAGS_bcm2837-rpi-zero-2-w := -@
+DTC_FLAGS_bcm2711-rpi-400 := -@
+DTC_FLAGS_bcm2711-rpi-4-b := -@
+DTC_FLAGS_bcm2711-rpi-cm4-io := -@
+DTC_FLAGS_bcm2835-rpi-zero := -@
+DTC_FLAGS_bcm2835-rpi-zero-w := -@
dtb-$(CONFIG_ARCH_BCM2835) += \
bcm2835-rpi-b.dtb \
bcm2835-rpi-a.dtb \
Add the '-@' DTC option for the Raspberry Pi devices. This option populates the '__symbols__' node that contains all the necessary symbols for supporting device-tree overlays (for instance from the firmware or the bootloader) on these devices. The Rasbperry Pi devices are well known for their GPIO header, that allow various "HATs" or other modules do be connected and this enables users to create out-of-tree device-tree overlays for these modules. Please note that this change does increase the size of the resulting DTB by ~40%. For example, with v5.17 increase in size is as follows: bcm2711-rpi-400.dtb 26481 -> 36830 bytes bcm2711-rpi-4-b.dtb 26537 -> 36886 bytes bcm2711-rpi-cm4-io.dtb 26426 -> 36945 bytes bcm2835-rpi-a.dtb 12641 -> 17852 bytes bcm2835-rpi-a-plus.dtb 12765 -> 17976 bytes bcm2835-rpi-b.dtb 12763 -> 17998 bytes bcm2835-rpi-b-plus.dtb 12979 -> 18263 bytes bcm2835-rpi-b-rev2.dtb 12847 -> 18131 bytes bcm2835-rpi-cm1-io1.dtb 12839 -> 18113 bytes bcm2835-rpi-zero.dtb 12681 -> 17924 bytes bcm2835-rpi-zero-w.dtb 13135 -> 18430 bytes bcm2836-rpi-2-b.dtb 13687 -> 19255 bytes bcm2837-rpi-3-a-plus.dtb 14133 -> 19740 bytes bcm2837-rpi-3-b.dtb 14310 -> 20006 bytes bcm2837-rpi-3-b-plus.dtb 14670 -> 20474 bytes bcm2837-rpi-cm3-io3.dtb 13680 -> 19266 bytes Signed-off-by: Aurelien Jarno <aurelien@aurel32.net> --- arch/arm/boot/dts/Makefile | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+)