Enable PWM

I copied the config flags for defconfig from https://github.com/raspberrypi/linux/blob/50a6e5cf28a24e7f4192ad6f70f472eca2097cc6/arch/arm64/configs/bcm2711_defconfig#L1508-L1513,
and included the PWM overlays from https://github.com/raspberrypi/linux/tree/50a6e5cf28a24e7f4192ad6f70f472eca2097cc6/arch/arm/boot/dts/overlays.

Author: clupprich

config.txt

@@ -63,9 +63,11 @@ dtoverlay=ramoops
 # Enable the UART (/dev/ttyS0)
 enable_uart=1
 
+# Comment this in or modify to enable PWM
+# dtoverlay=pwm
+
 [cm4]
 # Raspberry Pi CM4-only settings
 
 # For the CM4 I/O board, USB is disabled by default. This enables it.
 dtoverlay=dwc2,dr_mode=host
-

fwup.conf

@@ -82,6 +82,15 @@ file-resource ov5647.dtbo {
 file-resource i2c-mux.dtbo {
     host-path = "${NERVES_SYSTEM}/images/rpi-firmware/overlays/i2c-mux.dtbo"
 }
+file-resource pwm-2chan.dtbo {
+    host-path = "${NERVES_SYSTEM}/images/rpi-firmware/overlays/pwm-2chan.dtbo"
+}
+file-resource pwm.dtbo {
+    host-path = "${NERVES_SYSTEM}/images/rpi-firmware/overlays/pwm.dtbo"
+}
+file-resource pwm1.dtbo {
+    host-path = "${NERVES_SYSTEM}/images/rpi-firmware/overlays/pwm1.dtbo"
+}
 
 file-resource rootfs.img {
     host-path = ${ROOTFS}
@@ -197,6 +206,9 @@ task complete {
     on-resource imx708.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/imx708.dtbo") }
     on-resource ov5647.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/ov5647.dtbo") }
     on-resource i2c-mux.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/i2c-mux.dtbo") }
+    on-resource pwm-2chan.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/pwm-2chan.dtbo") }
+    on-resource pwm.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/pwm.dtbo") }
+    on-resource pwm1.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/pwm1.dtbo") }
 
     on-resource rootfs.img {
         # write to the first rootfs partition
@@ -274,6 +286,9 @@ task upgrade.a {
     on-resource imx708.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/imx708.dtbo") }
     on-resource ov5647.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/ov5647.dtbo") }
     on-resource i2c-mux.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/i2c-mux.dtbo") }
+    on-resource pwm-2chan.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/pwm-2chan.dtbo") }
+    on-resource pwm.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/pwm.dtbo") }
+    on-resource pwm1.dtbo { fat_write(${BOOT_A_PART_OFFSET}, "overlays/pwm1.dtbo") }
 
     on-resource rootfs.img {
         delta-source-raw-offset=${ROOTFS_B_PART_OFFSET}
@@ -359,6 +374,9 @@ task upgrade.b {
     on-resource imx708.dtbo { fat_write(${BOOT_B_PART_OFFSET}, "overlays/imx708.dtbo") }
     on-resource ov5647.dtbo { fat_write(${BOOT_B_PART_OFFSET}, "overlays/ov5647.dtbo") }
     on-resource i2c-mux.dtbo { fat_write(${BOOT_B_PART_OFFSET}, "overlays/i2c-mux.dtbo") }
+    on-resource pwm-2chan.dtbo { fat_write(${BOOT_B_PART_OFFSET}, "overlays/pwm-2chan.dtbo") }
+    on-resource pwm.dtbo { fat_write(${BOOT_B_PART_OFFSET}, "overlays/pwm.dtbo") }
+    on-resource pwm1.dtbo { fat_write(${BOOT_B_PART_OFFSET}, "overlays/pwm1.dtbo") }
 
     on-resource rootfs.img {
         delta-source-raw-offset=${ROOTFS_A_PART_OFFSET}

linux-6.6.defconfig

@@ -387,6 +387,9 @@ CONFIG_MAILBOX=y
 CONFIG_BCM2835_MBOX=y
 # CONFIG_IOMMU_SUPPORT is not set
 CONFIG_RASPBERRYPI_POWER=y
+CONFIG_PWM=y
+CONFIG_PWM_BCM2835=m
+CONFIG_PWM_RASPBERRYPI_POE=m
 CONFIG_GENERIC_PHY=y
 CONFIG_NVMEM_RMEM=y
 CONFIG_F2FS_FS=y