Part Number: AM625
Other Parts Discussed in Thread: WL1837, SK-AM62
Board: AM62x SK-EVM (AM6254ATCGHAALW), custom Yocto (Kirkstone/4.0.35) build using meta-ti-bsp, linux-ti-staging 6.1.83.
Goal: Enable onboard WL1837 Bluetooth (HCI over UART) on main_uart1 (schematic label UART2), which is disabled by default in TI's k3-am625-sk.dts / k3-am62x-sk-common.dtsi.
What I've done:
- Added a Bluetooth child node under main_uart1 (serial@2810000) with compatible = "ti,wl1837-st" and max-speed = <3000000>, matching Documentation/devicetree/bindings/net/ti,bluetooth.yaml
- Forced main_uart1 status = "okay" with uart-has-rtscts
- Added GPIO hogs for UART1_FET_BUF_EN and UART1_FET_SEL (IO expander lines 10 and 21) to route the UART path, per schematic
- Installed bt-fw, uim-sysfs, wlconf, and TI BT init firmware (.bts files) in the rootfs
- Masked serial-getty@ttyS3 to free the UART
- Set hci_uart to autoload via modules-load.d
Current status: DTB confirms main_uart1 status = "okay", Bluetooth child node present with correct compatible string, no UART getty contention, and correct firmware files in /lib/firmware/ti-connectivity. However:
dmesg shows: "omap8250 2810000.serial: failed to get alias"
/proc/device-tree/aliases only exposes serial0/serial1/serial2 — no alias for main_uart1 (which should be serial3).
Because of this, hci_uart never binds a serdev instance to the UART, hciconfig -a returns no hci0, and rfkill only shows the WLAN radio, not Bluetooth.
Question:
1. Why does TI's k3-am62x-sk-common.dtsi aliases node not include main_uart1, unlike main_uart0-2?
2. Is adding "serial3 = &main_uart1;" to the aliases node in k3-am62x-sk-common.dtsi the correct/supported way to fix this, or is there a different recommended path (e.g., via chosen node, u-boot alias passthrough, or a different serdev binding) for enabling WL1837 BT on this specific EVM?
3. Is there a reference DTS/example anywhere in TI's tree showing WL1837 BT enablement on the SK-AM62 UART1 path? We could not find one.
Attaching: relevant DTS patch and dmesg/hciconfig output.
