Re: Raspberry Pi 3B: Failed to create device link with soc:firmware:gpio

[Martin Wetterwald]

On Thu, Dec 12, 2024 at 2:16 PM Stefan Wahren <wahrenst@xxxxxxx> wrote:
> What happens if you replace your custom config with arm64/defconfig?
> Does the issue still occurs?

I've just launched a kernel with the arm64 defconfig:

> 3f201000.serial: ttyAMA0 at MMIO 0x3f201000 (irq = 99, base_baud = 0) is a PL011 rev2
> serial serial0: tty port ttyAMA0 registered
> raspberrypi-firmware soc:firmware: Attached to firmware from 2024-09-13T16:00:01
> hci_uart_bcm serial0-0: supply vbat not found, using dummy regulator
> hci_uart_bcm serial0-0: supply vddio not found, using dummy regulator
> Bluetooth: hci0: BCM: chip id 94
> Bluetooth: hci0: BCM: features 0x2e
> Bluetooth: hci0: BCM43430A1
> Bluetooth: hci0: BCM43430A1 (001.002.009) build 0000

And it worked perfectly. Thanks for your suggestion. It confirmed the problem
came from my kernel config.

I then compared both .config and it appeared I was missing this config flag:

> CONFIG_SERIAL_DEV_CTRL_TTYPORT

I had already enabled CONFIG_SERIAL_DEV_BUS, but not CTRL_TTYPORT.
Nevertheless, that first kernel config item's prompt had been clear about that,
but I missed the advice:

> CONFIG_SERIAL_DEV_BUS
> Core support for devices connected via a serial port.
> Note that you typically also want to enable TTY port controller support.

It's so much better now to see the HCI attachment handled by the kernel
directly!

Thank you for your help.
Martin