[Letux-kernel] jz4780 and cpufreq-info

[H. Nikolaus Schaller]

Hi Paul and Riccardo,
just a small note about CI20 progress.

I have managed to have WIFI work with LetuxOS. And fixed the reboot issue.
But Bluetooth needs a workaround to start at all and then the receiver is deaf.

But I also have prepared a patch set for upstreaming and there it is reversed:
WLAN is missing in ifconfig, but Bluetooth works.

What I have found out so far is that it is a mix between different defconfig
and DTS. All Bluetooth components must be compiled into the kernel while the
pcf8563 must not be available.

The reason is simple: the pcf8563 driver disables the 32kHz clock for a moment
during probe - but at that point Bluetooth has already been initialized. This
makes the BT HCI engine stall.

What I have not yet found out is how to make the jz4780 clock-out request the
pcf8563 clock-out and make both a precondition for Bluetooth and WiFi power.
This is the DTS related part. Basically it should be simple because clock providers
form a chain to be probed and enabled, but I do not know how to add a request
for the clock-outs to this chain.

BTW: by having the BT stack being initialized very early in the boot sequence
makes loading the firmware patches fail, because there is no MMC and rootfs
available to load it from. But BT works without them in the upstream variant.

I don't know how fast I can work on this, but the next letux-6.2-rc kernel
release should have WLAN and reboot working (even if not perfect).

Best Regards,
Nikolaus