[PATCH v2 1/7] dt-bindings: clock: Document T-Head TH1520 AP_SUBSYS controller

[Drew Fustini]

On Fri, Jul 26, 2024 at 03:45:36AM -0500, Emil Renner Berthing wrote:
> Stephen Boyd wrote:
> > Quoting Drew Fustini (2024-06-23 19:12:31)
> > > Document bindings for the T-Head TH1520 AP sub-system clock controller.
> > >
> > > Link: https://openbeagle.org/beaglev-ahead/beaglev-ahead/-/blob/main/docs/TH1520%20System%20User%20Manual.pdf
> > > Co-developed-by: Yangtao Li <frank.li at vivo.com>
> > > Signed-off-by: Yangtao Li <frank.li at vivo.com>
> > > Reviewed-by: Conor Dooley <conor.dooley at microchip.com>
> > > Signed-off-by: Drew Fustini <dfustini at tenstorrent.com>
> > > ---
> >
> > Applied to clk-next
> 
> Thanks, but this driver seems a bit incomplete. With this applied the Lichee Pi
> 4A no longer boots without the clk_ignore_unused kernel parameter.
> 
> /Emil

Is this the case when you apply the dts patches from this series?

The dts patches won't go in until 6.12 so I don't think the presence of
the clk-th1520-ap.c itself in 6.11 would break existing systems.

That said, I have been using clk_ignore_unused. I had been thinking that
made sense because the full set of clock controller drivers like
AON_SUBSYS (always on), AUDIO_SUBSYS, DSP_SUBSYS, etc, are not present
yet in mainline. However, the T-Head vendor kernel does have drivers for
all those clock controllers and I was suprised to see that the vendor
kernel fails to boot when I just tested removing clk_ignore_unused.

As for clk-th1520-ap.c in mainline, I'll investigate further which clk
disables seem to causing the boot failure when using the dts from this
series. I suspect I may need to add nodes that will cause the necessary
clks to be enabled by their respective drivers.

Thanks,
Drew