Re: [PATCH] reset: thead: Scope TH1520 reset driver to VO subsystem

From: Drew Fustini
Date: Tue Aug 12 2025 - 01:43:14 EST


On Sun, Aug 10, 2025 at 11:14:19PM +0200, Michal Wilczynski wrote:
> The reset controller driver for the TH1520 was using the generic
> compatible string "thead,th1520-reset". However, the current
> implementation only manages the resets for the Video Output (VO)
> subsystem.

Looking at Section 5.4 on Page 451 of the TH1520 System User Manual [1],
it does seem like we would ultimately need 6 separate nodes for reset
controllers:

0xFF_EF01_4000: AP_SUBSYS
0xFF_EC02_C000: MISC_SUBSYS
0xFF_E404_0000: VI_SUBSYS
0xFF_EF52_8000: VO_SUBSYS
0xFF_ECC3_0000: VP_SUBSYS
0xFF_EF04_0000: DSP_SUBSYS

Maybe we should take this opportunity to document the bindings for all
the resets that the REE (e.g. Linux) can control?

It seemed like that was overkill for the 2 resets needed for the GPU,
but, as Krzysztof noted in this thread, problems arise when bindings are
introduced that are not complete.

Thanks,
Drew

[1] https://git.beagleboard.org/beaglev-ahead/beaglev-ahead/-/blob/main/docs/TH1520%20System%20User%20Manual.pdf