Re: [PATCH v4 5/5] clk: rockchip: rk3588: add GATE_GRF clocks for I2S MCLK output to IO

[Diederik de Haas]

On Tue Jun 23, 2026 at 2:33 PM CEST, Daniele Briguglio wrote:
>> can you check if adding CLK_IGNORE_UNUSED changes the situation for you?
>> What I assume is happening is that when the clocks were not declared they were
>> just left running, while now the kernel turns off unused (but defined) clocks.
>
> That lines up with what I see. The gates are set-to-disable and reset to
> open, so before the series the bit just kept whatever the boot firmware
> left it at.
>
> Diederik, the cleanest way to confirm is to read SOC_CON6 before Linux
> touches it, e.g. md.l 0xfd58c318 at the U-Boot prompt (bit 0 is I2S0). If
> it comes up clear there, the gate is open, and if audio then breaks once
> the kernel is up, that points at clk_disable_unused turning it off because
> nothing references it.

NanoPC-T6 LTS
U-Boot: 2026.04-00003-g723f0da896bc

The 0003 comes from me adding patches for NanoPC-T6 Plus support, but
otherwise it's plain upstream U-Boot.

=> md.l 0xfd58c318
fd58c318: 00000600 00000a00 00000000 00000000  ................
fd58c328: 00000300 00092820 0fd58c338: 00000000 00000000 00000000 00000000  ................
fd58c348: 00000000 00000000 00000000 00000000  ................c358: 00000000 00000000 00000000 00000000  ................
fd58c368: 00000000 00000000 00000008: 00000000 00000000 00001000 00000240  ............@...
fd58c388: 0000003f 0000fefe 00000000 000000000 00000000 00000000 00000000  ................
fd58c3a8: 00000000 00000000 00000000 00000000 00000000 00000000 00000000  ................
fd58c3c8: 00000000 00000000 00000000 000000000 00000000 00000000 00000000  ................
fd58c3e8: 00000000 00000000 00000000 00000000  .0000000 00000000 00000000  ................
fd58c408: 00000000 00000000 00000000 00000000  ....

I'll let interpreting it up to you.

> If that turns out to be the case, CLK_IGNORE_UNUSED on the gates is a
> reasonable way to stop the kernel from closing a gate the firmware already
> left open, for boards that would rather not switch their DTS to _TO_IO.

I'm not so sure I agree that CLK_IGNORE_UNUSED is reasonable, but I'll leave
judgement up to others. I'll do the test regardless, though.

Cheers,
  Diederik

> Where a board does reference _TO_IO the consumer holds it open anyway, so
> that path is unaffected either way.
>
> Best regards,
> Daniele