Re: [PATCH v3] clk: sunxi-ng: sun50i: h6: Modify GPU clock configuration to support DFS

Jernej Škrabec
2022-07-08T16:15:34Z

Dne torek, 05. julij 2022 ob 09:52:26 CEST je Roman Stratiienko napisal(a):
> Using simple bash script it was discovered that not all CCU registers
> can be safely used for DFS, e.g.:
>
> while true
> do
> devmem 0x3001030 4 0xb0003e02
> devmem 0x3001030 4 0xb0001e02
> done
>
> Script above changes the GPU_PLL multiplier register value. While the
> script is running, the user should interact with the user interface.
>
> Using this method the following results were obtained:
> | Register | Name | Bits | Values | Result |
> | -- | -- | -- | -- | -- |
> | 0x3001030 | GPU_PLL.MULT | 15..8 | 20-62 | OK |
> | 0x3001030 | GPU_PLL.INDIV | 1 | 0-1 | OK |
> | 0x3001030 | GPU_PLL.OUTDIV | 0 | 0-1 | FAIL |
> | 0x3001670 | GPU_CLK.DIV | 3..0 | ANY | FAIL |
>
> DVFS started to work seamlessly once dividers which caused the
> glitches were set to fixed values.
>
> Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
>

Applied, thanks!

Best regards,
Jernej