Re: [PATCH] clk: sunxi-ng: v3s: add support for variable rate audio pll output

From: Icenowy Zheng
Date: Thu Feb 18 2021 - 04:21:38 EST




于 2021年2月18日 GMT+08:00 下午3:58:35, Maxime Ripard <maxime@xxxxxxxxxx> 写到:
>Hi,
>
>On Fri, Feb 12, 2021 at 02:57:25PM +0100, Tobias Schramm wrote:
>> Previously the variable rate audio pll output was fixed to a divider
>of
>> four. This is unfortunately incompatible with generating commonly
>used
>> I2S core clock rates like 24.576MHz from the 24MHz parent clock.
>> This commit adds support for arbitrary audio pll output dividers to
>fix
>> that.
>>
>> Signed-off-by: Tobias Schramm <t.schramm@xxxxxxxxxxx>
>
>It's not really clear to me how that would help.

We have introducee SDM-based accurate audio PLL on several
other SoCs. Some people is quite sensitive about audio-related things.

>
>The closest frequency we can provide for 24.576MHz would be 24580645
>Hz,
>with N = 127, M = 31 and P = 4, so it would work with what we have
>already?
>
>Maxime