Re: [PATCH v2 1/7] clk: meson: mpll: properly handle spread spectrum

[Martin Blumenstingl]

On Mon, May 13, 2019 at 2:31 PM Jerome Brunet <jbrunet@xxxxxxxxxxxx> wrote:
>
> The bit 'SSEN' available on some MPLL DSS outputs is not related to the
> fractional part of the divider but to the function called
> 'Spread Spectrum'.
>
> This function might be used to solve EM issues by adding a jitter on
> clock signal. This widens the signal spectrum and weakens the peaks in it.
>
> While spread spectrum might be useful for some application, it is
> problematic for others, such as audio.
>
> This patch introduce a new flag to the MPLL driver to enable (or not) the
> spread spectrum function.
>
> Fixes: 1f737ffa13ef ("clk: meson: mpll: fix mpll0 fractional part ignored")
> Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
in v1 [0] I checked that Ethernet is still working on my Odroid-C1.
I didn't repeat this test with v2 but since the logic has not changed
you can still add my:
Tested-by: Martin Blumenstingl<martin.blumenstingl@xxxxxxxxxxxxxx>


[0] https://patchwork.kernel.org/patch/10877431/