From: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
To: Jerome Brunet <jbrunet@baylibre.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>,
Stephen Boyd <sboyd@kernel.org>,
Kevin Hilman <khilman@baylibre.com>,
Michael Turquette <mturquette@baylibre.com>,
linux-kernel@vger.kernel.org, linux-amlogic@lists.infradead.org,
linux-clk@vger.kernel.org
Subject: Re: [PATCH v2 1/7] clk: meson: mpll: properly handle spread spectrum
Date: Tue, 14 May 2019 20:16:28 +0200 [thread overview]
Message-ID: <CAFBinCBOtsSCg40L+PovAwN2dvLpDO7KMhJpcftpSiv+moBDSA@mail.gmail.com> (raw)
In-Reply-To: <20190513123115.18145-2-jbrunet@baylibre.com>
On Mon, May 13, 2019 at 2:31 PM Jerome Brunet <jbrunet@baylibre.com> 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@baylibre.com>
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@googlemail.com>
[0] https://patchwork.kernel.org/patch/10877431/
_______________________________________________
linux-amlogic mailing list
linux-amlogic@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic
next prev parent reply other threads:[~2019-05-14 18:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-13 12:31 [PATCH v2 0/7] clk: meson: fix mpll jitter Jerome Brunet
2019-05-13 12:31 ` [PATCH v2 1/7] clk: meson: mpll: properly handle spread spectrum Jerome Brunet
2019-05-14 18:16 ` Martin Blumenstingl [this message]
2019-05-13 12:31 ` [PATCH v2 2/7] clk: meson: gxbb: no spread spectrum on mpll0 Jerome Brunet
2019-05-13 12:31 ` [PATCH v2 3/7] clk: meson: axg: spread spectrum is on mpll2 Jerome Brunet
2019-05-13 12:31 ` [PATCH v2 4/7] clk: meson: mpll: add init callback and regs Jerome Brunet
2019-05-13 12:31 ` [PATCH v2 5/7] clk: meson: g12a: add mpll register init sequences Jerome Brunet
2019-05-13 12:31 ` [PATCH v2 6/7] clk: meson: eeclk: add init regs Jerome Brunet
2019-05-13 12:31 ` [PATCH v2 7/7] clk: meson: g12a: add controller register init Jerome Brunet
2019-05-20 11:26 ` [PATCH v2 0/7] clk: meson: fix mpll jitter Jerome Brunet
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAFBinCBOtsSCg40L+PovAwN2dvLpDO7KMhJpcftpSiv+moBDSA@mail.gmail.com \
--to=martin.blumenstingl@googlemail.com \
--cc=jbrunet@baylibre.com \
--cc=khilman@baylibre.com \
--cc=linux-amlogic@lists.infradead.org \
--cc=linux-clk@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mturquette@baylibre.com \
--cc=narmstrong@baylibre.com \
--cc=sboyd@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).