From: Andrew Lunn <andrew@lunn.ch>
To: Florian Fainelli <f.fainelli@gmail.com>
Cc: Adrien Grassein <adrien.grassein@gmail.com>,
fugang.duan@nxp.com, davem@davemloft.net, kuba@kernel.org,
robh+dt@kernel.org, netdev@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/3] dt-bindings: net: fsl-fec add mdc/mdio bitbang option
Date: Mon, 30 Nov 2020 23:26:45 +0100 [thread overview]
Message-ID: <20201130222645.GG2073444@lunn.ch> (raw)
In-Reply-To: <bb81c90c-d79e-d944-e35e-305da23d9e58@gmail.com>
> >> I am currently upstreaming the "Nitrogen 8m Mini board" that seems to not use a
> >> "normal" mdio bus but a "bitbanged" one with the fsl fec driver.
> >
> > Any idea why?
> >
> > Anyway, you should not replicate code, don't copy bitbanging code into
> > the FEC. Just use the existing bit-banger MDIO bus master driver.
>
> Right there should be no need for you to modify the FEC driver at all,
> there is an existing generic bitbanged MDIO bus driver here:
Hi Florian
Speculation on my part, until i hear back on the Why? question, but
i'm guessing the board has a wrong pullup on the MDIO line. It takes
too long for the PHY/FEC to pull the line low at the default
2.5MHz. bit-banging is much slower, so it works.
If i'm right, there is a much simpler fix for this. Use the
clock-frequency property for the MDIO bus to slow the clock down.
Andrew
next prev parent reply other threads:[~2020-11-30 22:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-28 22:54 [PATCH 1/3] dt-bindings: net: fsl-fec add mdc/mdio bitbang option Adrien Grassein
2020-11-28 22:54 ` [PATCH 2/3] net: fsl: fec: " Adrien Grassein
2020-11-28 22:54 ` [PATCH 3/3] net: fsl: fec: add imx8mq support Adrien Grassein
2020-11-29 21:59 ` [PATCH v2 1/3] dt-bindings: net: fsl-fec add mdc/mdio bitbang option Adrien Grassein
2020-11-29 21:59 ` [PATCH v2 2/3] net: fsl: fec: " Adrien Grassein
2020-11-29 22:00 ` [PATCH v2 3/3] net: fsl: fec: add imx8mq support Adrien Grassein
[not found] ` <20201129224113.GS2234159@lunn.ch>
[not found] ` <CABkfQAFcSNMeYEepsx0Z6tuaif-dQhE2YBMK54t1hikAvzdASg@mail.gmail.com>
2020-11-29 23:04 ` [PATCH v2 1/3] dt-bindings: net: fsl-fec add mdc/mdio bitbang option Andrew Lunn
2020-11-30 22:08 ` Florian Fainelli
2020-11-30 22:26 ` Andrew Lunn [this message]
2020-12-04 20:09 ` Adrien Grassein
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=20201130222645.GG2073444@lunn.ch \
--to=andrew@lunn.ch \
--cc=adrien.grassein@gmail.com \
--cc=davem@davemloft.net \
--cc=devicetree@vger.kernel.org \
--cc=f.fainelli@gmail.com \
--cc=fugang.duan@nxp.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=robh+dt@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.