From: Andrew Lunn <andrew@lunn.ch>
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
Fabio Estevam <festevam@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Russell King <linux@armlinux.org.uk>,
linux-kernel@vger.kernel.org,
Philippe Schenker <philippe.schenker@toradex.com>,
NXP Linux Team <linux-imx@nxp.com>,
Pengutronix Kernel Team <kernel@pengutronix.de>,
Thomas Gleixner <tglx@linutronix.de>,
Shawn Guo <shawnguo@kernel.org>,
Allison Randal <allison@lohutok.net>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: mach-imx6q: add ksz9131rn_phy_fixup
Date: Thu, 5 Mar 2020 17:51:45 +0100 [thread overview]
Message-ID: <20200305165145.GA25183@lunn.ch> (raw)
In-Reply-To: <20200305143805.dk7fndblnqjnwxu6@pengutronix.de>
On Thu, Mar 05, 2020 at 03:38:05PM +0100, Oleksij Rempel wrote:
> Hi Philippe,
>
> On Thu, Mar 05, 2020 at 02:49:28PM +0100, Philippe Schenker wrote:
> > The MAC of the i.MX6 SoC is compliant with RGMII v1.3. The KSZ9131 PHY
> > is like KSZ9031 adhering to RGMII v2.0 specification. This means the
> > MAC should provide a delay to the TXC line. Because the i.MX6 MAC does
> > not provide this delay this has to be done in the PHY.
> >
> > This patch adds by default ~1.6ns delay to the TXC line. This should
> > be good for all boards that have the RGMII signals routed with the
> > same length.
> >
> > The KSZ9131 has relatively high tolerances on skew registers from
> > MMD 2.4 to MMD 2.8. Therefore the new DLL-based delay of 2ns is used
> > and then as little as possibly subtracted from that so we get more
> > accurate delay. This is actually needed because the i.MX6 SoC has
> > an asynchron skew on TXC from -100ps to 900ps, to get all RGMII
> > values within spec.
>
> This configuration has nothing to do in mach-imx/* It belongs to the
> board devicetree. Please see DT binding documentation for needed
> properties:
> Documentation/devicetree/bindings/net/micrel-ksz90x1.txt
It probably does not even need that. Just
phy-mode = <rgmii-txid>
Also, please Cc: netdev for network code.
Andrew
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next prev parent reply other threads:[~2020-03-05 16:52 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-05 13:49 [PATCH] ARM: mach-imx6q: add ksz9131rn_phy_fixup Philippe Schenker
2020-03-05 13:53 ` Russell King - ARM Linux admin
2020-03-06 9:57 ` Philippe Schenker
2020-03-06 10:52 ` Russell King - ARM Linux admin
2020-03-05 14:38 ` Oleksij Rempel
2020-03-05 16:51 ` Andrew Lunn [this message]
2020-03-06 7:42 ` Ahmad Fatoum
2020-03-06 9:46 ` Philippe Schenker
2020-03-06 11:14 ` Ahmad Fatoum
2020-03-06 12:16 ` Philippe Schenker
2020-03-06 13:38 ` Andrew Lunn
2020-03-06 16:30 ` Philippe Schenker
2020-03-06 9:55 ` Philippe Schenker
2020-03-06 10:38 ` Oleksij Rempel
2020-03-06 12:36 ` Philippe Schenker
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