From: Andrew Lunn <andrew@lunn.ch>
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Florian Fainelli <f.fainelli@gmail.com>,
Heiner Kallweit <hkallweit1@gmail.com>,
kernel@pengutronix.de, netdev@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-imx@nxp.com,
Fabio Estevam <festevam@gmail.com>,
David Jander <david@protonic.nl>,
Russell King <linux@armlinux.org.uk>,
Philippe Schenker <philippe.schenker@toradex.com>
Subject: Re: [PATCH v3 1/7] ARM i.MX6q: remove PHY fixup for KSZ9031
Date: Tue, 11 May 2021 14:49:56 +0200 [thread overview]
Message-ID: <YJp9dCpPWq9wxhhB@lunn.ch> (raw)
In-Reply-To: <20210511043735.30557-2-o.rempel@pengutronix.de>
On Tue, May 11, 2021 at 06:37:29AM +0200, Oleksij Rempel wrote:
> Starting with:
>
> bcf3440c6dd7 ("net: phy: micrel: add phy-mode support for the KSZ9031 PHY")
>
> the micrel phy driver started respecting phy-mode for the KSZ9031 PHY.
> At least with kernel v5.8 configuration provided by this fixup was
> overwritten by the micrel driver.
>
> This fixup was providing following configuration:
>
> RX path: 2.58ns delay
> rx -0.42 (left shift) + rx_clk +0.96ns (right shift) =
> 1,38 + 1,2 internal RX delay = 2.58ns
> TX path: 0.96ns delay
> tx (no delay) + tx_clk 0.96ns (right shift) = 0.96ns
>
> This configuration is outside of the recommended RGMII clock skew delays
> and about in the middle of: rgmii-idrx and rgmii-id
>
> Since most embedded systems do not have enough place to introduce
> significant clock skew, rgmii-id is the way to go.
>
> In case this patch breaks network functionality on your system, build
> kernel with enabled MICREL_PHY. If it is still not working then try
> following device tree options:
> 1. Set (or change) phy-mode in DT to:
> phy-mode = "rgmii-id";
> This actives internal delay for both RX and TX.
> 1. Set (or change) phy-mode in DT to:
> phy-mode = "rgmii-idrx";
> This actives internal delay for RX only.
> 3. Use following DT properties:
> phy-mode = "rgmii";
> txen-skew-psec = <0>;
> rxdv-skew-psec = <0>;
> rxd0-skew-psec = <0>;
> rxd1-skew-psec = <0>;
> rxd2-skew-psec = <0>;
> rxd3-skew-psec = <0>;
> rxc-skew-psec = <1860>;
> txc-skew-psec = <1860>;
> This activates the internal delays for RX and TX, with the value as
> the fixup that is removed in this patch.
>
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Andrew
next prev parent reply other threads:[~2021-05-11 12:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 4:37 [PATCH v3 0/7] remove different PHY fixups Oleksij Rempel
2021-05-11 4:37 ` [PATCH v3 1/7] ARM i.MX6q: remove PHY fixup for KSZ9031 Oleksij Rempel
2021-05-11 12:49 ` Andrew Lunn [this message]
2021-05-11 4:37 ` [PATCH v3 2/7] ARM i.MX6q: remove part of ar8031_phy_fixup() Oleksij Rempel
2021-05-11 12:50 ` Andrew Lunn
2021-05-11 4:37 ` [PATCH v3 3/7] ARM i.MX6q: remove BMCR_PDOWN handler in ar8035_phy_fixup() Oleksij Rempel
2021-05-11 12:50 ` Andrew Lunn
2021-05-11 4:37 ` [PATCH v3 4/7] ARM i.MX6q: remove clk-out fixup for the Atheros AR8031 and AR8035 PHYs Oleksij Rempel
2021-05-11 12:51 ` Andrew Lunn
2021-05-11 4:37 ` [PATCH v3 5/7] ARM i.MX6q: remove Atheros AR8035 SmartEEE fixup Oleksij Rempel
2021-05-11 12:51 ` Andrew Lunn
2021-05-11 4:37 ` [PATCH v3 6/7] ARM: imx6sx: remove Atheros AR8031 PHY fixup Oleksij Rempel
2021-05-11 12:52 ` Andrew Lunn
2021-05-11 4:37 ` [PATCH v3 7/7] ARM: imx7d: " Oleksij Rempel
2021-05-11 12:52 ` Andrew Lunn
2021-05-23 3:34 ` [PATCH v3 0/7] remove different PHY fixups Shawn Guo
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