Re: [PATCH] ARM: mach-imx6q: add ksz9131rn_phy_fixup

From: Andrew Lunn <andrew@lunn.ch>
To: Ahmad Fatoum <a.fatoum@pengutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
	Philippe Schenker <philippe.schenker@toradex.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Russell King <linux@armlinux.org.uk>,
	linux-kernel@vger.kernel.org,
	Oleksij Rempel <o.rempel@pengutronix.de>,
	NXP Linux Team <linux-imx@nxp.com>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Shawn Guo <shawnguo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	Allison Randal <allison@lohutok.net>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: mach-imx6q: add ksz9131rn_phy_fixup
Date: Fri, 6 Mar 2020 14:38:48 +0100	[thread overview]
Message-ID: <20200306133848.GB18310@lunn.ch> (raw)
In-Reply-To: <7191ffe6-642a-477c-ec37-e37dc9be4bf8@pengutronix.de>

> > It probably does not even need that. Just
> > 
> > phy-mode = <rgmii-txid>
> 
> Looks to me like this isn't supported by the Micrel PHY driver or am
> I missing something?

Ah, you are correct. It just has:

        if (of_node) {
                ksz9021_load_values_from_of(phydev, of_node,
                                    MII_KSZPHY_CLK_CONTROL_PAD_SKEW,
                                    "txen-skew-ps", "txc-skew-ps",
                                    "rxdv-skew-ps", "rxc-skew-ps");
                ksz9021_load_values_from_of(phydev, of_node,
                                    MII_KSZPHY_RX_DATA_PAD_SKEW,
                                    "rxd0-skew-ps", "rxd1-skew-ps",
                                    "rxd2-skew-ps", "rxd3-skew-ps");
                ksz9021_load_values_from_of(phydev, of_node,
                                    MII_KSZPHY_TX_DATA_PAD_SKEW,
                                    "txd0-skew-ps", "txd1-skew-ps",
                                    "txd2-skew-ps", "txd3-skew-ps");
        }

and no support for phydev->interface.

At minimum, you should use these DT properties, not a platform fixup.

If you want to, you can add support for rgmii-id, etc. There are five
modes you need to support:

        PHY_INTERFACE_MODE_NA,
        PHY_INTERFACE_MODE_RGMII,
        PHY_INTERFACE_MODE_RGMII_ID,
        PHY_INTERFACE_MODE_RGMII_RXID,
        PHY_INTERFACE_MODE_RGMII_TXID,

NA means "don't touch". Leave the RGMII delays alone, as configured by
hardware default, strapping, bootloader, etc.

	 Andrew

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