Re: [PATCH v8 3/4] phy: Add Sparx5 ethernet serdes PHY driver

From: Andrew Lunn <andrew@lunn.ch>
To: Steen Hegelund <steen.hegelund@microchip.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>,
	Vinod Koul <vkoul@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	Alexandre Belloni <alexandre.belloni@bootlin.com>,
	Lars Povlsen <lars.povlsen@microchip.com>,
	Bjarni Jonasson <bjarni.jonasson@microchip.com>,
	Microchip UNG Driver List <UNGLinuxDriver@microchip.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	Russell King <rmk+kernel@armlinux.org.uk>
Subject: Re: [PATCH v8 3/4] phy: Add Sparx5 ethernet serdes PHY driver
Date: Thu, 3 Dec 2020 22:52:53 +0100	[thread overview]
Message-ID: <20201203215253.GL2333853@lunn.ch> (raw)
In-Reply-To: <20201203103015.3735373-4-steen.hegelund@microchip.com>

> +/* map from SD25G28 interface width to configuration value */
> +static u8 sd25g28_get_iw_setting(const u8 interface_width)
> +{
> +	switch (interface_width) {
> +	case 10: return 0;
> +	case 16: return 1;
> +	case 32: return 3;
> +	case 40: return 4;
> +	case 64: return 5;
> +	default:
> +		pr_err("%s: Illegal value %d for interface width\n",
> +		       __func__, interface_width);

Please make use of dev_err(phy->dev, so we know which PHY has
configuration problems.

> +static int sparx5_serdes_validate(struct phy *phy, enum phy_mode mode,
> +					int submode,
> +					union phy_configure_opts *opts)
> +{
> +	struct sparx5_serdes_macro *macro = phy_get_drvdata(phy);
> +	struct sparx5_serdes_private *priv = macro->priv;
> +	u32 value, analog_sd;
> +
> +	if (mode != PHY_MODE_ETHERNET)
> +		return -EINVAL;
> +
> +	switch (submode) {
> +	case PHY_INTERFACE_MODE_1000BASEX:
> +	case PHY_INTERFACE_MODE_SGMII:
> +	case PHY_INTERFACE_MODE_QSGMII:
> +	case PHY_INTERFACE_MODE_10GBASER:
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +	if (macro->serdestype == SPX5_SDT_6G) {
> +		value = sdx5_rd(priv, SD6G_LANE_LANE_DF(macro->stpidx));
> +		analog_sd = SD6G_LANE_LANE_DF_PMA2PCS_RXEI_FILTERED_GET(value);
> +	} else if (macro->serdestype == SPX5_SDT_10G) {
> +		value = sdx5_rd(priv, SD10G_LANE_LANE_DF(macro->stpidx));
> +		analog_sd = SD10G_LANE_LANE_DF_PMA2PCS_RXEI_FILTERED_GET(value);
> +	} else {
> +		value = sdx5_rd(priv, SD25G_LANE_LANE_DE(macro->stpidx));
> +		analog_sd = SD25G_LANE_LANE_DE_LN_PMA_RXEI_GET(value);
> +	}
> +	/* Link up is when analog_sd == 0 */
> +	return analog_sd;
> +}

What i have not yet seen is how this code plugs together with
phylink_pcs_ops?

Can this hardware also be used for SATA, USB? As far as i understand,
the Marvell Comphy is multi-purpose, it is used for networking, USB,
and SATA, etc. Making it a generic PHY then makes sense, because
different subsystems need to use it.

But it looks like this is for networking only? So i'm wondering if it
belongs in driver/net/pcs and it should be accessed using
phylink_pcs_ops?

	Andrew