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

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Message-ID: <20201204134826.lnkdtj5nrygsngm2@mchp-dev-shegelun>
Date:   Fri, 4 Dec 2020 14:48:26 +0100
From:   Steen Hegelund <steen.hegelund@...rochip.com>
To:     Andrew Lunn <andrew@...n.ch>
CC:     Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Lars Povlsen <lars.povlsen@...rochip.com>,
        Bjarni Jonasson <bjarni.jonasson@...rochip.com>,
        Microchip UNG Driver List <UNGLinuxDriver@...rochip.com>,
        <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Russell King <rmk+kernel@...linux.org.uk>
Subject: Re: [PATCH v8 3/4] phy: Add Sparx5 ethernet serdes PHY driver

On 03.12.2020 22:52, Andrew Lunn wrote:
>EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
>> +/* 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.

I will update that.

>
>> +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

This is a PHY that communicates on a SerDes link to an ethernet PHY or a
SFP. So I took the lead from earlier work: the Microsemi Ocelot SerDes driver,
and added the Sparx5 SerDes PHY driver here since it is very similar in intent.
It is not an ethernet PHY as such.

BR
Steen

---------------------------------------
Steen Hegelund
steen.hegelund@...rochip.com