Re: [PATCH v3] net: phy: add Maxlinear GPY115/21x/24x driver

On 7/6/2021 12:06 pm, Liang Xu wrote:

On 5/6/2021 10:51 pm, Andrew Lunn wrote:

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This email was sent from outside of MaxLinear.

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This does not access vendor specific registers, should not this be part
of the standard genphy_read_abilities() or moved to a helper?

genphy_read_abilities does not cover 2.5G.

genphy_c45_pma_read_abilities checks C45 ids and this check fail if
is_c45 is not set.

You appear to of ignored my comment about this. Please add the helper
to the core as i suggested, and then use
genphy_c45_pma_read_abilities().

           Andrew

I'm new to upstream and do not know the process to change code in core.

Pretty much the same way you change code in a driver. Submit a path!

Please put it into a separate patch, so making a patch series. Please
add some kernel doc style documentation, describing what the function
does. Look at other functions in phy_device.c for examples.

Anybody can change core code. It just gets looked at closer, and need
to be generic.

     Andrew

Thank you. I will create 2 patches for the core modification and driver
separately

in next update.

Hi Andrew,


I need your advice regarding to our recent test in loopback.

My current implementation uses "genphy_loopback" to enable/disable 
loopback mode.

And it has intermittent issue (traffic not loopbacked) during the test 
with net-next.

There are difference in the implementation in net-next and Linux v5.12.

Net-next:

int genphy_loopback(struct phy_device *phydev, bool enable)
{
     if (enable) {
         u16 val, ctl = BMCR_LOOPBACK;
         int ret;

         if (phydev->speed == SPEED_1000)
             ctl |= BMCR_SPEED1000;
         else if (phydev->speed == SPEED_100)
             ctl |= BMCR_SPEED100;

         if (phydev->duplex == DUPLEX_FULL)
             ctl |= BMCR_FULLDPLX;

         phy_modify(phydev, MII_BMCR, ~0, ctl);

         ret = phy_read_poll_timeout(phydev, MII_BMSR, val,
                         val & BMSR_LSTATUS,
                     5000, 500000, true);
         if (ret)
             return ret;
     } else {
         phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, 0);

         phy_config_aneg(phydev);
     }

     return 0;
}

v5.12.11:

int genphy_loopback(struct phy_device *phydev, bool enable)
{
     return phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK,
               enable ? BMCR_LOOPBACK : 0);
}


Not sure whether anyone else reported similar issue.

Should I use phy_modify to set the LOOPBACK bit only in my driver 
implementation as force speed with loopback enable does not work in our 
device?


Thanks & Regards,

Xu Liang