Re: [PATCH 1/2] net: phy: marvell-88q2xxx: Enable temperature measurement in probe again

[Stefan Eichenberger]

Hi Dimitri,

On Wed, Feb 19, 2025 at 11:46:47AM +0100, Dimitri Fedrau wrote:
> Hi Stefan,
> 
> thanks for reviewing.
> 
> Am Wed, Feb 19, 2025 at 07:16:58AM +0100 schrieb Stefan Eichenberger:
> > Hi Dimitri,
> > 
> > On Tue, Feb 18, 2025 at 07:33:09PM +0100, Dimitri Fedrau wrote:
> > > Enabling of the temperature sensor was moved from mv88q2xxx_hwmon_probe to
> > > mv88q222x_config_init with the consequence that the sensor is only
> > > usable when the PHY is configured. Enable the sensor in
> > > mv88q2xxx_hwmon_probe as well to fix this.
> > > 
> > > Fixes: a197004cf3c2 ("net: phy: marvell-88q2xxx: Fix temperature measurement with reset-gpios")
> > > Signed-off-by: Dimitri Fedrau <dima.fedrau@xxxxxxxxx>
> > > ---
> > >  drivers/net/phy/marvell-88q2xxx.c | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > > 
> > > diff --git a/drivers/net/phy/marvell-88q2xxx.c b/drivers/net/phy/marvell-88q2xxx.c
> > > index a3996471a1c9a5d4060d5d19ce44aa70e902a83f..30d71bfc365597d77c34c48f05390db9d63c4af4 100644
> > > --- a/drivers/net/phy/marvell-88q2xxx.c
> > > +++ b/drivers/net/phy/marvell-88q2xxx.c
> > > @@ -718,6 +718,13 @@ static int mv88q2xxx_hwmon_probe(struct phy_device *phydev)
> > >  	struct device *dev = &phydev->mdio.dev;
> > >  	struct device *hwmon;
> > >  	char *hwmon_name;
> > > +	int ret;
> > > +
> > > +	/* Enable temperature sense */
> > > +	ret = phy_modify_mmd(phydev, MDIO_MMD_PCS, MDIO_MMD_PCS_MV_TEMP_SENSOR2,
> > > +			     MDIO_MMD_PCS_MV_TEMP_SENSOR2_DIS_MASK, 0);
> > > +	if (ret < 0)
> > > +		return ret;
> > >  
> > >  	priv->enable_temp = true;
> > >  	hwmon_name = devm_hwmon_sanitize_name(dev, dev_name(dev));
> > 
> > Is it necessary to have it enabled in probe and in config? Is that
> > because of the soft reset? Can it happen that the phy is reset but
> > config is not called, then we would end up in the same situation right?
> >
> Even if the phy is not configured yet, it is probed and the PHYs hard reset
> is deasserted, so I can read the temperature. I think the situation you
> mean is when the PHY is brought up and down again. In this case the hard
> reset of the PHY is asserted and I can't read the temperature. That's
> the second patch of the series that fixes this issue.

Okay I see, thanks for the explaination. So the code in
mv88q222x_config_init is required after a hard reset of the phy. I was
just thinking, if we could avoid the duplication but I guess both
enables are required. Could you maybe add a comment why we need to have
it enabled in both places?

Regards,
Stefan