Re: [PATCH v4 10/14] net: phy: adin: implement PHY subsystem software reset

From: Ardelean, Alexandru
Date: Tue Aug 13 2019 - 01:43:30 EST


On Mon, 2019-08-12 at 16:19 +0200, Andrew Lunn wrote:
> [External]
>
> > +static int adin_reset(struct phy_device *phydev)
> > +{
> > + /* If there is a reset GPIO just exit */
> > + if (!IS_ERR_OR_NULL(phydev->mdio.reset_gpio))
> > + return 0;
>
> I'm not so happy with this.
>
> First off, there are two possible GPIO configurations. The GPIO can be
> applied to all PHYs on the MDIO bus. That GPIO is used when the bus is
> probed. There can also be a per PHY GPIO, which is what you are
> looking at here.
>
> The idea of putting the GPIO handling in the core is that PHYs don't
> need to worry about it. How much of a difference does it make if the
> PHY is both reset via GPIO and then again in software? How slow is the
> software reset? Maybe just unconditionally do the reset, if it is not
> too slow.
>

Ack.
Will do it unconditionally.
The reset is not too slow.


> > +
> > + /* Reset PHY core regs & subsystem regs */
> > + return adin_subsytem_soft_reset(phydev);
> > +}
> > +
> > +static int adin_probe(struct phy_device *phydev)
> > +{
> > + return adin_reset(phydev);
> > +}
>
> Why did you decide to do this as part of probe, and not use the
> .soft_reset member of phy_driver?

Hmmm.
This is a left-over from when I had the GPIO handling in this PHY driver.
It's also a habit picked up from writing IIO drivers, where there is no {soft_}reset hook.
Typically, the reset is done in the probe.

>
> > +
> > static struct phy_driver adin_driver[] = {
> > {
> > PHY_ID_MATCH_MODEL(PHY_ID_ADIN1200),
> > .name = "ADIN1200",
> > .config_init = adin_config_init,
> > + .probe = adin_probe,
> > .config_aneg = adin_config_aneg,
> > .read_status = adin_read_status,
> > .ack_interrupt = adin_phy_ack_intr,
> > @@ -461,6 +503,7 @@ static struct phy_driver adin_driver[] = {
> > PHY_ID_MATCH_MODEL(PHY_ID_ADIN1300),
> > .name = "ADIN1300",
> > .config_init = adin_config_init,
> > + .probe = adin_probe,
> > .config_aneg = adin_config_aneg,
> > .read_status = adin_read_status,
> > .ack_interrupt = adin_phy_ack_intr,
>
> Thanks
> Andrew