Re: [RFCv1 7/8] phy: amlogic: meson8b-usb2: Power off the PHY by putting it into reset mode.

[Anand Moon]

Hi Martin,

On Fri, 18 Jun 2021 at 04:07, Martin Blumenstingl
<martin.blumenstingl@xxxxxxxxxxxxxx> wrote:
>
> Hi Anand,
>
> On Thu, Jun 17, 2021 at 9:44 PM Anand Moon <linux.amoon@xxxxxxxxx> wrote:
> [...]
> > @@ -245,8 +250,6 @@ static int phy_meson8b_usb2_power_on(struct phy *phy)
> >         regmap_update_bits(priv->regmap, REG_CTRL, REG_CTRL_FSEL_MASK,
> >                            0x5 << REG_CTRL_FSEL_SHIFT);
> >         /* reset the PHY */
> > -       regmap_update_bits(priv->regmap, REG_CTRL, REG_CTRL_POWER_ON_RESET,
> > -                          REG_CTRL_POWER_ON_RESET);
> The vendor driver uses the following sequence for the power on reset:
> - set the power on reset bit
> - wait 500us
> - clear the power on reset bit
> - wait 500us
>
> With your change we now:
> - wait 500us
> - clear the power on reset bit
> - wait 500us
>
> I don't know if this is sufficient to bring the PHY into a well-defined state.
> Maybe it works, maybe it doesn't reset at all in this case - I don't
> know how to verify this though.
>
Initially, I tried to some bit mask code to resolve this but it failed,
So no harm in keeping the original changes.

There is another parameter REG_CTRL_PORT_RESET to be considered.
>
> Best regards,
> Martin

Thanks



-Anand