Messages in this thread | | | Subject | Re: [PATCH v3 1/4] phylib: Add device reset GPIO support | From | Sergei Shtylyov <> | Date | Fri, 20 Oct 2017 13:56:04 +0300 |
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Hello!
On 10/20/2017 11:14 AM, Geert Uytterhoeven wrote:
> From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> > > The PHY devices sometimes do have their reset signal (maybe even power > supply?) tied to some GPIO and sometimes it also does happen that a boot > loader does not leave it deasserted. So far this issue has been attacked > from (as I believe) a wrong angle: by teaching the MAC driver to manipulate > the GPIO in question; that solution, when applied to the device trees, led > to adding the PHY reset GPIO properties to the MAC device node, with one > exception: Cadence MACB driver which could handle the "reset-gpios" prop > in a PHY device subnode. I believe that the correct approach is to teach > the 'phylib' to get the MDIO device reset GPIO from the device tree node > corresponding to this device -- which this patch is doing... > > Note that I had to modify the AT803x PHY driver as it would stop working > otherwise -- it made use of the reset GPIO for its own purposes... > > Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> > Acked-by: Rob Herring <robh@kernel.org> > Acked-by: Florian Fainelli <f.fainelli@gmail.com> > [geert: Propagate actual errors from fwnode_get_named_gpiod()] > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> [...] > diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c > index e24f28924af8953d..6926db11ae888174 100644 > --- a/drivers/net/phy/mdio_device.c > +++ b/drivers/net/phy/mdio_device.c [...] > @@ -128,9 +136,16 @@ static int mdio_probe(struct device *dev) > struct mdio_driver *mdiodrv = to_mdio_driver(drv); > int err = 0; > > - if (mdiodrv->probe) > + if (mdiodrv->probe) { > + /* Deassert the reset signal */ > + mdio_device_reset(mdiodev, 0); > + > err = mdiodrv->probe(mdiodev);
If the probe() method performs some register setup...
> + /* Assert the reset signal */ > + mdio_device_reset(mdiodev, 1);
... this reset would kill that setup. Hence we shouldn't drive the reset signal at least when the probe() method succeeds.
> + } > + > return err; > } > [...] > diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c > index 67f25ac29025c539..e694b0ecf780d096 100644 > --- a/drivers/net/phy/phy_device.c > +++ b/drivers/net/phy/phy_device.c [...] > @@ -1811,9 +1826,16 @@ static int phy_probe(struct device *dev) > /* Set the state to READY by default */ > phydev->state = PHY_READY; > > - if (phydev->drv->probe) > + if (phydev->drv->probe) { > + /* Deassert the reset signal */ > + phy_device_reset(phydev, 0); > + > err = phydev->drv->probe(phydev);
If the probe() method performs some register setup (as does the LXT PHY driver!)...
> + /* Assert the reset signal */ > + phy_device_reset(phydev, 1);
... this reset would kill that setup. Hence we shouldn't drive the reset signal at least when the probe() method succeeds.
> + } > + > mutex_unlock(&phydev->lock); > > return err; [...]
MBR, Sergei
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