Messages in this thread | | | Subject | Re: [PATCH v4.1] phylib: Add device reset GPIO support | From | Sergei Shtylyov <> | Date | Thu, 7 Dec 2017 20:20:05 +0300 |
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Hello!
On 12/04/2017 03:35 PM, 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> > [geert: Propagate actual errors from fwnode_get_named_gpiod()] > [geert: Avoid destroying initial setup] > [geert: Consolidate GPIO descriptor acquiring code] > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> [...] > diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c > index 2df7b62c1a36811e..8f8b7747c54bc478 100644 > --- a/drivers/net/phy/mdio_bus.c > +++ b/drivers/net/phy/mdio_bus.c [...] > @@ -48,9 +49,26 @@ > > int mdiobus_register_device(struct mdio_device *mdiodev) > { > + struct gpio_desc *gpiod = NULL; > + > if (mdiodev->bus->mdio_map[mdiodev->addr]) > return -EBUSY; > > + /* Deassert the optional reset signal */
Umm, but why deassert it here for such a short time?
> + if (mdiodev->dev.of_node) > + gpiod = fwnode_get_named_gpiod(&mdiodev->dev.of_node->fwnode, > + "reset-gpios", 0, GPIOD_OUT_LOW, > + "PHY reset"); > + if (PTR_ERR(gpiod) == -ENOENT) > + gpiod = NULL; > + else if (IS_ERR(gpiod)) > + return PTR_ERR(gpiod);
Hm, returning on error with reset deasserted?
> + > + mdiodev->reset = gpiod; > + > + /* Assert the reset signal again */ > + mdio_device_reset(mdiodev, 1); > + > mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev; > > return 0; [...]
MBR, Sergei
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