Re: [PATCH v3 1/4] phylib: Add device reset GPIO support
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From: Sergei Shtylyov <hidden>
Date: 2017-10-20 10:56:10
Also in:
linux-devicetree, linux-renesas-soc, lkml
Hello! On 10/20/2017 11:14 AM, Geert Uytterhoeven wrote:
From: Sergei Shtylyov <redacted> 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 <redacted> 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>
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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
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@@ -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.
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+ } + return err; }
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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
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@@ -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.
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+ } + mutex_unlock(&phydev->lock); return err;
[...] MBR, Sergei