Commit bafbdd52 authored by Sergei Shtylyov's avatar Sergei Shtylyov Committed by David S. Miller
Browse files

phylib: Add device reset GPIO support 



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: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Acked-by: default avatarRob 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: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: default avatarRichard Leitner <richard.leitner@skidata.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 62b32379

Documentation/devicetree/bindings/net/phy.txt

+2 −0
Original line number Diff line number Diff line
@@ -53,6 +53,8 @@ Optional Properties: 
  to ensure the integrated PHY is used. The absence of this property indicates

  the muxers should be configured so that the external PHY is used.



- reset-gpios: The GPIO phandle and specifier for the PHY reset signal.



Example:



ethernet-phy@0 {

drivers/net/phy/at803x.c

+3 −15
Original line number Diff line number Diff line
@@ -71,7 +71,6 @@ MODULE_LICENSE("GPL"); 


struct at803x_priv {

	bool phy_reset:1;

	struct gpio_desc *gpiod_reset;

};



struct at803x_context {
@@ -254,22 +253,11 @@ static int at803x_probe(struct phy_device *phydev) 
{

	struct device *dev = &phydev->mdio.dev;

	struct at803x_priv *priv;

	struct gpio_desc *gpiod_reset;



	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	if (phydev->drv->phy_id != ATH8030_PHY_ID)

		goto does_not_require_reset_workaround;



	gpiod_reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);

	if (IS_ERR(gpiod_reset))

		return PTR_ERR(gpiod_reset);



	priv->gpiod_reset = gpiod_reset;



does_not_require_reset_workaround:

	phydev->priv = priv;



	return 0;
@@ -343,14 +331,14 @@ static void at803x_link_change_notify(struct phy_device *phydev) 
	 * cannot recover from by software.

	 */

	if (phydev->state == PHY_NOLINK) {

		if (priv->gpiod_reset && !priv->phy_reset) {

		if (phydev->mdio.reset && !priv->phy_reset) {

			struct at803x_context context;



			at803x_context_save(phydev, &context);



			gpiod_set_value(priv->gpiod_reset, 1);

			phy_device_reset(phydev, 1);

			msleep(1);

			gpiod_set_value(priv->gpiod_reset, 0);

			phy_device_reset(phydev, 0);

			msleep(1);



			at803x_context_restore(phydev, &context);

drivers/net/phy/mdio_bus.c

+21 −0
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ 
#include <linux/phy.h>

#include <linux/io.h>

#include <linux/uaccess.h>

#include <linux/gpio/consumer.h>



#include <asm/irq.h>
@@ -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 */

	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);



	mdiodev->reset = gpiod;



	/* Assert the reset signal again */

	mdio_device_reset(mdiodev, 1);



	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;



	return 0;
@@ -420,6 +438,9 @@ void mdiobus_unregister(struct mii_bus *bus) 
		if (!mdiodev)

			continue;



		if (mdiodev->reset)

			gpiod_put(mdiodev->reset);



		mdiodev->device_remove(mdiodev);

		mdiodev->device_free(mdiodev);

	}

drivers/net/phy/mdio_device.c

+23 −2
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/errno.h>

#include <linux/gpio.h>

#include <linux/gpio/consumer.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/kernel.h>
@@ -114,6 +116,13 @@ void mdio_device_remove(struct mdio_device *mdiodev) 
}

EXPORT_SYMBOL(mdio_device_remove);



void mdio_device_reset(struct mdio_device *mdiodev, int value)

{

	if (mdiodev->reset)

		gpiod_set_value(mdiodev->reset, value);

}

EXPORT_SYMBOL(mdio_device_reset);



/**

 * mdio_probe - probe an MDIO device

 * @dev: device to probe
@@ -128,8 +137,16 @@ 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 (err) {

			/* Assert the reset signal */

			mdio_device_reset(mdiodev, 1);

		}

	}



	return err;

}
@@ -140,9 +157,13 @@ static int mdio_remove(struct device *dev) 
	struct device_driver *drv = mdiodev->dev.driver;

	struct mdio_driver *mdiodrv = to_mdio_driver(drv);



	if (mdiodrv->remove)

	if (mdiodrv->remove) {

		mdiodrv->remove(mdiodev);



		/* Assert the reset signal */

		mdio_device_reset(mdiodev, 1);

	}



	return 0;

}

drivers/net/phy/phy_device.c

+30 −2
Original line number Diff line number Diff line
@@ -632,6 +632,9 @@ int phy_device_register(struct phy_device *phydev) 
	if (err)

		return err;



	/* Deassert the reset signal */

	phy_device_reset(phydev, 0);



	/* Run all of the fixups for this PHY */

	err = phy_scan_fixups(phydev);

	if (err) {
@@ -650,6 +653,9 @@ int phy_device_register(struct phy_device *phydev) 
	return 0;



 out:

	/* Assert the reset signal */

	phy_device_reset(phydev, 1);



	mdiobus_unregister_device(&phydev->mdio);

	return err;

}
@@ -666,6 +672,10 @@ EXPORT_SYMBOL(phy_device_register); 
void phy_device_remove(struct phy_device *phydev)

{

	device_del(&phydev->mdio.dev);



	/* Assert the reset signal */

	phy_device_reset(phydev, 1);



	mdiobus_unregister_device(&phydev->mdio);

}

EXPORT_SYMBOL(phy_device_remove);
@@ -849,6 +859,9 @@ int phy_init_hw(struct phy_device *phydev) 
{

	int ret = 0;



	/* Deassert the reset signal */

	phy_device_reset(phydev, 0);



	if (!phydev->drv || !phydev->drv->config_init)

		return 0;
@@ -1126,6 +1139,9 @@ void phy_detach(struct phy_device *phydev) 
	put_device(&phydev->mdio.dev);

	if (ndev_owner != bus->owner)

		module_put(bus->owner);



	/* Assert the reset signal */

	phy_device_reset(phydev, 1);

}

EXPORT_SYMBOL(phy_detach);
@@ -1811,8 +1827,16 @@ 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 (err) {

			/* Assert the reset signal */

			phy_device_reset(phydev, 1);

		}

	}



	mutex_unlock(&phydev->lock);
@@ -1829,8 +1853,12 @@ static int phy_remove(struct device *dev) 
	phydev->state = PHY_DOWN;

	mutex_unlock(&phydev->lock);



	if (phydev->drv && phydev->drv->remove)

	if (phydev->drv && phydev->drv->remove) {

		phydev->drv->remove(phydev);



		/* Assert the reset signal */

		phy_device_reset(phydev, 1);

	}

	phydev->drv = NULL;



	return 0;

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