Merge branch 'net-add-reset-controller-driven-PHY-reset'

David Bauer says:

====================
net: add reset-controller driven PHY reset

This patchset adds support for a PHY reset driven by a reset-controller.
Currently, only GPIO driven resets are supported by the PHY subsystem.
It also renames the reset-gpio from 'reset' to 'reset_gpio' to
better differentiate between resets wired to a GPIO and resets wired to
a reset-controller driven pin.

Some systems have the PHY reset-line wired to a pin controlled by a
reset-controller (eg. some Atheros AR9132 based boards). In case the
bootloader asserts reset before loading the kernel, we currently do not
have a clean way of deasserting reset to probe the PHY.

v3:
 - add missing newline in mdio_bus.c

v2:
 - fixed missed rename of "reset" in at803x.c
 - move initial reset to mdio_device_reset
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/phy.txt

@@ -51,6 +51,10 @@ 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.
 
+- resets: The reset-controller phandle and specifier for the PHY reset signal.
+
+- reset-names: Must be "phy" for the PHY reset signal.
+
 - reset-gpios: The GPIO phandle and specifier for the PHY reset signal.
 
 - reset-assert-us: Delay after the reset was asserted in microseconds.
@@ -67,6 +71,8 @@ ethernet-phy@0 {
 	interrupts = <35 IRQ_TYPE_EDGE_RISING>;
 	reg = <0>;
 
+	resets = <&rst 8>;
+	reset-names = "phy";
 	reset-gpios = <&gpio1 4 GPIO_ACTIVE_LOW>;
 	reset-assert-us = <1000>;
 	reset-deassert-us = <2000>;

drivers/net/phy/at803x.c

@@ -331,7 +331,7 @@ static void at803x_link_change_notify(struct phy_device *phydev)
 	 * in the FIFO. In such cases, the FIFO enters an error mode it
 	 * cannot recover from by software.
 	 */
-	if (phydev->state == PHY_NOLINK && phydev->mdio.reset) {
+	if (phydev->state == PHY_NOLINK && phydev->mdio.reset_gpio) {
 		struct at803x_context context;
 
 		at803x_context_save(phydev, &context);

drivers/net/phy/mdio_bus.c

@@ -24,6 +24,7 @@
 #include <linux/of_gpio.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
+#include <linux/reset.h>
 #include <linux/skbuff.h>
 #include <linux/spinlock.h>
 #include <linux/mm.h>
@@ -55,10 +56,25 @@ static int mdiobus_register_gpiod(struct mdio_device *mdiodev)
 			return PTR_ERR(gpiod);
 	}
 
-	mdiodev->reset = gpiod;
+	mdiodev->reset_gpio = gpiod;
 
-	/* Assert the reset signal again */
-	mdio_device_reset(mdiodev, 1);
+	return 0;
+}
+
+static int mdiobus_register_reset(struct mdio_device *mdiodev)
+{
+	struct reset_control *reset = NULL;
+
+	if (mdiodev->dev.of_node)
+		reset = devm_reset_control_get_exclusive(&mdiodev->dev,
+							 "phy");
+	if (PTR_ERR(reset) == -ENOENT ||
+	    PTR_ERR(reset) == -ENOTSUPP)
+		reset = NULL;
+	else if (IS_ERR(reset))
+		return PTR_ERR(reset);
+
+	mdiodev->reset_ctrl = reset;
 
 	return 0;
 }
@@ -74,6 +90,13 @@ int mdiobus_register_device(struct mdio_device *mdiodev)
 		err = mdiobus_register_gpiod(mdiodev);
 		if (err)
 			return err;
+
+		err = mdiobus_register_reset(mdiodev);
+		if (err)
+			return err;
+
+		/* Assert the reset signal */
+		mdio_device_reset(mdiodev, 1);
 	}
 
 	mdiodev->bus->mdio_map[mdiodev->addr] = mdiodev;
@@ -446,8 +469,8 @@ void mdiobus_unregister(struct mii_bus *bus)
 		if (!mdiodev)
 			continue;
 
-		if (mdiodev->reset)
-			gpiod_put(mdiodev->reset);
+		if (mdiodev->reset_gpio)
+			gpiod_put(mdiodev->reset_gpio);
 
 		mdiodev->device_remove(mdiodev);
 		mdiodev->device_free(mdiodev);

drivers/net/phy/mdio_device.c

@@ -16,6 +16,7 @@
 #include <linux/mii.h>
 #include <linux/module.h>
 #include <linux/phy.h>
+#include <linux/reset.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/unistd.h>
@@ -116,10 +117,18 @@ void mdio_device_reset(struct mdio_device *mdiodev, int value)
 {
 	unsigned int d;
 
-	if (!mdiodev->reset)
+	if (!mdiodev->reset_gpio && !mdiodev->reset_ctrl)
 		return;
 
-	gpiod_set_value(mdiodev->reset, value);
+	if (mdiodev->reset_gpio)
+		gpiod_set_value(mdiodev->reset_gpio, value);
+
+	if (mdiodev->reset_ctrl) {
+		if (value)
+			reset_control_assert(mdiodev->reset_ctrl);
+		else
+			reset_control_deassert(mdiodev->reset_ctrl);
+	}
 
 	d = value ? mdiodev->reset_assert_delay : mdiodev->reset_deassert_delay;
 	if (d)

include/linux/mdio.h

@@ -39,7 +39,8 @@ struct mdio_device {
 	/* Bus address of the MDIO device (0-31) */
 	int addr;
 	int flags;
-	struct gpio_desc *reset;
+	struct gpio_desc *reset_gpio;
+	struct reset_control *reset_ctrl;
 	unsigned int reset_assert_delay;
 	unsigned int reset_deassert_delay;
 };