[PATCH 13/15] net: phy: mdio: add support for PHY supply regulator

From: Bartosz Golaszewski
Date: Mon Jun 22 2020 - 05:42:10 EST


From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>

Currently many MAC drivers control the regulator supplying the PHY but
this is conceptually wrong. The regulator should be defined as a property
of the PHY node on the MDIO bus and controlled by the MDIO sub-system.

Add support for an optional PHY regulator which will be enabled before
optional deasserting of the reset signal.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
drivers/net/phy/mdio_bus.c | 21 ++++++++++++++++++++
drivers/net/phy/mdio_device.c | 36 +++++++++++++++++++++++++++++++++++
include/linux/mdio.h | 3 +++
3 files changed, 60 insertions(+)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 53e2fb0be7b9..19f0b9664fe3 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -27,6 +27,7 @@
#include <linux/of_gpio.h>
#include <linux/of_mdio.h>
#include <linux/phy.h>
+#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
@@ -67,6 +68,22 @@ static int mdiobus_register_reset(struct mdio_device *mdiodev)
return 0;
}

+static int mdiobus_register_regulator(struct mdio_device *mdiodev)
+{
+ struct regulator *phy_supply;
+
+ phy_supply = regulator_get_optional(&mdiodev->dev, "phy");
+ if (IS_ERR(phy_supply)) {
+ if (PTR_ERR(phy_supply) == -EPROBE_DEFER)
+ return -EPROBE_DEFER;
+ phy_supply = NULL;
+ }
+
+ mdiodev->phy_supply = phy_supply;
+
+ return 0;
+}
+
int mdiobus_register_device(struct mdio_device *mdiodev)
{
int err;
@@ -83,6 +100,10 @@ int mdiobus_register_device(struct mdio_device *mdiodev)
if (err)
return err;

+ err = mdiobus_register_regulator(mdiodev);
+ if (err)
+ return err;
+
/* Assert the reset signal */
mdio_device_reset(mdiodev, 1);
}
diff --git a/drivers/net/phy/mdio_device.c b/drivers/net/phy/mdio_device.c
index be615504b829..0f698d7a770b 100644
--- a/drivers/net/phy/mdio_device.c
+++ b/drivers/net/phy/mdio_device.c
@@ -17,6 +17,7 @@
#include <linux/mii.h>
#include <linux/module.h>
#include <linux/phy.h>
+#include <linux/regulator/consumer.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <linux/string.h>
@@ -136,6 +137,32 @@ void mdio_device_reset(struct mdio_device *mdiodev, int value)
}
EXPORT_SYMBOL(mdio_device_reset);

+int mdio_device_power_on(struct mdio_device *mdiodev)
+{
+ int ret = 0;
+
+ if (mdiodev->phy_supply)
+ /* TODO We may need a delay here just like reset_assert_delay
+ * but since no user currently needs it, I'm not adding it just
+ * yet.
+ */
+ ret = regulator_enable(mdiodev->phy_supply);
+
+ return ret;
+}
+EXPORT_SYMBOL(mdio_device_power_on);
+
+int mdio_device_power_off(struct mdio_device *mdiodev)
+{
+ int ret = 0;
+
+ if (mdiodev->phy_supply)
+ ret = regulator_disable(mdiodev->phy_supply);
+
+ return ret;
+}
+EXPORT_SYMBOL(mdio_device_power_off);
+
/**
* mdio_probe - probe an MDIO device
* @dev: device to probe
@@ -150,6 +177,11 @@ static int mdio_probe(struct device *dev)
struct mdio_driver *mdiodrv = to_mdio_driver(drv);
int err = 0;

+ /* Enable the power supply */
+ err = mdio_device_power_on(mdiodev);
+ if (err)
+ return err;
+
/* Deassert the reset signal */
mdio_device_reset(mdiodev, 0);

@@ -158,6 +190,8 @@ static int mdio_probe(struct device *dev)
if (err) {
/* Assert the reset signal */
mdio_device_reset(mdiodev, 1);
+ /* Disable the power supply */
+ mdio_device_power_off(mdiodev);
}
}

@@ -175,6 +209,8 @@ static int mdio_remove(struct device *dev)

/* Assert the reset signal */
mdio_device_reset(mdiodev, 1);
+ /* Disable the power supply */
+ mdio_device_power_off(mdiodev);

return 0;
}
diff --git a/include/linux/mdio.h b/include/linux/mdio.h
index 9ac5e7ff6156..0ae07365a6ca 100644
--- a/include/linux/mdio.h
+++ b/include/linux/mdio.h
@@ -46,6 +46,7 @@ struct mdio_device {
int flags;
struct gpio_desc *reset_gpio;
struct reset_control *reset_ctrl;
+ struct regulator *phy_supply;
unsigned int reset_assert_delay;
unsigned int reset_deassert_delay;
};
@@ -92,6 +93,8 @@ struct mdio_device *mdio_device_create(struct mii_bus *bus, int addr);
int mdio_device_register(struct mdio_device *mdiodev);
void mdio_device_remove(struct mdio_device *mdiodev);
void mdio_device_reset(struct mdio_device *mdiodev, int value);
+int mdio_device_power_on(struct mdio_device *mdiodev);
+int mdio_device_power_off(struct mdio_device *mdiodev);
int mdio_driver_register(struct mdio_driver *drv);
void mdio_driver_unregister(struct mdio_driver *drv);
int mdio_device_bus_match(struct device *dev, struct device_driver *drv);
--
2.26.1