net: phy: Add support for driver-specific next update time

Introduce the `phy_get_next_update_time` function to allow PHY drivers
to dynamically determine the time (in jiffies) until the next state
update event. This enables more flexible and adaptive polling intervals
based on the link state or other conditions.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250210082358.200751-2-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: olerem

drivers/net/phy/phy.c

@@ -1501,6 +1501,24 @@ void phy_free_interrupt(struct phy_device *phydev)
 }
 EXPORT_SYMBOL(phy_free_interrupt);
 
+/**
+ * phy_get_next_update_time - Determine the next PHY update time
+ * @phydev: Pointer to the phy_device structure
+ *
+ * This function queries the PHY driver to get the time for the next polling
+ * event. If the driver does not implement the callback, a default value is
+ * used.
+ *
+ * Return: The time for the next polling event in jiffies
+ */
+static unsigned int phy_get_next_update_time(struct phy_device *phydev)
+{
+	if (phydev->drv && phydev->drv->get_next_update_time)
+		return phydev->drv->get_next_update_time(phydev);
+
+	return PHY_STATE_TIME;
+}
+
 enum phy_state_work {
 	PHY_STATE_WORK_NONE,
 	PHY_STATE_WORK_ANEG,
@@ -1580,7 +1598,8 @@ static enum phy_state_work _phy_state_machine(struct phy_device *phydev)
 	 * called from phy_disconnect() synchronously.
 	 */
 	if (phy_polling_mode(phydev) && phy_is_started(phydev))
-		phy_queue_state_machine(phydev, PHY_STATE_TIME);
+		phy_queue_state_machine(phydev,
+					phy_get_next_update_time(phydev));
 
 	return state_work;
 }

include/linux/phy.h

@@ -1270,6 +1270,19 @@ struct phy_driver {
 	 */
 	int (*led_polarity_set)(struct phy_device *dev, int index,
 				unsigned long modes);
+
+	/**
+	 * @get_next_update_time: Get the time until the next update event
+	 * @dev: PHY device
+	 *
+	 * Callback to determine the time (in jiffies) until the next
+	 * update event for the PHY state  machine. Allows PHY drivers to
+	 * dynamically adjust polling intervals based on link state or other
+	 * conditions.
+	 *
+	 * Returns the time in jiffies until the next update event.
+	 */
+	unsigned int (*get_next_update_time)(struct phy_device *dev);
 };
 #define to_phy_driver(d) container_of_const(to_mdio_common_driver(d),		\
 				      struct phy_driver, mdiodrv)