phylib: Allow early-out in phy_change

Marvell 88E1121R Dual PHY device can be hardware-configured
to use shared interrupt pin for both PHY ports. For such
PHY configurations using shared PHY interrupt phy_interrupt()
handler will also schedule a work for PHY port which didn't
cause an interrupt.

This patch adds a possibility for PHY drivers to provide
did_interrupt() function which reports if the PHY (or a PHY
port in a multi-PHY device) generated an interrupt. This
function is called in phy_change() as phy_change() shouldn't
proceed if it is invoked for a PHY which didn't cause an
interrupt. So check for interrupt originator in phy_change()
to allow early-out.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 15 insertions, 0 deletions

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 3ff1f425f1bb..e3b8932d7d74 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -655,6 +655,10 @@ static void phy_change(struct work_struct *work)
         struct phy_device *phydev =
                 container_of(work, struct phy_device, phy_queue);
 
+        if (phydev->drv->did_interrupt &&
+            !phydev->drv->did_interrupt(phydev))
+                goto ignore;
+
         err = phy_disable_interrupts(phydev);
 
         if (err)
@@ -681,6 +685,11 @@ static void phy_change(struct work_struct *work)
 
         return;
 
+ignore:
+        atomic_dec(&phydev->irq_disable);
+        enable_irq(phydev->irq);
+        return;
+
 irq_enable_err:
         disable_irq(phydev->irq);
         atomic_inc(&phydev->irq_disable);
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 32cf14a4b034..97e40cb6b588 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -388,6 +388,12 @@ struct phy_driver {
         /* Enables or disables interrupts */
         int (*config_intr)(struct phy_device *phydev);
 
+        /*
+         * Checks if the PHY generated an interrupt.
+         * For multi-PHY devices with shared PHY interrupt pin
+         */
+        int (*did_interrupt)(struct phy_device *phydev);
+
         /* Clears up any memory if needed */
         void (*remove)(struct phy_device *phydev);