Add support for interrupts for LAN8804 PHY.

Tested-by: Michael Walle <michael@walle.cc> # on kontron-kswitch-d10
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
---
v1->v2:
- add Tested-by and Reviewed-by tags
- add better comments
---
 drivers/net/phy/micrel.c | 62 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c
index 7b8c5c8d013e..6ec2d8fec78a 100644
--- a/drivers/net/phy/micrel.c
+++ b/drivers/net/phy/micrel.c
@@ -2676,6 +2676,66 @@ static int lan8804_config_init(struct phy_device *phydev)
 	return 0;
 }
 
+static irqreturn_t lan8804_handle_interrupt(struct phy_device *phydev)
+{
+	int status;
+
+	status = phy_read(phydev, LAN8814_INTS);
+	if (status < 0) {
+		phy_error(phydev);
+		return IRQ_NONE;
+	}
+
+	if (status > 0)
+		phy_trigger_machine(phydev);
+
+	return IRQ_HANDLED;
+}
+
+#define LAN8804_OUTPUT_CONTROL			25
+#define LAN8804_OUTPUT_CONTROL_INTR_BUFFER	BIT(14)
+#define LAN8804_CONTROL				31
+#define LAN8804_CONTROL_INTR_POLARITY		BIT(14)
+
+static int lan8804_config_intr(struct phy_device *phydev)
+{
+	int err;
+
+	/* This is an internal PHY of lan966x and is not possible to change the
+	 * polarity on the GIC found in lan966x, therefore change the polarity
+	 * of the interrupt in the PHY from being active low instead of active
+	 * high.
+	 */
+	phy_write(phydev, LAN8804_CONTROL, LAN8804_CONTROL_INTR_POLARITY);
+
+	/* By default interrupt buffer is open-drain in which case the interrupt
+	 * can be active only low. Therefore change the interrupt buffer to be
+	 * push-pull to be able to change interrupt polarity
+	 */
+	phy_write(phydev, LAN8804_OUTPUT_CONTROL,
+		  LAN8804_OUTPUT_CONTROL_INTR_BUFFER);
+
+	if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+		err = phy_read(phydev, LAN8814_INTS);
+		if (err < 0)
+			return err;
+
+		err =  phy_write(phydev, LAN8814_INTC, LAN8814_INT_LINK);
+		if (err)
+			return err;
+	} else {
+		err =  phy_write(phydev, LAN8814_INTC, 0);
+		if (err)
+			return err;
+
+		err = phy_read(phydev, LAN8814_INTS);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
 static irqreturn_t lan8814_handle_interrupt(struct phy_device *phydev)
 {
 	int irq_status, tsu_irq_status;
@@ -3137,6 +3197,8 @@ static struct phy_driver ksphy_driver[] = {
 	.get_stats	= kszphy_get_stats,
 	.suspend	= genphy_suspend,
 	.resume		= kszphy_resume,
+	.config_intr	= lan8804_config_intr,
+	.handle_interrupt = lan8804_handle_interrupt,
 }, {
 	.phy_id		= PHY_ID_KSZ9131,
 	.phy_id_mask	= MICREL_PHY_ID_MASK,
-- 
2.33.0

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 13 Sep 2022 16:29:26 +0200 you wrote:
> Add support for interrupts for LAN8804 PHY.
> 
> Tested-by: Michael Walle <michael@walle.cc> # on kontron-kswitch-d10
> Reviewed-by: Andrew Lunn <andrew@lunn.ch>
> Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
> ---
> v1->v2:
> - add Tested-by and Reviewed-by tags
> - add better comments
> 
> [...]

Here is the summary with links:
  - [net-next,v2] net: phy: micrel: Add interrupts support for LAN8804 PHY
    https://git.kernel.org/netdev/net-next/c/b324c6e5e099

You are awesome, thank you!
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