[PATCH net-next v3 06/12] net: dsa: microchip: ksz9477: basic interrupt support

[Christian Eggers <ceggers@arri.de>]

Interrupts are required for TX time stamping. Probably they could also
be used for PHY connection status.

This patch only adds the basic infrastructure for interrupts, no
interrupts are finally enabled nor handled.

Signed-off-by: Christian Eggers <ceggers@arri.de>
---
 drivers/net/dsa/microchip/ksz9477_i2c.c  |  2 +
 drivers/net/dsa/microchip/ksz9477_main.c | 68 ++++++++++++++++++++++++
 drivers/net/dsa/microchip/ksz9477_spi.c  |  2 +
 drivers/net/dsa/microchip/ksz_common.h   |  1 +
 4 files changed, 73 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz9477_i2c.c b/drivers/net/dsa/microchip/ksz9477_i2c.c
index 4e053a25d077..4ed1f503044a 100644
--- a/drivers/net/dsa/microchip/ksz9477_i2c.c
+++ b/drivers/net/dsa/microchip/ksz9477_i2c.c
@@ -41,6 +41,8 @@ static int ksz9477_i2c_probe(struct i2c_client *i2c,
 	if (i2c->dev.platform_data)
 		dev->pdata = i2c->dev.platform_data;
 
+	dev->irq = i2c->irq;
+
 	ret = ksz9477_switch_register(dev);
 
 	/* Main DSA driver may not be started yet. */
diff --git a/drivers/net/dsa/microchip/ksz9477_main.c b/drivers/net/dsa/microchip/ksz9477_main.c
index c0b4cf66c904..34964f6bf354 100644
--- a/drivers/net/dsa/microchip/ksz9477_main.c
+++ b/drivers/net/dsa/microchip/ksz9477_main.c
@@ -5,9 +5,12 @@
  * Copyright (C) 2017-2019 Microchip Technology Inc.
  */
 
+#include <linux/bits.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
+#include <linux/interrupt.h>
 #include <linux/iopoll.h>
+#include <linux/irq.h>
 #include <linux/platform_data/microchip-ksz.h>
 #include <linux/phy.h>
 #include <linux/if_bridge.h>
@@ -1528,6 +1531,54 @@ static const struct ksz_chip_data ksz9477_switch_chips[] = {
 	},
 };
 
+static irqreturn_t ksz9477_switch_irq_thread(int irq, void *dev_id)
+{
+	struct ksz_device *dev = dev_id;
+	u32 data;
+	int port;
+	int ret;
+
+	/* Read global port interrupt status register */
+	ret = ksz_read32(dev, REG_SW_PORT_INT_STATUS__4, &data);
+	if (ret)
+		return IRQ_NONE;
+
+	for (port = 0; port < dev->port_cnt; port++) {
+		u8 data8;
+
+		if (!(data & BIT(port)))
+			continue;
+
+		/* Read port interrupt status register */
+		ret = ksz_read8(dev, PORT_CTRL_ADDR(port, REG_PORT_INT_STATUS),
+				&data8);
+		if (ret)
+			return IRQ_NONE;
+
+		/* ToDo: Add specific handling of port interrupts */
+	}
+
+	return IRQ_NONE;
+}
+
+static int ksz9477_enable_port_interrupts(struct ksz_device *dev, bool enable)
+{
+	u32 data, mask = GENMASK(dev->port_cnt - 1, 0);
+	int ret;
+
+	ret = ksz_read32(dev, REG_SW_PORT_INT_MASK__4, &data);
+	if (ret)
+		return ret;
+
+	/* bits in REG_SW_PORT_INT_MASK__4 are low active */
+	if (enable)
+		data &= ~mask;
+	else
+		data |= mask;
+
+	return ksz_write32(dev, REG_SW_PORT_INT_MASK__4, data);
+}
+
 static int ksz9477_switch_init(struct ksz_device *dev)
 {
 	int i, ret;
@@ -1583,12 +1634,29 @@ static int ksz9477_switch_init(struct ksz_device *dev)
 
 	/* set the real number of ports */
 	dev->ds->num_ports = dev->port_cnt;
+	if (dev->irq > 0) {
+		ret = devm_request_threaded_irq(dev->dev, dev->irq, NULL,
+						ksz9477_switch_irq_thread,
+						IRQF_ONESHOT | IRQF_SHARED,
+						dev_name(dev->dev),
+						dev);
+		if (ret) {
+			dev_err(dev->dev, "failed to request IRQ.\n");
+			return ret;
+		}
+
+		ret = ksz9477_enable_port_interrupts(dev, true);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }
 
 static void ksz9477_switch_exit(struct ksz_device *dev)
 {
+	if (dev->irq > 0)
+		ksz9477_enable_port_interrupts(dev, false);
 	ksz9477_reset_switch(dev);
 }
 
diff --git a/drivers/net/dsa/microchip/ksz9477_spi.c b/drivers/net/dsa/microchip/ksz9477_spi.c
index 1142768969c2..d2eea9596e53 100644
--- a/drivers/net/dsa/microchip/ksz9477_spi.c
+++ b/drivers/net/dsa/microchip/ksz9477_spi.c
@@ -48,6 +48,8 @@ static int ksz9477_spi_probe(struct spi_device *spi)
 	if (spi->dev.platform_data)
 		dev->pdata = spi->dev.platform_data;
 
+	dev->irq = spi->irq;
+
 	ret = ksz9477_switch_register(dev);
 
 	/* Main DSA driver may not be started yet. */
diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index cf866e48ff66..5df4a7f9df02 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -55,6 +55,7 @@ struct ksz_device {
 
 	struct device *dev;
 	struct regmap *regmap[3];
+	int irq;
 
 	void *priv;
 
-- 
Christian Eggers
Embedded software developer

Arnold & Richter Cine Technik GmbH & Co. Betriebs KG
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