From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

Introduce FLEXCAN_QUIRK_IRQ_BERR quirk to handle hardware integration
where the FlexCAN module has a dedicated interrupt line for signaling
bus errors and device state changes.

This adds the flexcan_irq_esr() handler which composes
flexcan_do_state() and flexcan_do_berr() to handle platforms where
these events share a single IRQ line.

This is required for NXP S32N79 SoC support.

Co-developed-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
---
 drivers/net/can/flexcan/flexcan-core.c | 44 +++++++++++++++++++++++---
 drivers/net/can/flexcan/flexcan.h      |  2 ++
 2 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/drivers/net/can/flexcan/flexcan-core.c b/drivers/net/can/flexcan/flexcan-core.c
index da712972d5de..51f60bbf25fa 100644
--- a/drivers/net/can/flexcan/flexcan-core.c
+++ b/drivers/net/can/flexcan/flexcan-core.c
@@ -1283,6 +1283,22 @@ static irqreturn_t flexcan_irq_boff(int irq, void *dev_id)
 	return handled;
 }
 
+/* Combined bus error and state change IRQ handler */
+static irqreturn_t flexcan_irq_esr(int irq, void *dev_id)
+{
+	struct net_device *dev = dev_id;
+	struct flexcan_priv *priv = netdev_priv(dev);
+	irqreturn_t handled;
+
+	handled = flexcan_do_state(dev);
+	handled |= flexcan_do_berr(dev);
+
+	if (handled)
+		can_rx_offload_irq_finish(&priv->offload);
+
+	return handled;
+}
+
 static void flexcan_set_bittiming_ctrl(const struct net_device *dev)
 {
 	const struct flexcan_priv *priv = netdev_priv(dev);
@@ -1850,7 +1866,8 @@ static int flexcan_open(struct net_device *dev)
 
 	can_rx_offload_enable(&priv->offload);
 
-	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
+	if (priv->devtype_data.quirks &
+			(FLEXCAN_QUIRK_NR_IRQ_3 | FLEXCAN_QUIRK_IRQ_BERR))
 		err = request_irq(dev->irq, flexcan_irq_mb,
 				  IRQF_SHARED, dev->name, dev);
 	else
@@ -1871,6 +1888,13 @@ static int flexcan_open(struct net_device *dev)
 			goto out_free_irq_boff;
 	}
 
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_IRQ_BERR) {
+		err = request_irq(priv->irq_err,
+				  flexcan_irq_esr, IRQF_SHARED, dev->name, dev);
+		if (err)
+			goto out_free_irq_boff;
+	}
+
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ) {
 		err = request_irq(priv->irq_secondary_mb,
 				  flexcan_irq_mb, IRQF_SHARED, dev->name, dev);
@@ -1885,7 +1909,8 @@ static int flexcan_open(struct net_device *dev)
 	return 0;
 
  out_free_irq_err:
-	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
+	if (priv->devtype_data.quirks &
+			(FLEXCAN_QUIRK_IRQ_BERR | FLEXCAN_QUIRK_NR_IRQ_3))
 		free_irq(priv->irq_err, dev);
  out_free_irq_boff:
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
@@ -1917,10 +1942,12 @@ static int flexcan_close(struct net_device *dev)
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_SECONDARY_MB_IRQ)
 		free_irq(priv->irq_secondary_mb, dev);
 
-	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
+	if (priv->devtype_data.quirks &
+			(FLEXCAN_QUIRK_IRQ_BERR | FLEXCAN_QUIRK_NR_IRQ_3))
 		free_irq(priv->irq_err, dev);
+
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3)
 		free_irq(priv->irq_boff, dev);
-	}
 
 	free_irq(dev->irq, dev);
 	can_rx_offload_disable(&priv->offload);
@@ -2307,12 +2334,21 @@ static int flexcan_probe(struct platform_device *pdev)
 	if (transceiver)
 		priv->can.bitrate_max = transceiver->attrs.max_link_rate;
 
+	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_IRQ_BERR) {
+		priv->irq_err = platform_get_irq_byname(pdev, "berr");
+		if (priv->irq_err < 0) {
+			err = priv->irq_err;
+			goto failed_platform_get_irq;
+		}
+	}
+
 	if (priv->devtype_data.quirks & FLEXCAN_QUIRK_NR_IRQ_3) {
 		priv->irq_boff = platform_get_irq(pdev, 1);
 		if (priv->irq_boff < 0) {
 			err = priv->irq_boff;
 			goto failed_platform_get_irq;
 		}
+
 		priv->irq_err = platform_get_irq(pdev, 2);
 		if (priv->irq_err < 0) {
 			err = priv->irq_err;
diff --git a/drivers/net/can/flexcan/flexcan.h b/drivers/net/can/flexcan/flexcan.h
index 16692a2502eb..bbb1a8dd4777 100644
--- a/drivers/net/can/flexcan/flexcan.h
+++ b/drivers/net/can/flexcan/flexcan.h
@@ -74,6 +74,8 @@
  * both need to have an interrupt handler registered.
  */
 #define FLEXCAN_QUIRK_SECONDARY_MB_IRQ	BIT(18)
+/* Setup dedicated bus error and state change IRQ */
+#define FLEXCAN_QUIRK_IRQ_BERR	BIT(19)
 
 struct flexcan_devtype_data {
 	u32 quirks;		/* quirks needed for different IP cores */
-- 
2.43.0