[PATCH can-next 5/5] can: tcan4x5x: implement handling of device interrupts

[Torin Cooper-Bennun <torin@maxiluxsystems.com>]

Handle power, transceiver and SPI failures by printing a useful error
message (multiple simultaneous failures are not logged) and disabling
the TCAN4550 by setting it to standby mode.

Additionally, print an error message if any regmap access fails in the
tcan4x5x_handle_dev_interrupts() call.

Signed-off-by: Torin Cooper-Bennun <torin@maxiluxsystems.com>
---
 drivers/net/can/m_can/tcan4x5x-core.c | 50 ++++++++++++++++++++++++++-
 1 file changed, 49 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/m_can/tcan4x5x-core.c b/drivers/net/can/m_can/tcan4x5x-core.c
index a300a14dc5de..2016a4b54a44 100644
--- a/drivers/net/can/m_can/tcan4x5x-core.c
+++ b/drivers/net/can/m_can/tcan4x5x-core.c
@@ -38,6 +38,7 @@
 #define TCAN4X5X_CANDOM_INT_EN BIT(8)
 #define TCAN4X5X_CANBUS_ERR_INT_EN BIT(5)
 #define TCAN4X5X_BUS_FAULT BIT(4)
+#define TCAN4X5X_SPIERR_INT BIT(3)
 #define TCAN4X5X_MCAN_INT BIT(1)
 #define TCAN4X5X_ENABLE_TCAN_INT \
 	(TCAN4X5X_UVSUP_INT_EN | TCAN4X5X_UVIO_INT_EN | TCAN4X5X_TSD_INT_EN | \
@@ -214,7 +215,54 @@ static int tcan4x5x_clear_interrupts(struct m_can_classdev *cdev)
 static irqreturn_t tcan4x5x_handle_dev_interrupts(struct m_can_classdev *cdev,
 						  bool clear_only)
 {
-	tcan4x5x_clear_interrupts(cdev);
+	struct tcan4x5x_priv *priv = cdev_to_priv(cdev);
+	int err = 0;
+	irqreturn_t handled = IRQ_NONE;
+
+	if (!clear_only) {
+		u32 ir = 0;
+		const char *fail_str = "";
+
+		err = regmap_read(priv->regmap, TCAN4X5X_INT_FLAGS, &ir);
+		if (err)
+			goto exit_regmap_failure;
+
+		handled = IRQ_HANDLED;
+
+		if (ir & TCAN4X5X_UVSUP_INT_EN)
+			fail_str = "supply under-voltage (UVSUP)";
+		else if (ir & TCAN4X5X_UVIO_INT_EN)
+			fail_str = "I/O under-voltage (UVIO)";
+		else if (ir & TCAN4X5X_TSD_INT_EN)
+			fail_str = "thermal shutdown (TSD)";
+		else if (ir & TCAN4X5X_ECCERR_INT_EN)
+			fail_str = "uncorrectable ECC error (ECCERR)";
+		else if (ir & TCAN4X5X_CANDOM_INT_EN)
+			fail_str = "CAN stuck dominant (CANDOM)";
+		else if (ir & TCAN4X5X_SPIERR_INT)
+			fail_str = "SPI error (SPIERR)";
+		else
+			handled = IRQ_NONE;
+
+		if (handled == IRQ_HANDLED) {
+			netdev_err(cdev->net, "%s: device is disabled.\n",
+				   fail_str);
+			err = regmap_update_bits(priv->regmap, TCAN4X5X_CONFIG,
+						 TCAN4X5X_MODE_SEL_MASK,
+						 TCAN4X5X_MODE_STANDBY);
+			if (err)
+				goto exit_regmap_failure;
+		}
+	}
+
+	err = tcan4x5x_clear_interrupts(cdev);
+	if (err)
+		goto exit_regmap_failure;
+
+	return handled;
+
+exit_regmap_failure:
+	netdev_err(cdev->net, "regmap access failed in IRQ handler.\n");
 	return IRQ_NONE;
 }
 
-- 
2.30.2