[PATCH net-next v6 1/2] net: fec: Propagate PTP initialization errors

[phucduc.bui@gmail.com]

From: bui duc phuc <phucduc.bui@gmail.com>

Change fec_ptp_init() to return an error code instead of silently
ignoring failures during PTP initialization.

The PPS IRQ is not required for the FEC/PTP functionality, so its
absence should not make the probe fail. However, an unavailable
optional IRQ should be distinguished from an actual error returned
during the IRQ lookup.

If a platform does not support the PPS IRQ, it can omit the IRQ from
its device tree and the optional lookup will return -ENXIO. Propagate
other errors from the IRQ lookup instead of silently ignoring them.
In particular, silently ignoring -EPROBE_DEFER can cause the driver to
continue probing instead of deferring as required.

Also propagate failures from devm_request_irq() and ptp_clock_register().

Update the function declaration in fec.h accordingly.

Found by manual code inspection.

Reviewed-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
---

Link v1:
https://lore.kernel.org/all/20260820111416.97917-1-phucduc.bui@gmail.com/
Link v2:
https://lore.kernel.org/all/20260903092430.354186-1-phucduc.bui@gmail.com/
Link v3:
https://lore.kernel.org/all/20260904105542.70540-1-phucduc.bui@gmail.com/
Link v4:
https://lore.kernel.org/all/20260907034502.12619-1-phucduc.bui@gmail.com/
Link v5: 
https://lore.kernel.org/all/20260909064712.22539-1-phucduc.bui@gmail.com/

Changes in v2:
 - Squash the two patches into one.
 - Add error handling for platform_get_irq_byname_optional().
 - Fix error handling for ptp_clock_register().
Changes in v3:
 - Retarget the patch to the net tree instead of net-next.
 - Add error handling for platform_get_irq_byname_optional()
   in fec_probe() for the fec_enet_interrupt IRQ.
Changes in v4:
 - Use a goto label for cleanup instead of returning directly on errors
   from platform_get_irq_byname_optional() in probe().
 - Update the commit message.
Changes in v5:
 - Split the optional IRQ handling in fec_main.c into a separate patch.
Changes in v6:
 - Add a KDoc comment for fec_ptp_init().
 - Repost this series for net-next without the Fixes: tags.


 drivers/net/ethernet/freescale/fec.h      |  2 +-
 drivers/net/ethernet/freescale/fec_main.c |  7 +++++--
 drivers/net/ethernet/freescale/fec_ptp.c  | 24 +++++++++++++++--------
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/drivers/net/ethernet/freescale/fec.h b/drivers/net/ethernet/freescale/fec.h
index 7176803146f3..8831da37326b 100644
--- a/drivers/net/ethernet/freescale/fec.h
+++ b/drivers/net/ethernet/freescale/fec.h
@@ -692,7 +692,7 @@ struct fec_enet_private {
 	u64 ethtool_stats[];
 };
 
-void fec_ptp_init(struct platform_device *pdev, int irq_idx);
+int fec_ptp_init(struct platform_device *pdev, int irq_idx);
 void fec_ptp_restore_state(struct fec_enet_private *fep);
 void fec_ptp_save_state(struct fec_enet_private *fep);
 void fec_ptp_stop(struct platform_device *pdev);
diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index 794ec427b0ee..c6e29b5c2abb 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -5384,8 +5384,11 @@ fec_probe(struct platform_device *pdev)
 		goto failed_reset;
 
 	irq_cnt = fec_enet_get_irq_cnt(pdev);
-	if (fep->bufdesc_ex)
-		fec_ptp_init(pdev, irq_cnt);
+	if (fep->bufdesc_ex) {
+		ret = fec_ptp_init(pdev, irq_cnt);
+		if (ret)
+			goto failed_reset;
+	}
 
 	ret = fec_enet_init(ndev);
 	if (ret)
diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c
index 56801c2009d5..0574a1a18702 100644
--- a/drivers/net/ethernet/freescale/fec_ptp.c
+++ b/drivers/net/ethernet/freescale/fec_ptp.c
@@ -734,9 +734,11 @@ static irqreturn_t fec_pps_interrupt(int irq, void *dev_id)
  * This function performs the required steps for enabling ptp
  * support. If ptp support has already been loaded it simply calls the
  * cyclecounter init routine and exits.
+ *
+ * Return: 0 on success, or a negative error code on failure.
  */
 
-void fec_ptp_init(struct platform_device *pdev, int irq_idx)
+int fec_ptp_init(struct platform_device *pdev, int irq_idx)
 {
 	struct net_device *ndev = platform_get_drvdata(pdev);
 	struct fec_enet_private *fep = netdev_priv(ndev);
@@ -779,26 +781,32 @@ void fec_ptp_init(struct platform_device *pdev, int irq_idx)
 		      HRTIMER_MODE_REL);
 
 	irq = platform_get_irq_byname_optional(pdev, "pps");
-	if (irq < 0)
+	if (irq < 0 && irq != -ENXIO)
+		return irq;
+	if (irq == -ENXIO) {
 		irq = platform_get_irq_optional(pdev, irq_idx);
-	/* Failure to get an irq is not fatal,
-	 * only the PTP_CLOCK_PPS clock events should stop
-	 */
-	if (irq >= 0) {
+		if (irq < 0 && irq != -ENXIO)
+			return irq;
+	}
+
+	if (irq > 0) {
 		ret = devm_request_irq(&pdev->dev, irq, fec_pps_interrupt,
 				       0, pdev->name, ndev);
 		if (ret < 0)
-			dev_warn(&pdev->dev, "request for pps irq failed(%d)\n",
-				 ret);
+			return ret;
 	}
 
 	fep->ptp_clock = ptp_clock_register(&fep->ptp_caps, &pdev->dev);
 	if (IS_ERR(fep->ptp_clock)) {
+		ret = PTR_ERR(fep->ptp_clock);
 		fep->ptp_clock = NULL;
 		dev_err(&pdev->dev, "ptp_clock_register failed\n");
+		return ret;
 	}
 
 	schedule_delayed_work(&fep->time_keep, HZ);
+
+	return 0;
 }
 
 void fec_ptp_save_state(struct fec_enet_private *fep)
-- 
2.43.0