eth: bcmsysport: fix call balance of priv->clk handling routines

Check the return value of clk_prepare_enable to ensure that priv->clk has
been successfully enabled.

If priv->clk was not enabled during bcm_sysport_probe, bcm_sysport_resume,
or bcm_sysport_open, it must not be disabled in any subsequent execution
paths.

Fixes: 31bc72d ("net: systemport: fetch and use clock resources")
Signed-off-by: Vitalii Mordan <mordan@ispras.ru>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20241227123007.2333397-1-mordan@ispras.ru
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Author: vmordan

drivers/net/ethernet/broadcom/bcmsysport.c

@@ -1933,7 +1933,11 @@ static int bcm_sysport_open(struct net_device *dev)
 	unsigned int i;
 	int ret;
 
-	clk_prepare_enable(priv->clk);
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		netdev_err(dev, "could not enable priv clock\n");
+		return ret;
+	}
 
 	/* Reset UniMAC */
 	umac_reset(priv);
@@ -2591,7 +2595,11 @@ static int bcm_sysport_probe(struct platform_device *pdev)
 		goto err_deregister_notifier;
 	}
 
-	clk_prepare_enable(priv->clk);
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "could not enable priv clock\n");
+		goto err_deregister_netdev;
+	}
 
 	priv->rev = topctrl_readl(priv, REV_CNTL) & REV_MASK;
 	dev_info(&pdev->dev,
@@ -2605,6 +2613,8 @@ static int bcm_sysport_probe(struct platform_device *pdev)
 
 	return 0;
 
+err_deregister_netdev:
+	unregister_netdev(dev);
 err_deregister_notifier:
 	unregister_netdevice_notifier(&priv->netdev_notifier);
 err_deregister_fixed_link:
@@ -2774,7 +2784,12 @@ static int __maybe_unused bcm_sysport_resume(struct device *d)
 	if (!netif_running(dev))
 		return 0;
 
-	clk_prepare_enable(priv->clk);
+	ret = clk_prepare_enable(priv->clk);
+	if (ret) {
+		netdev_err(dev, "could not enable priv clock\n");
+		return ret;
+	}
+
 	if (priv->wolopts)
 		clk_disable_unprepare(priv->wol_clk);