[PATCH] phy: broadcom: brcm-usb: unwind clocks on probe failure

[Myeonghun Pak <mhun512@gmail.com>]

brcm_usb_phy_dvr_init() enables the optional USB2 and USB3 clocks before
creating all PHYs and acquiring the remaining probe resources.  Several
later failures return without disabling clocks that were already enabled,
and deferred probe retries can keep increasing their enable counts.

Track each successful clock enable and unwind only those clocks, in reverse
order, when initialization fails.  Keep the existing successful probe path
unchanged.  This is limited to the BCM4908 and Broadcom STB USB PHY driver.

This issue was identified during our ongoing static-analysis research while
reviewing kernel code.

Fixes: 49859e55e364 ("phy: usb: phy-brcm-usb: Add Broadcom STB USB phy driver")
Assisted-by: OpenAI:GPT-5.6
Co-developed-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Ijae Kim <ae878000@gmail.com>
Signed-off-by: Myeonghun Pak <mhun512@gmail.com>
---
 drivers/phy/broadcom/phy-brcm-usb.c | 48 +++++++++++++++++++++--------
 1 file changed, 35 insertions(+), 13 deletions(-)

diff --git a/drivers/phy/broadcom/phy-brcm-usb.c b/drivers/phy/broadcom/phy-brcm-usb.c
index 59d756a10..273f7b586 100644
--- a/drivers/phy/broadcom/phy-brcm-usb.c
+++ b/drivers/phy/broadcom/phy-brcm-usb.c
@@ -404,6 +404,8 @@ static int brcm_usb_phy_dvr_init(struct platform_device *pdev,
 {
 	struct device *dev = &pdev->dev;
 	struct phy *gphy = NULL;
+	bool usb_20_clk_enabled = false;
+	bool usb_30_clk_enabled = false;
 	int err;
 
 	priv->usb_20_clk = of_clk_get_by_name(dn, "sw_usb");
@@ -413,15 +415,19 @@ static int brcm_usb_phy_dvr_init(struct platform_device *pdev,
 		dev_info(dev, "Clock not found in Device Tree\n");
 		priv->usb_20_clk = NULL;
 	}
-	err = clk_prepare_enable(priv->usb_20_clk);
-	if (err)
-		return err;
+	if (priv->usb_20_clk) {
+		err = clk_prepare_enable(priv->usb_20_clk);
+		if (err)
+			return err;
+		usb_20_clk_enabled = true;
+	}
 
 	if (priv->has_eohci) {
 		gphy = devm_phy_create(dev, NULL, &brcm_usb_phy_ops);
 		if (IS_ERR(gphy)) {
 			dev_err(dev, "failed to create EHCI/OHCI PHY\n");
-			return PTR_ERR(gphy);
+			err = PTR_ERR(gphy);
+			goto err_disable_clks;
 		}
 		priv->phys[BRCM_USB_PHY_2_0].phy = gphy;
 		priv->phys[BRCM_USB_PHY_2_0].id = BRCM_USB_PHY_2_0;
@@ -432,7 +438,8 @@ static int brcm_usb_phy_dvr_init(struct platform_device *pdev,
 		gphy = devm_phy_create(dev, NULL, &brcm_usb_phy_ops);
 		if (IS_ERR(gphy)) {
 			dev_err(dev, "failed to create XHCI PHY\n");
-			return PTR_ERR(gphy);
+			err = PTR_ERR(gphy);
+			goto err_disable_clks;
 		}
 		priv->phys[BRCM_USB_PHY_3_0].phy = gphy;
 		priv->phys[BRCM_USB_PHY_3_0].id = BRCM_USB_PHY_3_0;
@@ -440,21 +447,28 @@ static int brcm_usb_phy_dvr_init(struct platform_device *pdev,
 
 		priv->usb_30_clk = of_clk_get_by_name(dn, "sw_usb3");
 		if (IS_ERR(priv->usb_30_clk)) {
-			if (PTR_ERR(priv->usb_30_clk) == -EPROBE_DEFER)
-				return -EPROBE_DEFER;
+			if (PTR_ERR(priv->usb_30_clk) == -EPROBE_DEFER) {
+				err = -EPROBE_DEFER;
+				goto err_disable_clks;
+			}
 			dev_info(dev,
 				 "USB3.0 clock not found in Device Tree\n");
 			priv->usb_30_clk = NULL;
 		}
-		err = clk_prepare_enable(priv->usb_30_clk);
-		if (err)
-			return err;
+		if (priv->usb_30_clk) {
+			err = clk_prepare_enable(priv->usb_30_clk);
+			if (err)
+				goto err_disable_clks;
+			usb_30_clk_enabled = true;
+		}
 	}
 
 	priv->suspend_clk = clk_get(dev, "usb0_freerun");
 	if (IS_ERR(priv->suspend_clk)) {
-		if (PTR_ERR(priv->suspend_clk) == -EPROBE_DEFER)
-			return -EPROBE_DEFER;
+		if (PTR_ERR(priv->suspend_clk) == -EPROBE_DEFER) {
+			err = -EPROBE_DEFER;
+			goto err_disable_clks;
+		}
 		dev_err(dev, "Suspend Clock not found in Device Tree\n");
 		priv->suspend_clk = NULL;
 	}
@@ -467,7 +481,7 @@ static int brcm_usb_phy_dvr_init(struct platform_device *pdev,
 				       brcm_usb_phy_wake_isr, 0,
 				       dev_name(dev), dev);
 		if (err < 0)
-			return err;
+			goto err_disable_clks;
 		device_set_wakeup_capable(dev, 1);
 	} else {
 		dev_info(dev,
@@ -475,6 +489,14 @@ static int brcm_usb_phy_dvr_init(struct platform_device *pdev,
 	}
 
 	return 0;
+
+err_disable_clks:
+	if (usb_30_clk_enabled)
+		clk_disable_unprepare(priv->usb_30_clk);
+	if (usb_20_clk_enabled)
+		clk_disable_unprepare(priv->usb_20_clk);
+
+	return err;
 }
 
 static int brcm_usb_phy_probe(struct platform_device *pdev)
-- 
2.47.1