[PATCH] phy: sunplus: fix crash when the disc_vol nvmem cell is missing

[Felix Gu <ustc.gu@gmail.com>]

nvmem_cell_get() can fail with errors other than -EPROBE_DEFER, but
update_disc_vol() only handled -EPROBE_DEFER and then called
nvmem_cell_read() with the error pointer, crashing the kernel.

Fall back to the default disconnect voltage on a failed cell lookup,
and free the buffer returned by nvmem_cell_read().

Fixes: 99d9ccd97385 ("phy: usb: Add USB2.0 phy driver for Sunplus SP7021")
Signed-off-by: Felix Gu <ustc.gu@gmail.com>
---
 drivers/phy/sunplus/phy-sunplus-usb2.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/phy/sunplus/phy-sunplus-usb2.c b/drivers/phy/sunplus/phy-sunplus-usb2.c
index 637a5fbae6d9..94146118e9c2 100644
--- a/drivers/phy/sunplus/phy-sunplus-usb2.c
+++ b/drivers/phy/sunplus/phy-sunplus-usb2.c
@@ -81,12 +81,13 @@ static int update_disc_vol(struct sp_usbphy *usbphy)
 	char *disc_name = "disc_vol";
 	ssize_t otp_l = 0;
 	char *otp_v;
-	u32 val, set;
+	u32 val, set = OTP_DISC_LEVEL_DEFAULT;
 
 	cell = nvmem_cell_get(usbphy->dev, disc_name);
-	if (IS_ERR_OR_NULL(cell)) {
+	if (IS_ERR(cell)) {
 		if (PTR_ERR(cell) == -EPROBE_DEFER)
 			return -EPROBE_DEFER;
+		goto out;
 	}
 
 	otp_v = nvmem_cell_read(cell, &otp_l);
@@ -96,11 +97,12 @@ static int update_disc_vol(struct sp_usbphy *usbphy)
 		set = *(otp_v + 1);
 		set = (set << (sizeof(char) * 8)) | *otp_v;
 		set = (set >> usbphy->disc_vol_addr_off) & J_DISC;
+		if (set == 0)
+			set = OTP_DISC_LEVEL_DEFAULT;
+		kfree(otp_v);
 	}
 
-	if (IS_ERR(otp_v) || set == 0)
-		set = OTP_DISC_LEVEL_DEFAULT;
-
+out:
 	val = readl(usbphy->phy_regs + CONFIG7);
 	val = (val & ~J_DISC) | set;
 	writel(val, usbphy->phy_regs + CONFIG7);

---
base-commit: 9a4cdc958dd79fc6c3b20b51a10debec6ca09fec
change-id: 20260804-sunplus-53a7bb1bcd72

Best regards,
--  
Felix Gu <ustc.gu@gmail.com>