[PATCH v2 2/2] phy: sunplus: fix ERR_PTR deref in update_disc_vol()

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

nvmem_cell_get() returns ERR_PTR on failure. For any error other
than -EPROBE_DEFER the code fell through and passed the invalid
pointer to nvmem_cell_read(), which dereferences it.

Skip the read and write the default disconnect voltage when the
lookup fails.

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 | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/sunplus/phy-sunplus-usb2.c b/drivers/phy/sunplus/phy-sunplus-usb2.c
index 842087bdfba5..eb834788ea2f 100644
--- a/drivers/phy/sunplus/phy-sunplus-usb2.c
+++ b/drivers/phy/sunplus/phy-sunplus-usb2.c
@@ -84,9 +84,10 @@ static int update_disc_vol(struct sp_usbphy *usbphy)
 	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 skip_nvmem_read;
 	}
 
 	otp_v = nvmem_cell_read(cell, &otp_l);
@@ -101,6 +102,7 @@ static int update_disc_vol(struct sp_usbphy *usbphy)
 		kfree(otp_v);
 	}
 
+skip_nvmem_read:
 	val = readl(usbphy->phy_regs + CONFIG7);
 	val = (val & ~J_DISC) | set;
 	writel(val, usbphy->phy_regs + CONFIG7);

-- 
2.43.0