[PATCH v2025.09.y 38/58] net: phy: add NULL check for phy driver in page accessors

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

to_phy_driver() can return NULL if the device has no driver bound.
While phy_read_page() and phy_write_page() are only called on bound
devices in practice, the existing error messages already hint at
this possibility ("PHY driver not loaded?").

Add a NULL check for phydrv before dereferencing it, consistent with
the existing error handling.

(cherry picked from commit 9403ba1be4c82ced708a94efc8539e8202a90f57)

Reported-by: GCC 14.2 -fanalyzer
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Link: https://lore.barebox.org/20260216084253.3547270-7-a.fatoum@pengutronix.de
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/net/phy/phy-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index b12f54ed3878..b30cb1dc7349 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -27,7 +27,7 @@ static int phy_read_page(struct phy_device *phydev)
 {
 	struct phy_driver *phydrv = to_phy_driver(phydev->dev.driver);
 
-	if (!phydrv->read_page) {
+	if (!phydrv || !phydrv->read_page) {
 		dev_warn_once(&phydev->dev, "read_page callback not available, PHY driver not loaded?\n");
 		return -EOPNOTSUPP;
 	}
@@ -39,7 +39,7 @@ static int phy_write_page(struct phy_device *phydev, int page)
 {
 	struct phy_driver *phydrv = to_phy_driver(phydev->dev.driver);
 
-	if (!phydrv->write_page) {
+	if (!phydrv || !phydrv->write_page) {
 		dev_warn_once(&phydev->dev, "write_page callback not available, PHY driver not loaded?\n");
 		return -EOPNOTSUPP;
 	}
-- 
2.47.3