[PATCH v5 phy-next 01/16] phy: lynx-28g: avoid returning NULL in of_xlate() function

[Vladimir Oltean]

Sashiko points out that _of_phy_get() does not support a NULL returned
output from phy_provider->of_xlate(), just a valid pointer or a
pointer-encoded error.

When lynx_28g_probe() -> for_each_available_child_of_node() skips
over lanes which have OF nodes with status = "disabled", the
priv->lane[idx].phy pointer will remain NULL.

This NULL pointer may be propagated to lynx_28g_xlate() if the device
tree contains a phandle to the disabled lane AND fw_devlink did not
block probing for the consumer. In that case, the PHY core will crash
when trying to dereference the NULL phy pointer.

Signed-off-by: Vladimir Oltean <vladimir.oltean at nxp.com>
---
v4->v5:
- deliberately ignoring Sashiko feedback to address the long-standing
  issue that PHY consumers will crash if the provider simply goes away.
  This is not the time and place to address that.
v3->v4: none
v2->v3: patch is new
---
 drivers/phy/freescale/phy-fsl-lynx-28g.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/phy/freescale/phy-fsl-lynx-28g.c b/drivers/phy/freescale/phy-fsl-lynx-28g.c
index 92bfc5f65e0b..cacc128dc96a 100644
--- a/drivers/phy/freescale/phy-fsl-lynx-28g.c
+++ b/drivers/phy/freescale/phy-fsl-lynx-28g.c
@@ -1435,7 +1435,7 @@ static struct phy *lynx_28g_xlate(struct device *dev,
 		    idx < priv->info->first_lane))
 		return ERR_PTR(-EINVAL);
 
-	return priv->lane[idx].phy;
+	return priv->lane[idx].phy ?: ERR_PTR(-ENODEV);
 }
 
 static int lynx_28g_probe_lane(struct lynx_28g_priv *priv, int id,
-- 
2.34.1