[PATCH net-next v2 6/7] net: phy: at803x: Avoid hibernating if MAC requires RX clock

Romain Gantois
2024-01-30T09:29:00Z

From: Russell King <linux@armlinux.org.uk>

Stmmac controllers connected to an at803x PHY cannot resume properly after
suspend when WoL is enabled. This happens because the MAC requires an RX
clock generated by the PHY to initialize its hardware properly. But the RX
clock is cut when the PHY suspends and isn't brought up until the MAC
driver resumes the phylink.

Prevent the at803x PHY driver from going into suspend if the attached MAC
driver always requires an RX clock signal.

Reported-by: Clark Wang <xiaoning.wang@nxp.com>
Link: https://lore.kernel.org/all/20230202081559.3553637-1-xiaoning.wang@nxp.com/
Signed-off-by: Russell King <linux@armlinux.org.uk>
[rgantois: commit log]
Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
---
drivers/net/phy/at803x.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/at803x.c b/drivers/net/phy/at803x.c
index 9c07a6cc6e67..5d8d6b89a162 100644
--- a/drivers/net/phy/at803x.c
+++ b/drivers/net/phy/at803x.c
@@ -895,7 +895,8 @@ static int at803x_hibernation_mode_config(struct phy_device *phydev)
/* The default after hardware reset is hibernation mode enabled. After
* software reset, the value is retained.
*/
- if (!(priv->flags & AT803X_DISABLE_HIBERNATION_MODE))
+ if (!(priv->flags & AT803X_DISABLE_HIBERNATION_MODE) &&
+ !(phydev->dev_flags & PHY_F_RXC_ALWAYS_ON))
return 0;

return at803x_debug_reg_mask(phydev, AT803X_DEBUG_REG_HIB_CTRL,