[PATCH 4.9 028/105] net: phy: Do not perform software reset for Generic PHY

From: Greg Kroah-Hartman
Date: Fri Aug 04 2017 - 20:12:54 EST

4.9-stable review patch. If anyone has any objections, please let me know.


From: Florian Fainelli <f.fainelli@xxxxxxxxx>

commit 0878fff1f42c18e448ab5b8b4f6a3eb32365b5b6 upstream.

The Generic PHY driver is a catch-all PHY driver and it should preserve
whatever prior initialization has been done by boot loader or firmware
agents. For specific PHY device configuration it is expected that a
specialized PHY driver would take over that role.

Resetting the generic PHY was a bad idea that has lead to several
complaints and downstream workarounds e.g: in OpenWrt/LEDE so restore
the behavior prior to 87aa9f9c61ad ("net: phy: consolidate PHY
reset in phy_init_hw()").

Reported-by: Felix Fietkau <nbd@xxxxxxxx>
Fixes: 87aa9f9c61ad ("net: phy: consolidate PHY reset in phy_init_hw()")
Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/net/phy/phy_device.c | 2 +-
include/linux/phy.h | 4 ++++
2 files changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1792,7 +1792,7 @@ static struct phy_driver genphy_driver[]
.phy_id = 0xffffffff,
.phy_id_mask = 0xffffffff,
.name = "Generic PHY",
- .soft_reset = genphy_soft_reset,
+ .soft_reset = genphy_no_soft_reset,
.config_init = genphy_config_init,
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -799,6 +799,10 @@ int genphy_read_status(struct phy_device
int genphy_suspend(struct phy_device *phydev);
int genphy_resume(struct phy_device *phydev);
int genphy_soft_reset(struct phy_device *phydev);
+static inline int genphy_no_soft_reset(struct phy_device *phydev)
+ return 0;
void phy_driver_unregister(struct phy_driver *drv);
void phy_drivers_unregister(struct phy_driver *drv, int n);
int phy_driver_register(struct phy_driver *new_driver, struct module *owner);