[PATCH 3.18 15/50] net: phy: Do not perform software reset for Generic PHY - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Felix Fietkau <nbd@nbd.name>,
	Florian Fainelli <f.fainelli@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Amit Pundir <amit.pundir@linaro.org>
Subject: [PATCH 3.18 15/50] net: phy: Do not perform software reset for Generic PHY
Date: Fri,  4 Aug 2017 16:16:01 -0700	[thread overview]
Message-ID: <20170804231551.751363939@linuxfoundation.org> (raw)
In-Reply-To: <20170804231550.830518786@linuxfoundation.org>

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

------------------

From: Florian Fainelli <f.fainelli@gmail.com>

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@nbd.name>
Fixes: 87aa9f9c61ad ("net: phy: consolidate PHY reset in phy_init_hw()")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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
@@ -1341,7 +1341,7 @@ 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,
 	.features	= PHY_GBIT_FEATURES | SUPPORTED_MII |
 			  SUPPORTED_AUI | SUPPORTED_FIBRE |
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -737,6 +737,10 @@ 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);
