netdev - [PATCH net-next 3/3] net: phy: clear phydev->suspended after soft reset

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Message-ID: <adbdf4e7-04ed-629e-57e5-2157b2b655da@gmail.com>
Date:   Thu, 23 Apr 2020 21:38:42 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Russell King - ARM Linux <linux@...linux.org.uk>,
        David Miller <davem@...emloft.net>
Cc:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: [PATCH net-next 3/3] net: phy: clear phydev->suspended after soft
 reset

If a soft reset is triggered whilst PHY is in power-down, then
phydev->suspended will remain set. Seems we didn't face any issue yet
caused by this, but better reset the suspended flag after soft reset.

See also the following from 22.2.4.1.1
Resetting a PHY is accomplished by setting bit 0.15 to a logic one.
This action shall set the status and control registers to their default
states.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
---
 drivers/net/phy/phy_device.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index c8f8fd990..7e1ddd574 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1082,8 +1082,12 @@ int phy_init_hw(struct phy_device *phydev)
 	if (!phydev->drv)
 		return 0;
 
-	if (phydev->drv->soft_reset)
+	if (phydev->drv->soft_reset) {
 		ret = phydev->drv->soft_reset(phydev);
+		/* see comment in genphy_soft_reset for an explanation */
+		if (!ret)
+			phydev->suspended = 0;
+	}
 
 	if (ret < 0)
 		return ret;
@@ -2157,6 +2161,12 @@ int genphy_soft_reset(struct phy_device *phydev)
 	if (ret < 0)
 		return ret;
 
+	/* Clause 22 states that setting bit BMCR_RESET sets control registers
+	 * to their default value. Therefore the POWER DOWN bit is supposed to
+	 * be cleared after soft reset.
+	 */
+	phydev->suspended = 0;
+
 	ret = phy_poll_reset(phydev);
 	if (ret)
 		return ret;
-- 
2.26.2