netdev - [PATCH 4/4] net:phy: fix phy_reset_after_clk

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Message-ID: <CY4PR1701MB18784D5BA799B00DB3B722CEDF160@CY4PR1701MB1878.namprd17.prod.outlook.com>
Date:   Tue, 27 Oct 2020 23:29:42 +0000
From:   "Badel, Laurent" <LaurentBadel@...on.com>
To:     "davem@...emloft.net" <davem@...emloft.net>,
        "m.felsch@...gutronix.de" <m.felsch@...gutronix.de>,
        "fugang.duan@....com" <fugang.duan@....com>,
        "kuba@...nel.org" <kuba@...nel.org>,
        "andrew@...n.ch" <andrew@...n.ch>,
        Heiner Kallweit <hkallweit1@...il.com>,
        "linux@...linux.org.uk" <linux@...linux.org.uk>,
        "p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "richard.leitner@...data.com" <richard.leitner@...data.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "f.fainelli@...il.com" <f.fainelli@...il.com>
CC:     "Quette, Arnaud" <ArnaudQuette@...on.com>
Subject: [PATCH 4/4] net:phy: fix phy_reset_after_clk_enable()

Subject: [PATCH 4/4] net:phy: fix phy_reset_after_clk_enable()

Description: Resetting PHY chip during operation has the effect of
reverting all configuration registers to default. Therefore,
fully re-configure the PHY after a reset.

Also, avoid resetting the PHY if the reset is already asserted,
as this would deassert the reset which might be unexpected for
the entity that previously asserted it.

Signed-off-by: Laurent Badel <laurentbadel@...on.com>
---
 drivers/net/phy/phy_device.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 5dab6be6fc38..85678b1600c0 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1801,7 +1801,7 @@ int phy_loopback(struct phy_device *phydev, bool enable)
 EXPORT_SYMBOL(phy_loopback);

 /**
- * phy_reset_after_clk_enable - perform a PHY reset if needed
+ * phy_reset_after_clk_enable - perform a PHY reset if needed and reconfigure
  * @phydev: target phy_device struct
  *
  * Description: Some PHYs are known to need a reset after their refclk was
@@ -1811,15 +1811,29 @@ EXPORT_SYMBOL(phy_loopback);
  */
 int phy_reset_after_clk_enable(struct phy_device *phydev)
 {
+	int ret;
+
 	if (!phydev || !phydev->drv)
 		return -ENODEV;

-	if (phydev->drv->flags & PHY_RST_AFTER_CLK_EN) {
+	if ((phydev->drv->flags & PHY_RST_AFTER_CLK_EN) &&
+	    !phy_device_reset_status(phydev)) {
+
 		phy_device_reset(phydev, 1);
-		phy_device_reset(phydev, 0);
+		/* phy_init_hw will bring the phy out of reset
+		 * and run its config_init method.
+		 */
+		ret = phy_init_hw(phydev);
+		if (ret < 0)
+			return ret;
+
+		/* re-configure interrupts if needed */
+		if (phydev->interrupts == PHY_INTERRUPT_ENABLED) {
+			phy_free_interrupt(phydev);
+			phy_request_interrupt(phydev);
+		}
 		return 1;
 	}
-
 	return 0;
 }
 EXPORT_SYMBOL(phy_reset_after_clk_enable);
--
2.17.1



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