linux-kernel - [PATCH net-next] net: phy: perform a PHY reset on resume

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Date:   Sat, 11 Dec 2021 14:01:46 +0100
From:   Francesco Dolcini <francesco.dolcini@...adex.com>
To:     philippe.schenker@...adex.com, andrew@...n.ch,
        qiangqing.zhang@....com
Cc:     davem@...emloft.net, festevam@...il.com, kuba@...nel.org,
        linux-kernel@...r.kernel.org, linux@...linux.org.uk,
        netdev@...r.kernel.org,
        Francesco Dolcini <francesco.dolcini@...adex.com>
Subject: [PATCH net-next] net: phy: perform a PHY reset on resume

Perform a PHY reset in phy_init_hw() to ensure that the PHY is working
after resume. This is required if the PHY was powered down in suspend
like it is done by the freescale FEC driver in fec_suspend().

Link: https://lore.kernel.org/netdev/20211206101326.1022527-1-philippe.schenker@toradex.com/
Signed-off-by: Francesco Dolcini <francesco.dolcini@...adex.com>

---

Philippe: what about something like that? Only compile tested, but I see no reason for this not solving the issue.

Any delay required on the reset can be specified using reset-assert-us/reset-deassert-us.

---
 drivers/net/phy/phy_device.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 74d8e1dc125f..7eab0c054adf 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1158,7 +1158,8 @@ int phy_init_hw(struct phy_device *phydev)
 {
 	int ret = 0;
 
-	/* Deassert the reset signal */
+	/* phy reset required if the phy was powered down during suspend */
+	phy_device_reset(phydev, 1);
 	phy_device_reset(phydev, 0);
 
 	if (!phydev->drv)
-- 
2.25.1