[PATCH 5.10 069/215] net: phy: realtek: add delay to fix RXC generation issue

[Greg Kroah-Hartman]

From: Joakim Zhang <qiangqing.zhang@xxxxxxx>

[ Upstream commit 6813cc8cfdaf401476e1a007cec8ae338cefa573 ]

PHY will delay about 11.5ms to generate RXC clock when switching from
power down to normal operation. Read/write registers would also cause RXC
become unstable and stop for a while during this process. Realtek engineer
suggests 15ms or more delay can workaround this issue.

Signed-off-by: Joakim Zhang <qiangqing.zhang@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/net/phy/realtek.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index 575580d3ffe0..b4879306bb8a 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -246,6 +246,19 @@ static int rtl8211f_config_init(struct phy_device *phydev)
 	return 0;
 }
 
+static int rtl821x_resume(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = genphy_resume(phydev);
+	if (ret < 0)
+		return ret;
+
+	msleep(20);
+
+	return 0;
+}
+
 static int rtl8211e_config_init(struct phy_device *phydev)
 {
 	int ret = 0, oldpage;
@@ -624,7 +637,7 @@ static struct phy_driver realtek_drvs[] = {
 		.ack_interrupt	= &rtl8211f_ack_interrupt,
 		.config_intr	= &rtl8211f_config_intr,
 		.suspend	= genphy_suspend,
-		.resume		= genphy_resume,
+		.resume		= rtl821x_resume,
 		.read_page	= rtl821x_read_page,
 		.write_page	= rtl821x_write_page,
 	}, {
-- 
2.30.2