Subject: [PATCH AUTOSEL 5.13 095/189] net: phy: realtek: add delay to fix RXC generation issue

From: Sasha Levin <[email-masked]>
Date: Tue, 6 Jul 2021 07:12:35 -0400

From: Joakim Zhang <[email-masked]>

[ 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 <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Sasha Levin <[email-masked]>
---
 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 821e85a97367..7b99a3234c65 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -357,6 +357,19 @@ 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;
@@ -852,7 +865,7 @@ static struct phy_driver realtek_drvs[] = {
 		.config_intr	= &rtl8211f_config_intr,
 		.handle_interrupt = rtl8211f_handle_interrupt,
 		.suspend	= genphy_suspend,
-		.resume		= genphy_resume,
+		.resume		= rtl821x_resume,
 		.read_page	= rtl821x_read_page,
 		.write_page	= rtl821x_write_page,
 	}, {
-- 
2.30.2