[PATCH net-next] net: phy: realtek: add suspend/resume callbacks for RTL8211B

[Heiner Kallweit <hkallweit1@gmail.com>]

Add RTL8211B suspend / resume callbacks.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
This patch is based on my knowledge of the r8169 driver, and on some
guessing. Therefore I'd appreciate a confirmation from Realtek.

The integrated PHY in some chips supported by the r8169 driver uses
a special sequence for power-down/-up. I have a board with a RTL8168D
network chip (one of the chips using the special sequence) and there
the PHY identifies as RTL8211B. So my guess is that this applies also
to external RTL8211B PHY's.

A hint for RTL8211B requiring a special sequence is that no suspend/
resume callbacks are defined yet in the Realtek PHY driver.
Last but not least the non-standard usage of register MII_MMD_DATA
is in line with the description of patch 0231b1a074c6.
("net: phy: realtek: Use the dummy stubs for MMD register access for rtl8211b")
---
 drivers/net/phy/realtek.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index 9f48ecf9c..082fb40c6 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -145,6 +145,20 @@ static int rtl8211f_config_init(struct phy_device *phydev)
 	return phy_modify_paged(phydev, 0xd08, 0x11, RTL8211F_TX_DELAY, val);
 }
 
+static int rtl8211b_suspend(struct phy_device *phydev)
+{
+	phy_write(phydev, MII_MMD_DATA, BIT(9));
+
+	return genphy_suspend(phydev);
+}
+
+static int rtl8211b_resume(struct phy_device *phydev)
+{
+	phy_write(phydev, MII_MMD_DATA, 0);
+
+	return genphy_resume(phydev);
+}
+
 static struct phy_driver realtek_drvs[] = {
 	{
 		.phy_id         = 0x00008201,
@@ -174,6 +188,8 @@ static struct phy_driver realtek_drvs[] = {
 		.config_intr	= &rtl8211b_config_intr,
 		.read_mmd	= &genphy_read_mmd_unsupported,
 		.write_mmd	= &genphy_write_mmd_unsupported,
+		.suspend	= rtl8211b_suspend,
+		.resume		= rtl8211b_resume,
 	}, {
 		.phy_id		= 0x001cc914,
 		.name		= "RTL8211DN Gigabit Ethernet",
-- 
2.17.0