power: reset: linkstation-poweroff: add new device

This commit introduces support for NETGEAR ReadyNAS Duo v2.
This device use bit 4 of LED[2:0] Polarity Control Register to indicate
AC Power loss.

For more details about AC loss detection in NETGEAR ReadyNAS Duo v2,
please look at the file:
RND_5.3.13_WW.src/u-boot/board/mv_feroceon/mv_hal/usibootup/usibootup.c
from Netgear GPL sources.
Signed-off-by: Pawel Dembicki <paweldembicki@gmail.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

drivers/power/reset/linkstation-poweroff.c

@@ -19,6 +19,7 @@
 #define MII_MARVELL_PHY_PAGE		22
 
 #define MII_PHY_LED_CTRL		16
+#define MII_PHY_LED_POL_CTRL		17
 #define MII_88E1318S_PHY_LED_TCR	18
 #define MII_88E1318S_PHY_WOL_CTRL	16
 #define MII_M1011_IEVENT		19
@@ -29,6 +30,8 @@
 #define LED2_FORCE_ON					(0x8 << 8)
 #define LEDMASK						GENMASK(11,8)
 
+#define MII_88E1318S_PHY_LED_POL_LED2		BIT(4)
+
 struct power_off_cfg {
 	char *mdio_node_name;
 	void (*phy_set_reg)(bool restart);
@@ -76,11 +79,47 @@ static void linkstation_mvphy_reg_intn(bool restart)
 		dev_err(&phydev->mdio.dev, "Write register failed, %d\n", rc);
 }
 
+static void readynas_mvphy_set_reg(bool restart)
+{
+	int rc = 0, saved_page;
+	u16 data = 0;
+
+	if (restart)
+		data = MII_88E1318S_PHY_LED_POL_LED2;
+
+	saved_page = phy_select_page(phydev, MII_MARVELL_LED_PAGE);
+	if (saved_page < 0)
+		goto err;
+
+	/* Set the LED[2].0 Polarity bit to the required state */
+	__phy_modify(phydev, MII_PHY_LED_POL_CTRL,
+		     MII_88E1318S_PHY_LED_POL_LED2, data);
+
+	if (!data) {
+		/* If WOL was enabled and a magic packet was received before powering
+		 * off, we won't be able to wake up by sending another magic packet.
+		 * Clear WOL status.
+		 */
+		__phy_write(phydev, MII_MARVELL_PHY_PAGE, MII_MARVELL_WOL_PAGE);
+		__phy_set_bits(phydev, MII_88E1318S_PHY_WOL_CTRL,
+			       MII_88E1318S_PHY_WOL_CTRL_CLEAR_WOL_STATUS);
+	}
+err:
+	rc = phy_restore_page(phydev, saved_page, rc);
+	if (rc < 0)
+		dev_err(&phydev->mdio.dev, "Write register failed, %d\n", rc);
+}
+
 static const struct power_off_cfg linkstation_power_off_cfg = {
 	.mdio_node_name = "mdio",
 	.phy_set_reg = linkstation_mvphy_reg_intn,
 };
 
+static const struct power_off_cfg readynas_power_off_cfg = {
+	.mdio_node_name = "mdio-bus",
+	.phy_set_reg = readynas_mvphy_set_reg,
+};
+
 static int linkstation_reboot_notifier(struct notifier_block *nb,
 				       unsigned long action, void *unused)
 {
@@ -109,6 +148,9 @@ static const struct of_device_id ls_poweroff_of_match[] = {
 	{ .compatible = "buffalo,ls421de",
 	  .data = &linkstation_power_off_cfg,
 	},
+	{ .compatible = "netgear,readynas-duo-v2",
+	  .data = &readynas_power_off_cfg,
+	},
 	{ },
 };