phy: rockchip: inno-usb2: pre-emphasize for rk1808 otg port

This patch open pre-emphasize in non-chirp state for rk1808
otg port to improve Tx eye diagram, and turn off differential
receiver to save power.

Change-Id: I289a3a65a4b1b5ca61ccffb7b38b429e626b19bd
Signed-off-by: William Wu <william.wu@rock-chips.com>

Author: wuliangfeng

drivers/phy/rockchip/phy-rockchip-inno-usb2.c

@@ -1953,6 +1953,23 @@ rockchip_usb2phy_low_power_enable(struct rockchip_usb2phy *rphy,
 	return ret;
 }
 
+static int rk1808_usb2phy_tuning(struct rockchip_usb2phy *rphy)
+{
+	int ret;
+
+	/* Open pre-emphasize in non-chirp state for otg port */
+	ret = regmap_write(rphy->grf, 0x0, 0x00070004);
+	if (ret)
+		return ret;
+
+	/* Turn off differential receiver in suspend mode */
+	ret = regmap_write(rphy->grf, 0x18, 0x00040000);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
 static int rk312x_usb2phy_tuning(struct rockchip_usb2phy *rphy)
 {
 	int ret;
@@ -2248,6 +2265,7 @@ static const struct rockchip_usb2phy_cfg rk1808_phy_cfgs[] = {
 	{
 		.reg = 0x100,
 		.num_ports	= 2,
+		.phy_tuning     = rk1808_usb2phy_tuning,
 		.clkout_ctl	= { 0x108, 4, 4, 1, 0 },
 		.port_cfgs	= {
 			[USB2PHY_PORT_OTG] = {