phy: cadence: salvo: Add cdns,usb2-disconnect-threshold-microvolt property

Add cdns,usb2-disconnect-threshold-microvolt property to address fake USB
disconnection issue during enumeration or suspend state for difference
platform.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Link: https://lore.kernel.org/r/20230517161646.3418250-6-Frank.Li@nxp.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: nxpfrankli

drivers/phy/cadence/phy-cadence-salvo.c

@@ -6,6 +6,7 @@
  * Copyright (c) 2019-2020 NXP
  */
 
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -91,9 +92,19 @@
 
 /* USB2 PHY register definition */
 #define UTMI_REG15				0xaf
+#define UTMI_AFE_RX_REG0			0x0d
 #define UTMI_AFE_RX_REG5			0x12
 #define UTMI_AFE_BC_REG4			0x29
 
+/* Align UTMI_AFE_RX_REG0 bit[7:6] define */
+enum usb2_disconn_threshold {
+	USB2_DISCONN_THRESHOLD_575 = 0x0,
+	USB2_DISCONN_THRESHOLD_610 = 0x1,
+	USB2_DISCONN_THRESHOLD_645 = 0x3,
+};
+
+#define RX_USB2_DISCONN_MASK			GENMASK(7, 6)
+
 /* TB_ADDR_TX_RCVDETSC_CTRL */
 #define RXDET_IN_P3_32KHZ			BIT(0)
 /*
@@ -125,6 +136,7 @@ struct cdns_salvo_phy {
 	struct clk *clk;
 	void __iomem *base;
 	struct cdns_salvo_data *data;
+	enum usb2_disconn_threshold usb2_disconn;
 };
 
 static const struct of_device_id cdns_salvo_phy_of_match[];
@@ -260,6 +272,12 @@ static int cdns_salvo_phy_init(struct phy *phy)
 			 value | TXVALID_GATE_THRESHOLD_HS_0US);
 
 	cdns_salvo_write(salvo_phy, USB2_PHY_OFFSET, UTMI_AFE_RX_REG5, 0x5);
+
+	value = cdns_salvo_read(salvo_phy, USB2_PHY_OFFSET, UTMI_AFE_RX_REG0);
+	value &= ~RX_USB2_DISCONN_MASK;
+	value = FIELD_PREP(RX_USB2_DISCONN_MASK, salvo_phy->usb2_disconn);
+	cdns_salvo_write(salvo_phy, USB2_PHY_OFFSET, UTMI_AFE_RX_REG0, value);
+
 	udelay(10);
 
 	clk_disable_unprepare(salvo_phy->clk);
@@ -314,6 +332,7 @@ static int cdns_salvo_phy_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct cdns_salvo_phy *salvo_phy;
 	struct cdns_salvo_data *data;
+	u32 val;
 
 	data = (struct cdns_salvo_data *)of_device_get_match_data(dev);
 	salvo_phy = devm_kzalloc(dev, sizeof(*salvo_phy), GFP_KERNEL);
@@ -325,6 +344,16 @@ static int cdns_salvo_phy_probe(struct platform_device *pdev)
 	if (IS_ERR(salvo_phy->clk))
 		return PTR_ERR(salvo_phy->clk);
 
+	if (of_property_read_u32(dev->of_node, "cdns,usb2-disconnect-threshold-microvolt", &val))
+		val = 575;
+
+	if (val < 610)
+		salvo_phy->usb2_disconn = USB2_DISCONN_THRESHOLD_575;
+	else if (val < 645)
+		salvo_phy->usb2_disconn = USB2_DISCONN_THRESHOLD_610;
+	else
+		salvo_phy->usb2_disconn = USB2_DISCONN_THRESHOLD_645;
+
 	salvo_phy->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(salvo_phy->base))
 		return PTR_ERR(salvo_phy->base);