AM654x PG1.0 has a silicon bug that D+ is pulled high after POR, which
could cause enumeration failure with some USB hubs.  Disabling the
USB2_PHY Charger Detect function will put D+ into the normal state.

Using property "ti,disable-charger-det" in the DT usb2-phy node to
enable this workaround for AM654x PG1.0.

This addresses Silicon Errata:
i2075 - "USB2PHY: USB2PHY Charger Detect is Enabled by Default Without VBUS
Presence"

Signed-off-by: Bin Liu <b-...@ti.com>
Signed-off-by: Sekhar Nori <nsek...@ti.com>
Signed-off-by: Roger Quadros <rog...@ti.com>
---
 drivers/phy/ti/phy-omap-usb2.c | 35 +++++++++++++++++++++++++++-------
 1 file changed, 28 insertions(+), 7 deletions(-)

diff --git a/drivers/phy/ti/phy-omap-usb2.c b/drivers/phy/ti/phy-omap-usb2.c
index cb2dd3230fa7..21c3904d4efc 100644
--- a/drivers/phy/ti/phy-omap-usb2.c
+++ b/drivers/phy/ti/phy-omap-usb2.c
@@ -26,6 +26,10 @@
 #define USB2PHY_ANA_CONFIG1            0x4c
 #define USB2PHY_DISCON_BYP_LATCH       BIT(31)
 
+#define USB2PHY_CHRG_DET                       0x14
+#define USB2PHY_CHRG_DET_USE_CHG_DET_REG       BIT(29)
+#define USB2PHY_CHRG_DET_DIS_CHG_DET           BIT(28)
+
 /* SoC Specific USB2_OTG register definitions */
 #define AM654_USB2_OTG_PD              BIT(8)
 #define AM654_USB2_VBUS_DET_EN         BIT(5)
@@ -43,6 +47,7 @@
 #define OMAP_USB2_HAS_START_SRP                        BIT(0)
 #define OMAP_USB2_HAS_SET_VBUS                 BIT(1)
 #define OMAP_USB2_CALIBRATE_FALSE_DISCONNECT   BIT(2)
+#define OMAP_USB2_DISABLE_CHRG_DET             BIT(3)
 
 struct omap_usb {
        struct usb_phy          phy;
@@ -236,6 +241,13 @@ static int omap_usb_init(struct phy *x)
                omap_usb_writel(phy->phy_base, USB2PHY_ANA_CONFIG1, val);
        }
 
+       if (phy->flags & OMAP_USB2_DISABLE_CHRG_DET) {
+               val = omap_usb_readl(phy->phy_base, USB2PHY_CHRG_DET);
+               val |= USB2PHY_CHRG_DET_USE_CHG_DET_REG |
+                      USB2PHY_CHRG_DET_DIS_CHG_DET;
+               omap_usb_writel(phy->phy_base, USB2PHY_CHRG_DET, val);
+       }
+
        return 0;
 }
 
@@ -366,14 +378,12 @@ static int omap_usb2_probe(struct platform_device *pdev)
        phy->mask               = phy_data->mask;
        phy->power_on           = phy_data->power_on;
        phy->power_off          = phy_data->power_off;
+       phy->flags              = phy_data->flags;
 
-       if (phy_data->flags & OMAP_USB2_CALIBRATE_FALSE_DISCONNECT) {
-               res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-               phy->phy_base = devm_ioremap_resource(&pdev->dev, res);
-               if (IS_ERR(phy->phy_base))
-                       return PTR_ERR(phy->phy_base);
-               phy->flags |= OMAP_USB2_CALIBRATE_FALSE_DISCONNECT;
-       }
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       phy->phy_base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(phy->phy_base))
+               return PTR_ERR(phy->phy_base);
 
        phy->syscon_phy_power = syscon_regmap_lookup_by_phandle(node,
                                                        "syscon-phy-power");
@@ -405,6 +415,17 @@ static int omap_usb2_probe(struct platform_device *pdev)
                }
        }
 
+       /*
+        * Errata i2075: USB2PHY: USB2PHY Charger Detect is Enabled by
+        * Default Without VBUS Presence.
+        *
+        * AM654x SR1.0 has a silicon bug due to which D+ is pulled high after
+        * POR, which could cause enumeration failure with some USB hubs.
+        * Disabling the USB2_PHY Charger Detect function will put D+
+        * into the normal state.
+        */
+       if (of_property_read_bool(node, "ti,disable-charger-det"))
+               phy->flags |= OMAP_USB2_DISABLE_CHRG_DET;
 
        phy->wkupclk = devm_clk_get(phy->dev, "wkupclk");
        if (IS_ERR(phy->wkupclk)) {
-- 
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