usb: dwc3-am62: add workaround for Errata i2409

All AM62 devices have Errata i2409 [1] due to which
USB2 PHY may lock up due to short suspend.

Workaround involves setting bit 5 and 4 PLL_REG12
in PHY2 register space after USB controller is brought
out of LPSC reset but before controller initialization.

Handle this workaround.

[1] - https://www.ti.com/lit/er/sprz487d/sprz487d.pdf

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/20240227-for-v6-9-am62-usb-errata-3-0-v4-4-0ada8ddb0767@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/dwc3-am62.c b/drivers/usb/dwc3/dwc3-am62.c
index 09b1f5a1c4fb3eef31c4b9e193ec17a95312d923..fad151e78fd669f7a136d9217a8124ae88f9473c 100644 (file)
--- a/drivers/usb/dwc3/dwc3-am62.c
+++ b/drivers/usb/dwc3/dwc3-am62.c
@@ -101,6 +101,11 @@
 #define PHY_CORE_VOLTAGE_MASK  BIT(31)
 #define PHY_PLL_REFCLK_MASK    GENMASK(3, 0)
 
+/* USB PHY2 register offsets */
+#define        USB_PHY_PLL_REG12               0x130
+#define        USB_PHY_PLL_LDO_REF_EN          BIT(5)
+#define        USB_PHY_PLL_LDO_REF_EN_EN       BIT(4)
+
 #define DWC3_AM62_AUTOSUSPEND_DELAY    100
 
 struct dwc3_am62 {
@@ -184,8 +189,9 @@ static int dwc3_ti_probe(struct platform_device *pdev)
        struct device *dev = &pdev->dev;
        struct device_node *node = pdev->dev.of_node;
        struct dwc3_am62 *am62;
-       int i, ret;
        unsigned long rate;
+       void __iomem *phy;
+       int i, ret;
        u32 reg;
 
        am62 = devm_kzalloc(dev, sizeof(*am62), GFP_KERNEL);
@@ -227,6 +233,17 @@ static int dwc3_ti_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
+       /* Workaround Errata i2409 */
+       phy = devm_platform_ioremap_resource(pdev, 1);
+       if (IS_ERR(phy)) {
+               dev_err(dev, "can't map PHY IOMEM resource. Won't apply i2409 fix.\n");
+               phy = NULL;
+       } else {
+               reg = readl(phy + USB_PHY_PLL_REG12);
+               reg |= USB_PHY_PLL_LDO_REF_EN | USB_PHY_PLL_LDO_REF_EN_EN;
+               writel(reg, phy + USB_PHY_PLL_REG12);
+       }
+
        /* VBUS divider select */
        am62->vbus_divider = device_property_read_bool(dev, "ti,vbus-divider");
        reg = dwc3_ti_readl(am62, USBSS_PHY_CONFIG);