usb: cdns3: Add quirk flag to enable suspend residency

Some platforms (e.g. ti,j721e-usb, ti,am64-usb) require
this bit to be set to workaround a lockup issue with PHY
short suspend intervals [1]. Add a platform quirk flag
to indicate if Suspend Residency should be enabled.

[1] - https://www.ti.com/lit/er/sprz457h/sprz457h.pdf
i2409 - USB: USB2 PHY locks up due to short suspend

Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
Acked-by: Peter Chen <peter.chen@kernel.org>
Link: https://lore.kernel.org/r/20240516044537.16801-2-r-gunasekaran@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/cdns3/core.h

@@ -44,6 +44,7 @@ struct cdns3_platform_data {
 			bool suspend, bool wakeup);
 	unsigned long quirks;
 #define CDNS3_DEFAULT_PM_RUNTIME_ALLOW	BIT(0)
+#define CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE	BIT(1)
 };
 
 /**

drivers/usb/cdns3/drd.c

@@ -389,7 +389,7 @@ static irqreturn_t cdns_drd_irq(int irq, void *data)
 int cdns_drd_init(struct cdns *cdns)
 {
 	void __iomem *regs;
-	u32 state;
+	u32 state, reg;
 	int ret;
 
 	regs = devm_ioremap_resource(cdns->dev, &cdns->otg_res);
@@ -433,6 +433,14 @@ int cdns_drd_init(struct cdns *cdns)
 			cdns->otg_irq_regs = (struct cdns_otg_irq_regs __iomem *)
 					      &cdns->otg_v1_regs->ien;
 			writel(1, &cdns->otg_v1_regs->simulate);
+
+			if (cdns->pdata &&
+			    (cdns->pdata->quirks & CDNS3_DRD_SUSPEND_RESIDENCY_ENABLE)) {
+				reg = readl(&cdns->otg_v1_regs->susp_ctrl);
+				reg |= SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE;
+				writel(reg, &cdns->otg_v1_regs->susp_ctrl);
+			}
+
 			cdns->version  = CDNS3_CONTROLLER_V1;
 		} else {
 			dev_err(cdns->dev, "not supported DID=0x%08x\n", state);

drivers/usb/cdns3/drd.h

@@ -193,6 +193,9 @@ struct cdns_otg_irq_regs {
 /* OTGREFCLK - bitmasks */
 #define OTGREFCLK_STB_CLK_SWITCH_EN	BIT(31)
 
+/* SUPS_CTRL - bitmasks */
+#define SUSP_CTRL_SUSPEND_RESIDENCY_ENABLE	BIT(17)
+
 /* OVERRIDE - bitmasks */
 #define OVERRIDE_IDPULLUP		BIT(0)
 /* Only for CDNS3_CONTROLLER_V0 version */