usb: dwc2: gadget: Program GREFCLK register

Added dwc2_gadget_program_ref_clk function to program GREFCLK
register in device mode.
Acked-by: Minas Harutyunyan <hminas@synopsys.com>
Signed-off-by: Grigor Tovmasyan <tovmasya@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/dwc2/core.h

@@ -1381,6 +1381,7 @@ int dwc2_hsotg_tx_fifo_count(struct dwc2_hsotg *hsotg);
 int dwc2_hsotg_tx_fifo_total_depth(struct dwc2_hsotg *hsotg);
 int dwc2_hsotg_tx_fifo_average_depth(struct dwc2_hsotg *hsotg);
 void dwc2_gadget_init_lpm(struct dwc2_hsotg *hsotg);
+void dwc2_gadget_program_ref_clk(struct dwc2_hsotg *hsotg);
 #else
 static inline int dwc2_hsotg_remove(struct dwc2_hsotg *dwc2)
 { return 0; }
@@ -1415,6 +1416,7 @@ static inline int dwc2_hsotg_tx_fifo_total_depth(struct dwc2_hsotg *hsotg)
 static inline int dwc2_hsotg_tx_fifo_average_depth(struct dwc2_hsotg *hsotg)
 { return 0; }
 static inline void dwc2_gadget_init_lpm(struct dwc2_hsotg *hsotg) {}
+static inline void dwc2_gadget_program_ref_clk(struct dwc2_hsotg *hsotg) {}
 #endif
 
 #if IS_ENABLED(CONFIG_USB_DWC2_HOST) || IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)

drivers/usb/dwc2/gadget.c

@@ -3418,6 +3418,10 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 	/* configure the core to support LPM */
 	dwc2_gadget_init_lpm(hsotg);
 
+	/* program GREFCLK register if needed */
+	if (using_desc_dma(hsotg) && hsotg->params.service_interval)
+		dwc2_gadget_program_ref_clk(hsotg);
+
 	/* must be at-least 3ms to allow bus to see disconnect */
 	mdelay(3);
 
@@ -5001,6 +5005,25 @@ void dwc2_gadget_init_lpm(struct dwc2_hsotg *hsotg)
 	dev_dbg(hsotg->dev, "GLPMCFG=0x%08x\n", dwc2_readl(hsotg, GLPMCFG));
 }
 
+/**
+ * dwc2_gadget_program_ref_clk - Program GREFCLK register in device mode
+ *
+ * @hsotg: Programming view of DWC_otg controller
+ *
+ */
+void dwc2_gadget_program_ref_clk(struct dwc2_hsotg *hsotg)
+{
+	u32 val = 0;
+
+	val |= GREFCLK_REF_CLK_MODE;
+	val |= hsotg->params.ref_clk_per << GREFCLK_REFCLKPER_SHIFT;
+	val |= hsotg->params.sof_cnt_wkup_alert <<
+	       GREFCLK_SOF_CNT_WKUP_ALERT_SHIFT;
+
+	dwc2_writel(hsotg, val, GREFCLK);
+	dev_dbg(hsotg->dev, "GREFCLK=0x%08x\n", dwc2_readl(hsotg, GREFCLK));
+}
+
 /**
  * dwc2_gadget_enter_hibernation() - Put controller in Hibernation.
  *