usb: dwc3: Enable usb2 LPM only when connected as usb2.0

Synopsys says:
The HIRD Threshold field must be set to ‘0’ when the device core is
operating in super speed mode.

This patch implements above statement.

Cc: <stable@vger.kernel.org> # v3.6 v3.7 v3.8
Acked-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 0b92e98..113ec80 100644 (file)
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2154,6 +2154,23 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
                break;
        }
 
+       /* Enable USB2 LPM Capability */
+
+       if ((dwc->revision > DWC3_REVISION_194A)
+                       && (speed != DWC3_DCFG_SUPERSPEED)) {
+               reg = dwc3_readl(dwc->regs, DWC3_DCFG);
+               reg |= DWC3_DCFG_LPM_CAP;
+               dwc3_writel(dwc->regs, DWC3_DCFG, reg);
+
+               reg = dwc3_readl(dwc->regs, DWC3_DCTL);
+               reg &= ~(DWC3_DCTL_HIRD_THRES_MASK | DWC3_DCTL_L1_HIBER_EN);
+
+               /* TODO: This should be configurable */
+               reg |= DWC3_DCTL_HIRD_THRES(28);
+
+               dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+       }
+
        /* Recent versions support automatic phy suspend and don't need this */
        if (dwc->revision < DWC3_REVISION_194A) {
                /* Suspend unneeded PHY */
@@ -2460,20 +2477,8 @@ int dwc3_gadget_init(struct dwc3 *dwc)
                        DWC3_DEVTEN_DISCONNEVTEN);
        dwc3_writel(dwc->regs, DWC3_DEVTEN, reg);
 
-       /* Enable USB2 LPM and automatic phy suspend only on recent versions */
+       /* automatic phy suspend only on recent versions */
        if (dwc->revision >= DWC3_REVISION_194A) {
-               reg = dwc3_readl(dwc->regs, DWC3_DCFG);
-               reg |= DWC3_DCFG_LPM_CAP;
-               dwc3_writel(dwc->regs, DWC3_DCFG, reg);
-
-               reg = dwc3_readl(dwc->regs, DWC3_DCTL);
-               reg &= ~(DWC3_DCTL_HIRD_THRES_MASK | DWC3_DCTL_L1_HIBER_EN);
-
-               /* TODO: This should be configurable */
-               reg |= DWC3_DCTL_HIRD_THRES(28);
-
-               dwc3_writel(dwc->regs, DWC3_DCTL, reg);
-
                dwc3_gadget_usb2_phy_suspend(dwc, false);
                dwc3_gadget_usb3_phy_suspend(dwc, false);
        }