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>

1 files changed, 18 insertions, 13 deletions

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 0b92e982ac54..113ec80dcc26 100644
--- 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);
         }