SAMV7 USB device: Finish option to force full speed mdoe

arch/arm/src/samv7/Kconfig

@@ -1253,6 +1253,19 @@ endmenu # EMAC0 device driver options
 menu "USB High Speed Device Controller driver (DCD) options"
 	depends on SAMV7_USBDEVHS
 
+config SAMV7_USBDEVHS_LOWPOWER
+	bool "Low-power mode"
+	default n
+	depends on EXPERIMENTAL
+	---help---
+		The USBHS can work in two modes:
+
+		- Normal mode where High speed, Full speed and Low speed are
+		  available.
+		- Low-power mode where only Full speed and Low speed are available.
+
+		This options selects the low-power mode.
+
 config SAMV7_USBHS_SCATTERGATHER
 	bool
 	default n

arch/arm/src/samv7/sam_clockconfig.c

@@ -59,11 +59,6 @@
 /****************************************************************************
  * Pre-processor Definitions
  ****************************************************************************/
-/* Configuration ***********************************************************/
-/* Not yet supported */
-
-#undef CONFIG_SAMV7_USBDEVHS_LOWPOWER
-
 /* Board Settings **********************************************************/
 /* PMC register settings based on the board configuration values defined
  * in board.h

arch/arm/src/samv7/sam_usbdevhs.c

@@ -4141,7 +4141,7 @@ static int sam_pullup(FAR struct usbdev_s *dev, bool enable)
       /* Un-freeze clocking.
        *
        * When the clock is frozen, on certain bits in the USBCH_CTRL
-       * register can be modified (FRZCLK, USBE, and LS).  In addtion,
+       * register can be modified (FRZCLK, USBE, and LS).  In addition,
        * only the asynchronous interrupt sources can trigger the USB
        * interrupt:
        *
@@ -4357,20 +4357,24 @@ static void sam_hw_setup(struct sam_usbdev_s *priv)
    * unfreeze clocking (FRZCLK = 0)
    */
 
-  regval |= USBHS_CTRL_USBE;
+  regval |= USBHS_CTRL_UIMOD_DEVICE;
   sam_putreg(regval, SAM_USBHS_CTRL);
 
-  regval |= USBHS_CTRL_UIMOD_DEVICE;
+  regval |= USBHS_CTRL_USBE;
   sam_putreg(regval, SAM_USBHS_CTRL);
 
   regval &= ~USBHS_CTRL_FRZCLK;
   sam_putreg(regval, SAM_USBHS_CTRL);
 
-  /* Select High Speed */
+  /* Select High Speed or force Full Speed */
 
   regval  = sam_getreg(SAM_USBHS_DEVCTRL);
   regval &= ~USBHS_DEVCTRL_SPDCONF_MASK;
+#ifdef CONFIG_SAMV7_USBDEVHS_LOWPOWER
+  regval |= USBHS_DEVCTRL_SPDCONF_LOWPOWER;
+#else
   regval |= USBHS_DEVCTRL_SPDCONF_NORMAL;
+#endif
   sam_putreg(regval, SAM_USBHS_DEVCTRL);
 
   /* Wait for UTMI clocking to be usable */
@@ -4383,7 +4387,7 @@ static void sam_hw_setup(struct sam_usbdev_s *priv)
   regval &= ~USBHS_DEVCTRL_LS;
   sam_putreg(regval, SAM_USBHS_DEVCTRL);
 
-  /* Reset and disable all endpoints, initializing endpoint 0. */
+  /* Reset and disable all endpoints, re-initializing endpoint 0. */
 
   sam_epset_reset(priv, SAM_EPSET_ALL);
   sam_ep0_configure(priv);