usb: dwc3: st: Fix USB_DR_MODE_PERIPHERAL configuration.

Set USB3_FORCE_VBUSVALID when configured for USB_DR_MODE_PERIPHERAL
mode, as it is required to have a working setup.

This worked on the internal driver by relying on the reset
value of the syscfg register as the bits aren't explicity cleared
and set like the upstream driver.

Also add a comment about what setting this bit means.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc3/dwc3-st.c b/drivers/usb/dwc3/dwc3-st.c
index 5c0adb9c6fb27baa778615f17705ac6ab7896079..50d6ae6f88bc336a8631ce76f9c45c8de077b481 100644 (file)
--- a/drivers/usb/dwc3/dwc3-st.c
+++ b/drivers/usb/dwc3/dwc3-st.c
@@ -129,12 +129,18 @@ static int st_dwc3_drd_init(struct st_dwc3 *dwc3_data)
        switch (dwc3_data->dr_mode) {
        case USB_DR_MODE_PERIPHERAL:
 
-               val &= ~(USB3_FORCE_VBUSVALID | USB3_DELAY_VBUSVALID
+               val &= ~(USB3_DELAY_VBUSVALID
                        | USB3_SEL_FORCE_OPMODE | USB3_FORCE_OPMODE(0x3)
                        | USB3_SEL_FORCE_DPPULLDOWN2 | USB3_FORCE_DPPULLDOWN2
                        | USB3_SEL_FORCE_DMPULLDOWN2 | USB3_FORCE_DMPULLDOWN2);
 
-               val |= USB3_DEVICE_NOT_HOST;
+               /*
+                * USB3_PORT2_FORCE_VBUSVALID When '1' and when
+                * USB3_PORT2_DEVICE_NOT_HOST = 1, forces VBUSVLDEXT2 input
+                * of the pico PHY to 1.
+                */
+
+               val |= USB3_DEVICE_NOT_HOST | USB3_FORCE_VBUSVALID;
                break;
 
        case USB_DR_MODE_HOST: