usb: renesas_usbhs: add suspend event support in gadget mode

When R-Car Gen3 USB 2.0 is in Gadget mode, if host is detached an interrupt
will be generated and Suspended state bit is set in interrupt status
register. Interrupt handler will call driver->suspend(composite_suspend)
if suspended state bit is set. composite_suspend will call
ffs_func_suspend which will post FUNCTIONFS_SUSPEND and will be consumed
by user space application via /dev/ep0.

To be able to detect host detach, extend the DVSQ_MASK to cover the
Suspended bit of the DVSQ[2:0] bitfield from the Interrupt Status
Register 0 (INTSTS0) register and perform appropriate action in the
DVST interrupt handler (usbhsg_irq_dev_state).

Without this commit, disconnection of the phone from R-Car-H3 ES2.0
Salvator-X CN9 port is not recognized and reverse role switch does
not happen. If phone is connected again it does not enumerate.

With this commit, disconnection will be recognized and reverse role
switch will happen by a user space application. If phone is connected
again it will enumerate properly and will become visible in the output
of 'lsusb'.

Signed-off-by: Veeraiyan Chidambaram <[e-mail]>
Signed-off-by: Eugeniu Rosca <[e-mail]>
Reviewed-by: Yoshihiro Shimoda <[e-mail]>
Tested-by: Yoshihiro Shimoda <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/renesas_usbhs/common.h

···
 #define VBSTS	(1 << 7)	/* VBUS_0 and VBUSIN_0 Input Status */
 #define VALID	(1 << 3)	/* USB Request Receive */
 
-#define DVSQ_MASK		(0x3 << 4)	/* Device State */
+#define DVSQ_MASK		(0x7 << 4)	/* Device State */
 #define  POWER_STATE		(0 << 4)
 #define  DEFAULT_STATE		(1 << 4)
 #define  ADDRESS_STATE		(2 << 4)
 #define  CONFIGURATION_STATE	(3 << 4)
+#define  SUSPENDED_STATE	(4 << 4)
 
 #define CTSQ_MASK		(0x7)	/* Control Transfer Stage */
 #define  IDLE_SETUP_STAGE	0	/* Idle stage or setup stage */

drivers/usb/renesas_usbhs/mod_gadget.c

···
 {
 	struct usbhsg_gpriv *gpriv = usbhsg_priv_to_gpriv(priv);
 	struct device *dev = usbhsg_gpriv_to_dev(gpriv);
+	int state = usbhs_status_get_device_state(irq_state);
 
 	gpriv->gadget.speed = usbhs_bus_get_speed(priv);
 
-	dev_dbg(dev, "state = %x : speed : %d\n",
-		usbhs_status_get_device_state(irq_state),
-		gpriv->gadget.speed);
+	dev_dbg(dev, "state = %x : speed : %d\n", state, gpriv->gadget.speed);
+
+	if (gpriv->gadget.speed != USB_SPEED_UNKNOWN &&
+	    (state & SUSPENDED_STATE)) {
+		if (gpriv->driver && gpriv->driver->suspend)
+			gpriv->driver->suspend(&gpriv->gadget);
+		usb_gadget_set_state(&gpriv->gadget, USB_STATE_SUSPENDED);
+	}
 
 	return 0;
 }