usb: dwc3: add dual role support using OTG block

This is useful on platforms (e.g. TI AM437x) that don't
have ID available on a GPIO but do have the OTG block.

We can obtain the ID state via the OTG block and use it
for dual-role switching.

Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

1 files changed, 57 insertions, 10 deletions

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index b014c87a7319..e8890c0201a5 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -89,10 +89,7 @@ static int dwc3_get_dr_mode(struct dwc3 *dwc)
 	return 0;
 }
 
-static void dwc3_event_buffers_cleanup(struct dwc3 *dwc);
-static int dwc3_event_buffers_setup(struct dwc3 *dwc);
-
-static void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode)
+void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode)
 {
 	u32 reg;
 
@@ -110,16 +107,19 @@ static void __dwc3_set_mode(struct work_struct *work)
 	unsigned long flags;
 	int ret;
 
-	if (!dwc->desired_dr_role)
+	if (dwc->dr_mode != USB_DR_MODE_OTG)
 		return;
 
-	if (dwc->desired_dr_role == dwc->current_dr_role)
+	if (dwc->current_dr_role == DWC3_GCTL_PRTCAP_OTG)
+		dwc3_otg_update(dwc, 0);
+
+	if (!dwc->desired_dr_role)
 		return;
 
-	if (dwc->dr_mode != USB_DR_MODE_OTG)
+	if (dwc->desired_dr_role == dwc->current_dr_role)
 		return;
 
-	if (dwc->desired_dr_role == DWC3_GCTL_PRTCAP_OTG)
+	if (dwc->desired_dr_role == DWC3_GCTL_PRTCAP_OTG && dwc->edev)
 		return;
 
 	switch (dwc->current_dr_role) {
@@ -130,6 +130,13 @@ static void __dwc3_set_mode(struct work_struct *work)
 		dwc3_gadget_exit(dwc);
 		dwc3_event_buffers_cleanup(dwc);
 		break;
+	case DWC3_GCTL_PRTCAP_OTG:
+		dwc3_otg_exit(dwc);
+		spin_lock_irqsave(&dwc->lock, flags);
+		dwc->desired_otg_role = DWC3_OTG_ROLE_IDLE;
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		dwc3_otg_update(dwc, 1);
+		break;
 	default:
 		break;
 	}
@@ -165,9 +172,14 @@ static void __dwc3_set_mode(struct work_struct *work)
 		if (ret)
 			dev_err(dwc->dev, "failed to initialize peripheral\n");
 		break;
+	case DWC3_GCTL_PRTCAP_OTG:
+		dwc3_otg_init(dwc);
+		dwc3_otg_update(dwc, 0);
+		break;
 	default:
 		break;
 	}
+
 }
 
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
@@ -351,7 +363,7 @@ static int dwc3_alloc_event_buffers(struct dwc3 *dwc, unsigned length)
  *
  * Returns 0 on success otherwise negative errno.
  */
-static int dwc3_event_buffers_setup(struct dwc3 *dwc)
+int dwc3_event_buffers_setup(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer	*evt;
 
@@ -368,7 +380,7 @@ static int dwc3_event_buffers_setup(struct dwc3 *dwc)
 	return 0;
 }
 
-static void dwc3_event_buffers_cleanup(struct dwc3 *dwc)
+void dwc3_event_buffers_cleanup(struct dwc3 *dwc)
 {
 	struct dwc3_event_buffer	*evt;
 
@@ -1329,6 +1341,20 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 		if (!PMSG_IS_AUTO(msg))
 			dwc3_core_exit(dwc);
 		break;
+	case DWC3_GCTL_PRTCAP_OTG:
+		/* do nothing during runtime_suspend */
+		if (PMSG_IS_AUTO(msg))
+			break;
+
+		if (dwc->current_otg_role == DWC3_OTG_ROLE_DEVICE) {
+			spin_lock_irqsave(&dwc->lock, flags);
+			dwc3_gadget_suspend(dwc);
+			spin_unlock_irqrestore(&dwc->lock, flags);
+		}
+
+		dwc3_otg_exit(dwc);
+		dwc3_core_exit(dwc);
+		break;
 	default:
 		/* do nothing */
 		break;
@@ -1360,6 +1386,27 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
 				return ret;
 		}
 		break;
+	case DWC3_GCTL_PRTCAP_OTG:
+		/* nothing to do on runtime_resume */
+		if (PMSG_IS_AUTO(msg))
+			break;
+
+		ret = dwc3_core_init(dwc);
+		if (ret)
+			return ret;
+
+		dwc3_set_prtcap(dwc, dwc->current_dr_role);
+
+		dwc3_otg_init(dwc);
+		if (dwc->current_otg_role == DWC3_OTG_ROLE_HOST) {
+			dwc3_otg_host_init(dwc);
+		} else if (dwc->current_otg_role == DWC3_OTG_ROLE_DEVICE) {
+			spin_lock_irqsave(&dwc->lock, flags);
+			dwc3_gadget_resume(dwc);
+			spin_unlock_irqrestore(&dwc->lock, flags);
+		}
+
+		break;
 	default:
 		/* do nothing */
 		break;