[PATCH] usb: dwc3: Addition of "dr_mode" dt property.

[Ruchika Kharwar <ruchika@ti.com>]

This patch adds an optional parameter "dr_mode" to the dwc3 core device node.
In the case the compile flag for the DWC3 controller is set to
"USB_DWC3_DUAL_ROLE" a device tree could restrain to either functionality of
host or gadget. In the case the device tree does not use this optional flag or
specifies it superfluously to "drd" the functionality will be that
of a dual role device.

Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
---
 Documentation/devicetree/bindings/usb/dwc3.txt |    3 ++-
 drivers/usb/dwc3/core.c                        |   21 +++++++++++++++++----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
index 7a95c65..2f5d584 100644
--- a/Documentation/devicetree/bindings/usb/dwc3.txt
+++ b/Documentation/devicetree/bindings/usb/dwc3.txt
@@ -10,7 +10,8 @@ Required properties:
 
 Optional properties:
  - tx-fifo-resize: determines if the FIFO *has* to be reallocated.
-
+ - dr_mode: determines the mode of core. Supported modes are "gadget", "host"
+   and "drd".
 This is usually a subnode to DWC3 glue to which it is connected.
 
 dwc3@4a030000 {
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index c35d49d..e11660a 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -378,7 +378,7 @@ static int dwc3_probe(struct platform_device *pdev)
 	void			*mem;
 
 	u8			mode;
-
+	char			*dr_mode;
 	mem = devm_kzalloc(dev, sizeof(*dwc) + DWC3_ALIGN_MASK, GFP_KERNEL);
 	if (!mem) {
 		dev_err(dev, "not enough memory\n");
@@ -520,9 +520,22 @@ static int dwc3_probe(struct platform_device *pdev)
 		mode = DWC3_MODE_HOST;
 	else if (IS_ENABLED(CONFIG_USB_DWC3_GADGET))
 		mode = DWC3_MODE_DEVICE;
-	else
-		mode = DWC3_MODE_DRD;
-
+	else {
+		if (of_property_read_string(node, "dr_mode", &dr_mode))
+			mode = DWC3_MODE_DRD;
+		else {
+			if (strcmp(dr_mode, "host") == 0)
+				mode = DWC3_MODE_HOST;
+			else if (strcmp(dr_mode, "gadget") == 0)
+				mode = DWC3_MODE_DEVICE;
+			else if (strcmp(dr_mode, "drd") == 0)
+				mode = DWC3_MODE_DRD;
+			else {
+				dev_err(dev, "invalid dr_mode property value\n");
+				goto err2;
+			}
+		}
+	}
 	switch (mode) {
 	case DWC3_MODE_DEVICE:
 		dwc3_set_mode(dwc, DWC3_GCTL_PRTCAP_DEVICE);
-- 
1.7.5.4