[PATCH 2/3] usb: common: add helper to get role-switch-default-mode

[Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>]

Add helper to get "role-switch-default-mode", and convert it
to the corresponding enum usb_dr_mode

Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
---
 drivers/usb/common/common.c | 20 ++++++++++++++++++++
 include/linux/usb/otg.h     |  1 +
 2 files changed, 21 insertions(+)

diff --git a/drivers/usb/common/common.c b/drivers/usb/common/common.c
index fff318597337..78a625a4e526 100644
--- a/drivers/usb/common/common.c
+++ b/drivers/usb/common/common.c
@@ -207,6 +207,26 @@ enum usb_dr_mode usb_get_dr_mode(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(usb_get_dr_mode);
 
+/**
+ * usb_get_role_switch_default_mode - Get default mode for given device
+ * @dev: Pointer to the given device
+ *
+ * The function gets string from property 'role-switch-default-mode',
+ * and returns the corresponding enum usb_dr_mode.
+ */
+enum usb_dr_mode usb_get_role_switch_default_mode(struct device *dev)
+{
+	const char *str;
+	int ret;
+
+	ret = device_property_read_string(dev, "role-switch-default-mode", &str);
+	if (ret < 0)
+		return USB_DR_MODE_UNKNOWN;
+
+	return usb_get_dr_mode_from_string(str);
+}
+EXPORT_SYMBOL_GPL(usb_get_role_switch_default_mode);
+
 /**
  * usb_decode_interval - Decode bInterval into the time expressed in 1us unit
  * @epd: The descriptor of the endpoint
diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
index a86ee6aad51b..bde313c97fb6 100644
--- a/include/linux/usb/otg.h
+++ b/include/linux/usb/otg.h
@@ -121,5 +121,6 @@ enum usb_dr_mode {
 };
 
 extern enum usb_dr_mode usb_get_dr_mode(struct device *dev);
+extern enum usb_dr_mode usb_get_role_switch_default_mode(struct device *dev);
 
 #endif /* __LINUX_USB_OTG_H */
-- 
2.18.0