From: Parirajan Muthalagu <parirajan.muthalagu@xxxxxxxxxxxxxx>
Signed-off-by: Parirajan Muthalagu <parirajan.muthalagu@xxxxxxxxxxxxxx>
Signed-off-by: Praveena Nadahally <praveen.nadahally@xxxxxxxxxxxxxx>
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxxxxxx>
---
drivers/usb/gadget/composite.c | 11 ++++++++++-
include/linux/usb/ch9.h | 9 +++++++++
2 files changed, 19 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index e483f80..bfe0bd6 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1074,7 +1074,16 @@ static int composite_bind(struct usb_gadget *gadget)
cdev->bufsiz = USB_BUFSIZ;
cdev->driver = composite;
- usb_gadget_set_selfpowered(gadget);
+ /*
+ * According to USB spec, a device that is actively drawing
+ * more than 100mA from USB must report itself as bus-powered in
+ * the GetStatus(DEVICE) call.
+ * There is no clear mentioning about the status when the device
+ * draws exactly 100mA. so, to be on the safer side, the device is
+ * self-powered only when VBUS is 'less' than 100mA.
+ */
+ if (CONFIG_USB_GADGET_VBUS_DRAW < USB_SELF_POWER_VBUS_MAX_DRAW)
+ usb_gadget_set_selfpowered(gadget);
/* interface and string IDs start at zero via kzalloc.
* we force endpoints to start unassigned; few controller
diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index da2ed77..57cb2a6 100644
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -808,4 +808,13 @@ enum usb_device_state {
*/
};
+/*-------------------------------------------------------------------------*/
+
+/*
+ * USB compliance defines 'less' than 100mA is the maximum
+ * current a device can draw from Host, if it is self-powered.
+ * http://compliance.usb.org/index.asp?UpdateFile=Electrical&Format=Standard#34
+ */
+#define USB_SELF_POWER_VBUS_MAX_DRAW 100
+
#endif /* __LINUX_USB_CH9_H */
--
1.6.3.3
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
