[PATCH v2] usb/gadget: make composite gadget meet usb compliance for vbus draw

[Du, Changbin]

USB-IF compliance requirement limits the vbus current according to
current state. USB2 Spec requires that un-configured current must
be <= 100mA, for USB3 is 150mA, OTG is 2.5mA. So set corresponding
vbus draw current according to device mode.

Signed-off-by: Du, Changbin <changbin.du@xxxxxxxxx>
---
Resend patch since no response for 4 weeks, probably bee missed.
Changes from v1:
	Also update configfs to use new api composite_reset.

---
 drivers/usb/gadget/composite.c | 39 ++++++++++++++++++++++++++++++++-------
 drivers/usb/gadget/configfs.c  |  2 +-
 include/linux/usb/composite.h  |  1 +
 include/uapi/linux/usb/ch9.h   |  9 +++++++++
 4 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 4e3447b..b3896e9 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -610,6 +610,21 @@ static void device_qual(struct usb_composite_dev *cdev)
 	qual->bRESERVED = 0;
 }
 
+static unsigned unconfigured_vbus_draw(struct usb_composite_dev *cdev)
+{
+	struct usb_gadget *g = cdev->gadget;
+	unsigned power;
+
+	if (gadget_is_otg(g))
+		power = USB_OTG_UNCONF_STATE_VBUS_MAX_DRAW;
+	else if (g->speed == USB_SPEED_SUPER)
+		power = USB3_UNCONF_STATE_VBUS_MAX_DRAW;
+	else
+		power = USB2_UNCONF_STATE_VBUS_MAX_DRAW;
+
+	return power;
+}
+
 /*-------------------------------------------------------------------------*/
 
 static void reset_config(struct usb_composite_dev *cdev)
@@ -634,7 +649,7 @@ static int set_config(struct usb_composite_dev *cdev,
 	struct usb_gadget	*gadget = cdev->gadget;
 	struct usb_configuration *c = NULL;
 	int			result = -EINVAL;
-	unsigned		power = gadget_is_otg(gadget) ? 8 : 100;
+	unsigned		power = unconfigured_vbus_draw(cdev);
 	int			tmp;
 
 	if (number) {
@@ -1829,6 +1844,15 @@ done:
 	return value;
 }
 
+void composite_reset(struct usb_gadget *gadget)
+{
+	struct usb_composite_dev *cdev = get_gadget_data(gadget);
+
+	DBG(cdev, "reset\n");
+	usb_gadget_vbus_draw(gadget, unconfigured_vbus_draw(cdev));
+	composite_disconnect(gadget);
+}
+
 void composite_disconnect(struct usb_gadget *gadget)
 {
 	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
@@ -2095,7 +2119,7 @@ void composite_suspend(struct usb_gadget *gadget)
 
 	cdev->suspended = 1;
 
-	usb_gadget_vbus_draw(gadget, 2);
+	usb_gadget_vbus_draw(gadget, USB_SUSPEND_STATE_VBUS_MAX_DRAW);
 }
 
 void composite_resume(struct usb_gadget *gadget)
@@ -2117,10 +2141,11 @@ void composite_resume(struct usb_gadget *gadget)
 		}
 
 		maxpower = cdev->config->MaxPower;
-
-		usb_gadget_vbus_draw(gadget, maxpower ?
-			maxpower : CONFIG_USB_GADGET_VBUS_DRAW);
-	}
+		if (!maxpower)
+			maxpower = CONFIG_USB_GADGET_VBUS_DRAW;
+	} else
+		maxpower = unconfigured_vbus_draw(cdev);
+	usb_gadget_vbus_draw(gadget, maxpower);
 
 	cdev->suspended = 0;
 }
@@ -2132,7 +2157,7 @@ static const struct usb_gadget_driver composite_driver_template = {
 	.unbind		= composite_unbind,
 
 	.setup		= composite_setup,
-	.reset		= composite_disconnect,
+	.reset		= composite_reset,
 	.disconnect	= composite_disconnect,
 
 	.suspend	= composite_suspend,
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 0495c94..e16335d 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -1449,7 +1449,7 @@ static const struct usb_gadget_driver configfs_driver_template = {
 	.unbind         = configfs_composite_unbind,
 
 	.setup          = composite_setup,
-	.reset          = composite_disconnect,
+	.reset          = composite_reset,
 	.disconnect     = composite_disconnect,
 
 	.suspend	= composite_suspend,
diff --git a/include/linux/usb/composite.h b/include/linux/usb/composite.h
index 2511469..825ad39 100644
--- a/include/linux/usb/composite.h
+++ b/include/linux/usb/composite.h
@@ -506,6 +506,7 @@ extern struct usb_string *usb_gstrings_attach(struct usb_composite_dev *cdev,
 
 extern int usb_string_ids_n(struct usb_composite_dev *c, unsigned n);
 
+extern void composite_reset(struct usb_gadget *gadget);
 extern void composite_disconnect(struct usb_gadget *gadget);
 extern int composite_setup(struct usb_gadget *gadget,
 		const struct usb_ctrlrequest *ctrl);
diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
index aa33fd1..ab216bf 100644
--- a/include/uapi/linux/usb/ch9.h
+++ b/include/uapi/linux/usb/ch9.h
@@ -996,4 +996,13 @@ struct usb_set_sel_req {
  */
 #define USB_SELF_POWER_VBUS_MAX_DRAW		100
 
+/*
+ * USB2 compliance requires that un-configured current draw less than 100mA,
+ * while USB3 requires it <= 150mA, and OTG device requires it <= 2.5mA.
+ */
+#define USB2_UNCONF_STATE_VBUS_MAX_DRAW		100
+#define USB3_UNCONF_STATE_VBUS_MAX_DRAW		150
+#define USB_OTG_UNCONF_STATE_VBUS_MAX_DRAW	2
+#define USB_SUSPEND_STATE_VBUS_MAX_DRAW		2
+
 #endif /* _UAPI__LINUX_USB_CH9_H */
-- 
2.1.4

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