[PATCH 14/14] usb: udc-core: add judgement logic for usb_gadget_connect

[Peter Chen]

On Fri, Mar 15, 2013 at 09:51:29AM +0200, Felipe Balbi wrote:
> 
> that's all wrong and needs to be fixed. UDC-core has to be the central
> point for all these details. We start with the easiest way (call connect
> unconditionally after gadget driver is loaded) and optimize it as we go
> (making sure that there is VBUS before connecting pullups); but we can't
> bypass UDC-core and call usb_gadget_connect() directly from UDC driver.

I have an idea that let the gadget driver call usb_gadget_connect/disconnect,
and make a refcount for calling .pullup at usb_gadget_connect/disconnect.
Below is an initial idea for it, I think it can also cover both udc 
and uvc case.

 drivers/usb/chipidea/udc.c     |    6 ++----
 drivers/usb/gadget/composite.c |    6 ++++++
 include/linux/usb/gadget.h     |   21 +++++++++++++++++++--
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c
index 81184b9..4b6b2d8 100644
--- a/drivers/usb/chipidea/udc.c
+++ b/drivers/usb/chipidea/udc.c
@@ -1386,17 +1386,15 @@ static int ci13xxx_vbus_session(struct usb_gadget *_gadget, int is_active)
 			pm_runtime_get_sync(&_gadget->dev);
 			hw_device_reset(ci, USBMODE_CM_DC);
 			hw_device_state(ci, ci->ep0out->qh.dma);
-			ci13xxx_pullup(_gadget, true);
+			ci->driver->connect(&ci->gadget);
 			dev_dbg(ci->dev, "Connected to host\n");
 		} else {
-			if (ci->driver)
-				ci->driver->disconnect(&ci->gadget);
+			ci->driver->disconnect(&ci->gadget);
 			hw_device_state(ci, 0);
 			if (ci->platdata->notify_event)
 				ci->platdata->notify_event(ci,
 				CI13XXX_CONTROLLER_STOPPED_EVENT);
 			_gadget_stop_activity(&ci->gadget);
-			ci13xxx_pullup(_gadget, false);
 			pm_runtime_put_sync(&_gadget->dev);
 			dev_dbg(ci->dev, "Disconnected from host\n");
 		}
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 7c821de..b7bf5ae 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1479,6 +1479,11 @@ done:
 	return value;
 }
 
+void composite_connect(struct usb_gadget *gadget)
+{
+	usb_gadget_connect(gadget);
+}
+
 void composite_disconnect(struct usb_gadget *gadget)
 {
 	struct usb_composite_dev	*cdev = get_gadget_data(gadget);
@@ -1492,6 +1497,7 @@ void composite_disconnect(struct usb_gadget *gadget)
 		reset_config(cdev);
 	if (cdev->driver->disconnect)
 		cdev->driver->disconnect(cdev);
+	usb_gadget_disconnect(gadget);
 	spin_unlock_irqrestore(&cdev->lock, flags);
 }
 
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 7e373a2..7f7e6bf 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -536,6 +536,7 @@ struct usb_gadget {
 	struct device			dev;
 	unsigned			out_epnum;
 	unsigned			in_epnum;
+	int				connection;
 };
 
 static inline void set_gadget_data(struct usb_gadget *gadget, void *data)
@@ -722,9 +723,16 @@ static inline int usb_gadget_vbus_disconnect(struct usb_gadget *gadget)
  */
 static inline int usb_gadget_connect(struct usb_gadget *gadget)
 {
+	int ret = 0;
 	if (!gadget->ops->pullup)
 		return -EOPNOTSUPP;
-	return gadget->ops->pullup(gadget, 1);
+
+	if (gadget->connection == 0)
+		ret = gadget->ops->pullup(gadget, 1);
+	if (!ret)
+		gadget->connection ++;
+
+	return ret;
 }
 
 /**
@@ -744,9 +752,18 @@ static inline int usb_gadget_connect(struct usb_gadget *gadget)
  */
 static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
 {
+	int ret = 0;
+
 	if (!gadget->ops->pullup)
 		return -EOPNOTSUPP;
-	return gadget->ops->pullup(gadget, 0);
+
+	if (gadget->connection == 1)
+		ret = gadget->ops->pullup(gadget, 0);
+
+	if (!ret)
+		gadget->connection --;
+
+	return ret;
 }
 
> > 
> > In that case, the pullup will not be called, it will check if gadget
> > module is loaded.
> 
> I don't see that in your patch.

At each udc driver, it makes sure it, maybe we can move it to usb_gaget_connect
/usb_gadget_disconnect or its abstract layer.

> > 
> > I am not familiar with SRP, but I think vbus is pre-condition.
> 
> hehe, google SRP.
> 
> Nah, I'll save you the trouble. SRP is a mechanism for the USB
> peripheral to ask the host to enable VBUS. This means that we can keep
> the VBUS charge pump disabled, and thus save power, until peripheral
> requests for a session.

Thanks.

> 
> -- 
> balbi



-- 

Best Regards,
Peter Chen