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Date: Mon, 24 Aug 2015 16:21:23 +0300
From: Roger Quadros <rogerq@...com>
To: <stern@...land.harvard.edu>, <balbi@...com>,
<gregkh@...uxfoundation.org>, <peter.chen@...escale.com>
CC: <dan.j.williams@...el.com>, <jun.li@...escale.com>,
<mathias.nyman@...ux.intel.com>, <tony@...mide.com>,
<Joao.Pinto@...opsys.com>, <abrestic@...omium.org>,
<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-omap@...r.kernel.org>, Roger Quadros <rogerq@...com>
Subject: [PATCH v4 12/13] usb: gadget: udc: adapt to OTG core
The OTG state machine needs a mechanism to start and
stop the gadget controller. Add usb_gadget_start()
and usb_gadget_stop().
Register with OTG core when gadget function driver
is available and unregister when function driver is unbound.
We need to unlock the usb_lock mutexbefore calling
usb_otg_register_gadget() in udc_bind_to_driver() and
usb_gadget_remove_driver() else it will cause a circular
locking dependency.
Ignore softconnect sysfs control when we're in OTG
mode as OTG FSM takes care of gadget softconnect using
the b_bus_req mechanism.
Signed-off-by: Roger Quadros <rogerq@...com>
---
drivers/usb/gadget/udc/udc-core.c | 124 +++++++++++++++++++++++++++++++++++---
1 file changed, 114 insertions(+), 10 deletions(-)
diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
index f660afb..e961668 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -28,6 +28,7 @@
#include <linux/usb/ch9.h>
#include <linux/usb/gadget.h>
#include <linux/usb.h>
+#include <linux/usb/otg.h>
/**
* struct usb_udc - describes one usb device controller
@@ -37,6 +38,7 @@
* @list - for use by the udc class driver
* @vbus - for udcs who care about vbus status, this value is real vbus status;
* for udcs who do not care about vbus status, this value is always true
+ * @is_otg - we're registered with OTG core and it takes care of UDC start/stop
*
* This represents the internal data structure which is used by the UDC-class
* to hold information about udc driver and gadget together.
@@ -47,6 +49,7 @@ struct usb_udc {
struct device dev;
struct list_head list;
bool vbus;
+ bool is_otg;
};
static struct class *udc_class;
@@ -300,6 +303,7 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
*/
static inline int usb_gadget_udc_start(struct usb_udc *udc)
{
+ dev_dbg(&udc->dev, "%s\n", __func__);
return udc->gadget->ops->udc_start(udc->gadget, udc->driver);
}
@@ -317,10 +321,81 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc)
*/
static inline void usb_gadget_udc_stop(struct usb_udc *udc)
{
+ dev_dbg(&udc->dev, "%s\n", __func__);
udc->gadget->ops->udc_stop(udc->gadget);
}
/**
+ * usb_gadget_start - start the usb gadget controller and connect to bus
+ * @gadget: the gadget device to start
+ *
+ * This is external API for use by OTG core.
+ *
+ * Start the usb device controller and connect to bus (enable pull).
+ */
+static int usb_gadget_start(struct usb_gadget *gadget)
+{
+ int ret;
+ struct usb_udc *udc = NULL;
+
+ dev_dbg(&gadget->dev, "%s\n", __func__);
+ mutex_lock(&udc_lock);
+ list_for_each_entry(udc, &udc_list, list)
+ if (udc->gadget == gadget)
+ goto found;
+
+ dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
+ __func__);
+ mutex_unlock(&udc_lock);
+ return -EINVAL;
+
+found:
+ ret = usb_gadget_udc_start(udc);
+ if (ret)
+ dev_err(&udc->dev, "USB Device Controller didn't start: %d\n",
+ ret);
+ else
+ usb_udc_connect_control(udc);
+
+ mutex_unlock(&udc_lock);
+
+ return ret;
+}
+
+/**
+ * usb_gadget_stop - disconnect from bus and stop the usb gadget
+ * @gadget: The gadget device we want to stop
+ *
+ * This is external API for use by OTG core.
+ *
+ * Disconnect from the bus (disable pull) and stop the
+ * gadget controller.
+ */
+static int usb_gadget_stop(struct usb_gadget *gadget)
+{
+ struct usb_udc *udc = NULL;
+
+ dev_dbg(&gadget->dev, "%s\n", __func__);
+ mutex_lock(&udc_lock);
+ list_for_each_entry(udc, &udc_list, list)
+ if (udc->gadget == gadget)
+ goto found;
+
+ dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
+ __func__);
+ mutex_unlock(&udc_lock);
+ return -EINVAL;
+
+found:
+ usb_gadget_disconnect(udc->gadget);
+ udc->driver->disconnect(udc->gadget);
+ usb_gadget_udc_stop(udc);
+ mutex_unlock(&udc_lock);
+
+ return 0;
+}
+
+/**
* usb_udc_release - release the usb_udc struct
* @dev: the dev member within usb_udc
*
@@ -438,6 +513,7 @@ int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget)
}
EXPORT_SYMBOL_GPL(usb_add_gadget_udc);
+/* udc_lock must be held */
static void usb_gadget_remove_driver(struct usb_udc *udc)
{
dev_dbg(&udc->dev, "unregistering UDC driver [%s]\n",
@@ -445,10 +521,18 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
- usb_gadget_disconnect(udc->gadget);
- udc->driver->disconnect(udc->gadget);
+ /* If OTG, the otg core ensures UDC is stopped on unregister */
+ if (udc->is_otg) {
+ mutex_unlock(&udc_lock);
+ usb_otg_unregister_gadget(udc->gadget);
+ mutex_lock(&udc_lock);
+ } else {
+ usb_gadget_disconnect(udc->gadget);
+ udc->driver->disconnect(udc->gadget);
+ usb_gadget_udc_stop(udc);
+ }
+
udc->driver->unbind(udc->gadget);
- usb_gadget_udc_stop(udc);
udc->driver = NULL;
udc->dev.driver = NULL;
@@ -473,11 +557,12 @@ void usb_del_gadget_udc(struct usb_gadget *gadget)
mutex_lock(&udc_lock);
list_del(&udc->list);
- mutex_unlock(&udc_lock);
if (udc->driver)
usb_gadget_remove_driver(udc);
+ mutex_unlock(&udc_lock);
+
kobject_uevent(&udc->dev.kobj, KOBJ_REMOVE);
flush_work(&gadget->work);
device_unregister(&udc->dev);
@@ -487,6 +572,12 @@ EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
/* ------------------------------------------------------------------------- */
+struct otg_gadget_ops otg_gadget_intf = {
+ .start = usb_gadget_start,
+ .stop = usb_gadget_stop,
+};
+
+/* udc_lock must be held */
static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *driver)
{
int ret;
@@ -501,12 +592,19 @@ static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *dri
ret = driver->bind(udc->gadget, driver);
if (ret)
goto err1;
- ret = usb_gadget_udc_start(udc);
- if (ret) {
- driver->unbind(udc->gadget);
- goto err1;
+
+ /* If OTG, the otg core starts the UDC when needed */
+ mutex_unlock(&udc_lock);
+ udc->is_otg = !usb_otg_register_gadget(udc->gadget, &otg_gadget_intf);
+ mutex_lock(&udc_lock);
+ if (!udc->is_otg) {
+ ret = usb_gadget_udc_start(udc);
+ if (ret) {
+ driver->unbind(udc->gadget);
+ goto err1;
+ }
+ usb_udc_connect_control(udc);
}
- usb_udc_connect_control(udc);
kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
return 0;
@@ -618,9 +716,15 @@ static ssize_t usb_udc_softconn_store(struct device *dev,
return -EOPNOTSUPP;
}
+ /* In OTG mode we don't support softconnect, but b_bus_req */
+ if (udc->is_otg) {
+ dev_err(dev, "soft-connect not supported in OTG mode\n");
+ return -EOPNOTSUPP;
+ }
+
if (sysfs_streq(buf, "connect")) {
usb_gadget_udc_start(udc);
- usb_gadget_connect(udc->gadget);
+ usb_udc_connect_control(udc);
} else if (sysfs_streq(buf, "disconnect")) {
usb_gadget_disconnect(udc->gadget);
udc->driver->disconnect(udc->gadget);
--
2.1.4
--
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