USB: gpio_vbus: avoid consecutive vbus_session calls with the same "is_active"
Basically, ->vbus_session() calls should be served when VBUS session
starts and ends (it's not whenever transciever drivers detect VBUS
_changes_). Otherwise, if UDC gadget drivers don't want for some
reason ->vbus_session() calls with the same "is_active" value, either
OTG or UDC drivers need to have some protection handlings.
Also, on platforms using this 'gpio_vbus' driver, the driver is only
allowed to check whether VBUS is applied. There is no kernel-standard
way prepared for UDC gadget drivers to do that.
With this in mind, gpio_vbus should try to prevent unnecessary
consecutive vbus_session calls being served with the same "in_active"
value.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/otg/gpio_vbus.c b/drivers/usb/otg/gpio_vbus.c
index ac962ac..bd6e755 100644
--- a/drivers/usb/otg/gpio_vbus.c
+++ b/drivers/usb/otg/gpio_vbus.c
@@ -38,6 +38,7 @@
int vbus_draw_enabled;
unsigned mA;
struct delayed_work work;
+ int vbus;
};
@@ -96,18 +97,24 @@
struct gpio_vbus_data *gpio_vbus =
container_of(work, struct gpio_vbus_data, work.work);
struct gpio_vbus_mach_info *pdata = gpio_vbus->dev->platform_data;
- int gpio, status;
+ int gpio, status, vbus;
if (!gpio_vbus->phy.otg->gadget)
return;
+ vbus = is_vbus_powered(pdata);
+ if ((vbus ^ gpio_vbus->vbus) == 0)
+ return;
+ gpio_vbus->vbus = vbus;
+
/* Peripheral controllers which manage the pullup themselves won't have
* gpio_pullup configured here. If it's configured here, we'll do what
* isp1301_omap::b_peripheral() does and enable the pullup here... although
* that may complicate usb_gadget_{,dis}connect() support.
*/
gpio = pdata->gpio_pullup;
- if (is_vbus_powered(pdata)) {
+
+ if (vbus) {
status = USB_EVENT_VBUS;
gpio_vbus->phy.state = OTG_STATE_B_PERIPHERAL;
gpio_vbus->phy.last_event = status;
@@ -195,6 +202,7 @@
dev_dbg(&pdev->dev, "registered gadget '%s'\n", gadget->name);
/* initialize connection state */
+ gpio_vbus->vbus = 0; /* start with disconnected */
gpio_vbus_irq(irq, pdev);
return 0;
}