[PATCH 09/10] usb: musb: Fix PM runtime with delayed work

[Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>]

We have MUSB setting pm_runtime_irq_safe with the following
commits:

30a70b026b4c ("usb: musb: fix obex in g_nokia.ko causing kernel panic")
3e43a0725637 ("usb: musb: core: add pm_runtime_irq_safe()")

Let's fix things to use delayed work so we can remove the
pm_runtime_irq_safe.

Note that we may want to set this up in a generic way in the
gadget framework eventually.

Signed-off-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
---
 drivers/usb/musb/musb_core.h   |  1 +
 drivers/usb/musb/musb_gadget.c | 23 +++++++++++++++++------
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index b6afe9e..2947384 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -312,6 +312,7 @@ struct musb {
 	struct work_struct	irq_work;
 	struct delayed_work	deassert_reset_work;
 	struct delayed_work	finish_resume_work;
+	struct delayed_work	gadget_work;
 	u16			hwvers;
 
 	u16			intrrxe;
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index fff5a8a..2fc6557 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -1656,6 +1656,19 @@ static int musb_gadget_vbus_draw(struct usb_gadget *gadget, unsigned mA)
 	return usb_phy_set_power(musb->xceiv, mA);
 }
 
+static void musb_gadget_work(struct work_struct *work)
+{
+	struct musb *musb;
+	unsigned long flags;
+
+	musb = container_of(work, struct musb, gadget_work.work);
+	pm_runtime_get_sync(musb->controller);
+	spin_lock_irqsave(&musb->lock, flags);
+	musb_pullup(musb, musb->softconnect);
+	spin_unlock_irqrestore(&musb->lock, flags);
+	pm_runtime_put(musb->controller);
+}
+
 static int musb_gadget_pullup(struct usb_gadget *gadget, int is_on)
 {
 	struct musb	*musb = gadget_to_musb(gadget);
@@ -1663,20 +1676,16 @@ static int musb_gadget_pullup(struct usb_gadget *gadget, int is_on)
 
 	is_on = !!is_on;
 
-	pm_runtime_get_sync(musb->controller);
-
 	/* NOTE: this assumes we are sensing vbus; we'd rather
 	 * not pullup unless the B-session is active.
 	 */
 	spin_lock_irqsave(&musb->lock, flags);
 	if (is_on != musb->softconnect) {
 		musb->softconnect = is_on;
-		musb_pullup(musb, is_on);
+		schedule_delayed_work(&musb->gadget_work, 0);
 	}
 	spin_unlock_irqrestore(&musb->lock, flags);
 
-	pm_runtime_put(musb->controller);
-
 	return 0;
 }
 
@@ -1845,7 +1854,7 @@ int musb_gadget_setup(struct musb *musb)
 #elif IS_ENABLED(CONFIG_USB_MUSB_GADGET)
 	musb->g.is_otg = 0;
 #endif