usb: musb: Improve PM runtime and phy handling for 2430 glue layer

This simplifies things and allows idling both MUSB and PHY
when nothing is configured. Let's just return early from PM
runtime if musb is not yet initialized.

Let's also warn if PHY is not configured.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
index fa99329..b81216d 100644
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -435,6 +435,7 @@
 		return PTR_ERR(musb->phy);
 	}
 	musb->isr = omap2430_musb_interrupt;
+	phy_init(musb->phy);
 
 	/*
 	 * Enable runtime PM for musb parent (this driver). We can't
@@ -471,8 +472,6 @@
 	if (glue->status != MUSB_UNKNOWN)
 		omap_musb_set_mailbox(glue);
 
-	phy_init(musb->phy);
-	phy_power_on(musb->phy);
 	pm_runtime_put(glue->dev);
 	return 0;
 
@@ -489,6 +488,9 @@
 	struct musb_hdrc_platform_data *pdata = dev_get_platdata(dev);
 	struct omap_musb_board_data *data = pdata->board_data;
 
+	if (!WARN_ON(!musb->phy))
+		phy_power_on(musb->phy);
+
 	omap2430_set_power(musb, true, glue->cable_connected);
 
 	switch (glue->status) {
@@ -526,6 +528,9 @@
 	struct device *dev = musb->controller;
 	struct omap2430_glue *glue = dev_get_drvdata(dev->parent);
 
+	if (!WARN_ON(!musb->phy))
+		phy_power_off(musb->phy);
+
 	if (glue->status != MUSB_UNKNOWN)
 		omap_control_usb_set_mode(glue->control_otghs,
 			USB_MODE_DISCONNECT);
@@ -535,11 +540,14 @@
 
 static int omap2430_musb_exit(struct musb *musb)
 {
-	del_timer_sync(&musb_idle_timer);
+	struct device *dev = musb->controller;
+	struct omap2430_glue *glue = dev_get_drvdata(dev->parent);
 
+	del_timer_sync(&musb_idle_timer);
 	omap2430_low_level_exit(musb);
-	phy_power_off(musb->phy);
 	phy_exit(musb->phy);
+	musb->phy = NULL;
+	cancel_work_sync(&glue->omap_musb_mailbox_work);
 
 	return 0;
 }
@@ -707,7 +715,6 @@
 	struct musb *musb = glue_to_musb(glue);
 
 	pm_runtime_get_sync(glue->dev);
-	cancel_work_sync(&glue->omap_musb_mailbox_work);
 	platform_device_unregister(glue->musb);
 	omap2430_set_power(musb, false, false);
 	pm_runtime_put_sync(glue->dev);
@@ -723,12 +730,13 @@
 	struct omap2430_glue		*glue = dev_get_drvdata(dev);
 	struct musb			*musb = glue_to_musb(glue);
 
-	if (musb) {
-		musb->context.otg_interfsel = musb_readl(musb->mregs,
-				OTG_INTERFSEL);
+	if (!musb)
+		return 0;
 
-		omap2430_low_level_exit(musb);
-	}
+	musb->context.otg_interfsel = musb_readl(musb->mregs,
+						 OTG_INTERFSEL);
+
+	omap2430_low_level_exit(musb);
 
 	return 0;
 }
@@ -739,7 +747,7 @@
 	struct musb			*musb = glue_to_musb(glue);
 
 	if (!musb)
-		return -EPROBE_DEFER;
+		return 0;
 
 	omap2430_low_level_init(musb);
 	musb_writel(musb->mregs, OTG_INTERFSEL,