usb: musb: Return error value from musb_mailbox

At least on n900 we have phy-twl4030-usb only generating cable
interrupts, and then have a separate USB PHY.

In order for musb to know the real cable status, we need to
clear any cached state until musb is ready. Otherwise the cable
status interrupts will get just ignored if the status does
not change from the initial state.

To do this, let's add a return value to musb_mailbox(), and
reset cached linkstat to MUSB_UNKNOWN on error. Sorry to cause
a bit of churn here, I should have added that already last time
patching musb_mailbox().

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>

4 files changed, 19 insertions, 10 deletions

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 23888d5..6469eff 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -1679,7 +1679,7 @@ EXPORT_SYMBOL_GPL(musb_dma_completion);
 #define use_dma			0
 #endif
 
-static void (*musb_phy_callback)(enum musb_vbus_id_status status);
+static int (*musb_phy_callback)(enum musb_vbus_id_status status);
 
 /*
  * musb_mailbox - optional phy notifier function
@@ -1688,11 +1688,12 @@ static void (*musb_phy_callback)(enum musb_vbus_id_status status);
  * Optionally gets called from the USB PHY. Note that the USB PHY must be
  * disabled at the point the phy_callback is registered or unregistered.
  */
-void musb_mailbox(enum musb_vbus_id_status status)
+int musb_mailbox(enum musb_vbus_id_status status)
 {
 	if (musb_phy_callback)
-		musb_phy_callback(status);
+		return musb_phy_callback(status);
 
+	return -ENODEV;
 };
 EXPORT_SYMBOL_GPL(musb_mailbox);
 
diff --git a/drivers/usb/musb/musb_core.h b/drivers/usb/musb/musb_core.h
index 2947384..b55a776 100644
--- a/drivers/usb/musb/musb_core.h
+++ b/drivers/usb/musb/musb_core.h
@@ -215,7 +215,7 @@ struct musb_platform_ops {
 				dma_addr_t *dma_addr, u32 *len);
 	void	(*pre_root_reset_end)(struct musb *musb);
 	void	(*post_root_reset_end)(struct musb *musb);
-	void	(*phy_callback)(enum musb_vbus_id_status status);
+	int	(*phy_callback)(enum musb_vbus_id_status status);
 };
 
 /*
diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
index d312d42..2c54f52 100644
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -180,22 +180,24 @@ static void omap2430_set_power(struct musb *musb, bool enabled, bool cable)
 	}
 }
 
-static void omap2430_musb_mailbox(enum musb_vbus_id_status status)
+static int omap2430_musb_mailbox(enum musb_vbus_id_status status)
 {
 	struct omap2430_glue	*glue = _glue;
 
 	if (!glue) {
 		pr_err("%s: musb core is not yet initialized\n", __func__);
-		return;
+		return -EPROBE_DEFER;
 	}
 	glue->status = status;
 
 	if (!glue_to_musb(glue)) {
 		pr_err("%s: musb core is not yet ready\n", __func__);
-		return;
+		return -EPROBE_DEFER;
 	}
 
 	schedule_work(&glue->omap_musb_mailbox_work);
+
+	return 0;
 }
 
 static void omap_musb_set_mailbox(struct omap2430_glue *glue)
diff --git a/drivers/usb/phy/phy-twl6030-usb.c b/drivers/usb/phy/phy-twl6030-usb.c
index 24e2b3c..c66a447 100644
--- a/drivers/usb/phy/phy-twl6030-usb.c
+++ b/drivers/usb/phy/phy-twl6030-usb.c
@@ -227,12 +227,16 @@ static irqreturn_t twl6030_usb_irq(int irq, void *_twl)
 			twl->asleep = 1;
 			status = MUSB_VBUS_VALID;
 			twl->linkstat = status;
-			musb_mailbox(status);
+			ret = musb_mailbox(status);
+			if (ret)
+				twl->linkstat = MUSB_UNKNOWN;
 		} else {
 			if (twl->linkstat != MUSB_UNKNOWN) {
 				status = MUSB_VBUS_OFF;
 				twl->linkstat = status;
-				musb_mailbox(status);
+				ret = musb_mailbox(status);
+				if (ret)
+					twl->linkstat = MUSB_UNKNOWN;
 				if (twl->asleep) {
 					regulator_disable(twl->usb3v3);
 					twl->asleep = 0;
@@ -264,7 +268,9 @@ static irqreturn_t twl6030_usbotg_irq(int irq, void *_twl)
 		twl6030_writeb(twl, TWL_MODULE_USB, 0x10, USB_ID_INT_EN_HI_SET);
 		status = MUSB_ID_GROUND;
 		twl->linkstat = status;
-		musb_mailbox(status);
+		ret = musb_mailbox(status);
+		if (ret)
+			twl->linkstat = MUSB_UNKNOWN;
 	} else  {
 		twl6030_writeb(twl, TWL_MODULE_USB, 0x10, USB_ID_INT_EN_HI_CLR);
 		twl6030_writeb(twl, TWL_MODULE_USB, 0x1, USB_ID_INT_EN_HI_SET);