Re: [PATCH 10/15] usb: musb: Don't set d+ high before enable for 2430 glue layer

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

* Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> [160513 14:19]:
> * Bin Liu <b-liu-l0cyMroinI0@public.gmane.org> [160513 14:05]:
> > In stead of removing it, session bit should only be set when musb_mode
> > == MUSB_HOST, will this fix the D+ pullup problem?
> 
> Good point, I forgot about it being specific to host mode. I'll check.

Yeah good call, the patch below fixes the issue. Then we can remove the
set_mode later if the generic approach looks OK to you.

Regards,

Tony

8< ----------------------
From: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>
Date: Fri, 13 May 2016 07:59:35 -0700
Subject: [PATCH] usb: musb: Don't set d+ high before enable for 2430 glue
 layer

At least 2430 glue layer pulls d+ high on start up even if there are
no gadgets configured. This is bad at least for anything using a separate
battery charger chip as it can confuse the charger detection.

Let's fix the issue by only setting the SESSION bit in host mode
as suggested by Bin Liu <b-liu-l0cyMroinI0@public.gmane.org>.

Signed-off-by: Tony Lindgren <tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org>

--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -124,8 +124,12 @@ static void omap2430_musb_set_vbus(struct musb *musb, int is_on)
 
 static int omap2430_musb_set_mode(struct musb *musb, u8 musb_mode)
 {
-	u8	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
+	u8 devctl;
 
+	if (musb_mode != MUSB_HOST)
+		return 0;
+
+	devctl = musb_readb(musb->mregs, MUSB_DEVCTL);
 	devctl |= MUSB_DEVCTL_SESSION;
 	musb_writeb(musb->mregs, MUSB_DEVCTL, devctl);
 
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