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List:       linux-usb
Subject:    [PATCH 1/4] usb: musb: omap2430: Wait on enable to avoid babble
From:       Tony Lindgren <tony () atomide ! com>
Date:       2019-08-30 23:20:55
Message-ID: 20190830232058.53414-2-tony () atomide ! com
[Download RAW message or body]

We can babble interrupt if we attempt to switch to USB host mode too
soon after enabling musb. Let's fix the issue by waiting a bit in
runtime_resume.

Cc: Jacopo Mondi <jacopo@jmondi.org>
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Michael Scott <hashcode0f@gmail.com>
Cc: NeKit <nekit1000@gmail.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/usb/musb/omap2430.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/musb/omap2430.c b/drivers/usb/musb/omap2430.c
--- a/drivers/usb/musb/omap2430.c
+++ b/drivers/usb/musb/omap2430.c
@@ -552,6 +552,9 @@ static int omap2430_runtime_resume(struct device *dev)
 	musb_writel(musb->mregs, OTG_INTERFSEL,
 		    musb->context.otg_interfsel);
 
+	/* Wait for musb to get oriented. Otherwise we can get babble */
+	usleep_range(200000, 250000);
+
 	return 0;
 }
 
-- 
2.23.0
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