[PATCH] usb: musb: fix enumeration after resume

From: Andreas Kemnade <andreas@kemnade.info>
To: b-liu@ti.com, gregkh@linuxfoundation.org,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Tony Lindgren <tony@atomide.com>,
	Discussions about the Letux Kernel <letux-kernel@openphoenux.org>
Cc: Andreas Kemnade <andreas@kemnade.info>
Subject: [PATCH] usb: musb: fix enumeration after resume
Date: Sat, 27 Jan 2018 09:34:03 +0100	[thread overview]
Message-ID: <20180127083403.928-1-andreas@kemnade.info> (raw)

On dm3730 there are enumeration problems after resume.
Investigation led to the cause that the MUSB_POWER_SOFTCONN
bit is not set. If it was set before suspend (because it
was enabled via musb_pullup()), it is set in
musb_restore_context() so the pullup is enabled. But then
musb_start() is called which overwrites MUSB_POWER and
therefore disables MUSB_POWER_SOFTCONN, so no pullup is
enabled and the device is not enumerated.

So let's do a subset of what musb_start() does
in the same way as musb_suspend() does it. Platform-specific
stuff it still called as there might be some phy-related stuff
which needs to be enabled.
Also interrupts are enabled, as it was the original idea
of calling musb_start() in musb_resume() according to
Commit 6fc6f4b87cb3 ("usb: musb: Disable interrupts on suspend,
enable them on resume")

Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
---
 drivers/usb/musb/musb_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index ea5013aa69e2..255424aae513 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -2709,7 +2709,8 @@ static int musb_resume(struct device *dev)
 	if ((devctl & mask) != (musb->context.devctl & mask))
 		musb->port1_status = 0;
 
-	musb_start(musb);
+	musb_enable_interrupts(musb);
+	musb_platform_enable(musb);
 
 	spin_lock_irqsave(&musb->lock, flags);
 	error = musb_run_resume_work(musb);
-- 
2.11.0
