linux-kernel - [PATCH v2 3/3] usb: musb: da8xx: Only execute the OTG workaround when phy in OTG mode

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Message-Id: <1477479503-5131-4-git-send-email-abailon@baylibre.com>
Date:   Wed, 26 Oct 2016 12:58:23 +0200
From:   Alexandre Bailon <abailon@...libre.com>
To:     khilman@...libre.com, david@...hnology.com, b-liu@...com,
        balbi@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        Alexandre Bailon <abailon@...libre.com>
Subject: [PATCH v2 3/3] usb: musb: da8xx: Only execute the OTG workaround when phy in OTG mode

When the phy is forced in host mode, only the first hot plug and
hot remove works. That is actually because the driver execute the
OTG workaround, whereas it is not applicable in host or device mode.
Indeed, to work correctly, the VBUS sense and session end comparator
must be enabled, what is only possible when the phy is in OTG mode.
Only execute the workaround if the phy is in OTG mode.

Signed-off-by: Alexandre Bailon <abailon@...libre.com>
---
 drivers/usb/musb/da8xx.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/usb/musb/da8xx.c b/drivers/usb/musb/da8xx.c
index 6749aa1..b8a6b65 100644
--- a/drivers/usb/musb/da8xx.c
+++ b/drivers/usb/musb/da8xx.c
@@ -145,6 +145,17 @@ static void otg_timer(unsigned long _musb)
 	unsigned long		flags;
 
 	/*
+	 * We should only execute the OTG workaround when the phy is in OTG
+	 * mode. The workaround require the VBUS sense and the session end
+	 * comparator to be enabled, what is only possible if the phy is in
+	 * OTG mode. As the workaround is only required to detect if the
+	 * controller must act as host or device, we can safely exit OTG is
+	 * not in use.
+	 */
+	if (musb->port_mode != MUSB_PORT_MODE_DUAL_ROLE)
+		return;
+
+	/*
 	 * We poll because DaVinci's won't expose several OTG-critical
 	 * status change events (from the transceiver) otherwise.
 	 */
-- 
2.7.3