linux-kernel - [PATCH] usb: gadget: tegra-xudc: Fix idle suspend/resume

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Message-Id: <20200417170537.2540914-1-thierry.reding@gmail.com>
Date:   Fri, 17 Apr 2020 19:05:37 +0200
From:   Thierry Reding <thierry.reding@...il.com>
To:     Felipe Balbi <balbi@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Jon Hunter <jonathanh@...dia.com>,
        Nagarjuna Kristam <nkristam@...dia.com>,
        linux-usb@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] usb: gadget: tegra-xudc: Fix idle suspend/resume

From: Thierry Reding <treding@...dia.com>

When the XUDC device is idle (i.e. powergated), care must be taken not
to access any registers because that would lead to a crash.

Move the call to tegra_xudc_device_mode_off() into the same conditional
as the tegra_xudc_powergate() call to make sure we only force device
mode off if the XUDC is actually powered up.

Fixes: 49db427232fe ("usb: gadget: Add UDC driver for tegra XUSB device mode controller")
Signed-off-by: Thierry Reding <treding@...dia.com>
---
 drivers/usb/gadget/udc/tegra-xudc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/udc/tegra-xudc.c b/drivers/usb/gadget/udc/tegra-xudc.c
index 52a6add961f4..dfabc54cdc27 100644
--- a/drivers/usb/gadget/udc/tegra-xudc.c
+++ b/drivers/usb/gadget/udc/tegra-xudc.c
@@ -3840,11 +3840,11 @@ static int __maybe_unused tegra_xudc_suspend(struct device *dev)
 
 	flush_work(&xudc->usb_role_sw_work);
 
-	/* Forcibly disconnect before powergating. */
-	tegra_xudc_device_mode_off(xudc);
-
-	if (!pm_runtime_status_suspended(dev))
+	if (!pm_runtime_status_suspended(dev)) {
+		/* Forcibly disconnect before powergating. */
+		tegra_xudc_device_mode_off(xudc);
 		tegra_xudc_powergate(xudc);
+	}
 
 	pm_runtime_disable(dev);
 
-- 
2.24.1