[PATCH 4/4] watchdog: sama5d4: Add comment explaining what happens on resume

Alexandre Belloni alexandre.belloni at free-electrons.com
Thu Mar 2 09:31:14 PST 2017

Because suspending to RAM may lose the register values, they are restored
on resume. This is currently done unconditionally because there is
currently no way to know (from the driver) whether they have really been
lost or are still valid. Writing MR also pings the watchdog and this may
not be what is expected so add a comment explaining why it happens.

Signed-off-by: Alexandre Belloni <alexandre.belloni at free-electrons.com>
 drivers/watchdog/sama5d4_wdt.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
index d710014f3b7d..0ae947c3d7bc 100644
--- a/drivers/watchdog/sama5d4_wdt.c
+++ b/drivers/watchdog/sama5d4_wdt.c
@@ -300,6 +300,11 @@ static int sama5d4_wdt_resume(struct device *dev)
 	struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
+	/*
+	 * FIXME: writing MR also pings the watchdog which may not be desired.
+	 * This should only be done when the registers are lost on suspend but
+	 * there is no way to get this information right now.
+	 */
 	return 0;

More information about the linux-arm-kernel mailing list