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Commit 18ddd41b authored by Wolfram Sang's avatar Wolfram Sang Committed by Greg Kroah-Hartman
Browse files

watchdog: renesas_wdt: don't set divider while watchdog is running 



[ Upstream commit e990e12741877e9bfac402ca468f4007a75f6e2a ]

The datasheet says we must stop the timer before changing the clock
divider. This can happen when the restart handler is called while the
watchdog is running.

Signed-off-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: default avatarFabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 03a127ef

drivers/watchdog/renesas_wdt.c

+7 −2
Original line number Diff line number Diff line
@@ -74,12 +74,17 @@ static int rwdt_init_timeout(struct watchdog_device *wdev) 
static int rwdt_start(struct watchdog_device *wdev)

{

	struct rwdt_priv *priv = watchdog_get_drvdata(wdev);

	u8 val;



	pm_runtime_get_sync(wdev->parent);



	rwdt_write(priv, 0, RWTCSRB);

	rwdt_write(priv, priv->cks, RWTCSRA);

	/* Stop the timer before we modify any register */

	val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME;

	rwdt_write(priv, val, RWTCSRA);



	rwdt_init_timeout(wdev);

	rwdt_write(priv, priv->cks, RWTCSRA);

	rwdt_write(priv, 0, RWTCSRB);



	while (readb_relaxed(priv->base + RWTCSRA) & RWTCSRA_WRFLG)

		cpu_relax();