diff options
| author | Wolfram Sang <wsa+renesas@sang-engineering.com> | 2018-11-07 20:46:02 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-02-12 19:46:03 +0100 |
| commit | 18ddd41b3ea1a064425fdf2bbdfc5b3cd6e4a185 (patch) | |
| tree | 691f5b046bf898c74fbf7f8c49da24d35a7d2e2d /drivers/watchdog | |
| parent | 03a127ef9b58df879594dbac1dd6cc5b38acaab9 (diff) | |
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: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/watchdog')
| -rw-r--r-- | drivers/watchdog/renesas_wdt.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c index 831ef83f6de1..c4a17d72d025 100644 --- a/drivers/watchdog/renesas_wdt.c +++ b/drivers/watchdog/renesas_wdt.c @@ -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(); |