From: Wolfram Sang Date: Wed, 7 Nov 2018 19:46:02 +0000 (+0100) Subject: watchdog: renesas_wdt: don't set divider while watchdog is running X-Git-Tag: rel_imx_5.10.35_2.0.0-somdevices.0~5608^2~19 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=e990e12741877e9bfac402ca468f4007a75f6e2a;p=linux.git watchdog: renesas_wdt: don't set divider while watchdog is running 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 Reviewed-by: Fabrizio Castro Reviewed-by: Guenter Roeck Signed-off-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck --- diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c index b570962e84f3..c450e23e24a8 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();