lkml.org 
[lkml]   [2019]   [Feb]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.19 117/313] watchdog: renesas_wdt: dont set divider while watchdog is running
Date
4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

[ 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>
---
drivers/watchdog/renesas_wdt.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c
index 88d81feba4e6..d01efd342dc0 100644
--- a/drivers/watchdog/renesas_wdt.c
+++ b/drivers/watchdog/renesas_wdt.c
@@ -77,12 +77,17 @@ 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();
--
2.19.1


\
 
 \ /
  Last update: 2019-02-11 16:45    [W:0.666 / U:0.772 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site