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* [PATCH AUTOSEL 4.9 11/13] watchdog: da9062: do not ping the hw during stop()
       [not found] <20200303025002.10600-1-sashal@kernel.org>
@ 2020-03-03  2:50 ` Sasha Levin
  0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2020-03-03  2:50 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Marco Felsch, Guenter Roeck, Wim Van Sebroeck, Sasha Levin,
	linux-watchdog

From: Marco Felsch <m.felsch@pengutronix.de>

[ Upstream commit e9a0e65eda3f78d0b04ec6136c591c000cbc3b76 ]

The da9062 hw has a minimum ping cool down phase of at least 200ms. The
driver takes that into account by setting the min_hw_heartbeat_ms to
300ms and the core guarantees that the hw limit is observed for the
ping() calls. But the core can't guarantee the required minimum ping
cool down phase if a stop() command is send immediately after the ping()
command. So it is not allowed to ping the watchdog within the stop()
command as the driver does. Remove the ping can be done without doubts
because the watchdog gets disabled anyway and a (re)start resets the
watchdog counter too.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200120091729.16256-1-m.felsch@pengutronix.de
[groeck: Updated description]
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/da9062_wdt.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
index 7386111220d58..daeb645fcea8a 100644
--- a/drivers/watchdog/da9062_wdt.c
+++ b/drivers/watchdog/da9062_wdt.c
@@ -126,13 +126,6 @@ static int da9062_wdt_stop(struct watchdog_device *wdd)
 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 	int ret;
 
-	ret = da9062_reset_watchdog_timer(wdt);
-	if (ret) {
-		dev_err(wdt->hw->dev, "Failed to ping the watchdog (err = %d)\n",
-			ret);
-		return ret;
-	}
-
 	ret = regmap_update_bits(wdt->hw->regmap,
 				 DA9062AA_CONTROL_D,
 				 DA9062AA_TWDSCALE_MASK,
-- 
2.20.1


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2020-03-03  2:50 ` [PATCH AUTOSEL 4.9 11/13] watchdog: da9062: do not ping the hw during stop() Sasha Levin

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