linux-kernel - [PATCH 4.19 23/86] watchdog: da9062: do not ping the hw during stop()

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Message-Id: <20200310124532.033672877@linuxfoundation.org>
Date:   Tue, 10 Mar 2020 13:44:47 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Marco Felsch <m.felsch@...gutronix.de>,
        Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 4.19 23/86] watchdog: da9062: do not ping the hw during stop()

From: Marco Felsch <m.felsch@...gutronix.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@...gutronix.de>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
Link: https://lore.kernel.org/r/20200120091729.16256-1-m.felsch@pengutronix.de
[groeck: Updated description]
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@...ux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@...nel.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 fe169d8e1fb2f..7f0a8e6352860 100644
--- a/drivers/watchdog/da9062_wdt.c
+++ b/drivers/watchdog/da9062_wdt.c
@@ -99,13 +99,6 @@ 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