If the timeout value is set more than once the DA9063 watchdog triggers
a reset signal which reset the system.
To update the timeout value we have to disable the watchdog, clear the
watchdog counter value and write the new timeout value to the watchdog.
Clearing the counter value is a feature to be on the safe side because the
data sheet doesn't describe the behaviour of the watchdog counter value
after a watchdog disabling-enable-sequence.
The patch is based on Philipp Zabel's previous patch.
Fixes: 5e9c16e37608 ("watchdog: Add DA9063 PMIC watchdog driver.")
Signed-off-by: Marco Felsch <m.felsch@xxxxxxxxxxxxxx>
---
drivers/watchdog/da9063_wdt.c | 35 +++++++++++++++++++++++++++++++++--
1 file changed, 33 insertions(+), 2 deletions(-)
diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
index b17ac1bb1f28..06fcc662673e 100644
--- a/drivers/watchdog/da9063_wdt.c
+++ b/drivers/watchdog/da9063_wdt.c
@@ -45,8 +45,40 @@ static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
return DA9063_TWDSCALE_MAX;
}
+/*
+ * Writing a '1' to the self-clearing WATCHDOG bit resets the watchdog counter
+ * value.
+ */
+static int _da9063_wdt_reset_timer(struct da9063 *da9063)
+{
+ return regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
+ DA9063_WATCHDOG);
+}
+
static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
{
+ int ret;
+
+ /*
+ * The watchdog triggers a reboot if a timeout value is already
+ * programmed. The reason for this is that the timeout value
+ * combines two functions in one: indicating the counter limit and
+ * starting the watchdog. The watchdog must be disabled to be able to
+ * change the timeout value if the watchdog is already running. Then
+ * we can set the new timeout value which enables the watchdog again.
+ */
+ ret = regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
+ DA9063_TWDSCALE_MASK, DA9063_TWDSCALE_DISABLE);
+ if (ret)
+ dev_warn(da9063->dev,
+ "Failed to disable watchdog before setting new timeout\n");
+
+ usleep_range(150, 300);
+
+ ret = _da9063_wdt_reset_timer(da9063);
+ if (ret)
+ dev_warn(da9063->dev, "Failed to reset watchdog counter\n");
+
return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
DA9063_TWDSCALE_MASK, regval);
}
@@ -85,8 +117,7 @@ static int da9063_wdt_ping(struct watchdog_device *wdd)
struct da9063 *da9063 = watchdog_get_drvdata(wdd);
int ret;
- ret = regmap_write(da9063->regmap, DA9063_REG_CONTROL_F,
- DA9063_WATCHDOG);
+ ret = _da9063_wdt_reset_timer(da9063);
if (ret)
dev_alert(da9063->dev, "Failed to ping the watchdog (err = %d)\n",
ret);
--
2.17.0
--
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