If the timeout value is set more than once the DA9063 watchdog triggers
a reset signal which reset the system.
The DA9063 watchdog timeout register field TWDSCALE combines two functions:
setting the timeout value scale and enabling the watchdog. If the
watchdog is enabled we have to disable the watchdog, wait some time due
to a HW issue and set the new timeout value. Setting the new timeout
value reenables the watchdog.
We have to buffer the timeout value because the DA9063 can't set a
timeout without enabling the watchdog (as described above). The buffered
value will then set by the next wdt_start() call.
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 | 54 ++++++++++++++++++++++++++++++-----
1 file changed, 47 insertions(+), 7 deletions(-)
diff --git a/drivers/watchdog/da9063_wdt.c b/drivers/watchdog/da9063_wdt.c
index b17ac1bb1f28..1e2ecb76dcb1 100644
--- a/drivers/watchdog/da9063_wdt.c
+++ b/drivers/watchdog/da9063_wdt.c
@@ -45,10 +45,51 @@ static unsigned int da9063_wdt_timeout_to_sel(unsigned int secs)
return DA9063_TWDSCALE_MAX;
}
-static int _da9063_wdt_set_timeout(struct da9063 *da9063, unsigned int regval)
+/*
+ * 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_stop(struct watchdog_device *wdd);
+static int
+_da9063_wdt_set_timeout(struct watchdog_device *wdd, unsigned int regval)
{
- return regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
- DA9063_TWDSCALE_MASK, regval);
+ struct da9063 *da9063 = watchdog_get_drvdata(wdd);
+ int ret = 0;
+
+ /*
+ * The watchdog triggers a reboot if a timeout value is already
+ * programmed because 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.
+ *
+ * We have to cache the timeout value since we can't update the value
+ * without enabling the watchdog. This case may happen if the watchdog
+ * is disabled and we only want to update the timeout value.
+ */
+
+ if (watchdog_hw_running(wdd)) {
+ /* Don't try to update the value if disabling fails */
+ ret = da9063_wdt_stop(wdd);
+ if (ret)
+ goto out;
+
+ usleep_range(150, 300);
+
+ ret = regmap_update_bits(da9063->regmap, DA9063_REG_CONTROL_D,
+ DA9063_TWDSCALE_MASK, regval);
+ }
+
+ wdd->timeout = regval;
+out:
+ return ret;
}
static int da9063_wdt_start(struct watchdog_device *wdd)
@@ -58,7 +99,7 @@ static int da9063_wdt_start(struct watchdog_device *wdd)
int ret;
selector = da9063_wdt_timeout_to_sel(wdd->timeout);
- ret = _da9063_wdt_set_timeout(da9063, selector);
+ ret = _da9063_wdt_set_timeout(wdd, selector);
if (ret)
dev_err(da9063->dev, "Watchdog failed to start (err = %d)\n",
ret);
@@ -85,8 +126,7 @@ 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);
@@ -102,7 +142,7 @@ static int da9063_wdt_set_timeout(struct watchdog_device *wdd,
int ret;
selector = da9063_wdt_timeout_to_sel(timeout);
- ret = _da9063_wdt_set_timeout(da9063, selector);
+ ret = _da9063_wdt_set_timeout(wdd, selector);
if (ret)
dev_err(da9063->dev, "Failed to set watchdog timeout (err = %d)\n",
ret);
--
2.17.0
--
To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
