We have to wait at least the minimium time for the watchdog window (TWDMIN) before writings to the wdt register after the watchdog is activated. Otherwise the chip will assert TWD_ERROR and power down to reset mode. Signed-off-by: Marcus Folkesson <marcus.folkesson@xxxxxxxxx> --- The current implementation does not respect the time window for all cases not it handle when the jiffie wrap around. E.g. setting a new timeout and immediately perform a 'ping' causes the chip to assert TWD_ERROR. --- Changes in v2: - Use the right author email. - Link to v1: https://lore.kernel.org/r/20250129-da9052-v1-1-aa0dfc2ad595@xxxxxxxxx --- drivers/watchdog/da9052_wdt.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) diff --git a/drivers/watchdog/da9052_wdt.c b/drivers/watchdog/da9052_wdt.c index 77039f2f0be54273df1666fe40c413b6c89285a1..5ca957a6c2219d99cb3e653205e3f556f7cfb56f 100644 --- a/drivers/watchdog/da9052_wdt.c +++ b/drivers/watchdog/da9052_wdt.c @@ -45,6 +45,21 @@ static const struct { { 7, 131 }, }; +static void da9052_wdt_wait_for_twdmin(struct watchdog_device *wdt_dev) +{ + struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); + unsigned long msecs, twdmin, jnow = jiffies; + + /* + * The host must wait at least TWDMIN ms between writings to the watchdog + * register or the DA9052 will assert TWD_ERROR and power down to RESET mode. + */ + twdmin = driver_data->jpast + msecs_to_jiffies(DA9052_TWDMIN); + if (time_before(jnow, twdmin)) { + msecs = jiffies_to_msecs(twdmin - jnow); + mdelay(msecs); + } +} static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev, unsigned int timeout) @@ -53,6 +68,7 @@ static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev, struct da9052 *da9052 = driver_data->da9052; int ret, i; + da9052_wdt_wait_for_twdmin(wdt_dev); /* * Disable the Watchdog timer before setting * new time out. @@ -89,8 +105,8 @@ static int da9052_wdt_set_timeout(struct watchdog_device *wdt_dev, } wdt_dev->timeout = timeout; - driver_data->jpast = jiffies; } + driver_data->jpast = jiffies; return 0; } @@ -109,16 +125,9 @@ static int da9052_wdt_ping(struct watchdog_device *wdt_dev) { struct da9052_wdt_data *driver_data = watchdog_get_drvdata(wdt_dev); struct da9052 *da9052 = driver_data->da9052; - unsigned long msec, jnow = jiffies; int ret; - /* - * We have a minimum time for watchdog window called TWDMIN. A write - * to the watchdog before this elapsed time should cause an error. - */ - msec = (jnow - driver_data->jpast) * 1000/HZ; - if (msec < DA9052_TWDMIN) - mdelay(msec); + da9052_wdt_wait_for_twdmin(wdt_dev); /* Reset the watchdog timer */ ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, @@ -130,8 +139,11 @@ static int da9052_wdt_ping(struct watchdog_device *wdt_dev) * FIXME: Reset the watchdog core, in general PMIC * is supposed to do this */ - return da9052_reg_update(da9052, DA9052_CONTROL_D_REG, + ret = da9052_reg_update(da9052, DA9052_CONTROL_D_REG, DA9052_CONTROLD_WATCHDOG, 0 << 7); + + driver_data->jpast = jiffies; + return ret; } static const struct watchdog_info da9052_wdt_info = { @@ -187,6 +199,7 @@ static int da9052_wdt_probe(struct platform_device *pdev) return ret; } + driver_data->jpast = jiffies; return devm_watchdog_register_device(dev, &driver_data->wdt); } --- base-commit: 05dbaf8dd8bf537d4b4eb3115ab42a5fb40ff1f5 change-id: 20250129-da9052-661dfbb7de38 Best regards, -- Marcus Folkesson <marcus.folkesson@xxxxxxxxx>
