watchdog: da9063_wdt: don't trigger watchdog too fast

Triggering the watchdog faster than T_WDMIN=256ms leads to resets of the
DA9063 chip. The datasheet says that the watchdog must only be triggered
in the timeframe T_WDMIN to T_WDMAX. The T_WDMAX is configured in the
driver.

Signed-off-by: Stefan Christ <[e-mail]>
Reviewed-by: Guenter Roeck <[e-mail]>
Signed-off-by: Guenter Roeck <[e-mail]>
Signed-off-by: Wim Van Sebroeck <[e-mail]>

drivers/watchdog/da9063_wdt.c

···
 #define DA9063_WDT_MIN_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MIN]
 #define DA9063_WDT_MAX_TIMEOUT		wdt_timeout[DA9063_TWDSCALE_MAX]
 #define DA9063_WDG_TIMEOUT		wdt_timeout[3]
+#define DA9063_RESET_PROTECTION_MS	256
 
 struct da9063_watchdog {
 	struct da9063 *da9063;
···
 	wdt->wdtdev.ops = &da9063_watchdog_ops;
 	wdt->wdtdev.min_timeout = DA9063_WDT_MIN_TIMEOUT;
 	wdt->wdtdev.max_timeout = DA9063_WDT_MAX_TIMEOUT;
+	wdt->wdtdev.min_hw_heartbeat_ms = DA9063_RESET_PROTECTION_MS;
 	wdt->wdtdev.timeout = DA9063_WDG_TIMEOUT;
 	wdt->wdtdev.parent = &pdev->dev;