-#define wdt_write(wtd, field, val) \
- writel_relaxed((val), (wdt)->reg_base + (field))
+/* 4 slow clock periods is 4/32768 = 122.07µs*/
+#define WDT_DELAY usecs_to_jiffies(123)
+
+static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val)
+{
+ /*
+ * WDT_CR and WDT_MR must not be modified within three slow clock
+ * periods following a restart of the watchdog performed by a write
+ * access in WDT_CR.
+ */
+ while (time_before(jiffies, wdt->last_ping + WDT_DELAY))
+ usleep_range(30, 125);
+ writel_relaxed(val, wdt->reg_base + field);
+ wdt->last_ping = jiffies;
+}
+
+static void wdt_write_nosleep(struct sama5d4_wdt *wdt, u32 field, u32 val)
+{
+ if (time_before(jiffies, wdt->last_ping + WDT_DELAY))
+ udelay(123);
+ writel_relaxed(val, wdt->reg_base + field);
+ wdt->last_ping = jiffies;
+}