@@ -103,7 +103,20 @@ fsl,mpc5200-gpt nodes
On the mpc5200 and 5200b, GPT0 has a watchdog timer function. If the board
design supports the internal wdt, then the device node for GPT0 should
-include the empty property 'fsl,has-wdt'.
+include the empty property 'fsl,has-wdt'. Note that this does not activate
+the watchdog. The timer will function as a GPT if the timer api is used, and
+it will function as watchdog if the watchdog device is used. The watchdog
+mode has priority over the gpt mode, i.e. if the watchdog is activated, any
+gpt api call to this timer will fail with -EBUSY.
+If you add the property
+ wdt,on-boot = <n>;
+GPT0 will be marked as in-use watchdog, i.e. blocking every gpt access to it.
+If n>0, the watchdog is started with a timeout of n seconds. If n=0, the
+configuration of the watchdog is not touched. This is useful in two cases:
+- just mark GPT0 as watchdog, blocking gpt accesses, and configure it later;
+- do not touch a configuration assigned by the boot loader which supervises
+ the boot process itself.
An mpc5200-gpt can be used as a single line GPIO controller. To do so,
add the following properties to the gpt node: