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| author | Albrecht Dreß <albrecht.dress@arcor.de> | 2009-11-13 19:09:30 +0100 |
|---|---|---|
| committer | Grant Likely <grant.likely@secretlab.ca> | 2009-11-13 19:09:30 +0100 |
| commit | 13b600b59df287a175b1476d2d588ab935092b58 (patch) | |
| tree | bca214b840b7260e27b3be1df45e7af4a8e9ba38 /Documentation | |
| parent | mpc5200/gpt: tiny fix for gpt period limitation (diff) | |
| download | linux-13b600b59df287a175b1476d2d588ab935092b58.tar.xz linux-13b600b59df287a175b1476d2d588ab935092b58.zip | |
mpc52xx/wdt: OF property to enable the WDT on boot
Add the "fsl,wdt-on-boot" OF property as to reserve a GPT as WDT which may
be a requirement in safety-related (e.g. ISO/EN 61508) applications.
Signed-off-by: Albrecht Dreß <albrecht.dress@arcor.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/powerpc/dts-bindings/fsl/mpc5200.txt | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt index 8447fd7090d0..ddd5ee32ea63 100644 --- a/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt +++ b/Documentation/powerpc/dts-bindings/fsl/mpc5200.txt @@ -103,7 +103,22 @@ 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 + fsl,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. + +The watchdog will respect the CONFIG_WATCHDOG_NOWAYOUT option. An mpc5200-gpt can be used as a single line GPIO controller. To do so, add the following properties to the gpt node: |