From 13b600b59df287a175b1476d2d588ab935092b58 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Albrecht=20Dre=C3=9F?= Date: Fri, 13 Nov 2009 11:09:30 -0700 Subject: [PATCH] mpc52xx/wdt: OF property to enable the WDT on boot MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Grant Likely --- .../powerpc/dts-bindings/fsl/mpc5200.txt | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) 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 = ; +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: -- 2.30.2