Trigger a watchdog pretimeout interrupt

[ababatola]

Hi,

I would like to trigger an interrupt when the pretimeout time of the watchdog is reached.  I have not seen a sutiable example.  I would like to ask if there is any available.  I am working with our imx8mp custom board. 

I have read alot on the topic and would like to clarify some issues

1.  Where would the pretimeout interrupt be enabled?  

2. Can it be read using a poll()?

3. Does all the interrupt of a particular watchdog timer uses the same interrupt number?

4.  How does the "watchdog_notify_pretimeout(wdog); " function in the imx2_wst.c works?

5. What other means are available for me to access the interrupt from user space?

Thanks

[AldoG]

Hello,

As specified in the i.MX8MP reference manual, the duration between interrupt event and timeout event can be controlled by writing to the WICT field of Watchdog Interrupt Control Register (WICR). It can vary between 0 and 127.5 seconds.

Yes, it can be polled, once the interrupt is triggered the WTIS bit in Watchdog Interrupt Control Register (WICR) will be set.

Watchdog_notify_pretimeout function is declared in linux/watchdog.h
https://github.com/nxp-imx/linux-imx/blob/66e442bc7fdcc935e6faa94c743f653263d4ed67/include/linux/wat...

For detailed descriptions about these IOCTLs, you may refer to the watchdog documentation:
https://github.com/nxp-imx/linux-imx/tree/lf-6.1.y/Documentation/watchdog

Best regards,
Aldo.