i.MX28 Watchdog driver

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i.MX28 Watchdog driver

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Contributor III

Hi Everyone,

I'm working for some time now with running Linux on the mx28evk and I wanted to add watchdog functionality. But how do I do this? In the Linux kernel (3.7.8) I did find a "imx2_wdt.c" in drivers/watchdog, but this does not match the MX28 registers if I look at the reference manual. Also in the "platform-imx2-wdt.c" there are a number of CONFIG_SOC_IMX types listed, but not for the IMX28. It seems to be, that the watchdog implementation for the i.mx28 is quite different from the other i.mx types and therefore this peripheral is not supported (yet).

Can anyone tell me if there is watchdog support for the i.mx28, either in the mainline or in the maintained 2.6.35 kernel? In both versions I have not been able to find this....

Thanks,

Ruud

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NXP Employee
NXP Employee

Here is what you need to select in order to turn on the watchdog on mxs:

ARM: mxs_defconfig: Select watchdog driver - Patchwork

This patch has not reached mainline yet, but you can apply it on top of Linus' tree.

The watchdog driver for mxs is already in Linus' tree:

drivers/watchdog/stmp3xxx_rtc_wdt.c


Regards,


Fabio Estevam

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Contributor III

Hi Fabio,

Thanks for your reply. Meanwhile I did find an "mxs-wdt.c" in the 2.6.35 kernel from the ltib this afternoon. Except for some renaming of functions and changes between kernel revisions in some declarations, it is very similar to the "stmp3xxx_rtc_wdt.c" that you refer to. May I conclude that the WDT peripheral of the i.mx28 is copied from this stmp3xx family?

I will try and test things tomorrow and will post the results.

Regards,

Ruud

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Senior Contributor IV

Ruud

Had your issue got resolved? If yes, we are going to close the discussion in 3 days. If you still need help please feel

free to contact Freescale.

Thanks,
Yixing

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Contributor III

Sorry for the delay, but I ran into some other problems that kept me from testing this part. Anyway: I have been able to build the watchdog as a module and I can load and unload it with modprobe. What I can't find, is how this should be used any further. I came across some information about creating a /dev/watchdog device and references to /sys/class/watchdog, but I have not been able to figure out how to use this exactly. Some methods seem to describe a built-in software watchdog, but I doubt that it will use the imx peripheral then, as I intend to. I did some attempts, but for instance never get the probe message from the driver.

Can anyone help me in the right direction on how to use this watchdog peripheral?

Regards,

Ruud

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Senior Contributor IV

Ruud

This discussion is closed since no activity. If you still need help, please feel free to reply with an update to this

discussion, or create another discussion.
Thanks,
Yixing

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Senior Contributor II

FabioEstevam,  can you help here? :-)

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