Messages in this thread | | | Date | Wed, 22 Jul 2009 17:09:11 +0200 | From | Simon Braunschmidt <> | Subject | Handling multiple watchdogs |
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Hi
I have two watchdogs on my board that I both want to handle. What would be the proper approach in this case?
What I can see currently is that most (all?) watchdogs register as chardev 10:130, that breaks when registering more than one.
I work around this in my private tree by something like:
-------8<-----------------
#ifndef WATCHDOG_MINOR #define WATCHDOG_MINOR 130 #endif #define WATCHDOG0_MINOR 212 #define WATCHDOG_NUMDEVS 2
static struct watchdog_dev_id watchdog_possible_devs[] = { [0] = { .minor = WATCHDOG_MINOR, .name = "watchdog", }, [1] = { .minor = WATCHDOG0_MINOR, .name = "watchdog0", }, };
/* watchdogs can also use unusual minor numbers, try them when we fail*/ for (i = 0; i < WATCHDOG_NUMDEVS; i++) { wdt_miscdev.minor=watchdog_possible_devs[i].minor; wdt_miscdev.name=watchdog_possible_devs[i].name; ret = misc_register(&wdt_miscdev); if (ret == 0) break; printk(KERN_INFO PFX "failed to register miscdev on minor=%d (err=%d)\n", wdt_miscdev.minor, ret); } if (ret != 0) { goto unreg_reboot; }
----------------->8---------
Which gives me an additional watchdog chardevice on 10:212.
This approach is probably not the best, so i am not asking for inclusion of such a change. One solution would be to expose the watchdogs individually like /dev/watchdog0, /dev/watchdog1 and so on and to expose a combined interface under /dev/watchdog.
I have searched the list and found some related discussion like http://article.gmane.org/gmane.linux.kernel/398831/match=watchdogs other threads and http://git.kernel.org/?p=linux/kernel/git/wim/linux-2.6-watchdog-experimental.git;a=summary
, yet it does not seem like this reached mainline so far.
Any sharing of thoughts on the subject would be welcome.
Best Regards Simon Braunschmidt
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