Hello Guenter, On Thu, Jul 30, 2015 at 12:25:07AM -0700, Guenter Roeck wrote: > On 07/29/2015 11:59 PM, Uwe Kleine-König wrote: > >On Wed, Jul 29, 2015 at 08:49:23AM -0700, Guenter Roeck wrote: > >>On 07/29/2015 12:35 AM, Uwe Kleine-König wrote: > >>>>always-running is meant to indicate that the watchdog can not be stopped > >>>>(meaning a timer has to be used to send keepalives while the watchdog > >>>>device is closed). The documentation specifically states that. > >>>> > >>>> "If the watchdog timer cannot be disabled ..." > >>>> > >>>>How would you express that condition without always-running or a similar > >>>>attribute ? I am also not sure how that relates to hw_algo; I thought > >>>>those properties are orthogonal. > >>>For hw_algo = "level" the inactive level of the gpio disables the > >>>watchdog (and resets the counter). So always-running doesn't make sense > >>>for this type. > >>> > >>That is not what is currently implemented. "level" just means that > >I'm not talking (yet) about the implementation. > >>the watchdog is pinged using a -high-low-high- or -low-high-low- > >>sequence, while toggle means that the level is changed with each > >>ping (-low-(wait)-high-(wait)-low-(wait)-high-...). > >Currently the document tells us: > > > > hw_algo: [...] > > - level: Low or high level starts counting WDT timeout, the > > opposite level disables the WDT. > > > >So similar to the "toggle" description there is some behaviour about > >being disabled in certain states implied. > > > > It might be that you put too much emphasis on the documentation and > little or none on the code. We already established that the documentation > is less than perfect. It might make sense to clean up the documentation > first to ensure that it matches what it is actually meant to document. I'm not sure you wrote here what you intended to write?! > Sure, I understand, the devicetree bindings are supposed to be > implementation independent. We all know that this is an ideal view > which often does not match reality, as the code tends to be written > first and the devicetree bindings tend to be an afterthought. I think for drivers that work with a single type of device it works well the other way round. But for something as generic as a gpio watchdog that is supposed to drive several different types of devices I think agreeing on which way to go is more time saving than to come up with an implementation first that then needs change on feedback. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ | -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
