On Fri, Aug 05, 2011 at 12:33:31PM -0700, Stephen Warren wrote: > Russell King - ARM Linux wrote at Friday, August 05, 2011 1:15 PM: > > On Fri, Aug 05, 2011 at 08:43:20AM -0700, Stephen Warren wrote: > > > Russell King - ARM Linux wrote at Friday, August 05, 2011 3:40 AM: > > > > On Thu, Aug 04, 2011 at 05:00:17PM -0600, Stephen Warren wrote: > > > > > In http://www.spinics.net/lists/linux-tegra/msg01731.html, Mark Brown > > > > > pointed out that it was a little silly forcing every board or driver > > > > > to gpio_request() a GPIO that is later converted to an IRQ, and passed > > > > > to request_irq. The first patch in this series instead makes the core > > > > > IRQ code perform these calls when appropriate, to avoid duplicating it > > > > > everywhere. > > > > > > > > Trying to go from IRQ to GPIO is not a good idea - most of the > > > > IRQ <-> GPIO macros we have today are just plain broken. Many of them > > > > just add or subtract a constant, which means non-GPIO IRQs have an > > > > apparant GPIO number too. Couple this with the fact that all positive > > > > GPIO numbers are valid, and this is a recipe for wrong GPIOs getting > > > > used and GPIOs being requested for non-GPIO IRQs. > > > > > > > > I think this was also discussed in the past, and the conclusion was that > > > > IRQs should be kept separate from GPIOs. Maybe views have changed since > > > > then... > > > > > > > > However, if we do want to do this, then it would be much better to provide > > > > a new API for requesting GPIO IRQs, eg: > > > > > > > > gpio_request_irq() > > > > > > > > which would wrap around request_threaded_irq(), takes a GPIO number, > > > > does the GPIO->IRQ conversion internally, and whatever GPIO setup is > > > > required. Something like this: > > > > > > With that approach, drivers need to explicitly know whether they're > > > passed a GPIO or an IRQ, and do something different, or they need to > > > choose to only accept a GPIO or IRQ. > > > > You completely missed the biggest reason why your approach is broken. > > No, I didn't. Yes you did. > I was discussing whether an alternative API for IRQ registration > would work, and I was pointing out some problems with it. > > That has nothing to do with whether my original proposal is workable. And that proves that you missed the point. I am suggesting an alternative solution precisely because your original proposal is unworkable. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
