On Sun, Apr 12, 2015 at 6:55 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: > On 10/04/15 12:08, Daniel Baluta wrote: >> On Thu, Apr 9, 2015 at 8:15 PM, Jonathan Cameron <jic23@xxxxxxxxxx> wrote: >>> On 06/04/15 15:18, Daniel Baluta wrote: >>>> This module is the core of IIO configfs. It creates the "iio" subsystem under >>>> configfs mount point root, with one default group for "triggers". >>>> >>>> It offers basic interface for registering software trigger types. Next patches >>>> will add "hrtimer" and "sysfs" trigger types. To add a new trigger type we must >>>> create a new kernel module which implements iio_configfs_trigger.h interface. >>>> >>>> See Documentation/iio/iio_configfs.txt for more details on how configfs >>>> support for IIO works. >>>> >>>> Signed-off-by: Daniel Baluta <daniel.baluta@xxxxxxxxx> >>> Looks good and is actually a fair bit simpler than I expected which is nice! >>> As an ideal aim, I'd like there to be no need for the core to have any >>> idea what triggers exist and can be registered (beyond preventing naming >>> clashes etc). Actually, not much would be needed to implement that I think, just >>> using a list and looking up in it (we aren't on a particularly fast path so >>> don't need anything clever) instead of a simple array. A touch of locking >>> probably to avoid two many simultaneous users of that list... >> >> Good point. Will do. >> >> I will create a list holding the list with the registered trigger types using >> the trigger type name as the searching key (e.g. : "hrtimer", "sysfs"). >> >>> >>> Hmm. having read through the patches, are we fundamentally limited to having to >>> specify the entire directory structure before bringing up configfs? >> >> AFAIK, directories can be created in two ways: >> >> * as default groups registered at iio trigger configfs init time. >> * when userspace applications call mkdir. >> >> So, unless we agree that userspace applications should be aware of IIO >> trigger types and manually call mkdir /config/iio/triggers/hrtimer (for example) >> we are limited to specifying the entire directory structure in the IIO >> configs module. > That's my understanding as well and the reason the usb gadget stuff > uses <type>-instancename instead of type/instancename > > At the moment I think we will need to go the same way. > Of course from the point of view of what userspace needs to know > it's actually the same as > > mkdir hrtimer > cd hrtime > mkdir instancename > though so perhaps we should just do that. Ok, I see your point here. I will try to send a new version with this in mind. -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
