On Wed, Sep 17, 2014 at 05:36:31PM +0100, Jonathan Cameron wrote: > > > On September 9, 2014 1:04:30 AM GMT+01:00, Darren Hart <dvhart@xxxxxxxxxxxxx> wrote: > >On Fri, Sep 05, 2014 at 11:04:18PM -0600, Azael Avalos wrote: > >> Hi there, > >> > >> 2014-09-05 20:42 GMT-06:00 Darren Hart <dvhart@xxxxxxxxxxxxx>: > >> > On Fri, Sep 05, 2014 at 11:14:05AM -0600, Azael Avalos wrote: > >> >> The accelerometer sensor is very sensitive, and having userspace > >> >> poll the sysfs position entry is not very battery friendly. > >> >> > >> >> This patch removes the sysfs entry and instead, it creates an > >> >> input polled device (joystick) for the built-in accelerometer. > >> > > >> > Hrm, while sysfs details can change across kernel versions, usually > >due to > >> > driver core changes, we try to keep them as consistent as possible > >so as not to > >> > break userspace. > >> > > >> > That said, if we are going to try and come up with a better model > >for > >> > representing an accelerometer, wouldn't treating it as an IIO > >device be the more > >> > logical approach? > >> > >> Yes of course, but the actual accelerometer device (sensor?) is not > >> really exposed, > >> only certain "functions" it provides, and they are divided across two > >> different ACPI devices, > >> TOS620A exposes the protection, and the TOS1900 (and et. al.) only > >> exposes the axes. > > > >As I understand it, IIO defines an interface to a device, a standard > >sysfs set > >of properties. I should think we could provide the appropriate > >callbacks even > >for a partially implemented (or a pair of) accelerometer. > > > >Jonathan, what are your thoughts here. Is such a "device" (ACPI > >accessors to > >axis and threshold) a candidate for IIO, or is this input polled device > >more > >appropriate? > Absolutely fine in IIO. > > Sorry I took so long to reply. Read the title and expected more detailed issue so queued > it up for when I had more time. Oops. > > Only slight gotcha is that there is some debate over the iio timer trigger > configuration interface which would be equivalent of a polled input device. > > Hence it hasn't merged yet. > Comes down to how these are instantiated. Lars-Peter Clausen is planning a configfs > proposal rather than how we do the user space trigger creation currently. > > A user space trigger would work but then you loose lack of hitting sysfs files. Thanks Jonathan, Azael, please follow-up with the IIO folks and if you want to modify the interface, please do so via IIO so it uses a consistent interface and we can eliminate these custom sysfs files. Thanks, -- Darren Hart Intel Open Source Technology Center -- 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
