Messages in this thread |  | | | Date | Sat, 26 May 2012 20:14:19 -0700 | | From | Darren Hart <> | | Subject | Re: LIS331DLH accelerometer driver, IIO or not? |
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On 05/26/2012 10:40 AM, Jonathan Cameron wrote: > On 05/26/2012 12:53 PM, Éric Piel wrote: >> On 25-05-12 07:10, Greg Kroah-Hartman wrote: >>> On Thu, May 24, 2012 at 09:29:53PM -0700, Darren Hart wrote: >>>> I'm working to enable the LIS331DLH accelerometer on the Fish River >>>> Island II embedded atom development kit. >>>> >>>> I am more interested in enabling people to do bizarre and interesting >>>> things with the device, so I'm leaning toward continuing with my IIO >>>> implementation. >>> >>> Make it an IIO driver and then we can delete the misc driver, which >>> shouldn't have snuck in there in the first place :) >>> >> >> To be more fair to the misc driver, I wouldn't say it snucked in there, >> but more "it ended up there as the least worse place" ;-) Actually, the >> main problem is that there seemed to be no maintainer interested in >> taking care of accelerometer devices. Now that the IIO subsystem is out >> of staging, it might be a right place. That said, I don't know much >> about the user interface to IIO. I know that I liked the idea of having >> an joystick device created for an accelerometer because that allows to >> get many programs to access the device almost without any modifications. > I agree that this sort of device should have an input interface. Not > sure if a joystick is the right option, but that's more one for Dmitry > to comment on. >> >> I'd happy to help merge the lis3lv02d driver into IIO. IMHO, the main >> steps are: >> * make sure all the various buses are supported (e.g., I²C, SPI, and >> also "ACPI-HP") >> * ensure the various versions of the accelerometer are supported (there >> are 3 supported currently) >> * check that the driver is automatically loaded on HP laptops (via ACPI >> entry) >> * for each of the current interfaces decide if they should be ported or >> dropped (/dev/js*, /dev/freefall, sysfs...) >> >> What do you think Jonathan? > You've laid it out extremely clearly. Thanks, I agree with these steps, > though they may occur from a slightly different angle given Darren is > interested in a part that is not (I believe) currently supported by > your existing driver. Hence he may initially want to do a separate > driver with that (keeping in mind the aim of mergining in the existing > driver). I have an ancient driver for the lis3l02dq alone (in > iio from the start) that will also get eaten up by Daren's new driver > (and the ability to test on that part on spi). > staging/iio/accel/lis3l02dq*.c
I think I should start with getting the lis331dlh support completed, if for no other reason than to keep the scope manageable as I write my first real driver. From that I would like to merge in Jonathan's IIO lis3l02dq driver to get the multi-chip support part right. Then we should look at expanding the scope of the interface and finally merging with misc/lis3102dq. I believe that should meet with everyone's suggestions.
One thing I would like to understand better is what sort of interface does userspace current expect. Phone Gap, for example, provides a very high level interface to applications in m/s^2 for each axis. Is there some interface we should ensure all accelerometer driver's implement?
I suspect a /dev/accel interface that reads out xyz values in ms/s^2 would make sense. We would need to ensure that allows for polled as well as event driven. Thoughts?
-- Darren Hart Intel Open Source Technology Center Yocto Project - Linux Kernel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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