Message-ID: <4FC1159F.7090606@cam.ac.uk>
Date: Sat, 26 May 2012 18:40:47 +0100
From: Jonathan Cameron <jic23@cam.ac.uk>
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To: =?ISO-8859-1?Q?=C9ric_Piel?= <eric.piel@tremplin-utc.net>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Darren Hart <dvhart@linux.intel.com>,
        "lkml, " <linux-kernel@vger.kernel.org>,
        Jonathan Cameron <jic23@kernel.org>,
        Lars-Peter Clausen <lars@metafoo.de>,
        Carmine Iascone <carmine.iascone@st.com>,
        Matteo Dameno <matteo.dameno@st.com>
Subject: Re: LIS331DLH accelerometer driver, IIO or not?
References: <4FBF0AC1.6030406@linux.intel.com> <20120525051051.GA3135@kroah.com> <4FC0C422.8080605@tremplin-utc.net>
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On 05/26/2012 12:53 PM, ?ric 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., I?C, 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

Jonathan
> 
> Cheers,
> ?ric

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