Re: [PATCH 0/2] iio: Heart Rate Monitors

[Andrew F. Davis]

On 11/01/2015 12:35 PM, Jonathan Cameron wrote:
> On 31/10/15 16:31, Andrew F. Davis wrote:
> > Hello all,
> >
> > This series adds the TI AFE4404 "Ultra-small, Integrated AFE for
> > Wearable, Optical Heart Rate Monitoring and Bio-Sensing".
> >
> > This work is based on previous work by Dan Murphy [0] who is working
> > on other tasks at the moment, so I will be helping to continue
> > upstreaming this driver. This is more of a re-write than a continuation
> > and there are many changes so I am submitting this as a v1.
> >
> > This device is very similar to the AFE4403 and I was originally planning
> > on pushing the two drivers together with common core functions in a
> > third file. The AFE4403 driver is still being tested so I merged common
> > code back into this driver, this is why this driver may seem a bit
> > unnecessarily modular. I will probably split this stuff back out when
> > I push the AFE4403.
> >
> > I also had some issues with sysfs naming for the channels; this device
> > has three input channels from three LED stages and two ambient
> > channels based on the LED stages. This might have been be a good place
> > for using IIO modifiers[1], but we also have two differential channels
> > based on the ambient channels, and channels cannot have both modifiers
> > and be differential (the modifier is stored in the differential channel's
> > ID field?).
> True enough. Didn't expect to run into this particular problem, but I guess
> someone will always make hardware breaking any assumptions we make from the
> software side of things.

Seems that way, it probably would work to have modified be more that a single
bit flag, maybe call it modifier and just store the modifier in there. Doesn't
look like it would be that hard right now to fix.

I'm not really sure I understand the need for modifiers at all really, seems
most are used by a single driver to get around just naming the channel.

> > So I used sysfs names that would be close to what they
> > would be if IIO supported these things.
> Fair enough as a starting point though we probably want to figure out how
> to do this 'right'.   Adding an extra field to the channel descriptor will
> be easy enough - it'll be event codes that are nasty to handle.
>
> Jonathan
> > [0] http://www.spinics.net/lists/linux-iio/msg18413.html
> > [1] IIO_MOD_TEMP_AMBIENT could be renamed IIO_MOD_AMBIENT as it can
> > also apply to LIGHT, PRESSURE, HUMIDITY, etc..
> No problem with this change so please send a patch.
> > Thanks,
> > Andrew
> >
> > Andrew F. Davis (2):
> >    Documentation: afe4404: Add DT bindings for the AFE4404 heart monitor
> >    iio: health: Add driver for the TI AFE4404 heart monitor
> >
> >   .../ABI/testing/sysfs-bus-iio-health-afe4404       |  70 +++
> >   .../devicetree/bindings/iio/health/afe4404.txt     |  27 ++
> >   drivers/iio/Kconfig                                |   1 +
> >   drivers/iio/Makefile                               |   1 +
> >   drivers/iio/health/Kconfig                         |  24 +
> >   drivers/iio/health/Makefile                        |   6 +
> >   drivers/iio/health/afe4404.c                       | 526 +++++++++++++++++++++
> >   drivers/iio/health/afe440x.h                       | 159 +++++++
> >   8 files changed, 814 insertions(+)
> >   create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-health-afe4404
> >   create mode 100644 Documentation/devicetree/bindings/iio/health/afe4404.txt
> >   create mode 100644 drivers/iio/health/Kconfig
> >   create mode 100644 drivers/iio/health/Makefile
> >   create mode 100644 drivers/iio/health/afe4404.c
> >   create mode 100644 drivers/iio/health/afe440x.h
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