Re: IIO Driver for TMP117 Temperature sensor

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On Sun, Dec 13, 2020 at 10:20 PM Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
>
> On Sun, 13 Dec 2020 08:08:26 -0800
> Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> > On 12/13/20 7:12 AM, Jonathan Cameron wrote:
> > > On Wed, 9 Dec 2020 11:48:40 -0800
> > > Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> > >
> > >> On 12/9/20 12:11 AM, Alexandru Ardelean wrote:
> > >>> On Tue, Dec 8, 2020 at 6:10 PM Puranjay Mohan <puranjay12@xxxxxxxxx> wrote:
> > >>>>
> > >>>> I have this TI's TMP117 sensor with me and I was thinking about writing an
> > >>>> IIO driver for it as a hobby project. Is the IIO subsystem the correct
> > >>>> place for this driver? if yes, can someone help me get started with this,
> > >>>> I haven't written an IIO driver before. I have this sensor and also a
> > >>>> raspberry pi with me for testing.
> > >>>
> > >>> This could also fit into drivers/hwmon.
> > >>> Looking at the HWMON subsystem there are more TMP drivers there
> > >>> (TMP102/103/108/401/513).
> > >>> The first 3 seem a bit more similar to TMP117 (in terms of register map).
> > >>>
> > >>
> > >> It would probably be better suited for hwmon (it has limit registers,
> > >> suggesting a common use as hardware monitoring device).
> > > It is a curious part.  I suspect TI based their design for a medical grade
> > > digital thermometer chip on an existing hwmon part.
> > >
> > > The limit registers are very simple so could be supported by IIO.
> > > This sits somewhere in the middle of high end thermocouple chips which
> > > tend to be in IIO and typically lower accuracy / range hwmon parts.
> > >
> > > It's in the fuzzy borderline region so I doubt anyone would raise strong
> > > objections to which subsystem it was in.  Guenter has fallen on the
> > > hwmon side of things and I'm fine with that.
> > >
> >
> > On the other side, it turns out that there is already tmp107 support
> > in iio, and tmp107 is pretty much the spi equivalent of the same chip.
> > So it really depends on the use case. If the user wants to use the iio
> > subsystem, I am fine with it. We just need to remind people that this
> > implies no or only limited hwmon support.
> >
> > [ I really need to spend the time to write a hwmon->iio bridge.
> >   The iio->hwmon bridge is a bit limited - I have not been able to
> >   figure out how to support limit registers (or event values)
> >   and events, and I don't think it is possible. ]
>
> So far IIO doesn't have an in kernel consumer interface for
> events. It shouldn't be that hard to add one though and it
> has been on the todo list for a very long time.  We've discussed
> it a few times and concluded that there are some short cuts such
> as sending all events to all consumers and relying on the receiver
> to do any necessary filtering. It's a bit messy but it makes for
> much simpler core code.
>
> Maybe I'll get bored enough over xmas to look at it...
>

Hi Jonathan,
Where can I access this TODO list, I would like to do some tasks on it.
I am a novice but I might be able to solve the easier tasks.

> Jonathan
>
> >
> > Guenter
> >
> > > Jonathan
> > >
> > >>
> > >>> Let's see what others have to add.
> > >>> But, all-in-all whatever driver you end up writing, the easiest method
> > >>> is to copy an existing similar driver and extend it.
> > >>> Sometimes, a part can be added to an existing driver.
> > >>> At a quick scan through existing drivers, it doesn't look like TMP117
> > >>> is similar to existing drivers, so it may require a new driver
> > >>> altogether.
> > >>
> > >> I don't see an immediate match either, but the tmp102 hwmon driver
> > >> might be a good start.
> > >>
> > >> Guenter
> > >>
> > >>> I may have missed something though.
> > >>>
> > >>> Thanks
> > >>> Alex
> > >>>
> > >>>>
> > >>>> --
> > >>>> Thanks and Regards
> > >>>>
> > >>>> Yours Truly,
> > >>>>
> > >>>> Puranjay Mohan
> > >>
> > >
> >
>


-- 
Thanks and Regards

Yours Truly,

Puranjay Mohan



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