Re: GSoC Proposal 2022

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Tue, 12 Apr 2022 16:23:55 +0200
Nuno Sá <noname.nuno@gmail.com> wrote:

> On Tue, 2022-04-12 at 09:24 -0300, Maíra Canal wrote:
> > On 04/12, Nuno Sá wrote:  
> > > On Tue, 2022-04-12 at 11:48 +0300, Andy Shevchenko wrote:  
> > > > On Tue, Apr 12, 2022 at 10:43 AM Maíra Canal <maira.canal@usp.br>
> > > > wrote:  
> > > > > On 04/11, Jonathan Cameron wrote:  
> > > 
> > > The MAX31875 looks to be a fairly simple one (maybe a good
> > > candidate
> > > for a first driver) but, IMO, having it in IIO boils down to have
> > > support for continuos mode which would mean triggered buffer
> > > support.  
> > 
> > I took another look at the Maxim Integrated catalog and end up
> > finding
> > the MAX31889 Temperature Sensor.
> > 
> > I guess this sensor has an interesting challenge level with the need
> > to
> > implement FIFO and interrupts support. 
> > 
> > Have you guys some thoughts on this one?
Hmm. The fifo is interesting, but I'm somewhat doubtful that it's actually
much use when connected to a linux system.  The sampling rate is 1Hz.
At that rate even in busy systems or low power situations, there is
little reason not to just poll the device.

You 'could' wire up a PWM or similar to the gpio and have it operate
like a 'self clocked' device but with sampling rates so low it's a fairly
contrived situation.

Temperature sensors in general are often a bad fit for IIO precisely because
they are mostly designed for monitoring type purposes which HWMON covers.
The exceptions are high speed or high accuracy devices or weird ones like
infrared thermometers.

For the corner cases we have the option of the iio-hwmon bridge driver
but they need to be more obviously not suited to hwmon than this one to
justify their presence in IIO. In general hwmon drivers are simpler, so
if you can get away with it they are a better choice. (also some hwmon
specific features like multiple levels of even of the same type for
warning / critical detection).

Jonathan

> >   
> 
> At first glance, it looks like a better choice when compared with
> MAX31875...
> 
> - Nuno Sá
> >   
> > >   
>