Re: [PATCH] Add STMicroelectronics LPS001WP pressure sensor device driver into misc

[Guenter Roeck <guenter.roeck@ericsson.com>]

On Mon, Mar 14, 2011 at 05:42:44PM -0400, Jean Delvare wrote:
> On Mon, 14 Mar 2011 21:36:43 +0100, Arnd Bergmann wrote:
> > On Monday 14 March 2011 21:18:09 Jean Delvare wrote:
> > > Jonathan is correct. Pressure sensors are not hardware monitoring
> > > devices, their drivers have nothing to do in drivers/hwmon. This is
> > > something for drivers/misc or staging/iio.
> > 
> > I generally try to prevent people from adding more ad-hoc interfaces
> > to drivers/misc. Anything that is called a drivers/misc driver to me
> > must qualify as "there can't possibly be a second driver with the
> > same semantics", otherwise it should be part of another subsystem
> > with clear rules, or be put into its own file system.
> 
> I see drivers/misc differently. I see it as "not enough drivers of the
> same type to justify a new subsystem". So I encourage people to put
> things there in the absence of any suitable subsystem, until someone
> gets enough motivation to start such a subsystem. This is more
> pragmatic than requesting subsystems to be created upfront.
> 
Agreed.

Note that there is already a pressure sensor in drivers/misc - bmp085.c.
That chip also includes a temperature sensor.

> That being said, staging is another option nowadays.
> 
> > While it seems that right now everyone is just trying to keep move
> > the driver to some other subsystem, I think it's worth noting that
> > it is indeed a useful thing to have the driver, I'm optimistic
> > that we can find some place for it. ;-)
> > 
> > Now how about the IIO stuff? This is the first time I've even
> > heard about it. Does it have any major disadvantages besides
> > being staging-quality?
> 
> This is indeed the major disadvantage. IIO seems to take a lot of time
> to move out of staging, although I don't know what the current ETA is.
> 
In general it would be nice to have a "sensors" subsystem. iio is going into
that direction, so creating another one might not make much sense at this point.

Guenter