On Fri, Feb 01, 2019 at 10:12:31AM +0100, Johan Hovold wrote: > On Thu, Jan 31, 2019 at 09:40:04PM +0100, Tomasz Duszynski wrote: > > On Wed, Jan 30, 2019 at 10:12:54AM +0100, Johan Hovold wrote: > > > On Mon, Jan 28, 2019 at 07:43:33PM +0100, Tomasz Duszynski wrote: > > > > On Mon, Jan 28, 2019 at 08:58:19AM +0100, Johan Hovold wrote: > > > > > On Sun, Jan 27, 2019 at 07:19:16PM +0100, Tomasz Duszynski wrote: > > > > > > Add device tree support for Plantower PMS7003 particulate matter sensor. > > > > > > > > > > > > Signed-off-by: Tomasz Duszynski <tduszyns@xxxxxxxxx> > > > > > > --- > > > > > > .../iio/chemical/plantower,pms7003.txt | 19 +++++++++++++++++++ > > > > > > 1 file changed, 19 insertions(+) > > > > > > create mode 100644 Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt > > > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt > > > > > > new file mode 100644 > > > > > > index 000000000000..e4c7f2fb1e30 > > > > > > --- /dev/null > > > > > > +++ b/Documentation/devicetree/bindings/iio/chemical/plantower,pms7003.txt > > > > > > @@ -0,0 +1,19 @@ > > > > > > +* Plantower PMS7003 particulate matter sensor > > > > > > + > > > > > > +Required properties: > > > > > > +- compatible: must be "plantower,pms7003" > > > > > > + > > > > > > +Optional properties: > > > > > > +- vcc-supply: phandle to the regulator that provides power to the sensor > > > > > > > > > > Shouldn't this one be a required property? > > > > > > > > > > > > > Driver does not use regulator framework hence to me this property fits > > > > here better. > > > > > > The device tree describes hardware, not any particular driver. > > > > > > That said, there is a bit of an on-going debate on whether mandatory > > > supplies (from a hardware perspective) should always be represented in > > > device tree or not. > > > > > > https://lore.kernel.org/lkml/20181123133126.GF2089@xxxxxxxxxxxxx/T/#u > > > https://lore.kernel.org/lkml/20180409102244.GB11532@xxxxxxxxxxxxx/T/#u > > > https://lore.kernel.org/lkml/20180425171123.xhyoay3nu463btoq@rob-hp-laptop/T/#u > > > > > > > Even after going through this threads I am still unconvinced that > > vcc-supply should be a requirement. Making this a mandatory property > > would automatically imply using *_regulator_get() in a driver code > > (on condition one is adding regulator support). In case there > > isn't any physically connected we end up with a dummy one and a warning. > > How would the device work at all without a physical vcc supply? > I meant the discrete IC regulator. > > Is it how this should work? > > As Mark mentioned in the threads above, you could add a fixed, > always-on regulator for cases where the device is always powered. > > Boards failing to describe this supply would still work on Linux, but > would end up with a dummy regulator and a warning. > Fair enough. > > > > > > +- set-gpios: phandle to the GPIO connected to the SET line > > > > > > +- reset-gpios: phandle to the GPIO connected to the RESET line > > > > > > + > > > > > > +Refer to serial/slave-device.txt for generic serial attached device bindings. > > > > > > + > > > > > > +Example: > > > > > > + > > > > > > +&uart0 { > > > > > > + pms7003 { > > > > > > > > > > The node name should be generic and reflect the functionality rather > > > > > than model. Perhaps "pms" will do here. > > > > > > > > Agree, ideally we should have a generic dt name for this kind of sensors > > > > (something like air-pollution-sensor perhaps?). But unfortunately there isn't > > > > anything available now so I guess compatible part name should be okay > > > > (besides this is the type of naming commonly used in other iio bindings). > > > > > > What's wrong with particulate matter sensor ("pms")? > > > > > > Seems like a better fix than any particular model name to me at least. > > > > > > > Personally I would vote for a more descriptive node name, for example: > > particulate-matter-sensor or air-pollution-sensor or other name > > which clearly shows what device we are dealing with. > > Spelling it out seems preferable, yes. You know the domain better than > I do; I only suggest you come up with a generic node name. > > Johan
