On Sun, 7 Oct 2018 16:18:08 +0100 Jonathan Cameron <[email protected]> wrote:
> On Tue, 2 Oct 2018 22:38:11 +0800 > Song Qiang <[email protected]> wrote: > > > Signed-off-by: Song Qiang <[email protected]> > > --- > > .../bindings/iio/magnetometer/pni,rm3100.txt | 20 +++++++++++++++++++ > > 1 file changed, 20 insertions(+) > > create mode 100644 > > Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt > > > > diff --git > > a/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt > > b/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt > > new file mode 100644 > > index 000000000000..4677690fc5d0 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt > > @@ -0,0 +1,20 @@ > > +* PNI RM3100 3-axis magnetometer sensor > > + > > +Required properties: > > + > > +- compatible : should be "pni,rm3100" > > +- reg : the I2C address or SPI chip select number of the sensor. > > + > > +Optional properties: > > + > > +- interrupts: data ready (DRDY) from the chip. > > + The interrupts can be triggered on rising edges. > From Phil's response this appears to be incorrect and > it's actually a level sensitive interrupt. > I haven't checked the data sheet to confirm this. > > That'll bring all sorts of pain if you have a host that can only > do edge sensitive so I'm hoping that's not true for you > (edge sensitive only interrupts on hosts are pretty unusual > though it cause me a lot of problems when I started out > with IIO years ago :( > > The docs aren't super clear on this. The subtlety is > whether there is a guaranteed 'low' time between reading the > data and it going high again due to another reading. This usually > only matters if you are running very quickly though so may be > fine here. > > This will only become relevant with continuous mode if you > add support for that later (I think!) I realised just after I sent this that I was being unclear. If you aren't doing continuous mode and hence have a fairly strong guarantee of a decent gap between reads, you may be able to get away with supporting either LEVEL or EDGE interrupts. In continuous mode, it is necessary to have a minimum low time for EDGE interrupts to work. Jonathan > > Jonathan > > > + > > +Example: > > + > > +rm3100: rm3100@20 { > > + compatible = "pni,rm3100"; > > + reg = <0x20>; > > + interrupt-parent = <&gpio0>; > > + interrupts = <4 IRQ_TYPE_EDGE_RISING>; > > +}; >
