On Mon, 2019-05-06 at 14:46 +0300, Alexandru Ardelean wrote: > This patch adds a YAML binding for the Analog Devices ADXL345 I2C/SPI > accelerometer. > > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> > --- > > And now for the RFC part. > Normally, I would dig into source-code to try to figure this out, but at > this point-in-time, I am low on time/energy to do this. > And maybe this helps trigger a discussion about this. > > Apologies if this has been coverted on the devicetree mailing list, but > at least we'd get some coverage on the IIO list (with this). > > The ADXL345 device (as others) supports both I2C & SPI interfaces. > > Question1: do we write 2 YAML files, or 1 ? I was looking at Zephyr (for > some ideas/reference) but it seems to me that the YAML DT binding format > is > different than this one ? They write 2 files for ADXL372 (1 for SPI, 1 > for > I2C). > > Question1-a: one thing is that SPI requires some props to be `required` > that would not be required for the I2C binding. This could be solved by > doing 2 files, but if doing 1 YAML file, is there a way to do conditional > `required` ? i.e. property is required if `SPI` ? not sure how to check > for > SPI vs I2C, it would be interesting (at some point) to somehow enforce > SPI/I2C bindings correctness. > > Question2: `make dt_binding_check` seems to generate only the first > example. Is this known behavior, or do I need to take something else into > consideration ? > > Question3: one idea that was neat in Zephyr, is that there is a > 'inherits' > + `!include` mechanism for including common SPI & I2C device stuff. It > would be neat to have this. Is there a way to do this now, or maybe this > would come later ? Maybe, just having a way to include a YAML file into > another would be interesting. > > .../bindings/iio/accel/adi,adxl345.yaml | 63 +++++++++++++++++++ > 1 file changed, 63 insertions(+) > create mode 100644 > Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml > > diff --git a/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml > b/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml > new file mode 100644 > index 000000000000..246b90c07aaa > --- /dev/null > +++ b/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml > @@ -0,0 +1,63 @@ > +# SPDX-License-Identifier: GPL-2.0 > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/iio/accelerometers/adi,adxl345.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Analog Devices ADXL345/ADXL375 3-Axis Digital Accelerometers > + > +maintainers: > + - Michael Hennerich <michael.hennerich@xxxxxxxxxx> > + > +description: | > + Driver for Analog Devices ADXL345/ADXL375 3-Axis Digital > Accelerometers > + http://www.analog.com/en/products/mems/accelerometers/adxl345.html > + > http://www.analog.com/en/products/sensors-mems/accelerometers/adxl375.html > + > +properties: > + compatible: > + oneOf: > + - items: > + - enum: > + - adi,adxl345 > + - adi,adxl375 > + > + reg: > + description: > + The I2C address or SPI chip select number of the sensor > + maxItems: 1 > + > + spi-cpha: > + description: > + SPI clock phase must be set, to select SPI mode 3 > + > + spi-cpol: > + description: > + SPI clock polarity must be set, to select SPI mode 3 > + > + interrupts: > + description: > + A variable number of interrupts warrants a description of what > conditions > + affect the number of interrupts. Otherwise, descriptions on > standard > + properties are not necessary. > + oops, since i left this un-changed oh, well, it's an RFC anyway :) it would have received a V2 anyway > +required: > + - compatible > + - reg > + > +examples: > + - | > + /* Example for a I2C device node */ > + accelerometer@2a { > + compatible = "adi,adxl345"; > + reg = <0x53>; > + }; > + - | > + /* Example for a SPI device node */ > + accelerometer@0 { > + compatible = "adi,adxl345"; > + reg = <0>; > + spi-max-frequency = <5000000>; > + spi-cpol; > + spi-cpha; > + };
