On Sun, 2018-01-14 at 12:56 +0000, Jonathan Cameron wrote: > On Wed, 10 Jan 2018 13:29:56 +0200 > <alexandru.ardelean@xxxxxxxxxx> wrote: > > > From: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> > > > > Document the device-tree bindings of the "ad7192" driver. > > Added datasheet references for supported devices, > > explanation for each property supported by the driver, > > and an example. > > > > Signed-off-by: Alexandru Ardelean <alexandru.ardelean@xxxxxxxxxx> > > --- > > .../staging/iio/Documentation/adc/adi,ad7192.txt | 71 > > ++++++++++++++++++++++ > > 1 file changed, 71 insertions(+) > > create mode 100644 > > drivers/staging/iio/Documentation/adc/adi,ad7192.txt > > > > diff --git a/drivers/staging/iio/Documentation/adc/adi,ad7192.txt > > b/drivers/staging/iio/Documentation/adc/adi,ad7192.txt > > new file mode 100644 > > index 000000000000..1f8f769a003f > > --- /dev/null > > +++ b/drivers/staging/iio/Documentation/adc/adi,ad7192.txt > > @@ -0,0 +1,71 @@ > > +Analog Devices AD719x ADC Driver > > + > > +Reference: > > +[1] http://www.analog.com/en/products/analog-to-digital-converters > > /ad7190.html > > +[2] http://www.analog.com/en/products/analog-to-digital-converters > > /ad7192.html > > +[3] http://www.analog.com/en/products/analog-to-digital-converters > > /ad7193.html > > +[4] http://www.analog.com/en/products/analog-to-digital-converters > > /ad7195.html > > + > > +Required properties: > > + - compatible: Should be "adi,ad7190", "adi,ad7192", "adi,ad7193" > > + or "adi,ad7195" > > + - reg: SPI chip select number for the device > > + - spi-cpol, spi-cpha: Controller support only mode 3, so both > > spi-cpol > > + and spi-cpha should be present > > + - spi-max-frequency: Definition as per > > + see: Documentation/devicetree/bindings/spi/spi-bus.txt > > + - interrupt-parent: phandle to the parent interrupt controller > > + see: Documentation/devicetree/bindings/interrupt- > > controller/interrupts.txt > > + - interrupts: IRQ line for the ADC > > + see: Documentation/devicetree/bindings/interrupt- > > controller/interrupts.txt > > + > > +Recommended properties: > > + - adi,clock-source-select: sets the clock source to be used; > > values are > > + * 0 - external crystal, connected from pin MCLK1 to MCLK2 > > + * 1 - external clock, applied to MCLK2 pin > > + * 2 - internal 4.92 Mhz clock; pin MCLK2 is tristated (default) > > + * 3 - internal 4.92 Mhz clock; internal clock is available on > > MCLK2 > > For the external clock there are standard bindings > Documentation/devicetree/bindings/clock/clock-bindings.txt > If one is specified assume it should be used. > > For the crystal a quick grep suggests that clocknames are used in > somecases > at least to distinguish between osc and xtal. ack will use clock bindings > > Final pair probably need a specific devicetree binding like > adi,clockout or something... (not thought much on that name!) > > > > + - adi,external-clock-Hz: if "adi,clock-source-select" is value > > '1', > > + this value should be specified to the ADC > > + - avdd-supply: Analog Supply Voltage, 4.75V to 5.25V. AVDD is > > + independent of DVDD > > + - dvdd-supply: Digital Supply Voltage, 2.7V to 5.25V. DVDD > > + is independent of AVDD > > Regulators not values + add a cross reference to the regulator docs. > I would make this required rather than optional. Easy to supply > fixed regs in devicetree if it makes sense and will simplify > things in the long run if we know they are awlays there. > > ack > > + > > +Optional properties: > > + - adi,refin2-pins-enable: select external reference to be > > applied > > + to P1,REFIN2(+) & P0,REFIN2(-) pins instead of REFIN1(+) & > > REFIN1(-); > > + not available for "ad7195" > > + - adi,rejection-60-Hz-enable: enables simultaneous 50/60 Hz > > rejection > > + - adi,chop-enable: enable chop to minimize ADC offset and offset > > drift > > + - adi,buffer-enable: enables the buffer on the analog inputs > > + - adi,burnout-currents-enable: when selected, the 500 nA current > > sources > > + in the signal path are enabled; can be enabled only when buffer > > is active > > + and chop is disabled > > These are an oddity. I'm unclear on whether you would ever have them > on > all the time. Sounds like detection hardware that you'd run in an > initial > self test to check your transducer isn't blown. > they're chip-settings done at init time the names may need some work, maybe even the types ; it could be that these may even work at runtime, in which case, a sysfs binding may be more interesting i'd have to investigate more in-depth > > > + - adi,sinc3-filter-enable: enables the SINC3 filter; if unset > > + the SINC4 digital filter is used after the modulator > > so this is a selection between two filters. Good if the naming > implies this.. > > > + - adi,unipolar-enable: when this is set voltage ranges must be > > unipolar > > + (e.g 0 to 5V) versus bipolar voltage ranges (e.g. -5V to 5V) > > That isn't close to what I'm reading from the datasheet. > > "A bipolar input range does not > imply that the part can tolerate negative voltages with respect to > system AGND. " > > This is about using a second input as the differential negative vs > using > the common reference input... will re-visit i'll admit this stuff is not yet my forte, but I'll make an effort to learn > > > + > > +Example: > > +ad7190@0 { > > + compatible = "adi,ad7190"; > > + reg = <0>; > > + spi-max-frequency = <1000000>; > > + spi-cpol; > > + spi-cpha; > > + > > + #interrupt-cells = <2>; > > + interrupts = <25 0x2>; > > + interrupt-parent = <&gpio>; > > + avdd-supply = <&adc_avdd>; > > + > > + adi,clock-source-select = /bits/ 8 <0>; > > + > > + adi,refin2-pins-enable; > > + adi,rejection-60-Hz-enable; > > + adi,buffer-enable; > > + adi,burnout-currents-enable; > > + adi,sinc3-filter-enable; > > + adi,unipolar-enable; > > +}; > > ��.n��������+%������w��{.n����z�{��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
