On Fri, 27 Nov 2020 20:42:40 +0100 <tomislav.denis@xxxxxxx> wrote: > From: Tomislav Denis <tomislav.denis@xxxxxxx> > > Add a device tree binding documentation for Texas Instruments > ADS131E0x ADC family driver. > > Signed-off-by: Tomislav Denis <tomislav.denis@xxxxxxx> Hi Tomislav, A few comments inline. Thanks, Jonathan > --- > .../devicetree/bindings/iio/adc/ti,ads131e08.yaml | 145 +++++++++++++++++++++ > MAINTAINERS | 1 + > 2 files changed, 146 insertions(+) > create mode 100644 Documentation/devicetree/bindings/iio/adc/ti,ads131e08.yaml > > diff --git a/Documentation/devicetree/bindings/iio/adc/ti,ads131e08.yaml b/Documentation/devicetree/bindings/iio/adc/ti,ads131e08.yaml > new file mode 100644 > index 0000000..92da193 > --- /dev/null > +++ b/Documentation/devicetree/bindings/iio/adc/ti,ads131e08.yaml > @@ -0,0 +1,145 @@ > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/iio/adc/ti,ads131e08.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Texas Instruments ADS131E0x 4-, 6-, and 8-Channel ADCs Not currently supporting 6 channel variants? > + > +maintainers: > + - Tomislav Denis <tomislav.denis@xxxxxxx> > + > +description: | > + The ADS131E0x are a family of multichannel, simultaneous sampling, > + 24-bit, delta-sigma, analog-to-digital converters (ADCs) with a > + built-in programmable gain amplifier (PGA), internal reference > + and an onboard oscillator. > + The communication with ADC chip is via the SPI bus (mode 1). > + > + https://www.ti.com/lit/ds/symlink/ads131e08.pdf > + > +properties: > + compatible: > + enum: > + - ti,ads131e04 > + - ti,ads131e08 > + > + reg: > + description: | > + SPI chip select number That is entirely standard so no real need to put a description of reg for an spi device. > + maxItems: 1 > + > + spi-cpha: true > + > + clocks: > + description: | > + Device tree identifier to the clock source (2.048 MHz) > + Note: clock source is selected using CLKSEL pin > + maxItems: 1 > + > + clock-names: > + items: > + - const: adc-clk > + > + interrupts: > + description: | > + IRQ line for the ADC data ready > + maxItems: 1 > + > + vref-supply: > + description: | > + Optional external voltage reference. Has to be supplied, if > + ti,vref-sel equals 2 > + > + ti,vref-sel: > + description: | > + Select the voltage reference source > + Valid values are: > + 0: Internal reference 2.4V > + 1: Internal reference 4V > + 2: External reference source (vref-supply is required) With optional external references we normally just use their presense to indicate that they should be used. You'll still need a parameter to pick the internal reference though. > + $ref: /schemas/types.yaml#/definitions/uint32 > + enum: [0, 1, 2] > + default: 0 > + > + ti,datarate: > + description: | > + ADC data rate in kSPS > + $ref: /schemas/types.yaml#/definitions/uint32 > + enum: [1, 2, 4, 8, 16, 32, 64] > + default: 1 Why is this a devicetree element rather than runtime controllable? > + > + ti,gain: > + description: | > + The gain value for the PGA function > + $ref: /schemas/types.yaml#/definitions/uint32 > + enum: [1, 2, 4, 8, 12] > + default: 1 Isn't this per channel? Also this explanation should mention why it is a board related characteristic rather than a runtime tuneable (I'm fine with having it here, but good to add a bit of info on that to the description). > + > + ti,adc-channels: > + description: | > + List of single-ended channels muxed for this ADC > + - 4 channels, numbered from 0 to 3 for ti,ads131e04 > + - 8 channels, numbered from 0 to 7 for ti,ads131e08 > + $ref: /schemas/types.yaml#/definitions/uint32-array We've fairly recently introduced a generic adc channel binding that I'd prefer is used in drivers going forwards. See Documentation/device-tree/bindings/iio/adc.txt (or yaml if I've applied that patch before you get to this). That adds a subnode per channel and gives us an easy way to then provide per channel parameters. It's heavier weight than what you have here, but much more flexible. > + > +required: > + - compatible > + - reg > + - spi-cpha > + - clocks > + - clock-names > + - interrupts > + - ti,adc-channels > + > +allOf: > + - if: > + properties: > + compatible: > + contains: > + const: ti,ads131e04 > + > + - then: > + properties: > + ti,adc-channels: > + minItems: 1 > + maxItems: 4 > + items: > + minimum: 0 > + maximum: 3 > + > + - if: > + properties: > + compatible: > + contains: > + const: ti,ads131e08 > + > + - then: > + properties: > + ti,adc-channels: > + minItems: 1 > + maxItems: 8 > + items: > + minimum: 0 > + maximum: 7 > + > +examples: > + - | > + #include <dt-bindings/interrupt-controller/irq.h> > + > + spidev@0 { > + compatible = "ti,ads131e08"; > + reg = <0>; > + spi-max-frequency = <1000000>; > + spi-cpha; > + clocks = <&clk2048k>; > + clock-names = "adc-clk"; > + interrupt-parent = <&gpio5>; > + interrupts = <28 IRQ_TYPE_EDGE_FALLING>; > + vref-supply = <&vref_reg>; > + ti,vref-sel = <2>; > + ti,datarate = <1>; > + ti,gain = <1>; > + ti,adc-channels = <0 1 2 3 4 5 6 7>; > + }; > +... > diff --git a/MAINTAINERS b/MAINTAINERS > index 28bc5f9..0c351c7 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -17224,6 +17224,7 @@ TI ADS131E0X ADC SERIES DRIVER > M: Tomislav Denis <tomislav.denis@xxxxxxx> > L: linux-iio@xxxxxxxxxxxxxxx > S: Maintained > +F: Documentation/devicetree/bindings/iio/adc/ti,ads131e08.yaml > F: drivers/iio/adc/ti-ads131e08.c > > TI AM437X VPFE DRIVER
