On Wed, Jan 10, 2024 at 01:49:45PM -0600, David Lechner wrote: > The ADI AXI SPI Engine driver supports offloading SPI transfers to > hardware. This is essentially a feature that allows recording an > arbitrary sequence of SPI transfers and then playing them back with > no CPU intervention via a hardware trigger. > > This adds the bindings for this feature. Each SPI Engine instance > can have from 0 to 32 offload instances. Each offload instance has a > trigger input and a data stream output. As an example, this could be > used with an ADC SPI peripheral. In this case the trigger is connected > to a PWM/clock to determine the sampling rate for the ADC and the output > stream is connected to a DMA channel to pipe the sample data to memory. > > SPI peripherals act as consumers of the offload instances. Typically, > one SPI peripheral will be connected to one offload instance. But to > make the bindings future-proof, the property is an array. Is there some sort of arbitration between multiple offload engines on the same chip select? If not, I don't see how it would work. I think this whole thing could be simplified down to just 3 SPI controller properties: pwms, dmas, and adi,offload-cs-map. Each property is has entries equal the number of offload engines. The last one maps an offload engine to a SPI chip-select. > > Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx> > --- > .../spi/adi,axi-spi-engine-peripheral-props.yaml | 24 +++++++++++ > .../bindings/spi/adi,axi-spi-engine.yaml | 49 +++++++++++++++++++++- > .../bindings/spi/spi-peripheral-props.yaml | 1 + > 3 files changed, 73 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/spi/adi,axi-spi-engine-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/adi,axi-spi-engine-peripheral-props.yaml > new file mode 100644 > index 000000000000..19b685fc3b39 > --- /dev/null > +++ b/Documentation/devicetree/bindings/spi/adi,axi-spi-engine-peripheral-props.yaml > @@ -0,0 +1,24 @@ > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) > +%YAML 1.2 > +--- > +$id: http://devicetree.org/schemas/spi/adi,axi-spi-engine-peripheral-props.yaml# > +$schema: http://devicetree.org/meta-schemas/core.yaml# > + > +title: Peripheral properties for Analog Devices AXI SPI Engine Controller > + > +maintainers: > + - Michael Hennerich <Michael.Hennerich@xxxxxxxxxx> > + - Nuno Sá <nuno.sa@xxxxxxxxxx> > + > +properties: > + adi,offloads: > + description: > + List of AXI SPI Engine offload instances assigned to this peripheral. > + $ref: /schemas/types.yaml#/definitions/uint32-array > + maxItems: 32 > + items: > + items: > + - minimum: 0 > + maximum: 31 This defines a matrix. You want: minItems: 1 maxItems: 32 items: maximum: 31 (0 is already the min). > + > +additionalProperties: true > diff --git a/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml b/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml > index d48faa42d025..69f3261bab47 100644 > --- a/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml > +++ b/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml > @@ -21,6 +21,23 @@ maintainers: > allOf: > - $ref: /schemas/spi/spi-controller.yaml# > > +$defs: > + offload: > + description: > + Describes the connections of the trigger input and the data output stream > + of one or more offload instances. > + > + properties: > + reg: > + description: > + Index of the offload instance. > + items: > + - minimum: 0 > + maximum: 31 > + > + required: > + - reg > + > properties: > compatible: > const: adi,axi-spi-engine-1.00.a > @@ -41,6 +58,22 @@ properties: > - const: s_axi_aclk > - const: spi_clk > > + offloads: > + type: object > + description: Zero or more offloads supported by the controller. > + > + properties: > + "#address-cells": > + const: 1 > + > + "#size-cells": > + const: 0 > + > + patternProperties: > + "^offload@[0-8a-f]+$": > + type: object > + $ref: '#/$defs/offload' > + > required: > - compatible > - reg > @@ -62,5 +95,19 @@ examples: > #address-cells = <1>; > #size-cells = <0>; > > - /* SPI devices */ > + offloads { > + #address-cells = <1>; > + #size-cells = <0>; > + > + offload@0 { > + compatible = "adi,example-offload"; No fake examples please. This should give you a warning. > + reg = <0>; > + }; > + }; > + > + adc@0 { > + compatible = "adi,example-adc"; > + reg = <0>; > + adi,offloads = <0>; > + }; > }; > diff --git a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml > index 1c8e71c18234..7beb5a3798a5 100644 > --- a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml > +++ b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml > @@ -132,6 +132,7 @@ properties: > > # The controller specific properties go here. > allOf: > + - $ref: adi,axi-spi-engine-peripheral-props.yaml# > - $ref: arm,pl022-peripheral-props.yaml# > - $ref: cdns,qspi-nor-peripheral-props.yaml# > - $ref: samsung,spi-peripheral-props.yaml# > > -- > 2.43.0 >
