On Fri, Nov 15, 2024 at 02:18:46PM -0600, David Lechner wrote: > The AXI SPI Engine has support for hardware offloading capabilities. > This includes a connection to a DMA controller for streaming RX data > and a trigger input for starting execution of the SPI message programmed > in the offload. > > Each SPI Engine may have up to 1 offload. The spec actually says that > it could support up to 32, so we are using an index number in the > dma-names (e.g. offload0-rx) to allow for this possibility in the > future. > > Signed-off-by: David Lechner <dlechner@xxxxxxxxxxxx> > --- > > v5 changes: > * Also document offload0-tx DMA names since the hardware can support > that now. > * Limit the number of offloads to 1 for now since it would require > significant hardware changes to actually support more than that. > > v4 changes: > * Dropped #spi-offload-cells property. > * Changed subject line. > > v3 changes: > * Added #spi-offload-cells property. > * Added properties for triggers and RX data stream connected to DMA. > > v2 changes: > * This is basically a new patch. It partially replaces "dt-bindings: > iio: offload: add binding for PWM/DMA triggered buffer". > * The controller no longer has an offloads object node and the > spi-offloads property is now a standard SPI peripheral property. > --- > .../bindings/spi/adi,axi-spi-engine.yaml | 24 ++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml b/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml > index d48faa42d025..d703b47eb498 100644 > --- a/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml > +++ b/Documentation/devicetree/bindings/spi/adi,axi-spi-engine.yaml > @@ -41,6 +41,26 @@ properties: > - const: s_axi_aclk > - const: spi_clk > > + trigger-sources: > + description: > + An array of trigger source phandles for offload instances. The index in > + the array corresponds to the offload instance number. How can you have an index when you only allow 1 entry (other than 0 of course)? > + $ref: /schemas/types.yaml#/definitions/phandle-array With my other comments implemented, this should be dropped. > + maxItems: 1 > + > + dmas: > + description: > + DMA channels connected to the input or output stream interface of an > + offload instance. > + minItems: 1 > + maxItems: 2 > + > + dma-names: > + items: > + pattern: "^offload0-[tr]x$" Do you expect an offload1 or something? > + minItems: 1 > + maxItems: 2 > + > required: > - compatible > - reg > @@ -59,6 +79,10 @@ examples: > clocks = <&clkc 15>, <&clkc 15>; > clock-names = "s_axi_aclk", "spi_clk"; > > + trigger-sources = <&trigger_clock>; > + dmas = <&dma 0>; > + dma-names = "offload0-rx"; > + > #address-cells = <1>; > #size-cells = <0>; > > > -- > 2.43.0 >
