On 27/09/17 02:57, Dmitry Osipenko wrote: > On 26.09.2017 17:50, Jon Hunter wrote: >> >> On 26/09/17 00:22, Dmitry Osipenko wrote: >>> Document DT bindings for NVIDIA Tegra AHB DMA controller that presents >>> on Tegra20/30 SoC's. >>> >>> Signed-off-by: Dmitry Osipenko <dig...@gmail.com> >>> --- >>> .../bindings/dma/nvidia,tegra20-ahbdma.txt | 23 >>> ++++++++++++++++++++++ >>> 1 file changed, 23 insertions(+) >>> create mode 100644 >>> Documentation/devicetree/bindings/dma/nvidia,tegra20-ahbdma.txt >>> >>> diff --git >>> a/Documentation/devicetree/bindings/dma/nvidia,tegra20-ahbdma.txt >>> b/Documentation/devicetree/bindings/dma/nvidia,tegra20-ahbdma.txt >>> new file mode 100644 >>> index 000000000000..2af9aa76ae11 >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/dma/nvidia,tegra20-ahbdma.txt >>> @@ -0,0 +1,23 @@ >>> +* NVIDIA Tegra AHB DMA controller >>> + >>> +Required properties: >>> +- compatible: Must be "nvidia,tegra20-ahbdma" >>> +- reg: Should contain registers base address and length. >>> +- interrupts: Should contain one entry, DMA controller interrupt. >>> +- clocks: Should contain one entry, DMA controller clock. >>> +- resets : Should contain one entry, DMA controller reset. >>> +- #dma-cells: Should be <1>. The cell represents DMA request select >>> value >>> + for the peripheral. For more details consult the Tegra TRM's >>> + documentation, in particular AHB DMA channel control register >>> + REQ_SEL field. >> >> What about the TRIG_SEL field? Do we need to handle this here as well? >> > > Actually, DMA transfer trigger isn't related a hardware description. It's up > to > software to decide what trigger to select. So it shouldn't be in the binding.
I think it could be, if say a board wanted a GPIO to trigger a transfer. > And I think the same applies to requester... any objections? Well, the REQ_SEL should definitely be in the binding. Laxman, Stephen, what are your thoughts on the TRIG_SEL field? Looks like we never bothered with it for the APB DMA and so maybe no ones uses this. Cheers Jon -- nvpublic
