On 27/09/17 13:12, Dmitry Osipenko wrote: > On 27.09.2017 11:34, Jon Hunter wrote: >> >> 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 <digetx@xxxxxxxxx> >>>>> --- >>>>> .../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. >> > > GPIO isn't a very good example, there is no "GPIO" trigger. To me all triggers > are software-defined, so that software could create transfer chains. TRM shows the following in the APBDMA_TRIG_REG_0 ... "XRQ_A: XRQ.A (GPIOA) (Hardware initiated DMA request)" Jon -- nvpublic -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
