On 05/05/16 17:48, Rob Herring wrote: > On Thu, May 5, 2016 at 9:39 AM, Jon Hunter <jonathanh@xxxxxxxxxx> wrote: >> >> On 03/05/16 19:22, Rob Herring wrote: >>> On Fri, Apr 29, 2016 at 02:53:45PM +0100, Jon Hunter wrote: >>>> Add binding documentation for the Tegra ACONNECT bus that is part of the >>>> Audio Processing Engine (APE) on Tegra210. The ACONNECT bus is used to >>>> access devices within the APE subsystem. The APE is located in a >>>> separate power domain and so accesses made to the ACONNECT require the >>>> power domain to be enabled as well as some platform specific clocks. >>>> >>>> Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx> >>>> --- >>>> .../bindings/bus/nvidia,tegra210-aconnect.txt | 45 ++++++++++++++++++++++ >>>> 1 file changed, 45 insertions(+) >>>> create mode 100644 Documentation/devicetree/bindings/bus/nvidia,tegra210-aconnect.txt >>>> >>>> diff --git a/Documentation/devicetree/bindings/bus/nvidia,tegra210-aconnect.txt b/Documentation/devicetree/bindings/bus/nvidia,tegra210-aconnect.txt >>>> new file mode 100644 >>>> index 000000000000..e5e915f8fca7 >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/bus/nvidia,tegra210-aconnect.txt >>>> @@ -0,0 +1,45 @@ >>>> +NVIDIA Tegra ACONNECT Bus >>>> + >>>> +The Tegra ACONNECT bus is an AXI switch which is used to connnect various >>>> +components inside the Audio Processing Engine (APE). All CPU accesses to >>>> +the APE subsystem go through the ACONNECT via an APB to AXI wrapper. >>>> + >>>> +Required properties: >>>> +- compatible: Must be "nvidia,tegra210-aconnect". >>>> +- clocks: Must contain the entries for the APE clock (TEGRA210_CLK_APE), >>>> + and APE interface clock (TEGRA210_CLK_APB2APE). >>>> +- clock-names: Must contain the names "ape" and "apb2ape" for the corresponding >>>> + 'clocks' entries. >>>> +- power-domains: Must contain a phandle that points to the audio powergate >>>> + (namely 'aud') for Tegra210. >>>> +- #address-cells: The number of cells used to represent physical base addresses >>>> + in the host1x address space. Should be 2. >>>> +- #size-cells: The number of cells used to represent the size of an address >>>> + range in the host1x address space. Should be 2. >>> >>> Do you really need >4GB of child addresses? >> >> Sounds rather silly when you put it like that. No, its not needed. I >> will fix that. >> >>>> +- ranges: 1:1 mapping of the aconnect address space to the CPU address space. >>> >>> Why 1:1 for 256KB of address space? >> >> No good reason. I have looking at what we did for host1x and ahub which >> also have a ranges property and use a 1:1 mapping. For ahub this makes >> sense because it is more of a cross-bar/switch. The aconnect bus is also >> a switch and thought may be that is the easiest thing to do. What is >> recommended here? > > Use of non-empty ranges is preferred though there is not much benefit > if the parent and child sizes are the same. However, it does also > limit what is a valid address for those child nodes. Thanks. Yes if I change the child sizes to be 1, then I guess I need to have a non-empty ranges anyway. Cheers Jon -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
