On Mon, Jul 18, 2016 at 11:16 AM, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: > On 07/16/2016 03:07 PM, Rob Herring wrote: >> >> On Thu, Jul 07, 2016 at 01:37:11PM -0600, Stephen Warren wrote: >>> >>> From: Stephen Warren <swarren@xxxxxxxxxx> >>> >>> In Tegra186, the BPMP (Boot and Power Management Processor) owns certain >>> HW devices, such as the I2C controller for the power management I2C bus. >>> Software running on other CPUs must perform IPC to the BPMP in order to >>> execute transactions on that I2C bus. This binding describes an I2C bus >>> that is accessed in such a fashion. >>> >>> Signed-off-by: Stephen Warren <swarren@xxxxxxxxxx> >>> --- >>> .../bindings/i2c/nvidia,tegra186-bpmp-i2c.txt | 35 >>> ++++++++++++++++++++++ >>> 1 file changed, 35 insertions(+) >>> create mode 100644 >>> Documentation/devicetree/bindings/i2c/nvidia,tegra186-bpmp-i2c.txt >>> >>> diff --git >>> a/Documentation/devicetree/bindings/i2c/nvidia,tegra186-bpmp-i2c.txt >>> b/Documentation/devicetree/bindings/i2c/nvidia,tegra186-bpmp-i2c.txt >>> new file mode 100644 >>> index 000000000000..eb9f70723ab7 >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/i2c/nvidia,tegra186-bpmp-i2c.txt >>> @@ -0,0 +1,35 @@ >>> +NVIDIA Tegra186 BPMP I2C controller >>> + >>> +In Tegra186, the BPMP (Boot and Power Management Processor) owns certain >>> HW >>> +devices, such as the I2C controller for the power management I2C bus. >>> Software >>> +running on other CPUs must perform IPC to the BPMP in order to execute >>> +transactions on that I2C bus. This binding describes an I2C bus that is >>> +accessed in such a fashion. >>> + >>> +Required properties: >>> +- compatible: >>> + Array of strings. >>> + One of: >>> + - "nvidia,tegra186-bpmp-i2c". >>> +- address-cells: Address cells for I2C device address. >>> + Single-cell integer. >>> + Must be <1>. >>> +- size-cells: >>> + Single-cell integer. >>> + Must be <0>. >>> +- nvidia,bpmp: >>> + The phandle to the BPMP device. >> >> >> Any reason to not make this a sub-node of the BPMP device? > > > That would be possible too. > > My thought process was along the lines of: The system has an I2C bus, which > deserves a DT node. That fact seemed more important than the access > mechanism; the fact it's accessed via BPMP rather than direct register > access felt a bit more like an implementation detail. Still, I suppose we > could flip it around and store the node underneath the BPMP if you want; let > me know. I prefer to utilize the hierarchy unless there are reasons it can't be which doesn't seem to be the case here. Rob -- 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
