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.
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