On 2016-10-10 21:54, Rob Herring wrote:

On Fri, Oct 07, 2016 at 06:18:32PM +0300, Pantelis Antoniou wrote:

quoted

From: Georgi Vlaev <redacted>

Add binding document for the i2c driver of SAM FPGA.

Signed-off-by: Georgi Vlaev <redacted>
[Ported from Juniper kernel]
Signed-off-by: Pantelis Antoniou <redacted>
---
 .../devicetree/bindings/i2c/i2c-sam-mux.txt        | 20 ++++++++++
 Documentation/devicetree/bindings/i2c/i2c-sam.txt  | 44 ++++++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sam-mux.txt
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-sam.txt

diff --git a/Documentation/devicetree/bindings/i2c/i2c-sam-mux.txt b/Documentation/devicetree/bindings/i2c/i2c-sam-mux.txt
new file mode 100644
index 0000000..10ddffa
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-sam-mux.txt

@@ -0,0 +1,20 @@
+Juniper's SAM FPGA I2C accelerator mux
+
+The SAM FPGA I2C mux is present only on Juniper SAM FPGA PTX series
+of routers.
+
+The definition of the i2c sam bus is located in the i2c-sam.txt document.
+
+Required properties:
+- compatible: should be "jnx,i2c-sam-mux".
+- reg: master number and mux number.

This is not how i2c muxes are done.

quoted

+
+Optional properties:
+- speed: If present must be either 100000 or 400000. No other values supported.
+
+Examples:
+
+pe1i2c: i2c-sam-mux@1,0 {

i2c-mux@...

quoted

+	compatible = "jnx,i2c-sam-mux";
+	reg = <1 0>;
+};

diff --git a/Documentation/devicetree/bindings/i2c/i2c-sam.txt b/Documentation/devicetree/bindings/i2c/i2c-sam.txt
new file mode 100644
index 0000000..4830b48
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/i2c-sam.txt

@@ -0,0 +1,44 @@
+Juniper's SAM FPGA I2C accelerator
+
+The SAM FPGA accelerator is used to connect the large number of
+I2C muxes that are present on Juniper PTX series of routers.
+While it's an i2c bus, no other devices are located besides
+i2c-sam-mux devices.
+
+The definition of the i2c sam mux is located in the i2c-sam-mux.txt document.
+
+Required properties:
+- compatible: should be "jnx,i2c-sam".
+- #address-cells: should be 2.
+- #size-cells: should be 0.
+- mux-channels: number of mux channels present

What is this needed for?

quoted

+
+Optional properties:
+- reg: offset and length of the register set for the device are optional since
+  typically the register range is provided by the parent SAM MFD device.
+- master-offset: Offset of where the master register memory starts.
+  Default value is 0x8000.

Make this required.

quoted

+- reverse-fill: Fill the start entries of transactions in reverse order

Needs a better explanation.

quoted

+- priority-tables: Use the pre-programmed priority tables in the FPGA

What does not present mean?

quoted

+- i2c-options: list of options to be written to the option field in the
+  FPGA controlling things like SCL push-pull drives, hold-times, etc.

quoted

+- bus-range: start of bus master range and number of masters.

Needs a better explanation.

quoted

+
+Examples:
+
+i2c-sam {
+	compatible = "jnx,i2c-sam";
+	mux-channels = <2>;
+	#size-cells = <0>;
+	#address-cells = <2>;
+
+	/* PE0 */ pe0i2c: i2c-sam-mux@0,0 {

i2c-mux@...

Hmm, I actually think i2c@... is the usual naming for i2c-mux children.

Cheers,
Peter

quoted

+		compatible = "jnx,i2c-sam-mux";
+		reg = <0 0>;
+	};
+
+	/* PE1 */ pe1i2c: i2c-sam-mux@1,0 {
+		compatible = "jnx,i2c-sam-mux";
+		reg = <1 0>;
+	};
+};
-- 
1.9.1

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