On Thu, 2 Jun 2016 18:16:09 -0500
Rob Herring [off-list ref] wrote:

On Tue, May 31, 2016 at 02:58:23PM +0800, Songjun Wu wrote:

quoted

DT binding documentation for ISC driver.

Signed-off-by: Songjun Wu <redacted>
---

Changes in v3:
- Remove the 'atmel,sensor-preferred'.
- Modify the isc clock node according to the Rob's remarks.

Changes in v2:
- Remove the unit address of the endpoint.
- Add the unit address to the clock node.
- Avoid using underscores in node names.
- Drop the "0x" in the unit address of the i2c node.
- Modify the description of 'atmel,sensor-preferred'.
- Add the description for the ISC internal clock.

 .../devicetree/bindings/media/atmel-isc.txt        | 88 ++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/atmel-isc.txt

diff --git a/Documentation/devicetree/bindings/media/atmel-isc.txt b/Documentation/devicetree/bindings/media/atmel-isc.txt
new file mode 100644
index 0000000..2ae1d60
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/atmel-isc.txt

@@ -0,0 +1,88 @@
+Atmel Image Sensor Controller (ISC)
+----------------------------------------------
+
+Required properties for ISC:
+- compatible
+	Must be "atmel,sama5d2-isc"
+- reg
+	Physical base address and length of the registers set for the device;
+- interrupts
+	Should contain IRQ line for the ISI;
+- clocks
+	List of clock specifiers, corresponding to entries in
+	the clock-names property;
+	Please refer to clock-bindings.txt.
+- clock-names
+	Required elements: "hclock", "ispck".
+- pinctrl-names, pinctrl-0
+	Please refer to pinctrl-bindings.txt.
+- isc-ispck
+	The clock for the ISC digital pipeline.
+	- compatible
+		Must be "atmel,sama5d2-isc-ispck".
+	- clock-cells
+		From common clock binding; should be set to 0.
+	- clocks
+		The clock source phandles.
+- isc-mck
+	The clock for the image sensor.
+	- compatible
+		Must be "atmel,sama5d2-isc-mck".
+	- clock-cells
+		From common clock binding; should be set to 0.
+	- clocks
+		The clock source phandles.
+
+ISC supports a single port node with parallel bus. It should contain one
+'port' child node with child 'endpoint' node. Please refer to the bindings
+defined in Documentation/devicetree/bindings/media/video-interfaces.txt.
+
+Example:
+isc: isc@f0008000 {
+	compatible = "atmel,sama5d2-isc";
+	reg = <0xf0008000 0x4000>;
+	interrupts = <46 IRQ_TYPE_LEVEL_HIGH 5>;
+	clocks = <&isc_clk>, <&isc_ispck>;
+	clock-names = "hclock", "ispck";
+
+	port {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		isc_0: endpoint {
+			remote-endpoint = <&ov7740_0>;
+			hsync-active = <1>;
+			vsync-active = <0>;
+			pclk-sample = <1>;
+		};
+	};
+
+	isc_ispck: isc-ispck@0 {  

Drop the unit-address. You should only have one if you have a reg 
property.

quoted

+		compatible = "atmel,sama5d2-isc-ispck";
+		#clock-cells = <0>;
+		clocks = <&isc_clk>, <&iscck>;
+	};
+
+	isc_mck: isc-mck@1 {  

ditto.

I still think these should be implied by atmel,sama5d2-isc and not in 
DT. The fact that you don't have any registers for them pretty much 
indicates that. It is also strange that isc-ispck is used by isc. If 
that is the only user, there is certainly no need to put it in DT.

I had a look at the block diagram, and it seems you are partially right.
The only clock that is really exported by the ISC is isc_mck (isc_pck is
not).
So I'd suggest dropping these clk sub-nodes, putting the #clock-cells,
and clock-names properties in the isc node, and then referencing the
isc node in you i2c device.

isc: isc@f0008000 {
	compatible = "atmel,sama5d2-isc";
	reg = <0xf0008000 0x4000>;
	interrupts = <46 IRQ_TYPE_LEVEL_HIGH 5>;
	clocks = <&isc_clk>, <&isc_ispck>;
	clock-names = "hclock", "ispck";
	#clock-cells = <0>;
	clock-output-names = "isc-mck";
};

i2c1: i2c@fc028000 {
	/* ... */
	ov7740: camera@21 {
		/* ... */
		clocks = <&isc>;
		clock-names = "xvclk";
	}
};

If I'm wrong and the ISC IP is really exposing several clks, you just
have to change #clock-cells to 1, and use clocks = <&isc X>; in the i2c
device node.

Rob, Songjun, would you agree on this representation?

quoted

+		compatible = "atmel,sama5d2-isc-mck";
+		#clock-cells = <0>;
+		clocks = <&isc_clk>, <&iscck>, <&isc_gclk>;
+	};
+};
+
+i2c1: i2c@fc028000 {
+	ov7740: camera@21 {
+	compatible = "ovti,ov7740";
+	reg = <0x21>;
+
+	clocks = <&isc_mck>;
+	clock-names = "xvclk";
+	assigned-clocks = <&isc_mck>;
+	assigned-clock-rates = <24000000>;
+
+	port {
+		ov7740_0: endpoint {
+			remote-endpoint = <&isc_0>;
+		};
+	};
+};
-- 
2.7.4
  

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