Hi Rob,
Thank you for your comments.
On 5/19/2016 07:05, Rob Herring wrote:
On Wed, May 18, 2016 at 03:46:29PM +0800, Songjun Wu wrote:
DT binding documentation for ISC driver.
Signed-off-by: Songjun Wu <songjun.wu@xxxxxxxxx>
---
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 | 100 +++++++++++++++++++++
1 file changed, 100 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..9e65395
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/atmel-isc.txt
@@ -0,0 +1,100 @@
+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 ISC;
+- 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.
+- clk-in-isc
+ ISC internal clock node, it includes two clock nodes,
+ isc-ispck and isc-mck.
And you need to describe each of these nodes and the properties they
have. But more on this below...
Should I move the description of clock node below to here?
+- atmel,sensor-preferred
+ ISC may convert the raw format to the specified format when the sensor
+ outputs the raw format, and the sensor may output the specified format
+ directly. If sensor is preferred to output the specified format
+ directly, the value should be 1 (1-preferred, 0-not).
+ The default value is 1.
I don't think this belongs in DT. It sounds more like a configuration
and userspace decision. It is still not clear what you mean by
"specified format".
Accept, I will remove this.
+
+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.
+
+Required properties for the ISC internal clocks:
+- #address-cells
+ should be 1 (reg is used to encode clk id).
+- #size-cells
+ should be 0 (reg is used to encode clk id).
+- name
+ device tree node describing a ISC internal clock.
+ * #clock-cells: from common clock binding; should be set to 0.
+ * reg: clock id, there are two values,
+ <0> is ISP clock, <1> is master clock.
+ * clocks: shall be the isc internal clock source phandles.
+ e.g. clocks = <&isc_clk>, <&iscck>, <&isc_gclk>;
+
+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";
+ atmel,sensor-preferred = <1>;
+
+ port {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ isc_0: endpoint {
+ remote-endpoint = <&ov7740_0>;
+ hsync-active = <1>;
+ vsync-active = <0>;
+ pclk-sample = <1>;
+ };
+ };
+
+ clk-in-isc {
Is this really separate from the rest of the isc block. It would be
much more simple to define all the input clocks at the parent and then
reference these 2 clocks with <&isc 0> and <&isc 1>.
Yes, it's separate from the rest of isc block.
It will register two clocks, one is used in ISC internal processor, the
other will provide the clock to the sensor outside.
I think it's better that the parent clock is included in node
'clk-in-isc' node. I will try to optimize this node.
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ isc_ispck: isc-ispck@0 {
These would need a compatible string otherwise.
+ #clock-cells = <0>;
+ reg = <0>;
Are 0 and 1 meaningful in terms of the hardware description?
Yes, It's meaningful.
The register field is different, 0 and 1 can distinguish the different
clock.
+ clocks = <&isc_clk>, <&iscck>;
+ };
+
+ isc_mck: isc-mck@1 {
+ #clock-cells = <0>;
+ reg = <1>;
+ clocks = <&isc_clk>, <&iscck>, <&isc_gclk>;
+ };
+ };
+};
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