[RFC v2: PATCH 1/2] dt-bindings: Document the hi3660 reset bindings

Am Donnerstag, den 24.11.2016, 17:40 +0800 schrieb zhangfei:

On 2016?11?24? 17:26, Philipp Zabel wrote:

quoted

Am Mittwoch, den 23.11.2016, 16:07 +0800 schrieb Zhangfei Gao:

quoted

Add DT bindings documentation for hi3660 SoC reset controller.

Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org>
---
  .../bindings/reset/hisilicon,hi3660-reset.txt      | 51 ++++++++++++++++++++++
  1 file changed, 51 insertions(+)
  create mode 100644 Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt

diff --git a/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt
new file mode 100644
index 0000000..250daf2
--- /dev/null
+++ b/Documentation/devicetree/bindings/reset/hisilicon,hi3660-reset.txt

@@ -0,0 +1,51 @@
+Hisilicon System Reset Controller
+======================================
+
+Please also refer to reset.txt in this directory for common reset
+controller binding usage.
+
+The reset controller registers are part of the system-ctl block on
+hi3660 SoC.
+
+Required properties:
+- compatible: should be
+		 "hisilicon,hi3660-reset"
+- #reset-cells: 1, see below
+- hisi,rst-syscon: phandle of the reset's syscon.
+- hisi,reset-bits: Contains the reset control register information
+		  Should contain 2 cells for each reset exposed to
+		  consumers, defined as:
+			Cell #1 : offset from the syscon register base
+			Cell #2 : bits position of the control register
+
+Example:
+	iomcu: iomcu at ffd7e000 {
+		compatible = "hisilicon,hi3660-iomcu", "syscon";
+		reg = <0x0 0xffd7e000 0x0 0x1000>;
+	};
+
+	iomcu_rst: iomcu_rst_controller {

This should be
	iomcu_rst: reset-controller {

quoted

+		compatible = "hisilicon,hi3660-reset";
+		#reset-cells = <1>;
+		hisi,rst-syscon = <&iomcu>;
+		hisi,reset-bits = <0x20 0x8		/* 0: i2c0 */
+				   0x20 0x10		/* 1: i2c1 */
+				   0x20 0x20		/* 2: i2c2 */
+				   0x20 0x8000000>;	/* 3: i2c6 */
+	};

The reset lines are controlled through iomcu bits, is there a reason not
to put the iomcu_rst node inside the iomcu node? That way the
hisi,rst-syscon property could be removed and the syscon could be
retrieved via the reset-controller parent node.

iomcu is common registers, controls clock and reset, etc.
So we use syscon, without mapping the registers everywhere.
It is common case in hisilicon, same in hi6220.

Also the #clock-cells and #reset-cells can not be put in the same node,
if they are both using probe, since reset_probe will not be called.

So we use hisi,rst-syscon as a general solution.

What I meant is this:

	iomcu: iomcu at ffd7e000 {
		compatible = "hisilicon,hi3660-iomcu", "syscon", "simple-mfd";
		reg = <0x0 0xffd7e000 0x0 0x1000>;

		iomcu_rst: reset-controller {
			compatible = "hisilicon,hi3660-reset";
			#reset-cells = <1>;
			hisi,reset-bits = <0x20 0x8		/* 0: i2c0 */
					   0x20 0x10		/* 1: i2c1 */
					   0x20 0x20		/* 2: i2c2 */
					   0x20 0x8000000>;	/* 3: i2c6 */
		};
	};

regards
Philipp