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Subject[RFC PATCH v5 1/6] dt-bindings: exynos-bus: Add documentation for interconnect properties
Date
Add documentation for new optional properties in the exynos bus nodes:
samsung,interconnect-parent, #interconnect-cells.
These properties allow to specify the SoC interconnect structure which
then allows the interconnect consumer devices to request specific
bandwidth requirements.

Signed-off-by: Artur Świgoń <a.swigon@samsung.com>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
---
Changes for v5:
- exynos,interconnect-parent-node renamed to samsung,interconnect-parent
---
Documentation/devicetree/bindings/devfreq/exynos-bus.txt | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
index e71f752..e0d2daa 100644
--- a/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
+++ b/Documentation/devicetree/bindings/devfreq/exynos-bus.txt
@@ -51,6 +51,11 @@ Optional properties only for parent bus device:
- exynos,saturation-ratio: the percentage value which is used to calibrate
the performance count against total cycle count.

+Optional properties for interconnect functionality (QoS frequency constraints):
+- samsung,interconnect-parent: phandle to the parent interconnect node; for
+ passive devices should point to same node as the exynos,parent-bus property.
+- #interconnect-cells: should be 0
+
Detailed correlation between sub-blocks and power line according to Exynos SoC:
- In case of Exynos3250, there are two power line as following:
VDD_MIF |--- DMC
@@ -185,8 +190,9 @@ Example1:
----------------------------------------------------------

Example2 :
- The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
- is listed below:
+ The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi is
+ listed below. An interconnect path "bus_lcd0 -- bus_leftbus -- bus_dmc"
+ is defined for demonstration purposes.

bus_dmc: bus_dmc {
compatible = "samsung,exynos-bus";
@@ -376,12 +382,15 @@ Example2 :
&bus_dmc {
devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
vdd-supply = <&buck1_reg>; /* VDD_MIF */
+ #interconnect-cells = <0>;
status = "okay";
};

&bus_leftbus {
devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
vdd-supply = <&buck3_reg>;
+ samsung,interconnect-parent = <&bus_dmc>;
+ #interconnect-cells = <0>;
status = "okay";
};

@@ -392,6 +401,8 @@ Example2 :

&bus_lcd0 {
devfreq = <&bus_leftbus>;
+ samsung,interconnect-parent = <&bus_leftbus>;
+ #interconnect-cells = <0>;
status = "okay";
};

--
2.7.4
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