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[v5,04/14] of: document new emc-timings subnode in nvidia, tegra124-car

Message ID 1416312860-4446-5-git-send-email-tomeu.vizoso@collabora.com
State Accepted, archived
Commit e34812c5bac8de641a2551b5ccb601627c10e772
Headers show

Commit Message

Tomeu Vizoso Nov. 18, 2014, 12:13 p.m. UTC
The EMC clock needs some extra information for changing its rate.

Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>

---

v5:	* Remove constraint on the unit-address of the timings and timing subnodes

v4:	* Remove comma from unit-address of CAR node in the example
	* Simplify reg property value in the example
---
 .../bindings/clock/nvidia,tegra124-car.txt         | 42 +++++++++++++++++++++-
 1 file changed, 41 insertions(+), 1 deletion(-)
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Patch

diff --git a/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt b/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt
index ded5d62..2197ffd 100644
--- a/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt
+++ b/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt
@@ -19,10 +19,31 @@  Required properties :
   In clock consumers, this cell represents the bit number in the CAR's
   array of CLK_RST_CONTROLLER_RST_DEVICES_* registers.
 
+The node should contain a "emc-timings" subnode for each supported RAM type (see
+field RAM_CODE in register PMC_STRAPPING_OPT_A).
+
+Required properties for "emc-timings" nodes :
+- nvidia,ram-code : Should contain the value of RAM_CODE this timing set
+  is used for.
+
+Each "emc-timings" node should contain a "timing" subnode for every supported
+EMC clock rate.
+
+Required properties for "timing" nodes :
+- clock-frequency : Should contain the memory clock rate to which this timing
+relates.
+- nvidia,parent-clock-frequency : Should contain the rate at which the current
+parent of the EMC clock should be running at this timing.
+- clocks : Must contain an entry for each entry in clock-names.
+  See ../clocks/clock-bindings.txt for details.
+- clock-names : Must include the following entries:
+  - emc-parent : the clock that should be the parent of the EMC clock at this
+timing.
+
 Example SoC include file:
 
 / {
-	tegra_car: clock {
+	tegra_car: clock@60006000 {
 		compatible = "nvidia,tegra124-car";
 		reg = <0x60006000 0x1000>;
 		#clock-cells = <1>;
@@ -60,4 +81,23 @@  Example board file:
 	&tegra_car {
 		clocks = <&clk_32k> <&osc>;
 	};
+
+	clock@60006000 {
+		emc-timings-3 {
+			nvidia,ram-code = <3>;
+
+			timing-12750000 {
+				clock-frequency = <12750000>;
+				nvidia,parent-clock-frequency = <408000000>;
+				clocks = <&tegra_car TEGRA124_CLK_PLL_P>;
+				clock-names = "emc-parent";
+			};
+			timing-20400000 {
+				clock-frequency = <20400000>;
+				nvidia,parent-clock-frequency = <408000000>;
+				clocks = <&tegra_car TEGRA124_CLK_PLL_P>;
+				clock-names = "emc-parent";
+			};
+		};
+	};
 };