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authorTomeu Vizoso <tomeu.vizoso@collabora.com>2015-03-12 15:47:56 +0100
committerThierry Reding <treding@nvidia.com>2015-05-13 15:17:09 +0200
commite34812c5bac8de641a2551b5ccb601627c10e772 (patch)
tree4fe7472a4215a42940d43063fccf769eacb8bcaa /Documentation
parent42c86547f4e5c2e81616c76ce9a2badce515c41f (diff)
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of: document new emc-timings subnode in nvidia,tegra124-car
The EMC clock needs some extra information for changing its rate. Signed-off-by: Tomeu Vizoso <tomeu.vizoso@collabora.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt42
1 files changed, 41 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt b/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt
index c6620bc96703..c3891cece73f 100644
--- a/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt
+++ b/Documentation/devicetree/bindings/clock/nvidia,tegra124-car.txt
@@ -21,10 +21,31 @@ 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>;
@@ -62,4 +83,23 @@ 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";
+ };
+ };
+ };
};