clk: tegra: Add Tegra210 device tree binding

Add a header file that defines the clock numbers for Tegra210. It is
meant to be included by device trees so that they can refer to the
clocks by symbolic name instead of numeric value.

Also add the device tree binding documentation which is largely the
same as for earlier generations of Tegra.

Extracted from a larger patch by Rhyland Klein <rklein@nvidia.com>.

Signed-off-by: Thierry Reding <treding@nvidia.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/clock/nvidia,tegra210-car.txt b/Documentation/devicetree/bindings/clock/nvidia,tegra210-car.txt
new file mode 100644
index 000000000000..26f237f641b7
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/nvidia,tegra210-car.txt
@@ -0,0 +1,56 @@
+NVIDIA Tegra210 Clock And Reset Controller
+
+This binding uses the common clock binding:
+Documentation/devicetree/bindings/clock/clock-bindings.txt
+
+The CAR (Clock And Reset) Controller on Tegra is the HW module responsible
+for muxing and gating Tegra's clocks, and setting their rates.
+
+Required properties :
+- compatible : Should be "nvidia,tegra210-car"
+- reg : Should contain CAR registers location and length
+- clocks : Should contain phandle and clock specifiers for two clocks:
+  the 32 KHz "32k_in".
+- #clock-cells : Should be 1.
+  In clock consumers, this cell represents the clock ID exposed by the
+  CAR. The assignments may be found in header file
+  <dt-bindings/clock/tegra210-car.h>.
+- #reset-cells : Should be 1.
+  In clock consumers, this cell represents the bit number in the CAR's
+  array of CLK_RST_CONTROLLER_RST_DEVICES_* registers.
+
+Example SoC include file:
+
+/ {
+	tegra_car: clock {
+		compatible = "nvidia,tegra210-car";
+		reg = <0x60006000 0x1000>;
+		#clock-cells = <1>;
+		#reset-cells = <1>;
+	};
+
+	usb@c5004000 {
+		clocks = <&tegra_car TEGRA210_CLK_USB2>;
+	};
+};
+
+Example board file:
+
+/ {
+	clocks {
+		compatible = "simple-bus";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		clk_32k: clock@1 {
+			compatible = "fixed-clock";
+			reg = <1>;
+			#clock-cells = <0>;
+			clock-frequency = <32768>;
+		};
+	};
+
+	&tegra_car {
+		clocks = <&clk_32k>;
+	};
+};