clk: samsung: Add driver to control CLKOUT line on Exynos SoCs

This patch introduces a driver that handles configuration of CLKOUT pin
of Exynos SoCs that can be used to output certain clocks from inside of
the SoC to a dedicated output pin.

Signed-off-by: Tomasz Figa <t.figa@samsung.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arm/samsung/pmu.txt b/Documentation/devicetree/bindings/arm/samsung/pmu.txt
index 2a4ab046a8a1..f9865e77e0b0 100644
--- a/Documentation/devicetree/bindings/arm/samsung/pmu.txt
+++ b/Documentation/devicetree/bindings/arm/samsung/pmu.txt
@@ -12,8 +12,38 @@ Properties:
 
  - reg : offset and length of the register set.
 
+ - #clock-cells : must be <1>, since PMU requires once cell as clock specifier.
+                The single specifier cell is used as index to list of clocks
+                provided by PMU, which is currently:
+                        0 : SoC clock output (CLKOUT pin)
+
+ - clock-names : list of clock names for particular CLKOUT mux inputs in
+                following format:
+                        "clkoutN", where N is a decimal number corresponding to
+                        CLKOUT mux control bits value for given input, e.g.
+                                "clkout0", "clkout7", "clkout15".
+
+ - clocks : list of phandles and specifiers to all input clocks listed in
+                clock-names property.
+
 Example :
 pmu_system_controller: system-controller@10040000 {
         compatible = "samsung,exynos5250-pmu", "syscon";
         reg = <0x10040000 0x5000>;
+        #clock-cells = <1>;
+        clock-names = "clkout0", "clkout1", "clkout2", "clkout3",
+                        "clkout4", "clkout8", "clkout9";
+        clocks = <&clock CLK_OUT_DMC>, <&clock CLK_OUT_TOP>,
+                <&clock CLK_OUT_LEFTBUS>, <&clock CLK_OUT_RIGHTBUS>,
+                <&clock CLK_OUT_CPU>, <&clock CLK_XXTI>,
+                <&clock CLK_XUSBXTI>;
+};
+
+Example of clock consumer :
+
+usb3503: usb3503@08 {
+        /* ... */
+        clock-names = "refclk";
+        clocks = <&pmu_system_controller 0>;
+        /* ... */
 };