dt-bindings: clock: at91: new sckc bindings

Remove the need for child nodes in the sckc binding to be able to remove
dtc warnings and have a more modern binding.

Also document optional properties.

Cc: Rob Herring <robh@kernel.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

Documentation/devicetree/bindings/clock/at91-clock.txt

@@ -8,29 +8,23 @@ Slow Clock controller:
 
 Required properties:
 - compatible : shall be one of the following:
-	"atmel,at91sam9x5-sckc" or
+	"atmel,at91sam9x5-sckc",
+	"atmel,sama5d3-sckc" or
 	"atmel,sama5d4-sckc":
 		at91 SCKC (Slow Clock Controller)
-		This node contains the slow clock definitions.
-
-	"atmel,at91sam9x5-clk-slow-osc":
-		at91 slow oscillator
-
-	"atmel,at91sam9x5-clk-slow-rc-osc":
-		at91 internal slow RC oscillator
-- reg : defines the IO memory reserved for the SCKC.
-- #size-cells : shall be 0 (reg is used to encode clk id).
-- #address-cells : shall be 1 (reg is used to encode clk id).
+- #clock-cells : shall be 0.
+- clocks : shall be the input parent clock phandle for the clock.
 
+Optional properties:
+- atmel,osc-bypass : boolean property. Set this when a clock signal is directly
+  provided on XIN.
 
 For example:
-	sckc: sckc@fffffe50 {
-		compatible = "atmel,sama5d3-pmc";
-		reg = <0xfffffe50 0x4>
-		#size-cells = <0>;
-		#address-cells = <1>;
-
-		/* put at91 slow clocks here */
+	sckc@fffffe50 {
+		compatible = "atmel,at91sam9x5-sckc";
+		reg = <0xfffffe50 0x4>;
+		clocks = <&slow_xtal>;
+		#clock-cells = <0>;
 	};
 
 Power Management Controller (PMC):