dt: add clock binding doc to primecell bindings

Add clock binding information for primecell peripherals. For most, a
clock input name of "apb_pclk" is required. Any primecell peripherals
which are different will need to be documented separately.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arm/primecell.txt b/Documentation/devicetree/bindings/arm/primecell.txt
index 951ca46789d4..64fc82bc8928 100644
--- a/Documentation/devicetree/bindings/arm/primecell.txt
+++ b/Documentation/devicetree/bindings/arm/primecell.txt
@@ -13,11 +13,17 @@ Required properties:
 Optional properties:
 
 - arm,primecell-periphid : Value to override the h/w value with
+- clocks : From common clock binding. First clock is phandle to clock for apb
+        pclk. Additional clocks are optional and specific to those peripherals.
+- clock-names : From common clock binding. Shall be "apb_pclk" for first clock.
 
 Example:
 
 serial@fff36000 {
         compatible = "arm,pl011", "arm,primecell";
         arm,primecell-periphid = <0x00341011>;
+        clocks = <&pclk>;
+        clock-names = "apb_pclk";
+        
 };