From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
Document how to modify per clock default behaviour
via the device-tree.
Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
---
.../bindings/clock/brcm,bcm2835-cprman.txt | 33 ++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/Documentation/devicetree/bindings/clock/brcm,bcm2835-cprman.txt b/Documentation/devicetree/bindings/clock/brcm,bcm2835-cprman.txt
index e56a1df..794c4ac 100644
--- a/Documentation/devicetree/bindings/clock/brcm,bcm2835-cprman.txt
+++ b/Documentation/devicetree/bindings/clock/brcm,bcm2835-cprman.txt
@@ -17,6 +17,26 @@ Required properties:
found in include/dt-bindings/clock/bcm2835.h
- reg: Specifies base physical address and size of the registers
- clocks: The external oscillator clock phandle
+- #address-cells number of cells required to define a clock
+- #size-cells Should be 0
+
+Subnodes:
+
+It is possible to apply optional settings per clock to modify clock
+selection behaviour.
+For each clock there may be a subnode that may contain the following:
+
+Required properties:
+- reg - clock id
+
+Optional properties:
+- parent-clock-names - list of parrent-clock names
+ this list is validated againt the default list
+ of parent clocks and is used in this order.
+- brcm,clock-selector - the clock selector to use
+- brcm,mash-max-order - the maximum order of the fractional divider
+- brcm,min-fract-div - the minimum divider required when using
+ the fractional divider
Example:
@@ -33,6 +53,19 @@ Example:
#clock-cells = <1>;
reg = <0x7e101000 0x2000>;
clocks = <&clk_osc>;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ /* custom settings for the PCM clock */
+ clock@BCM2835_CLOCK_PCM {
+ reg = <BCM2835_CLOCK_PCM>;
+ parent-clock-names = "xosc", "plld_per";
+ brcm,clock-selector =
+ <BCM2835_CHOOSE_CLOCK_INTEGER_THEN_FRAC>;
+ brcm,mash-max-order = <BCM2835_MASH_ORDER_3>;
+ brcm,min-fract-div = <20>;
+ };
};
i2c0: i2c@7e205000 {
--
1.7.10.4
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