dt-bindings: mailbox: qcom: Document the APCS clock binding

Update the binding documentation for APCS to mention that the APCS
hardware block also expose a clock controller functionality.

The APCS clock controller is a mux and half-integer divider. It has the
main CPU PLL as an input and provides the clock for the application CPU.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

1 files changed, 18 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.txt b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.txt
index fb961c310f44..16964f0c1773 100644
--- a/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.txt
+++ b/Documentation/devicetree/bindings/mailbox/qcom,apcs-kpss-global.txt
@@ -15,12 +15,21 @@ platforms.
         Usage: required
         Value type: <prop-encoded-array>
         Definition: must specify the base address and size of the global block
+- clocks:
+        Usage: required if #clocks-cells property is present
+        Value type: <phandle>
+        Definition: phandle to the input PLL, which feeds the APCS mux/divider
 
 - #mbox-cells:
         Usage: required
         Value type: <u32>
         Definition: as described in mailbox.txt, must be 1
 
+- #clock-cells:
+        Usage: optional
+        Value type: <u32>
+        Definition: as described in clock.txt, must be 0
+
 
 = EXAMPLE
 The following example describes the APCS HMSS found in MSM8996 and part of the
@@ -44,3 +53,12 @@ GLINK RPM referencing the "rpm_hlos" doorbell therein.
                 mbox-names = "rpm_hlos";
         };
 
+Below is another example of the APCS binding on MSM8916 platforms:
+
+        apcs: mailbox@b011000 {
+                compatible = "qcom,msm8916-apcs-kpss-global";
+                reg = <0xb011000 0x1000>;
+                #mbox-cells = <1>;
+                clocks = <&a53pll>;
+                #clock-cells = <0>;
+        };