| Message ID | 1527079981-11179-6-git-send-email-ilialin@codeaurora.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/Documentation/devicetree/bindings/clock/qcom,kryocc.txt b/Documentation/devicetree/bindings/clock/qcom,kryocc.txt new file mode 100644 index 0000000..8458783 --- /dev/null +++ b/Documentation/devicetree/bindings/clock/qcom,kryocc.txt @@ -0,0 +1,17 @@ +Qualcomm CPUSS clock controller for Kryo CPUs +---------------------------------------------------- + +Required properties : +- compatible : shall contain only one of the following: + + "qcom,msm8996-apcc" + +- reg : shall contain base register location and length +- #clock-cells : shall contain 1 + +Example: + kryocc: clock-controller@6400000 { + compatible = "qcom,msm8996-apcc"; + reg = <0x6400000 0x90000>; + #clock-cells = <1>; + };
Each of the CPU clusters (Power and Perf) on msm8996 are clocked via 2 PLLs, a primary and alternate. There are also 2 Mux'es, a primary and secondary all connected together as shown below +-------+ XO | | +------------------>0 | | | PLL/2 | SMUX +----+ +------->1 | | | | | | | +-------+ | +-------+ | +---->0 | | | | +---------------+ | +----------->1 | CPU clk |Primary PLL +----+ PLL_EARLY | | +------> | +------+-----------+ +------>2 PMUX | +---------------+ | | | | | +------+ | +-->3 | +--^+ ACD +-----+ | +-------+ +---------------+ +------+ | |Alt PLL | | | +---------------------------+ +---------------+ PLL_EARLY The primary PLL is what drives the CPU clk, except for times when we are reprogramming the PLL itself (for rate changes) when we temporarily switch to an alternate PLL. A subsequent patch adds support to switch between primary and alternate PLL during rate changes. The primary PLL operates on a single VCO range, between 600MHz and 3GHz. However the CPUs do support OPPs with frequencies between 300MHz and 600MHz. In order to support running the CPUs at those frequencies we end up having to lock the PLL at twice the rate and drive the CPU clk via the PLL/2 output and SMUX. Signed-off-by: Ilia Lin <ilialin@codeaurora.org> Reviewed-by: Rob Herring <robh@kernel.org> --- Documentation/devicetree/bindings/clock/qcom,kryocc.txt | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/qcom,kryocc.txt