summaryrefslogtreecommitdiff
path: root/Documentation/devicetree/bindings/clock
diff options
context:
space:
mode:
authorIlia Lin <ilialin@codeaurora.org>2020-07-03 11:49:43 +0300
committerStephen Boyd <sboyd@kernel.org>2020-07-11 03:09:20 +0300
commit2283f9e03328b2437abddf446027931631af1031 (patch)
treef0a758d25ecc78c3b24d3387f3ec0810caf539be /Documentation/devicetree/bindings/clock
parent6d0efeb14bbe2350a94ba07b403a686d731c5179 (diff)
downloadlinux-2283f9e03328b2437abddf446027931631af1031.tar.xz
dt-bindings: clk: qcom: Add bindings for CPU clock for msm8996
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> Link: https://lore.kernel.org/r/1593766185-16346-4-git-send-email-loic.poulain@linaro.org Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Diffstat (limited to 'Documentation/devicetree/bindings/clock')
-rw-r--r--Documentation/devicetree/bindings/clock/qcom,msm8996-apcc.yaml56
1 files changed, 56 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/clock/qcom,msm8996-apcc.yaml b/Documentation/devicetree/bindings/clock/qcom,msm8996-apcc.yaml
new file mode 100644
index 000000000000..d673edeed98d
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/qcom,msm8996-apcc.yaml
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/qcom,kryocc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm clock controller for MSM8996 CPUs
+
+maintainers:
+ - Loic Poulain <loic.poulain@linaro.org>
+
+description: |
+ Qualcomm CPU clock controller for MSM8996 CPUs, clock 0 is for Power cluster
+ and clock 1 is for Perf cluster.
+
+properties:
+ compatible:
+ enum:
+ - qcom,msm8996-apcc
+
+ reg:
+ maxItems: 1
+
+ '#clock-cells':
+ const: 1
+
+ clocks:
+ items:
+ - description: Primary PLL clock for power cluster (little)
+ - description: Primary PLL clock for perf cluster (big)
+ - description: Alternate PLL clock for power cluster (little)
+ - description: Alternate PLL clock for perf cluster (big)
+
+ clock-names:
+ items:
+ - const: pwrcl_pll
+ - const: perfcl_pll
+ - const: pwrcl_alt_pll
+ - const: perfcl_alt_pll
+
+required:
+ - compatible
+ - reg
+ - '#clock-cells'
+
+additionalProperties: false
+
+examples:
+ # Example for msm8996
+ - |
+ kryocc: clock-controller@6400000 {
+ compatible = "qcom,msm8996-apcc";
+ reg = <0x6400000 0x90000>;
+ #clock-cells = <1>;
+ };
+...