[PATCH 5/6] dt-bindings: clock: Document Exynos850 CMU bindings

Sam Protsenko
2021-09-14T15:56:32Z

Provide dt-schema documentation for Exynos850 SoC clock controller.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
---
.../clock/samsung,exynos850-clock.yaml | 190 ++++++++++++++++++
1 file changed, 190 insertions(+)
create mode 100644 Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml

diff --git a/Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml b/Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml
new file mode 100644
index 000000000000..b69ba4125421
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml
@@ -0,0 +1,190 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/samsung,exynos850-clock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos850 SoC clock controller
+
+maintainers:
+ - Sam Protsenko <semen.protsenko@linaro.org>
+ - Chanwoo Choi <cw00.choi@samsung.com>
+ - Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
+ - Sylwester Nawrocki <s.nawrocki@samsung.com>
+ - Tomasz Figa <tomasz.figa@gmail.com>
+
+description: |
+ Exynos850 clock controller is comprised of several CMU units, generating
+ clocks for different domains. Those CMU units are modeled as separate device
+ tree nodes, and might depend on each other. Root clocks in that clock tree are
+ two external clocks:: OSCCLK (26 MHz) and RTCCLK (32768 Hz). Those external
+ clocks must be defined as fixed-rate clocks in dts.
+
+ CMU_TOP is a top-level CMU, where all base clocks are prepared using PLLs and
+ dividers; all other leaf clocks (other CMUs) are usually derived from CMU_TOP.
+
+ Each clock is assigned an identifier and client nodes can use this identifier
+ to specify the clock which they consume. All clocks that available for usage
+ in clock consumer nodes are defined as preprocessor macros in
+ 'dt-bindings/clock/exynos850.h' header.
+
+properties:
+ compatible:
+ enum:
+ - samsung,exynos850-cmu-top
+ - samsung,exynos850-cmu-core
+ - samsung,exynos850-cmu-hsi
+ - samsung,exynos850-cmu-peri
+
+ clocks:
+ minItems: 1
+ maxItems: 5
+
+ clock-names:
+ minItems: 1
+ maxItems: 5
+
+ "#clock-cells":
+ const: 1
+
+ reg:
+ maxItems: 1
+
+allOf:
+ - if:
+ properties:
+ compatible:
+ contains:
+ const: samsung,exynos850-cmu-top
+
+ then:
+ properties:
+ clocks:
+ items:
+ - description: External reference clock (26 MHz)
+
+ clock-names:
+ items:
+ - const: oscclk
+
+ - if:
+ properties:
+ compatible:
+ contains:
+ const: samsung,exynos850-cmu-core
+
+ then:
+ properties:
+ clocks:
+ items:
+ - description: External reference clock (26 MHz)
+ - description: CMU_CORE bus clock (from CMU_TOP)
+ - description: CCI clock (from CMU_TOP)
+ - description: eMMC clock (from CMU_TOP)
+ - description: SSS clock (from CMU_TOP)
+
+ clock-names:
+ items:
+ - const: oscclk
+ - const: dout_core_bus
+ - const: dout_core_cci
+ - const: dout_core_mmc_embd
+ - const: dout_core_sss
+
+ - if:
+ properties:
+ compatible:
+ contains:
+ const: samsung,exynos850-cmu-hsi
+
+ then:
+ properties:
+ clocks:
+ items:
+ - description: External reference clock (26 MHz)
+ - description: External RTC clock (32768 Hz)
+ - description: CMU_HSI bus clock (from CMU_TOP)
+ - description: SD card clock (from CMU_TOP)
+ - description: "USB 2.0 DRD clock (from CMU_TOP)"
+
+ clock-names:
+ items:
+ - const: oscclk
+ - const: rtcclk
+ - const: dout_hsi_bus
+ - const: dout_hsi_mmc_card
+ - const: dout_hsi_usb20drd
+
+ - if:
+ properties:
+ compatible:
+ contains:
+ const: samsung,exynos850-cmu-peri
+
+ then:
+ properties:
+ clocks:
+ items:
+ - description: External reference clock (26 MHz)
+ - description: CMU_PERI bus clock (from CMU_TOP)
+ - description: UART clock (from CMU_TOP)
+ - description: Parent clock for HSI2C and SPI (from CMU_TOP)
+
+ clock-names:
+ items:
+ - const: oscclk
+ - const: dout_peri_bus
+ - const: dout_peri_uart
+ - const: dout_peri_ip
+
+required:
+ - compatible
+ - "#clock-cells"
+ - clocks
+ - clock-names
+ - reg
+
+additionalProperties: false
+
+examples:
+ # Clock controller node for CMU_PERI
+ - |
+ #include <dt-bindings/clock/exynos850.h>
+
+ cmu_peri: clock-controller@10030000 {
+ compatible = "samsung,exynos850-cmu-peri";
+ reg = <0x10030000 0x8000>;
+ #clock-cells = <1>;
+
+ clocks = <&oscclk>, <&cmu_top DOUT_PERI_BUS>,
+ <&cmu_top DOUT_PERI_UART>,
+ <&cmu_top DOUT_PERI_IP>;
+ clock-names = "oscclk", "dout_peri_bus",
+ "dout_peri_uart", "dout_peri_ip";
+ };
+
+ # External reference clock (should be provided in particular board DTS)
+ - |
+ oscclk: clock-oscclk {
+ compatible = "fixed-clock";
+ #clock-cells = <0>;
+ clock-output-names = "oscclk";
+ clock-frequency = <26000000>;
+ };
+
+ # UART controller node that consumes the clock generated by CMU_PERI
+ - |
+ #include <dt-bindings/clock/exynos850.h>
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+ serial_0: serial@13820000 {
+ compatible = "samsung,exynos850-uart";
+ reg = <0x13820000 0x100>;
+ interrupts = <GIC_SPI 227 IRQ_TYPE_LEVEL_HIGH>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&uart0_pins>;
+ clocks = <&cmu_peri GOUT_UART_PCLK>, <&cmu_peri GOUT_UART_IPCLK>;
+ clock-names = "uart", "clk_uart_baud0";
+ };
+
+...
--
2.30.2