From be95d2c7d918b2b7b973378a1e92bdc6559c21f9 Mon Sep 17 00:00:00 2001 From: Sylwester Nawrocki Date: Fri, 9 Sep 2016 10:09:05 +0200 Subject: clk: samsung: Add support for EPLL on exynos5410 This patch adds code instantiating the EPLL, which is used as the audio subsystem's root clock. The requirement to specify the external root clock in clocks property is documented. Having the consumer 'clocks' property ensures proper initialization order by explicitly specifying dependencies in DT. It prevents situations when the SoC's clock controller driver has initialized, the external oscillator clock is not yet registered and setting clock frequencies through assigned-clock-rates property doesn't work properly due to unknown external oscillator frequency. Signed-off-by: Sylwester Nawrocki Reviewed-by: Chanwoo Choi --- .../devicetree/bindings/clock/exynos5410-clock.txt | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) (limited to 'Documentation/devicetree/bindings/clock/exynos5410-clock.txt') diff --git a/Documentation/devicetree/bindings/clock/exynos5410-clock.txt b/Documentation/devicetree/bindings/clock/exynos5410-clock.txt index aeab635b07b5..4527de3ea205 100644 --- a/Documentation/devicetree/bindings/clock/exynos5410-clock.txt +++ b/Documentation/devicetree/bindings/clock/exynos5410-clock.txt @@ -12,24 +12,29 @@ Required Properties: - #clock-cells: should be 1. +- clocks: should contain an entry specifying the root clock from external + oscillator supplied through XXTI or XusbXTI pin. This clock should be + defined using standard clock bindings with "fin_pll" clock-output-name. + That clock is being passed internally to the 9 PLLs. + All available clocks are defined as preprocessor macros in dt-bindings/clock/exynos5410.h header and can be used in device tree sources. -External clock: - -There is clock that is generated outside the SoC. It -is expected that it is defined using standard clock bindings -with following clock-output-name: - - - "fin_pll" - PLL input clock from XXTI - Example 1: An example of a clock controller node is listed below. + fin_pll: xxti { + compatible = "fixed-clock"; + clock-frequency = <24000000>; + clock-output-names = "fin_pll"; + #clock-cells = <0>; + }; + clock: clock-controller@0x10010000 { compatible = "samsung,exynos5410-clock"; reg = <0x10010000 0x30000>; #clock-cells = <1>; + clocks = <&fin_pll>; }; Example 2: UART controller node that consumes the clock generated by the clock -- cgit v1.2.3