This patch introduce device tree binding for the Exynos4's busfreq driver. The Exynos4's busfreq driver support DVFS(Dynamic Voltage Frequency Scaling) of Exynos4 memory bus to optimize power-consumption on runtime state. Exynos4's busfreq driver need the utilization of memory bus. So, busfreq driver use PPMU_DMC0/PPMU_DMC1 IP among various PPMU(Performance Profiling Monitoring Units) which provide the data of read/write counters on memory bus. This driver adjust the frequency/voltage of memory bus according to PPMU_DMC0/PPMU_DMC1 counters.
Signed-off-by: Chanwoo Choi <[email protected]> --- .../devicetree/bindings/devfreq/exynos4_bus.txt | 50 ++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 Documentation/devicetree/bindings/devfreq/exynos4_bus.txt diff --git a/Documentation/devicetree/bindings/devfreq/exynos4_bus.txt b/Documentation/devicetree/bindings/devfreq/exynos4_bus.txt new file mode 100644 index 0000000..bd397ed --- /dev/null +++ b/Documentation/devicetree/bindings/devfreq/exynos4_bus.txt @@ -0,0 +1,50 @@ + +Exynos4 Memory Bus frequency driver +----------------------------------- + +Exynos4 SoC need Busfreq (Memory Bus frequency) driver to support DVFS (Dynamic +Voltage Frequency Scaling) of Exynos4 SoC's memory bus. This driver controls +dynamically the frequency/voltage of memory bus to optimize power-consumption +of memory bus. When checking the utilization of memory bus, Exynos4's busfreq +driver uses PPMU_DMC0/PPMU_DMC1 (Performance Profiling Monitoring Units) +which provide the data of read/write counters on memory bus. + +Required properties: +- compatible : should contain Exynos4 SoC type as following: + - "samsung,exynos4210-busfreq" for Exynos4210 + - "samsung,exynos4x12-busfreq" for Exynos4x12 +- reg : physical address of PPMU_DMC0/PPMU_DMC1 register and length + for memory mapping +- clocks : phandles to clock-controller and clock number of PPMU_DMC0 + /PPMU_DMC1 +- clock-names : clock names for PPMU_DMC0/PPMU_DMC1 + - "ppmudmc0" for PPMU_DMC0 + - "ppmudmc1" for PPMU_DMC1 +- vdd_int-supply: regulator for interface block of Exynos4 SoC + +Optional properties: +- vdd_mif-supply: regulator for DMC block if using Exynos4x12 SoC + +Example: +For Exynos4210 busfreq, + + busfreq@106A0000 { + compatible = "samsung,exynos4210-busfreq"; + reg = <0x106A0000 0x2000>, <0x106B0000 0x2000>; + clocks = <&clock CLK_PPMUDMC0>, <&clock CLK_PPMUDMC1>; + clock-names = "ppmudmc0", "ppmudmc1"; + + vdd_int-supply = <&buck3_reg>; + }; + +For Exynos4x12 busfreq, + + busfreq@106A0000 { + compatible = "samsung,exynos4x12-busfreq"; + reg = <0x106A0000 0x2000>, <0x106B0000 0x2000>; + clocks = <&clock CLK_PPMUDMC0>, <&clock CLK_PPMUDMC1>; + clock-names = "ppmudmc0", "ppmudmc1"; + + vdd_int-supply = <&buck3_reg>; + vdd_mif-suppy = <&buck1_reg>; + }; -- 1.8.0 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
