| * Exynos5422 frequency and voltage scaling for Dynamic Memory Controller device |
| |
| The Samsung Exynos5422 SoC has DMC (Dynamic Memory Controller) to which the DRAM |
| memory chips are connected. The driver is to monitor the controller in runtime |
| and switch frequency and voltage. To monitor the usage of the controller in |
| runtime, the driver uses the PPMU (Platform Performance Monitoring Unit), which |
| is able to measure the current load of the memory. |
| When 'userspace' governor is used for the driver, an application is able to |
| switch the DMC and memory frequency. |
| |
| Required properties for DMC device for Exynos5422: |
| - compatible: Should be "samsung,exynos5422-dmc". |
| - clocks : list of clock specifiers, must contain an entry for each |
| required entry in clock-names for CLK_FOUT_SPLL, CLK_MOUT_SCLK_SPLL, |
| CLK_FF_DOUT_SPLL2, CLK_FOUT_BPLL, CLK_MOUT_BPLL, CLK_SCLK_BPLL, |
| CLK_MOUT_MX_MSPLL_CCORE, CLK_MOUT_MX_MSPLL_CCORE_PHY, CLK_MOUT_MCLK_CDREX, |
| - clock-names : should include "fout_spll", "mout_sclk_spll", "ff_dout_spll2", |
| "fout_bpll", "mout_bpll", "sclk_bpll", "mout_mx_mspll_ccore", |
| "mout_mclk_cdrex" entries |
| - devfreq-events : phandles for PPMU devices connected to this DMC. |
| - vdd-supply : phandle for voltage regulator which is connected. |
| - reg : registers of two CDREX controllers. |
| - operating-points-v2 : phandle for OPPs described in v2 definition. |
| - device-handle : phandle of the connected DRAM memory device. For more |
| information please refer to documentation file: |
| Documentation/devicetree/bindings/ddr/lpddr3.txt |
| - devfreq-events : phandles of the PPMU events used by the controller. |
| - samsung,syscon-clk : phandle of the clock register set used by the controller, |
| these registers are used for enabling a 'pause' feature and are not |
| exposed by clock framework but they must be used in a safe way. |
| The register offsets are in the driver code and specyfic for this SoC |
| type. |
| |
| Optional properties for DMC device for Exynos5422: |
| - interrupt-parent : The parent interrupt controller. |
| - interrupts : Contains the IRQ line numbers for the DMC internal performance |
| event counters in DREX0 and DREX1 channels. Align with specification of the |
| interrupt line(s) in the interrupt-parent controller. |
| - interrupt-names : IRQ names "drex_0" and "drex_1", the order should be the |
| same as in the 'interrupts' list above. |
| |
| Example: |
| |
| ppmu_dmc0_0: ppmu@10d00000 { |
| compatible = "samsung,exynos-ppmu"; |
| reg = <0x10d00000 0x2000>; |
| clocks = <&clock CLK_PCLK_PPMU_DREX0_0>; |
| clock-names = "ppmu"; |
| events { |
| ppmu_event_dmc0_0: ppmu-event3-dmc0_0 { |
| event-name = "ppmu-event3-dmc0_0"; |
| }; |
| }; |
| }; |
| |
| dmc: memory-controller@10c20000 { |
| compatible = "samsung,exynos5422-dmc"; |
| reg = <0x10c20000 0x10000>, <0x10c30000 0x10000>; |
| clocks = <&clock CLK_FOUT_SPLL>, |
| <&clock CLK_MOUT_SCLK_SPLL>, |
| <&clock CLK_FF_DOUT_SPLL2>, |
| <&clock CLK_FOUT_BPLL>, |
| <&clock CLK_MOUT_BPLL>, |
| <&clock CLK_SCLK_BPLL>, |
| <&clock CLK_MOUT_MX_MSPLL_CCORE>, |
| <&clock CLK_MOUT_MCLK_CDREX>; |
| clock-names = "fout_spll", |
| "mout_sclk_spll", |
| "ff_dout_spll2", |
| "fout_bpll", |
| "mout_bpll", |
| "sclk_bpll", |
| "mout_mx_mspll_ccore", |
| "mout_mclk_cdrex"; |
| operating-points-v2 = <&dmc_opp_table>; |
| devfreq-events = <&ppmu_event3_dmc0_0>, <&ppmu_event3_dmc0_1>, |
| <&ppmu_event3_dmc1_0>, <&ppmu_event3_dmc1_1>; |
| device-handle = <&samsung_K3QF2F20DB>; |
| vdd-supply = <&buck1_reg>; |
| samsung,syscon-clk = <&clock>; |
| interrupt-parent = <&combiner>; |
| interrupts = <16 0>, <16 1>; |
| interrupt-names = "drex_0", "drex_1"; |
| }; |