* Rockchip rk3399 DMC(Dynamic Memory Controller) device

Required properties:
- compatible:		 Must be "rockchip,rk3399-dmc".
- devfreq-events:	 Node to get DDR loading, Refer to
			 Documentation/devicetree/bindings/devfreq/
			 rockchip-dfi.txt
- interrupts:		 The interrupt number to the CPU. The interrupt
			 specifier format depends on the interrupt controller.
			 It should be DCF interrupts, when DDR dvfs finish,
			 it will happen.
- clocks:		 Phandles for clock specified in "clock-names" property
- clock-names :		 The name of clock used by the DFI, must be
			 "pclk_ddr_mon";
- operating-points-v2:	 Refer to Documentation/devicetree/bindings/power/opp.txt
			 for details.
- center-supply:	 DMC supply node.
- status:		 Marks the node enabled/disabled.

Following properties are ddr timing:

- rockchip,dram_speed_bin :	  Value reference include/dt-bindings/clock/ddr.h,
				  it select ddr3 cl-trp-trcd type, default value
				  "DDR3_DEFAULT".it must selected according to
				  "Speed Bin" in ddr3 datasheet, DO NOT use
				  smaller "Speed Bin" than ddr3 exactly is.

- rockchip,pd_idle :		  Config the PD_IDLE value, defined the power-down
				  idle period, memories are places into power-down
				  mode if bus is idle for PD_IDLE DFI clocks.

- rockchip,sr_idle :		  Configure the SR_IDLE value, defined the
				  selfrefresh idle period, memories are places
				  into self-refresh mode if bus is idle for
				  SR_IDLE*1024 DFI clocks (DFI clocks freq is
				  half of dram's clocks), defaule value is "0".

- rockchip,sr_mc_gate_idle :	  Defined the self-refresh with memory and
				  controller clock gating idle period, memories
				  are places into self-refresh mode and memory
				  controller clock arg gating if bus is idle for
				  sr_mc_gate_idle*1024 DFI clocks.

- rockchip,srpd_lite_idle :	  Defined the self-refresh power down idle
				  period, memories are places into self-refresh
				  power down mode if bus is idle for
				  srpd_lite_idle*1024 DFI clocks. This parameter
				  is for LPDDR4 only.

- rockchip,standby_idle :	  Defined the standby idle period, memories are
				  places into self-refresh than controller, pi,
				  phy and dram clock will gating if bus is idle
				  for standby_idle * DFI clocks.

- rockchip,dram_dll_disb_freq :  It's defined the DDR3 dll bypass frequency in
				  MHz, when ddr freq less than DRAM_DLL_DISB_FREQ,
				  ddr3 dll will bypssed note: if dll was bypassed,
				  the odt also stop working.

- rockchip,phy_dll_disb_freq :	  Defined the PHY dll bypass frequency in
				  MHz (Mega Hz), when ddr freq less than
				  DRAM_DLL_DISB_FREQ, phy dll will bypssed.
				  note: phy dll and phy odt are independent.

- rockchip,ddr3_odt_disb_freq :  When dram type is DDR3, this parameter defined
				  the odt disable frequency in MHz (Mega Hz),
				  when ddr frequency less then ddr3_odt_disb_freq,
				  the odt on dram side and controller side are
				  both disabled.

- rockchip,ddr3_drv :		  When dram type is DDR3, this parameter define
				  the dram side driver stength in ohm, default
				  value is DDR3_DS_40ohm.

- rockchip,ddr3_odt :		  When dram type is DDR3, this parameter define
				  the dram side ODT stength in ohm, default value
				  is DDR3_ODT_120ohm.

- rockchip,phy_ddr3_ca_drv :	  When dram type is DDR3, this parameter define
				  the phy side CA line(incluing command line,
				  address line and clock line) driver strength.
				  Default value is PHY_DRV_ODT_40.

- rockchip,phy_ddr3_dq_drv :	  When dram type is DDR3, this parameter define
				  the phy side DQ line(incluing DQS/DQ/DM line)
				  driver strength. default value is PHY_DRV_ODT_40.

- rockchip,phy_ddr3_odt : 	  When dram type is DDR3, this parameter define the
				  phy side odt strength, default value is
				  PHY_DRV_ODT_240.

- rockchip,lpddr3_odt_disb_freq : When dram type is LPDDR3, this parameter defined
				  then odt disable frequency in MHz (Mega Hz),
				  when ddr frequency less then ddr3_odt_disb_freq,
				  the odt on dram side and controller side are
				  both disabled.

- rockchip,lpddr3_drv :	  When dram type is LPDDR3, this parameter define
				  the dram side driver stength in ohm, default
				  value is LP3_DS_34ohm.

- rockchip,lpddr3_odt :	  When dram type is LPDDR3, this parameter define
				  the dram side ODT stength in ohm, default value
				  is LP3_ODT_240ohm.

- rockchip,phy_lpddr3_ca_drv :	  When dram type is LPDDR3, this parameter define
				  the phy side CA line(incluing command line,
				  address line and clock line) driver strength.
				  default value is PHY_DRV_ODT_40.

- rockchip,phy_lpddr3_dq_drv :	  When dram type is LPDDR3, this parameter define
				  the phy side DQ line(incluing DQS/DQ/DM line)
				  driver strength. default value is
				  PHY_DRV_ODT_40.

- rockchip,phy_lpddr3_odt : 	  When dram type is LPDDR3, this parameter define
				  the phy side odt strength, default value is
				  PHY_DRV_ODT_240.

- rockchip,lpddr4_odt_disb_freq : When dram type is LPDDR4, this parameter
				  defined the odt disable frequency in
				  MHz (Mega Hz), when ddr frequency less then
				  ddr3_odt_disb_freq, the odt on dram side and
				  controller side are both disabled.

- rockchip,lpddr4_drv :	  When dram type is LPDDR4, this parameter define
				  the dram side driver stength in ohm, default
				  value is LP4_PDDS_60ohm.

- rockchip,lpddr4_dq_odt : 	  When dram type is LPDDR4, this parameter define
				  the dram side ODT on dqs/dq line stength in ohm,
				  default value is LP4_DQ_ODT_40ohm.

- rockchip,lpddr4_ca_odt :	  When dram type is LPDDR4, this parameter define
				  the dram side ODT on ca line stength in ohm,
				  default value is LP4_CA_ODT_40ohm.

- rockchip,phy_lpddr4_ca_drv :	  When dram type is LPDDR4, this parameter define
				  the phy side  CA line(incluing command address
				  line) driver strength. default value is
				  PHY_DRV_ODT_40.

- rockchip,phy_lpddr4_ck_cs_drv : When dram type is LPDDR4, this parameter define
				  the phy side clock line and cs line driver
				  strength. default value is PHY_DRV_ODT_80.

- rockchip,phy_lpddr4_dq_drv :	  When dram type is LPDDR4, this parameter define
				  the phy side DQ line(incluing DQS/DQ/DM line)
				  driver strength. default value is PHY_DRV_ODT_80.

- rockchip,phy_lpddr4_odt :	  When dram type is LPDDR4, this parameter define
				  the phy side odt strength, default value is
				  PHY_DRV_ODT_60.

Example:
	dmc_opp_table: dmc_opp_table {
		compatible = "operating-points-v2";

		opp00 {
			opp-hz = /bits/ 64 <300000000>;
			opp-microvolt = <900000>;
		};
		opp01 {
			opp-hz = /bits/ 64 <666000000>;
			opp-microvolt = <900000>;
		};
	};

	dmc: dmc {
		compatible = "rockchip,rk3399-dmc";
		devfreq-events = <&dfi>;
		interrupts = <GIC_SPI 1 IRQ_TYPE_LEVEL_HIGH>;
		clocks = <&cru SCLK_DDRCLK>;
		clock-names = "dmc_clk";
		operating-points-v2 = <&dmc_opp_table>;
		center-supply = <&ppvar_centerlogic>;
		upthreshold = <15>;
		downdifferential = <10>;
		rockchip,ddr3_speed_bin = <21>;
		rockchip,pd_idle = <0x40>;
		rockchip,sr_idle = <0x2>;
		rockchip,sr_mc_gate_idle = <0x3>;
		rockchip,srpd_lite_idle	= <0x4>;
		rockchip,standby_idle = <0x2000>;
		rockchip,dram_dll_dis_freq = <300>;
		rockchip,phy_dll_dis_freq = <125>;
		rockchip,auto_pd_dis_freq = <666>;
		rockchip,ddr3_odt_dis_freq = <333>;
		rockchip,ddr3_drv = <DDR3_DS_40ohm>;
		rockchip,ddr3_odt = <DDR3_ODT_120ohm>;
		rockchip,phy_ddr3_ca_drv = <PHY_DRV_ODT_40>;
		rockchip,phy_ddr3_dq_drv = <PHY_DRV_ODT_40>;
		rockchip,phy_ddr3_odt = <PHY_DRV_ODT_240>;
		rockchip,lpddr3_odt_dis_freq = <333>;
		rockchip,lpddr3_drv = <LP3_DS_34ohm>;
		rockchip,lpddr3_odt = <LP3_ODT_240ohm>;
		rockchip,phy_lpddr3_ca_drv = <PHY_DRV_ODT_40>;
		rockchip,phy_lpddr3_dq_drv = <PHY_DRV_ODT_40>;
		rockchip,phy_lpddr3_odt = <PHY_DRV_ODT_240>;
		rockchip,lpddr4_odt_dis_freq = <333>;
		rockchip,lpddr4_drv = <LP4_PDDS_60ohm>;
		rockchip,lpddr4_dq_odt = <LP4_DQ_ODT_40ohm>;
		rockchip,lpddr4_ca_odt = <LP4_CA_ODT_40ohm>;
		rockchip,phy_lpddr4_ca_drv = <PHY_DRV_ODT_40>;
		rockchip,phy_lpddr4_ck_cs_drv = <PHY_DRV_ODT_80>;
		rockchip,phy_lpddr4_dq_drv = <PHY_DRV_ODT_80>;
		rockchip,phy_lpddr4_odt = <PHY_DRV_ODT_60>;
		status = "disabled";
	};