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PM / devfreq: exynos: Update documentation for bus devices using passive governor
This patch updates the documentation for passive bus devices and adds the detailed example of Exynos3250. Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
This commit is contained in:
Chanwoo Choi
MyungJoo Ham
parent
403e0689d2
commit
a296cb5c35
@ -8,22 +8,46 @@ of the bus in runtime. To monitor the usage of each bus in runtime,
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the driver uses the PPMU (Platform Performance Monitoring Unit), which
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is able to measure the current load of sub-blocks.
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The Exynos SoC includes the various sub-blocks which have the each AXI bus.
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The each AXI bus has the owned source clock but, has not the only owned
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power line. The power line might be shared among one more sub-blocks.
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So, we can divide into two type of device as the role of each sub-block.
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There are two type of bus devices as following:
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- parent bus device
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- passive bus device
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Basically, parent and passive bus device share the same power line.
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The parent bus device can only change the voltage of shared power line
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and the rest bus devices (passive bus device) depend on the decision of
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the parent bus device. If there are three blocks which share the VDD_xxx
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power line, Only one block should be parent device and then the rest blocks
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should depend on the parent device as passive device.
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VDD_xxx |--- A block (parent)
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|--- B block (passive)
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|--- C block (passive)
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There are a little different composition among Exynos SoC because each Exynos
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SoC has different sub-blocks. Therefore, such difference should be specified
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in devicetree file instead of each device driver. In result, this driver
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is able to support the bus frequency for all Exynos SoCs.
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Required properties for bus device:
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Required properties for all bus devices:
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- compatible: Should be "samsung,exynos-bus".
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- clock-names : the name of clock used by the bus, "bus".
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- clocks : phandles for clock specified in "clock-names" property.
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- operating-points-v2: the OPP table including frequency/voltage information
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to support DVFS (Dynamic Voltage/Frequency Scaling) feature.
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Required properties only for parent bus device:
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- vdd-supply: the regulator to provide the buses with the voltage.
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- devfreq-events: the devfreq-event device to monitor the current utilization
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of buses.
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Optional properties for bus device:
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Required properties only for passive bus device:
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- devfreq: the parent bus device.
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Optional properties only for parent bus device:
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- exynos,saturation-ratio: the percentage value which is used to calibrate
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the performance count against total cycle count.
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- exynos,voltage-tolerance: the percentage value for bus voltage tolerance
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@ -34,7 +58,20 @@ Example1:
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power line (regulator). The MIF (Memory Interface) AXI bus is used to
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transfer data between DRAM and CPU and uses the VDD_MIF regulator.
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- power line(VDD_MIF) --> bus for DMC (Dynamic Memory Controller) block
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- MIF (Memory Interface) block
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: VDD_MIF |--- DMC (Dynamic Memory Controller)
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- INT (Internal) block
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: VDD_INT |--- LEFTBUS (parent device)
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|--- PERIL
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|--- MFC
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|--- G3D
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|--- RIGHTBUS
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|--- FSYS
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|--- LCD0
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|--- PERIR
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|--- ISP
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|--- CAM
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- MIF bus's frequency/voltage table
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-----------------------
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@ -47,6 +84,24 @@ Example1:
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|L5| 400000 |875000 |
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-----------------------
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- INT bus's frequency/voltage table
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----------------------------------------------------------
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|Block|LEFTBUS|RIGHTBUS|MCUISP |ISP |PERIL ||VDD_INT |
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| name| |LCD0 | | | || |
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| | |FSYS | | | || |
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| | |MFC | | | || |
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----------------------------------------------------------
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|Mode |*parent|passive |passive|passive|passive|| |
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----------------------------------------------------------
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|Lv |Frequency ||Voltage |
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----------------------------------------------------------
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|L1 |50000 |50000 |50000 |50000 |50000 ||900000 |
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|L2 |80000 |80000 |80000 |80000 |80000 ||900000 |
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|L3 |100000 |100000 |100000 |100000 |100000 ||1000000 |
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|L4 |134000 |134000 |200000 |200000 | ||1000000 |
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|L5 |200000 |200000 |400000 |300000 | ||1000000 |
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----------------------------------------------------------
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Example2 :
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The bus of DMC (Dynamic Memory Controller) block in exynos3250.dtsi
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is listed below:
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@ -85,6 +140,154 @@ Example2 :
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};
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};
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bus_leftbus: bus_leftbus {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_DIV_GDL>;
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clock-names = "bus";
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operating-points-v2 = <&bus_leftbus_opp_table>;
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status = "disabled";
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};
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bus_rightbus: bus_rightbus {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_DIV_GDR>;
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clock-names = "bus";
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operating-points-v2 = <&bus_leftbus_opp_table>;
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status = "disabled";
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};
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bus_lcd0: bus_lcd0 {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_DIV_ACLK_160>;
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clock-names = "bus";
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operating-points-v2 = <&bus_leftbus_opp_table>;
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status = "disabled";
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};
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bus_fsys: bus_fsys {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_DIV_ACLK_200>;
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clock-names = "bus";
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operating-points-v2 = <&bus_leftbus_opp_table>;
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status = "disabled";
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};
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bus_mcuisp: bus_mcuisp {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_DIV_ACLK_400_MCUISP>;
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clock-names = "bus";
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operating-points-v2 = <&bus_mcuisp_opp_table>;
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status = "disabled";
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};
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bus_isp: bus_isp {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_DIV_ACLK_266>;
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clock-names = "bus";
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operating-points-v2 = <&bus_isp_opp_table>;
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status = "disabled";
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};
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bus_peril: bus_peril {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_DIV_ACLK_100>;
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clock-names = "bus";
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operating-points-v2 = <&bus_peril_opp_table>;
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status = "disabled";
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};
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bus_mfc: bus_mfc {
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compatible = "samsung,exynos-bus";
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clocks = <&cmu CLK_SCLK_MFC>;
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clock-names = "bus";
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operating-points-v2 = <&bus_leftbus_opp_table>;
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status = "disabled";
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};
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bus_leftbus_opp_table: opp_table1 {
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compatible = "operating-points-v2";
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opp-shared;
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opp@50000000 {
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opp-hz = /bits/ 64 <50000000>;
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opp-microvolt = <900000>;
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};
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opp@80000000 {
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opp-hz = /bits/ 64 <80000000>;
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opp-microvolt = <900000>;
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};
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opp@100000000 {
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opp-hz = /bits/ 64 <100000000>;
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opp-microvolt = <1000000>;
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};
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opp@134000000 {
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opp-hz = /bits/ 64 <134000000>;
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opp-microvolt = <1000000>;
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};
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opp@200000000 {
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opp-hz = /bits/ 64 <200000000>;
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opp-microvolt = <1000000>;
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};
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};
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bus_mcuisp_opp_table: opp_table2 {
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compatible = "operating-points-v2";
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opp-shared;
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opp@50000000 {
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opp-hz = /bits/ 64 <50000000>;
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};
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opp@80000000 {
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opp-hz = /bits/ 64 <80000000>;
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};
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opp@100000000 {
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opp-hz = /bits/ 64 <100000000>;
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};
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opp@200000000 {
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opp-hz = /bits/ 64 <200000000>;
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};
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opp@400000000 {
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opp-hz = /bits/ 64 <400000000>;
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};
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};
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bus_isp_opp_table: opp_table3 {
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compatible = "operating-points-v2";
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opp-shared;
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opp@50000000 {
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opp-hz = /bits/ 64 <50000000>;
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};
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opp@80000000 {
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opp-hz = /bits/ 64 <80000000>;
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};
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opp@100000000 {
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opp-hz = /bits/ 64 <100000000>;
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};
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opp@200000000 {
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opp-hz = /bits/ 64 <200000000>;
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};
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opp@300000000 {
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opp-hz = /bits/ 64 <300000000>;
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};
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};
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bus_peril_opp_table: opp_table4 {
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compatible = "operating-points-v2";
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opp-shared;
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opp@50000000 {
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opp-hz = /bits/ 64 <50000000>;
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};
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opp@80000000 {
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opp-hz = /bits/ 64 <80000000>;
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};
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opp@100000000 {
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opp-hz = /bits/ 64 <100000000>;
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};
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};
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Usage case to handle the frequency and voltage of bus on runtime
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in exynos3250-rinato.dts is listed below:
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@ -93,3 +296,44 @@ Example2 :
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vdd-supply = <&buck1_reg>; /* VDD_MIF */
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status = "okay";
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};
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&bus_leftbus {
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devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
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vdd-supply = <&buck3_reg>;
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status = "okay";
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};
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&bus_rightbus {
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devfreq = <&bus_leftbus>;
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status = "okay";
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};
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&bus_lcd0 {
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devfreq = <&bus_leftbus>;
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status = "okay";
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};
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&bus_fsys {
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devfreq = <&bus_leftbus>;
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status = "okay";
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};
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&bus_mcuisp {
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devfreq = <&bus_leftbus>;
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status = "okay";
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};
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&bus_isp {
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devfreq = <&bus_leftbus>;
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status = "okay";
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};
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&bus_peril {
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devfreq = <&bus_leftbus>;
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status = "okay";
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};
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&bus_mfc {
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devfreq = <&bus_leftbus>;
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status = "okay";
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};
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