Hi Rob,
On 4/25/19 9:57 PM, Rob Herring wrote:
> On Fri, Apr 19, 2019 at 04:19:24PM +0200, Lukasz Luba wrote:
>> The patch adds description for DT binding for a new Exynos5422 Dynamic
>> Memory Controller device.
>>
>> Signed-off-by: Lukasz Luba <l.luba@xxxxxxxxxxxxxxxxxxx>
>> ---
>> .../bindings/memory-controllers/exynos5422-dmc.txt | 73 ++++++++++++++++++++++
>> 1 file changed, 73 insertions(+)
>> create mode 100644 Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt
>>
>> diff --git a/Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt b/Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt
>> new file mode 100644
>> index 0000000..133b3cc
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/memory-controllers/exynos5422-dmc.txt
>> @@ -0,0 +1,73 @@
>> +* 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-bus".
>> +- clock-names : the name of clock used by the bus, "bus".
>> +- clocks : phandles for clock specified in "clock-names" property.
>> +- 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, chip information, clocks subsystem.
>> +- 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
>
> The memory node(s) should be a child of the memory controller IMO.
I have followed the TI code for LPDDR2. They use 'device-handle'
probably because the memory controller can be moved into the common
.dtsi and taken by reference in .dts in a proper board file.
The board .dts files might specify different DRAM chips and timings.
In Exynos case we will also have such situation: one memory controller
and a few different DRAM chips.
>
>> +- devfreq-events : phandles of the PPMU events used by the controller.
>> +
>> +Example:
>> +
>> + ppmu_dmc0_0: ppmu@10d00000 {
>> + compatible = "samsung,exynos-ppmu";
>> + reg = <0x10d00000 0x2000>;
>> + clocks = <&clock CLK_PCLK_PPMU_DREX0_0>;
>> + clock-names = "ppmu";
>> + status = "okay";
>
> Don't show 'status' in examples.
Thank you, I accidentally copied it from dt file.
Regards,
Lukasz
>
>> + 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>,
>> + <0x10000000 0x1000>, <0x10030000 0x1000>;
>> + 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_MX_MSPLL_CCORE_PHY>,
>> + <&clock CLK_MOUT_MCLK_CDREX>,
>> + <&clock CLK_DOUT_CLK2X_PHY0>,
>> + <&clock CLK_CLKM_PHY0>,
>> + <&clock CLK_CLKM_PHY1>;
>> + clock-names = "fout_spll",
>> + "mout_sclk_spll",
>> + "ff_dout_spll2",
>> + "fout_bpll",
>> + "mout_bpll",
>> + "sclk_bpll",
>> + "mout_mx_mspll_ccore",
>> + "mout_mx_mspll_ccore_phy",
>> + "mout_mclk_cdrex",
>> + "dout_clk2x_phy0",
>> + "clkm_phy0",
>> + "clkm_phy1";
>> + status = "okay";
>> + operating-points-v2 = <&dmc_opp_table>;
>> + devfreq-events = <&ppmu_event3_dmc0_0>, <&ppmu_event3_dmc0_1>,
>> + <&ppmu_event3_dmc1_0>, <&ppmu_event3_dmc1_1>;
>> + operating-points-v2 = <&dmc_opp_table>;
>> + device-handle = <&samsung_K3QF2F20DB>;
>> + vdd-supply = <&buck1_reg>;
>> + };
>> --
>> 2.7.4
>>
>
>
