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Subject: Re: [PATCH v5 4/8] dt-bindings: devfreq: add Exynos5422 DMC device
 description
To:     Chanwoo Choi <cw00.choi@samsung.com>, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
        linux-samsung-soc@vger.kernel.org
Cc:     b.zolnierkie@samsung.com, krzk@kernel.org, kgene@kernel.org,
        kyungmin.park@samsung.com, m.szyprowski@samsung.com,
        s.nawrocki@samsung.com, myungjoo.ham@samsung.com
From:   Lukasz Luba <l.luba@partner.samsung.com>
Message-ID: <1800b874-75c3-420d-71df-9b9a8e7ad1c8@partner.samsung.com>
Date:   Wed, 6 Mar 2019 08:14:55 +0100
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Hi Chanwoo,

On 3/6/19 5:18 AM, Chanwoo Choi wrote:
> Hi Lukasz,
> 
> On 19. 3. 5. 오후 7:19, 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@partner.samsung.com>
>> ---
>>   .../devicetree/bindings/devfreq/exynos5422-dmc.txt | 177 +++++++++++++++++++++
>>   1 file changed, 177 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/devfreq/exynos5422-dmc.txt
>>
>> diff --git a/Documentation/devicetree/bindings/devfreq/exynos5422-dmc.txt b/Documentation/devicetree/bindings/devfreq/exynos5422-dmc.txt
>> new file mode 100644
>> index 0000000..0e73e98
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/devfreq/exynos5422-dmc.txt
>> @@ -0,0 +1,177 @@
>> +* 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 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.
> 
> 
> I already replied with following comments on v4 patch[1].
> But, you didn't reply anything. We can reduce the duplicate
> review by keeping the basic review rule.
I have lost these changes while I was adding the OPPs, timings into the
dt-binding.
> 
> - Re: [PATCH v4 5/8] dt-bindings: devfreq: add Exynos5422 DMC device description
> [1] https://do-db2.lkml.org/lkml/2019/2/3/64
> 
> 
> [Following comments were replied on v4 patch[1]]
> 
>> +- compatible: Should be "samsung,exynos5422-bus".
> 
> The compatible name is wrong.
> - exynos5422-bus -> exynos5422-dmc
> 
>> +- clock-names : the name of clock used by the bus, "bus".
> 
> 'bus' is right?
right
> 
>> +- clocks : phandles for clock specified in "clock-names" property.
>> +- devfreq-events : phandles for PPMU devices connected to this DMC.
> 
> The dt-binging file doesn't contain the any description for 'reg' properties.
There are 3 regs: cdrex0, cdrex1, chip_id. I will add this description.

The patch set has this OPPs and timings coming from DT as you requested
but I am not sure if it is in the right place in the DT.
Thus dt-binding you may consider as 'in-progress' till the DT entries
are fixed

Regards,
Lukasz
> 
> 
> 
>> +
>> +The example definition of a DMC and PPMU devices declared in DT is shown below:
>> +
>> +	ppmu_dmc0_0: ppmu@10d00000 {
>> +		compatible = "samsung,exynos-ppmu";
>> +		reg = <0x10d00000 0x2000>;
>> +		clocks = <&clock CLK_PCLK_PPMU_DREX0_0>;
>> +		clock-names = "ppmu";
>> +		status = "okay";
>> +		events {
>> +			ppmu_event_dmc0_0: ppmu-event3-dmc0_0 {
>> +				event-name = "ppmu-event3-dmc0_0";
>> +			};
>> +		};
>> +	};
>> +
>> +
>> +	ppmu_dmc0_1: ppmu@10d10000 {
>> +		compatible = "samsung,exynos-ppmu";
>> +		reg = <0x10d10000 0x2000>;
>> +		clocks = <&clock CLK_PCLK_PPMU_DREX0_1>;
>> +		clock-names = "ppmu";
>> +		status = "okay";
>> +		events {
>> +			ppmu_event_dmc0_1: ppmu-event3-dmc0_1 {
>> +				event-name = "ppmu-event3-dmc0_1";
>> +			};
>> +		};
>> +	};
>> +
>> +	ppmu_dmc1_0: ppmu@10d10000 {
>> +		compatible = "samsung,exynos-ppmu";
>> +		reg = <0x10d60000 0x2000>;
>> +		clocks = <&clock CLK_PCLK_PPMU_DREX1_0>;
>> +		clock-names = "ppmu";
>> +		status = "okay";
>> +		events {
>> +			ppmu_event_dmc1_0: ppmu-event3-dmc1_0 {
>> +				event-name = "ppmu-event3-dmc1_0";
>> +			};
>> +		};
>> +	};
>> +
>> +	ppmu_dmc1_1: ppmu@10d70000 {
>> +		compatible = "samsung,exynos-ppmu";
>> +		reg = <0x10d70000 0x2000>;
>> +		clocks = <&clock CLK_PCLK_PPMU_DREX1_1>;
>> +		clock-names = "ppmu";
>> +		status = "okay";
>> +		events {
>> +			ppmu_event_dmc1_1: ppmu-event3-dmc1_1 {
>> +				event-name = "ppmu-event3-dmc1_1";
>> +			};
>> +		};
>> +	};
>> +
>> +	dmc: memory-controller@10c20000 {
>> +		compatible = "samsung,exynos5422-dmc";
>> +		reg = <0x10c20000 0x10000>, <0x10c30000 0x10000>,
>> +			<0x10000000 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 CLK_CDREX_PAUSE>,
>> +				<&clock CLK_CDREX_TIMING_SET>;
>> +		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",
>> +			        "clk_cdrex_pause",
>> +			        "clk_cdrex_timing_set";
>> +		status = "okay";
>> +		operating-points-v2 = <&dmc_opp_table>;
>> +		devfreq-events = <&ppmu_dmc0_0>, <&ppmu_dmc0_1>,
>> +				<&ppmu_dmc1_0>, <&ppmu_dmc1_1>;
>> +	};
>> +
>> +The needed timings of DRAM memory are stored in dedicated nodes.
>> +There are two nodes with regular timings and for bypass mode.
>> +
>> +	dmc_bypass_mode: bypass_mode {
>> +		compatible = "samsung,dmc-bypass-mode";
>> +
>> +		freq-hz = <400000000>;
>> +		volt-uv = <887500>;
>> +		dram-timing-row = <0x365a9713>;
>> +		dram-timing-data = <0x4740085e>;
>> +		dram-timing-power = <0x543a0446>;
>> +	};
>> +
>> +	dram_timing: timing {
>> +		compatible = "samsung,dram-timing";
>> +
>> +		dram-timing-names = "165MHz", "206MHz", "275MHz", "413MHz",
>> +				    "543MHz", "633MHz", "728MHz", "825MHz";
>> +		dram-timing-row = <0x11223185>, <0x112331C6>, <0x12244287>,
>> +				  <0x1B35538A>, <0x244764CD>, <0x2A48758F>,
>> +				  <0x30598651>, <0x365A9713>;
>> +		dram-timing-data = <0x2720085E>, <0x2720085E>, <0x2720085E>,
>> +				   <0x2720085E>, <0x3730085E>, <0x3730085E>,
>> +				   <0x3730085E>, <0x4740085E>;
>> +		dram-timing-power = <0x140C0225>, <0x180F0225>, <0x1C140225>,
>> +				    <0x2C1D0225>, <0x38270335>, <0x402D0335>,
>> +				    <0x4C330336>, <0x543A0446>;
>> +	};
>> +
>> +The frequencies supported by the DMC are stored in OPP table v2.
>> +
>> +	dmc_opp_table: opp_table2 {
>> +		compatible = "operating-points-v2";
>> +
>> +		opp00 {
>> +			opp-hz = /bits/ 64 <165000000>;
>> +			opp-microvolt = <875000>;
>> +		};
>> +		opp01 {
>> +			opp-hz = /bits/ 64 <206000000>;
>> +			opp-microvolt = <875000>;
>> +		};
>> +		opp02 {
>> +			opp-hz = /bits/ 64 <275000000>;
>> +			opp-microvolt = <875000>;
>> +		};
>> +		opp03 {
>> +			opp-hz = /bits/ 64 <413000000>;
>> +			opp-microvolt = <887500>;
>> +		};
>> +		opp04 {
>> +			opp-hz = /bits/ 64 <543000000>;
>> +			opp-microvolt = <937500>;
>> +		};
>> +		opp05 {
>> +			opp-hz = /bits/ 64 <633000000>;
>> +			opp-microvolt = <1012500>;
>> +		};
>> +		opp06 {
>> +			opp-hz = /bits/ 64 <728000000>;
>> +			opp-microvolt = <1037500>;
>> +		};
>> +		opp07 {
>> +			opp-hz = /bits/ 64 <825000000>;
>> +			opp-microvolt = <1050000>;
>> +		};
>> +	};
>> +
>>
> 
>