Subject: [PATCH v6 6/8] Documentation: bindings: add dt documentation for rk3399 dmc

From: [email-masked] (Chanwoo Choi)
Date: Tue, 23 Aug 2016 14:05:43 +0900

Hi Lin,

On 2016? 08? 22? 07:16, hl wrote:
> Hi Chanwoo Choi,
> 
> On 2016?08?17? 12:50, Chanwoo Choi wrote:
>> Hi Lin,
>>
>> On 2016? 08? 17? 07:36, Lin Huang wrote:
>>> This patch adds the documentation for rockchip rk3399 dmc driver.
>>>
>>> Signed-off-by: Lin Huang <[email-masked]>
>>> ---
>>> Changes in v6:
>>> -Add more detail in Documentation
>>>
>>> Changes in v5:
>>> -None
>>>
>>> Changes in v4:
>>> -None
>>>
>>> Changes in v3:
>>> -None
>>>
>>> Changes in v2:
>>> -None
>>>
>>> Changes in v1:
>>> -None
>>>   .../devicetree/bindings/devfreq/rk3399_dmc.txt     | 84 ++++++++++++++++++++++
>>>   1 file changed, 84 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
>>> new file mode 100644
>>> index 0000000..e73067c
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/devfreq/rk3399_dmc.txt
>>> @@ -0,0 +1,84 @@
>>> +* 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-dif.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.
>> If possible, you better to keep the indentation with other properties.
>> s/it->It, dcf->DCF, ddr->DDR
>>
>>
>>> +- 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.
>> ditto.
>>
>>> +- center-supply: Dmc supply node.
>> s/Dmc/DMC becaue DMC an abbreviation.
>>
>>> +- status: Marks the node enabled/disabled.
>>> +
>>> +Optional properties:
>>> +- ddr_timing: ddr timing need to pass to arm trust firmware
>>> +- upthreshold: the upthreshold to simpleondeamnd policy
>>> +- downdifferential: The downdifferential to simpleondeamnd policy
>>> +
>>> +Example:
>>> +    ddr_timing: ddr_timing {
>>> +        compatible = "rockchip,ddr-timing";
>> I can't find the 'rockchip,ddr-timing' driver on linux-next git repo (20160816).
>> If ddr_timing includes the only properties for ddr_timing,
>> I recommend you make the separate a .dtsi file including
>> the ddr timing configuration. I add the reference and an example on below.
>>
>>> +        ddr3_speed_bin = <21>;
>>> +        pd_idle = <0>;
>>> +        sr_idle = <0>;
>>> +        sr_mc_gate_idle = <0>;
>>> +        srpd_lite_idle    = <0>;
>>> +        standby_idle = <0>;
>>> +        dram_dll_dis_freq = <300>;
>>> +        phy_dll_dis_freq = <125>;
>>> +
>>> +        ddr3_odt_dis_freq = <333>;
>>> +        ddr3_drv = <DDR3_DS_40ohm>;
>>> +        ddr3_odt = <DDR3_ODT_120ohm>;
>>> +        phy_ddr3_ca_drv = <PHY_DRV_ODT_40>;
>>> +        phy_ddr3_dq_drv = <PHY_DRV_ODT_40>;
>>> +        phy_ddr3_odt = <PHY_DRV_ODT_240>;
>>> +
>>> +        lpddr3_odt_dis_freq = <333>;
>>> +        lpddr3_drv = <LP3_DS_34ohm>;
>>> +        lpddr3_odt = <LP3_ODT_240ohm>;
>>> +        phy_lpddr3_ca_drv = <PHY_DRV_ODT_40>;
>>> +        phy_lpddr3_dq_drv = <PHY_DRV_ODT_40>;
>>> +        phy_lpddr3_odt = <PHY_DRV_ODT_240>;
>>> +
>>> +        lpddr4_odt_dis_freq = <333>;
>>> +        lpddr4_drv = <LP4_PDDS_60ohm>;
>>> +        lpddr4_dq_odt = <LP4_DQ_ODT_40ohm>;
>>> +        lpddr4_ca_odt = <LP4_CA_ODT_40ohm>;
>>> +        phy_lpddr4_ca_drv = <PHY_DRV_ODT_40>;
>>> +        phy_lpddr4_ck_cs_drv = <PHY_DRV_ODT_80>;
>>> +        phy_lpddr4_dq_drv = <PHY_DRV_ODT_80>;
>>> +        phy_lpddr4_odt = <PHY_DRV_ODT_60>;
>>> +    };
>>> +
>>> +    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";
>>> +        ddr_timing = <&ddr_timing>;
>> You can use the following '#include' instead of 'ddr_timing'
>> because the ddr_timing is not a device driver. Instead,
>> the rk3399-dmc must need the ddr timing configuration.
>>
>>         #include "rk3399-dmc-timing-conf.dtsi"
>>
>> You can refer the similar usage case[1].
>> The *.conf.dtsi is used on exynos3250 tmu dt node[2].
>>
>> [1] arch/arm/boot/dts/exynos4412-tmu-sensor-conf.dtsi
>> [2] arch/arm/boot/dts/exynos3250.dtsi, 224 line.
>>
>>> +        operating-points-v2 = <&dmc_opp_table>;
>>> +        center-supply = <&ppvar_centerlogic>;
>>> +        upthreshold = <15>;
>>> +        downdifferential = <10>;
>>> +        status = "disabled";
>>> +    };
>>> +
>>>
>> For example,
>> I think that you can add the following timing .dtsi file.
>> - arch/arm/boot/dts/rk3399-dmc-timing-conf.dtsi
>>
>> /*
>>   * Device tree sources for RK3399 DDR timing configuration
>>   *
>>   * Copyright (c) 2016 Lin Huang <[email-masked]>
>>   *
>>   * This program is free software; you can redistribute it and/or modify
>>   * it under the terms of the GNU General Public License version 2 as
>>   * published by the Free Software Foundation.
>>   */
>>
>> rockchip,ddr3_speed_bin = <21>;
>> rockchip,pd_idle = <0>;
>> rockchip,sr_idle = <0>;
>> rockchip,sr_mc_gate_idle = <0>;
>> rockchip,srpd_lite_idle    = <0>;
>> rockchip,standby_idle = <0>;
>> rockchip,dram_dll_dis_freq = <300>;
>> rockchip,phy_dll_dis_freq = <125>;
>>
>> 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>;
> Actually, i am doing like it on my downstream dtsi, but how to explain it in rk3399_dmc Documentation?
> Creat a new ddr_timing Documentation? But it is not a driver, just a dtsi, that why i put it on rk3399_dmc.txt
> now, do you have a better idea?

I think that you don't need to add the new ddr_timing document.

The ddr_timing value are only used in the rk3399_dmc.c driver.
So, the description of ddr_timing information should be
included in rk3399_dmc.txt.

As I already mentioned, please refer the the similiar case[1][2].
The exynos-thermal.txt[2] include the description of propertis[1].

[1] arch/arm/boot/dts/exynos4412-tmu-sensor-conf.dtsi
[2] Documentation/devicetree/bindings/tmu/exynos-thermal.txt
-- 
Best Regards,
Chanwoo Choi