STPMIC25A settings for DDR configuration

[_Vanshika]

Hii, 
I am using STPMIC25A with STM32mp257FAK3 with DDR3L in one custom design and LPDDR4 in second custom design.

I am able to change o/p of Buck 4, Buck 6 and LDO 3 as per the requirement by changing the voltage for the same in the device tree, under fdts in Arm Trusted Firmware. I am sharing the node below:

&i2c7 {

pinctrl-names = "default";

pinctrl-0 = <&i2c7_pins_a>;

i2c-scl-rising-time-ns = <185>;

i2c-scl-falling-time-ns = <20>;

clock-frequency = <400000>;

status = "okay";

#address-cells = <1>;

#size-cells = <0>;

pmic2: stpmic@33 {

compatible = "st,stpmic2";

reg = <0x33>;

status = "okay";

regulators {

compatible = "st,stpmic2-regulators";

vddcpu: buck1 {

regulator-name = "vddcpu";

regulator-min-microvolt = <800000>;

regulator-max-microvolt = <910000>;

regulator-always-on;

};

vddcore: buck2 {

regulator-name = "vddcore";

regulator-min-microvolt = <820000>;

regulator-max-microvolt = <820000>;

regulator-always-on;

};

vddgpu: buck3 {

regulator-name = "vddgpu";

regulator-min-microvolt = <800000>;

regulator-max-microvolt = <900000>;

regulator-always-on;

};

vddio_pmic: buck4 {

regulator-name = "vddio_pmic";

regulator-min-microvolt = <3300000>;

regulator-max-microvolt = <3300000>;

regulator-always-on;

};

v1v8: buck5 {

regulator-name = "v1v8";

regulator-min-microvolt = <1800000>;

regulator-max-microvolt = <1800000>;

regulator-always-on;

};

vdd2_ddr: buck6 {

regulator-name = "vdd2_ddr";

regulator-min-microvolt = <1100000>;

regulator-max-microvolt = <1100000>;

};

v3v3: buck7 {

regulator-name = "v3v3";

regulator-min-microvolt = <3300000>;

regulator-max-microvolt = <3300000>;

regulator-always-on;

};

vdda1v8_aon: ldo1 {

regulator-name = "vdda1v8_aon";

regulator-min-microvolt = <1800000>;

regulator-max-microvolt = <1800000>;

regulator-always-on;

};

vdd_emmc: ldo2 {

regulator-name = "vdd_emmc";

regulator-min-microvolt = <3300000>;

regulator-max-microvolt = <3300000>;

regulator-always-on;

};

vdd1_ddr: ldo3 {

regulator-name = "vdd1_ddr";

regulator-min-microvolt = <1800000>;

regulator-max-microvolt = <1800000>;

};

vdd3v3_usb: ldo4 {

regulator-name = "vdd3v3_usb";

regulator-min-microvolt = <3300000>;

regulator-max-microvolt = <3300000>;

regulator-always-on;

};

v5v_hdmi: ldo5 {

regulator-name = "v5v_hdmi";

regulator-min-microvolt = <2000000>;

regulator-max-microvolt = <2000000>;

};

vdd_sdcard: ldo7 {

regulator-name = "vdd_sdcard";

regulator-min-microvolt = <3300000>;

regulator-max-microvolt = <3300000>;

regulator-always-on;

};

vddio_sdcard: ldo8 {

regulator-name = "vddio_sdcard";

st,regulator-bypass-microvolt = <3300000>;

regulator-min-microvolt = <1800000>;

regulator-max-microvolt = <3300000>;

regulator-always-on;

};

};

};

};

Please confirm are there any other changes required for proper operation.

[ThomasB]

Hello @_Vanshika,

Regarding the power supply part, you also need to update similarly the PMIC node in OP-TEE.

Each design will also need its own set of DDR settings that correspond to the required configuration. You will need a DTSI settings file for each design in TF-A, which must be included by the top DTS file for each design. These settings files can be generated by CubeMX and there are also examples in the TF-A source code (with names like "stm32mp25-lpddr4-1x32bits-1200MHz.dtsi" for example).

Depending on the design you may also use different memory sizes, that you will need to adapt the node memory in each component (U-Boot, TF-A, OP-TEE, Linux). You can find help on this matter in this wiki page: https://wiki.st.com/stm32mpu/wiki/How_to_setup_the_DDR_configuration#STM32MP2_series.

I hope this will helps you enough to make your designs work.

Best regards,

Thomas