AM62L-PROCESSOR-SDK: Query Regarding PMIC Configuration in AM62L source

Hello,

Just to start, here a few application notes discussing the TPS65214 which is the companion PMIC for the AM62L processor:

• AM62L Power Supply Information: https://www.ti.com/lit/an/slvafw3/slvafw3.pdf
• TPS65214 Datasheet: https://www.ti.com/lit/ds/slvshk7/slvshk7.pdf
• TPS65214 TRM: https://www.ti.com/lit/ug/slvud30/slvud30.pdf

Dheeraj K said:

do not see any PMIC-related references in the U-Boot source or the kernel device tree.

Correct, so the PMIC is not added to the device trees since it is not required to configure the PMIC. If it needs to be used, it will re-use the drivers for TPS65219: https://git.ti.com/cgit/ti-linux-kernel/ti-linux-kernel/tree/Documentation/devicetree/bindings/regulator/ti,tps65219.yaml?h=ti-linux-6.12.y

PMIC Linux drivers are typically used to interact with the PMIC after booting and capture an interrupt generated by the PMIC.

Dheeraj K said:

If the PMIC is not explicitly configured in U-Boot or the kernel, how does the system manage power sequencing?

In short, the PMIC has internal memory that is pre-programmed with information to start the power-up sequence. Once the power is supplied to the PMIC (or a signal from the SoC is given), the PMIC reads the internal memory and loads various registers.

This allows for the processor to boot up independent of operating system (or baremetal). I recommend you review the documents I linked above to get a deeper look at the PMIC's inter-workings.

Dheeraj K said:

Furthermore, for a custom board using a different PMIC, where should modifications be made to integrate the new PMIC properly?

Which PMIC are you planning to use besides TPS65214? If its another TI part, I can loop in the PMIC team to review the possibilities. 

Best Regards,

Anshu

Hello Anshu ,

Thank you for the details regarding the PMIC. Once our hardware team finalizes the PMIC selection, I will reach out if any further information is needed.

Hello Anshu,

Since you mentioned that the Linux driver will be detected automatically if required, I have one question: Without any specific configuration, how does the system determine which driver to use in the absence of a compatible property? Additionally, if I need to change the voltage supply of the PMIC (TPS65215), what modifications are required, and where should they be made?

Thanks,
Dheeraj

Hello Dheeraj,

Dheeraj K said:

Since you mentioned that the Linux driver will be detected automatically if required,

The driver won't be automatically detected. It will need to be added in the Linux Kernel Image/modules, then the device tree will need to be configured (including the compatible paramter) to add the PMIC information so the Linux Kernel can see it.

Just a reminder, the PMIC Linux driver isn't required for booting up the processor. Its normally used to configure the PMIC after boot or to catch interrupts generated by the PMIC.

Dheeraj K said:

Additionally, if I need to change the voltage supply of the PMIC (TPS65215), what modifications are required, and where should they be made?

Can you clarify what this means? Are you asking about the input supply voltage into the PMIC? Or is this regarding the LDOs/Bucks from the PMIC into the processor?

Thanks,

Anshu

Hello Anshu,

I need to configure my PMIC so that i can read and write the values just to confirm . And i have noticed that PMIC is under wkup_i2c0 which is disabled in evk . Could you please check my query regarding this in another thread where i have explained my needs and observation : https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1496866/am62l-processor-sdk-pmic-configuration .

Thanks
Dheeraj K

Hi Dheeraj,

I'm looking into it and will respond on the linked thread.

Thanks,

Anshu