DDR clock frequency scaling not supported with newer linux kernel (5.15+)

[gfkjfgt]

Hi, we have a custom board based on IMX8MM. We were looking at the application note: AN12410 (i.MX8M Mini Power consumption measurement) where it describes the IDLE_DDRC_25MHz mode as a way to save power. However the ddrc nodes has been removed from the imx8mm.dtsi device tree here: https://github.com/nxp-imx/linux-imx/commit/2a6b87ca632bce18e519e7b6ce81c5bda89cad0e .

Is it not supported anymore to clock down the memory frequency?

What do you suggest to use instead?

Regards

 

 

[Sanket_Parekh]

Hi @gfkjfgt 

I hope you are doing well.

What do you suggest to use instead?

=> Yes, In the latest commit the interconnect and ddrc nodes have been removed as described in the link. To save power one can try to use the CCM Clock Gating Register (CCGR) mentioned in the IMX8MMRM.

Kindly refer to section 5.1.6.3 CCGR Interface for more information.

Thanks & Regards,

Sanket Parekh