On Thu, Jun 10, 2021 at 5:19 PM Val Kondratenko
Yes, imx7d is well supported in the mainline kernel.
I noticed (as I am attempting to apply patches we use), that /arch/arm/mach-imx/cpuidle-imx7d.c exists in the 5.4.X.imx version we are currently using, but is not present in 5.12. But mach-imx7d.c is.cpuidle is supported via PSCI implementation in U-Boot.
I suggest you to use U-Boot mainline too.