linux-imx

MLK-22404-02 soc: imx: Add power domain driver support for i.mx8m family

The i.MX8M family is a set of NXP product focus on delivering
the latest and greatest video and audio experience combining
state-of-the-art media-specific features with high-performance
processing while optimized for lowest power consumption.

i.MX8MQ, i.MX8MM, i.MX8MN, even the furture i.MX8MP are all
belong to this family. A GPC module is used to manage all the
PU power domain on/off. But the situation is that the number of
power domains & the power up sequence has significate difference
on those SoCs. Even on the same SoC. The power up sequence still
has big difference. It makes us hard to reuse the GPCv2 driver to
cover the whole i.MX8M family. Each time a new SoC is supported in
the mainline kernel, we need to modify the GPCv2 driver to support
it. We need to add or modify hundred lines of code in worst case.
It is a bad practice for the driver maintainability.

This driver add a more generic power domain driver that the actual
power on/off is done by TF-A code. the abstraction give us the
possibility that using one driver to cover the whole i.MX8M family
in kernel side.

Signed-off-by: Jacky Bai <ping.bai@nxp.com>