soc: rockchip: io-domain: add rk3568 support

soc: rockchip: io-domain: add rk3568 support

The io-domain registers on RK3568 SoCs have three separated bits to
enable/disable the 1.8v/2.5v/3.3v power.

This patch make the write to be a operation, allow rk3568 uses a private
register set function.

Since the 2.5v mode hasn't been fully validated yet, the driver only sets
1.8v [enable] + 3.3v [disable] for 1.8v mode
1.8v [disable] + 3.3v [enable] for 3.3v mode

There is not register order requirement which has been cleared by our IC
team.

For future reference the full usage matrix including the 2.5V setting is:
case  V33  V25  V18  result
0     0    0    0    IO safe, but cannot work
1     0    0    1    IO require 1.8V, should < 1.98V, otherwise IO may damage
2     0    1    0    IO require 2.5V, should < 2.75V, otherwise IO may damage
3     0    1    1    Invalid state, should avoid
4     1    0    0    IO require 3.3V, should < 3.63V, otherwise IO may damage
5     1    0    1    IO require 1.8V, should < 1.98V, otherwise IO may damage
6     1    1    0    IO require 2.5V, should < 2.75V, otherwise IO may damage
7     1    1    1    Invalid state, should avoid

Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>
Tested-by: Peter Geis <pgwipeout@gmail.com>
[added mode clarification from Jay]
Link: https://lore.kernel.org/r/20210805120107.27007-3-michael.riesch@wolfvision.net
Signed-off-by: Heiko Stuebner <heiko@sntech.de>