[U-Boot] [U-Boot,v5,1/3] power: add FAN53555 family support

[Philipp Tomsich]

> This adds a driver for the FAN53555 family of regulators and wraps it
> in a PMIC implementation.
> 
> While these devices support a 'normal' and 'suspend' mode (controlled
> via an external pin) to switch between two programmable voltages, this
> incarnation of the driver assumes that the device is always operating
> in 'normal' mode.
> 
> Only setting/reading the programmed voltage is supported at this time
> and the following device functionality remains unsupported:
>   - switching the selected voltage (via a GPIO)
>   - disabling the voltage output via software-control
> This matches the functionality of the Linux driver.
> 
> Tested on a RK3399-Q7 (with 'option 5' devices): setting voltages from
> the U-Boot shell and verifying output voltages on the board.
> 
> Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>
> Tested-by: Klaus Goger <klaus.goger at theobroma-systems.com>
> ---
> 
> Changes in v5:
> - introduced a PMIC (as requested by SJG) to wrap the single regulator
> 
> Changes in v4:
> - fix issues introduced when updating for review comments (sorry for
>   this: my submit-branch had diverged from the WIP-branch I used for
>   testing and I didn't notice)
> 
> Changes in v3:
> - update for review comments
> 
> Changes in v2:
> - adapted documentation on the device-tree binding from Linux
> 
>  doc/device-tree-bindings/regulator/fan53555.txt |  23 +++
>  drivers/power/pmic/Kconfig                      |  14 ++
>  drivers/power/pmic/Makefile                     |   1 +
>  drivers/power/pmic/fan53555.c                   |  82 +++++++++
>  drivers/power/regulator/Kconfig                 |  16 ++
>  drivers/power/regulator/Makefile                |   1 +
>  drivers/power/regulator/fan53555.c              | 222 ++++++++++++++++++++++++
>  7 files changed, 359 insertions(+)
>  create mode 100644 doc/device-tree-bindings/regulator/fan53555.txt
>  create mode 100644 drivers/power/pmic/fan53555.c
>  create mode 100644 drivers/power/regulator/fan53555.c
> 

Applied to u-boot-rockchip, thanks!