[U-Boot] [PATCH v3 6/9] regulator: Add support for ramp delay

[Torsten Duwe]

On Sat, Feb 16, 2019 at 10:45:45AM +0100, Krzysztof Kozlowski wrote:
> Changing voltage and enabling regulator might require delays so the
> regulator stabilizes at expected level.
> 
> Add support for "regulator-ramp-delay" binding which can introduce
> required time to both enabling the regulator and to changing the
> voltage.

I'm surprised that such a thing doesn't exist already.

> Signed-off-by: Krzysztof Kozlowski <krzk at kernel.org>

> --- a/doc/device-tree-bindings/regulator/regulator.txt
> +++ b/doc/device-tree-bindings/regulator/regulator.txt
> @@ -35,6 +35,7 @@ Optional properties:
>  - regulator-max-microamp: a maximum allowed Current value
>  - regulator-always-on: regulator should never be disabled
>  - regulator-boot-on: enabled by bootloader/firmware
> +- regulator-ramp-delay: ramp delay for regulator (in uV/us)

I guess you mean s/V, not V/s; at least the code suggests so.
But my main point is: is the required delay always a linear
function of the voltage jump? Depending on the dampening and
load on the rail this could be an overshoot and settle, no?

So I suggest to make that an array with 2 elements: a fixed part
and a time per voltage change. Does that make sense?

	Torsten