On Mon 29 Feb 06:40 PST 2016, Laxman Dewangan wrote: > It is observed that voltage change in given rail affected by the load > and the capacitor in the rail. This may cause the slow ramp in voltage > against what PMIC has programmed. > > The property regulator-ramp-delay provides the ramp delay configuration > for PMIC but actual voltage settling time may change based on platform. > > Add new property "regulator-ramp-delay-scale" for platform specific scaling > in final ramp delay calculation. On this case, final wait delay time > for voltage change is calculated as the > DIV_ROUND_UP(ramp_delay * ramp_delay_scale, 100) > > The value is provided in the term of percentage i.e. 300% means it will > do the 3x delay of calculated value. > > Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx> > --- The regulator-ramp-delay is a variable you can tweak on a board basis, so I'm not sure what benefit it gives to be able to add a scaling factor to this. In my experience your HW engineer will say "you have to wait X ms", not "you have to wait 125% of X ms". Can you please elaborate on why the original knob isn't sufficient? Regards, Bjorn > Documentation/devicetree/bindings/regulator/regulator.txt | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/devicetree/bindings/regulator/regulator.txt b/Documentation/devicetree/bindings/regulator/regulator.txt > index 1d112fc..f2e8360 100644 > --- a/Documentation/devicetree/bindings/regulator/regulator.txt > +++ b/Documentation/devicetree/bindings/regulator/regulator.txt > @@ -16,6 +16,13 @@ Optional properties: > - regulator-ramp-delay: ramp delay for regulator(in uV/uS) > For hardware which supports disabling ramp rate, it should be explicitly > initialised to zero (regulator-ramp-delay = <0>) for disabling ramp delay. > +- regulator-ramp-delay-scale: Platform specific scaling in ramp delay to > + provide extra guard time to settle down voltage after its change. This will > + help to wait for extra time for voltage settling based on platform behavior. > + This is provided in terms of percentage scaling like 300% means final delay > + will become 3x of calculated ramp delay for voltage change. > + The final delay is calculated as: > + delay = DIV_ROUND_UP(ramp-delay * ramp-delay-scale, 100) > - regulator-enable-ramp-delay: The time taken, in microseconds, for the supply > rail to reach the target voltage, plus/minus whatever tolerance the board > design requires. This property describes the total system ramp time > -- > 2.1.4 > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
