> Mark Brown <broonie@xxxxxxxxxx> hat am 27. Mai 2015 um 19:33 geschrieben: > > > On Tue, May 26, 2015 at 02:16:55PM +0200, Stefan Wahren wrote: > > > Mark Brown <broonie@xxxxxxxxxx> hat am 7. Mai 2015 um 21:32 geschrieben: > > > > > > > In the bootloader code enabling the DC-DC is critical. There is a > > > > > > known > > > > > > issue > > > > > > which falsely triggers the brownout detection. > > > > > > Why would the driver not provide these operations? > > > > > I didn't implement this operation because the suggested workaround for > > > > the > > > > hardware issue isn't very nice > > > > (disable brownout detection during enabling DC-DC). I was afraid of the > > > > implementation. > > > > That doesn't sound too complicated? > > > Okay, i think i managed the brownout handling. > > > > Unfortunately i'm stuck at the next step. The DC-DC (3 way output) can > > supply 3 > > LDOs vddd, vdda, vddio. In case of a DC-DC state change the 3 regulators > > needs > > to be reconfigured before. > > > I tought of REGULATOR_EVENT_PRE_DISABLE and REGULATOR_EVENT_PRE_ENABLE > > events, > > but i'm not sure that's the right way to achieve a synchronization between > > DC-DC > > and consuming LDOs. > > OK, that's possibly sounding a bit complicated. Is it just a case of > writing some value, doing a reconfiguration and rewriting the original > value or is it something more? In case of a single driver instance instead of 4 ones (vddd, vddio, vdda, dc-dc), things would be much easier. Here are the steps for disabling DC-DC: 1. configure vddio to work without DC-DC 2. configure vdda to work without DC-DC 3. configure vddd to work without DC-DC 4. backup DC-DC settings 5. disable brownout detection 6. disable DC-DC 7. restore DC-DC settings My problem is that step 1 to 3 must be done step by step through the other regulator instances. > If it's much more complicated than that > then I think putting a comment in the driver explaining what the issue > is would be the right step, that would address the issue with the driver > looking strange. Enabling or disabling DC-DC is only needed internally by the power subsystem (e.g. in case of handoff AC to battery), because the DC-DC only supplys the regulator daisy. From my understanding hardware components could use only the regulator outputs. In the end a state change is necessary, but it shouldn't be a public. -- 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
