Messages in this thread | | | Date | Wed, 14 Jul 2010 19:42:51 +0100 | From | Mark Brown <> | Subject | Re: [PATCH v2 2/2] ux500: add ab8500-regulators machine specific data |
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On Wed, Jul 14, 2010 at 11:06:51PM +0530, Sundar R IYER wrote:
> > OK, but your current set of supplies is *very* suspect since you're > > offering all this control to lists of consumers that don't exist, and
> As said, dont exist for *now*.
This comes back to my point about the control only making sense when the consumers are present - if you've got missing or partial consumer setup done then control is questionable.
> Probably, I should remove the REGULATOR_CHANGE_VOLTAGE flag for the fixed > supplies (as in the driver) to clear up any confusing link. Should I?
Yes.
> > This is normal, but for fairly obvious reasons the very lowest power > > states are generally handled outside of the regulator API at a hardware > > level via hardware signals to the regulator. It's not normally part of > > the runtime constraints for use while the CPU is live.
> Yes. But my point was that even at a lower level than kernel (BIOS/firmware?) > the switching would happen via SW. Please correct me if I am wrong!
Well, ultimately it's always triggered by software but the actual signal to the regulator is often a logic level output by the SoC as the processor enters a low power state rather than an I2C/SPI write.
> > I'm not sure how you expect this to actually work in practice? It's > > going to be pretty hard for a driver to do anything constructive if the > > power to the hardware gets cut, for example. Unless you can guarantee > > that there will never be any use of the hardware without a driver with > > regulator support one driver's idea of optimal may not join up with what > > the other consumers need at all.
> Very true. But, I think this will *enforce* drivers using/sharing > regulators to adhere to the framework to avoid surprises and sole-owner > misuses, which is good, now that the AB8500 regulators *are* supported.
If you think your users will be sympathetic to this approach then I guess... obviously, it does have the potential to go rather badly wrong especially if there are some drivers without regulator support out there.
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