| Message ID | 20220803123332.8138-1-johan+linaro@kernel.org |
|---|---|
| Headers | show |
| Series | phy: qcom: drop regulator loads | expand |
Hi, On Wed, Aug 3, 2022 at 5:34 AM Johan Hovold <johan+linaro@kernel.org> wrote: > > Unless a driver implements an idle mode, there's generally no point in > specifying an active-mode regulator load. > > Drop the regulator loads that were recently added to the Qualcomm QMP > combo and edp PHY drivers. > > For a background discussion on this matter, see the following thread: > > https://lore.kernel.org/r/YuPps+cvVAMugWmy@sirena.org.uk > > Johan > > > Johan Hovold (2): > phy: qcom-qmp-combo: drop regulator loads > phy: qcom-edp: drop regulator loads > > drivers/phy/qualcomm/phy-qcom-edp.c | 12 ------- > drivers/phy/qualcomm/phy-qcom-qmp-combo.c | 40 +++++------------------ > 2 files changed, 9 insertions(+), 43 deletions(-) It's really hard to evaluate this based on the information I have available to me. :( I'm all for getting rid of all this complexity if it was added for no reason and I could definitely believe that on most boards there is no reason for it at all as talked about in other threads. I guess I worry that there is some use case where LPM mode is actually usable to power these devices when they're active. It seems like _maybe_ it could be but only if nothing else is pulling power from the same LDO? Some LDOs on the board I have seem to be able to do LPM up to 30 mA and some of the rails are being specified as ~22mA. The problem with regulator loads is that using them is kinda an "all or nothing". Either all the consumers need to specify something or none of them can. :( This means that once the first user comes in and is able to run the device in LPM (maybe only if they're the only consumer?) that everything will break. I honestly have no idea if this will ever happen, though... Mark said the phrase "actively managing loads it's probably not doing anything useful" and I think "probably" is an important word there. If that word was "never" then it would definitely be OK to remove load management like this, but with "probably" it becomes a lot harder. If we needed a hack, I'd somewhat prefer a hack that just bumps the "mA" value here up to something higher. That would force it to HPM... ...although maybe it still won't work? Then the regulator will still go down to LPM for other consumers if the PHY ever turns off. In that case I guess there's no getting around other consumers requesting the load or finding some way to say that on your board this regulator can only ever be in HPM mode. -Doug