Hi Doug,

On 05/30/2018 05:34 PM, Doug Anderson wrote:

On Wed, May 30, 2018 at 4:39 PM, David Collins [off-list ref] wrote:

quoted

Consider the case of a regulator with physical 10 mA LPM max current. Say
that modem and application processors each have a load on the regulator
that draws 9 mA. If they each respect the 10 mA limit, then they'd each
vote for LPM. The VRM block in RPMh hardware will aggregate these requests
together using a max function which will result in the regulator being set
to LPM, even though the total load is 18 mA (which would require high
power mode (HPM)). To get around this corner case, a LPM max current of 1
uA can be used for all LDO supplies that have non-application processor
consumers. Thus, any non-zero regulator_set_load() current request will
result in setting the regulator to HPM (which is always safe).

Is there any plan to change the way this works for future versions of RPMh?

As far as I know, no.  Adding VRM logic to sum RPMh client load current
requests, compare the sums to thresholds, select corresponding modes, and
override with explicit modes was determined to be too complex for RPMh.
Instead, much simpler max aggregation was implemented along with design
guidelines for PMICs to ensure that mode values are ordered from strictly
lower to higher power.

Take care,
David

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