Messages in this thread | | | Date | Fri, 16 Dec 2022 08:28:26 +0100 | Subject | Re: [PATCH v7 1/6] DONOTMERGE: arm64: dts: ti: Add TI TPS65219 PMIC support for AM642 SK board. | From | jerome Neanne <> |
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On 16/12/2022 07:21, Vignesh Raghavendra wrote: > > > On 16/12/22 03:11, Nishanth Menon wrote: >> On 18:22-20221215, Mark Brown wrote: >>> On Thu, Dec 15, 2022 at 11:54:11AM -0600, Nishanth Menon wrote: >>>> On 16:09-20221215, Mark Brown wrote: >>> >>>>> That proposal looks really non-idiomatic and quite unusual, if there's a >>>>> fixed voltage supply to the LDO I'd expect to see it modeled as a fixed >>>>> voltage regulator. I'm not sure what the use of bypass here is trying >>>>> to accomplish TBH. >>> >>>> The problem is this - the default NVM in the PMIC is setup such that >>>> VSET value =3.3v and bypass bit set (makes sense since the vin=3.3v). >>> >>> This implies no voltage drop over the LDO? Sounds a bit suspect. >> >> Not the choice I'd probably have made ;) >> >>> >>>> Now the constraint is bypass bit cannot be changed without the LDO >>>> being switched off. >>> > > Per https://www.ti.com/lit/ds/symlink/tps65219.pdf (7.3.6 Linear > Regulators). > > LDOs have two modes: > > 1. Load switch mode: in this case, output voltages of 1.5V up to 5.5V > are supported. > > 2 Linear regulator LDO mode where output voltage is programmable in the > range of 0.6V to 3.4V in 50mV-steps with possibility of bypass. > > (CAUTION on page 25): > A mode change between LDO(/bypass) and LSW-mode must only be performed, > when this regulator is disabled! > A change between LDO and bypass-mode (supported by LDO1 and LDO2 only) > is supported during operation. > > So, seems like bypass can be toggled even with LDO on? >I possibly miss-interpreted this caution statement which leads to that situation.
Your understanding sounds correct. My mistake... Sorry for that
Regards, Jerome.
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