Hi Geert, > Subject: RE: [PATCH v3 3/5] dt-bindings: mfd: Add Renesas RAA215300 PMIC > bindings > > Hi Geert, > > Thanks for the feedback. > > > -----Original Message----- > > From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> > > Sent: Tuesday, May 16, 2023 9:00 AM > > To: Biju Das <biju.das.jz@xxxxxxxxxxxxxx> > > Cc: Lee Jones <lee@xxxxxxxxxx>; Rob Herring <robh+dt@xxxxxxxxxx>; > > Krzysztof Kozlowski <krzysztof.kozlowski+dt@xxxxxxxxxx>; Magnus Damm > > <magnus.damm@xxxxxxxxx>; devicetree@xxxxxxxxxxxxxxx; linux-renesas- > > soc@xxxxxxxxxxxxxxx; Fabrizio Castro <fabrizio.castro.jz@xxxxxxxxxxx> > > Subject: Re: [PATCH v3 3/5] dt-bindings: mfd: Add Renesas RAA215300 > > PMIC bindings > > > > Hi Biju, > > > > On Sat, May 13, 2023 at 6:52 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> > > wrote: > > > > > > Document Renesas RAA215300 PMIC bindings. > > > > > > The RAA215300 is a high Performance 9-Channel PMIC supporting DDR > > > Memory, with Built-In Charger and RTC. > > > > > > It supports DDR3, DDR3L, DDR4, and LPDDR4 memory power requirements. > > > The internally compensated regulators, built-in Real-Time Clock > > > (RTC), 32kHz crystal oscillator, and coin cell battery charger > > > provide a highly integrated, small footprint power solution ideal > > > for System-On-Module (SOM) applications. A spread spectrum feature > > > provides an ease-of-use solution for noise-sensitive audio or RF > > > applications. > > > > > > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx> > > > --- > > > v2->v3: > > > * Added more detailed description for renesas,rtc-enabled property. > > > > Thanks for your patch! > > > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/mfd/renesas,raa215300.yaml > > > > > + renesas,rtc-enabled: > > > + description: > > > + To indicate RTC is enabled on the PMIC. > > > + Enabling of the RTC is based on system design. System > > > + designers > > may > > > + choose not to populate built-in RTC by grounding XIN and XOUT > > pins. > > > + type: boolean > > > > Perhaps you should go full DT monty and replace this logic by a clocks > > property pointing to the external crystal? > > OK for me. Krzysztof Kozlowski, Rob are you ok with this? > > > > > However, as I only have the Short-Form Datasheet, I am wondering what > > "Built-in 32kHz crystal oscillator (with bypass)" really means? > > It is not mentioned in original doc as well. > > > Does this mean the RTC can work without an external crystal, using an > > on-chip oscillator? > > I am checking with hardware team. I will update you once I get this > info. Please find the answer from HW team, it is inline with current implementation. Q1) Can you please clarify "Built-in 32kHz crystal oscillator (with bypass)" really means? Ans: The RTC on RAA215300 can work with an external 32.768kHz crystal or an external clock IC. So you can use it in two different ways: 1) Connect an external 32.768kHz crystal to XIN/XOUT. The on-chip oscillator needs to be enabled in this case, meaning the XTOSCB bit(0x07[6]) needs to be at ‘0’ (default value). 2) Connect an external clock IC of 32.768kHz to the XIN pin. The on-chip oscillator needs to be disabled (bypassed) in this case, meaning the XTOSCB bit needs to be at ‘1’. Q2) Does this mean the RTC can work without an external crystal, using an on-chip oscillator? Ans: I guess you meant using the on-chip oscillator only without connecting anything to XIN/XOUT. That is not possible. Cheers, Biju
