Hi Krystoff, > Subject: Re: [PATCH RFC 4/6] dt-bindings: rtc: isl1208: Document built-in > RTC device on PMIC RAA215300 > > On 04/05/2023 09:47, Geert Uytterhoeven wrote: > > Hi Krzysztof, > > > > On Thu, May 4, 2023 at 9:11 AM Krzysztof Kozlowski > > <krzysztof.kozlowski@xxxxxxxxxx> wrote: > >> On 03/05/2023 10:46, Biju Das wrote: > >>> The Built-in RTC device found on PMIC RAA215300 is similar to the > >>> isl1208 IP. However, RTC is enabled by PMIC RAA215300 and the > >>> polarity of the external oscillator is determined by the PMIC revision. > >>> > >>> Document renesas,raa215300-isl1208 compatible and > >>> renesas,raa215300-pmic property to handle these differences. > >>> > >>> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx> > >>> --- > >>> .../devicetree/bindings/rtc/isil,isl1208.yaml | 13 +++++++++++++ > >>> 1 file changed, 13 insertions(+) > >>> > >>> diff --git a/Documentation/devicetree/bindings/rtc/isil,isl1208.yaml > >>> b/Documentation/devicetree/bindings/rtc/isil,isl1208.yaml > >>> index 04d51887855f..888a832ed1db 100644 > >>> --- a/Documentation/devicetree/bindings/rtc/isil,isl1208.yaml > >>> +++ b/Documentation/devicetree/bindings/rtc/isil,isl1208.yaml > >>> @@ -18,6 +18,7 @@ properties: > >>> - isil,isl1209 > >>> - isil,isl1218 > >>> - isil,isl1219 > >>> + - renesas,raa215300-isl1208 > >>> > >>> reg: > >>> maxItems: 1 > >>> @@ -40,6 +41,10 @@ properties: > >>> <0> : Enable internal pull-up > >>> <1> : Disable internal pull-up > >>> > >>> + renesas,raa215300-pmic: > >>> + $ref: /schemas/types.yaml#/definitions/phandle > >>> + description: phandle to the pmic device with isl1208 built-in RTC. > >> > >> No. You don't need cross-linking. We do not represent one device as > >> two and then fix this by cross-linking them. The existing binding > >> does not have it, so it should be a hint for you. > > > > Makes sense. > > So there should be a single device node with 2 reg cells, and a > > "renesas,raa215300" compatible value. > > Yes. > > > > > On the Linux side, the "renesas,raa215300" MFD driver can instantiate > > a PMIC and an RTC cell, the latter served by the (enhanced) existing > > rtc-isl1208 driver. > > Right. We cannot use MFD driver to instantiate RTC as it is not platform device. Thanks to Geert for pointing out "i2c_new_ancillary_device". With this, we can register rtc device from pmic driver Using the api "raa215300_rtc_probe(struct i2c_client *client, unsigned int pmic_version)". Cheers, Biju