Re: [PATCH 1/3] dt-bindings: rtc: Add Raspberry Pi 5 RTC binding

[Sander Speetjens <sander.speetjens@gmail.com>]

 > And more important, where is any interface to actually control the RTC?
 > I see nothing, so your firmware is? Then this is not a separate device
 > and you just added DTS for your driver, which is a no go (see writing
 > bindings).

The RTC is a physical, battery-backed RTC, but the Raspberry Pi
firmware exposes its register interface exclusively through the
firmware mailbox.

I initially used a firmware phandle so that the RTC driver could obtain
the existing rpi_firmware instance.

Based on your comment, I think it would be more appropriate to model
the RTC as a child device of rpi-firmware. The driver could then obtain
the firmware interface from its parent, rather than adding a phandle
solely for driver plumbing.

This would also mean moving the binding to
arm/bcm/raspberrypi,bcm2835-firmware.yaml.

Best regards,
Sander

On 9/9/26 17:54, Krzysztof Kozlowski wrote:
> On 09/09/2026 17:47, Krzysztof Kozlowski wrote:
>> On 09/09/2026 16:12, Sander Speetjens wrote:
>>> +
>>> +  firmware:
>> There is no such generic property. You need vendor prefix. Wasn't this
>> already discussed for Rpi? I feel like every time contributors send
>> downstream DTS ignoring what was discussed upstream.
>>
>>
>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>> +    description:
>>> +      Phandle to the Raspberry Pi firmware device.
>> You said nothing more than property name and type. Explain what for.
>>
> And more important, where is any interface to actually control the RTC?
> I see nothing, so your firmware is? Then this is not a separate device
> and you just added DTS for your driver, which is a no go (see writing
> bindings).
>
> Best regards,
> Krzysztof