Re: [PATCH v4 03/12] dt-bindings: clock: renesas,r9a08g045-vbattb: Document VBATTB

[Claudiu Beznea <claudiu.beznea@tuxon.dev>]

On 21.10.2024 10:34, Krzysztof Kozlowski wrote:
> On Mon, Oct 21, 2024 at 09:32:37AM +0200, Krzysztof Kozlowski wrote:
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    #include <dt-bindings/clock/r9a08g045-cpg.h>
>>> +    #include <dt-bindings/clock/renesas,r9a08g045-vbattb.h>
>>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>>> +    #include <dt-bindings/interrupt-controller/irq.h>
>>> +
>>> +    clock-controller@1005c000 {
>>> +        compatible = "renesas,r9a08g045-vbattb";
>>> +        reg = <0x1005c000 0x1000>;
>>> +        interrupts = <GIC_SPI 43 IRQ_TYPE_LEVEL_HIGH>;
>>> +        clocks = <&cpg CPG_MOD R9A08G045_VBAT_BCLK>, <&vbattb_xtal>;
>>> +        clock-names = "bclk", "rtx";
>>> +        assigned-clocks = <&vbattb VBATTB_MUX>;
>>> +        assigned-clock-parents = <&vbattb VBATTB_XC>;
>>
>> Why are you configuring internal clocks to internal parents? That's part
>> internal to this device, not DTS... or at least some explanation would
>> be useful.
> 
> From DTS I see this belongs to the board, not SoC, so makes sense.

That's true. This configuration depends on the type of the input clock
connected to the RTXIN, RTXOUT pins which is board specific (see below
diagram):

           +----------+ XC   `\
RTXIN  --->|          |----->| \       +----+  VBATTCLK
           | 32K clock|      |  |----->|gate|----------->
	   | osc      | XBYP |  |      +----+
RTXOUT --->|          |----->| /
           +----------+      ,/

Thank you,
Claudiu Beznea

> 
> Best regards,
> Krzysztof
>