linux-kernel - Re: [PATCH 03/12] dt-bindings: mfd: renesas,rzg3s-vbattb: Document VBATTB

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Date: Mon, 17 Jun 2024 10:16:22 +0300
From: claudiu beznea <claudiu.beznea@...on.dev>
To: Krzysztof Kozlowski <krzk@...nel.org>, geert+renesas@...der.be,
 mturquette@...libre.com, sboyd@...nel.org, robh@...nel.org,
 krzk+dt@...nel.org, conor+dt@...nel.org, lee@...nel.org,
 alexandre.belloni@...tlin.com, magnus.damm@...il.com
Cc: linux-renesas-soc@...r.kernel.org, linux-clk@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-rtc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
 Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: Re: [PATCH 03/12] dt-bindings: mfd: renesas,rzg3s-vbattb: Document
 VBATTB



On 16.06.2024 10:38, Krzysztof Kozlowski wrote:
> On 14/06/2024 09:19, Claudiu wrote:
>> From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
> 
>> +
>> +maintainers:
>> +  - Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
>> +
>> +properties:
>> +  compatible:
>> +    items:
>> +      - const: renesas,rzg3s-vbattb
>> +      - const: syscon
>> +      - const: simple-mfd
> 
> No, mfd does no look good. That's not a simple device anymore and you
> claim here child does not need vbat bclk, power domains and resets? That
> would be a big surprise, although technically possible.

I wasn't sure how this MFD will be received by the Renesas maintainers so I
kept it simple for this version.

In theory the VBAT clk, power domain and resets are specific to VBAT module
itself but, indeed, the child cannot work w/o these.

> 
> Please clarify: which of parent resources are needed for children?

VBAT clock, power domain are needed. Reset, too. In the current
implementation the reset is deasserted though parent by calling the
syscon_node_to_regmap(np->parent) in the clock driver.

> 
> ...
> 
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/clock/r9a08g045-cpg.h>
>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>> +
>> +    vbattb: vbattb@...5c000 {
>> +        compatible = "renesas,rzg3s-vbattb", "syscon", "simple-mfd";
>> +        reg = <0x1005c000 0x1000>;
>> +        ranges = <0 0 0x1005c000 0 0x1000>;
>> +        interrupts = <GIC_SPI 43 IRQ_TYPE_LEVEL_HIGH>;
>> +        interrupt-names = "tampdi";
>> +        clocks = <&cpg CPG_MOD R9A08G045_VBAT_BCLK>;
>> +        clock-names = "bclk";
>> +        power-domains = <&cpg>;
>> +        resets = <&cpg R9A08G045_VBAT_BRESETN>;
>> +        #address-cells = <2>;
>> +        #size-cells = <2>;
>> +        status = "disabled";
> 
> Drop

Could you please clarify this? Would you want me to drop the full node
(same for clock-controller node)?

Can you point me an example that you are thinking about?

Thank you,
Claudiu Beznea

> 
>> +
>> +        vbattclk: clock-controller@1c {
>> +            compatible = "renesas,rzg3s-vbattb-clk";
>> +            reg = <0 0x1c 0 0x10>;
>> +            clocks = <&cpg CPG_MOD R9A08G045_VBAT_BCLK>, <&vbattb_xtal>;
>> +            clock-names = "bclk", "vbattb_xtal";
>> +            #clock-cells = <0>;
>> +            power-domains = <&cpg>;
>> +            status = "disabled";
> 
> Drop
> 
>> +        };
>> +    };
>> +
>> +...
> 
> Best regards,
> Krzysztof
>