Re: [PATCH v3 01/12] dt-bindings: clock: renesas,r9a08g045-vbattb: Document VBATTB

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

On 31.08.2024 01:06, Alexandre Belloni wrote:
> On 30/08/2024 12:46:33-0500, Rob Herring wrote:
>> On Fri, Aug 30, 2024 at 04:02:07PM +0300, Claudiu wrote:
>>> From: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>>
>>> The VBATTB IP of the Renesas RZ/G3S SoC controls the clock for RTC,
>>> the tamper detector and a small general usage memory of 128B. Add
>>> documentation for it.
>>>
>>> Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>> ---
>>>
>>> Changes in v3:
>>> - moved the file to clock dt bindings directory as it is the
>>>   only functionality supported at the moment; the other functionalities
>>>   (tamper detector, SRAM) are offered though register spreaded
>>>   though the address space of the VBATTB IP and not actually
>>>   individual devices; the other functionalities are not
>>>   planned to be supported soon and if they will be I think they
>>>   fit better on auxiliary bus than MFD
>>> - dropped interrupt names as requested in the review process
>>> - dropped the inner node for clock controller
>>> - added #clock-cells
>>> - added rtx clock
>>> - updated description for renesas,vbattb-load-nanofarads
>>> - included dt-bindings/interrupt-controller/irq.h in examples section
>>>
>>> Changes in v2:
>>> - changed file name and compatible
>>> - updated title, description sections
>>> - added clock controller part documentation and drop dedicated file
>>>   for it included in v1
>>> - used items to describe interrupts, interrupt-names, clocks, clock-names,
>>>   resets
>>> - dropped node labels and status
>>> - updated clock-names for clock controller to cope with the new
>>>   logic on detecting the necessity to setup bypass
>>>
>>>  .../clock/renesas,r9a08g045-vbattb.yaml       | 81 +++++++++++++++++++
>>>  1 file changed, 81 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml b/Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml
>>> new file mode 100644
>>> index 000000000000..29df0e01fae5
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/clock/renesas,r9a08g045-vbattb.yaml
>>> @@ -0,0 +1,81 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/clock/renesas,r9a08g045-vbattb.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Renesas Battery Backup Function (VBATTB)
>>> +
>>> +description:
>>> +  Renesas VBATTB is an always on powered module (backed by battery) which
>>> +  controls the RTC clock (VBATTCLK), tamper detection logic and a small
>>> +  general usage memory (128B).
>>> +
>>> +maintainers:
>>> +  - Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: renesas,r9a08g045-vbattb
>>> +
>>> +  reg:
>>> +    maxItems: 1
>>> +
>>> +  interrupts:
>>> +    items:
>>> +      - description: tamper detector interrupt
>>> +
>>> +  clocks:
>>> +    items:
>>> +      - description: VBATTB module clock
>>> +      - description: RTC input clock (crystal oscillator or external clock device)
>>> +
>>> +  clock-names:
>>> +    items:
>>> +      - const: bclk
>>> +      - const: rtx
>>> +
>>> +  '#clock-cells':
>>> +    const: 1
>>> +
>>> +  power-domains:
>>> +    maxItems: 1
>>> +
>>> +  resets:
>>> +    items:
>>> +      - description: VBATTB module reset
>>> +
>>> +  renesas,vbattb-load-nanofarads:
>>
>> Use defined units, don't add your own. So -picofarads should work for 
>> you.
> 
> We have a generic quartz-load-femtofarads property for RTCs which is
> what you define because the driver has VBATTB_XOSCCR_XSEL_4_PF which I
> guess is 4 pF which is 0.004 nF and 4000 fF.

I'll use this one in the next version.

Thank you for your review,
Claudiu Beznea

> 
>>
>>> +    description: load capacitance of the on board crystal oscillator
>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>> +    enum: [ 4000, 7000, 9000, 12500 ]
>>> +
>>> +required:
>>> +  - compatible
>>> +  - reg
>>> +  - interrupts
>>> +  - clocks
>>> +  - clock-names
>>> +  - '#clock-cells'
>>> +  - power-domains
>>> +  - resets
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    #include <dt-bindings/clock/r9a08g045-cpg.h>
>>> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
>>> +    #include <dt-bindings/interrupt-controller/irq.h>
>>> +
>>> +    vbattb@1005c000 {
>>
>> clock-controller@...
>>
>>> +        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";
>>> +        #clock-cells = <1>;
>>> +        power-domains = <&cpg>;
>>> +        resets = <&cpg R9A08G045_VBAT_BRESETN>;
>>> +        renesas,vbattb-load-nanofarads = <12500>;
>>> +    };
>>> -- 
>>> 2.39.2
>>>
>