Re: [RFC PATCH 1/7] dt-bindings: rtc: sun6i: Add H616 and R329 compatibles

[Samuel Holland <samuel@sholland.org>]

On 9/2/21 10:27 AM, Rob Herring wrote:
> On Wed, Sep 01, 2021 at 12:39:45AM -0500, Samuel Holland wrote:
>> For these new SoCs, start requiring a complete list of input clocks.
>>
>> For H616, this means bus, hosc, and pll-32k. For R329, this means ahb,
>> bus, and hosc; and optionally ext-osc32k.
>>
>> I'm not sure how to best represent this in the binding...
>>
>> Signed-off-by: Samuel Holland <samuel@sholland.org>
>> ---
>>  .../bindings/rtc/allwinner,sun6i-a31-rtc.yaml | 55 +++++++++++++++++--
>>  include/dt-bindings/clock/sun50i-rtc.h        | 12 ++++
>>  2 files changed, 61 insertions(+), 6 deletions(-)
>>  create mode 100644 include/dt-bindings/clock/sun50i-rtc.h
>>
>> diff --git a/Documentation/devicetree/bindings/rtc/allwinner,sun6i-a31-rtc.yaml b/Documentation/devicetree/bindings/rtc/allwinner,sun6i-a31-rtc.yaml
>> index beeb90e55727..3e085db1294f 100644
>> --- a/Documentation/devicetree/bindings/rtc/allwinner,sun6i-a31-rtc.yaml
>> +++ b/Documentation/devicetree/bindings/rtc/allwinner,sun6i-a31-rtc.yaml
>> @@ -26,6 +26,8 @@ properties:
>>            - const: allwinner,sun50i-a64-rtc
>>            - const: allwinner,sun8i-h3-rtc
>>        - const: allwinner,sun50i-h6-rtc
>> +      - const: allwinner,sun50i-h616-rtc
>> +      - const: allwinner,sun50i-r329-rtc
> 
> Can you please make all the single entry cases a single 'enum'.
> 
>>  
>>    reg:
>>      maxItems: 1
>> @@ -37,7 +39,24 @@ properties:
>>        - description: RTC Alarm 1
>>  
>>    clocks:
>> -    maxItems: 1
>> +    minItems: 1
>> +    maxItems: 4
>> +
>> +  clock-names:
>> +    minItems: 1
>> +    maxItems: 4
>> +    items:
>> +      - anyOf:
> 
> This says the first entry is any of these. What about the rest of them?

Oh, right. The list below is the list of all possible clocks.

>> +          - const: ahb
>> +            description: AHB parent for SPI bus clock
> 
> The description should go in 'clocks'.

Will do for v2.

> The order should be defined as well with the first clock being the
> one that existed previously.

The only way I know how to further refine the list is with
minItems/maxItems. My problem is that 1) some clocks are only valid for
certain SoCs, and 2) some clocks are optional, depending on how the
board is wired. So there is no single order where the "valid"
combinations are prefixes of the "possible" combinations of clocks.

Or in other words, how can I say "clocks #1 and #2 from this list are
required, and #4 is optional, but #3 is not allowed"?

Some concrete examples, with the always-required clocks moved to the
beginning:

H6:
 - bus: required
 - hosc: required
 - ahb: not allowed
 - ext-osc32k: optional
 - pll-32k: not allowed

H616:
 - bus: required
 - hosc: required
 - ahb: not allowed
 - ext-osc32k: not allowed
 - pll-32k: required

R329:
 - bus: required
 - hosc: required
 - ahb: required
 - ext-osc32k: optional
 - pll-32k: not allowed

Should I just move the entire clocks/clock-items properties to if/then
blocks based on the compatible?

>> +          - const: bus
>> +            description: AHB/APB bus clock for register access
>> +          - const: ext-osc32k
>> +            description: External 32768 Hz oscillator input
>> +          - const: hosc
>> +            description: 24 MHz oscillator input
>> +          - const: pll-32k
>> +            description: 32 kHz clock divided from a PLL
>>  
>>    clock-output-names:
>>      minItems: 1
>> @@ -85,6 +104,9 @@ allOf:
>>              enum:
>>                - allwinner,sun8i-h3-rtc
>>                - allwinner,sun50i-h5-rtc
>> +              - allwinner,sun50i-h6-rtc
>> +              - allwinner,sun50i-h616-rtc
>> +              - allwinner,sun50i-r329-rtc
>>  
>>      then:
>>        properties:
>> @@ -96,13 +118,35 @@ allOf:
>>        properties:
>>          compatible:
>>            contains:
>> -            const: allwinner,sun50i-h6-rtc
>> +            enum:
>> +              - allwinner,sun50i-h616-rtc
>> +              - allwinner,sun50i-r329-rtc
>>  
>>      then:
>> +      clocks:
>> +        minItems: 3 # bus, hosc, and (pll-32k [H616] or ahb [R329])
>> +
>> +      clock-names:
>> +        minItems: 3
>> +
>> +      required:
>> +        - clock-names
>> +
>> +    else:
>> +      required:
>> +        - clock-output-names
>> +
>> +  - if:
>> +      properties: clock-names
>> +
>> +    then:
>> +      required:
>> +        - clocks # hosc is required
>> +
>> +    else:
>>        properties:
>> -        clock-output-names:
>> -          minItems: 3
>> -          maxItems: 3
>> +        clocks:
>> +          maxItems: 1 # only ext-osc32k is allowed
>>  
>>    - if:
>>        properties:
>> @@ -127,7 +171,6 @@ required:
>>    - compatible
>>    - reg
>>    - interrupts
>> -  - clock-output-names
>>  
>>  additionalProperties: false
>>  
>> diff --git a/include/dt-bindings/clock/sun50i-rtc.h b/include/dt-bindings/clock/sun50i-rtc.h
>> new file mode 100644
>> index 000000000000..d45e3ff4e105
>> --- /dev/null
>> +++ b/include/dt-bindings/clock/sun50i-rtc.h
>> @@ -0,0 +1,12 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
> 
> Dual license please.

Will do for v2.

Regards,
Samuel

>> +
>> +#ifndef _DT_BINDINGS_CLK_SUN50I_RTC_CCU_H_
>> +#define _DT_BINDINGS_CLK_SUN50I_RTC_CCU_H_
>> +
>> +#define CLK_OSC32K		0
>> +#define CLK_OSC32K_FANOUT	1
>> +#define CLK_IOSC		2
>> +
>> +#define CLK_RTC_SPI		8
>> +
>> +#endif /* _DT_BINDINGS_CLK_SUN50I_RTC_CCU_H_ */
>> -- 
>> 2.31.1
>>
>>