linux-kernel - Re: [PATCH v2 2/2] dt-bindings: add bindings for QCOM flash LED

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Date:   Mon, 10 Oct 2022 17:47:20 +0800
From:   Fenglin Wu <quic_fenglinw@...cinc.com>
To:     Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
CC:     <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Andy Gross" <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Pavel Machek <pavel@....cz>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        <linux-leds@...r.kernel.org>, <devicetree@...r.kernel.org>,
        "Subbaraman Narayanamurthy" <quic_subbaram@...cinc.com>,
        <quic_collinsd@...cinc.com>
Subject: Re: [PATCH v2 2/2] dt-bindings: add bindings for QCOM flash LED



On 2022/10/1 3:33, Rob Herring wrote:
> On Thu, Sep 29, 2022 at 02:40:05PM +0200, Krzysztof Kozlowski wrote:
>> On 29/09/2022 14:15, Fenglin Wu wrote:
>>> Add binding document for flash LED module inside Qualcomm Technologies,
>>> Inc. PMICs.
>>>
>>> Signed-off-by: Fenglin Wu <quic_fenglinw@...cinc.com>
>>
>> Thank you for your patch. There is something to discuss/improve.
>>
>>> +  reg:
>>> +    description: address offset of the flash LED controller
>>> +    maxItems: 1
>>> +
>>> +patternProperties:
>>> +  "^led[0-3]$":
>>
>> In such case: ^led-[0-9]$"
>>
>>> +    type: object
>>> +    $ref: common.yaml#
>>> +    unevaluatedProperties: false
>>> +    description: |
>>> +      Represents the physical LED components which are connected to the
>>> +      flash LED channels' output.
>>> +
>>> +    properties:
>>> +      led-sources:
> 
> This is for when the power source and LED connection are programmable.
> IOW, when 'reg' is not enough to describe the configuration. If you only
> have LED channels 1-4 with a fixed connection to LED pins/output 1-4,
> then use 'reg'.
> 
I think using led-sources here is more appropriate. The LED connection 
can be programmable to match with the board design. The flash module has 
4 channels (current outputs, indexed from 1 to 4) and the LEDs can be 
connected to either one or two of them depends on the design. Such as, 
if the design only requires LEDs with 1.5 A maximum current, then the HW 
just connects one channel to each LED and specify the corresponding 
channel index in the led-sources. Or if the design requires LEDs 
supporting up to 2 A maximum current, then the HW needs to gang 2 
channels' output together and specify the HW indices in led-sources 
accordingly.

>>> +        description: |
>>> +          The HW indices of the flash LED channels that connect to the
>>> +          physical LED
>>> +        allOf:
>>> +          - minItems: 1
>>> +            maxItems: 2
>>> +            items:
>>> +              enum: [1, 2, 3, 4]
>>> +
>>> +      led-max-microamp:
>>> +        description: |
>>> +          The maximum current value when LED is not operating in flash mode (i.e. torch mode)
>>> +          Valid values when an LED is connected to one flash LED channel:
>>> +            5000 - 500000, step by 5000
>>> +          Valid values when an LED is connected to two flash LED channels:
>>> +            10000 - 1000000, step by 10000
>>> +        minimum: 5000
>>> +        maximum: 1000000
> 
> anyOf:
>    - minimum: 5000
>      maximum: 500000
>      multipleOf: 5000
>    - minimum: 10000
>      maximum: 1000000
>      multipleOf: 10000
> 
> Drop any description that's captured by the constraints.
Thanks for the suggestion. I will update it accordingly.
> 
>>> +
>>> +      flash-max-microamp:
>>> +        description: |
>>> +          The maximum current value when LED is operating in flash mode.
>>> +          Valid values when an LED is connected to one flash LED channel:
>>> +            12500 - 1500000, step by 12500
>>> +          Valid values when an LED is connected to two flash LED channels:
>>> +            25000 - 2000000, step by 12500
>>> +        minimum: 12500
>>> +        maximum: 2000000
>>> +
>>> +      flash-max-timeout-us:
>>> +        description: |
>>> +          The maximum timeout value when LED is operating in flash mode.
>>> +          Valid values: 10000 - 1280000, step by 10000
>>> +        minimum: 10000
>>> +        maximum: 1280000
> 
> Similar comment for these 2.
Done
> 
>>> +
>>> +    required:
>>> +      - led-sources
>>> +      - led-max-microamp
>>> +
>>> +required:
>>> +  - compatible
>>> +  - reg
>>> +
>>> +additionalProperties: false
>>> +
>>> +examples:
>>> +  - |
>>> +    #include <dt-bindings/leds/common.h>
>>> +    spmi_bus {
>>
>> No underscores in node names, so just "bus"
> 
> SPMI is something else though...
Sure, will update it to spmi
>