Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <c13b67ec-c030-302a-6315-fad18323923a@linaro.org>
Date:   Wed, 30 Nov 2022 12:59:51 +0100
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.5.0
Subject: Re: [PATCH 2/3] dt-bindings: leds: add dt schema for
 worldsemi,ws2812b-spi
Content-Language: en-US
To:     Chuanhong Guo <gch981213@gmail.com>
Cc:     linux-leds@vger.kernel.org, Pavel Machek <pavel@ucw.cz>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Stanislav Jakubek <stano.jakubek@gmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Shawn Guo <shawnguo@kernel.org>,
        Johan Hovold <johan+linaro@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Sven Schwermer <sven.schwermer@disruptive-technologies.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
References: <20221129140955.137361-1-gch981213@gmail.com>
 <20221129140955.137361-3-gch981213@gmail.com>
 <98b72494-3188-76d5-2e24-9dc127a8b31a@linaro.org>
 <CAJsYDVJknDWKMW1tH0M=85tJOPG-HngxhhMzvJpk5qn_Q9mzAg@mail.gmail.com>
 <7b3f97f9-34af-413c-aaad-9108b4f36c51@linaro.org>
 <CAJsYDVKXvJZaqCBx7RSsfVZkKTGdbp78GHA4mvmUdQwyEyGkBQ@mail.gmail.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <CAJsYDVKXvJZaqCBx7RSsfVZkKTGdbp78GHA4mvmUdQwyEyGkBQ@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 30/11/2022 10:25, Chuanhong Guo wrote:
> Hi!
> 
> On Wed, Nov 30, 2022 at 5:08 PM Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org> wrote:
>> And that's exactly what I said - the compatibles should not include bus
>> information. The bus information comes from... the bus!
> 
> Oh. I thought there will be a conflict if there is a SPI driver and
> , say, an I2C driver with the same compatible string.

We already have such. For example: adi,adxl312

> 
>> [...]
>>>>
>>>> Why unit address is optional?
>>>
>>> It isn't. I copy-pasted it from led-class-multicolor.yaml and
>>> didn't check the exact regex.
>>> I'll fix it in the next version.
>>
>> Make it required and matching your case.
> 
> Got it.
> 
>> [...]
>>>>> +      default-intensity:
>>>>> +        description: |
>>>>> +          An array of 3 integer specifying the default intensity of each color
>>>>> +          components in this LED. <255 255 255> if unspecified.
>>>>> +        $ref: /schemas/types.yaml#/definitions/uint32-array
>>>>> +        minItems: 3
>> [...]
>> So this is brightness of each color...
> 
> I don't think so.
> See the kernel doc for multicolor LED:
> https://docs.kernel.org/leds/leds-class-multicolor.html
> This property sets the sysfs file multi_intensity while the
> actual LED brightness is controlled with another sysfs
> file called 'brightness'.
> Setting multi_intensity alone doesn't change the LED
> brightness at all.

If you had brightness, that would be correct. But you do not have
brightness, right? Therefore the final brightness is always:

subled[i].brightness = 255 * subled[i].intensity / max_brightness (also
255);

Or your bindings are incomplete...

Best regards,
Krzysztof