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From: Tingguo Cheng <tingguo.cheng@oss.qualcomm.com>
To: Bjorn Andersson <andersson@kernel.org>
Cc: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>,
	Konrad Dybcio <konradybcio@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	kernel@oss.qualcomm.com, linux-arm-msm@vger.kernel.org,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Kamal Wadhwa <kamal.wadhwa@oss.qualcomm.com>,
	Rakesh Kota <rakesh.kota@oss.qualcomm.com>,
	Fenglin Wu <fenglin.wu@oss.qualcomm.com>
Subject: Re: [PATCH] arm64: dts: qcom: hamoa-iot-evk: enable pwm rgb leds
Date: Tue, 28 Oct 2025 12:48:57 +0800	[thread overview]
Message-ID: <305b9b6b-2003-48ab-97d0-c60226e1493b@oss.qualcomm.com> (raw)
In-Reply-To: <nepbosujmpldx5exylkqjylonntj6v3p4jnnoyxstmbmilb7jc@t65dwpxzorg7>


On 10/26/2025 11:15 AM, Bjorn Andersson wrote:
> On Tue, Oct 21, 2025 at 02:29:22PM +0800, Tingguo Cheng wrote:
>> On 10/17/2025 4:09 PM, Konrad Dybcio wrote:
>>> On 10/17/25 10:06 AM, Tingguo Cheng wrote:
>>>> Add red, green and blue LED channels for the RGB device connected to
>>>> PMC8380C PWM-LED pins.
>>>>
>>>> Signed-off-by: Tingguo Cheng<tingguo.cheng@oss.qualcomm.com>
>>>> ---
>>> Just to make sure, is this a "multicolor LED" consisting of 3 ones,
>>> and *not* three LEDs that are supposed to communicate different
>>> functions (i.e. network, power, disk i/o)?
>> Yes, it's a multicolor LED composed of three individual LEDs within a single
>> package—not three separate LEDs for different functions like network, power,
>> or disk I/O.
>> However, there's one exception worth mentioning:
>> The blue channel is connected to two sourcing signals—the EDL indicator and
>> the PMIC PWM-RGB blue LED—via two resistors. These resistors allow selection
>> between the two sources.
>> By default, the board is configured with the resistor soldered to connect
>> the blue LED to the EDL indicator.
>> To support software control, I’ve added the blue channel in the DTS,
>> enabling the capability to light the blue LED from the software side.
>> Some developers may choose to re-solder the resistor to connect the blue LED
>> to the PMIC PWM-RGB output instead, depending on their hardware setup.
> Sounds like we have a RG LED, and if the user chooses to modify their
> hardware, they have different hardware...which they can easily describe
> by updating their DeviceTree.
>
>
> It's a bit weird, but does it work to make this LED_COLOR_ID_MULTI with
> just the RED and GREEN channels described?

Yes, I tired before with enabling RED and GREEN only, it works. (What 
you said makes sense)

Let me send V2 for *only enabling RED and GREEN*

>
> Regards,
> Bjorn
>
>>> Konrad

      reply	other threads:[~2025-10-28  4:49 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-17  8:06 Tingguo Cheng
2025-10-17  8:09 ` Konrad Dybcio
2025-10-21  6:29   ` Tingguo Cheng
2025-10-21  9:47     ` Konrad Dybcio
2025-10-26  3:15     ` Bjorn Andersson
2025-10-28  4:48       ` Tingguo Cheng [this message]

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