linux-kernel - Re: [PATCH v2 2/7] backlight: qcom-wled: Support ovp values for PMI8994

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Message-ID: <0fe51f7f-9b77-4bff-ab1c-21c44a863a7a@oss.qualcomm.com>
Date: Fri, 9 Jan 2026 12:09:11 +0100
From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
To: barnabas.czeman@...nlining.org, Daniel Thompson <danielt@...nel.org>
Cc: Lee Jones <lee@...nel.org>, Jingoo Han <jingoohan1@...il.com>,
        Pavel Machek <pavel@...nel.org>, Rob Herring <robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
 <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Kiran Gunda <quic_kgunda@...cinc.com>, Helge Deller <deller@....de>,
        Luca Weiss <luca@...aweiss.eu>, Konrad Dybcio <konradybcio@...nel.org>,
        Eugene Lepshy <fekz115@...il.com>,
        Gianluca Boiano <morf3089@...il.com>,
        Alejandro Tafalla <atafalla@...on.com>,
        dri-devel@...ts.freedesktop.org, linux-leds@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        Daniel Thompson <daniel.thompson@...aro.org>,
        linux-arm-msm@...r.kernel.org, linux-fbdev@...r.kernel.org
Subject: Re: [PATCH v2 2/7] backlight: qcom-wled: Support ovp values for
 PMI8994

On 1/9/26 7:36 AM, barnabas.czeman@...nlining.org wrote:
> On 2026-01-08 12:28, Daniel Thompson wrote:
>> On Thu, Jan 08, 2026 at 04:43:20AM +0100, Barnabás Czémán wrote:
>>> WLED4 found in PMI8994 supports different ovp values.
>>>
>>> Fixes: 6fc632d3e3e0 ("video: backlight: qcom-wled: Add PMI8994 compatible")
>>> Reviewed-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
>>> Signed-off-by: Barnabás Czémán <barnabas.czeman@...nlining.org>
>>> ---
>>>  drivers/video/backlight/qcom-wled.c | 41 +++++++++++++++++++++++++++++++++++--
>>>  1 file changed, 39 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
>>> index a63bb42c8f8b..5decbd39b789 100644
>>> --- a/drivers/video/backlight/qcom-wled.c
>>> +++ b/drivers/video/backlight/qcom-wled.c
>>> @@ -1244,6 +1244,15 @@ static const struct wled_var_cfg wled4_ovp_cfg = {
>>>      .size = ARRAY_SIZE(wled4_ovp_values),
>>>  };
>>>
>>> +static const u32 pmi8994_wled_ovp_values[] = {
>>> +    31000, 29500, 19400, 17800,
>>> +};
>>> +
>>> +static const struct wled_var_cfg pmi8994_wled_ovp_cfg = {
>>> +    .values = pmi8994_wled_ovp_values,
>>> +    .size = ARRAY_SIZE(pmi8994_wled_ovp_values),
>>> +};
>>> +
>>
>> Do these *have* to be named after one of the two PMICs that implement
>> this OVP range.
>>
>> Would something like wled4_alternative_ovp_values[] (and the same
>> throughout the patch) be more descriptive?
> I don't know. I don't like the PMIC naming either but at least it
> descriptive about wich PMIC is needing these values.
> I think PMIC naming would be fine if compatibles what representing the
> same configurations would be deprecated and used as a fallback compatbile
> style.
> I mean we could kept the first added compatible for a configuration.
> Maybe they should be named diferently i don't know if WLEDs have subversion.

Every PMIC peripheral is versioned.

WLED has separate versioning for the digital and analog parts:

PMIC		ANA	DIG
---------------------------
PMI8937		2.0	1.0 (also needs the quirk)
PMI8950		2.0	1.0
PMI8994		2.0	1.0
PMI8996		2.1	1.0
PMI8998		3.1	3.0
PM660L		4.1	4.0

I don't know for sure if "PMIC4 with WLED ANA/DIG 3.x" a good
discriminant though..

Konrad