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Sun, 18 Jan 2026 08:48:12 -0800 (PST) Message-ID: <95a49665-f379-48a7-a2b5-d288cdfdc0a8@gmail.com> Date: Sun, 18 Jan 2026 22:18:32 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 1/2] dt-bindings: backlight: gpio-backlight: allow multiple GPIOs To: Daniel Thompson Cc: lee@kernel.org, danielt@kernel.org, jingoohan1@gmail.com, deller@gmx.de, pavel@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260105085120.230862-1-tessolveupstream@gmail.com> <20260105085120.230862-2-tessolveupstream@gmail.com> Content-Language: en-US From: tessolveupstream@gmail.com In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 14-01-2026 21:23, Daniel Thompson wrote: > On Tue, Jan 13, 2026 at 10:15:53AM +0530, tessolveupstream@gmail.com wrote: >> >> >> On 05-01-2026 15:25, Daniel Thompson wrote: >>> On Mon, Jan 05, 2026 at 02:21:19PM +0530, Sudarshan Shetty wrote: >>>> Update the gpio-backlight binding to support configurations that require >>>> more than one GPIO for enabling/disabling the backlight. >>>> >>>> Signed-off-by: Sudarshan Shetty >>>> --- >>>> .../bindings/leds/backlight/gpio-backlight.yaml | 12 +++++++++++- >>>> 1 file changed, 11 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml >>>> index 584030b6b0b9..1483ce4a3480 100644 >>>> --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml >>>> +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml >>>> @@ -17,7 +17,8 @@ properties: >>>> >>>> gpios: >>>> description: The gpio that is used for enabling/disabling the backlight. >>>> - maxItems: 1 >>>> + minItems: 1 >>>> + maxItems: 2 >>> >>> Why 2? >>> >> >> In the current design, the LVDS panel has a single backlight that >> is controlled by two GPIOs. Initially, It described as two separate >> backlight devices using the same gpio-backlight driver, since the >> existing driver supports only one GPIO per instance. >> >> So the maintainer suggested to extend the gpio-backlight driver >> and bindings to support multiple GPIOs. >> https://lore.kernel.org/all/q63bdon55app4gb2il5e7skyc6z2amcnaiqbqlhen7arkxphtb@3jejbelji2ti/ > > Right. So, once we support multiple GPIOs then why limit it to 2? > Okay, got the point. I'm removing the maxItems constraint entirely to allow any number of GPIOs as below: diff --git a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml index 1483ce4a3480..82698519daff 100644 --- a/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml +++ b/Documentation/devicetree/bindings/leds/backlight/gpio-backlight.yaml @@ -16,9 +16,11 @@ properties: const: gpio-backlight gpios: - description: The gpio that is used for enabling/disabling the backlight. + description: | + The gpio that is used for enabling/disabling the backlight. + Multiple GPIOs can be specified for panels that require several + enable signals. minItems: 1 - maxItems: 2 default-on: description: enable the backlight at boot. Does this approach work for you? > > Daniel.