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From: cnegris01@gmail.com (Christian N)
To: kernelnewbies@lists.kernelnewbies.org
Subject: pwm_bl add framebuffer from fbcon
Date: Tue, 20 Nov 2018 07:32:34 -0300	[thread overview]
Message-ID: <CAPNHxoHZqpzPQrAg4pMrhXe254ihyPK+-t=hyRzksifROwer+A@mail.gmail.com> (raw)

Hi All

First at all I introduce my usecase
-My board based on ARM (OMPA4) can get a custom splash screen on booting
using fbcon.
-By Device Tree I can configure screen backlight with desired level.

i'm trying to turn on backlight when splash screen is displayed and not
before to avoid "white flashes".

I read
Documentation/devicetree/bindings/pwm/pwm.txt
Documentation/devicetree/bindings/leds/pwm-backlight.txt
Documentation/fb/...
https://www.kernel.org/doc/html/v4.14/admin-guide/kernel-parameters.html

Also I noticed that pwm_bl has pwm_backlight_check_fb operation, but I
didnt find a clear way to relate frame buffer used by fbcon with pwm_bl
related functions or how to customize by DT or kernel config which frame
buffer should be used by pwm_bl to turn on when valid data is ready in fb

Any hints will be apreciated.

Regards
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From: Christian N <cnegris01@gmail.com>
To: kernelnewbies@kernelnewbies.org
Subject: pwm_bl add framebuffer from fbcon
Date: Tue, 20 Nov 2018 07:32:34 -0300	[thread overview]
Message-ID: <CAPNHxoHZqpzPQrAg4pMrhXe254ihyPK+-t=hyRzksifROwer+A@mail.gmail.com> (raw)
Message-ID: <20181120103234.pJZJL-kqaKpKg8kbUFsvJO7x3bXpBlAYdjWNYakyO_o@z> (raw)


[-- Attachment #1.1: Type: text/plain, Size: 841 bytes --]

Hi All

First at all I introduce my usecase
-My board based on ARM (OMPA4) can get a custom splash screen on booting
using fbcon.
-By Device Tree I can configure screen backlight with desired level.

i'm trying to turn on backlight when splash screen is displayed and not
before to avoid "white flashes".

I read
Documentation/devicetree/bindings/pwm/pwm.txt
Documentation/devicetree/bindings/leds/pwm-backlight.txt
Documentation/fb/...
https://www.kernel.org/doc/html/v4.14/admin-guide/kernel-parameters.html

Also I noticed that pwm_bl has pwm_backlight_check_fb operation, but I
didnt find a clear way to relate frame buffer used by fbcon with pwm_bl
related functions or how to customize by DT or kernel config which frame
buffer should be used by pwm_bl to turn on when valid data is ready in fb

Any hints will be apreciated.

Regards

[-- Attachment #1.2: Type: text/html, Size: 1245 bytes --]

[-- Attachment #2: Type: text/plain, Size: 170 bytes --]

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             reply	other threads:[~2018-11-20 10:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-20 10:32 Christian N [this message]
2018-11-20 10:32 ` pwm_bl add framebuffer from fbcon Christian N

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