linux-kernel - Re: Droid 4 backlight support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <9285721b-8060-df59-7cdb-9cdd00b843ca@gmail.com>
Date:   Fri, 24 May 2019 23:49:10 +0200
From:   Jacek Anaszewski <jacek.anaszewski@...il.com>
To:     Pavel Machek <pavel@....cz>, linux-leds@...r.kernel.org,
        linux-kernel@...r.kernel.org, dmurphy@...com,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-omap@...r.kernel.org, tony@...mide.com, sre@...nel.org,
        nekit1000@...il.com, mpartap@....net, merlijn@...zup.org
Subject: Re: Droid 4 backlight support

Hi,

On 5/24/19 12:00 AM, Pavel Machek wrote:
> Hi!
> 
> Good news .. we have driver for backlight in mainline, AFAICT.
> 
> Bad news .. it is called "lm3532::backlight" or something like that. I
> guess we should switch to ":backlight" or something? It is quite
> important to do that before someone starts to use the ABI...
> 
> And now... we have the driver, but it is not connected to the
> backlight subsystem. I guess we could make the LED "default on" for
> now... but if there's better plan, let me know.

backlight trigger is added to fb_notifier_list
defined in drivers/video/fbdev/core/fb_notify.c.
Backlight subsystem is registered on the same notifications
in drivers/video/backlight.backlight.c.

So they are somehow related.

Regarding the LED class device name - when I tried to come up
with a description for each standardized LED function I realized
that in case of many functions it would be indeed very useful
to have devicename. For backlight LED it would be "associated
frame buffer device node name, e.g. fb0".

Attached is what I came up with, and I was going to send to the
list officially with the v5 of LED naming patch set.

-- 
Best regards,
Jacek Anaszewski

View attachment "led-functions.txt" of type "text/plain" (6441 bytes)