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From:   Nick Crews <ncrews@chromium.org>
Date:   Mon, 25 Mar 2019 14:24:09 -0600
Message-ID: <CAHX4x84qSZxZ51FiYZ4ELEmUKJnUvMy7OGQVSQv2xh7x-nC57A@mail.gmail.com>
Subject: Re: [PATCH 3/3] platform/chrome: Add Wilco EC keyboard backlight LEDs support
To:     Pavel Machek <pavel@ucw.cz>
Cc:     Enric Balletbo i Serra <enric.balletbo@collabora.com>,
        Benson Leung <bleung@chromium.org>, linux-leds@vger.kernel.org,
        jacek.anaszewski@gmail.com,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Duncan Laurie <dlaurie@chromium.org>,
        Simon Glass <sjg@google.com>,
        Guenter Roeck <groeck@google.com>,
        Dmitry Torokhov <dtor@google.com>, Simon Que <sque@google.com>
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On Fri, Mar 22, 2019 at 9:49 AM Nick Crews <ncrews@chromium.org> wrote:
>
> On Fri, Mar 22, 2019 at 5:35 AM Pavel Machek <pavel@ucw.cz> wrote:
> >
> > Hi!
> >
> > > The EC is in charge of controlling the keyboard backlight on
> > > the Wilco platform. We expose a standard LED class device at
> > > /sys/class/leds/wilco::kbd_backlight. This driver is modeled
> > > after the standard Chrome OS keyboard backlight driver at
> > > drivers/platform/chrome/cros_kbd_led_backlight.c
> >
> > Please make it platform::kbd_backlight . Userland should not need to
> > know what wilco is...
>
> The corresponding device for normal chromeos devices is
> "chromeos::kbd_backlight". I wanted to differentiate this device from
> that one, so I thought that "wilco" a similar level of specific-ness as
> "chromeos". Using "platform" seems too general. The power manager
> daemon that controls the backlight just searches for LEDs ending with
> "*:kbd_backlight" so it should work for that, and I figured any user just
> browsing through sysfs would be able to guess what the LED does.
>
> This is maybe a question for those who will need to maintain the
> Chrome OS system after adding this? Could some more
> Chrome OS-specific people chime in on this? I also CC'ed Simon
> Que, the author of the original driver (Simon, we are talking about
> https://lkml.org/lkml/2019/3/21/999)

From talking to Simon, since the interface is the same, I'll just keep the name
as "chromeos::kbd_backlight". This makes sense to me too. I'll send out a
patch fixing this.

>
> >
> > What is wilco, anyway?
>
> Wilco is a new Chrome OS device which does not use the same embedded
> controller as the rest of the Chrome OS ecosystem. Thus, we need this new
> driver because the old one will not be compatible.
>
> >
> >                                                                         Pavel
> > --
> > (english) http://www.livejournal.com/~pavelmachek
> > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html