Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210625125902.1162428-1-geert@linux-m68k.org>
 <20210625125902.1162428-19-geert@linux-m68k.org> <20210625223916.7e00e710@thinkpad>
 <20210625224001.115c938a@thinkpad>
In-Reply-To: <20210625224001.115c938a@thinkpad>
From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Mon, 28 Jun 2021 11:21:08 +0200
Message-ID: <CAMuHMdXYLkoS7hTi1OZx7PMSCcfAR9YviJMN-x_dWpbz5KW+JA@mail.gmail.com>
Subject: Re: [PATCH v2 18/18] auxdisplay: ht16k33: Add segment display LED support
To:     Marek Behun <marek.behun@nic.cz>
Cc:     Robin van der Gracht <robin@protonic.nl>,
        Rob Herring <robh+dt@kernel.org>,
        Miguel Ojeda <ojeda@kernel.org>,
        Paul Burton <paulburton@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Pavel Machek <pavel@ucw.cz>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        linux-leds <linux-leds@vger.kernel.org>,
        "open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Hi Marek,

On Fri, Jun 25, 2021 at 10:40 PM Marek Behun <marek.behun@nic.cz> wrote:
> On Fri, 25 Jun 2021 22:39:16 +0200
> Marek Behun <marek.behun@nic.cz> wrote:
> > On Fri, 25 Jun 2021 14:59:02 +0200
> > Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > Instantiate a single LED for a segment display.  This allows the user to
> > > control display brightness and blinking through the LED class API and
> > > triggers, and exposes the display color.
> > > The LED will be named "auxdisplay:<color>:backlight".
> >
> > What if there are multiple "auxdisplay"s ?
> > Doesn't this subsystem have IDs? So that you can use auxdisplayN for
> > device name, for example?
>
> Or if this driver creates a fbdev, maybe "fb<N>" for devicename?

This LED device is only registered when using the HT16K33 to drive
segment displays.
When driving a dot matrix display, the driver still use fbdev and
devm_backlight_device_register(), for backwards compatibility.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds