linux-kernel - Re: Linux support for a 7 segment LED display

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Message-ID: <344e00f9-a175-41d5-97dc-f60e771fea8d@alliedtelesis.co.nz>
Date: Mon, 19 Feb 2024 20:08:27 +0000
From: Chris Packham <Chris.Packham@...iedtelesis.co.nz>
To: Pavel Machek <pavel@....cz>
CC: "lee@...nel.org" <lee@...nel.org>, "linux-leds@...r.kernel.org"
	<linux-leds@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: Re: Linux support for a 7 segment LED display


On 20/02/24 04:34, Pavel Machek wrote:
> Hi!
>
>> I'm looking for something that I figured must exists but maybe it's so
>> niche that no-one has bothered to upstream a driver for it.
>>
>> I have a requirement to support a 7-segment LED display[1] (one that can
>> display a single digit from 0-9). Hardware wise it's just a bunch of
>> individual GPIOs connected to each segment (plus an extra one for a
>> dot). I can't see anything obvious in drivers/leds but maybe I'm looking
>> in the wrong place. Or maybe it's the kind of thing on PC hardware that
>> is just driven by the BIOS without the operating system knowing about it.
> Look at drivers/auxdisplay. I believe we have segment displays there.

Thanks for the pointer. I found ht16k33.c (and 
drivers/input/misc/yealink.c) which have support for 7 segment displays. 
Still not quite what I'd need to glue it together with GPIOs but I can 
see the direction one might head.