linux-kernel - Re: [PATCH 0/3] auxdisplay: 7 segment LED display

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Date: Mon, 26 Feb 2024 17:04:58 +0100
From: Alexander Dahl <ada@...rsis.com>
To: Chris Packham <chris.packham@...iedtelesis.co.nz>
Cc: ojeda@...nel.org, robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
	conor+dt@...nel.org, andrew@...n.ch, gregory.clement@...tlin.com,
	sebastian.hesselbarth@...il.com, andy.shevchenko@...il.com,
	geert@...ux-m68k.org, pavel@....cz, lee@...nel.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-leds@...r.kernel.org
Subject: Re: [PATCH 0/3] auxdisplay: 7 segment LED display

Hello Chris,

Am Mon, Feb 26, 2024 at 10:34:20AM +1300 schrieb Chris Packham:
> This series adds a driver for a 7 segment LED display.
> 
> I'd like to get some feedback on how this could be extended to support >1
> character. The driver as presented is sufficient for my hardware which only has
> a single character display but I can see that for this to be generically useful
> supporting more characters would be desireable.
> 
> Earlier I posted an idea that the characters could be represended by
> sub-nodes[1] but there doesn't seem to be a way of having that and keeping the
> convenience of using devm_gpiod_get_array() (unless I've missed something).
> 
> [1] - https://lore.kernel.org/lkml/2a8d19ee-b18b-4b7c-869f-7d601cea30b6@alliedtelesis.co.nz/

Read that thread out of curiosity and I'm sorry if I'm late to the
party, but I wondered why this is limited to LEDs connected to GPIOs?

Would it be possible to somehow stack this on top of some existing
LEDs?  I mean you could wire a 7 segment device to almost any LED
driver IC with enough channels, couldn't you?

Greets
Alex

> 
> Chris Packham (3):
>   auxdisplay: Add 7 segment LED display driver
>   dt-bindings: auxdisplay: Add bindings for generic 7 segment LED
>   ARM: dts: marvell: Add 7 segment LED display on x530
> 
>  .../auxdisplay/generic,gpio-7seg.yaml         |  40 +++++
>  .../boot/dts/marvell/armada-385-atl-x530.dts  |  13 +-
>  drivers/auxdisplay/Kconfig                    |   7 +
>  drivers/auxdisplay/Makefile                   |   1 +
>  drivers/auxdisplay/seg-led.c                  | 152 ++++++++++++++++++
>  5 files changed, 212 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/devicetree/bindings/auxdisplay/generic,gpio-7seg.yaml
>  create mode 100644 drivers/auxdisplay/seg-led.c
> 
> -- 
> 2.43.2
> 
>