From: Daniel Thompson <daniel@riscstar.com>
To: "A. Sverdlin" <alexander.sverdlin@siemens.com>
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
Andrew Davis <afd@ti.com>, Lee Jones <lee@kernel.org>,
Pavel Machek <pavel@kernel.org>,
Daniel Thompson <danielt@kernel.org>,
Jingoo Han <jingoohan1@gmail.com>, Helge Deller <deller@gmx.de>,
linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org
Subject: Re: [PATCH 2/2] leds: lp8864: Register a backlight device
Date: Mon, 24 Aug 2026 10:33:16 +0100 [thread overview]
Message-ID: <aowP3K7sgXKnsonS@aspen.lan> (raw)
In-Reply-To: <20260817170817.1933046-3-alexander.sverdlin@siemens.com>
On Mon, Aug 17, 2026 at 07:08:15PM +0200, A. Sverdlin wrote:
> From: Alexander Sverdlin <alexander.sverdlin@siemens.com>
>
> The LP8864/LP8866 is a display-cluster LED backlight driver. Expose a
> standard backlight class interface in addition to the LED class device,
> so it can be used by display/panel stacks that expect a backlight.
>
> Use the new devm_led_backlight_register() helper, which spawns a
> led-backlight device driven by our LED and tied to the I2C device
> lifetime. This keeps the driver a plain LED driver, requires no
> device-tree changes and remains backwards compatible with existing DTs.
> It is a no-op when the led-backlight support is not enabled.
... but when led-backlight support is enabled it will prohibit the use
of the LED sysfs interface.
Having zero DT changes is a nice property but it seems rather fragile to
change the ABI the userspace must use to manipulate the LED based on
CONFIG_LED_BL.
Is there no way to explictly configure which ABI should be used?
Daniel.
next prev parent reply other threads:[~2026-08-24 9:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-17 17:08 [PATCH 0/2] leds: lp8864: Expose a backlight via led_bl helper A. Sverdlin
2026-08-17 17:08 ` [PATCH 1/2] backlight: led_bl: Add devm_led_backlight_register() helper A. Sverdlin
2026-08-17 17:18 ` sashiko-bot
2026-08-18 7:03 ` Sverdlin, Alexander
2026-08-24 9:17 ` Daniel Thompson
2026-08-17 17:08 ` [PATCH 2/2] leds: lp8864: Register a backlight device A. Sverdlin
2026-08-17 17:15 ` sashiko-bot
2026-08-24 9:33 ` Daniel Thompson [this message]
2026-08-24 15:39 ` Andrew Davis
2026-08-25 9:15 ` Daniel Thompson
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