Thread (41 messages) flat view 41 messages, 6 authors, 1d ago

Re: [PATCH 15/16] backlight: remove pandora_bl

From: Andreas Kemnade <andreas@kemnade.info>
Date: 2026-08-10 20:34:50
Also in: dri-devel, linux-arm-kernel, linux-devicetree, linux-omap, linux-sound, lkml

On Mon, 10 Aug 2026 20:30:13 +0200
"H. Nikolaus Schaller" [off-list ref] wrote:
quoted
Yes that is what I mean. It needs to be ported somewhere. If it can be ported to
some compatible = "pwm_bl_for_tps61161" or what fits best it will be fine. Or it
could be in some compatible = "pandora_bl" driver.

Has to be worked out when the development machines are not blocked by 3 or 4 other
projects already running in parallel :)  
Nevertheless I did a quick look into the pandora_bl driver structure.

Here are my findings:
- the code fragment is part of pandora_backlight_update_status()
- priv->old_state remembers if brighness was set to 0 or not
- so this code triggers on any change from bright = 0 to bright > 0
- the pandora_bl driver is the only one to use TWL_MODULE_PWM besides twl-pwm

So the most natural way of transplanting this appears to me:
- add this logic to the twl-pwm driver
That chip could be connected to any pwm driver, so
it does not make sense to have that in a pwm driver.

So it belongs into a backlight driver. And since it shared so much
code with the pwm_bl, it could be extended.
The compatible should have pwm in the name to be able to also add
a w1 driver later.

Regards,
Andreas
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