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

Andreas Kemnade <[email protected]> Mon, 10 Aug 2026 22:34:13 +0200

Newsgroups	org.kernel.vger.linux-omap,dev.linux.lists.mfd,org.freedesktop.lists.dri-devel,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-fbdev,org.kernel.vger.linux-kernel,org.kernel.vger.linux-sound
Message-ID	<[email protected]>

On Mon, 10 Aug 2026 20:30:13 +0200
"H. Nikolaus Schaller" <[email protected]> wrote:

> > 
> > 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