On Tue, Feb 01, 2022 at 01:14:22AM +0100, Javier Martinez Canillas wrote:

On 1/31/22 22:30, Sam Ravnborg wrote:

quoted

On Mon, Jan 31, 2022 at 09:29:16PM +0100, Javier Martinez Canillas wrote:

...

quoted

The driver uses the pwms property for the backlight.
It would have been much better to bite the bullet and require the
backlight to be specified using a backlight node in the DT.
This is the standard way to do it and then the driver could use the
existing backlight driver rather than embedding a backlight driver here.

I did consider that. Because that would allow me to use a struct drm_panel
and as you said make the core to manage the backlight. But then decied to
just keep the backward compatibility with the existing binding to make it
easier for users to migrate to the DRM driver.

I wonder if we could make the driver to support both ? That is, to query
if there's a backlight with drm_panel_of_backlight() and if not found then
registering it's own backlight like the driver is currently doing.

If we keep 100% backward compatibility, just drop the old driver.
After all module name is not so important as compatibility strings.

The problem with no backward compatibility means that removal of old driver
makes users unhappy since DT is kinda ABI and we do not break it.

-- 
With Best Regards,
Andy Shevchenko