Re: [PATCH 0/4] video: ARM CLCD: add support of an optional GPIO to enable panel

Hi Vladimir,

On 07/01/17 23:32, Vladimir Zapolskiy wrote:

On 01/02/2017 04:22 PM, Russell King - ARM Linux wrote:

quoted

On Fri, Dec 30, 2016 at 09:23:59AM +0100, Linus Walleij wrote:

quoted

On Wed, Dec 21, 2016 at 4:27 AM, Vladimir Zapolskiy [off-list ref] wrote:

quoted

The changeset contains a number of cleanups, changed semantics of
init_panel() callback, which allows to simplify getting of panel
properties from panel device tree node, and a handling of optional
"enable-gpios" panel property, the latter is described in
display/panel/panel-dpi.txt device tree binding documentation, but
it has been unsupported by the ARM CLCD driver.

Vladimir Zapolskiy (4):
  video: ARM CLCD: sort included headers out alphabetically
  video: ARM CLCD: use panel device node for panel initialization
  video: ARM CLCD: use panel device node for getting backlight and mode
  video: ARM CLCD: add support of an optional GPIO to enable panel

As you may have seen Tomi has stepped down as FBDEV maintainer and
this subsystem is now orphaned.

I guess Andrew Morton merges patches for it in this case, he usually does.

But what we should actually do is create a new DRM driver for CLCD
in drivers/gpu/drm/arm/clcd*

It's maybe not a small undertaking :(

But in case you're interested in the job, I will pitch in and test the result
on all ARM reference designs plus Nomadik.

A DRM driver for it would probably be a good idea, but dealing with all
the weird and wonderful connection arrangements may not be that easy...

Linus, Russell,

I've immediately encountered a problem while porting the driver to DRM,
because LPC18xx/LPC43xx SoCs are powered by Cortex-M3/M4 cores and DRM
framework has build and runtime dependencies on MMU.

+Benjamin

In another thread Benjamin pointed at patch [1] in drm/kms part for noMMU.

[1] https://cgit.freedesktop.org/drm/drm-misc/commit/?idba0d98a188cc4ebd8ea54b37d274ec20465e464

Cheers
Vladimir

That said, in short term I would expect a continuation of support for
the legacy CLCD framebuffer driver, which works fine on MMU-less SoCs.

--
With best wishes,
Vladimir

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