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

Vladimir Zapolskiy vz at mleia.com
Sat Jan 7 15:32:00 PST 2017

On 01/02/2017 04:22 PM, Russell King - ARM Linux wrote:
> On Fri, Dec 30, 2016 at 09:23:59AM +0100, Linus Walleij wrote:
>> On Wed, Dec 21, 2016 at 4:27 AM, Vladimir Zapolskiy <vz at mleia.com> wrote:
>>> 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.

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,

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