From: Eric Anholt <eric@anholt.net>
To: Russell King - ARM Linux <linux@armlinux.org.uk>
Cc: dri-devel@lists.freedesktop.org, tom.cooksey@arm.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] drm/pl111: Initial drm/kms driver for pl111
In-Reply-To: <20170317230949.GK21222@n2100.armlinux.org.uk>
References: <20170317224742.17219-1-eric@anholt.net> <20170317224742.17219-3-eric@anholt.net> <20170317230949.GK21222@n2100.armlinux.org.uk>
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Date: Fri, 17 Mar 2017 17:45:34 -0700
Message-ID: <87pohfv2dt.fsf@eliezer.anholt.net>
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Russell King - ARM Linux <linux@armlinux.org.uk> writes:

> On Fri, Mar 17, 2017 at 03:47:42PM -0700, Eric Anholt wrote:
>> This is a modesetting driver for the pl111 CLCD display controller
>> found on various ARM platforms such as the Versatile Express. The
>> driver has only been tested on the bcm911360_entphn platform so far,
>> with PRIME-based buffer sharing between vc4 and clcd.
>>=20
>> It reuses the existing devicetree binding, while not using quite as
>> many of its properties as the fbdev driver does (those are left for
>> future work).
>
> As we're multiplatform on ARM, and this is using the PL11x AMBA IDs,
> we must ensure that it's compatible with everything that the fbdev
> driver is compatible with... however, I suspect that's not worth the
> effort (unless Linus W wants it?)
>
> If we make it PL111 specific, then we don't need to handle Integrator
> CP, or the Versatile PB/AB weirdness.  The only thing left is the
> power etc enable bits on Realview which uses the PL111.  See the
> code for Realview in drivers/video/fbdev/amba-clcd-versatile.c.

Restricting to PL111 for now sounds good to me.

Those Realview bits look like they're turning on a power domain --
shouldn't we represent those as a regulator or a power domain?  If we
did, then plugging that into a panel driver sounds straightforward.
(that's assuming that they're powering panel. not the controller -- I
can't quite tell from the code I've browsed so far)


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