From: Jyri Sarha <jsarha@ti.com>
To: Tomi Valkeinen <tomi.valkeinen@ti.com>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>
Cc: Pantelis Antoniou <pantelis.antoniou@konsulko.com>,
David Airlie <airlied@linux.ie>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
dri-devel <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH 00/12] of: overlay: clean up device tree overlay code
Date: Tue, 17 Oct 2017 11:43:12 +0300 [thread overview]
Message-ID: <0de3ee8a-5dca-8f3b-67aa-6d7f405828f6@ti.com> (raw)
In-Reply-To: <96045775-4142-1d2d-52f6-d76c0a982461@ti.com>
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
On 10/05/17 11:33, Jyri Sarha wrote:
> On 10/05/17 09:53, Tomi Valkeinen wrote:
>> On 04/10/17 17:56, Rob Herring wrote:
>>> On Mon, Oct 2, 2017 at 10:53 PM, <frowand.list@gmail.com> wrote:
>>>> From: Frank Rowand <frank.rowand@sony.com>
>>>>
>>>> I have found the device tree overlay code to be difficult to read and
>>>> maintain. This patch series attempts to improve that situation.
>>>>
>>>> The cleanup includes some changes visible to users of overlays. The
>>>> only in kernel user of overlays is fixed up for those changes. The
>>>> in kernel user is:
>>>>
>>>> drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c
>>>
>>> At what point can we remove this? I'm assuming at some point users
>>> will need to update their dtb's for other reasons and this becomes
>>> obsolete.
>>
>> To be honest, I have no idea, or how to find that out.
>>
>
> I think the first approach could be setting the DRM_TILCDC_SLAVE_COMPAT
> default to n and listen if there is any reports about breakage.
>
After giving it more thought. Maybe we can drop the
DRM_TILCDC_SLAVE_COMPAT in v4.16. 2017 LTS is out already, so there
should be plenty of time for whoever is still using the legacy DTBs to
get rid of them.
>> Do we need to get rid of it? Afaik, we haven't do much (or any?)
>> maintenance on tilcdc_slave_compat.c since it was written, so from our
>> perspective it's been a minimal burden. Is it creating burden for others?
>>
>> Is the approach done with tilcdc_slave_compat.c something that's not
>> recommended? I'm sure similar situations happen with other drivers too,
>> and I think it's a good idea to have a recommended way of keeping
>> compatibility.
>>
>
> For tilcdc I would say that we soon need a similar mechanism to get rid
> off tilcdc internal panel driver and to start using generic panel
> drivers instead. That is, if we want to keep the kernel compatible with
> old devicetree blobs.
>
Actually for tilcdc this is not that bad. The messy tilcdc slave
mechanism has been gotten rid of. The rest of tilcdc specific legacy
drivers - the tilcdc legacy panel support and the tilcdc legacy tfp410
driver - do not have any external dependencies and they can basically
remain there for ever for backward compatibility.
But in general, a generic mechanism to translate legacy DTBs to follow a
new binding would be a handy tool in keeping the drivers clean while
keeping up the support for legacy DTBs.
Best regards,
Jyri
next prev parent reply other threads:[~2017-10-17 8:44 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-03 3:53 frowand.list
2017-10-03 3:53 ` [PATCH 01/12] of: overlay.c: Remove comments that state the obvious, to reduce clutter frowand.list
2017-10-03 3:53 ` [PATCH 02/12] of: overlay.c: Convert comparisons to zero or NULL to logical expressions frowand.list
2017-10-03 3:53 ` [PATCH 03/12] of: overlay: rename identifiers to more reflect what they do frowand.list
2017-10-03 3:53 ` [PATCH 04/12] of: overlay: rename identifiers in dup_and_fixup_symbol_prop() frowand.list
2017-10-03 3:53 ` [PATCH 05/12] of: overlay: minor restructuring frowand.list
2017-10-03 3:53 ` [PATCH 06/12] of: overlay: detect cases where device tree may become corrupt frowand.list
2017-10-03 3:53 ` [PATCH 07/12] of: overlay: expand check of whether overlay changeset can be removed frowand.list
2017-10-03 3:53 ` [PATCH 08/12] of: overlay: loosen overly strict phandle clash check frowand.list
2017-10-03 3:53 ` [PATCH 09/12] of: overlay: avoid race condition between applying multiple overlays frowand.list
2017-10-04 15:19 ` Rob Herring
2017-10-05 3:29 ` Frank Rowand
2017-10-10 18:40 ` Rob Herring
2017-10-10 19:39 ` Frank Rowand
2017-10-10 21:06 ` Rob Herring
2017-10-11 0:53 ` Frank Rowand
2017-10-11 1:41 ` Frank Rowand
2017-10-03 3:53 ` [PATCH 10/12] of: overlay: simplify applying symbols from an overlay frowand.list
2017-10-03 3:53 ` [PATCH 11/12] of: overlay: remove a dependency on device node full_name frowand.list
2017-10-03 3:53 ` [PATCH 12/12] of: overlay: remove unneeded check for NULL kbasename() frowand.list
2017-10-04 14:56 ` [PATCH 00/12] of: overlay: clean up device tree overlay code Rob Herring
2017-10-05 6:53 ` Tomi Valkeinen
2017-10-05 8:33 ` Jyri Sarha
2017-10-17 8:43 ` Jyri Sarha [this message]
2017-10-05 14:46 ` Rob Herring
2017-10-13 22:03 ` Frank Rowand
2017-10-16 20:55 ` Rob Herring
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