Hi Heiko,
在 2015/8/24 21:03, Heiko Stuebner 写道:
Hi Yakir,
Am Montag, 24. August 2015, 20:48:01 schrieb Yakir Yang:
在 08/24/2015 12:20 PM, Krzysztof Kozlowski 写道:
On 24.08.2015 11:42, Yakir Yang wrote:
Hi Krzysztof,
在 08/23/2015 07:43 PM, Krzysztof Kozlowski 写道:
2015-08-24 8:23 GMT+09:00 Rob Herring <robherring2@xxxxxxxxx>:
On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang <ykk@xxxxxxxxxxxxxx> wrote:
Analogix dp driver is split from exynos dp driver, so we just
make an copy of exynos_dp.txt, and then simplify exynos_dp.txt
Beside update some exynos dtsi file with the latest change
according to the devicetree binding documents.
You can't just change the exynos bindings and break compatibility. Is
there some agreement with exynos folks to do this?
No, there is no agreement. This wasn't even sent to Exynos maintainers.
Sorry about this one, actually I have add Exynos maintainers in version
1 & version 2,
but lose some maintainers in version 3, I would fix it in bellow
versions.
Additionally the patchset did not look interesting to me because of
misleading subject - Documentation instead of "ARM: dts:".
Yakir, please:
1. Provide backward compatibility. Mark old properties as deprecated
but still support them.
Do you mean that I should keep the old properties declare in
exynos-dp.txt,
but just mark them as deprecated flag.
That is one of ways how to do this. However more important is that
driver should still support old bindings so such code:
- if (of_property_read_u32(dp_node, "samsung,color-space",
+ if (of_property_read_u32(dp_node, "analogix,color-space",
is probably wrong. Will the driver support old DTB in the same way as it
was supporting before the change?
Okay, I got your means. So document is not the focus, the most important
is that
driver should support the old dts prop. If so the new analogix dp driver
should keep
the "samsung,color-space", rather then just mark it with [DEPRECATED] flag.
But from your follow suggest, I think you agree to update driver code,
and just mark
old prop with deprecated flag. If so I think such code would not be wrong
- if (of_property_read_u32(dp_node, "samsung,color-space",
+ if (of_property_read_u32(dp_node, "analogix,color-space",
In a generic driver, the property should have either none, or the analogix
prefix. But DT-properties need to be backwards compatible, meaning an older
Exynos devicetree should run unmodified with a newer kernel.
So the common course of action is to mark the old one as deprecated but still
test for both, so something like:
if (of_property_read_u32(dp_node, "analogix,color-space",
&dp_video_config->color_space))
if (of_property_read_u32(dp_node, "samsung,color-space",
&dp_video_config->color_space)) {
dev_err(dev, "failed to get color-space\n");
return ERR_PTR(-EINVAL);
}
Wow, thanks a lot for your explain and code, it do help me to understand
this suggest rightly :-)
Thanks,
- Yakir
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