[PATCH v3 06/14] Documentation: drm/bridge: add document for analogix_dp
ykk at rock-chips.com
Mon Aug 24 05:48:01 PDT 2015
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 at gmail.com>:
>>>> On Wed, Aug 19, 2015 at 9:50 AM, Yakir Yang <ykk at rock-chips.com> 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
driver should support the old dts prop. If so the new analogix dp driver
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",
And actually @Rob have suggest me to remove the prefix, just use
>> Let me show same examples, make
>> me understand your suggest rightly.
> exynos-dp already contains deprecated properties. Other ways of doing
> this would be:
> It depends up to you. The "touchscreen" looks good because it organizes
> old properties in a common section. In case of exynos-dp.txt you can add
> at beginning of file information about new bindings and mark everything
Whoops, thanks for your remind, I prefer the "touchscreen" style.
>> 1. "samsung,ycbcr-coeff" is abandoned in latest analogix-dp driver,
>> I should not carry this to analogix-dp.txt document. But I should
>> keep this in
>> exynos-dp.txt document, and mark them with an little "deprecated" flag.
>> Required properties for dp-controller:
>> -samsung,ycbcr-coeff (DEPRECATED):
>> YCbCr co-efficients for input video.
>> COLOR_YCBCR601 = 0, COLOR_YCBCR709 = 1
>> Is it right ?
> Yes, this is right.
>>> 2. Separate all DTS changes to a separate patch, unless bisectability
>>> would be hurt. Anyway you should prepare it in a such way that
>>> separation would be possible without breaking bisectability.
>> So I should separate this patch into two parts, one is name "Document:",
>> the other is "ARM: dts: ".
>> Honestly, I don't understand what the "bisectability" means in this case.
> I was referring to bisectability in general. The patchset should be
> fully bisectable which means that it does not introduce any issues
> during "git bisect". This effectively means that at each intermediate
> step (after applying each patch, one by one) every existing stuff works
> the same as previously without any regression. Including booting with
> old DTB.
Oh, thanks for your careful explain, so I guess your first comment is
the "bisectability" that if I only apply the 01 - 05 patches, kernel
could not bootup
normally, cause driver need "analogix,color-space" but DTB only have
>>> 3. Use proper subject for the patch changing DTS. This is not
>>> documentation change!
>> Hmm... when I separate this patch into two parts, I though I can keep
>> "Documentation" proper subject in this patch, and the other is the "ARM:
>> proper subject. Am I right ?
> Yes, you're right.
>>> 4. Please use script get_maintainers to obtain list of valid
>>> maintainers and CC-them with at least cover letter and patches
>>> requiring their attention.
>> Yeah, thanks.
> Sure. Now I found older versions of the patchset but previously there
> were no changes to the bindings. Again the prefix in subject is
> important to easily filter out and find necessary emails.
> BTW, I like the patchset because I like in general works which merge
> code and reduce duplicate stuff.
Aha, thanks :-D
> Best regards,
More information about the linux-arm-kernel