Re: [PATCH] ARM: dts: Add Exynos5250 Snow Rev5+ support

[Kukjin Kim <kgene@kernel.org>]

On 09/30/15 09:30, Krzysztof Kozlowski wrote:
> On 29.09.2015 20:57, Javier Martinez Canillas wrote:
>> There are 2 revisions of the Exynos5250 Snow Chromebook that were shipped:
>> Rev4 and Rev5. The only difference between these 2 revisions is the codec,
>> Rev4 has a max98095 codec while Rev5 has a max98090.
>>
>> Mainline only supports Rev4 so this patch moves the common device nodes to
>> a DTSI file and adds a DTS for the Exynos5250 Snow Rev5.
>>
>> The Snow Rev5 DTS is based on the DTS found in the ChromiumOS 3.8 tree.
>>
>> Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
>>
>> ---
>>
>> The DTS in the vendor ChromeOS tree are called exynos5250-snow-rev{4,5}.dtb
>> but I decided to leave Rev4 as exynos5250-snow.dtb to avoid breaking u-boot
>> that has CONFIG_DEFAULT_DEVICE_TREE="exynos5250-snow" in snow_defconfig.
>>
>> Also, ChromiumOS Rev4 DTS has "google,snow-rev4" in its compatible string
>> but was not added in mainline since Rev4 firmware fallbacks to "google,snow"
>> and Rev5 searches for "google,snow-rev5". That way the compatible string
>> could be consistent with the DTS naming and still be able to pack both Rev4
>> and Rev5 FDT in the same FIT image and let the firmware pick the correct FDT.
>>
>>  arch/arm/boot/dts/Makefile                    |   1 +
>>  arch/arm/boot/dts/exynos5250-snow-common.dtsi | 684 ++++++++++++++++++++++++++
>>  arch/arm/boot/dts/exynos5250-snow-rev5.dts    |  47 ++
>>  arch/arm/boot/dts/exynos5250-snow.dts         | 666 +------------------------
>>  4 files changed, 733 insertions(+), 665 deletions(-)
>>  create mode 100644 arch/arm/boot/dts/exynos5250-snow-common.dtsi
>>  create mode 100644 arch/arm/boot/dts/exynos5250-snow-rev5.dts
> 
> Now the exynos5250-snow.dts means in fact Rev4... but there is no
> information in DTS about it. I think adding compatible
> "google,snow-rev4" makes sense:
> 1. For informational purposes (this could be also handled with a comment).
> 2. Later one could decide to switch the default meaning of "google,snow"
> to Rev5 and the real compatible (rev4) will be there already.
> 
> Could you add the new compatible and fix patch issues pointed by Doug?
> 
Documenting for the compatibles would be required even I already applied
its updated patch...

- Kukjin