On Mon, Oct 28, 2013 at 8:12 AM, Kukjin Kim <kgene.kim@xxxxxxxxxxx> wrote:
> On 10/28/13 08:15, Olof Johansson wrote:
>>
>> On Sun, Oct 27, 2013 at 10:36 PM, Jingoo Han<jg1.han@xxxxxxxxxxx> wrote:
>>>
>>> On Monday, October 28, 2013 1:52 PM, Olof Johansson wrote:
>>>>
>>>> On Wed, Sep 4, 2013 at 11:08 PM, Jingoo Han<jg1.han@xxxxxxxxxxx> wrote:
>>>>>
>>>>> Disable PCIe for SD5v1 board, because there is no PCIe slot
>>>>> on SD5v1 board.
>>>>>
>>>>> Signed-off-by: Jingoo Han<jg1.han@xxxxxxxxxxx>
>>>>> ---
>>>>> Tested on SD5v1 board.
>>>>>
>>>>> arch/arm/boot/dts/exynos5440-sd5v1.dts | 7 +++++++
>>>>> 1 file changed, 7 insertions(+)
>>>>>
>>>>> diff --git a/arch/arm/boot/dts/exynos5440-sd5v1.dts
>>>>> b/arch/arm/boot/dts/exynos5440-sd5v1.dts
>>>>> index 5b22508..78a239d 100644
>>>>> --- a/arch/arm/boot/dts/exynos5440-sd5v1.dts
>>>>> +++ b/arch/arm/boot/dts/exynos5440-sd5v1.dts
>>>>> @@ -36,4 +36,11 @@
>>>>> status = "disabled";
>>>>> };
>>>>>
>>>>> + pcie@290000 {
>>>>> + status = "disabled";
>>>>> + };
>>>>> +
>>>>> + pcie@2a0000 {
>>>>> + status = "disabled";
>>>>> + };
>>>>> };
>>>>
>>>>
>>>> Usually IP blocks like these are always left disabled in the dtsi, and
>>>> explicitly _enabled_ in the DTS on boards that make use of that part
>>>> of the chip.
>>>> So the real solution here should be to move the disabling to the 5440
>>>> .dtsi instead.
>>>
>>>
>>> OK, right.
>>> Thank you for your guidance.
>>>
>>> Then, do you mean the following?
>>> If it is right, I will send the v2 patch.
>>
>>
>> Yes, exactly!
>>
>
> Hmm...I thought both ways (#1 disabling something in soc dt, enabling in
> board dt if required, #2 enabling in soc dt, disabling in board dt if
> required) are possible but I have no strong objection with your suggestion.
> In addition, just one way is more clear to us :)
>
> OK, I will keep the way for Samsung stuff.
It varies, in some cases it makes sense to make the default enabled
and just disable where needed, for example for entirely on-chip IP
blocks.
For things like PCI-e, where different board manufacturers might
choose to use it or not, it seems that keeping disabled by default is
sensible.
-Olof
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