Re: [PATCH v2 1/2] Documentation: mmc: add description for power-delay-ms

[Shawn Lin <shawn.lin@rock-chips.com>]

On 2018/5/2 20:46, Ulf Hansson wrote:
> On 28 April 2018 at 03:11, Shawn Lin <shawn.lin@rock-chips.com> wrote:
>> Hi Rob and Ulf,
>>
>> On 2018/4/28 2:54, Rob Herring wrote:
>>>
>>> On Mon, Apr 23, 2018 at 04:10:29PM +0800, Shawn Lin wrote:
>>
>>
>> ...
>>
>>>> +- power-delay-ms: Tunable delay waiting for I/O signalling and card
>>>> power supply
>>>> +  to be stable. Default to 10ms if no available.
>>>
>>>
>>> How long do you need? Would changing the default to say 20ms work and
>>> still be short enough others don't care?
>>
>>
>> It varies from board-2-board, but my boards only need 2ms or less. The
>> hard-coded 10ms was increased from 2ms since 2009, just for fixing one
>> board. And nobody complained 10ms is too short(including me), so it's
>> fine for everybody probably. However, nobody complained it's toooo long
>> as well, expect me, so my best guess is either others don't care it at
>> all, or haven't noticed it. So the intention for this patch, is to save
>> the unnecessary waste for the boot-time sensitive environment, by
>> reducing the delay but don't break anything else.
>>
>>
>>>
>>> Can we use the same property as the mmc pwrseq binding defines:
>>> post-power-on-delay-ms
>>
>>
>> I'm fine with using post-power-on-delay-ms, but it depends on whether
>> using pwrseq_simple. So I need add parsing it in two places for
>> different prupose. Is it ok, or better idea?
> 
> I don't think the parsing is an issue, but that we need to allow two
> different descriptions of the same property name may be a bit
> confusing.

> I would rather keep them separate, but I have no strong onion.
> 

I also would like to keep the separate. Rob, any suggestion? :)

> Kind regards
> Uffe
> 
> 
>