Re: [PATCH 1/2] mmc: sdhci: Added set_power sdhci_ops handler.

Felipe Tonello
2013-05-24T22:12:48Z

Hi all,

On Thu, May 23, 2013 at 9:02 PM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
> On 05/23/2013 04:25 PM, Guennadi Liakhovetski wrote:
>> On Wed, 22 May 2013, Felipe Ferreri Tonello wrote:
>>
>>> Hi Guennadi,
>>>
>>> On Wednesday, May 22, 2013 10:30:40 PM Guennadi Liakhovetski wrote:
>>>> On Wed, 22 May 2013, Felipe F. Tonello wrote:
>>>>> From: "Felipe F. Tonello" <eu@felipetonello.com>
>>>>>
>>>>> This is useful for power managment purposes if a sdhci child host wants to
>>>>> turn off some other peripheral also.
>>>>
>>>> Sorry, could you elaborate a bit? In what situations is it exactly useful?
>>>> And why cannot the regulator API be used there?
>>>
>>> Sorry about that.
>>>
>>> One example that I can think of is when you have a wifi module connected as a
>>> mmc card via sdio. So you can register a callback function in your machine
>>> source code to turn on/off the wifi module based on the mmc host power.
>>
>> Ok, understand. Your second patch in this series adds such a callback in
>> your SDHCI host driver and there it just calls a platform callback. I
>> don't think this is a good idea. First, we want to go away from platform
>> callbacks, because they are incompatible with DT. Second, because the
>> proper solution IMHO would be for your platform to export a regulator, and
>> the SDHCI core driver already includes regulator support.
> We can use the regulator framework.
> i think this callback function didn't need.
>

Ok, thanks for the feed back. Just to get things clear, is this
implementation using regulator framework already done?

BR,

Felipe

> Best Regards,
> Jaehoon Chung
>>
>>> I've seen this implementation in others mmc hosts, such as omap.
>>
>> Which, however, doesn't yet mean, it's a good idea :)
>>
>> Thanks
>> Guennadi
>> ---
>> Guennadi Liakhovetski, Ph.D.
>> Freelance Open-Source Software Developer
>> http://www.open-technology.de/
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>