Jaehoon,

On Mon, Aug 25, 2014 at 1:50 AM, Jaehoon Chung [off-list ref] wrote:

On 08/25/2014 05:13 PM, Ulf Hansson wrote:

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On 22 August 2014 20:27, Sonny Rao [off-list ref] wrote:

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On Fri, Aug 22, 2014 at 8:31 AM, Ulf Hansson [off-list ref] wrote:

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On 22 August 2014 15:47, Yuvaraj Kumar C D [off-list ref] wrote:

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Exynos 5250 and 5420 based boards uses built-in CD# line for card
detection.But unfortunately CD# line is on the same voltage rails
as of I/O voltage rails. When we cut off vqmmc,the consequent card
detection will break in these boards.

I didn't know that use CD# line for card detect.
And if CD# voltage rails and I/O voltage rail are same voltage, it doesn't make sense.
Which card is used with same voltages? (eMMC? SD? SDIO?)

Well, I have checked Exynos5250 and 5420, but it looks like not same rails.

I'm not sure I totally understood what you said.  In my manual I have
a table titled "Table 2-1 Exynos 5420 Pin List".  Look in this table
for XMMC2CDN and XMMC2DATA_0.  Look to the right of the table and
you'll see the power domain.  For both it shows VDDQ_MMC2.  If that
doesn't mean that the two are in the same voltage domain then I don't
know what does.  Can you point to any examples where they have
different voltage domains?

I agree that what exynos does is not sensible, but that's what it is.

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I am not sure I follow here.

Is the card detect mechanism handled internally by the dw_mmc controller?

Yes

What card detect mechanism?

The dw_mmc controller has a way to read the card detect, right?
That's internal to the controller.  The alternative would be to use a
generic GPIO for card detect.