Doug, On 08/27/2014 01:14 PM, Doug Anderson wrote: > Jaehoon, > > On Tue, Aug 26, 2014 at 8:48 PM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote: >> Hi, Doug, >> >> On 08/26/2014 12:25 AM, Doug Anderson wrote: >>> Jaehoon, >>> >>> On Mon, Aug 25, 2014 at 1:50 AM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote: >>>> On 08/25/2014 05:13 PM, Ulf Hansson wrote: >>>>> On 22 August 2014 20:27, Sonny Rao <sonnyrao@xxxxxxxxxxxx> wrote: >>>>>> On Fri, Aug 22, 2014 at 8:31 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote: >>>>>>> On 22 August 2014 15:47, Yuvaraj Kumar C D <yuvaraj.cd@xxxxxxxxx> wrote: >>>>>>>> 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 think you're mis-understanding for it. >> Right, It's described at exynos5420, but it's not connected. > > "It's not connected". What do you mean? If I were to guess I'd say > that on some particular board you're looking at they don't happen to > use the "CD" pin for card detect. If this is what you mean, it > doesn't help me. exynos5420-peach-pit does use the CD pin for card > detect. You can look at the DTS file and confirm it. I didn't know how exynos5420-peach-pit's circuit is configured. But i guess that almost all exynos5 boards are configured with the similar circuit. At Almost all Exynos5 board, CD-pin is used, but not included in Same power domain. (CD-pin is external card-detect pin. - like XEINT_# pin) You mentioned CD# and DATA# lines is used the same power domain, right? In Circuit (not exynos5420-peach-pit), DATA# line and CMD/CLK(vqmmc) is same power supply, and vdd is used other power supply. Not use the CD# pin, used the XEINT_# pin. So i think we don't need to consider the CD#. If exynos5420-peach-pit board is used the CD#-pin, then our discussion can be changed. Your commit message looks like all exynos5250/5420 board are used CD# line. > > ...or are you saying that the CD pin somehow changes voltage domains > when configured as a GPIO? I find that very hard to believe. What > voltage domain does it go to? If it goes to a 1.8V voltage domain > then that would be bad when vqmmc was 3.3V. If it goes to a 3.3V > voltage domain then that would be bad when vqmmc was 1.8V. Remember > that externally we've got a pull up to vqmmc. It is used with XEINT_# pin instead of CD# pin. As i mentioned above, if exynos5420-peach-pit is used CD# line and not used XEINT_# pin, my point is meaningless. :) Is exynos5420-peach-pit board used with CD#pin, not XEINT_# pin? Best Regards, Jaehoon Chung > > Even if somehow magically we can read the card detect pin with vqmmc > off, we have an external pullup on this line that goes directly to the > "vqmmc" power rail. If the vqmmc power rail is off then this external > pull up would not work and would actually act as an external pull down > if you could somehow configure the internal line to be a pullup. > > >> Exynos4 series are also described, but we used the broken card detection scheme and power used one of "always-on" powers. >> Because Card-detection rail need to enable as "always-on". >> >> We don't need to consider this. I checked the circuit, this patch didn't need. >> >> exynos5 also used the gpio-pin for card-detection. And we can use the slot-gpio API. > > When you say "exynos5", what do you mean here? Do you mean the smdk > for 5250, or something else? > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
