From: jh80.chung@samsung•com (Jaehoon Chung)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] mmc: dw_mmc: try pick the exact same voltage as vmmc for vqmmc
Date: Fri, 21 Nov 2014 21:29:58 +0900 [thread overview]
Message-ID: <546F3046.30209@samsung.com> (raw)
In-Reply-To: <CAPDyKFrzGfDew0eLLEcA+_iS_mo-O2bFU58fjirfXXA8AJ9UYQ@mail.gmail.com>
On 11/21/2014 09:06 PM, Ulf Hansson wrote:
> [...]
>
>> Sure
>> If the first card is sd2.0 since startup, dw_mci_switch_voltage will not be called,
>
> That can't be right. mmc_power_up() should trigger
> dw_mci_switch_voltage() to be invoked.
Since dw_mci_switch_voltage() is invoked, voltage is changed from 1.8v to 2.7v (minimum value 2.7-3.6v), isn't?
>
>> and card can be identified. But if UHS card is pulgged in first, the vqmmc will be down to 1.8v.
>>
>> when sd2.0 card is pulgged in, mmc core will call dw_mci_switch_voltage to change vqmmc to 3.3v
>> (MMC_SINGLE_VOTAGE_330). So vqmmc will be set 2.7v, if we request 2.7-3.6v.
>>
>> But vmmc is always 3.3v,becuase it be set min_volt = max_volt = 3.3v in dt tables.
vmmc is fixed voltage?
>>
>> So the result:
>> vmmc = 3.3v and vqmmc = 2.7v, and sd2.0 card is failed to identify in my test.
>
> Hmm. I wonder why it works the first time? Could it be that your
> regulator have voltage ramp up time that isn't properly considered?
if oscilloscope can use, can we know more exactly?
Best Regards,
Jaehoon Chung
>
> Kind regards
> Uffe
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next prev parent reply other threads:[~2014-11-21 12:29 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-30 2:21 [PATCH] mmc: dw_mmc: add a quirk for the defferent bit of sdio interrupt Addy Ke
2014-10-30 4:35 ` Jaehoon Chung
2014-10-30 4:41 ` Doug Anderson
2014-10-30 4:49 ` Doug Anderson
2014-10-30 6:54 ` addy ke
2014-10-30 10:50 ` [PATCH] mmc: dw_mmc: add support for the other " Addy Ke
2014-10-30 11:02 ` Jaehoon Chung
2014-10-31 0:46 ` addy ke
2014-10-31 1:14 ` Jaehoon Chung
2014-10-30 11:11 ` Ulf Hansson
2014-10-30 11:17 ` Jaehoon Chung
2014-10-31 0:54 ` addy ke
2014-10-31 3:50 ` [PATCH v2] " Addy Ke
2014-10-31 5:14 ` Doug Anderson
2014-10-31 8:45 ` Jaehoon Chung
2014-10-31 15:55 ` Doug Anderson
2014-10-31 10:43 ` Heiko Stübner
2014-11-03 0:54 ` addy ke
2014-11-03 1:20 ` [PATCH v3] " Addy Ke
2014-11-03 8:59 ` Jaehoon Chung
2014-11-03 10:23 ` addy ke
2014-11-04 2:14 ` Jaehoon Chung
2014-11-03 10:23 ` Heiko Stübner
2014-11-04 2:15 ` Jaehoon Chung
2014-11-04 14:03 ` [PATCH v4] " Addy Ke
2014-11-11 4:02 ` [PATCH] mmc: dw_mmc: try pick the exact same voltage as vmmc for vqmmc Addy Ke
2014-11-11 8:52 ` Ulf Hansson
2014-11-12 18:04 ` Doug Anderson
2014-11-13 2:19 ` addy ke
2014-11-21 12:06 ` Ulf Hansson
2014-11-21 12:29 ` Jaehoon Chung [this message]
2014-11-21 17:42 ` Doug Anderson
2014-11-21 21:04 ` Doug Anderson
2014-11-24 13:29 ` Ulf Hansson
2014-11-25 2:38 ` Addy
2014-11-25 5:36 ` Doug Anderson
2014-11-25 21:11 ` Alexandru Stan
2014-11-25 5:29 ` Doug Anderson
2014-11-13 18:58 ` [PATCH v4] mmc: dw_mmc: add support for the other bit of sdio interrupt Doug Anderson
2014-11-14 13:25 ` Jaehoon Chung
2014-11-19 10:32 ` Ulf Hansson
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