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mmc: Prevent 1.8V switch for SD hosts that don't support UHS modes.

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commit 4188bba0e9 upstream.

The driver should not try to switch to 1.8V when the SD 3.0 host
controller does not have any UHS capabilities bits set (SDR50, DDR50
or SDR104). See page 72 of "SD Specifications Part A2 SD Host
Controller Simplified Specification Version 3.00" under
"1.8V Signaling Enable". Instead of setting SDR12 and SDR25 in the host
capabilities data structure for all V3.0 host controllers, only set them
if SDR104, SDR50 or DDR50 is set in the host capabilities register. This
will prevent the switch to 1.8V later.

Signed-off-by: Al Cooper <acooper@gmail.com>
Acked-by: Arindam Nath <arindam.nath@amd.com>
Acked-by: Philip Rakity <prakity@marvell.com>
Acked-by: Girish K S <girish.shivananjappa@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Al Cooper
2012-03-16 15:54:17 -04:00
committed by Greg Kroah-Hartman
parent 09e4ad5aa6
commit cfa379de3f
1 changed files with 3 additions and 2 deletions
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5
drivers/mmc/host/sdhci.c
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@@ -2515,8 +2515,9 @@ int sdhci_add_host(struct sdhci_host *host)
mmc_card_is_removable(mmc))
mmc->caps |= MMC_CAP_NEEDS_POLL;
/* UHS-I mode(s) supported by the host controller. */
if (host->version >= SDHCI_SPEC_300)
/* Any UHS-I mode in caps implies SDR12 and SDR25 support. */
if (caps[1] & (SDHCI_SUPPORT_SDR104 | SDHCI_SUPPORT_SDR50 |
SDHCI_SUPPORT_DDR50))
mmc->caps |= MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
/* SDR104 supports also implies SDR50 support */