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authorAl Cooper <acooper@gmail.com>2012-03-16 15:54:17 -0400
committerChris Ball <cjb@laptop.org>2012-04-05 20:32:32 -0400
commit4188bba0e9e7ba58d231b528df495666f2742b74 (patch)
tree062ef9f10f7c55c7784dd3dc8ed059cab00ba7c8 /drivers/mmc
parent79263f33b0f3abe26d74a66824b457b94bdbef9f (diff)
downloadop-kernel-dev-4188bba0e9e7ba58d231b528df495666f2742b74.zip
op-kernel-dev-4188bba0e9e7ba58d231b528df495666f2742b74.tar.gz
mmc: Prevent 1.8V switch for SD hosts that don't support UHS modes.
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>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/host/sdhci.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 8262cad..9aa77f3 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2782,8 +2782,9 @@ 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 */
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