From 52dbd6e1a2a687e66181cf2b10b4d720f308f3fb Mon Sep 17 00:00:00 2001 From: Al Cooper Date: Fri, 16 Mar 2012 15:54:17 -0400 Subject: [PATCH] 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 Acked-by: Arindam Nath Acked-by: Philip Rakity Acked-by: Girish K S Signed-off-by: Chris Ball --- drivers/mmc/host/sdhci.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 8262cadfdab77..9aa77f3f04a86 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 */ -- 2.39.5