diff options
authorJeetesh Burman <>2013-12-16 17:47:43 +0530
committerMatthew Pedro <>2014-05-28 08:46:23 -0700
commit61a7d245ef0bd5d299de2219361799a824ecc18d (patch)
parent8e435e6e4d7155eeffc1fe60ac98b7dab83ed4ec (diff)
mmc: sdhci: add quirk for lack of 1.8v support
The OLPC XO-1.75 laptop includes a SDHCI controller which is 1.8v capable, and it truthfully reports so in its capabilities. This alternate voltage is used for driving new "UHS-I" SD cards at their full speed. However, what the controller doesn't know is that the motherboard physically doesn't have a 1.8v supply available. Add a quirk so that systems such as this one can override disable 1.8v support, adding support for UHS-I cards (by running them at 3.3v). This avoids a problem where the system would first try to run the card at 1.8v, fail, and then not be able to fully reset the card to retry at the normal 3.3v voltage. This is more appropriate than using the MISSING_CAPS quirk, which is intended for cases where the SDHCI controller is actually lying about its capabilities, and would force us to somehow override both caps words from another source. Bug 1402031 Change-Id: I7ca070a13241e6403eb2e243ebbc441a311110bc Signed-off-by: Daniel Drake <> Reviewed-by: Philip Rakity <> Signed-off-by: Chris Ball <> Signed-off-by: Jeetesh Burman <> Reviewed-on: http://git-master/r/346323 Reviewed-by: Matthew Pedro <> Tested-by: Matthew Pedro <>
2 files changed, 9 insertions, 3 deletions
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 3a440dcf0f24..a1c7484371b9 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2658,9 +2658,13 @@ int sdhci_add_host(struct sdhci_host *host)
mmc_card_is_removable(mmc) && !(host->ops->get_cd))
mmc->caps |= MMC_CAP_NEEDS_POLL;
- /* UHS-I mode(s) supported by the host controller. */
- if (host->version >= SDHCI_SPEC_300)
- mmc->caps |= MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
+ if (host->quirks & SDHCI_QUIRK2_NO_1_8_V)
+ else
+ /* UHS-I mode(s) supported by the host controller. */
+ if (host->version >= SDHCI_SPEC_300)
+ mmc->caps |= MMC_CAP_UHS_SDR12 | MMC_CAP_UHS_SDR25;
/* SDR104 supports also implies SDR50 support */
if (caps[1] & SDHCI_SUPPORT_SDR104)
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 5ee48390decc..db86304e1c28 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -93,6 +93,8 @@ struct sdhci_host {
/* Controller doesn't calculate max_discard_to */
+/* The system physically doesn't support 1.8v, even if the host does */
+#define SDHCI_QUIRK2_NO_1_8_V (1ULL<<35)
int irq; /* Device IRQ */
void __iomem *ioaddr; /* Mapped address */