diff options
authorDaniel Drake <dsd@laptop.org>2012-11-25 13:02:54 -0500
committerChris Ball <cjb@laptop.org>2012-12-06 13:55:05 -0500
commit8ed765aac31b473e1881986d9fe2b6386f49f933 (patch)
parent6a66180a252f5856fc25de69c6313831f343f50f (diff)
mmc: dt: add no-1-8-v device tree flag
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, so attempting to switch to the 1.8v level will result in a situation that cannot be recovered from without physically replugging the SD card. Add a device tree flag that can be used on systems like these, and hook it up to the equivalent SDHCI quirk. Signed-off-by: Daniel Drake <dsd@laptop.org> Reviewed-by: Philip Rakity <prakity@nvidia.com> Signed-off-by: Chris Ball <cjb@laptop.org>
2 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index b96e510979b..a591c6741d7 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -21,6 +21,8 @@ Optional properties:
- cd-inverted: when present, polarity on the cd gpio line is inverted
- wp-inverted: when present, polarity on the wp gpio line is inverted
- max-frequency: maximum operating clock frequency
+- no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
+ this system, even if the controller claims it is.
Optional SDIO properties:
- keep-power-in-suspend: Preserves card power during a suspend/resume cycle
diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c
index c6c3b124359..d4283ef5917 100644
--- a/drivers/mmc/host/sdhci-pltfm.c
+++ b/drivers/mmc/host/sdhci-pltfm.c
@@ -78,6 +78,9 @@ void sdhci_get_of_property(struct platform_device *pdev)
if (of_get_property(np, "broken-cd", NULL))
+ if (of_get_property(np, "no-1-8-v", NULL))
+ host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V;
if (of_device_is_compatible(np, "fsl,p2020-rev1-esdhc"))
host->quirks |= SDHCI_QUIRK_BROKEN_DMA;