| Message ID | 20121125180255.DB8ADFAD06@dev.laptop.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On Sun, Nov 25 2012, Daniel Drake wrote: > 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> Thanks, pushed to mmc-next for 3.8. - Chris.
diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt index 8e2e0ba..3f13702 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. Example: diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c index 2716445..0a16534 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)) host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION; + 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;
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> --- Documentation/devicetree/bindings/mmc/mmc.txt | 2 ++ drivers/mmc/host/sdhci-pltfm.c | 3 +++ 2 files changed, 5 insertions(+)