dt-bindings: mmc: sprd: Add another optional clock documentation

For some Spreadtrum platforms like SC9860 platform, we should enable another
gate clock '2x_enable' to make the SD host controller work well. Thus add
documentation for this optional clock.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-sprd.txt b/Documentation/devicetree/bindings/mmc/sdhci-sprd.txt
index 45c9978..a285c77 100644 (file)
--- a/Documentation/devicetree/bindings/mmc/sdhci-sprd.txt
+++ b/Documentation/devicetree/bindings/mmc/sdhci-sprd.txt
@@ -14,6 +14,7 @@ Required properties:
 - clock-names: Should contain the following:
        "sdio" - SDIO source clock (required)
        "enable" - gate clock which used for enabling/disabling the device (required)
+       "2x_enable" - gate clock controlling the device for some special platforms (optional)
 
 Optional properties:
 - assigned-clocks: the same with "sdio" clock