mmc: pwrseq: Document optional clock for the simple power sequence

Some WLAN chips attached to a SDIO interface, need an external clock
to be operational. Since this is very common, extend the simple MMC
power sequence DT binding to support an optional clock.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt b/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt
index eaae652213ae..a462c50f19a8 100644
--- a/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc-pwrseq-simple.txt
@@ -12,6 +12,10 @@ Optional properties:
         at initialization and prior we start the power up procedure of the card.
         They will be de-asserted right after the power has been provided to the
         card.
+- clocks : Must contain an entry for the entry in clock-names.
+  See ../clocks/clock-bindings.txt for details.
+- clock-names : Must include the following entry:
+  "ext_clock" (External clock provided to the card).
 
 Example: