[PATCH V2 1/5] dt-bindings: mmc: document the stm32 sdmmc bindings

[Ludovic Barre <ludovic.Barre@st.com>]

From: Ludovic Barre <ludovic.barre@st.com>

Document the binding for stm32 sdmmc controller.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
---
 .../devicetree/bindings/mmc/st,stm32-sdmmc.txt     | 35 ++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt

diff --git a/Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt b/Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt
new file mode 100644
index 0000000..74d0bff
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/st,stm32-sdmmc.txt
@@ -0,0 +1,35 @@
+* STMicroelectronics STM32 SDMMC controller
+
+The highspeed MMC host controller on STM32 soc family
+provides an interface for MMC, SD and SDIO types of memory cards.
+
+This file documents differences between the core properties described
+by mmc.txt and the properties used by the sdmmc driver.
+
+Required properties:
+ - compatible: Should be "st,stm32h7-sdmmc"
+ - reg: mmc controller base registers
+ - interrupts: Should contain the interrupt number
+ - clocks: Should contain phandle for the clock feeding the controller
+ - resets: Should contain phandle for the reset feeding the controller
+
+Optional property:
+- st,dir-output-high: Allow to select direction polarity of external voltage
+  transceiver (which manage data and command direction).
+  if set: Voltage transceiver IOs are driven as output when direction signals are high,
+  else: Voltage transceiver IOs are driven as output when direction signals are low.
+- st,neg-edge: generate data & command on sdmmc clock falling edge
+- st,use-ckin: use sdmmc_ckin pin from an external driver to sample
+  the receive data (example: with voltage switch transceiver).
+
+Example:
+	sdmmc1: mmc@52007000 {
+		compatible = "st,stm32h7-sdmmc";
+		reg = <0x52007000 0x1000>;
+		interrupts = <49>;
+		clocks = <&rcc SDMMC1_CK>;
+		resets = <&rcc SDMMC1_R>;
+		bus-width = <4>;
+		cap-sd-highspeed;
+		cap-mmc-highspeed;
+	};
-- 
2.7.4