new file mode 100644
@@ -0,0 +1,170 @@
+Marvell Xenon SDHCI Controller device tree bindings
+This file documents differences between the core mmc properties
+described by mmc.txt and the properties used by the Xenon implementation.
+
+Multiple SDHCs might be put into a single Xenon IP, to save size and cost.
+Each SDHC is independent and owns independent resources, such as register sets,
+clock and PHY.
+Each SDHC should have an independent device tree node.
+
+Required Properties:
+- compatible: should be one of the following
+ - "marvell,armada-3700-sdhci": For controllers on Armada-3700 SoC.
+ Must provide a second register area and marvell,pad-type.
+ - "marvell,armada-ap806-sdhci": For controllers on Armada AP806.
+ - "marvell,armada-cp110-sdhci": For controllers on Armada CP110.
+
+- clocks:
+ Array of clocks required for SDHC.
+ Require at least input clock for Xenon IP core.
+
+- clock-names:
+ Array of names corresponding to clocks property.
+ The input clock for Xenon IP core should be named as "core".
+
+- reg:
+ * For "marvell,armada-3700-sdhci", two register areas.
+ The first one for Xenon IP register. The second one for the Armada 3700 SoC
+ PHY PAD Voltage Control register.
+ Please follow the examples with compatible "marvell,armada-3700-sdhci"
+ in below.
+ Please also check property marvell,pad-type in below.
+
+ * For other compatible strings, one register area for Xenon IP.
+
+Optional Properties:
+- marvell,xenon-sdhc-id:
+ Indicate the corresponding bit index of current SDHC in
+ SDHC System Operation Control Register Bit[7:0].
+ Set/clear the corresponding bit to enable/disable current SDHC.
+ If Xenon IP contains only one SDHC, this property is optional.
+
+- marvell,xenon-phy-type:
+ Xenon support multiple types of PHYs.
+ To select eMMC 5.1 PHY, set:
+ marvell,xenon-phy-type = "emmc 5.1 phy"
+ eMMC 5.1 PHY is the default choice if this property is not provided.
+ To select eMMC 5.0 PHY, set:
+ marvell,xenon-phy-type = "emmc 5.0 phy"
+
+ All those types of PHYs can support eMMC, SD and SDIO.
+ Please note that this property only presents the type of PHY.
+ It doesn't stand for the entire SDHC type or property.
+ For example, "emmc 5.1 phy" doesn't mean that this Xenon SDHC only
+ supports eMMC 5.1.
+
+- marvell,xenon-phy-znr:
+ Set PHY ZNR value.
+ Only available for eMMC PHY.
+ Valid range = [0:0x1F].
+ ZNR is set as 0xF by default if this property is not provided.
+
+- marvell,xenon-phy-zpr:
+ Set PHY ZPR value.
+ Only available for eMMC PHY.
+ Valid range = [0:0x1F].
+ ZPR is set as 0xF by default if this property is not provided.
+
+- marvell,xenon-phy-nr-success-tun:
+ Set the number of required consecutive successful sampling points
+ used to identify a valid sampling window, in tuning process.
+ Valid range = [1:7].
+ Set as 0x4 by default if this property is not provided.
+
+- marvell,xenon-phy-tun-step-divider:
+ Set the divider for calculating TUN_STEP.
+ Set as 64 by default if this property is not provided.
+
+- marvell,xenon-phy-slow-mode:
+ If this property is selected, transfers will bypass PHY.
+ Only available when bus frequency lower than 55MHz in SDR mode.
+ Disabled by default. Please only try this property if timing issues
+ always occur with PHY enabled in eMMC HS SDR, SD SDR12, SD SDR25,
+ SD Default Speed and HS mode and eMMC legacy speed mode.
+
+- marvell,xenon-tun-count:
+ Xenon SDHC SoC usually doesn't provide re-tuning counter in
+ Capabilities Register 3 Bit[11:8].
+ This property provides the re-tuning counter.
+ If this property is not set, default re-tuning counter will
+ be set as 0x9 in driver.
+
+- marvell,pad-type:
+ Type of Armada 3700 SoC PHY PAD Voltage Controller register.
+ Only valid when "marvell,armada-3700-sdhci" is selected.
+ Two types: "sd" and "fixed-1-8v".
+ If "sd" is selected, SoC PHY PAD is set as 3.3V at the beginning and is
+ switched to 1.8V when later in higher speed mode.
+ If "fixed-1-8v" is selected, SoC PHY PAD is fixed 1.8V, such as for eMMC.
+ Please follow the examples with compatible "marvell,armada-3700-sdhci"
+ in below.
+
+Example:
+- For eMMC:
+
+ sdhci@aa0000 {
+ compatible = "marvell,armada-ap806-sdhci";
+ reg = <0xaa0000 0x1000>;
+ interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
+ clocks = <&emmc_clk>;
+ clock-names = "core";
+ bus-width = <4>;
+ marvell,xenon-phy-slow-mode;
+ marvell,xenon-tun-count = <11>;
+ non-removable;
+ no-sd;
+ no-sdio;
+
+ /* Vmmc and Vqmmc are both fixed */
+ };
+
+- For SD/SDIO:
+
+ sdhci@ab0000 {
+ compatible = "marvell,armada-cp110-sdhci";
+ reg = <0xab0000 0x1000>;
+ interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
+ vqmmc-supply = <&sd_vqmmc_regulator>;
+ vmmc-supply = <&sd_vmmc_regulator>;
+ clocks = <&sdclk>;
+ clock-names = "core";
+ bus-width = <4>;
+ marvell,xenon-tun-count = <9>;
+ };
+
+- For eMMC with compatible "marvell,armada-3700-sdhci":
+
+ sdhci@aa0000 {
+ compatible = "marvell,armada-3700-sdhci";
+ reg = <0xaa0000 0x1000>,
+ <phy_addr 0x4>;
+ interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
+ clocks = <&emmcclk>;
+ clock-names = "core";
+ bus-width = <8>;
+ mmc-ddr-1_8v;
+ mmc-hs400-1_8v;
+ non-removable;
+ no-sd;
+ no-sdio;
+
+ /* Vmmc and Vqmmc are both fixed */
+
+ marvell,pad-type = "fixed-1-8v";
+ };
+
+- For SD/SDIO with compatible "marvell,armada-3700-sdhci":
+
+ sdhci@ab0000 {
+ compatible = "marvell,armada-3700-sdhci";
+ reg = <0xab0000 0x1000>,
+ <phy_addr 0x4>;
+ interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
+ vqmmc-supply = <&sd_regulator>;
+ /* Vmmc is fixed */
+ clocks = <&sdclk>;
+ clock-names = "core";
+ bus-width = <4>;
+
+ marvell,pad-type = "sd";
+ };