dt-bindings: mmc: Add bindings for Intel Thunder Bay SoC

Add documentation for Arasan SDHCI controller in Thunder Bay SOC.
Signed-off-by: Rashmi A <rashmi.a@intel.com>
Link: https://lore.kernel.org/r/20210829182443.30802-3-rashmi.a@intel.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Documentation/devicetree/bindings/mmc/arasan,sdhci.yaml

@@ -88,6 +88,12 @@ properties:
         description:
           For this device it is strongly suggested to include
           arasan,soc-ctl-syscon.
+      - items:
+          - const: intel,thunderbay-sdhci-5.1   # Intel Thunder Bay eMMC PHY
+          - const: arasan,sdhci-5.1
+        description:
+          For this device it is strongly suggested to include
+          clock-output-names and '#clock-cells'.
 
   reg:
     maxItems: 1
@@ -301,3 +307,22 @@ examples:
                    <&scmi_clk KEEM_BAY_PSS_SD0>;
           arasan,soc-ctl-syscon = <&sd0_phy_syscon>;
     };
+
+  - |
+    #define EMMC_XIN_CLK
+    #define EMMC_AXI_CLK
+    #define TBH_PSS_EMMC_RST_N
+    mmc@80420000 {
+          compatible = "intel,thunderbay-sdhci-5.1", "arasan,sdhci-5.1";
+          interrupts = <GIC_SPI 714 IRQ_TYPE_LEVEL_HIGH>;
+          reg = <0x80420000 0x400>;
+          clocks = <&scmi_clk EMMC_XIN_CLK>,
+                   <&scmi_clk EMMC_AXI_CLK>;
+          clock-names = "clk_xin", "clk_ahb";
+          phys = <&emmc_phy>;
+          phy-names = "phy_arasan";
+          assigned-clocks = <&scmi_clk EMMC_XIN_CLK>;
+          clock-output-names = "emmc_cardclock";
+          resets = <&rst_pss1 TBH_PSS_EMMC_RST_N>;
+          #clock-cells = <0x0>;
+    };