[PATCH v4 1/8] dt-bindings: mmc: add Cadence SD6HC binding

[Tanmay Kathpalia <tanmay.kathpalia@altera.com>]

Cadence SD6HC is a sixth-generation SD/SDIO/eMMC host controller with a
dedicated Cadence Combo PHY interface. It uses separate card-interface
(CIU/SDMCLK) and bus-interface (BIU) clock domains.

PHY timing depends on board IO-cell input/output delays and the DLL
delay-element size. On Altera Agilex5, the SDHC, Combo PHY, and SDMMC
OCP bridge are each reset independently through the HPS Reset Manager.

Signed-off-by: Tanmay Kathpalia <tanmay.kathpalia@altera.com>
---
 .../devicetree/bindings/mmc/cdns,sd6hc.yaml   | 102 ++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml

diff --git a/Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml b/Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml
new file mode 100644
index 000000000000..302b5f90d803
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/cdns,sd6hc.yaml
@@ -0,0 +1,102 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mmc/cdns,sd6hc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Cadence SD6HC SD/SDIO/eMMC Host Controller
+
+maintainers:
+  - Tanmay Kathpalia <tanmay.kathpalia@altera.com>
+
+description:
+  Cadence SD6HC is a sixth-generation SD/SDIO/eMMC host controller with an
+  interface to a Cadence Combo PHY. The controller has separate card interface
+  and bus interface clock domains.
+
+properties:
+  compatible:
+    items:
+      - const: altr,agilex5-sd6hc
+      - const: cdns,sd6hc
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: card interface unit (CIU / SDMCLK) clock
+      - description: bus interface unit (BIU) clock
+
+  clock-names:
+    items:
+      - const: ciu
+      - const: biu
+
+  resets:
+    items:
+      - description: SDHC controller reset
+      - description: Combo PHY reset
+      - description: SDMMC OCP/AXI reset
+
+  reset-names:
+    items:
+      - const: sdhc-reset
+      - const: combophy
+      - const: sdmmc-ocp
+
+  iommus:
+    maxItems: 1
+
+  dma-coherent: true
+
+  cdns,iocell-input-delay-ps:
+    description:
+      Input delay across the IO cells, used for SD6HC PHY timing calculations.
+    minimum: 0
+    maximum: 20000
+
+  cdns,iocell-output-delay-ps:
+    description:
+      Output delay across the IO cells, used for SD6HC PHY timing calculations.
+    minimum: 0
+    maximum: 20000
+
+  cdns,delay-element-ps:
+    description:
+      DLL delay element size, used for SD6HC PHY timing calculations.
+    minimum: 1
+    maximum: 1000
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - resets
+  - reset-names
+
+allOf:
+  - $ref: sdhci-common.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    mmc@10808000 {
+        compatible = "altr,agilex5-sd6hc", "cdns,sd6hc";
+        reg = <0x10808000 0x1000>;
+        interrupts = <GIC_SPI 96 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&clkmgr 0>, <&clkmgr 1>;
+        clock-names = "ciu", "biu";
+        resets = <&rst 0>, <&rst 1>, <&rst 2>;
+        reset-names = "sdhc-reset", "combophy", "sdmmc-ocp";
+        iommus = <&smmu 5>;
+        dma-coherent;
+    };
-- 
2.43.7