[PATCH v2 2/9] dt-bindings: mmc: cdns,sdhci: add SD6HC support and PHY properties

[Tanmay Kathpalia]

Extend the Cadence SDHCI binding to support the sixth-generation SD6HC
controller. Add the cdns,sd6hc compatible string with two named clocks
(ciu and biu) and three SD6HC-specific PHY timing properties for iocell
input/output delay and delay element size.

Add the altr,agilex5-sd6hc compatible string with three named reset
lines from the Altera HPS Reset Manager. Introduce per-variant
constraints so SD6HC and SD4HC each enforce their own clock, reset, and
PHY property requirements independently.

Signed-off-by: Tanmay Kathpalia <tanmay.kathpalia@xxxxxxxxxx>
---
 .../devicetree/bindings/mmc/cdns,sdhci.yaml   | 122 ++++++++++++++++--
 1 file changed, 111 insertions(+), 11 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
index 6c7317d13aa6..edd96e1d2bdc 100644
--- a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
@@ -4,21 +4,29 @@
 $id: http://devicetree.org/schemas/mmc/cdns,sdhci.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Cadence SD/SDIO/eMMC Host Controller (SD4HC)
+title: Cadence SD/SDIO/eMMC Host Controller (SD4HC and SD6HC)
 
 maintainers:
   - Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
+  - Tanmay Kathpalia <tanmay.kathpalia@xxxxxxxxxx>
 
 properties:
   compatible:
-    items:
-      - enum:
-          - amd,pensando-elba-sd4hc
-          - microchip,mpfs-sd4hc
-          - microchip,pic64gx-sd4hc
-          - mobileye,eyeq-sd4hc
-          - socionext,uniphier-sd4hc
-      - const: cdns,sd4hc
+    oneOf:
+      - description: Cadence SD4HC controller
+        items:
+          - enum:
+              - amd,pensando-elba-sd4hc
+              - microchip,mpfs-sd4hc
+              - microchip,pic64gx-sd4hc
+              - mobileye,eyeq-sd4hc
+              - socionext,uniphier-sd4hc
+          - const: cdns,sd4hc
+      - description: Cadence SD6HC controller
+        items:
+          - enum:
+              - altr,agilex5-sd6hc
+          - const: cdns,sd6hc
 
   reg:
     minItems: 1
@@ -28,10 +36,12 @@ properties:
     maxItems: 1
 
   clocks:
-    maxItems: 1
+    minItems: 1
+    maxItems: 2
 
   resets:
-    maxItems: 1
+    minItems: 1
+    maxItems: 3
 
   # PHY DLL input delays:
   # They are used to delay the data valid window, and align the window to
@@ -115,6 +125,25 @@ properties:
     minimum: 0
     maximum: 0x7f
 
+  # SD6HC PHY timing properties:
+  cdns,iocell-input-delay:
+    description: Input delay across IO cells in picoseconds
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 20000   # 20 ns
+
+  cdns,iocell-output-delay:
+    description: Output delay across IO cells in picoseconds
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 0
+    maximum: 20000   # 20 ns
+
+  cdns,delay-element:
+    description: Delay element size in picoseconds
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1
+    maximum: 1000    # 1 ns
+
 required:
   - compatible
   - reg
@@ -139,6 +168,77 @@ allOf:
         reg:
           maxItems: 1
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: cdns,sd6hc
+    then:
+      description: SD6HC variant - use IO-cell and delay element properties
+      properties:
+        clocks:
+          minItems: 2
+          maxItems: 2
+        clock-names:
+          items:
+            - const: ciu
+            - const: biu
+        dma-coherent: true
+        iommus:
+          maxItems: 1
+        cdns,phy-input-delay-sd-highspeed: false
+        cdns,phy-input-delay-legacy: false
+        cdns,phy-input-delay-sd-uhs-sdr12: false
+        cdns,phy-input-delay-sd-uhs-sdr25: false
+        cdns,phy-input-delay-sd-uhs-sdr50: false
+        cdns,phy-input-delay-sd-uhs-ddr50: false
+        cdns,phy-input-delay-mmc-highspeed: false
+        cdns,phy-input-delay-mmc-ddr: false
+        cdns,phy-dll-delay-sdclk: false
+        cdns,phy-dll-delay-sdclk-hsmmc: false
+        cdns,phy-dll-delay-strobe: false
+      required:
+        - clock-names
+
+  # The Cadence SD6HC IP has per-clock-domain reset inputs, but the specific
+  # reset lines exposed here ("sdhc-reset", "combophy", "sdmmc-ocp") are
+  # provided by the Altera HPS Reset Manager and reflect the Agilex5 SoC
+  # integration.
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: altr,agilex5-sd6hc
+    then:
+      properties:
+        resets:
+          minItems: 3
+          maxItems: 3
+        reset-names:
+          items:
+            - const: sdhc-reset
+            - const: combophy
+            - const: sdmmc-ocp
+      required:
+        - resets
+        - reset-names
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: cdns,sd4hc
+    then:
+      description: SD4HC variant - use legacy DLL delay properties
+      properties:
+        clocks:
+          maxItems: 1
+        resets:
+          maxItems: 1
+        cdns,iocell-input-delay: false
+        cdns,iocell-output-delay: false
+        cdns,delay-element: false
+
 unevaluatedProperties: false
 
 examples:
-- 
2.43.7