scsi: ufs: dt-bindings: Document Rockchip UFS host controller

Document Rockchip UFS host controller for RK3576 SoC.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Link: https://lore.kernel.org/r/1738736156-119203-2-git-send-email-shawn.lin@rock-chips.com
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml b/Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml
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+++ b/Documentation/devicetree/bindings/ufs/rockchip,rk3576-ufshc.yaml
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+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/ufs/rockchip,rk3576-ufshc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Rockchip UFS Host Controller
+
+maintainers:
+  - Shawn Lin <shawn.lin@rock-chips.com>
+
+allOf:
+  - $ref: ufs-common.yaml
+
+properties:
+  compatible:
+    const: rockchip,rk3576-ufshc
+
+  reg:
+    maxItems: 5
+
+  reg-names:
+    items:
+      - const: hci
+      - const: mphy
+      - const: hci_grf
+      - const: mphy_grf
+      - const: hci_apb
+
+  clocks:
+    maxItems: 4
+
+  clock-names:
+    items:
+      - const: core
+      - const: pclk
+      - const: pclk_mphy
+      - const: ref_out
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 4
+
+  reset-names:
+    items:
+      - const: biu
+      - const: sys
+      - const: ufs
+      - const: grf
+
+  reset-gpios:
+    maxItems: 1
+    description: |
+      GPIO specifiers for host to reset the whole UFS device including PHY and
+      memory. This gpio is active low and should choose the one whose high output
+      voltage is lower than 1.5V based on the UFS spec.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - clock-names
+  - interrupts
+  - power-domains
+  - resets
+  - reset-names
+  - reset-gpios
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/rockchip,rk3576-cru.h>
+    #include <dt-bindings/reset/rockchip,rk3576-cru.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/power/rockchip,rk3576-power.h>
+    #include <dt-bindings/pinctrl/rockchip.h>
+    #include <dt-bindings/gpio/gpio.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        ufshc: ufshc@2a2d0000 {
+            compatible = "rockchip,rk3576-ufshc";
+            reg = <0x0 0x2a2d0000 0x0 0x10000>,
+                  <0x0 0x2b040000 0x0 0x10000>,
+                  <0x0 0x2601f000 0x0 0x1000>,
+                  <0x0 0x2603c000 0x0 0x1000>,
+                  <0x0 0x2a2e0000 0x0 0x10000>;
+            reg-names = "hci", "mphy", "hci_grf", "mphy_grf", "hci_apb";
+            clocks = <&cru ACLK_UFS_SYS>, <&cru PCLK_USB_ROOT>, <&cru PCLK_MPHY>,
+                     <&cru CLK_REF_UFS_CLKOUT>;
+            clock-names = "core", "pclk", "pclk_mphy", "ref_out";
+            interrupts = <GIC_SPI 361 IRQ_TYPE_LEVEL_HIGH>;
+            power-domains = <&power RK3576_PD_USB>;
+            resets = <&cru SRST_A_UFS_BIU>, <&cru SRST_A_UFS_SYS>, <&cru SRST_A_UFS>,
+                     <&cru SRST_P_UFS_GRF>;
+            reset-names = "biu", "sys", "ufs", "grf";
+            reset-gpios = <&gpio4 RK_PD0 GPIO_ACTIVE_LOW>;
+        };
+    };