[PATCH 0/3] Add USB DWC3 support for Samsung Exynos8855

[PATCH 0/3] Add USB DWC3 support for Samsung Exynos8855

[Selvarasu Ganesan]

The Samsung Exynos8855 SoC implements a Synopsys DesignWare USB3 DRD
controller. The DWC3 core on the Exynos8855 is instantiated with the
generic dwc3 platform driver using a flattened model, where the
controller is directly addressable without a separate glue layer.

This series adds the device tree binding and platform driver support
for this configuration. The binding follows qcom,snps-dwc3 pattern:
a single node referencing snps,dwc3-common.yaml for shared DWC3
properties, with per-SoC constraints enforced via if-then conditionals.

The MAINTAINERS entry is updated first so that the new binding falls
under the existing ARM/Samsung SoC maintainership.

Selvarasu Ganesan (3):
  MAINTAINERS: add Samsung USB DT binding to ARM/SAMSUNG entry
  dt-bindings: usb: Introduce samsung,snps-dwc3
  usb: dwc3: Add Exynos8855 to the generic platform driver

 .../bindings/usb/samsung,snps-dwc3.yaml       | 98 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 drivers/usb/dwc3/dwc3-generic-plat.c          |  1 +
 3 files changed, 100 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/samsung,snps-dwc3.yaml

-- 
2.17.1

[PATCH 1/3] MAINTAINERS: add Samsung USB DT binding to ARM/SAMSUNG entry

[Selvarasu Ganesan]

Add the Samsung USB devicetree binding file path under the existing
ARM/Samsung SoC maintainership.

Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
---
 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 6008f16ae2ca..c1a466d772a8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3561,6 +3561,7 @@ F:	Documentation/devicetree/bindings/arm/samsung/
 F:	Documentation/devicetree/bindings/hwinfo/samsung,*
 F:	Documentation/devicetree/bindings/power/pd-samsung.yaml
 F:	Documentation/devicetree/bindings/soc/samsung/
+F:	Documentation/devicetree/bindings/usb/samsung,*
 F:	arch/arm/boot/dts/samsung/
 F:	arch/arm/mach-exynos*/
 F:	arch/arm/mach-s3c/
-- 
2.17.1

[PATCH 2/3] dt-bindings: usb: Introduce samsung,snps-dwc3

[Selvarasu Ganesan]

The Samsung Exynos8855 USB glue is not separate from the Synopsys DWC3
core, using a flattened model where the DWC3 controller is directly
addressable rather than nested as a child node of a glue layer.

Describe the Exynos USB block as a single node, referencing the split
out Synopsys DWC3 core properties via snps,dwc3-common.yaml. The new
binding follows the same approach as qcom,snps-dwc3.

A generic fallback compatible "samsung,snps-dwc3" is introduced to
describe this binding, selected by the validator based on the presence
of the fallback string in the compatible list. Future Exynos SoCs
utilizing the same flattened model can be added by extending the
compatible enum with per SoC clock and property constraints.

Co-developed-by: Muhammed Ali <muhammed.ali@samsung.com>
Signed-off-by: Muhammed Ali <muhammed.ali@samsung.com>
Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
---

Krzysztof Kozlowski is added as a maintainer of this YAML binding, as
he is the ARM/Samsung SoC architecture maintainer (ARM/SAMSUNG S3C,
S5P AND EXYNOS ARM ARCHITECTURES) who already maintains Samsung Exynos
DT bindings (e.g. samsung,exynos-dwc3.yaml) and reviews all
Samsung related binding changes. This follows the same convention used
by existing Samsung Exynos DT binding schemas.
---
 .../bindings/usb/samsung,snps-dwc3.yaml       | 98 +++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/samsung,snps-dwc3.yaml

diff --git a/Documentation/devicetree/bindings/usb/samsung,snps-dwc3.yaml b/Documentation/devicetree/bindings/usb/samsung,snps-dwc3.yaml
new file mode 100644
index 000000000000..480308c16f37
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/samsung,snps-dwc3.yaml
@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/samsung,snps-dwc3.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos SoC DWC3 USB Controller
+
+maintainers:
+  - Krzysztof Kozlowski <krzk@kernel.org>
+  - Selvarasu Ganesan <selvarasu.g@samsung.com>
+
+description:
+  Describes the DWC3 USB controller block implemented on Samsung Exynos SoCs.
+
+select:
+  properties:
+    compatible:
+      contains:
+        const: samsung,snps-dwc3
+  required:
+    - compatible
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - samsung,exynos8855-dwc3
+      - const: samsung,snps-dwc3
+
+  reg:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: |
+      Several clocks are used, depending on the variant. Typical ones are:
+       - ref: Reference clock for SOF/ITP generation.
+       - bus: Bus (APB) clock for register access.
+    minItems: 1
+    maxItems: 4
+
+  clock-names:
+    minItems: 1
+    maxItems: 4
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+
+allOf:
+  - $ref: snps,dwc3-common.yaml#
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos8855-dwc3
+    then:
+      properties:
+        clocks:
+          minItems: 2
+          maxItems: 2
+        clock-names:
+          items:
+            - const: ref
+            - const: bus
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    usb@13200000 {
+        compatible = "samsung,exynos8855-dwc3",
+                     "samsung,snps-dwc3";
+        reg = <0x13200000 0x10000>;
+        interrupts = <GIC_SPI 436 IRQ_TYPE_LEVEL_HIGH>;
+        clocks = <&usb_clk 0>,
+                 <&usb_clk 1>;
+        clock-names = "ref", "bus";
+        dr_mode = "peripheral";
+        phys = <&usbdrd_phy 0>;
+        phy-names = "usb2-phy";
+        snps,quirk-frame-length-adjustment = <0x20>;
+        snps,dis-u2-freeclk-exists-quirk;
+        snps,gfladj-refclk-lpm-sel-quirk;
+    };
+...
-- 
2.17.1

[PATCH 3/3] usb: dwc3: Add Exynos8855 to the generic platform driver

[Selvarasu Ganesan]

Add the "samsung,snps-dwc3" compatible string to dwc3-generic-plat so
the Exynos8855 USB3 DWC3 controller can probe through the generic DWC3
platform glue.

The "samsung,snps-dwc3" string is used as a generic fallback to support
any Exynos SoC that utilizes a flattened model instantiation. This
fallback allows multiple Exynos SoCs to be supported by the generic
platform driver simply by adding the fallback compatible to their
respective device tree nodes.

Co-developed-by: Muhammed Ali <muhammed.ali@samsung.com>
Signed-off-by: Muhammed Ali <muhammed.ali@samsung.com>
Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
---
 drivers/usb/dwc3/dwc3-generic-plat.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/dwc3/dwc3-generic-plat.c b/drivers/usb/dwc3/dwc3-generic-plat.c
index ca69ac0eb07c..33a76c37d15d 100644
--- a/drivers/usb/dwc3/dwc3-generic-plat.c
+++ b/drivers/usb/dwc3/dwc3-generic-plat.c
@@ -237,6 +237,7 @@ static const struct of_device_id dwc3_generic_of_match[] = {
 	{ .compatible = "fsl,ls1028a-dwc3", &fsl_ls1028_dwc3},
 	{ .compatible = "eswin,eic7700-dwc3", &eic7700_dwc3},
 	{ .compatible = "starfive,jhb100-dwc3", },
+	{ .compatible = "samsung,snps-dwc3", },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, dwc3_generic_of_match);
-- 
2.17.1