[PATCH v3 0/2] Add USB DWC3 support for Samsung Exynos8855

[PATCH v3 0/2] 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 is the first Samsung Exynos binding using the flattened
representation, and this series adds the device tree binding and
platform driver support for this configuration.

Signed-off-by: Selvarasu Ganesan <selvarasu.g@samsung.com>
---

Changes in v3:
- Drop the MAINTAINERS patch.
- Drop the samsung,snps-dwc3 generic fallback compatible. The binding
  now uses the SoC specific compatible samsung,exynos8855-dwc3 only.
- Binding file is renamed to match the compatible string.
- Remove the "select" from the binding.
- List the clocks (ref, bus) explicitly and drop the redundant if/then
  block.
- Update the driver patch to use the new compatible string.
- Drop the v2 Reviewed-by (Alim Akhtar) and Acked-by (Thinh Nguyen)
  tags as the patches changed. re-requesting them.
- Link to v2:
  https://lore.kernel.org/all/20260916122229.2604003-1-selvarasu.g@samsung.com/

Changes in v2:
- Commit 2/3: Clarify this is the first Samsung Exynos binding using
  the flattened node representation.
- Commit 3/3: Add the compatible entry in alphabetical order in the
  of_match_table.
- Link to v1:
  https://lore.kernel.org/all/20260903071250.3421499-1-selvarasu.g@samsung.com/

Selvarasu Ganesan (2):
  dt-bindings: usb: Add Samsung Exynos8855 DWC3 controller binding
  usb: dwc3: Add Exynos8855 to the generic platform driver

 .../bindings/usb/samsung,exynos8855-dwc3.yaml | 74 +++++++++++++++++++
 drivers/usb/dwc3/dwc3-generic-plat.c          |  5 +-
 2 files changed, 77 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/usb/samsung,exynos8855-dwc3.yaml

-- 
2.17.1

[PATCH v3 1/2] dt-bindings: usb: Add Samsung Exynos8855 DWC3 controller binding

[Selvarasu Ganesan]

Add the Samsung Exynos8855 DWC3 binding using a flattened node
representation, where the DWC3 controller is directly addressable
rather than nested as a child node of a glue layer.

This is the first Samsung Exynos binding using the flattened
representation.

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>
---
 .../bindings/usb/samsung,exynos8855-dwc3.yaml | 74 +++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/samsung,exynos8855-dwc3.yaml

diff --git a/Documentation/devicetree/bindings/usb/samsung,exynos8855-dwc3.yaml b/Documentation/devicetree/bindings/usb/samsung,exynos8855-dwc3.yaml
new file mode 100644
index 000000000000..d8983c310d31
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/samsung,exynos8855-dwc3.yaml
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/samsung,exynos8855-dwc3.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos8855 DWC3 USB controller
+
+maintainers:
+  - Krzysztof Kozlowski <krzk@kernel.org>
+  - Selvarasu Ganesan <selvarasu.g@samsung.com>
+
+description:
+  Describes the DWC3 USB controller block implemented on the Samsung
+  Exynos8855 SoC.
+
+properties:
+  compatible:
+    enum:
+      - samsung,exynos8855-dwc3
+
+  reg:
+    maxItems: 1
+
+  power-domains:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    description: |
+      Two clocks are used:
+       - ref: Reference clock for SOF/ITP generation.
+       - bus: Bus (APB) clock for register access.
+    minItems: 2
+    maxItems: 2
+
+  clock-names:
+    items:
+      - const: ref
+      - const: bus
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - interrupts
+
+allOf:
+  - $ref: snps,dwc3-common.yaml#
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    usb@13200000 {
+        compatible = "samsung,exynos8855-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

Re: [PATCH v3 1/2] dt-bindings: usb: Add Samsung Exynos8855 DWC3 controller binding

[Krzysztof Kozlowski]

On Fri, Oct 23, 2026 at 06:45:00PM +0530, Selvarasu Ganesan wrote:
> +title: Samsung Exynos8855 DWC3 USB controller
> +
> +maintainers:
> +  - Krzysztof Kozlowski <krzk@kernel.org>
> +  - Selvarasu Ganesan <selvarasu.g@samsung.com>
> +
> +description:
> +  Describes the DWC3 USB controller block implemented on the Samsung
> +  Exynos8855 SoC.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - samsung,exynos8855-dwc3
> +
> +  reg:
> +    maxItems: 1
> +
> +  power-domains:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1

interrupts go after clocks, power-domains after interrupts.

> +
> +  clocks:
> +    description: |
> +      Two clocks are used:
> +       - ref: Reference clock for SOF/ITP generation.
> +       - bus: Bus (APB) clock for register access.
> +    minItems: 2
> +    maxItems: 2

Instead replace all this with listing items with description. Don't
repeat constraints in free form text.

items:
  - description:
  - description:


> +
> +  clock-names:
> +    items:
> +      - const: ref
> +      - const: bus
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - interrupts

Here you have correct order.

Best regards,
Krzysztof

Re: [PATCH v3 1/2] dt-bindings: usb: Add Samsung Exynos8855 DWC3 controller binding

[Selvarasu Ganesan]

On 10/26/2026 3:14 PM, Krzysztof Kozlowski wrote:
> On Fri, Oct 23, 2026 at 06:45:00PM +0530, Selvarasu Ganesan wrote:
>> +title: Samsung Exynos8855 DWC3 USB controller
>> +
>> +maintainers:
>> +  - Krzysztof Kozlowski <krzk@kernel.org>
>> +  - Selvarasu Ganesan <selvarasu.g@samsung.com>
>> +
>> +description:
>> +  Describes the DWC3 USB controller block implemented on the Samsung
>> +  Exynos8855 SoC.
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - samsung,exynos8855-dwc3
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  power-domains:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
> interrupts go after clocks, power-domains after interrupts.


Hi Krzysztof,

Thanks for your comments.
My bad, will update in the next version.


>
>> +
>> +  clocks:
>> +    description: |
>> +      Two clocks are used:
>> +       - ref: Reference clock for SOF/ITP generation.
>> +       - bus: Bus (APB) clock for register access.
>> +    minItems: 2
>> +    maxItems: 2
> Instead replace all this with listing items with description. Don't
> repeat constraints in free form text.
>
> items:
>    - description:
>    - description:
Sure, will update the clocks as below in the next version,

     clocks:
       items:
         - description: Reference clock for SOF/ITP generation.
         - description: Bus (APB) clock for register access.

Thanks,
Selva
>> +
>> +  clock-names:
>> +    items:
>> +      - const: ref
>> +      - const: bus
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - clocks
>> +  - clock-names
>> +  - interrupts
> Here you have correct order.
>
> Best regards,
> Krzysztof

Re: [PATCH v3 1/2] dt-bindings: usb: Add Samsung Exynos8855 DWC3 controller binding

[Krzysztof Kozlowski]

On Fri, Oct 23, 2026 at 06:45:00PM +0530, Selvarasu Ganesan wrote:
> Add the Samsung Exynos8855 DWC3 binding using a flattened node
> representation, where the DWC3 controller is directly addressable
> rather than nested as a child node of a glue layer.
> 
> This is the first Samsung Exynos binding using the flattened
> representation.

Ah and:
A nit, subject: drop second/last, redundant "binding". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v7.1-rc7/source/Documentation/devicetree/bindings/submitting-patches.rst#L23

Best regards,
Krzysztof

Re: [PATCH v3 1/2] dt-bindings: usb: Add Samsung Exynos8855 DWC3 controller binding

[Selvarasu Ganesan]

On 10/26/2026 3:14 PM, Krzysztof Kozlowski wrote:
> On Fri, Oct 23, 2026 at 06:45:00PM +0530, Selvarasu Ganesan wrote:
>> Add the Samsung Exynos8855 DWC3 binding using a flattened node
>> representation, where the DWC3 controller is directly addressable
>> rather than nested as a child node of a glue layer.
>>
>> This is the first Samsung Exynos binding using the flattened
>> representation.
> Ah and:
> A nit, subject: drop second/last, redundant "binding". The
> "dt-bindings" prefix is already stating that these are bindings.
> See also:
> https://protect2.fireeye.com/v1/url?k=f1571c7b-aecc251e-f1569734-000babff32e3-08400c25edf5bcfb&q=1&e=549cd4c8-34f1-4b98-afc6-3f62b054ef3c&u=https%3A%2F%2Felixir.bootlin.com%2Flinux%2Fv7.1-rc7%2Fsource%2FDocumentation%2Fdevicetree%2Fbindings%2Fsubmitting-patches.rst%23L23
>
> Best regards,
> Krzysztof


Hi Krzysztof,

Thanks for pointing this out. Sure, will drop the redundant "binding" in 
the next version.

Thanks,
Selva

[PATCH v3 2/2] usb: dwc3: Add Exynos8855 to the generic platform driver

[Selvarasu Ganesan]

Add the "samsung,exynos8855-dwc3" compatible string to dwc3-generic-plat
so the Exynos8855 DWC3 controller can probe through the generic DWC3
platform glue. While at it, alphabetically reorder the existing entries.

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 | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/dwc3-generic-plat.c b/drivers/usb/dwc3/dwc3-generic-plat.c
index ca69ac0eb07c..d57496716204 100644
--- a/drivers/usb/dwc3/dwc3-generic-plat.c
+++ b/drivers/usb/dwc3/dwc3-generic-plat.c
@@ -232,10 +232,11 @@ static const struct dwc3_generic_config eic7700_dwc3 =  {
 };
 
 static const struct of_device_id dwc3_generic_of_match[] = {
+	{ .compatible = "eswin,eic7700-dwc3", &eic7700_dwc3},
+	{ .compatible = "fsl,ls1028a-dwc3", &fsl_ls1028_dwc3},
+	{ .compatible = "samsung,exynos8855-dwc3", },
 	{ .compatible = "spacemit,k1-dwc3", &spacemit_k1_dwc3},
 	{ .compatible = "spacemit,k3-dwc3", },
-	{ .compatible = "fsl,ls1028a-dwc3", &fsl_ls1028_dwc3},
-	{ .compatible = "eswin,eic7700-dwc3", &eic7700_dwc3},
 	{ .compatible = "starfive,jhb100-dwc3", },
 	{ /* sentinel */ }
 };
-- 
2.17.1

Re: [PATCH v3 2/2] usb: dwc3: Add Exynos8855 to the generic platform driver

[Krzysztof Kozlowski]

On Fri, Oct 23, 2026 at 06:45:01PM +0530, Selvarasu Ganesan wrote:
> Add the "samsung,exynos8855-dwc3" compatible string to dwc3-generic-plat
> so the Exynos8855 DWC3 controller can probe through the generic DWC3
> platform glue. While at it, alphabetically reorder the existing entries.
> 
> 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 | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)

Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Best regards,
Krzysztof