[PATCH v6 1/2] dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller

[PATCH v6 1/2] dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller

[Marek Vasut]

The Renesas R-Car Gen5 SoC contains multiple instances of DWC3 USB
controller with glue logic wrapper around them. Document the glue
logic and DWC3 controller.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
---
V2: Rework to use flat bindings for generic plat driver
V3: - Support one or two PHYs to correctly describe the hardware
    - Make maximum-speed optional
V4: - Use ref: snps,dwc3-common.yaml and drop generic dr_mode/maximum-speed/phys/phy-names
    - Switch to unevaluatedProperties: false
V5: - Limit maximum PHY count to 2
V6: No change
---
 .../bindings/usb/renesas,rcar-gen5-dwc3.yaml  | 76 +++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/usb/renesas,rcar-gen5-dwc3.yaml

diff --git a/Documentation/devicetree/bindings/usb/renesas,rcar-gen5-dwc3.yaml b/Documentation/devicetree/bindings/usb/renesas,rcar-gen5-dwc3.yaml
new file mode 100644
index 0000000000000..c8a770d7e0241
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/renesas,rcar-gen5-dwc3.yaml
@@ -0,0 +1,76 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/renesas,rcar-gen5-dwc3.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas R-Car Gen5 DWC3 xHCI USB controller
+
+maintainers:
+  - Marek Vasut <marek.vasut+renesas@mailbox.org>
+
+allOf:
+  - $ref: snps,dwc3-common.yaml#
+
+properties:
+  compatible:
+    items:
+      - const: renesas,r8a78000-dwc3
+      - const: renesas,rcar-gen5-dwc3
+
+  reg:
+    maxItems: 2
+
+  reg-names:
+    items:
+      - const: dwc3
+      - const: glue
+
+  clocks:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  phys:
+    minItems: 1
+    maxItems: 2
+
+  phy-names:
+    minItems: 1
+    maxItems: 2
+
+  power-domains:
+    maxItems: 1
+
+  resets:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - clocks
+  - interrupts
+  - phys
+  - phy-names
+  - power-domains
+  - resets
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+
+    usb@c8800000 {
+        compatible = "renesas,r8a78000-dwc3", "renesas,rcar-gen5-dwc3";
+        reg = <0xc8800000 0x100000>, <0xc9c54000 0x2000>;
+        reg-names = "dwc3", "glue";
+        clocks = <&scmi_clk 336>;
+        interrupts = <GIC_SPI 795 IRQ_TYPE_LEVEL_HIGH>;
+        phys = <&usb30_phy>, <&mp_phy 2>;
+        phy-names = "usb2-phy", "usb3-phy";
+        power-domains = <&scmi_devpd 16>;
+        resets = <&scmi_reset 336>;
+    };
-- 
2.53.0

[PATCH v6 2/2] usb: dwc3: dwc3-generic-plat: Add Renesas R-Car Gen5 DWC3 xHCI USB controller glue

[Marek Vasut]

From: Thanh Quan <thanh.quan.xn@renesas.com>

The Renesas R-Car Gen5 SoC contains multiple instances of DWC3 USB
controller with glue logic wrapper around them. Extend the generic
DWC3 platform driver with Renesas R-Car Gen5 glue logic specifics.

Signed-off-by: Thanh Quan <thanh.quan.xn@renesas.com>
Co-developed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: Conor Dooley <conor+dt@kernel.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Krzysztof Kozlowski <krzk+dt@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Cc: devicetree@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-renesas-soc@vger.kernel.org
Cc: linux-usb@vger.kernel.org
---
V2: Extend dwc3-generic-plat driver instead
V3: Handle maximum-speed as optional property, test for USB 3 PHY
    non-presence to determine whether the controller is USB 2 only,
    consider optional maximum-speed DT property, but if it is missing
    then default to maximum controller capabilities based on the
    presence of PHY phandles.
V4: No change
V5: - Drop superfluous code comment
    - Drop duplicate speed >= USB_SPEED_LOW test
V6: Reinstate speed >= USB_SPEED_LOW test to avoid triggering on USB_SPEED_UNKNOWN
---
 drivers/usb/dwc3/dwc3-generic-plat.c | 55 ++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-generic-plat.c b/drivers/usb/dwc3/dwc3-generic-plat.c
index ca69ac0eb07ce..e8586c40d5006 100644
--- a/drivers/usb/dwc3/dwc3-generic-plat.c
+++ b/drivers/usb/dwc3/dwc3-generic-plat.c
@@ -71,6 +71,55 @@ static int dwc3_eic7700_init(struct dwc3_generic *dwc3g)
 	return 0;
 }
 
+static int dwc3_renesas_rcar_gen5_init(struct dwc3_generic *dwc3g)
+{
+	struct device *dev = dwc3g->dev;
+	struct platform_device *pdev = to_platform_device(dev);
+	enum usb_device_speed speed = usb_get_maximum_speed(dev);
+	bool usb2only = false;
+	void __iomem *glue;
+
+	/* Wireless USB is not supported */
+	if (speed == USB_SPEED_WIRELESS)
+		return dev_err_probe(dev, -EINVAL, "Wireless USB not supported\n");
+
+	/* No USB 3 PHY in DT means this is surely USB 2 controller */
+	if (device_property_match_string(dev, "phy-names", "usb3-phy") < 0)
+		usb2only = true;
+
+	if (speed >= USB_SPEED_LOW && speed <= USB_SPEED_HIGH)
+		usb2only = true;
+
+	glue = devm_platform_ioremap_resource_byname(pdev, "glue");
+	if (IS_ERR(glue))
+		return PTR_ERR(glue);
+
+	/*
+	 * The datasheet describes initialization procedure without full
+	 * information about the registers. Therefore, the source code is
+	 * based on the bare metal code shared by the board team.
+	 */
+	writew(0x211, glue + 0x26);
+
+	/* USB2 does need additional register programming. */
+	if (!usb2only)
+		return 0;
+
+	writew(0x11, glue + 0x81c);
+	writew(0x0, glue + 0x81a);
+	writew(0x1, glue + 0x802);
+
+	usleep_range(10000, 20000);
+
+	writew(0x0, glue + 0x802);
+	writew(0x1, glue + 0x2a);
+	writew(0x1, glue + 0x81a);
+
+	usleep_range(10000, 20000);
+
+	return 0;
+}
+
 static int dwc3_spacemit_k1_init(struct dwc3_generic *dwc3g)
 {
 	struct device *dev = dwc3g->dev;
@@ -231,11 +280,17 @@ static const struct dwc3_generic_config eic7700_dwc3 =  {
 	.properties = DWC3_DEFAULT_PROPERTIES,
 };
 
+static const struct dwc3_generic_config renesas_rcar_gen5_dwc3 = {
+	.init = dwc3_renesas_rcar_gen5_init,
+	.properties = DWC3_DEFAULT_PROPERTIES,
+};
+
 static const struct of_device_id dwc3_generic_of_match[] = {
 	{ .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 = "renesas,rcar-gen5-dwc3", &renesas_rcar_gen5_dwc3},
 	{ .compatible = "starfive,jhb100-dwc3", },
 	{ /* sentinel */ }
 };
-- 
2.53.0

Re: [PATCH v6 2/2] usb: dwc3: dwc3-generic-plat: Add Renesas R-Car Gen5 DWC3 xHCI USB controller glue

[Krishna Kurapati]

On 8/29/2026 12:11 AM, Marek Vasut wrote:
> From: Thanh Quan <thanh.quan.xn@renesas.com>
> 
> The Renesas R-Car Gen5 SoC contains multiple instances of DWC3 USB
> controller with glue logic wrapper around them. Extend the generic
> DWC3 platform driver with Renesas R-Car Gen5 glue logic specifics.
> 
> Signed-off-by: Thanh Quan <thanh.quan.xn@renesas.com>
> Co-developed-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
> ---

[...]

> diff --git a/drivers/usb/dwc3/dwc3-generic-plat.c b/drivers/usb/dwc3/dwc3-generic-plat.c
> index ca69ac0eb07ce..e8586c40d5006 100644
> --- a/drivers/usb/dwc3/dwc3-generic-plat.c
> +++ b/drivers/usb/dwc3/dwc3-generic-plat.c
> @@ -71,6 +71,55 @@ static int dwc3_eic7700_init(struct dwc3_generic *dwc3g)
>   	return 0;
>   }
>   
> +static int dwc3_renesas_rcar_gen5_init(struct dwc3_generic *dwc3g)
> +{
> +	struct device *dev = dwc3g->dev;
> +	struct platform_device *pdev = to_platform_device(dev);
> +	enum usb_device_speed speed = usb_get_maximum_speed(dev);
> +	bool usb2only = false;
> +	void __iomem *glue;
> +
> +	/* Wireless USB is not supported */
> +	if (speed == USB_SPEED_WIRELESS)
> +		return dev_err_probe(dev, -EINVAL, "Wireless USB not supported\n");
> +
> +	/* No USB 3 PHY in DT means this is surely USB 2 controller */
> +	if (device_property_match_string(dev, "phy-names", "usb3-phy") < 0)
> +		usb2only = true;
> +

Why not just set the maximum-speed property to "high-speed" instead of 
checking for "usb3-phy". That would be more clean.

> +	if (speed >= USB_SPEED_LOW && speed <= USB_SPEED_HIGH)
> +		usb2only = true;

And this check can be removed as well if we use "maximum-speed" property 
in DT.

> +
> +	glue = devm_platform_ioremap_resource_byname(pdev, "glue");
> +	if (IS_ERR(glue))
> +		return PTR_ERR(glue);
> +
> +	/*
> +	 * The datasheet describes initialization procedure without full
> +	 * information about the registers. Therefore, the source code is
> +	 * based on the bare metal code shared by the board team.
> +	 */
> +	writew(0x211, glue + 0x26);
> +
> +	/* USB2 does need additional register programming. */
> +	if (!usb2only)
> +		return 0;
> +
> +	writew(0x11, glue + 0x81c);
> +	writew(0x0, glue + 0x81a);
> +	writew(0x1, glue + 0x802);
> +
> +	usleep_range(10000, 20000);
> +
> +	writew(0x0, glue + 0x802);
> +	writew(0x1, glue + 0x2a);
> +	writew(0x1, glue + 0x81a);
> +
> +	usleep_range(10000, 20000);
> +

Use #defines for register offsets and register values like in 
dwc3_eic7700_init.

Regards,
Krishna,

Re: [PATCH v6 2/2] usb: dwc3: dwc3-generic-plat: Add Renesas R-Car Gen5 DWC3 xHCI USB controller glue

[Marek Vasut]

On 8/29/26 6:19 PM, Krishna Kurapati wrote:

Hi,

>> +static int dwc3_renesas_rcar_gen5_init(struct dwc3_generic *dwc3g)
>> +{
>> +    struct device *dev = dwc3g->dev;
>> +    struct platform_device *pdev = to_platform_device(dev);
>> +    enum usb_device_speed speed = usb_get_maximum_speed(dev);
>> +    bool usb2only = false;
>> +    void __iomem *glue;
>> +
>> +    /* Wireless USB is not supported */
>> +    if (speed == USB_SPEED_WIRELESS)
>> +        return dev_err_probe(dev, -EINVAL, "Wireless USB not 
>> supported\n");
>> +
>> +    /* No USB 3 PHY in DT means this is surely USB 2 controller */
>> +    if (device_property_match_string(dev, "phy-names", "usb3-phy") < 0)
>> +        usb2only = true;
>> +
> 
> Why not just set the maximum-speed property to "high-speed" instead of 
> checking for "usb3-phy". That would be more clean.

Please see 1/2, maximum-speed DT property and the presence of the 
usb3-phy are both optional, hence this code. Also, this was discussed in 
previous version 2 of this patchset already.

>> +    if (speed >= USB_SPEED_LOW && speed <= USB_SPEED_HIGH)
>> +        usb2only = true;
> 
> And this check can be removed as well if we use "maximum-speed" property 
> in DT.

Please see above.

>> +
>> +    glue = devm_platform_ioremap_resource_byname(pdev, "glue");
>> +    if (IS_ERR(glue))
>> +        return PTR_ERR(glue);
>> +
>> +    /*
>> +     * The datasheet describes initialization procedure without full
>> +     * information about the registers. Therefore, the source code is
>> +     * based on the bare metal code shared by the board team.
>> +     */
>> +    writew(0x211, glue + 0x26);
>> +
>> +    /* USB2 does need additional register programming. */
>> +    if (!usb2only)
>> +        return 0;
>> +
>> +    writew(0x11, glue + 0x81c);
>> +    writew(0x0, glue + 0x81a);
>> +    writew(0x1, glue + 0x802);
>> +
>> +    usleep_range(10000, 20000);
>> +
>> +    writew(0x0, glue + 0x802);
>> +    writew(0x1, glue + 0x2a);
>> +    writew(0x1, glue + 0x81a);
>> +
>> +    usleep_range(10000, 20000);
>> +
> 
> Use #defines for register offsets and register values like in 
> dwc3_eic7700_init.

Please see the comment above this section, it clarifies why the magic 
numbers, and it was discussed in previous version 1 of this patchset too.