* [PATCH v4 2/2] usb: dwc3: dwc3-generic-plat: Add Renesas R-Car Gen5 DWC3 xHCI USB controller glue
2026-08-19 5:00 [PATCH v4 1/2] dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller Marek Vasut
@ 2026-08-19 5:00 ` Marek Vasut
2026-08-19 5:08 ` sashiko-bot
2026-08-19 5:08 ` [PATCH v4 1/2] dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller sashiko-bot
1 sibling, 1 reply; 4+ messages in thread
From: Marek Vasut @ 2026-08-19 5:00 UTC (permalink / raw)
To: linux-usb
Cc: Thanh Quan, Marek Vasut, Conor Dooley, Geert Uytterhoeven,
Greg Kroah-Hartman, Krzysztof Kozlowski, Rob Herring,
Thinh Nguyen, devicetree, linux-kernel, linux-renesas-soc
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
---
drivers/usb/dwc3/dwc3-generic-plat.c | 60 ++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/drivers/usb/dwc3/dwc3-generic-plat.c b/drivers/usb/dwc3/dwc3-generic-plat.c
index ca69ac0eb07ce..dec89b068291a 100644
--- a/drivers/usb/dwc3/dwc3-generic-plat.c
+++ b/drivers/usb/dwc3/dwc3-generic-plat.c
@@ -71,6 +71,60 @@ 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;
+
+ /*
+ * Controller can be limited to USB 2 via optional maximum-speed DT
+ * property. If the DT property is not present, default to maximum
+ * controller capabilities.
+ */
+ 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 +285,17 @@ 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
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v4 1/2] dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller
2026-08-19 5:00 [PATCH v4 1/2] dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller Marek Vasut
2026-08-19 5:00 ` [PATCH v4 2/2] usb: dwc3: dwc3-generic-plat: Add Renesas R-Car Gen5 DWC3 xHCI USB controller glue Marek Vasut
@ 2026-08-19 5:08 ` sashiko-bot
1 sibling, 0 replies; 4+ messages in thread
From: sashiko-bot @ 2026-08-19 5:08 UTC (permalink / raw)
To: Marek Vasut; +Cc: wsa+renesas, robh, conor+dt, devicetree
Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Missing `phys` and `phy-names` property constraints in the local schema, allowing device trees with up to 19 PHYs to pass validation.
--
--- Patch [1]: [PATCH v4 1/2] dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller ---
commit cb2d4b4bfe0dea655c7acecc9fb3e13518b6d5fb
Author: Marek Vasut <marek.vasut+renesas@mailbox.org>
dt-bindings: usb: dwc3: Document Renesas R-Car Gen5 DWC3 xHCI USB controller
This commit documents the device tree bindings for the Renesas R-Car Gen5
DWC3 xHCI USB controller. It adds a new YAML schema referencing the generic
DWC3 common schema and defines local hardware constraints.
> 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
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/usb/renesas,rcar-gen5-dwc3.yaml
> @@ -0,0 +1,68 @@
[ ... ]
> +allOf:
> + - $ref: snps,dwc3-common.yaml#
> +
> +properties:
> + compatible:
> + items:
> + - const: renesas,r8a78000-dwc3
> + - const: renesas,rcar-gen5-dwc3
[Severity: Low]
Should phys and phy-names constraints be included in this local properties
block?
The commit log mentions dropping generic phys/phy-names because of the
generic snps,dwc3-common.yaml reference. However, the generic schema permits
up to 19 PHYs.
Without local constraints (like maxItems: 2) specified in this block, the
schema would allow device trees with 3 or more PHYs to silently pass
validation, even though the hardware only supports 1 or 2.
> +
> + reg:
> + maxItems: 2
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260819050109.681890-1-marek.vasut+renesas@mailbox.org?part=1
^ permalink raw reply [flat|nested] 4+ messages in thread