[PATCH v3 2/3] usb: dwc3: add common driver to support flattened DT

Ze Huang
2025-05-17T19:20:06Z

To support flattened dwc3 dt model and drop the glue layer, introduce the
`dwc3-common` driver. This enables direct binding of the DWC3 core driver
and offers an alternative to the existing glue driver `dwc3-of-simple`.

Signed-off-by: Ze Huang <huangze@whut.edu.cn>
---
drivers/usb/dwc3/Kconfig | 9 ++
drivers/usb/dwc3/Makefile | 1 +
drivers/usb/dwc3/dwc3-common.c | 191 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 201 insertions(+)

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index 310d182e10b50b253d7e5a51674806e6ec442a2a..852f94f906e4f339dcbb562e1ce708409ba77b76 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -118,6 +118,15 @@ config USB_DWC3_OF_SIMPLE
Currently supports Xilinx and Qualcomm DWC USB3 IP.
Say 'Y' or 'M' if you have one such device.

+config USB_DWC3_COMMON
+ tristate "DWC3 Platform common Driver"
+ depends on OF && COMMON_CLK
+ default USB_DWC3
+ help
+ Support USB3 functionality in simple SoC integrations.
+ Currently supports SpacemiT DWC USB3 IP.
+ Say 'Y' or 'M' if you have one such device.
+
config USB_DWC3_ST
tristate "STMicroelectronics Platforms"
depends on (ARCH_STI || COMPILE_TEST) && OF
diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index 830e6c9e5fe073c1f662ce34b6a4a2da34c407a2..ad1b0705c4d464f19e79ed0c3c63d942446e4742 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -57,3 +57,4 @@ obj-$(CONFIG_USB_DWC3_IMX8MP) += dwc3-imx8mp.o
obj-$(CONFIG_USB_DWC3_XILINX) += dwc3-xilinx.o
obj-$(CONFIG_USB_DWC3_OCTEON) += dwc3-octeon.o
obj-$(CONFIG_USB_DWC3_RTK) += dwc3-rtk.o
+obj-$(CONFIG_USB_DWC3_COMMON) += dwc3-common.o
diff --git a/drivers/usb/dwc3/dwc3-common.c b/drivers/usb/dwc3/dwc3-common.c
new file mode 100644
index 0000000000000000000000000000000000000000..afd9a7bec14b68dfd4f2353d714041882660a1a4
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-common.c
@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * dwc3-common.c - DesignWare USB3 common driver
+ *
+ * Copyright (C) 2025 Ze Huang <huangze@whut.edu.cn>
+ *
+ * Inspired by dwc3-qcom.c and dwc3-of-simple.c
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include "glue.h"
+
+struct dwc3_common {
+ struct device *dev;
+ struct dwc3 dwc;
+ struct clk_bulk_data *clks;
+ int num_clocks;
+ struct reset_control *resets;
+};
+
+static int dwc3_common_probe(struct platform_device *pdev)
+{
+ struct dwc3_probe_data probe_data = {};
+ struct device *dev = &pdev->dev;
+ struct dwc3_common *dwc3c;
+ struct resource *res;
+ int ret;
+
+ dwc3c = devm_kzalloc(dev, sizeof(*dwc3c), GFP_KERNEL);
+ if (!dwc3c)
+ return -ENOMEM;
+
+ dwc3c->dev = dev;
+
+ platform_set_drvdata(pdev, dwc3c);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "missing memory resource\n");
+ return -ENODEV;
+ }
+
+ dwc3c->resets = of_reset_control_array_get_optional_exclusive(dev->of_node);
+ if (IS_ERR(dwc3c->resets))
+ return dev_err_probe(dev, PTR_ERR(dwc3c->resets), "failed to get reset\n");
+
+ ret = reset_control_assert(dwc3c->resets);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to assert reset\n");
+
+ usleep_range(10, 1000);
+
+ ret = reset_control_deassert(dwc3c->resets);
+ if (ret) {
+ dev_err(dev, "failed to deassert reset\n");
+ goto reset_assert;
+ }
+
+ ret = clk_bulk_get_all(dwc3c->dev, &dwc3c->clks);
+ if (ret < 0) {
+ dev_err(dev, "failed to get clocks\n");
+ goto reset_assert;
+ }
+
+ dwc3c->num_clocks = ret;
+
+ ret = clk_bulk_prepare_enable(dwc3c->num_clocks, dwc3c->clks);
+ if (ret) {
+ dev_err(dev, "failed to enable clocks\n");
+ goto reset_assert;
+ }
+
+ dwc3c->dwc.dev = dev;
+ probe_data.dwc = &dwc3c->dwc;
+ probe_data.res = res;
+ probe_data.ignore_clocks_and_resets = true;
+ ret = dwc3_core_probe(&probe_data);
+ if (ret) {
+ dev_err(dev, "failed to register DWC3 Core\n");
+ goto clk_disable;
+ }
+
+ return 0;
+
+clk_disable:
+ clk_bulk_disable_unprepare(dwc3c->num_clocks, dwc3c->clks);
+ clk_bulk_put_all(dwc3c->num_clocks, dwc3c->clks);
+
+reset_assert:
+ reset_control_assert(dwc3c->resets);
+
+ return ret;
+}
+
+static void dwc3_common_remove(struct platform_device *pdev)
+{
+ struct dwc3_common *dwc3c = platform_get_drvdata(pdev);
+
+ dwc3_core_remove(&dwc3c->dwc);
+
+ clk_bulk_disable_unprepare(dwc3c->num_clocks, dwc3c->clks);
+ clk_bulk_put_all(dwc3c->num_clocks, dwc3c->clks);
+
+ reset_control_assert(dwc3c->resets);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int dwc3_common_suspend(struct device *dev)
+{
+ struct dwc3_common *dwc3c = dev_get_drvdata(dev);
+ int ret;
+
+ ret = dwc3_pm_suspend(&dwc3c->dwc);
+ if (ret)
+ return ret;
+
+ clk_bulk_disable_unprepare(dwc3c->num_clocks, dwc3c->clks);
+
+ return 0;
+}
+
+static int dwc3_common_resume(struct device *dev)
+{
+ struct dwc3_common *dwc3c = dev_get_drvdata(dev);
+ int ret;
+
+ ret = clk_bulk_prepare_enable(dwc3c->num_clocks, dwc3c->clks);
+ if (ret)
+ return ret;
+
+ ret = dwc3_pm_resume(&dwc3c->dwc);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int dwc3_common_runtime_suspend(struct device *dev)
+{
+ struct dwc3_common *dwc3c = dev_get_drvdata(dev);
+
+ return dwc3_runtime_suspend(&dwc3c->dwc);
+}
+
+static int dwc3_common_runtime_resume(struct device *dev)
+{
+ struct dwc3_common *dwc3c = dev_get_drvdata(dev);
+
+ return dwc3_runtime_resume(&dwc3c->dwc);
+}
+
+static int dwc3_common_runtime_idle(struct device *dev)
+{
+ struct dwc3_common *dwc3c = dev_get_drvdata(dev);
+
+ return dwc3_runtime_idle(&dwc3c->dwc);
+}
+
+static const struct dev_pm_ops dwc3_common_dev_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(dwc3_common_suspend, dwc3_common_resume)
+ RUNTIME_PM_OPS(dwc3_common_runtime_suspend, dwc3_common_runtime_resume,
+ dwc3_common_runtime_idle)
+};
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct of_device_id dwc3_common_of_match[] = {
+ { .compatible = "spacemit,k1-dwc3", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dwc3_common_of_match);
+
+static struct platform_driver dwc3_common_driver = {
+ .probe = dwc3_common_probe,
+ .remove = dwc3_common_remove,
+ .driver = {
+ .name = "dwc3-common",
+ .of_match_table = dwc3_common_of_match,
+#ifdef CONFIG_PM_SLEEP
+ .pm = &dwc3_common_dev_pm_ops,
+#endif /* CONFIG_PM_SLEEP */
+ },
+};
+module_platform_driver(dwc3_common_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("DesignWare USB3 common driver");

--
2.49.0