usb: dwc3: add generic driver to support flattened

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

Acked-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Signed-off-by: Ze Huang <huang.ze@linux.dev>
Link: https://lore.kernel.org/r/20250913-dwc3_generic-v8-2-b50f81f05f95@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250913-dwc3_generic-v8-2-b50f81f05f95@linux.dev

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index 310d182e10b50b253d7e5a51674806e6ec442a2a..4925d15084f816d3ff92059b476ebcc799b56b51 100644 (file)
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -189,4 +189,15 @@ config USB_DWC3_RTK
          or dual-role mode.
          Say 'Y' or 'M' if you have such device.
 
+config USB_DWC3_GENERIC_PLAT
+       tristate "DWC3 Generic Platform Driver"
+       depends on OF && COMMON_CLK
+       default USB_DWC3
+       help
+         Support USB3 functionality in simple SoC integrations.
+         Currently supports SpacemiT DWC USB3. Platforms using
+         dwc3-of-simple can easily switch to dwc3-generic by flattening
+         the dwc3 child node in the device tree.
+         Say 'Y' or 'M' here if your platform integrates DWC3 in a similar way.
+
 endif

diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index 830e6c9e5fe073c1f662ce34b6a4a2da34c407a2..96469e48ff9d189cc8d0b65e65424eae2158bcfe 100644 (file)
--- 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_GENERIC_PLAT)    += dwc3-generic-plat.o

diff --git a/drivers/usb/dwc3/dwc3-generic-plat.c b/drivers/usb/dwc3/dwc3-generic-plat.c
new file mode 100644 (file)
index 0000000..d96b205
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-generic-plat.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * dwc3-generic-plat.c - DesignWare USB3 generic platform driver
+ *
+ * Copyright (C) 2025 Ze Huang <huang.ze@linux.dev>
+ *
+ * Inspired by dwc3-qcom.c and dwc3-of-simple.c
+ */
+
+#include <linux/clk.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include "glue.h"
+
+struct dwc3_generic {
+       struct device           *dev;
+       struct dwc3             dwc;
+       struct clk_bulk_data    *clks;
+       int                     num_clocks;
+       struct reset_control    *resets;
+};
+
+#define to_dwc3_generic(d) container_of((d), struct dwc3_generic, dwc)
+
+static void dwc3_generic_reset_control_assert(void *data)
+{
+       reset_control_assert(data);
+}
+
+static int dwc3_generic_probe(struct platform_device *pdev)
+{
+       struct dwc3_probe_data probe_data = {};
+       struct device *dev = &pdev->dev;
+       struct dwc3_generic *dwc3g;
+       struct resource *res;
+       int ret;
+
+       dwc3g = devm_kzalloc(dev, sizeof(*dwc3g), GFP_KERNEL);
+       if (!dwc3g)
+               return -ENOMEM;
+
+       dwc3g->dev = dev;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res) {
+               dev_err(&pdev->dev, "missing memory resource\n");
+               return -ENODEV;
+       }
+
+       dwc3g->resets = devm_reset_control_array_get_optional_exclusive(dev);
+       if (IS_ERR(dwc3g->resets))
+               return dev_err_probe(dev, PTR_ERR(dwc3g->resets), "failed to get resets\n");
+
+       ret = reset_control_assert(dwc3g->resets);
+       if (ret)
+               return dev_err_probe(dev, ret, "failed to assert resets\n");
+
+       /* Not strict timing, just for safety */
+       udelay(2);
+
+       ret = reset_control_deassert(dwc3g->resets);
+       if (ret)
+               return dev_err_probe(dev, ret, "failed to deassert resets\n");
+
+       ret = devm_add_action_or_reset(dev, dwc3_generic_reset_control_assert, dwc3g->resets);
+       if (ret)
+               return ret;
+
+       ret = devm_clk_bulk_get_all_enabled(dwc3g->dev, &dwc3g->clks);
+       if (ret < 0)
+               return dev_err_probe(dev, ret, "failed to get clocks\n");
+
+       dwc3g->num_clocks = ret;
+       dwc3g->dwc.dev = dev;
+       probe_data.dwc = &dwc3g->dwc;
+       probe_data.res = res;
+       probe_data.ignore_clocks_and_resets = true;
+       ret = dwc3_core_probe(&probe_data);
+       if (ret)
+               return dev_err_probe(dev, ret, "failed to register DWC3 Core\n");
+
+       return 0;
+}
+
+static void dwc3_generic_remove(struct platform_device *pdev)
+{
+       struct dwc3 *dwc = platform_get_drvdata(pdev);
+       struct dwc3_generic *dwc3g = to_dwc3_generic(dwc);
+
+       dwc3_core_remove(dwc);
+
+       clk_bulk_disable_unprepare(dwc3g->num_clocks, dwc3g->clks);
+}
+
+static int dwc3_generic_suspend(struct device *dev)
+{
+       struct dwc3 *dwc = dev_get_drvdata(dev);
+       struct dwc3_generic *dwc3g = to_dwc3_generic(dwc);
+       int ret;
+
+       ret = dwc3_pm_suspend(dwc);
+       if (ret)
+               return ret;
+
+       clk_bulk_disable_unprepare(dwc3g->num_clocks, dwc3g->clks);
+
+       return 0;
+}
+
+static int dwc3_generic_resume(struct device *dev)
+{
+       struct dwc3 *dwc = dev_get_drvdata(dev);
+       struct dwc3_generic *dwc3g = to_dwc3_generic(dwc);
+       int ret;
+
+       ret = clk_bulk_prepare_enable(dwc3g->num_clocks, dwc3g->clks);
+       if (ret)
+               return ret;
+
+       ret = dwc3_pm_resume(dwc);
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
+static int dwc3_generic_runtime_suspend(struct device *dev)
+{
+       return dwc3_runtime_suspend(dev_get_drvdata(dev));
+}
+
+static int dwc3_generic_runtime_resume(struct device *dev)
+{
+       return dwc3_runtime_resume(dev_get_drvdata(dev));
+}
+
+static int dwc3_generic_runtime_idle(struct device *dev)
+{
+       return dwc3_runtime_idle(dev_get_drvdata(dev));
+}
+
+static const struct dev_pm_ops dwc3_generic_dev_pm_ops = {
+       SYSTEM_SLEEP_PM_OPS(dwc3_generic_suspend, dwc3_generic_resume)
+       RUNTIME_PM_OPS(dwc3_generic_runtime_suspend, dwc3_generic_runtime_resume,
+                      dwc3_generic_runtime_idle)
+};
+
+static const struct of_device_id dwc3_generic_of_match[] = {
+       { .compatible = "spacemit,k1-dwc3", },
+       { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, dwc3_generic_of_match);
+
+static struct platform_driver dwc3_generic_driver = {
+       .probe          = dwc3_generic_probe,
+       .remove         = dwc3_generic_remove,
+       .driver         = {
+               .name   = "dwc3-generic-plat",
+               .of_match_table = dwc3_generic_of_match,
+               .pm     = pm_ptr(&dwc3_generic_dev_pm_ops),
+       },
+};
+module_platform_driver(dwc3_generic_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("DesignWare USB3 generic platform driver");