[PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver

Roy Luo posted 2 patches 2 weeks ago
There is a newer version of this series
[PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Roy Luo 2 weeks ago
Add support for the DWC3 USB controller found on Google Tensor G5
(codename: laguna). The controller features dual-role functionality
and hibernation.

The primary focus is implementing hibernation support in host mode,
enabling the controller to enter a low-power state (D3). This is
particularly relevant during system power state transition and
runtime power management for power efficiency.
Highlights:
- Align suspend callback with dwc3_suspend_common() for deciding
  between a full teardown and hibernation in host mode.
- Integration with `psw` (power switchable) and `top` power domains,
  managing their states and device links to support hibernation.
- A notifier callback dwc3_google_usb_psw_pd_notifier() for
  `psw` power domain events to manage controller state
  transitions to/from D3.
- Coordination of the `non_sticky` reset during power state
  transitions, asserting it on D3 entry and deasserting on D0 entry
  in hibernation scenario.
- Handling of high-speed and super-speed PME interrupts
  that are generated by remote wakeup during hibernation.

Co-developed-by: Joy Chakraborty <joychakr@google.com>
Signed-off-by: Joy Chakraborty <joychakr@google.com>
Co-developed-by: Naveen Kumar <mnkumar@google.com>
Signed-off-by: Naveen Kumar <mnkumar@google.com>
Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Roy Luo <royluo@google.com>
---
 MAINTAINERS                    |   1 +
 drivers/usb/dwc3/Kconfig       |  12 +
 drivers/usb/dwc3/Makefile      |   1 +
 drivers/usb/dwc3/dwc3-google.c | 628 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 642 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 61f5768b31ae31cd72f4c2a3b74398f9473e192b..0659847b980128801b63014de96294c07abca3a0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10666,6 +10666,7 @@ F:	Documentation/devicetree/bindings/usb/google,lga-dwc3.yaml
 F:	arch/arm64/boot/dts/exynos/google/
 F:	drivers/clk/samsung/clk-gs101.c
 F:	drivers/phy/samsung/phy-gs101-ufs.c
+F:	drivers/usb/dwc3/dwc3-google.c
 F:	include/dt-bindings/clock/google,gs101.h
 K:	[gG]oogle.?[tT]ensor
 
diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index 4925d15084f816d3ff92059b476ebcc799b56b51..05e4b7e1d98b1c03c8887c50dfff7e39d365f2a3 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig
@@ -200,4 +200,16 @@ config USB_DWC3_GENERIC_PLAT
 	  the dwc3 child node in the device tree.
 	  Say 'Y' or 'M' here if your platform integrates DWC3 in a similar way.
 
+config USB_DWC3_GOOGLE
+	tristate "Google Platform"
+	depends on ARCH_GOOGLE || COMPILE_TEST
+	help
+	  Support the DesignWare Core USB3 IP found on Google Tensor SoCs,
+	  starting with the G5 generation (Laguna). This driver includes
+	  support for hibernation in host mode.
+	  Say 'Y' or 'M' if you have one such device.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called dwc3-google.ko.
+
 endif
diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index 96469e48ff9d189cc8d0b65e65424eae2158bcfe..cf1cd408d938b3ac26d58b9be7fcc5af3ee82660 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile
@@ -58,3 +58,4 @@ 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
+obj-$(CONFIG_USB_DWC3_GOOGLE)		+= dwc3-google.o
diff --git a/drivers/usb/dwc3/dwc3-google.c b/drivers/usb/dwc3/dwc3-google.c
new file mode 100644
index 0000000000000000000000000000000000000000..a19857bd6b131d841d165717b70f2959b4bac806
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-google.c
@@ -0,0 +1,628 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * dwc3-google.c - Google DWC3 Specific Glue Layer
+ *
+ * Copyright (c) 2025, Google LLC
+ * Author: Roy Luo <royluo@google.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/iopoll.h>
+#include <linux/irq.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_domain.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include "core.h"
+#include "glue.h"
+
+/* HOST CFG registers */
+#define HC_STATUS_OFFSET 0x0
+#define HC_STATUS_CURRENT_POWER_STATE_U2PMU GENMASK(1, 0)
+#define HC_STATUS_CURRENT_POWER_STATE_U3PMU GENMASK(4, 3)
+
+#define HOST_CFG1_OFFSET 0x4
+#define HOST_CFG1_PME_EN BIT(3)
+#define HOST_CFG1_PM_POWER_STATE_REQUEST GENMASK(5, 4)
+#define HOST_CFG1_PM_POWER_STATE_D0 0x0
+#define HOST_CFG1_PM_POWER_STATE_D3 0x3
+
+/* USBINT registers */
+#define USBINT_CFG1_OFFSET 0x0
+#define USBINT_CFG1_USBDRD_PME_GEN_U2P_INTR_MSK BIT(2)
+#define USBINT_CFG1_USBDRD_PME_GEN_U3P_INTR_MSK BIT(3)
+#define USBINT_CFG1_USBDRD_PME_GEN_U2P_INTR_INT_EN BIT(8)
+#define USBINT_CFG1_USBDRD_PME_GEN_U3P_INTR_INT_EN BIT(9)
+#define USBINT_CFG1_USBDRD_PME_GEN_U2_INTR_CLR BIT(14)
+#define USBINT_CFG1_USBDRD_PME_GEN_U3_INTR_CLR BIT(15)
+
+#define USBINT_STATUS_OFFSET 0x4
+#define USBINT_STATUS_USBDRD_PME_GEN_U2P_INTR_STS_RAW BIT(2)
+#define USBINT_STATUS_USBDRD_PME_GEN_U3P_INTR_STS_RAW BIT(3)
+
+#define USBCS_TOP_CTRL_CFG1_OFFSET 0xc
+#define USBCS_TOP_CTRL_CFG1_USB2ONLY_MODE BIT(5)
+
+#define DWC3_GOOGLE_MAX_RESETS	4
+
+struct dwc3_google {
+	struct device		*dev;
+	struct dwc3		dwc;
+	struct clk_bulk_data	*clks;
+	int			num_clks;
+	struct reset_control_bulk_data rsts[DWC3_GOOGLE_MAX_RESETS];
+	int			num_rsts;
+	struct reset_control	*non_sticky_rst;
+	struct device		*usb_psw_pd;
+	struct device_link	*usb_psw_pd_dl;
+	struct notifier_block	usb_psw_pd_nb;
+	struct device		*usb_top_pd;
+	struct device_link	*usb_top_pd_dl;
+	struct regmap		*usb_cfg_regmap;
+	unsigned int		host_cfg_offset;
+	unsigned int		usbint_cfg_offset;
+	int			hs_pme_irq;
+	int			ss_pme_irq;
+	bool			is_usb2only;
+	bool			is_hibernation;
+};
+
+#define to_dwc3_google(d) container_of_const((d), struct dwc3_google, dwc)
+
+static int dwc3_google_rst_init(struct dwc3_google *google)
+{
+	int ret;
+
+	google->num_rsts = 4;
+	google->rsts[0].id = "non_sticky";
+	google->rsts[1].id = "sticky";
+	google->rsts[2].id = "drd_bus";
+	google->rsts[3].id = "top";
+
+	ret = devm_reset_control_bulk_get_exclusive(google->dev,
+						    google->num_rsts,
+						    google->rsts);
+
+	if (ret < 0)
+		return ret;
+
+	google->non_sticky_rst = google->rsts[0].rstc;
+
+	return 0;
+}
+
+static int dwc3_google_set_pmu_state(struct dwc3_google *google, int state)
+{
+	u32 reg;
+	int ret;
+
+	regmap_read(google->usb_cfg_regmap,
+		    google->host_cfg_offset + HOST_CFG1_OFFSET, &reg);
+
+	reg &= ~HOST_CFG1_PM_POWER_STATE_REQUEST;
+	reg |= (FIELD_PREP(HOST_CFG1_PM_POWER_STATE_REQUEST, state) |
+		HOST_CFG1_PME_EN);
+	regmap_write(google->usb_cfg_regmap,
+		     google->host_cfg_offset + HOST_CFG1_OFFSET, reg);
+
+	ret = regmap_read_poll_timeout(google->usb_cfg_regmap,
+				       google->host_cfg_offset + HC_STATUS_OFFSET, reg,
+				       (FIELD_GET(HC_STATUS_CURRENT_POWER_STATE_U2PMU,
+						  reg) == state &&
+					FIELD_GET(HC_STATUS_CURRENT_POWER_STATE_U3PMU,
+						  reg) == state),
+				       10, 10000);
+
+	if (ret)
+		dev_err(google->dev, "failed to set PMU state %d\n", state);
+
+	return ret;
+}
+
+/*
+ * Clear pme interrupts and report their status.
+ * The hardware requires write-1 then write-0 sequence to clear the interrupt bits.
+ */
+static u32 dwc3_google_clear_pme_irqs(struct dwc3_google *google)
+{
+	u32 irq_status, reg_set, reg_clear;
+
+	regmap_read(google->usb_cfg_regmap,
+		    google->usbint_cfg_offset + USBINT_STATUS_OFFSET, &irq_status);
+
+	irq_status &= (USBINT_STATUS_USBDRD_PME_GEN_U2P_INTR_STS_RAW |
+		       USBINT_STATUS_USBDRD_PME_GEN_U3P_INTR_STS_RAW);
+	if (!irq_status)
+		return irq_status;
+
+	regmap_read(google->usb_cfg_regmap,
+		    google->usbint_cfg_offset + USBINT_CFG1_OFFSET, &reg_set);
+
+	reg_clear = reg_set;
+	if (irq_status & USBINT_STATUS_USBDRD_PME_GEN_U2P_INTR_STS_RAW) {
+		reg_set |= USBINT_CFG1_USBDRD_PME_GEN_U2_INTR_CLR;
+		reg_clear &= ~USBINT_CFG1_USBDRD_PME_GEN_U2_INTR_CLR;
+	}
+	if (irq_status & USBINT_STATUS_USBDRD_PME_GEN_U3P_INTR_STS_RAW) {
+		reg_set |= USBINT_CFG1_USBDRD_PME_GEN_U3_INTR_CLR;
+		reg_clear &= ~USBINT_CFG1_USBDRD_PME_GEN_U3_INTR_CLR;
+	}
+
+	regmap_write(google->usb_cfg_regmap,
+		     google->usbint_cfg_offset + USBINT_CFG1_OFFSET, reg_set);
+	regmap_write(google->usb_cfg_regmap,
+		     google->usbint_cfg_offset + USBINT_CFG1_OFFSET, reg_clear);
+
+	return irq_status;
+}
+
+static void dwc3_google_enable_pme_irq(struct dwc3_google *google)
+{
+	u32 reg;
+
+	regmap_read(google->usb_cfg_regmap,
+		    google->usbint_cfg_offset + USBINT_CFG1_OFFSET, &reg);
+	reg &= ~(USBINT_CFG1_USBDRD_PME_GEN_U2P_INTR_MSK |
+		 USBINT_CFG1_USBDRD_PME_GEN_U3P_INTR_MSK);
+	reg |= (USBINT_CFG1_USBDRD_PME_GEN_U2P_INTR_INT_EN |
+		USBINT_CFG1_USBDRD_PME_GEN_U3P_INTR_INT_EN);
+	regmap_write(google->usb_cfg_regmap,
+		     google->usbint_cfg_offset + USBINT_CFG1_OFFSET, reg);
+
+	enable_irq(google->hs_pme_irq);
+	enable_irq(google->ss_pme_irq);
+	enable_irq_wake(google->hs_pme_irq);
+	enable_irq_wake(google->ss_pme_irq);
+}
+
+static void dwc3_google_disable_pme_irq(struct dwc3_google *google)
+{
+	u32 reg;
+
+	regmap_read(google->usb_cfg_regmap,
+		    google->usbint_cfg_offset + USBINT_CFG1_OFFSET, &reg);
+	reg &= ~(USBINT_CFG1_USBDRD_PME_GEN_U2P_INTR_INT_EN |
+		 USBINT_CFG1_USBDRD_PME_GEN_U3P_INTR_INT_EN);
+	reg |= (USBINT_CFG1_USBDRD_PME_GEN_U2P_INTR_MSK |
+		USBINT_CFG1_USBDRD_PME_GEN_U3P_INTR_MSK);
+	regmap_write(google->usb_cfg_regmap,
+		     google->usbint_cfg_offset + USBINT_CFG1_OFFSET, reg);
+
+	disable_irq_wake(google->hs_pme_irq);
+	disable_irq_wake(google->ss_pme_irq);
+	disable_irq_nosync(google->hs_pme_irq);
+	disable_irq_nosync(google->ss_pme_irq);
+}
+
+static irqreturn_t dwc3_google_resume_irq(int irq, void *data)
+{
+	struct dwc3_google      *google = data;
+	struct dwc3             *dwc = &google->dwc;
+	u32 irq_status, dr_role;
+
+	irq_status = dwc3_google_clear_pme_irqs(google);
+	dr_role = dwc->current_dr_role;
+
+	if (!irq_status || !google->is_hibernation ||
+	    dr_role != DWC3_GCTL_PRTCAP_HOST) {
+		dev_dbg(google->dev, "spurious pme irq %d, hibernation %d, dr_role %u\n",
+			irq, google->is_hibernation, dr_role);
+		return IRQ_HANDLED;
+	}
+
+	if (dwc->xhci)
+		pm_runtime_resume(&dwc->xhci->dev);
+
+	return IRQ_HANDLED;
+}
+
+static int dwc3_google_request_irq(struct dwc3_google *google, struct platform_device *pdev,
+				   const char *irq_name, const char *req_name)
+{
+	int ret;
+	int irq;
+
+	irq = platform_get_irq_byname(pdev, irq_name);
+	if (irq < 0) {
+		dev_err(google->dev, "invalid irq name %s\n", irq_name);
+		return irq;
+	}
+
+	irq_set_status_flags(irq, IRQ_NOAUTOEN);
+	ret = devm_request_threaded_irq(google->dev, irq, NULL,
+					dwc3_google_resume_irq,
+					IRQF_TRIGGER_HIGH | IRQF_ONESHOT,
+					req_name, google);
+	if (ret < 0) {
+		dev_err(google->dev, "failed to request irq %s\n", req_name);
+		return ret;
+	}
+
+	return irq;
+}
+
+static int dwc3_google_usb_psw_pd_notifier(struct notifier_block *nb, unsigned long action, void *d)
+{
+	struct dwc3_google *google = container_of(nb, struct dwc3_google, usb_psw_pd_nb);
+	int ret;
+
+	if (!google->is_hibernation)
+		return NOTIFY_OK;
+
+	if (action == GENPD_NOTIFY_OFF) {
+		dev_dbg(google->dev, "enter D3 power state\n");
+		dwc3_google_set_pmu_state(google, HOST_CFG1_PM_POWER_STATE_D3);
+		ret = reset_control_assert(google->non_sticky_rst);
+		if (ret)
+			dev_err(google->dev, "non sticky reset assert failed: %d\n", ret);
+	} else if (action == GENPD_NOTIFY_ON) {
+		dev_dbg(google->dev, "enter D0 power state\n");
+		dwc3_google_clear_pme_irqs(google);
+		ret = reset_control_deassert(google->non_sticky_rst);
+		if (ret)
+			dev_err(google->dev, "non sticky reset deassert failed: %d\n", ret);
+		dwc3_google_set_pmu_state(google, HOST_CFG1_PM_POWER_STATE_D0);
+	}
+
+	return NOTIFY_OK;
+}
+
+static void dwc3_google_pm_domain_deinit(struct dwc3_google *google)
+{
+	if (google->usb_top_pd_dl)
+		device_link_del(google->usb_top_pd_dl);
+
+	if (!IS_ERR_OR_NULL(google->usb_top_pd)) {
+		device_set_wakeup_capable(google->usb_top_pd, false);
+		dev_pm_domain_detach(google->usb_top_pd, true);
+	}
+
+	if (google->usb_psw_pd_dl)
+		device_link_del(google->usb_psw_pd_dl);
+
+	if (!IS_ERR_OR_NULL(google->usb_psw_pd)) {
+		dev_pm_genpd_remove_notifier(google->usb_psw_pd);
+		dev_pm_domain_detach(google->usb_psw_pd, true);
+	}
+}
+
+static int dwc3_google_pm_domain_init(struct dwc3_google *google)
+{
+	int ret;
+
+	/*
+	 * Establish PM RUNTIME link between dwc dev and its power domain usb_psw_pd,
+	 * register notifier block to handle hibernation.
+	 */
+	google->usb_psw_pd = dev_pm_domain_attach_by_name(google->dev, "psw");
+	if (IS_ERR_OR_NULL(google->usb_psw_pd)) {
+		dev_err(google->dev, "failed to get psw pd");
+		ret = google->usb_psw_pd ? PTR_ERR(google->usb_psw_pd) : -ENODATA;
+		return ret;
+	}
+
+	google->usb_psw_pd_nb.notifier_call = dwc3_google_usb_psw_pd_notifier;
+	ret = dev_pm_genpd_add_notifier(google->usb_psw_pd, &google->usb_psw_pd_nb);
+	if (ret) {
+		dev_err(google->dev, "failed to add psw pd notifier");
+		goto err;
+	}
+
+	google->usb_psw_pd_dl = device_link_add(google->dev, google->usb_psw_pd,
+						DL_FLAG_STATELESS | DL_FLAG_PM_RUNTIME |
+						DL_FLAG_RPM_ACTIVE);
+	if (!google->usb_psw_pd_dl) {
+		dev_err(google->usb_psw_pd, "failed to add device link");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	/*
+	 * usb_top_pd is the parent power domain of usb_psw_pd. Keeping usb_top_pd on
+	 * while usb_psw_pd is off places the controller in a power-gated state,
+	 * essential for hibernation. Acquire a handle to usb_top_pd and sets it as
+	 * wakeup-capable to allow the domain to be left on during system suspend.
+	 */
+	google->usb_top_pd = dev_pm_domain_attach_by_name(google->dev, "top");
+	if (IS_ERR_OR_NULL(google->usb_top_pd)) {
+		dev_err(google->dev, "failed to get top pd");
+		ret = google->usb_top_pd ? PTR_ERR(google->usb_top_pd) : -ENODATA;
+		goto err;
+	}
+	device_set_wakeup_capable(google->usb_top_pd, true);
+
+	google->usb_top_pd_dl = device_link_add(google->dev, google->usb_top_pd,
+						DL_FLAG_STATELESS);
+	if (!google->usb_top_pd_dl) {
+		dev_err(google->usb_top_pd, "failed to add device link");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	return 0;
+
+err:
+	dwc3_google_pm_domain_deinit(google);
+
+	return ret;
+}
+
+static void dwc3_google_program_usb2only(struct dwc3_google *google)
+{
+	u32 reg;
+
+	regmap_read(google->usb_cfg_regmap,
+		    google->usbint_cfg_offset + USBCS_TOP_CTRL_CFG1_OFFSET, &reg);
+	reg |= USBCS_TOP_CTRL_CFG1_USB2ONLY_MODE;
+	regmap_write(google->usb_cfg_regmap,
+		     google->usbint_cfg_offset + USBCS_TOP_CTRL_CFG1_OFFSET, reg);
+}
+
+static int dwc3_google_probe(struct platform_device *pdev)
+{
+	struct dwc3_probe_data	probe_data = {};
+	struct device		*dev = &pdev->dev;
+	struct dwc3_google	*google;
+	struct resource		*res;
+	int			ret;
+	u32			args[2];
+
+	google = devm_kzalloc(&pdev->dev, sizeof(*google), GFP_KERNEL);
+	if (!google)
+		return -ENOMEM;
+
+	google->dev = &pdev->dev;
+
+	ret = dwc3_google_pm_domain_init(google);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "failed to init pdom\n");
+
+	google->usb_cfg_regmap =
+		syscon_regmap_lookup_by_phandle_args(dev->of_node,
+						     "google,usb-cfg-csr",
+						     ARRAY_SIZE(args), args);
+	if (IS_ERR(google->usb_cfg_regmap)) {
+		return dev_err_probe(dev, PTR_ERR(google->usb_cfg_regmap),
+				     "invalid usb cfg csr\n");
+	}
+
+	google->host_cfg_offset = args[0];
+	google->usbint_cfg_offset = args[1];
+
+	if (device_property_match_string(dev, "phy-names", "usb3-phy") < 0) {
+		google->is_usb2only = true;
+		dwc3_google_program_usb2only(google);
+	}
+
+	ret = devm_clk_bulk_get_all_enabled(dev, &google->clks);
+	if (ret < 0) {
+		ret = dev_err_probe(dev, ret, "failed to get and enable clks\n");
+		goto err_deinit_pdom;
+	}
+	google->num_clks = ret;
+
+	ret = dwc3_google_rst_init(google);
+	if (ret) {
+		ret = dev_err_probe(dev, ret, "failed to get resets\n");
+		goto err_deinit_pdom;
+	}
+
+	ret = reset_control_bulk_deassert(google->num_rsts, google->rsts);
+	if (ret) {
+		ret = dev_err_probe(dev, ret, "failed to deassert rsts\n");
+		goto err_deinit_pdom;
+	}
+
+	ret = dwc3_google_request_irq(google, pdev, "hs_pme", "USB HS wakeup");
+	if (ret < 0) {
+		ret = dev_err_probe(dev, ret, "failed to request hs pme irq");
+		goto err_reset_assert;
+	}
+	google->hs_pme_irq = ret;
+
+	ret = dwc3_google_request_irq(google, pdev, "ss_pme", "USB SS wakeup");
+	if (ret < 0) {
+		ret = dev_err_probe(dev, ret, "failed to request ss pme irq");
+		goto err_reset_assert;
+	}
+	google->ss_pme_irq = ret;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = dev_err_probe(dev, -ENODEV, "invalid memory\n");
+		goto err_reset_assert;
+	}
+
+	device_init_wakeup(dev, true);
+
+	google->dwc.dev = dev;
+	probe_data.dwc = &google->dwc;
+	probe_data.res = res;
+	probe_data.ignore_clocks_and_resets = true;
+	ret = dwc3_core_probe(&probe_data);
+	if (ret)  {
+		ret = dev_err_probe(dev, ret, "failed to register DWC3 Core\n");
+		goto err_reset_assert;
+	}
+
+	return 0;
+
+err_reset_assert:
+	reset_control_bulk_assert(google->num_rsts, google->rsts);
+
+err_deinit_pdom:
+	dwc3_google_pm_domain_deinit(google);
+
+	return ret;
+}
+
+static void dwc3_google_remove(struct platform_device *pdev)
+{
+	struct dwc3 *dwc = platform_get_drvdata(pdev);
+	struct dwc3_google *google = to_dwc3_google(dwc);
+
+	dwc3_core_remove(&google->dwc);
+
+	reset_control_bulk_assert(google->num_rsts, google->rsts);
+
+	dwc3_google_pm_domain_deinit(google);
+}
+
+static int dwc3_google_suspend(struct dwc3_google *google, pm_message_t msg)
+{
+	if (pm_runtime_suspended(google->dev))
+		return 0;
+
+	if (google->dwc.current_dr_role == DWC3_GCTL_PRTCAP_HOST) {
+		/*
+		 * Follow dwc3_suspend_common() guidelines for deciding between
+		 * a full teardown and hibernation.
+		 */
+		if (PMSG_IS_AUTO(msg) || device_may_wakeup(google->dev)) {
+			dev_dbg(google->dev, "enter hibernation");
+			pm_runtime_get_sync(google->usb_top_pd);
+			device_wakeup_enable(google->usb_top_pd);
+			dwc3_google_enable_pme_irq(google);
+			google->is_hibernation = true;
+			return 0;
+		}
+	}
+
+	reset_control_bulk_assert(google->num_rsts, google->rsts);
+	clk_bulk_disable_unprepare(google->num_clks, google->clks);
+
+	return 0;
+}
+
+static int dwc3_google_resume(struct dwc3_google *google, pm_message_t msg)
+{
+	int ret;
+
+	if (google->is_hibernation) {
+		dev_dbg(google->dev, "exit hibernation");
+		dwc3_google_disable_pme_irq(google);
+		device_wakeup_disable(google->usb_top_pd);
+		pm_runtime_put_sync(google->usb_top_pd);
+		google->is_hibernation = false;
+		return 0;
+	}
+
+	if (google->is_usb2only)
+		dwc3_google_program_usb2only(google);
+
+	ret = clk_bulk_prepare_enable(google->num_clks, google->clks);
+	if (ret)
+		return ret;
+
+	ret = reset_control_bulk_deassert(google->num_rsts, google->rsts);
+	if (ret) {
+		clk_bulk_disable_unprepare(google->num_clks, google->clks);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int dwc3_google_pm_suspend(struct device *dev)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+	struct dwc3_google *google = to_dwc3_google(dwc);
+	int ret;
+
+	ret = dwc3_pm_suspend(&google->dwc);
+	if (ret)
+		return ret;
+
+	return dwc3_google_suspend(google, PMSG_SUSPEND);
+}
+
+static int dwc3_google_pm_resume(struct device *dev)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+	struct dwc3_google *google = to_dwc3_google(dwc);
+	int ret;
+
+	ret = dwc3_google_resume(google, PMSG_RESUME);
+	if (ret)
+		return ret;
+
+	return dwc3_pm_resume(&google->dwc);
+}
+
+static void dwc3_google_complete(struct device *dev)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+
+	dwc3_pm_complete(dwc);
+}
+
+static int dwc3_google_prepare(struct device *dev)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+
+	return dwc3_pm_prepare(dwc);
+}
+
+static int dwc3_google_runtime_suspend(struct device *dev)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+	struct dwc3_google *google = to_dwc3_google(dwc);
+	int ret;
+
+	ret = dwc3_runtime_suspend(&google->dwc);
+	if (ret)
+		return ret;
+
+	return dwc3_google_suspend(google, PMSG_AUTO_SUSPEND);
+}
+
+static int dwc3_google_runtime_resume(struct device *dev)
+{
+	struct dwc3 *dwc = dev_get_drvdata(dev);
+	struct dwc3_google *google = to_dwc3_google(dwc);
+	int ret;
+
+	ret = dwc3_google_resume(google, PMSG_AUTO_RESUME);
+	if (ret)
+		return ret;
+
+	return dwc3_runtime_resume(&google->dwc);
+}
+
+static int dwc3_google_runtime_idle(struct device *dev)
+{
+	return dwc3_runtime_idle(dev_get_drvdata(dev));
+}
+
+static const struct dev_pm_ops dwc3_google_dev_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(dwc3_google_pm_suspend, dwc3_google_pm_resume)
+	RUNTIME_PM_OPS(dwc3_google_runtime_suspend, dwc3_google_runtime_resume,
+		       dwc3_google_runtime_idle)
+	.complete = pm_sleep_ptr(dwc3_google_complete),
+	.prepare = pm_sleep_ptr(dwc3_google_prepare),
+};
+
+static const struct of_device_id dwc3_google_of_match[] = {
+	{ .compatible = "google,lga-dwc3" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, dwc3_google_of_match);
+
+static struct platform_driver dwc3_google_driver = {
+	.probe		= dwc3_google_probe,
+	.remove		= dwc3_google_remove,
+	.driver		= {
+		.name	= "dwc3-google",
+		.pm	= pm_ptr(&dwc3_google_dev_pm_ops),
+		.of_match_table	= dwc3_google_of_match,
+	},
+};
+
+module_platform_driver(dwc3_google_driver);
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("DesignWare DWC3 Google Glue Driver");

-- 
2.52.0.223.gf5cc29aaa4-goog
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Greg Kroah-Hartman 2 weeks ago
On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> +config USB_DWC3_GOOGLE
> +	tristate "Google Platform"
> +	depends on ARCH_GOOGLE || COMPILE_TEST

There is no ARCH_GOOGLE in the tree now, so how is this supposed to
work?  Shouldn't tools that check for "invalid config options" trigger
on this?

thanks,

greg k-h
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Roy Luo 2 weeks ago
On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> > +config USB_DWC3_GOOGLE
> > +     tristate "Google Platform"
> > +     depends on ARCH_GOOGLE || COMPILE_TEST
>
> There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> work?  Shouldn't tools that check for "invalid config options" trigger
> on this?
>
> thanks,
>
> greg k-h

Hi Greg,

The menuconfig looks like the following and it doesn't complain:
| Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
| Type  : unknown
|
| Symbol: PHY_GOOGLE_USB [=y]
| Type  : tristate
| Defined at drivers/phy/Kconfig:104
|     Prompt: Google Tensor SoC USB PHY driver
|     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]

According to Kconfig documentation [1], the unknown symbol
would simply be evaluated as an "n", which is what we want.
"Convert the symbol into an expression. Boolean and tristate
symbols are simply converted into the respective expression
values. All other symbol types result in ‘n’."

In a different Kconfig documentation, an environment variable
"KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
undefined symbols in the "config input", but I can't find one that
catches undefined symbols in the Kconfig tree itself.

That is, the tool seems to allow this.
However, if this turns out to be a major problem. I think we
can either:
- Remove ARCH_GOOGLE and leave COMPILE_TEST as
  the only dependency. Then add ARCH_GOOGLE back
  later once it's in the tree.
- Defer the whole patch series until ARCH_GOOGLE is
  present (I hope not).

[1] https://docs.kernel.org/kbuild/kconfig-language.html#menu-dependencies
[2] https://www.kernel.org/doc/Documentation/kbuild/kconfig.rst

Regards,
Roy Luo
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Greg Kroah-Hartman 2 days, 2 hours ago
On Thu, Dec 04, 2025 at 11:14:39PM -0800, Roy Luo wrote:
> On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> > > +config USB_DWC3_GOOGLE
> > > +     tristate "Google Platform"
> > > +     depends on ARCH_GOOGLE || COMPILE_TEST
> >
> > There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> > work?  Shouldn't tools that check for "invalid config options" trigger
> > on this?
> >
> > thanks,
> >
> > greg k-h
> 
> Hi Greg,
> 
> The menuconfig looks like the following and it doesn't complain:
> | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
> | Type  : unknown
> |
> | Symbol: PHY_GOOGLE_USB [=y]
> | Type  : tristate
> | Defined at drivers/phy/Kconfig:104
> |     Prompt: Google Tensor SoC USB PHY driver
> |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
> 
> According to Kconfig documentation [1], the unknown symbol
> would simply be evaluated as an "n", which is what we want.
> "Convert the symbol into an expression. Boolean and tristate
> symbols are simply converted into the respective expression
> values. All other symbol types result in ‘n’."
> 
> In a different Kconfig documentation, an environment variable
> "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
> undefined symbols in the "config input", but I can't find one that
> catches undefined symbols in the Kconfig tree itself.
> 
> That is, the tool seems to allow this.
> However, if this turns out to be a major problem. I think we
> can either:
> - Remove ARCH_GOOGLE and leave COMPILE_TEST as
>   the only dependency. Then add ARCH_GOOGLE back
>   later once it's in the tree.

Please do this.  I do not want to take patches that purposfully add
dependencies on config options that might, or might not, appear in the
future.  Please just remove all of the dependancies for now, as they are
not needed, right?

thanks,

greg k-h
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Roy Luo 1 day, 21 hours ago
On Wed, Dec 17, 2025 at 5:24 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Thu, Dec 04, 2025 at 11:14:39PM -0800, Roy Luo wrote:
> > On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> > > > +config USB_DWC3_GOOGLE
> > > > +     tristate "Google Platform"
> > > > +     depends on ARCH_GOOGLE || COMPILE_TEST
> > >
> > > There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> > > work?  Shouldn't tools that check for "invalid config options" trigger
> > > on this?
> > >
> > > thanks,
> > >
> > > greg k-h
> >
> > Hi Greg,
> >
> > The menuconfig looks like the following and it doesn't complain:
> > | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
> > | Type  : unknown
> > |
> > | Symbol: PHY_GOOGLE_USB [=y]
> > | Type  : tristate
> > | Defined at drivers/phy/Kconfig:104
> > |     Prompt: Google Tensor SoC USB PHY driver
> > |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
> >
> > According to Kconfig documentation [1], the unknown symbol
> > would simply be evaluated as an "n", which is what we want.
> > "Convert the symbol into an expression. Boolean and tristate
> > symbols are simply converted into the respective expression
> > values. All other symbol types result in ‘n’."
> >
> > In a different Kconfig documentation, an environment variable
> > "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
> > undefined symbols in the "config input", but I can't find one that
> > catches undefined symbols in the Kconfig tree itself.
> >
> > That is, the tool seems to allow this.
> > However, if this turns out to be a major problem. I think we
> > can either:
> > - Remove ARCH_GOOGLE and leave COMPILE_TEST as
> >   the only dependency. Then add ARCH_GOOGLE back
> >   later once it's in the tree.
>
> Please do this.  I do not want to take patches that purposfully add
> dependencies on config options that might, or might not, appear in the
> future.  Please just remove all of the dependancies for now, as they are
> not needed, right?
>
> thanks,
>
> greg k-h

Greg,

Yes, we can remove ARCH_GOOGLE for now.
To clarify, we're not removing all of the dependencies, we still want
to keep COMPILE_TEST for build tests, right?
Please let me know if you think otherwise.

Thanks,
Roy
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Doug Anderson 1 day, 20 hours ago
Hi,

On Wed, Dec 17, 2025 at 11:18 AM Roy Luo <royluo@google.com> wrote:
>
> On Wed, Dec 17, 2025 at 5:24 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Thu, Dec 04, 2025 at 11:14:39PM -0800, Roy Luo wrote:
> > > On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
> > > <gregkh@linuxfoundation.org> wrote:
> > > >
> > > > On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> > > > > +config USB_DWC3_GOOGLE
> > > > > +     tristate "Google Platform"
> > > > > +     depends on ARCH_GOOGLE || COMPILE_TEST
> > > >
> > > > There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> > > > work?  Shouldn't tools that check for "invalid config options" trigger
> > > > on this?
> > > >
> > > > thanks,
> > > >
> > > > greg k-h
> > >
> > > Hi Greg,
> > >
> > > The menuconfig looks like the following and it doesn't complain:
> > > | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
> > > | Type  : unknown
> > > |
> > > | Symbol: PHY_GOOGLE_USB [=y]
> > > | Type  : tristate
> > > | Defined at drivers/phy/Kconfig:104
> > > |     Prompt: Google Tensor SoC USB PHY driver
> > > |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
> > >
> > > According to Kconfig documentation [1], the unknown symbol
> > > would simply be evaluated as an "n", which is what we want.
> > > "Convert the symbol into an expression. Boolean and tristate
> > > symbols are simply converted into the respective expression
> > > values. All other symbol types result in ‘n’."
> > >
> > > In a different Kconfig documentation, an environment variable
> > > "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
> > > undefined symbols in the "config input", but I can't find one that
> > > catches undefined symbols in the Kconfig tree itself.
> > >
> > > That is, the tool seems to allow this.
> > > However, if this turns out to be a major problem. I think we
> > > can either:
> > > - Remove ARCH_GOOGLE and leave COMPILE_TEST as
> > >   the only dependency. Then add ARCH_GOOGLE back
> > >   later once it's in the tree.
> >
> > Please do this.  I do not want to take patches that purposfully add
> > dependencies on config options that might, or might not, appear in the
> > future.  Please just remove all of the dependancies for now, as they are
> > not needed, right?
> >
> > thanks,
> >
> > greg k-h
>
> Greg,
>
> Yes, we can remove ARCH_GOOGLE for now.
> To clarify, we're not removing all of the dependencies, we still want
> to keep COMPILE_TEST for build tests, right?
> Please let me know if you think otherwise.

I think you'd just remove all of them. Normally COMPILE_TEST just
allows folks to compile stuff even when they don't want the ARCH. We
can can add ARCH_GOOGLE back in later once the config exists.

-Doug
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Roy Luo 1 day, 14 hours ago
On Wed, Dec 17, 2025 at 12:14 PM Doug Anderson <dianders@google.com> wrote:
>
> Hi,
>
> On Wed, Dec 17, 2025 at 11:18 AM Roy Luo <royluo@google.com> wrote:
> >
> > On Wed, Dec 17, 2025 at 5:24 AM Greg Kroah-Hartman
> > <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Thu, Dec 04, 2025 at 11:14:39PM -0800, Roy Luo wrote:
> > > > On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
> > > > <gregkh@linuxfoundation.org> wrote:
> > > > >
> > > > > On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> > > > > > +config USB_DWC3_GOOGLE
> > > > > > +     tristate "Google Platform"
> > > > > > +     depends on ARCH_GOOGLE || COMPILE_TEST
> > > > >
> > > > > There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> > > > > work?  Shouldn't tools that check for "invalid config options" trigger
> > > > > on this?
> > > > >
> > > > > thanks,
> > > > >
> > > > > greg k-h
> > > >
> > > > Hi Greg,
> > > >
> > > > The menuconfig looks like the following and it doesn't complain:
> > > > | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
> > > > | Type  : unknown
> > > > |
> > > > | Symbol: PHY_GOOGLE_USB [=y]
> > > > | Type  : tristate
> > > > | Defined at drivers/phy/Kconfig:104
> > > > |     Prompt: Google Tensor SoC USB PHY driver
> > > > |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
> > > >
> > > > According to Kconfig documentation [1], the unknown symbol
> > > > would simply be evaluated as an "n", which is what we want.
> > > > "Convert the symbol into an expression. Boolean and tristate
> > > > symbols are simply converted into the respective expression
> > > > values. All other symbol types result in ‘n’."
> > > >
> > > > In a different Kconfig documentation, an environment variable
> > > > "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
> > > > undefined symbols in the "config input", but I can't find one that
> > > > catches undefined symbols in the Kconfig tree itself.
> > > >
> > > > That is, the tool seems to allow this.
> > > > However, if this turns out to be a major problem. I think we
> > > > can either:
> > > > - Remove ARCH_GOOGLE and leave COMPILE_TEST as
> > > >   the only dependency. Then add ARCH_GOOGLE back
> > > >   later once it's in the tree.
> > >
> > > Please do this.  I do not want to take patches that purposfully add
> > > dependencies on config options that might, or might not, appear in the
> > > future.  Please just remove all of the dependancies for now, as they are
> > > not needed, right?
> > >
> > > thanks,
> > >
> > > greg k-h
> >
> > Greg,
> >
> > Yes, we can remove ARCH_GOOGLE for now.
> > To clarify, we're not removing all of the dependencies, we still want
> > to keep COMPILE_TEST for build tests, right?
> > Please let me know if you think otherwise.
>
> I think you'd just remove all of them. Normally COMPILE_TEST just
> allows folks to compile stuff even when they don't want the ARCH. We
> can can add ARCH_GOOGLE back in later once the config exists.
>
> -Doug

Doug,

Thanks for chiming in. I'm hesitant to remove COMPILE_TEST
because Greg specifically requested its inclusion in v7 [1].
Also it seems beneficial to get some build coverage before
ARCH_GOOGLE is officially added to the tree.
Greg, could you clarify?

[1] https://lore.kernel.org/linux-usb/2025112144-claw-recolor-49c3@gregkh/

Thanks,
Roy
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Krzysztof Kozlowski 1 day, 9 hours ago
On 18/12/2025 02:34, Roy Luo wrote:
> On Wed, Dec 17, 2025 at 12:14 PM Doug Anderson <dianders@google.com> wrote:
>>
>> Hi,
>>
>> On Wed, Dec 17, 2025 at 11:18 AM Roy Luo <royluo@google.com> wrote:
>>>
>>> On Wed, Dec 17, 2025 at 5:24 AM Greg Kroah-Hartman
>>> <gregkh@linuxfoundation.org> wrote:
>>>>
>>>> On Thu, Dec 04, 2025 at 11:14:39PM -0800, Roy Luo wrote:
>>>>> On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
>>>>> <gregkh@linuxfoundation.org> wrote:
>>>>>>
>>>>>> On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
>>>>>>> +config USB_DWC3_GOOGLE
>>>>>>> +     tristate "Google Platform"
>>>>>>> +     depends on ARCH_GOOGLE || COMPILE_TEST
>>>>>>
>>>>>> There is no ARCH_GOOGLE in the tree now, so how is this supposed to
>>>>>> work?  Shouldn't tools that check for "invalid config options" trigger
>>>>>> on this?
>>>>>>
>>>>>> thanks,
>>>>>>
>>>>>> greg k-h
>>>>>
>>>>> Hi Greg,
>>>>>
>>>>> The menuconfig looks like the following and it doesn't complain:
>>>>> | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
>>>>> | Type  : unknown
>>>>> |
>>>>> | Symbol: PHY_GOOGLE_USB [=y]
>>>>> | Type  : tristate
>>>>> | Defined at drivers/phy/Kconfig:104
>>>>> |     Prompt: Google Tensor SoC USB PHY driver
>>>>> |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
>>>>>
>>>>> According to Kconfig documentation [1], the unknown symbol
>>>>> would simply be evaluated as an "n", which is what we want.
>>>>> "Convert the symbol into an expression. Boolean and tristate
>>>>> symbols are simply converted into the respective expression
>>>>> values. All other symbol types result in ‘n’."
>>>>>
>>>>> In a different Kconfig documentation, an environment variable
>>>>> "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
>>>>> undefined symbols in the "config input", but I can't find one that
>>>>> catches undefined symbols in the Kconfig tree itself.
>>>>>
>>>>> That is, the tool seems to allow this.
>>>>> However, if this turns out to be a major problem. I think we
>>>>> can either:
>>>>> - Remove ARCH_GOOGLE and leave COMPILE_TEST as
>>>>>   the only dependency. Then add ARCH_GOOGLE back
>>>>>   later once it's in the tree.
>>>>
>>>> Please do this.  I do not want to take patches that purposfully add
>>>> dependencies on config options that might, or might not, appear in the
>>>> future.  Please just remove all of the dependancies for now, as they are
>>>> not needed, right?
>>>>
>>>> thanks,
>>>>
>>>> greg k-h
>>>
>>> Greg,
>>>
>>> Yes, we can remove ARCH_GOOGLE for now.
>>> To clarify, we're not removing all of the dependencies, we still want
>>> to keep COMPILE_TEST for build tests, right?
>>> Please let me know if you think otherwise.
>>
>> I think you'd just remove all of them. Normally COMPILE_TEST just
>> allows folks to compile stuff even when they don't want the ARCH. We
>> can can add ARCH_GOOGLE back in later once the config exists.
>>
>> -Doug
> 
> Doug,
> 
> Thanks for chiming in. I'm hesitant to remove COMPILE_TEST
> because Greg specifically requested its inclusion in v7 [1].


What? No, that's not what Greg requested. Your COMPILE_TEST in current
form helps nothing in build testing. It makes absolutely no sense at all.

> Also it seems beneficial to get some build coverage before
> ARCH_GOOGLE is officially added to the tree.

And COMPILE_TEST like you wrote it does not give you that. Please first
read how this function works.

> Greg, could you clarify?

Can you first look at Linux kernel sources to see how this is properly
written?

> 
> [1] https://lore.kernel.org/linux-usb/2025112144-claw-recolor-49c3@gregkh/
> 
> Thanks,
> Roy


Best regards,
Krzysztof
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Roy Luo 21 hours ago
On Wed, Dec 17, 2025 at 11:06 PM Krzysztof Kozlowski <krzk@kernel.org> wrote:
>
> On 18/12/2025 02:34, Roy Luo wrote:
> > On Wed, Dec 17, 2025 at 12:14 PM Doug Anderson <dianders@google.com> wrote:
> >>
> >> Hi,
> >>
> >> On Wed, Dec 17, 2025 at 11:18 AM Roy Luo <royluo@google.com> wrote:
> >>>
> >>> On Wed, Dec 17, 2025 at 5:24 AM Greg Kroah-Hartman
> >>> <gregkh@linuxfoundation.org> wrote:
> >>>>
> >>>> On Thu, Dec 04, 2025 at 11:14:39PM -0800, Roy Luo wrote:
> >>>>> On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
> >>>>> <gregkh@linuxfoundation.org> wrote:
> >>>>>>
> >>>>>> On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> >>>>>>> +config USB_DWC3_GOOGLE
> >>>>>>> +     tristate "Google Platform"
> >>>>>>> +     depends on ARCH_GOOGLE || COMPILE_TEST
> >>>>>>
> >>>>>> There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> >>>>>> work?  Shouldn't tools that check for "invalid config options" trigger
> >>>>>> on this?
> >>>>>>
> >>>>>> thanks,
> >>>>>>
> >>>>>> greg k-h
> >>>>>
> >>>>> Hi Greg,
> >>>>>
> >>>>> The menuconfig looks like the following and it doesn't complain:
> >>>>> | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
> >>>>> | Type  : unknown
> >>>>> |
> >>>>> | Symbol: PHY_GOOGLE_USB [=y]
> >>>>> | Type  : tristate
> >>>>> | Defined at drivers/phy/Kconfig:104
> >>>>> |     Prompt: Google Tensor SoC USB PHY driver
> >>>>> |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
> >>>>>
> >>>>> According to Kconfig documentation [1], the unknown symbol
> >>>>> would simply be evaluated as an "n", which is what we want.
> >>>>> "Convert the symbol into an expression. Boolean and tristate
> >>>>> symbols are simply converted into the respective expression
> >>>>> values. All other symbol types result in ‘n’."
> >>>>>
> >>>>> In a different Kconfig documentation, an environment variable
> >>>>> "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
> >>>>> undefined symbols in the "config input", but I can't find one that
> >>>>> catches undefined symbols in the Kconfig tree itself.
> >>>>>
> >>>>> That is, the tool seems to allow this.
> >>>>> However, if this turns out to be a major problem. I think we
> >>>>> can either:
> >>>>> - Remove ARCH_GOOGLE and leave COMPILE_TEST as
> >>>>>   the only dependency. Then add ARCH_GOOGLE back
> >>>>>   later once it's in the tree.
> >>>>
> >>>> Please do this.  I do not want to take patches that purposfully add
> >>>> dependencies on config options that might, or might not, appear in the
> >>>> future.  Please just remove all of the dependancies for now, as they are
> >>>> not needed, right?
> >>>>
> >>>> thanks,
> >>>>
> >>>> greg k-h
> >>>
> >>> Greg,
> >>>
> >>> Yes, we can remove ARCH_GOOGLE for now.
> >>> To clarify, we're not removing all of the dependencies, we still want
> >>> to keep COMPILE_TEST for build tests, right?
> >>> Please let me know if you think otherwise.
> >>
> >> I think you'd just remove all of them. Normally COMPILE_TEST just
> >> allows folks to compile stuff even when they don't want the ARCH. We
> >> can can add ARCH_GOOGLE back in later once the config exists.
> >>
> >> -Doug
> >
> > Doug,
> >
> > Thanks for chiming in. I'm hesitant to remove COMPILE_TEST
> > because Greg specifically requested its inclusion in v7 [1].
>
>
> What? No, that's not what Greg requested. Your COMPILE_TEST in current
> form helps nothing in build testing. It makes absolutely no sense at all.
>
> > Also it seems beneficial to get some build coverage before
> > ARCH_GOOGLE is officially added to the tree.
>
> And COMPILE_TEST like you wrote it does not give you that. Please first
> read how this function works.
>
> > Greg, could you clarify?
>
> Can you first look at Linux kernel sources to see how this is properly
> written?
>
> >
> > [1] https://lore.kernel.org/linux-usb/2025112144-claw-recolor-49c3@gregkh/
> >
> > Thanks,
> > Roy
>
>
> Best regards,
> Krzysztof

Greg and Krzysztof,

Thanks for the clarification.

Regards,
Roy
Re: [PATCH v9 2/2] usb: dwc3: Add Google Tensor SoC DWC3 glue driver
Posted by Greg Kroah-Hartman 1 day, 9 hours ago
On Wed, Dec 17, 2025 at 05:34:37PM -0800, Roy Luo wrote:
> On Wed, Dec 17, 2025 at 12:14 PM Doug Anderson <dianders@google.com> wrote:
> >
> > Hi,
> >
> > On Wed, Dec 17, 2025 at 11:18 AM Roy Luo <royluo@google.com> wrote:
> > >
> > > On Wed, Dec 17, 2025 at 5:24 AM Greg Kroah-Hartman
> > > <gregkh@linuxfoundation.org> wrote:
> > > >
> > > > On Thu, Dec 04, 2025 at 11:14:39PM -0800, Roy Luo wrote:
> > > > > On Thu, Dec 4, 2025 at 10:05 PM Greg Kroah-Hartman
> > > > > <gregkh@linuxfoundation.org> wrote:
> > > > > >
> > > > > > On Fri, Dec 05, 2025 at 02:26:38AM +0000, Roy Luo wrote:
> > > > > > > +config USB_DWC3_GOOGLE
> > > > > > > +     tristate "Google Platform"
> > > > > > > +     depends on ARCH_GOOGLE || COMPILE_TEST
> > > > > >
> > > > > > There is no ARCH_GOOGLE in the tree now, so how is this supposed to
> > > > > > work?  Shouldn't tools that check for "invalid config options" trigger
> > > > > > on this?
> > > > > >
> > > > > > thanks,
> > > > > >
> > > > > > greg k-h
> > > > >
> > > > > Hi Greg,
> > > > >
> > > > > The menuconfig looks like the following and it doesn't complain:
> > > > > | Symbol: ARCH_GOOGLE [=ARCH_GOOGLE]
> > > > > | Type  : unknown
> > > > > |
> > > > > | Symbol: PHY_GOOGLE_USB [=y]
> > > > > | Type  : tristate
> > > > > | Defined at drivers/phy/Kconfig:104
> > > > > |     Prompt: Google Tensor SoC USB PHY driver
> > > > > |     Depends on: ARCH_GOOGLE || COMPILE_TEST [=y]
> > > > >
> > > > > According to Kconfig documentation [1], the unknown symbol
> > > > > would simply be evaluated as an "n", which is what we want.
> > > > > "Convert the symbol into an expression. Boolean and tristate
> > > > > symbols are simply converted into the respective expression
> > > > > values. All other symbol types result in ‘n’."
> > > > >
> > > > > In a different Kconfig documentation, an environment variable
> > > > > "KCONFIG_WARN_UNKNOWN_SYMBOLS" is there to detect
> > > > > undefined symbols in the "config input", but I can't find one that
> > > > > catches undefined symbols in the Kconfig tree itself.
> > > > >
> > > > > That is, the tool seems to allow this.
> > > > > However, if this turns out to be a major problem. I think we
> > > > > can either:
> > > > > - Remove ARCH_GOOGLE and leave COMPILE_TEST as
> > > > >   the only dependency. Then add ARCH_GOOGLE back
> > > > >   later once it's in the tree.
> > > >
> > > > Please do this.  I do not want to take patches that purposfully add
> > > > dependencies on config options that might, or might not, appear in the
> > > > future.  Please just remove all of the dependancies for now, as they are
> > > > not needed, right?
> > > >
> > > > thanks,
> > > >
> > > > greg k-h
> > >
> > > Greg,
> > >
> > > Yes, we can remove ARCH_GOOGLE for now.
> > > To clarify, we're not removing all of the dependencies, we still want
> > > to keep COMPILE_TEST for build tests, right?
> > > Please let me know if you think otherwise.
> >
> > I think you'd just remove all of them. Normally COMPILE_TEST just
> > allows folks to compile stuff even when they don't want the ARCH. We
> > can can add ARCH_GOOGLE back in later once the config exists.
> >
> > -Doug
> 
> Doug,
> 
> Thanks for chiming in. I'm hesitant to remove COMPILE_TEST
> because Greg specifically requested its inclusion in v7 [1].
> Also it seems beneficial to get some build coverage before
> ARCH_GOOGLE is officially added to the tree.
> Greg, could you clarify?

I wanted it in because it would not build without it on a non "google"
system.  But now, as that option isn't there, just don't have any
dependency, as it's obviously not needed.

thanks,

greg k-h