[PATCH v6 0/3] Add USB role switch support to DWC2

[PATCH v6 0/3] Add USB role switch support to DWC2

[Amelie Delaunay]

When using usb-c connector (but it can also be the case with a micro-b
connector), iddig, avalid, bvalid, vbusvalid input signals may not be
connected to the DWC2 OTG controller.
DWC2 OTG controller features an overriding control of the PHY voltage valid
and ID input signals.
So, missing signals can be forced using usb role from usb role switch and
this override feature.

This series adds support for usb role switch to dwc2, by using overriding
control of the PHY voltage valid and ID input signals.

It has been tested on stm32mp157c-dk2 [1], which has a Type-C connector
managed by a Type-C port controller, and connected to USB OTG controller.

[1] https://www.st.com/en/evaluation-tools/stm32mp157c-dk2.html

Amelie Delaunay (3):
  dt-bindings: usb: dwc2: add optional usb-role-switch property
  usb: dwc2: override PHY input signals with usb role switch support
  usb: dwc2: don't use ID/Vbus detection if usb-role-switch on STM32MP15
    SoCs
---
Changes in v6:
- Select USB_ROLE_SWITCH if USB_DWC2, and not only if USB_DWC2_DUAL_ROLE:
  drd.c is built whatever DWC2 mode (DUAL, HOST, PERIPHERAL) as it is used also
  to detect attach/detach (so a-valid/b-valid sessions). 
Changes in v5:
- Use device_property_read_bool instead of of_read_property_bool in params.c
Changes in v4:
- Simplify call to dwc2_force_mode in drd.c
- Add error_drd label in probe error path in platform.c
Changes in v3:
- Fix build issue reported by kernel test robot in drd.c
Changes in v2:
- Previous DT patch already in stm32-next branch so removed from v2 patchset
  "ARM: dts: stm32: enable usb-role-switch on USB OTG on stm32mp15xx-dkx"
- DWC2 DT bindings update added
- Build issue reported by kernel test robot fixed
- Martin's comments taken into account
---
 .../devicetree/bindings/usb/dwc2.yaml         |   4 +
 drivers/usb/dwc2/Kconfig                      |   1 +
 drivers/usb/dwc2/Makefile                     |   2 +-
 drivers/usb/dwc2/core.h                       |   9 +
 drivers/usb/dwc2/drd.c                        | 180 ++++++++++++++++++
 drivers/usb/dwc2/gadget.c                     |   2 +-
 drivers/usb/dwc2/params.c                     |   2 +-
 drivers/usb/dwc2/platform.c                   |  20 +-
 8 files changed, 215 insertions(+), 5 deletions(-)
 create mode 100644 drivers/usb/dwc2/drd.c

-- 
2.17.1

[PATCH v6 1/3] dt-bindings: usb: dwc2: add optional usb-role-switch property

[Amelie Delaunay]

This patch documents the usb-role-switch property in dwc2 bindings, now
that usb-role-switch support is available in dwc2 driver.

Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
---
 Documentation/devicetree/bindings/usb/dwc2.yaml | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/dwc2.yaml b/Documentation/devicetree/bindings/usb/dwc2.yaml
index ffa157a0fce7..fa6612551d08 100644
--- a/Documentation/devicetree/bindings/usb/dwc2.yaml
+++ b/Documentation/devicetree/bindings/usb/dwc2.yaml
@@ -102,6 +102,10 @@ properties:
   dr_mode:
     enum: [host, peripheral, otg]
 
+  usb-role-switch:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description: Support role switch.
+
   g-rx-fifo-size:
     $ref: /schemas/types.yaml#/definitions/uint32
     description: size of rx fifo size in gadget mode.
-- 
2.17.1

[PATCH v6 2/3] usb: dwc2: override PHY input signals with usb role switch support

[Amelie Delaunay]

This patch adds support for usb role switch to dwc2, by using overriding
control of the PHY voltage valid and ID input signals.

iddig signal (ID) can be overridden:
- when setting GUSBCFG_FORCEHOSTMODE, iddig input pin is overridden with 1;
- when setting GUSBCFG_FORCEDEVMODE, iddig input pin is overridden with 0.

avalid/bvalid/vbusvalid signals can be overridden respectively with:
- GOTGCTL_AVALOEN + GOTGCTL_AVALOVAL
- GOTGCTL_BVALOEN + GOTGCTL_BVALOVAL
- GOTGCTL_VBVALEN + GOTGCTL_VBVALOVAL

It is possible to determine valid sessions thanks to usb role switch:
- if USB_ROLE_NONE then !avalid && !bvalid && !vbusvalid
- if USB_ROLE_DEVICE then !avalid && bvalid && vbusvalid
- if USB_ROLE_HOST then avalid && !bvalid && vbusvalid

Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
---
Changes in v5:
- Select USB_ROLE_SWITCH if USB_DWC2, and not only if USB_DWC2_DUAL_ROLE:
  drd.c is built whatever DWC2 mode (DUAL, HOST, PERIPHERAL) as it is used also
  to detect attach/detach (so a-valid/b-valid sessions). 
No changes in v5.
Changes in v4:
- Simplify call to dwc2_force_mode in drd.c
- Add error_drd label in probe error path in platform.c
Changes in v3:
- Fix build issue reported by kernel test robot in drd.c
Changes in v2:
- Fix build issue reported by kernel test robot
- Move call to dwc2_force_mode outside spinlock context
- Add dwc2_drd_exit call in probe error path
---
 drivers/usb/dwc2/Kconfig    |   1 +
 drivers/usb/dwc2/Makefile   |   2 +-
 drivers/usb/dwc2/core.h     |   9 ++
 drivers/usb/dwc2/drd.c      | 180 ++++++++++++++++++++++++++++++++++++
 drivers/usb/dwc2/gadget.c   |   2 +-
 drivers/usb/dwc2/platform.c |  20 +++-
 6 files changed, 210 insertions(+), 4 deletions(-)
 create mode 100644 drivers/usb/dwc2/drd.c

diff --git a/drivers/usb/dwc2/Kconfig b/drivers/usb/dwc2/Kconfig
index 16e1aa304edc..c131719367ec 100644
--- a/drivers/usb/dwc2/Kconfig
+++ b/drivers/usb/dwc2/Kconfig
@@ -5,6 +5,7 @@ config USB_DWC2
 	depends on HAS_DMA
 	depends on USB || USB_GADGET
 	depends on HAS_IOMEM
+	select USB_ROLE_SWITCH
 	help
 	  Say Y here if your system has a Dual Role Hi-Speed USB
 	  controller based on the DesignWare HSOTG IP Core.
diff --git a/drivers/usb/dwc2/Makefile b/drivers/usb/dwc2/Makefile
index 440320cc20a4..2bcd6945df46 100644
--- a/drivers/usb/dwc2/Makefile
+++ b/drivers/usb/dwc2/Makefile
@@ -3,7 +3,7 @@ ccflags-$(CONFIG_USB_DWC2_DEBUG)	+= -DDEBUG
 ccflags-$(CONFIG_USB_DWC2_VERBOSE)	+= -DVERBOSE_DEBUG
 
 obj-$(CONFIG_USB_DWC2)			+= dwc2.o
-dwc2-y					:= core.o core_intr.o platform.o
+dwc2-y					:= core.o core_intr.o platform.o drd.o
 dwc2-y					+= params.o
 
 ifneq ($(filter y,$(CONFIG_USB_DWC2_HOST) $(CONFIG_USB_DWC2_DUAL_ROLE)),)
diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 9deff0400a92..7161344c6522 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -860,6 +860,7 @@ struct dwc2_hregs_backup {
  *                      - USB_DR_MODE_PERIPHERAL
  *                      - USB_DR_MODE_HOST
  *                      - USB_DR_MODE_OTG
+ * @role_sw:		usb_role_switch handle
  * @hcd_enabled:	Host mode sub-driver initialization indicator.
  * @gadget_enabled:	Peripheral mode sub-driver initialization indicator.
  * @ll_hw_enabled:	Status of low-level hardware resources.
@@ -1054,6 +1055,7 @@ struct dwc2_hsotg {
 	struct dwc2_core_params params;
 	enum usb_otg_state op_state;
 	enum usb_dr_mode dr_mode;
+	struct usb_role_switch *role_sw;
 	unsigned int hcd_enabled:1;
 	unsigned int gadget_enabled:1;
 	unsigned int ll_hw_enabled:1;
@@ -1376,6 +1378,11 @@ static inline int dwc2_is_device_mode(struct dwc2_hsotg *hsotg)
 	return (dwc2_readl(hsotg, GINTSTS) & GINTSTS_CURMODE_HOST) == 0;
 }
 
+int dwc2_drd_init(struct dwc2_hsotg *hsotg);
+void dwc2_drd_suspend(struct dwc2_hsotg *hsotg);
+void dwc2_drd_resume(struct dwc2_hsotg *hsotg);
+void dwc2_drd_exit(struct dwc2_hsotg *hsotg);
+
 /*
  * Dump core registers and SPRAM
  */
@@ -1392,6 +1399,7 @@ int dwc2_hsotg_resume(struct dwc2_hsotg *dwc2);
 int dwc2_gadget_init(struct dwc2_hsotg *hsotg);
 void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2,
 				       bool reset);
+void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg);
 void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
 void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
 int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
@@ -1417,6 +1425,7 @@ static inline int dwc2_gadget_init(struct dwc2_hsotg *hsotg)
 { return 0; }
 static inline void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2,
 						     bool reset) {}
+static inline void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg) {}
 static inline void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg) {}
 static inline void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2) {}
 static inline int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg,
diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
new file mode 100644
index 000000000000..2d4176f5788e
--- /dev/null
+++ b/drivers/usb/dwc2/drd.c
@@ -0,0 +1,180 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * drd.c - DesignWare USB2 DRD Controller Dual-role support
+ *
+ * Copyright (C) 2020 STMicroelectronics
+ *
+ * Author(s): Amelie Delaunay <amelie.delaunay@st.com>
+ */
+
+#include <linux/iopoll.h>
+#include <linux/platform_device.h>
+#include <linux/usb/role.h>
+#include "core.h"
+
+static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
+{
+	unsigned long flags;
+	u32 gotgctl;
+
+	spin_lock_irqsave(&hsotg->lock, flags);
+
+	gotgctl = dwc2_readl(hsotg, GOTGCTL);
+	gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN;
+	gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS;
+	gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
+	dwc2_writel(hsotg, gotgctl, GOTGCTL);
+
+	dwc2_force_mode(hsotg, false);
+
+	spin_unlock_irqrestore(&hsotg->lock, flags);
+}
+
+static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
+{
+	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
+
+	/* Check if A-Session is already in the right state */
+	if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
+	    (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
+		return -EALREADY;
+
+	if (valid)
+		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
+	else
+		gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
+	dwc2_writel(hsotg, gotgctl, GOTGCTL);
+
+	return 0;
+}
+
+static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
+{
+	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
+
+	/* Check if B-Session is already in the right state */
+	if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
+	    (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
+		return -EALREADY;
+
+	if (valid)
+		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
+	else
+		gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
+	dwc2_writel(hsotg, gotgctl, GOTGCTL);
+
+	return 0;
+}
+
+static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
+{
+	struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
+	unsigned long flags;
+	int already = 0;
+
+	/* Skip session not in line with dr_mode */
+	if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
+	    (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
+		return -EINVAL;
+
+#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
+	IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
+	/* Skip session if core is in test mode */
+	if (role == USB_ROLE_NONE && hsotg->test_mode) {
+		dev_dbg(hsotg->dev, "Core is in test mode\n");
+		return -EBUSY;
+	}
+#endif
+
+	spin_lock_irqsave(&hsotg->lock, flags);
+
+	if (role == USB_ROLE_HOST) {
+		already = dwc2_ovr_avalid(hsotg, true);
+	} else if (role == USB_ROLE_DEVICE) {
+		already = dwc2_ovr_bvalid(hsotg, true);
+		/* This clear DCTL.SFTDISCON bit */
+		dwc2_hsotg_core_connect(hsotg);
+	} else {
+		if (dwc2_is_device_mode(hsotg)) {
+			if (!dwc2_ovr_bvalid(hsotg, false))
+				/* This set DCTL.SFTDISCON bit */
+				dwc2_hsotg_core_disconnect(hsotg);
+		} else {
+			dwc2_ovr_avalid(hsotg, false);
+		}
+	}
+
+	spin_unlock_irqrestore(&hsotg->lock, flags);
+
+	if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
+		/* This will raise a Connector ID Status Change Interrupt */
+		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
+
+	dev_dbg(hsotg->dev, "%s-session valid\n",
+		role == USB_ROLE_NONE ? "No" :
+		role == USB_ROLE_HOST ? "A" : "B");
+
+	return 0;
+}
+
+int dwc2_drd_init(struct dwc2_hsotg *hsotg)
+{
+	struct usb_role_switch_desc role_sw_desc = {0};
+	struct usb_role_switch *role_sw;
+	int ret;
+
+	if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
+		return 0;
+
+	role_sw_desc.driver_data = hsotg;
+	role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
+	role_sw_desc.set = dwc2_drd_role_sw_set;
+	role_sw_desc.allow_userspace_control = true;
+
+	role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
+	if (IS_ERR(role_sw)) {
+		ret = PTR_ERR(role_sw);
+		dev_err(hsotg->dev,
+			"failed to register role switch: %d\n", ret);
+		return ret;
+	}
+
+	hsotg->role_sw = role_sw;
+
+	/* Enable override and initialize values */
+	dwc2_ovr_init(hsotg);
+
+	return 0;
+}
+
+void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
+{
+	u32 gintsts, gintmsk;
+
+	if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
+		gintmsk = dwc2_readl(hsotg, GINTMSK);
+		gintmsk &= ~GINTSTS_CONIDSTSCHNG;
+		dwc2_writel(hsotg, gintmsk, GINTMSK);
+		gintsts = dwc2_readl(hsotg, GINTSTS);
+		dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
+	}
+}
+
+void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
+{
+	u32 gintsts, gintmsk;
+
+	if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
+		gintsts = dwc2_readl(hsotg, GINTSTS);
+		dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
+		gintmsk = dwc2_readl(hsotg, GINTMSK);
+		gintmsk |= GINTSTS_CONIDSTSCHNG;
+		dwc2_writel(hsotg, gintmsk, GINTMSK);
+	}
+}
+
+void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
+{
+	if (hsotg->role_sw)
+		usb_role_switch_unregister(hsotg->role_sw);
+}
diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 5b9d23991c99..16c5f976f141 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3530,7 +3530,7 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
 		dwc2_readl(hsotg, DOEPCTL0));
 }
 
-static void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
+void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
 {
 	/* set the soft-disconnect bit */
 	dwc2_set_bit(hsotg, DCTL, DCTL_SFTDISCON);
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index b28e90e0b685..238004050557 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -314,6 +314,8 @@ static int dwc2_driver_remove(struct platform_device *dev)
 	if (hsotg->gadget_enabled)
 		dwc2_hsotg_remove(hsotg);
 
+	dwc2_drd_exit(hsotg);
+
 	if (hsotg->params.activate_stm_id_vb_detection)
 		regulator_disable(hsotg->usb33d);
 
@@ -533,10 +535,17 @@ static int dwc2_driver_probe(struct platform_device *dev)
 		dwc2_writel(hsotg, ggpio, GGPIO);
 	}
 
+	retval = dwc2_drd_init(hsotg);
+	if (retval) {
+		if (retval != -EPROBE_DEFER)
+			dev_err(hsotg->dev, "failed to initialize dual-role\n");
+		goto error_init;
+	}
+
 	if (hsotg->dr_mode != USB_DR_MODE_HOST) {
 		retval = dwc2_gadget_init(hsotg);
 		if (retval)
-			goto error_init;
+			goto error_drd;
 		hsotg->gadget_enabled = 1;
 	}
 
@@ -562,7 +571,7 @@ static int dwc2_driver_probe(struct platform_device *dev)
 		if (retval) {
 			if (hsotg->gadget_enabled)
 				dwc2_hsotg_remove(hsotg);
-			goto error_init;
+			goto error_drd;
 		}
 		hsotg->hcd_enabled = 1;
 	}
@@ -594,6 +603,9 @@ static int dwc2_driver_probe(struct platform_device *dev)
 	dwc2_debugfs_exit(hsotg);
 	if (hsotg->hcd_enabled)
 		dwc2_hcd_remove(hsotg);
+error_drd:
+	dwc2_drd_exit(hsotg);
+
 error_init:
 	if (hsotg->params.activate_stm_id_vb_detection)
 		regulator_disable(hsotg->usb33d);
@@ -612,6 +624,8 @@ static int __maybe_unused dwc2_suspend(struct device *dev)
 	if (is_device_mode)
 		dwc2_hsotg_suspend(dwc2);
 
+	dwc2_drd_suspend(dwc2);
+
 	if (dwc2->params.activate_stm_id_vb_detection) {
 		unsigned long flags;
 		u32 ggpio, gotgctl;
@@ -692,6 +706,8 @@ static int __maybe_unused dwc2_resume(struct device *dev)
 	/* Need to restore FORCEDEVMODE/FORCEHOSTMODE */
 	dwc2_force_dr_mode(dwc2);
 
+	dwc2_drd_resume(dwc2);
+
 	if (dwc2_is_device_mode(dwc2))
 		ret = dwc2_hsotg_resume(dwc2);
 
-- 
2.17.1

[PATCH v6 3/3] usb: dwc2: don't use ID/Vbus detection if usb-role-switch on STM32MP15 SoCs

[Amelie Delaunay]

If usb-role-switch is present in the device tree, it means that ID and Vbus
signals are not connected to the OTG controller but to an external
component (GPIOs, Type-C controller). In this configuration, usb role
switch is used to force valid sessions on STM32MP15 SoCs.

Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
---
 drivers/usb/dwc2/params.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
index a3611cdd1dea..50df72f32b4c 100644
--- a/drivers/usb/dwc2/params.c
+++ b/drivers/usb/dwc2/params.c
@@ -185,7 +185,7 @@ static void dwc2_set_stm32mp15_hsotg_params(struct dwc2_hsotg *hsotg)
 	struct dwc2_core_params *p = &hsotg->params;
 
 	p->otg_cap = DWC2_CAP_PARAM_NO_HNP_SRP_CAPABLE;
-	p->activate_stm_id_vb_detection = true;
+	p->activate_stm_id_vb_detection = !device_property_read_bool(hsotg->dev, "usb-role-switch");
 	p->host_rx_fifo_size = 440;
 	p->host_nperio_tx_fifo_size = 256;
 	p->host_perio_tx_fifo_size = 256;
-- 
2.17.1

Re: [PATCH v6 2/3] usb: dwc2: override PHY input signals with usb role switch support

[Amelie DELAUNAY]

Gentle reminder.

Thanks,
Amelie

On 9/9/20 11:35 AM, Amelie DELAUNAY wrote:
> This patch adds support for usb role switch to dwc2, by using overriding
> control of the PHY voltage valid and ID input signals.
> 
> iddig signal (ID) can be overridden:
> - when setting GUSBCFG_FORCEHOSTMODE, iddig input pin is overridden with 1;
> - when setting GUSBCFG_FORCEDEVMODE, iddig input pin is overridden with 0.
> 
> avalid/bvalid/vbusvalid signals can be overridden respectively with:
> - GOTGCTL_AVALOEN + GOTGCTL_AVALOVAL
> - GOTGCTL_BVALOEN + GOTGCTL_BVALOVAL
> - GOTGCTL_VBVALEN + GOTGCTL_VBVALOVAL
> 
> It is possible to determine valid sessions thanks to usb role switch:
> - if USB_ROLE_NONE then !avalid && !bvalid && !vbusvalid
> - if USB_ROLE_DEVICE then !avalid && bvalid && vbusvalid
> - if USB_ROLE_HOST then avalid && !bvalid && vbusvalid
> 
> Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
> ---
> Changes in v5:
> - Select USB_ROLE_SWITCH if USB_DWC2, and not only if USB_DWC2_DUAL_ROLE:
>    drd.c is built whatever DWC2 mode (DUAL, HOST, PERIPHERAL) as it is used also
>    to detect attach/detach (so a-valid/b-valid sessions).
> No changes in v5.
> Changes in v4:
> - Simplify call to dwc2_force_mode in drd.c
> - Add error_drd label in probe error path in platform.c
> Changes in v3:
> - Fix build issue reported by kernel test robot in drd.c
> Changes in v2:
> - Fix build issue reported by kernel test robot
> - Move call to dwc2_force_mode outside spinlock context
> - Add dwc2_drd_exit call in probe error path
> ---
>   drivers/usb/dwc2/Kconfig    |   1 +
>   drivers/usb/dwc2/Makefile   |   2 +-
>   drivers/usb/dwc2/core.h     |   9 ++
>   drivers/usb/dwc2/drd.c      | 180 ++++++++++++++++++++++++++++++++++++
>   drivers/usb/dwc2/gadget.c   |   2 +-
>   drivers/usb/dwc2/platform.c |  20 +++-
>   6 files changed, 210 insertions(+), 4 deletions(-)
>   create mode 100644 drivers/usb/dwc2/drd.c
> 
> diff --git a/drivers/usb/dwc2/Kconfig b/drivers/usb/dwc2/Kconfig
> index 16e1aa304edc..c131719367ec 100644
> --- a/drivers/usb/dwc2/Kconfig
> +++ b/drivers/usb/dwc2/Kconfig
> @@ -5,6 +5,7 @@ config USB_DWC2
>   	depends on HAS_DMA
>   	depends on USB || USB_GADGET
>   	depends on HAS_IOMEM
> +	select USB_ROLE_SWITCH
>   	help
>   	  Say Y here if your system has a Dual Role Hi-Speed USB
>   	  controller based on the DesignWare HSOTG IP Core.
> diff --git a/drivers/usb/dwc2/Makefile b/drivers/usb/dwc2/Makefile
> index 440320cc20a4..2bcd6945df46 100644
> --- a/drivers/usb/dwc2/Makefile
> +++ b/drivers/usb/dwc2/Makefile
> @@ -3,7 +3,7 @@ ccflags-$(CONFIG_USB_DWC2_DEBUG)	+= -DDEBUG
>   ccflags-$(CONFIG_USB_DWC2_VERBOSE)	+= -DVERBOSE_DEBUG
>   
>   obj-$(CONFIG_USB_DWC2)			+= dwc2.o
> -dwc2-y					:= core.o core_intr.o platform.o
> +dwc2-y					:= core.o core_intr.o platform.o drd.o
>   dwc2-y					+= params.o
>   
>   ifneq ($(filter y,$(CONFIG_USB_DWC2_HOST) $(CONFIG_USB_DWC2_DUAL_ROLE)),)
> diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
> index 9deff0400a92..7161344c6522 100644
> --- a/drivers/usb/dwc2/core.h
> +++ b/drivers/usb/dwc2/core.h
> @@ -860,6 +860,7 @@ struct dwc2_hregs_backup {
>    *                      - USB_DR_MODE_PERIPHERAL
>    *                      - USB_DR_MODE_HOST
>    *                      - USB_DR_MODE_OTG
> + * @role_sw:		usb_role_switch handle
>    * @hcd_enabled:	Host mode sub-driver initialization indicator.
>    * @gadget_enabled:	Peripheral mode sub-driver initialization indicator.
>    * @ll_hw_enabled:	Status of low-level hardware resources.
> @@ -1054,6 +1055,7 @@ struct dwc2_hsotg {
>   	struct dwc2_core_params params;
>   	enum usb_otg_state op_state;
>   	enum usb_dr_mode dr_mode;
> +	struct usb_role_switch *role_sw;
>   	unsigned int hcd_enabled:1;
>   	unsigned int gadget_enabled:1;
>   	unsigned int ll_hw_enabled:1;
> @@ -1376,6 +1378,11 @@ static inline int dwc2_is_device_mode(struct dwc2_hsotg *hsotg)
>   	return (dwc2_readl(hsotg, GINTSTS) & GINTSTS_CURMODE_HOST) == 0;
>   }
>   
> +int dwc2_drd_init(struct dwc2_hsotg *hsotg);
> +void dwc2_drd_suspend(struct dwc2_hsotg *hsotg);
> +void dwc2_drd_resume(struct dwc2_hsotg *hsotg);
> +void dwc2_drd_exit(struct dwc2_hsotg *hsotg);
> +
>   /*
>    * Dump core registers and SPRAM
>    */
> @@ -1392,6 +1399,7 @@ int dwc2_hsotg_resume(struct dwc2_hsotg *dwc2);
>   int dwc2_gadget_init(struct dwc2_hsotg *hsotg);
>   void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2,
>   				       bool reset);
> +void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg);
>   void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg);
>   void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2);
>   int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg, int testmode);
> @@ -1417,6 +1425,7 @@ static inline int dwc2_gadget_init(struct dwc2_hsotg *hsotg)
>   { return 0; }
>   static inline void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *dwc2,
>   						     bool reset) {}
> +static inline void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg) {}
>   static inline void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg) {}
>   static inline void dwc2_hsotg_disconnect(struct dwc2_hsotg *dwc2) {}
>   static inline int dwc2_hsotg_set_test_mode(struct dwc2_hsotg *hsotg,
> diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
> new file mode 100644
> index 000000000000..2d4176f5788e
> --- /dev/null
> +++ b/drivers/usb/dwc2/drd.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * drd.c - DesignWare USB2 DRD Controller Dual-role support
> + *
> + * Copyright (C) 2020 STMicroelectronics
> + *
> + * Author(s): Amelie Delaunay <amelie.delaunay@st.com>
> + */
> +
> +#include <linux/iopoll.h>
> +#include <linux/platform_device.h>
> +#include <linux/usb/role.h>
> +#include "core.h"
> +
> +static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
> +{
> +	unsigned long flags;
> +	u32 gotgctl;
> +
> +	spin_lock_irqsave(&hsotg->lock, flags);
> +
> +	gotgctl = dwc2_readl(hsotg, GOTGCTL);
> +	gotgctl |= GOTGCTL_BVALOEN | GOTGCTL_AVALOEN | GOTGCTL_VBVALOEN;
> +	gotgctl |= GOTGCTL_DBNCE_FLTR_BYPASS;
> +	gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
> +	dwc2_writel(hsotg, gotgctl, GOTGCTL);
> +
> +	dwc2_force_mode(hsotg, false);
> +
> +	spin_unlock_irqrestore(&hsotg->lock, flags);
> +}
> +
> +static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
> +{
> +	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
> +
> +	/* Check if A-Session is already in the right state */
> +	if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
> +	    (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
> +		return -EALREADY;
> +
> +	if (valid)
> +		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
> +	else
> +		gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
> +	dwc2_writel(hsotg, gotgctl, GOTGCTL);
> +
> +	return 0;
> +}
> +
> +static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
> +{
> +	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
> +
> +	/* Check if B-Session is already in the right state */
> +	if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
> +	    (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
> +		return -EALREADY;
> +
> +	if (valid)
> +		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
> +	else
> +		gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL);
> +	dwc2_writel(hsotg, gotgctl, GOTGCTL);
> +
> +	return 0;
> +}
> +
> +static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
> +{
> +	struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
> +	unsigned long flags;
> +	int already = 0;
> +
> +	/* Skip session not in line with dr_mode */
> +	if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
> +	    (role == USB_ROLE_HOST && hsotg->dr_mode == USB_DR_MODE_PERIPHERAL))
> +		return -EINVAL;
> +
> +#if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || \
> +	IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)
> +	/* Skip session if core is in test mode */
> +	if (role == USB_ROLE_NONE && hsotg->test_mode) {
> +		dev_dbg(hsotg->dev, "Core is in test mode\n");
> +		return -EBUSY;
> +	}
> +#endif
> +
> +	spin_lock_irqsave(&hsotg->lock, flags);
> +
> +	if (role == USB_ROLE_HOST) {
> +		already = dwc2_ovr_avalid(hsotg, true);
> +	} else if (role == USB_ROLE_DEVICE) {
> +		already = dwc2_ovr_bvalid(hsotg, true);
> +		/* This clear DCTL.SFTDISCON bit */
> +		dwc2_hsotg_core_connect(hsotg);
> +	} else {
> +		if (dwc2_is_device_mode(hsotg)) {
> +			if (!dwc2_ovr_bvalid(hsotg, false))
> +				/* This set DCTL.SFTDISCON bit */
> +				dwc2_hsotg_core_disconnect(hsotg);
> +		} else {
> +			dwc2_ovr_avalid(hsotg, false);
> +		}
> +	}
> +
> +	spin_unlock_irqrestore(&hsotg->lock, flags);
> +
> +	if (!already && hsotg->dr_mode == USB_DR_MODE_OTG)
> +		/* This will raise a Connector ID Status Change Interrupt */
> +		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
> +
> +	dev_dbg(hsotg->dev, "%s-session valid\n",
> +		role == USB_ROLE_NONE ? "No" :
> +		role == USB_ROLE_HOST ? "A" : "B");
> +
> +	return 0;
> +}
> +
> +int dwc2_drd_init(struct dwc2_hsotg *hsotg)
> +{
> +	struct usb_role_switch_desc role_sw_desc = {0};
> +	struct usb_role_switch *role_sw;
> +	int ret;
> +
> +	if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
> +		return 0;
> +
> +	role_sw_desc.driver_data = hsotg;
> +	role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
> +	role_sw_desc.set = dwc2_drd_role_sw_set;
> +	role_sw_desc.allow_userspace_control = true;
> +
> +	role_sw = usb_role_switch_register(hsotg->dev, &role_sw_desc);
> +	if (IS_ERR(role_sw)) {
> +		ret = PTR_ERR(role_sw);
> +		dev_err(hsotg->dev,
> +			"failed to register role switch: %d\n", ret);
> +		return ret;
> +	}
> +
> +	hsotg->role_sw = role_sw;
> +
> +	/* Enable override and initialize values */
> +	dwc2_ovr_init(hsotg);
> +
> +	return 0;
> +}
> +
> +void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
> +{
> +	u32 gintsts, gintmsk;
> +
> +	if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
> +		gintmsk = dwc2_readl(hsotg, GINTMSK);
> +		gintmsk &= ~GINTSTS_CONIDSTSCHNG;
> +		dwc2_writel(hsotg, gintmsk, GINTMSK);
> +		gintsts = dwc2_readl(hsotg, GINTSTS);
> +		dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
> +	}
> +}
> +
> +void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
> +{
> +	u32 gintsts, gintmsk;
> +
> +	if (hsotg->role_sw && !hsotg->params.external_id_pin_ctl) {
> +		gintsts = dwc2_readl(hsotg, GINTSTS);
> +		dwc2_writel(hsotg, gintsts | GINTSTS_CONIDSTSCHNG, GINTSTS);
> +		gintmsk = dwc2_readl(hsotg, GINTMSK);
> +		gintmsk |= GINTSTS_CONIDSTSCHNG;
> +		dwc2_writel(hsotg, gintmsk, GINTMSK);
> +	}
> +}
> +
> +void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
> +{
> +	if (hsotg->role_sw)
> +		usb_role_switch_unregister(hsotg->role_sw);
> +}
> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
> index 5b9d23991c99..16c5f976f141 100644
> --- a/drivers/usb/dwc2/gadget.c
> +++ b/drivers/usb/dwc2/gadget.c
> @@ -3530,7 +3530,7 @@ void dwc2_hsotg_core_init_disconnected(struct dwc2_hsotg *hsotg,
>   		dwc2_readl(hsotg, DOEPCTL0));
>   }
>   
> -static void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
> +void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
>   {
>   	/* set the soft-disconnect bit */
>   	dwc2_set_bit(hsotg, DCTL, DCTL_SFTDISCON);
> diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
> index b28e90e0b685..238004050557 100644
> --- a/drivers/usb/dwc2/platform.c
> +++ b/drivers/usb/dwc2/platform.c
> @@ -314,6 +314,8 @@ static int dwc2_driver_remove(struct platform_device *dev)
>   	if (hsotg->gadget_enabled)
>   		dwc2_hsotg_remove(hsotg);
>   
> +	dwc2_drd_exit(hsotg);
> +
>   	if (hsotg->params.activate_stm_id_vb_detection)
>   		regulator_disable(hsotg->usb33d);
>   
> @@ -533,10 +535,17 @@ static int dwc2_driver_probe(struct platform_device *dev)
>   		dwc2_writel(hsotg, ggpio, GGPIO);
>   	}
>   
> +	retval = dwc2_drd_init(hsotg);
> +	if (retval) {
> +		if (retval != -EPROBE_DEFER)
> +			dev_err(hsotg->dev, "failed to initialize dual-role\n");
> +		goto error_init;
> +	}
> +
>   	if (hsotg->dr_mode != USB_DR_MODE_HOST) {
>   		retval = dwc2_gadget_init(hsotg);
>   		if (retval)
> -			goto error_init;
> +			goto error_drd;
>   		hsotg->gadget_enabled = 1;
>   	}
>   
> @@ -562,7 +571,7 @@ static int dwc2_driver_probe(struct platform_device *dev)
>   		if (retval) {
>   			if (hsotg->gadget_enabled)
>   				dwc2_hsotg_remove(hsotg);
> -			goto error_init;
> +			goto error_drd;
>   		}
>   		hsotg->hcd_enabled = 1;
>   	}
> @@ -594,6 +603,9 @@ static int dwc2_driver_probe(struct platform_device *dev)
>   	dwc2_debugfs_exit(hsotg);
>   	if (hsotg->hcd_enabled)
>   		dwc2_hcd_remove(hsotg);
> +error_drd:
> +	dwc2_drd_exit(hsotg);
> +
>   error_init:
>   	if (hsotg->params.activate_stm_id_vb_detection)
>   		regulator_disable(hsotg->usb33d);
> @@ -612,6 +624,8 @@ static int __maybe_unused dwc2_suspend(struct device *dev)
>   	if (is_device_mode)
>   		dwc2_hsotg_suspend(dwc2);
>   
> +	dwc2_drd_suspend(dwc2);
> +
>   	if (dwc2->params.activate_stm_id_vb_detection) {
>   		unsigned long flags;
>   		u32 ggpio, gotgctl;
> @@ -692,6 +706,8 @@ static int __maybe_unused dwc2_resume(struct device *dev)
>   	/* Need to restore FORCEDEVMODE/FORCEHOSTMODE */
>   	dwc2_force_dr_mode(dwc2);
>   
> +	dwc2_drd_resume(dwc2);
> +
>   	if (dwc2_is_device_mode(dwc2))
>   		ret = dwc2_hsotg_resume(dwc2);
>   
> 

Re: [PATCH v6 0/3] Add USB role switch support to DWC2

[Amelie DELAUNAY]

Gentle reminder on the whole series instead.

Thanks,
Amelie

On 9/9/20 11:35 AM, Amelie DELAUNAY wrote:
> When using usb-c connector (but it can also be the case with a micro-b
> connector), iddig, avalid, bvalid, vbusvalid input signals may not be
> connected to the DWC2 OTG controller.
> DWC2 OTG controller features an overriding control of the PHY voltage valid
> and ID input signals.
> So, missing signals can be forced using usb role from usb role switch and
> this override feature.
> 
> This series adds support for usb role switch to dwc2, by using overriding
> control of the PHY voltage valid and ID input signals.
> 
> It has been tested on stm32mp157c-dk2 [1], which has a Type-C connector
> managed by a Type-C port controller, and connected to USB OTG controller.
> 
> [1] https://www.st.com/en/evaluation-tools/stm32mp157c-dk2.html
> 
> Amelie Delaunay (3):
>    dt-bindings: usb: dwc2: add optional usb-role-switch property
>    usb: dwc2: override PHY input signals with usb role switch support
>    usb: dwc2: don't use ID/Vbus detection if usb-role-switch on STM32MP15
>      SoCs
> ---
> Changes in v6:
> - Select USB_ROLE_SWITCH if USB_DWC2, and not only if USB_DWC2_DUAL_ROLE:
>    drd.c is built whatever DWC2 mode (DUAL, HOST, PERIPHERAL) as it is used also
>    to detect attach/detach (so a-valid/b-valid sessions).
> Changes in v5:
> - Use device_property_read_bool instead of of_read_property_bool in params.c
> Changes in v4:
> - Simplify call to dwc2_force_mode in drd.c
> - Add error_drd label in probe error path in platform.c
> Changes in v3:
> - Fix build issue reported by kernel test robot in drd.c
> Changes in v2:
> - Previous DT patch already in stm32-next branch so removed from v2 patchset
>    "ARM: dts: stm32: enable usb-role-switch on USB OTG on stm32mp15xx-dkx"
> - DWC2 DT bindings update added
> - Build issue reported by kernel test robot fixed
> - Martin's comments taken into account
> ---
>   .../devicetree/bindings/usb/dwc2.yaml         |   4 +
>   drivers/usb/dwc2/Kconfig                      |   1 +
>   drivers/usb/dwc2/Makefile                     |   2 +-
>   drivers/usb/dwc2/core.h                       |   9 +
>   drivers/usb/dwc2/drd.c                        | 180 ++++++++++++++++++
>   drivers/usb/dwc2/gadget.c                     |   2 +-
>   drivers/usb/dwc2/params.c                     |   2 +-
>   drivers/usb/dwc2/platform.c                   |  20 +-
>   8 files changed, 215 insertions(+), 5 deletions(-)
>   create mode 100644 drivers/usb/dwc2/drd.c
> 

Re: [PATCH v6 0/3] Add USB role switch support to DWC2

[Minas Harutyunyan]

On 9/24/2020 4:27 PM, Amelie DELAUNAY wrote:
> Gentle reminder on the whole series instead.
>
> Thanks,
> Amelie
>
> On 9/9/20 11:35 AM, Amelie DELAUNAY wrote:
>> When using usb-c connector (but it can also be the case with a micro-b
>> connector), iddig, avalid, bvalid, vbusvalid input signals may not be
>> connected to the DWC2 OTG controller.
>> DWC2 OTG controller features an overriding control of the PHY voltage 
>> valid
>> and ID input signals.
>> So, missing signals can be forced using usb role from usb role switch 
>> and
>> this override feature.
>>
>> This series adds support for usb role switch to dwc2, by using 
>> overriding
>> control of the PHY voltage valid and ID input signals.
>>
>> It has been tested on stm32mp157c-dk2 [1], which has a Type-C connector
>> managed by a Type-C port controller, and connected to USB OTG 
>> controller.
>>
>> [1] 
>> https://urldefense.com/v3/__https://www.st.com/en/evaluation-tools/stm32mp157c-dk2.html__;!!A4F2R9G_pg!LArZ8m2rAg5r1gjIUgMe3YNtFeRB8li8yKNkU0n3UqbgNZADD96VXRTHT7BLT4o$ 
>>
>> Amelie Delaunay (3):
>>    dt-bindings: usb: dwc2: add optional usb-role-switch property
>>    usb: dwc2: override PHY input signals with usb role switch support
>>    usb: dwc2: don't use ID/Vbus detection if usb-role-switch on 
>> STM32MP15
>>      SoCs
>> ---
>> Changes in v6:
>> - Select USB_ROLE_SWITCH if USB_DWC2, and not only if 
>> USB_DWC2_DUAL_ROLE:
>>    drd.c is built whatever DWC2 mode (DUAL, HOST, PERIPHERAL) as it 
>> is used also
>>    to detect attach/detach (so a-valid/b-valid sessions).
>> Changes in v5:
>> - Use device_property_read_bool instead of of_read_property_bool in 
>> params.c
>> Changes in v4:
>> - Simplify call to dwc2_force_mode in drd.c
>> - Add error_drd label in probe error path in platform.c
>> Changes in v3:
>> - Fix build issue reported by kernel test robot in drd.c
>> Changes in v2:
>> - Previous DT patch already in stm32-next branch so removed from v2 
>> patchset
>>    "ARM: dts: stm32: enable usb-role-switch on USB OTG on 
>> stm32mp15xx-dkx"
>> - DWC2 DT bindings update added
>> - Build issue reported by kernel test robot fixed
>> - Martin's comments taken into account
>> ---
>>   .../devicetree/bindings/usb/dwc2.yaml         |   4 +
>>   drivers/usb/dwc2/Kconfig                      |   1 +
>>   drivers/usb/dwc2/Makefile                     |   2 +-
>>   drivers/usb/dwc2/core.h                       |   9 +
>>   drivers/usb/dwc2/drd.c                        | 180 ++++++++++++++++++
>>   drivers/usb/dwc2/gadget.c                     |   2 +-
>>   drivers/usb/dwc2/params.c                     |   2 +-
>>   drivers/usb/dwc2/platform.c                   |  20 +-
>>   8 files changed, 215 insertions(+), 5 deletions(-)
>>   create mode 100644 drivers/usb/dwc2/drd.c
>>
Acked-by: Minas Harutyunyan <hminas@synopsys.com> for dwc2