When the orientation of a type C cable changes, usbdp set the new
configuration in its internal state but does not write this to the
hardware.

Make use of phy_ops::set_mode to write this new state.  This should be
called by the USB controller when it is notified of a role change
(assuming it is acting as the role switch) and will be called at a point
when the controller does not expect the phy to be operating normally.

Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
---
 drivers/phy/rockchip/phy-rockchip-usbdp.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
index c066cc0a7b4f1..00368fb09307a 100644
--- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
+++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
@@ -1335,9 +1335,23 @@ static int rk_udphy_usb3_phy_exit(struct phy *phy)
 	return 0;
 }
 
+static int rk_udphy_usb3_phy_set_mode(struct phy *phy, enum phy_mode mode, int submode)
+{
+	struct rk_udphy *udphy = phy_get_drvdata(phy);
+	int ret = 0;
+
+	mutex_lock(&udphy->mutex);
+	if (udphy->mode != UDPHY_MODE_NONE)
+		ret = rk_udphy_init(udphy);
+	mutex_unlock(&udphy->mutex);
+
+	return ret;
+}
+
 static const struct phy_ops rk_udphy_usb3_phy_ops = {
 	.init		= rk_udphy_usb3_phy_init,
 	.exit		= rk_udphy_usb3_phy_exit,
+	.set_mode	= rk_udphy_usb3_phy_set_mode,
 	.owner		= THIS_MODULE,
 };
 
-- 
2.50.0

Hi John,

Am Donnerstag, 10. Juli 2025, 17:22:50 Mitteleuropäische Sommerzeit schrieb John Keeping:
> When the orientation of a type C cable changes, usbdp set the new
> configuration in its internal state but does not write this to the
> hardware.
> 
> Make use of phy_ops::set_mode to write this new state.  This should be
> called by the USB controller when it is notified of a role change
> (assuming it is acting as the role switch) and will be called at a point
> when the controller does not expect the phy to be operating normally.
> 
> Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>

with the comments from Ondrej in [0] the whole thing seems to be
slightly more complex


[0] https://patchwork.kernel.org/project/linux-arm-kernel/patch/20250225184519.3586926-3-heiko@sntech.de/

> ---
>  drivers/phy/rockchip/phy-rockchip-usbdp.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> index c066cc0a7b4f1..00368fb09307a 100644
> --- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
> +++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
> @@ -1335,9 +1335,23 @@ static int rk_udphy_usb3_phy_exit(struct phy *phy)
>  	return 0;
>  }
>  
> +static int rk_udphy_usb3_phy_set_mode(struct phy *phy, enum phy_mode mode, int submode)
> +{
> +	struct rk_udphy *udphy = phy_get_drvdata(phy);
> +	int ret = 0;
> +
> +	mutex_lock(&udphy->mutex);
> +	if (udphy->mode != UDPHY_MODE_NONE)
> +		ret = rk_udphy_init(udphy);
> +	mutex_unlock(&udphy->mutex);
> +
> +	return ret;
> +}
> +
>  static const struct phy_ops rk_udphy_usb3_phy_ops = {
>  	.init		= rk_udphy_usb3_phy_init,
>  	.exit		= rk_udphy_usb3_phy_exit,
> +	.set_mode	= rk_udphy_usb3_phy_set_mode,
>  	.owner		= THIS_MODULE,
>  };
>  
> 

On Tue, Jul 15, 2025 at 12:35:47PM +0200, Heiko Stuebner wrote:
> Am Donnerstag, 10. Juli 2025, 17:22:50 Mitteleuropäische Sommerzeit schrieb John Keeping:
> > When the orientation of a type C cable changes, usbdp set the new
> > configuration in its internal state but does not write this to the
> > hardware.
> > 
> > Make use of phy_ops::set_mode to write this new state.  This should be
> > called by the USB controller when it is notified of a role change
> > (assuming it is acting as the role switch) and will be called at a point
> > when the controller does not expect the phy to be operating normally.
> > 
> > Signed-off-by: John Keeping <jkeeping@inmusicbrands.com>
> 
> with the comments from Ondrej in [0] the whole thing seems to be
> slightly more complex
> 
> 
> [0] https://patchwork.kernel.org/project/linux-arm-kernel/patch/20250225184519.3586926-3-heiko@sntech.de/

I spent some more time looking at this and have found what looks like
the vendor kernel's approach to this issue [1].  It seems that Rockchip
set the autosuspend time to 100ms and hope that is sufficiently short to
allow the controller to suspend whenever a cable is unplugged.

[1] https://github.com/rockchip-linux/kernel/commit/5ac62b80f7471ee9858ab0459af07180de938b51

Having experimented some more, I was able to do something similar
without needing any changes to the phy driver by applying the changes
below on top of patch 1/2 in this thread.  This depends on runtime PM to
ensure the controller is suspended whenever a cable is unplugged, but if
CONFIG_PM is enabled then it should address those concerns because the
controller will be shutdown and the phy configured via phy_init() in the
normal sequence.

It sounds like Thinh doesn't like this approach, but if the requirement
is for the controller to be shutdown and restarted whenever the
orientation changes I don't think we can avoid some changes in dwc3.

--- >8 ---
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 6573cca0eeaf5..b707afd38cc27 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -199,6 +199,10 @@ static void __dwc3_set_mode(struct work_struct *work)
 		dwc3_otg_update(dwc, 1);
 		break;
 	default:
+		if (dwc->force_suspended) {
+			pm_runtime_force_resume(dwc->dev);
+			dwc->force_suspended = 0;
+		}
 		break;
 	}
 
@@ -272,6 +276,9 @@ static void __dwc3_set_mode(struct work_struct *work)
 		dwc3_otg_update(dwc, 0);
 		break;
 	default:
+		ret = pm_runtime_force_suspend(dwc->dev);
+		if (!ret)
+			dwc->force_suspended = 1;
 		break;
 	}
 
@@ -2485,7 +2492,7 @@ static int dwc3_suspend_common(struct dwc3 *dwc, pm_message_t msg)
 		dwc3_core_exit(dwc);
 		break;
 	default:
-		/* do nothing */
+		dwc3_core_exit(dwc);
 		break;
 	}
 
@@ -2552,7 +2559,9 @@ static int dwc3_resume_common(struct dwc3 *dwc, pm_message_t msg)
 
 		break;
 	default:
-		/* do nothing */
+		ret = dwc3_core_init_for_resume(dwc);
+		if (ret)
+			return ret;
 		break;
 	}
 
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index d5b985fa12f4d..7e1d480c59ae1 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1390,6 +1390,7 @@ struct dwc3 {
 	unsigned		sys_wakeup:1;
 	unsigned		wakeup_configured:1;
 	unsigned		suspended:1;
+	unsigned		force_suspended:1;
 	unsigned		susphy_state:1;
 
 	u16			imod_interval;
diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index 8f427afa8eb93..16aac8384ca3d 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -461,6 +461,7 @@ static int dwc3_usb_role_switch_set(struct usb_role_switch *sw,
 		break;
 	}
 
+	flush_work(&dwc->drd_work);
 	dwc3_set_mode(dwc, mode);
 	return 0;
 }