Stop the OTG state machines running blind in either role

Widens the #160 fix, which was scoped too narrowly to host role, and fixes
flare-edge#168.

Device role was deliberately left alone on the reasoning that the state
machine is only meaningless when the port is a host. That was wrong. On a
board with no extcon phandle the machine has no external role signal in
EITHER direction, and with bvalid pinned high by the VBUS bypass its charger
detection cannot be meaningful at all. In device role its verdict suspends
the phy underneath a bound gadget, so the USB recovery link dies.

Reproduced deterministically on warden-c8a3 with a host attached:

  device role, host attached   ccf=1  phy_sus=0x0    udc=configured  works
  -> host role                 ccf=1  phy_sus=0x0    udc=(none)
  -> back to gadget            ccf=0  phy_sus=0x1d1  udc=configured  SUSPENDED
  -> +15s / +30s               ccf=0  phy_sus=0x1d1  udc=configured  never recovers

and the 2207:0019 device disappears from the host for good.

Nothing notices, because every obvious signal lies: udc state reads
"configured", usb0 carrier reads 1, and DCTL RUN_STOP reads 1, so the gadget
really is asserting its pullup. It asserts into a phy whose analog front end
and 480M clock are off, so the SoC sees SE0 and the host sees no device at
all, not even an enumeration error.

It cannot self-heal either. bvalid is pinned high, so a host attaching later
produces no VBUS edge for the machine to trigger on: it ran once, powered the
phy off, and nothing re-evaluates. That is why a reboot appears to fix it and
why this read as a cable fault for weeks. It is not, and the cables were fine.

Gated on the extcon being self-allocated rather than on the board compatible,
so it describes the actual precondition: no external role signal exists.

Renamed from 29-usb2phy-no-otg-sm-in-host.patch, whose name now misstated the
scope.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MVGTC78dgCGfRANNKjoPea

patches/29-usb2phy-no-blind-otg-sm.patch

@@ -17,7 +17,39 @@ diff --git a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c b/drivers/phy/rockchi
  };
  
  /**
-@@ -649,11 +651,52 @@
+@@ -239,6 +241,8 @@
+  * @dcd_retries: The retry count used to track Data contact
+  *		 detection process.
+  * @edev: extcon device for notification registration
++ * @edev_self_allocated: no extcon phandle in DT, so the OTG state machine
++ *			has no external role signal at all
+  * @irq: muxed interrupt for single irq configuration
+  * @phy_cfg: phy register configuration, assigned by driver data.
+  * @ports: phy port instance.
+@@ -257,6 +261,7 @@
+ 	enum power_supply_type	chg_type;
+ 	u8			dcd_retries;
+ 	struct extcon_dev	*edev;
++	bool			edev_self_allocated;
+ 	int			irq;
+ 	const struct rockchip_usb2phy_cfg	*phy_cfg;
+ 	struct rockchip_usb2phy_port	ports[USB2PHY_NUM_PORTS];
+@@ -459,6 +464,14 @@
+ 		if (ret)
+ 			return dev_err_probe(rphy->dev, ret,
+ 					     "failed to register extcon device\n");
++
++		/*
++		 * Nothing external drives the role on this board. The extcon
++		 * below is ours, and no code ever sets a cable state on it, so
++		 * the OTG state machine's view of the world is permanently
++		 * blank rather than merely stale.
++		 */
++		rphy->edev_self_allocated = true;
+ 	}
+ 
+ 	rphy->edev = edev;
+@@ -649,11 +662,52 @@
  	return 0;
  }
  
@@ -70,23 +102,33 @@ diff --git a/drivers/phy/rockchip/phy-rockchip-inno-usb2.c b/drivers/phy/rockchi
  	.owner		= THIS_MODULE,
  };
  
-@@ -667,6 +710,10 @@
+@@ -667,6 +721,15 @@
  	unsigned long delay;
  	bool vbus_attach, sch_work, notify_charger;
  
-+	/* In host role this machine can only get the answer wrong. */
++	/*
-+	if (rport->host_mode)
++	 * This machine can only get the answer wrong here. In host role its
++	 * verdict suspends a phy that is enumerating a device (#160); with a
++	 * self-allocated extcon it has no role signal in EITHER direction, and
++	 * in device role it strands the gadget the same way (#168).
++	 */
++	if (rport->host_mode || rphy->edev_self_allocated)
 +		return;
 +
  	vbus_attach = property_enabled(rphy->grf,
  				       &rport->port_cfg->utmi_bvalid);
  
-@@ -825,6 +872,10 @@
+@@ -825,6 +888,15 @@
  	bool is_dcd, tmout, vout, vbus_attach;
  	unsigned long delay;
  
-+	/* Never probe the front end of a port that is hosting a device. */
++	/*
-+	if (rport->host_mode)
++	 * Never probe the front end of a port that is hosting a device, and
++	 * never at all on a board whose bvalid is pinned high by the VBUS
++	 * bypass: charger detection cannot be meaningful there, and its DCP
++	 * verdict powers the phy off underneath a working link (#160, #168).
++	 */
++	if (rport->host_mode || rphy->edev_self_allocated)
 +		return;
 +
  	vbus_attach = property_enabled(rphy->grf, &rport->port_cfg->utmi_bvalid);

patches/README.md

@@ -19,7 +19,7 @@ with `../build/warden_defconfig` -> `zImage` + `rv1106-warden.dtb`).
 | `20-arch-dts-bindings.patch` | `arch/arm` DTs (`rv1106.dtsi`, `rv1106-warden.dts`, pinctrl), mach, configs, `include/dt-bindings` |
 | `25-usb-phy.patch` | inno-usb2 phy |
 | `27-usb-phy-tuning.patch` | inno-usb2 phy: RV1106 signal-quality register tuning |
-| `29-usb2phy-no-otg-sm-in-host.patch` | inno-usb2 phy: keep the OTG/charger state machines out of host role |
+| `29-usb2phy-no-blind-otg-sm.patch` | inno-usb2 phy: stop the OTG/charger state machines running blind |
 | `30-drm-vop-panel-rgb.patch` | VOP (`rgb_dclk_pol`=0 + WIN1 scanout), panel-simple bus-format, rockchip_rgb |
 | `35-mailbox-hpmcu.patch` | rockchip-mailbox (rv1106 num_chans=1) |
 | `40-pvtm-soc.patch` | PVTM (core+pmu) + `include/soc/rockchip/pvtm.h` |