[PATCH v6 21/23] phy: rockchip: usbdp: Support going from DP-only mode to USB mode

[Sebastian Reichel]

When a USB-C adapter, which maps all Superspeed lanes to DP is plugged
in, the USB support is disabled in the PHY. When the adapter is
unplugged and a different adapter with USB functionality is plugged in
afterwards, USB functionality is not restored as the USB controller
keeps the PHY enabled for the entire time.

Signed-off-by: Sebastian Reichel <sebastian.reichel at collabora.com>
---
 drivers/phy/rockchip/phy-rockchip-usbdp.c | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
index 81aae3bc5747..7f26b74cb515 100644
--- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
+++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
@@ -178,6 +178,7 @@ struct rk_udphy {
 
 	/* utilized for USB */
 	bool hs; /* flag for high-speed */
+	bool usb_in_use;
 
 	/* utilized for DP */
 	struct gpio_desc *sbu1_dc_gpio;
@@ -1015,6 +1016,10 @@ static int rk_udphy_power_on(struct rk_udphy *udphy, u8 mode)
 		ret = rk_udphy_init(udphy);
 		if (ret)
 			return ret;
+
+		if (udphy->mode & UDPHY_MODE_USB)
+			rk_udphy_u3_port_disable(udphy, false);
+
 		udphy->phy_needs_reinit = false;
 	}
 
@@ -1278,6 +1283,7 @@ static const struct phy_ops rk_udphy_dp_phy_ops = {
 static int rk_udphy_usb3_phy_init(struct phy *phy)
 {
 	struct rk_udphy *udphy = phy_get_drvdata(phy);
+	int ret;
 
 	guard(mutex)(&udphy->mutex);
 
@@ -1287,7 +1293,13 @@ static int rk_udphy_usb3_phy_init(struct phy *phy)
 		return 0;
 	}
 
-	return rk_udphy_power_on(udphy, UDPHY_MODE_USB);
+	ret = rk_udphy_power_on(udphy, UDPHY_MODE_USB);
+	if (ret)
+		return ret;
+
+	udphy->usb_in_use = true;
+
+	return 0;
 }
 
 static int rk_udphy_usb3_phy_exit(struct phy *phy)
@@ -1296,6 +1308,8 @@ static int rk_udphy_usb3_phy_exit(struct phy *phy)
 
 	guard(mutex)(&udphy->mutex);
 
+	udphy->usb_in_use = false;
+
 	/* DP only or high-speed */
 	if (!(udphy->mode & UDPHY_MODE_USB) || udphy->hs)
 		return 0;
@@ -1315,6 +1329,7 @@ static int rk_udphy_typec_mux_set(struct typec_mux_dev *mux,
 				  struct typec_mux_state *state)
 {
 	struct rk_udphy *udphy = typec_mux_get_drvdata(mux);
+	u8 old_mode;
 
 	/*
 	 * Ignore mux events not involving DP AltMode, because
@@ -1326,8 +1341,20 @@ static int rk_udphy_typec_mux_set(struct typec_mux_dev *mux,
 
 	guard(mutex)(&udphy->mutex);
 
+	old_mode = udphy->mode;
+
 	rk_udphy_set_typec_state(udphy, state->mode);
 
+	/*
+	 * If the new mode includes USB but the old one didn't (e.g. leaving
+	 * DP-only), and the USB PHY was already initialized by the USB
+	 * controller, we need to power on the USB side now since no
+	 * subsequent phy_init call will come from the controller.
+	 */
+	if ((udphy->mode & UDPHY_MODE_USB) && !(old_mode & UDPHY_MODE_USB) &&
+	    udphy->usb_in_use && !udphy->hs)
+		return rk_udphy_power_on(udphy, UDPHY_MODE_USB);
+
 	return 0;
 }
 

-- 
2.53.0