[PATCH v9 35/38] phy: rockchip: usbdp: Simplify power state handling

[Sebastian Reichel <sebastian.reichel@collabora.com>]

Simplify power state handling by introducing sw_mode in addition
to the hw_mode field, so that the PHY knows about the currently
supported modes from the hardware perspective, the current modes
requested by software and the actual hardware status.

Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
---
 drivers/phy/rockchip/phy-rockchip-usbdp.c | 117 +++++++++++++-----------------
 1 file changed, 49 insertions(+), 68 deletions(-)

diff --git a/drivers/phy/rockchip/phy-rockchip-usbdp.c b/drivers/phy/rockchip/phy-rockchip-usbdp.c
index a19b048fb39c..51aac07ef9fe 100644
--- a/drivers/phy/rockchip/phy-rockchip-usbdp.c
+++ b/drivers/phy/rockchip/phy-rockchip-usbdp.c
@@ -176,7 +176,8 @@ struct rk_udphy {
 	bool flip;
 	bool phy_needs_reinit;
 	u8 hw_mode; /* modes currently supported by hardware */
-	u8 status;
+	u8 sw_mode; /* modes currently requested */
+	u8 status; /* current PHY power state */
 
 	/* utilized for USB */
 	bool hs; /* flag for high-speed */
@@ -585,15 +586,6 @@ static void rk_udphy_dp_lane_enable(struct rk_udphy *udphy, int dp_lanes)
 				   CMN_DP_CMN_RSTN, FIELD_PREP(CMN_DP_CMN_RSTN, 0x0));
 }
 
-static void rk_udphy_mode_set(struct rk_udphy *udphy, u8 hw_mode)
-{
-	if (udphy->hw_mode == hw_mode)
-		return;
-
-	udphy->phy_needs_reinit = true;
-	udphy->hw_mode = hw_mode;
-}
-
 static void rk_udphy_set_typec_state(struct rk_udphy *udphy, unsigned long state)
 {
 	u8 hw_mode;
@@ -627,7 +619,7 @@ static void rk_udphy_set_typec_state(struct rk_udphy *udphy, unsigned long state
 		break;
 	}
 
-	rk_udphy_mode_set(udphy, hw_mode);
+	udphy->hw_mode = hw_mode;
 }
 
 static void rk_udphy_set_typec_default_mapping(struct rk_udphy *udphy)
@@ -1023,66 +1015,61 @@ static int rk_udphy_parse_dt(struct rk_udphy *udphy)
 	return rk_udphy_reset_init(udphy, dev);
 }
 
-static int rk_udphy_power_on(struct rk_udphy *udphy, u8 mode)
+static int rk_udphy_update_power_state(struct rk_udphy *udphy)
 {
+	u8 target_mode = udphy->hw_mode & udphy->sw_mode;
 	int ret;
 
-	if (!(udphy->hw_mode & mode)) {
-		dev_info(udphy->dev, "mode 0x%02x is not support\n", mode);
+	if (!udphy->phy_needs_reinit && udphy->status == target_mode)
 		return 0;
-	}
 
-	if (udphy->status == UDPHY_MODE_NONE) {
-		phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_PRE_RESET);
+	/*
+	 * Inform DWC3 driver, that we are about to reset the PHY, so that it can
+	 * assert its PIPE reset lines and avoid DWC3 getting into a buggy state.
+	 */
+	phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_PRE_RESET);
 
-		rk_udphy_u3_port_disable(udphy, true);
-		udelay(10);
+	/*
+	 * Disable USB3 port, which among other things re-routes a DWC3 clock to
+	 * avoid SErrors when the DWC3 registers are accessed while the PHY is
+	 * disabled.
+	 */
+	rk_udphy_u3_port_disable(udphy, true);
+	udelay(10);
 
+	if (udphy->status == UDPHY_MODE_NONE) {
+		/* Power up (incl. clocks) */
 		ret = rk_udphy_setup(udphy);
-		if (ret)
+		if (ret) {
+			phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_POST_RESET);
 			return ret;
-
-		if (!udphy->hs && udphy->hw_mode & UDPHY_MODE_USB)
-			rk_udphy_u3_port_disable(udphy, false);
-		udphy->phy_needs_reinit = false;
-
-		phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_POST_RESET);
-	} else if (udphy->phy_needs_reinit) {
-		phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_PRE_RESET);
-
-		rk_udphy_u3_port_disable(udphy, true);
-		udelay(10);
-
+		}
+	} else if (target_mode == UDPHY_MODE_NONE) {
+		/* Power down (incl. clocks) */
+		rk_udphy_disable(udphy);
+	} else {
+		/* Mode change => re-init */
 		ret = rk_udphy_init(udphy);
 		if (ret) {
 			phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_POST_RESET);
 			return ret;
 		}
-
-		phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_POST_RESET);
-
-		udphy->phy_needs_reinit = false;
 	}
 
-	udphy->status |= mode;
+	/* Ensure USB3 support is enabled when supported and requested */
+	if (!udphy->hs && target_mode & UDPHY_MODE_USB)
+		rk_udphy_u3_port_disable(udphy, false);
 
-	return 0;
-}
-
-static void rk_udphy_power_off(struct rk_udphy *udphy, u8 mode)
-{
-	if (!(udphy->hw_mode & mode)) {
-		dev_info(udphy->dev, "mode 0x%02x is not support\n", mode);
-		return;
-	}
-
-	if (!udphy->status)
-		return;
+	/*
+	 * Inform DWC3, that we are done with the reset, so that it can deassert
+	 * its PIPE reset line.
+	 */
+	phy_notify_reset(udphy->phy_u3, PHY_NOTIFY_POST_RESET);
 
-	udphy->status &= ~mode;
+	udphy->status = target_mode;
+	udphy->phy_needs_reinit = false;
 
-	if (udphy->status == UDPHY_MODE_NONE)
-		rk_udphy_disable(udphy);
+	return 0;
 }
 
 static int rk_udphy_dp_phy_power_on(struct phy *phy)
@@ -1091,9 +1078,11 @@ static int rk_udphy_dp_phy_power_on(struct phy *phy)
 	int ret;
 
 	scoped_guard(mutex, &udphy->mutex) {
+		udphy->sw_mode |= UDPHY_MODE_DP;
+
 		phy_set_bus_width(phy, udphy->dp_lanes);
 
-		ret = rk_udphy_power_on(udphy, UDPHY_MODE_DP);
+		ret = rk_udphy_update_power_state(udphy);
 		if (ret)
 			return ret;
 
@@ -1118,8 +1107,10 @@ static int rk_udphy_dp_phy_power_off(struct phy *phy)
 
 	guard(mutex)(&udphy->mutex);
 
+	udphy->sw_mode &= ~UDPHY_MODE_DP;
+
 	rk_udphy_dp_lane_enable(udphy, 0);
-	rk_udphy_power_off(udphy, UDPHY_MODE_DP);
+	rk_udphy_update_power_state(udphy);
 
 	return 0;
 }
@@ -1329,13 +1320,9 @@ static int rk_udphy_usb3_phy_init(struct phy *phy)
 
 	guard(mutex)(&udphy->mutex);
 
-	/* DP only or high-speed, disable U3 port */
-	if (!(udphy->hw_mode & UDPHY_MODE_USB) || udphy->hs) {
-		rk_udphy_u3_port_disable(udphy, true);
-		return 0;
-	}
+	udphy->sw_mode |= UDPHY_MODE_USB;
 
-	return rk_udphy_power_on(udphy, UDPHY_MODE_USB);
+	return rk_udphy_update_power_state(udphy);
 }
 
 static int rk_udphy_usb3_phy_exit(struct phy *phy)
@@ -1344,15 +1331,9 @@ static int rk_udphy_usb3_phy_exit(struct phy *phy)
 
 	guard(mutex)(&udphy->mutex);
 
-	/* DP only or high-speed */
-	if (!(udphy->hw_mode & UDPHY_MODE_USB) || udphy->hs) {
-		udphy->status &= ~UDPHY_MODE_USB;
-		return 0;
-	}
+	udphy->sw_mode &= ~UDPHY_MODE_USB;
 
-	rk_udphy_power_off(udphy, UDPHY_MODE_USB);
-
-	return 0;
+	return rk_udphy_update_power_state(udphy);
 }
 
 static const struct phy_ops rk_udphy_usb3_phy_ops = {

-- 
2.53.0