phy: renesas: rcar-gen3-usb2: Fix role detection on unbind/bind

It has been observed on the Renesas RZ/G3S SoC that unbinding and binding
the PHY driver leads to role autodetection failures. This issue occurs when
PHY 3 is the first initialized PHY. PHY 3 does not have an interrupt
associated with the USB2_INT_ENABLE register (as
rcar_gen3_int_enable[3] = 0). As a result, rcar_gen3_init_otg() is called
to initialize OTG without enabling PHY interrupts.

To resolve this, add rcar_gen3_is_any_otg_rphy_initialized() and call it in
role_store(), role_show(), and rcar_gen3_init_otg(). At the same time,
rcar_gen3_init_otg() is only called when initialization for a PHY with
interrupt bits is in progress. As a result, the
struct rcar_gen3_phy::otg_initialized is no longer needed.

Fixes: 549b6b5 ("phy: renesas: rcar-gen3-usb2: enable/disable independent irqs")
Cc: stable@vger.kernel.org
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Link: https://lore.kernel.org/r/20250507125032.565017-2-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: claudiubeznea

drivers/phy/renesas/phy-rcar-gen3-usb2.c

@@ -107,7 +107,6 @@ struct rcar_gen3_phy {
 	struct rcar_gen3_chan *ch;
 	u32 int_enable_bits;
 	bool initialized;
-	bool otg_initialized;
 	bool powered;
 };
 
@@ -320,16 +319,15 @@ static bool rcar_gen3_is_any_rphy_initialized(struct rcar_gen3_chan *ch)
 	return false;
 }
 
-static bool rcar_gen3_needs_init_otg(struct rcar_gen3_chan *ch)
+static bool rcar_gen3_is_any_otg_rphy_initialized(struct rcar_gen3_chan *ch)
 {
-	int i;
-
-	for (i = 0; i < NUM_OF_PHYS; i++) {
-		if (ch->rphys[i].otg_initialized)
-			return false;
+	for (enum rcar_gen3_phy_index i = PHY_INDEX_BOTH_HC; i <= PHY_INDEX_EHCI;
+	     i++) {
+		if (ch->rphys[i].initialized)
+			return true;
 	}
 
-	return true;
+	return false;
 }
 
 static bool rcar_gen3_are_all_rphys_power_off(struct rcar_gen3_chan *ch)
@@ -351,7 +349,7 @@ static ssize_t role_store(struct device *dev, struct device_attribute *attr,
 	bool is_b_device;
 	enum phy_mode cur_mode, new_mode;
 
-	if (!ch->is_otg_channel || !rcar_gen3_is_any_rphy_initialized(ch))
+	if (!ch->is_otg_channel || !rcar_gen3_is_any_otg_rphy_initialized(ch))
 		return -EIO;
 
 	if (sysfs_streq(buf, "host"))
@@ -389,7 +387,7 @@ static ssize_t role_show(struct device *dev, struct device_attribute *attr,
 {
 	struct rcar_gen3_chan *ch = dev_get_drvdata(dev);
 
-	if (!ch->is_otg_channel || !rcar_gen3_is_any_rphy_initialized(ch))
+	if (!ch->is_otg_channel || !rcar_gen3_is_any_otg_rphy_initialized(ch))
 		return -EIO;
 
 	return sprintf(buf, "%s\n", rcar_gen3_is_host(ch) ? "host" :
@@ -402,6 +400,9 @@ static void rcar_gen3_init_otg(struct rcar_gen3_chan *ch)
 	void __iomem *usb2_base = ch->base;
 	u32 val;
 
+	if (!ch->is_otg_channel || rcar_gen3_is_any_otg_rphy_initialized(ch))
+		return;
+
 	/* Should not use functions of read-modify-write a register */
 	val = readl(usb2_base + USB2_LINECTRL1);
 	val = (val & ~USB2_LINECTRL1_DP_RPD) | USB2_LINECTRL1_DPRPD_EN |
@@ -465,12 +466,9 @@ static int rcar_gen3_phy_usb2_init(struct phy *p)
 	writel(USB2_SPD_RSM_TIMSET_INIT, usb2_base + USB2_SPD_RSM_TIMSET);
 	writel(USB2_OC_TIMSET_INIT, usb2_base + USB2_OC_TIMSET);
 
-	/* Initialize otg part */
-	if (channel->is_otg_channel) {
-		if (rcar_gen3_needs_init_otg(channel))
-			rcar_gen3_init_otg(channel);
-		rphy->otg_initialized = true;
-	}
+	/* Initialize otg part (only if we initialize a PHY with IRQs). */
+	if (rphy->int_enable_bits)
+		rcar_gen3_init_otg(channel);
 
 	rphy->initialized = true;
 
@@ -486,9 +484,6 @@ static int rcar_gen3_phy_usb2_exit(struct phy *p)
 
 	rphy->initialized = false;
 
-	if (channel->is_otg_channel)
-		rphy->otg_initialized = false;
-
 	val = readl(usb2_base + USB2_INT_ENABLE);
 	val &= ~rphy->int_enable_bits;
 	if (!rcar_gen3_is_any_rphy_initialized(channel))