[PATCH v3] phy: k1-usb: add disconnect function support

[Yixun Lan <dlan@kernel.org>]

A disconnect status BIT of USB2 PHY need to be cleared, otherwise
it will fail to work properly during next connection when devices
connect to roothub directly.

Fixes: fe4bc1a08638 ("phy: spacemit: support K1 USB2.0 PHY controller")
Signed-off-by: Yixun Lan <dlan@kernel.org>
---
To: Vinod Koul <vkoul@kernel.org>
To: Neil Armstrong <neil.armstrong@linaro.org>
To: Ze Huang <huang.ze@linux.dev>
Cc: Vladimir Oltean <olteanv@gmail.com>
Cc: Junzhong Pan <panjunzhong@linux.spacemit.com>
Cc: spacemit@lists.linux.dev
Cc: linux-phy@lists.infradead.org
Cc: linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org

Change in v3:
 - split from v2 as bug fix
 - fix alignment to open parenthesis
 - http://lore.kernel.org/r/20260216090112.n5jjpui3luqsybb5@skbuf
 - Link to v2: https://lore.kernel.org/r/20260214-11-k3-usb2-phy-v2-0-6ed31e031ab4@kernel.org
---
 drivers/phy/spacemit/phy-k1-usb2.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/phy/spacemit/phy-k1-usb2.c b/drivers/phy/spacemit/phy-k1-usb2.c
index 342061380012..9215d0b223b2 100644
--- a/drivers/phy/spacemit/phy-k1-usb2.c
+++ b/drivers/phy/spacemit/phy-k1-usb2.c
@@ -48,6 +48,9 @@
 #define  PHY_CLK_HSTXP_EN		BIT(3)		/* clock hstxp enable */
 #define  PHY_HSTXP_MODE			BIT(4)		/* 0: force en_txp to be 1; 1: no force */
 
+#define PHY_K1_HS_HOST_DISC		0x40
+#define  PHY_K1_HS_HOST_DISC_CLR		BIT(0)
+
 #define PHY_PLL_DIV_CFG			0x98
 #define  PHY_FDIV_FRACT_8_15		GENMASK(7, 0)
 #define  PHY_FDIV_FRACT_16_19		GENMASK(11, 8)
@@ -142,9 +145,20 @@ static int spacemit_usb2phy_exit(struct phy *phy)
 	return 0;
 }
 
+static int spacemit_usb2phy_disconnect(struct phy *phy, int port)
+{
+	struct spacemit_usb2phy *sphy = phy_get_drvdata(phy);
+
+	regmap_update_bits(sphy->regmap_base, PHY_K1_HS_HOST_DISC,
+			   PHY_K1_HS_HOST_DISC_CLR, PHY_K1_HS_HOST_DISC_CLR);
+
+	return 0;
+}
+
 static const struct phy_ops spacemit_usb2phy_ops = {
 	.init = spacemit_usb2phy_init,
 	.exit = spacemit_usb2phy_exit,
+	.disconnect = spacemit_usb2phy_disconnect,
 	.owner = THIS_MODULE,
 };
 
-- 
2.52.0