[PATCH 6.18.y 1/2] i3c: mipi-i3c-hci: Fix Hot-Join NACK

[Sasha Levin <sashal@kernel.org>]

From: Adrian Hunter <adrian.hunter@intel.com>

[ Upstream commit fa9586bd77ada1e3861c7bef65f6bb9dcf8d9481 ]

The MIPI I3C HCI host controller driver does not implement Hot-Join
handling, yet Hot-Join response control defaults to allowing devices to
Hot-Join the bus.  Configure HC_CONTROL_HOT_JOIN_CTRL to NACK all Hot-Join
attempts.

Fixes: 9ad9a52cce282 ("i3c/master: introduce the mipi-i3c-hci driver")
Cc: stable@vger.kernel.org
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260306072451.11131-3-adrian.hunter@intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Stable-dep-of: c6396b835a5e ("i3c: mipi-i3c-hci: Fix handling of shared IRQs during early initialization")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/i3c/master/mipi-i3c-hci/core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c b/drivers/i3c/master/mipi-i3c-hci/core.c
index 75e6610cfd8129..f2529315445f13 100644
--- a/drivers/i3c/master/mipi-i3c-hci/core.c
+++ b/drivers/i3c/master/mipi-i3c-hci/core.c
@@ -147,7 +147,8 @@ static int i3c_hci_bus_init(struct i3c_master_controller *m)
 	if (hci->quirks & HCI_QUIRK_RESP_BUF_THLD)
 		amd_set_resp_buf_thld(hci);
 
-	reg_set(HC_CONTROL, HC_CONTROL_BUS_ENABLE);
+	/* Enable bus with Hot-Join disabled */
+	reg_set(HC_CONTROL, HC_CONTROL_BUS_ENABLE | HC_CONTROL_HOT_JOIN_CTRL);
 	dev_dbg(&hci->master.dev, "HC_CONTROL = %#x", reg_read(HC_CONTROL));
 
 	return 0;
-- 
2.53.0