[PATCH 5/5] i3c: dw: Resume the controller before unregistering the bus

[Akhil R]

dw_i3c_common_remove() unregisters the I3C bus without resuming the
device first. i3c_master_unregister() ends up in
dw_i3c_master_bus_cleanup(), which writes DEVICE_CTRL, so unbinding the
driver while the controller is runtime suspended accesses registers with
the clocks gated and the reset asserted, which hangs or aborts on most
platforms.

Resume the device around the unregistration and drop the reference
before runtime PM is disabled, so the clocks are running for the
register accesses and the state stays balanced.

Fixes: 62fe9d06f570 ("i3c: dw: Add power management support")
Reported-by: Sashiko AI review <sashiko-bot at kernel.org>
Closes: https://lore.kernel.org/all/20260728071757.5B3CD1F000E9@smtp.kernel.org/
Cc: stable at vger.kernel.org
Assisted-by: Cursor:claude-opus-5
Signed-off-by: Akhil R <akhilrajeev at nvidia.com>
---
 drivers/i3c/master/dw-i3c-master.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 17e1dd4fb5f3..df542ab7744b 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -1723,8 +1723,20 @@ EXPORT_SYMBOL_GPL(dw_i3c_common_probe);
 
 void dw_i3c_common_remove(struct dw_i3c_master *master)
 {
+	int ret;
+
+	/* Unregistering the bus accesses the controller registers */
+	ret = pm_runtime_resume_and_get(master->dev);
+	if (ret < 0)
+		dev_err(master->dev,
+			"<%s> cannot resume i3c bus master, err: %d\n",
+			__func__, ret);
+
 	i3c_master_unregister(&master->base);
 
+	if (ret >= 0)
+		pm_runtime_put_noidle(master->dev);
+
 	/* Balance pm_runtime_get_noresume() from probe() */
 	if (master->quirks & DW_I3C_DISABLE_RUNTIME_PM_QUIRK)
 		pm_runtime_put_noidle(master->dev);
-- 
2.43.0