[PATCH 5.15.y 2/2] serial: 8250_dw: handle reset control deassert error

[Sasha Levin <sashal@kernel.org>]

From: Artem Shimko <a.shimko.dev@gmail.com>

[ Upstream commit daeb4037adf7d3349b4a1fb792f4bc9824686a4b ]

Check the return value of reset_control_deassert() in the probe
function to prevent continuing probe when reset deassertion fails.

Previously, reset_control_deassert() was called without checking its
return value, which could lead to probe continuing even when the
device reset wasn't properly deasserted.

The fix checks the return value and returns an error with dev_err_probe()
if reset deassertion fails, providing better error handling and
diagnostics.

Fixes: acbdad8dd1ab ("serial: 8250_dw: simplify optional reset handling")
Cc: stable <stable@kernel.org>
Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com>
Link: https://patch.msgid.link/20251019095131.252848-1-a.shimko.dev@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/8250/8250_dw.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 6abdebb63ecbe..bcf770f344dac 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -580,7 +580,9 @@ static int dw8250_probe(struct platform_device *pdev)
 	if (IS_ERR(data->rst))
 		return PTR_ERR(data->rst);
 
-	reset_control_deassert(data->rst);
+	err = reset_control_deassert(data->rst);
+	if (err)
+		return dev_err_probe(dev, err, "failed to deassert resets\n");
 
 	err = devm_add_action_or_reset(dev, dw8250_reset_control_assert, data->rst);
 	if (err)
-- 
2.51.0