[PATCH v4 4/4] Bluetooth: btintel_pcie: clear the GP0 cause with a W1C write

[Ravindra <ravindra@intel.com>]

MSIX_HW_INT_CAUSES is a write-one-to-clear register. Using a
read-modify-write helper writes zero to GP0, leaving the cause uncleared,
and can acknowledge unrelated pending causes through the read value.

Write only the GP0 bit directly, matching the interrupt handler's W1C
acknowledgment convention.

Fixes: 88c6216a52ea ("Bluetooth: btintel_pcie: Suspend/Resume: Controller doorbell interrupt handling")
Signed-off-by: Ravindra <ravindra@intel.com>
Tested-by: Sergey Lebedev <lsa.uz@pm.me>
Reviewed-by: Sergey Lebedev <lsa.uz@pm.me>
---
 drivers/bluetooth/btintel_pcie.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 553fa927cf0a..9fda057ca9a1 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -4217,10 +4217,12 @@ static int btintel_pcie_set_dxstate(struct btintel_pcie_data *data, u32 dxstate)
 				    "Timeout (%u ms) on alive interrupt for D%d entry, retry count %d",
 				    dx_intr_timeout_ms, dxstate, retry);
 
-			/* clear gp0 cause */
-			btintel_pcie_clr_reg_bits(data,
-						  BTINTEL_PCIE_CSR_MSIX_HW_INT_CAUSES,
-						  BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0);
+			/* MSIX_HW_INT_CAUSES is W1C. Write only GP0 so other
+			 * pending causes are not acknowledged here.
+			 */
+			btintel_pcie_wr_reg32(data,
+					      BTINTEL_PCIE_CSR_MSIX_HW_INT_CAUSES,
+					      BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0);
 		}
 
 		/* gp0_received is set at the top of the handler, before the switch on
-- 
2.43.0