i2c: hisi: Avoid redundant interrupts

[ Upstream commit cc9812a3096d1986caca9a23bee99effc45c08df ]

After issuing all the messages we can disable the TX_EMPTY interrupts
to avoid handling redundant interrupts. For doing a sinlge bus
detection (i2cdetect -y -r 0) we can reduce ~97% interrupts (before
~12000 after ~400).

Signed-off-by: Sheng Feng <fengsheng5@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c
index d30071f2998793eff405b6041363abd8af35658b..8a61bee745a1691b96891216d13e52b51246c5ed 100644 (file)
--- a/drivers/i2c/busses/i2c-hisi.c
+++ b/drivers/i2c/busses/i2c-hisi.c
@@ -314,6 +314,13 @@ static void hisi_i2c_xfer_msg(struct hisi_i2c_controller *ctlr)
                    max_write == 0)
                        break;
        }
+
+       /*
+        * Disable the TX_EMPTY interrupt after finishing all the messages to
+        * avoid overwhelming the CPU.
+        */
+       if (ctlr->msg_tx_idx == ctlr->msg_num)
+               hisi_i2c_disable_int(ctlr, HISI_I2C_INT_TX_EMPTY);
 }
 
 static irqreturn_t hisi_i2c_irq(int irq, void *context)