i2c: hisi: Avoid redundant interrupts

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>

diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c
index 8c6c7075c765c502e194d222934b294ba966de89..1b7609a34f4a737684aa3198575cd8edaa30605a 100644 (file)
--- a/drivers/i2c/busses/i2c-hisi.c
+++ b/drivers/i2c/busses/i2c-hisi.c
@@ -316,6 +316,13 @@ 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)