[PATCH AUTOSEL 6.2 10/25] i2c: hisi: Avoid redundant interrupts

Sasha Levin
2023-04-01T01:42:19Z

From: Yicong Yang <yangyicong@hisilicon.com>

[ 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>
---
drivers/i2c/busses/i2c-hisi.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/drivers/i2c/busses/i2c-hisi.c b/drivers/i2c/busses/i2c-hisi.c
index f5c37d2f536bc..e067671b3ce2e 100644
--- 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)
--
2.39.2