From: Yicong Yang <yangyicong@hisilicon.com>

Date: Mon, 13 Mar 2023 15:45:51 +0800

Subject: [PATCH] i2c: hisi: Avoid redundant interrupts

References: bsc#1012628

Patch-mainline: 6.2.12

Git-commit: cc9812a3096d1986caca9a23bee99effc45c08df

[ 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>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 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 f5c37d2f..e067671b 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)

-- 

2.35.3