From: Yicong Yang <yangyicong@hisilicon.com>
Date: Mon, 13 Mar 2023 07:45:51 +0000 (+0800)
Subject: i2c: hisi: Avoid redundant interrupts
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a1cfba54130066bc89764ab6adcad8ef952eb12b;p=users%2Fjedix%2Flinux-maple.git

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 d30071f29987..8a61bee745a1 100644
--- 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)