i2c: hisi: Avoid redundant interrupts

Yicong Yang · wsakernel · commit cc9812a3096d · 2023-03-16T21:00:47.000+01:00
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 &lt;fengsheng5@huawei.com&gt;
Signed-off-by: Yicong Yang &lt;yangyicong@hisilicon.com&gt;
Signed-off-by: Wolfram Sang &lt;wsa@kernel.org&gt;
diff --git 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)

Original file line number	Diff line number	Diff line change
`@@ -316,6 +316,13 @@ static void hisi_i2c_xfer_msg(struct hisi_i2c_controller *ctlr)`
`316`	`316`	`max_write == 0)`
`317`	`317`	`break;`
`318`	`318`	`}`
	`319`	`+`
	`320`	`+ /*`
	`321`	`+ * Disable the TX_EMPTY interrupt after finishing all the messages to`
	`322`	`+ * avoid overwhelming the CPU.`
	`323`	`+ */`
	`324`	`+ if (ctlr->msg_tx_idx == ctlr->msg_num)`
	`325`	`+ hisi_i2c_disable_int(ctlr, HISI_I2C_INT_TX_EMPTY);`
`319`	`326`	`}`
`320`	`327`
`321`	`328`	`static irqreturn_t hisi_i2c_irq(int irq, void *context)`