Thread (35 messages) 35 messages, 3 authors, 2021-03-19

RE: [PATCH 01/11] i2c: imx-lpi2c: directly retrun ISR when detect a NACK

From: Aisheng Dong <aisheng.dong@nxp.com>
Date: 2021-03-19 04:26:28
Also in: linux-i2c, lkml

From: Clark Wang <xiaoning.wang@nxp.com>
Sent: Wednesday, March 17, 2021 2:54 PM

A NACK flag in ISR means i2c bus error. In such codition, there is no need to do
read/write operation. It's better to return ISR directly and then stop i2c
transfer.

Signed-off-by: Gao Pan <redacted>
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>

Regards
Aisheng
quoted hunk ↗ jump to hunk
---
 drivers/i2c/busses/i2c-imx-lpi2c.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c
b/drivers/i2c/busses/i2c-imx-lpi2c.c
index 9db6ccded5e9..bbf44ac95021 100644
--- a/drivers/i2c/busses/i2c-imx-lpi2c.c
+++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
@@ -507,15 +507,17 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
 	lpi2c_imx_intctrl(lpi2c_imx, 0);
 	temp = readl(lpi2c_imx->base + LPI2C_MSR);

+	if (temp & MSR_NDF) {
+		complete(&lpi2c_imx->complete);
+		goto ret;
+	}
+
 	if (temp & MSR_RDF)
 		lpi2c_imx_read_rxfifo(lpi2c_imx);
-
-	if (temp & MSR_TDF)
+	else if (temp & MSR_TDF)
 		lpi2c_imx_write_txfifo(lpi2c_imx);

-	if (temp & MSR_NDF)
-		complete(&lpi2c_imx->complete);
-
+ret:
 	return IRQ_HANDLED;
 }

--
2.25.1
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