linux-kernel - [PATCH v2 2/7] i2c: npcm: correct the read/write operation procedure

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Message-Id: <20240830034640.7049-3-kfting@nuvoton.com>
Date: Fri, 30 Aug 2024 11:46:35 +0800
From: Tyrone Ting <warp5tw@...il.com>
To: avifishman70@...il.com,
	tmaimon77@...il.com,
	tali.perry1@...il.com,
	venture@...gle.com,
	yuenn@...gle.com,
	benjaminfair@...gle.com,
	andi.shyti@...nel.org,
	andriy.shevchenko@...ux.intel.com,
	wsa@...nel.org,
	rand.sec96@...il.com,
	wsa+renesas@...g-engineering.com,
	warp5tw@...il.com,
	tali.perry@...oton.com,
	Avi.Fishman@...oton.com,
	tomer.maimon@...oton.com,
	KWLIU@...oton.com,
	JJLIU0@...oton.com,
	kfting@...oton.com
Cc: openbmc@...ts.ozlabs.org,
	linux-i2c@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH v2 2/7] i2c: npcm: correct the read/write operation procedure

Originally the driver uses the XMIT bit in SMBnST register to decide
the upcoming i2c transaction. If XMIT bit is 1, then it will be an i2c
write operation. If it's 0, then a read operation will be executed.

After checking the datasheet, the XMIT bit is valid when the i2c module
is acting in a slave role. Use the software status to control the i2c
transaction flow instead when the i2c module is acting in a master role.

Fixes: 48acf8292280 ("i2c: Remove redundant comparison in npcm_i2c_reg_slave")
Signed-off-by: Tyrone Ting <kfting@...oton.com>
---
 drivers/i2c/busses/i2c-npcm7xx.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
index bbcb4d6668ce..2b76dbfba438 100644
--- a/drivers/i2c/busses/i2c-npcm7xx.c
+++ b/drivers/i2c/busses/i2c-npcm7xx.c
@@ -1628,13 +1628,10 @@ static void npcm_i2c_irq_handle_sda(struct npcm_i2c *bus, u8 i2cst)
 			npcm_i2c_wr_byte(bus, bus->dest_addr | BIT(0));
 	/* SDA interrupt, after start\restart */
 	} else {
-		if (NPCM_I2CST_XMIT & i2cst) {
-			bus->operation = I2C_WRITE_OPER;
+		if (bus->operation == I2C_WRITE_OPER)
 			npcm_i2c_irq_master_handler_write(bus);
-		} else {
-			bus->operation = I2C_READ_OPER;
+		else if (bus->operation == I2C_READ_OPER)
 			npcm_i2c_irq_master_handler_read(bus);
-		}
 	}
 }
 
-- 
2.34.1