Patch "i2c: s3c24xx: fix transferring more than one message in polling mode" has been added to the 5.4-stable tree

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This is a note to let you know that I've just added the patch titled

    i2c: s3c24xx: fix transferring more than one message in polling mode

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     i2c-s3c24xx-fix-transferring-more-than-one-message-i.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b86b7502728b1aaa6704d38ac74e70e2dd1d3d89
Author: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Date:   Wed Nov 8 17:43:53 2023 +0100

    i2c: s3c24xx: fix transferring more than one message in polling mode
    
    [ Upstream commit 990489e1042c6c5d6bccf56deca68f8dbeed8180 ]
    
    To properly handle ACK on the bus when transferring more than one
    message in polling mode, move the polling handling loop from
    s3c24xx_i2c_message_start() to s3c24xx_i2c_doxfer(). This way
    i2c_s3c_irq_nextbyte() is always executed till the end, properly
    acknowledging the IRQ bits and no recursive calls to
    i2c_s3c_irq_nextbyte() are made.
    
    While touching this, also fix finishing transfers in polling mode by
    using common code path and always waiting for the bus to become idle
    and disabled.
    
    Fixes: 117053f77a5a ("i2c: s3c2410: Add polling mode support")
    Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
    Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
    Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index a306f8e6702b..7402f71dd24d 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -286,16 +286,6 @@ static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 
 	stat |= S3C2410_IICSTAT_START;
 	writel(stat, i2c->regs + S3C2410_IICSTAT);
-
-	if (i2c->quirks & QUIRK_POLL) {
-		while ((i2c->msg_num != 0) && is_ack(i2c)) {
-			i2c_s3c_irq_nextbyte(i2c, stat);
-			stat = readl(i2c->regs + S3C2410_IICSTAT);
-
-			if (stat & S3C2410_IICSTAT_ARBITR)
-				dev_err(i2c->dev, "deal with arbitration loss\n");
-		}
-	}
 }
 
 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
@@ -703,7 +693,7 @@ static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c)
 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 			      struct i2c_msg *msgs, int num)
 {
-	unsigned long timeout;
+	unsigned long timeout = 0;
 	int ret;
 
 	ret = s3c24xx_i2c_set_master(i2c);
@@ -723,16 +713,19 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 	s3c24xx_i2c_message_start(i2c, msgs);
 
 	if (i2c->quirks & QUIRK_POLL) {
-		ret = i2c->msg_idx;
+		while ((i2c->msg_num != 0) && is_ack(i2c)) {
+			unsigned long stat = readl(i2c->regs + S3C2410_IICSTAT);
 
-		if (ret != num)
-			dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
+			i2c_s3c_irq_nextbyte(i2c, stat);
 
-		goto out;
+			stat = readl(i2c->regs + S3C2410_IICSTAT);
+			if (stat & S3C2410_IICSTAT_ARBITR)
+				dev_err(i2c->dev, "deal with arbitration loss\n");
+		}
+	} else {
+		timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 	}
 
-	timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
-
 	ret = i2c->msg_idx;
 
 	/*




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