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Commit 0646c260 authored by Marek Szyprowski's avatar Marek Szyprowski Committed by Greg Kroah-Hartman
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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: 117053f7 ("i2c: s3c2410: Add polling mode support")
Signed-off-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: default avatarAndi Shyti <andi.shyti@kernel.org>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 47028ccc

drivers/i2c/busses/i2c-s3c2410.c

+10 −17
Original line number Diff line number Diff line
@@ -296,16 +296,6 @@ 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)
@@ -712,7 +702,7 @@ 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;



	if (i2c->suspended)
@@ -735,15 +725,18 @@ 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);

	}



	ret = i2c->msg_idx;