4.19-stable review patch. If anyone has any objections, please let me know.
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From: Marek Szyprowski m.szyprowski@samsung.com
[ 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@samsung.com Reviewed-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-s3c2410.c | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 deletions(-)
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 8186af573a02..fe245dfdaf4d 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -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) @@ -735,16 +725,19 @@ 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;
/*