4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
[ 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>
---
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;
/*
--
2.43.0
