diff options
| author | Marek Szyprowski <m.szyprowski@samsung.com> | 2023-11-08 17:43:52 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-25 14:52:55 -0800 |
| commit | 38ce342a19ea9cd47d8bcbb3cf677680a8f3ee59 (patch) | |
| tree | 201781c610b5a5a513b1be258427e2f7f65abc8f | |
| parent | 62b3387beef11738eb6ce667601a28fa089fa02c (diff) | |
i2c: s3c24xx: fix read transfers in polling mode
[ Upstream commit 0d9cf23ed55d7ba3ab26d617a3ae507863674c8f ]
To properly handle read transfers in polling mode, no waiting for the ACK
state is needed as it will never come. Just wait a bit to ensure start
state is on the bus and continue processing next bytes.
Fixes: 117053f77a5a ("i2c: s3c2410: Add polling mode support")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Chanho Park <chanho61.park@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>
| -rw-r--r-- | drivers/i2c/busses/i2c-s3c2410.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index b49a1b170bb2..9a6fbb38a5ba 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -220,8 +220,17 @@ static bool is_ack(struct s3c24xx_i2c *i2c) int tries; for (tries = 50; tries; --tries) { - if (readl(i2c->regs + S3C2410_IICCON) - & S3C2410_IICCON_IRQPEND) { + unsigned long tmp = readl(i2c->regs + S3C2410_IICCON); + + if (!(tmp & S3C2410_IICCON_ACKEN)) { + /* + * Wait a bit for the bus to stabilize, + * delay estimated experimentally. + */ + usleep_range(100, 200); + return true; + } + if (tmp & S3C2410_IICCON_IRQPEND) { if (!(readl(i2c->regs + S3C2410_IICSTAT) & S3C2410_IICSTAT_LASTBIT)) return true; |