diff options
| author | Marek Szyprowski <m.szyprowski@samsung.com> | 2023-11-08 19:43:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-26 02:27:52 +0300 |
| commit | 63892860b01987dccdeb38da2c51b145b89953df (patch) | |
| tree | 4804f7a101e75dd2481fad531c094afc0e6c8302 /drivers/i2c | |
| parent | 380540bb06bb1d1b12bdc947d1b8f56cda6b5663 (diff) | |
| download | linux-63892860b01987dccdeb38da2c51b145b89953df.tar.xz | |
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>
Diffstat (limited to 'drivers/i2c')
| -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 36dab9cd208c..2e43b6ccef2a 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; |