Hi Marek,
On Tue, Oct 31, 2023 at 03:42:50PM +0100, Marek Szyprowski wrote:
> 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@xxxxxxxxxxx>
> Reviewed-by: Chanho Park <chanho61.park@xxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-s3c2410.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
> index c56886af724e..bcc6afe2ccb5 100644
> --- a/drivers/i2c/busses/i2c-s3c2410.c
> +++ b/drivers/i2c/busses/i2c-s3c2410.c
> @@ -216,8 +216,13 @@ 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)) {
> + usleep_range(100, 200);
> + return true;
even though there are some obscure points here, I trust you have
got here by doing some proper testing and, knowing you, I guess
it was a thorough testing.
I'm going to ack it, however, I think this driver needs some
proper cleanup. I have all the hardware, fortunately, I just need
to find some time to do it.
Reviewed-by: Andi Shyti <andi.shyti@xxxxxxxxxx>
I will appreciate if you also add a comment on how you managed to
get the 100-200 us sleeping range.
Andi
> + }
> + if (tmp & S3C2410_IICCON_IRQPEND) {
> if (!(readl(i2c->regs + S3C2410_IICSTAT)
> & S3C2410_IICSTAT_LASTBIT))
> return true;
> --
> 2.34.1
>
