Hi,
> -----Original Message-----
> From: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Sent: Wednesday, October 25, 2023 9:17 PM
> To: linux-samsung-soc@xxxxxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx
> Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>; Krzysztof Kozlowski
> <krzysztof.kozlowski@xxxxxxxxxx>; Alim Akhtar <alim.akhtar@xxxxxxxxxxx>;
> Andi Shyti <andi.shyti@xxxxxxxxxx>; Wolfram Sang <wsa@xxxxxxxxxx>
> Subject: [PATCH v2 1/3] i2c: s3c24xx: fix read transfers in polling mode
>
> 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>
> ---
> 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 127eb3805fac..f9dcb1112a61 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);
Trivial question, but is there any hardware specification related to sleeping for 100-200 microseconds? If any then it would be nice to use const variable instead and add some description about why sleeping here is needed.
Thanks,
Inki Dae
> + return true;
> + }
> + if (tmp & S3C2410_IICCON_IRQPEND) {
> if (!(readl(i2c->regs + S3C2410_IICSTAT)
> & S3C2410_IICSTAT_LASTBIT))
> return true;
> --
> 2.34.1
