Hi Carlos,
On Mon, Jul 24, 2023 at 06:55:44PM +0800, carlos.song@xxxxxxx wrote:
> From: Gao Pan <pandy.gao@xxxxxxx>
>
> A NACK flag in ISR means i2c bus error. In such codition,
> there is no need to do read/write operation. It's better
> to return ISR directly and then stop i2c transfer.
>
> Fixes: a55fa9d0e42e ("i2c: imx-lpi2c: add low power i2c bus driver")
> Signed-off-by: Gao Pan <pandy.gao@xxxxxxx>
> Signed-off-by: Carlos Song <carlos.song@xxxxxxx>
> ---
> drivers/i2c/busses/i2c-imx-lpi2c.c | 11 +++++------
> 1 file changed, 5 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c
> index c3287c887c6f..158de0b7f030 100644
> --- a/drivers/i2c/busses/i2c-imx-lpi2c.c
> +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c
> @@ -514,15 +514,14 @@ static irqreturn_t lpi2c_imx_isr(int irq, void *dev_id)
> temp = readl(lpi2c_imx->base + LPI2C_MSR);
> temp &= enabled;
>
> - if (temp & MSR_RDF)
> + if (temp & MSR_NDF) {
> + complete(&lpi2c_imx->complete);
> + return IRQ_HANDLED;
you can actually remove the return here
if (temp & MSR_NDF)
complete();
else if (temp & MSR_RDF)
exfifo();
else if (temp & MSR_TDF)
txfifo();
return IRQ_HANDLED;
BTW, the logic here is changing, as well and it's not described
in the commit log. This patch is not only stopping when a nack is
received (MSR_NDF), but it's also making mutually exclusive
read/write (which I guess are MSR_RDF and MSR_TDF).
Is this what you want? If so, can you please describe it in the
commit log or add a comment describing that the three states are
all mutually exclusive.
Thanks,
Andi
> + } else if (temp & MSR_RDF)
> lpi2c_imx_read_rxfifo(lpi2c_imx);
> -
> - if (temp & MSR_TDF)
> + else if (temp & MSR_TDF)
> lpi2c_imx_write_txfifo(lpi2c_imx);
>
> - if (temp & MSR_NDF)
> - complete(&lpi2c_imx->complete);
> -
> return IRQ_HANDLED;
> }
>
> --
> 2.34.1
>
