Re: i2c: omap: fix NACK and Arbitration Lost irq handling

[Grygorii Strashko <grygorii.strashko-l0cyMroinI0@public.gmane.org>]

On 11/15/2014 03:12 AM, Alexander Kochetkov wrote:
> commit 1d7afc95946487945cc7f5019b41255b72224b70 (i2c: omap: ack IRQ in parts)
> changed the interrupt handler to complete transfers without clearing
> XRDY (AL case) and ARDY (NACK case) flags. XRDY or ARDY interrupt will be
> fired again (in parallel with omap_i2c_xfer_msg). Interrupt handler will
> complete transfers second time. As a result, NACK and AL transfers
> terminates with "transfer timeout" and sometimes client code segfault.
>
> The patch restore original logic of handling NACK and AL interrupts and
> fix race between interrupt handler and omap_i2c_xfer_msg (for AL and
> NACK case only).
>
> Tested on Beagleboard XM C.

Seems you've got the same issue as I :) long time ago
https://lkml.org/lkml/2013/6/7/530

>
> Signed-off-by: Alexander Kochetkov <al.kochet-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> ---
>   drivers/i2c/busses/i2c-omap.c |    2 --
>   1 file changed, 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 90dcc2e..9af7095 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -926,14 +926,12 @@ omap_i2c_isr_thread(int this_irq, void *dev_id)
>   		if (stat & OMAP_I2C_STAT_NACK) {
>   			err |= OMAP_I2C_STAT_NACK;
>   			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_NACK);
> -			break;
>   		}
>
>   		if (stat & OMAP_I2C_STAT_AL) {
>   			dev_err(dev->dev, "Arbitration lost\n");
>   			err |= OMAP_I2C_STAT_AL;
>   			omap_i2c_ack_stat(dev, OMAP_I2C_STAT_AL);
> -			break;
>   		}
>
>   		/*
>