Re: [RFC] ARM: OMAP2+ i2c NACK without STP

[Tony Lindgren <tony@atomide.com>]

* Jan Weitzel <j.weitzel@phytec.de> [110614 03:01]:
> On OMAP4 OMAP_I2C_STAT_NACK is causing a timeout on the next access.
> The isr cleans all flags in OMAP_I2C_CON_REG by setting OMAP_I2C_CON_STP
> OMAP_I2C_CON_STP is also set in omap_i2c_xfer_msg on the last message.
> 
> According to the TI TSR the sequence for OMAP_I2C_STAT_NACK and
> OMAP_I2C_STAT_AL are nearly the same.
> Removing the OMAP_I2C_CON_STP part in the isr fix the problem.
> Tested on OMAP4430 and OMAP3530 (here NACK was not a problem)
> 
> Signed-off-by: Jan Weitzel <j.weitzel@phytec.de>

Please resend this to Ben Dooks and linux-i2c list Cc'd and also mention
that this fixes booting on 2430sdp that's been failing for a while now.

Acked-by: Tony Lindgren <tony@atomide.com>

> ---
>  drivers/i2c/busses/i2c-omap.c |    6 ++----
>  1 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index 58a58c7..670f2a2 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -836,11 +836,9 @@ complete:
>  				~(OMAP_I2C_STAT_RRDY | OMAP_I2C_STAT_RDR |
>  				OMAP_I2C_STAT_XRDY | OMAP_I2C_STAT_XDR));
>  
> -		if (stat & OMAP_I2C_STAT_NACK) {
> +		if (stat & OMAP_I2C_STAT_NACK)
>  			err |= OMAP_I2C_STAT_NACK;
> -			omap_i2c_write_reg(dev, OMAP_I2C_CON_REG,
> -					   OMAP_I2C_CON_STP);
> -		}
> +
>  		if (stat & OMAP_I2C_STAT_AL) {
>  			dev_err(dev->dev, "Arbitration lost\n");
>  			err |= OMAP_I2C_STAT_AL;
> -- 
> 1.7.0.4
>