[PATCH v2 2/2] i2c: mediatek: Fixup i2c ack error interrupt handling

[Daniel Kurtz]

On Thu, Aug 6, 2015 at 3:22 PM, Eddie Huang <eddie.huang at mediatek.com> wrote:
> When occur i2c ack error, i2c controller generate two interrupts,
> first is the ack error interrupt, then the complete interrupt.
> i2c interrupt handler should keep the two interrupt value, and only
> call complete() for the complete interrupt.
>
> Signed-off-by: Liguo Zhang <liguo.zhang at mediatek.com>
> Signed-off-by: Eddie Huang <eddie.huang at mediatek.com>

Reviewed-by: Daniel Kurtz <djkurtz at chromium.org>

> ---
>  drivers/i2c/busses/i2c-mt65xx.c |   15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-mt65xx.c b/drivers/i2c/busses/i2c-mt65xx.c
> index e28ad4c..c02e6c0 100644
> --- a/drivers/i2c/busses/i2c-mt65xx.c
> +++ b/drivers/i2c/busses/i2c-mt65xx.c
> @@ -557,15 +557,22 @@ static irqreturn_t mtk_i2c_irq(int irqno, void *dev_id)
>  {
>         struct mtk_i2c *i2c = dev_id;
>         u16 restart_flag = 0;
> +       u16 intr_stat;
>
>         if (i2c->dev_comp->auto_restart)
>                 restart_flag = I2C_RS_TRANSFER;
>
> -       i2c->irq_stat = readw(i2c->base + OFFSET_INTR_STAT);
> -       writew(restart_flag | I2C_HS_NACKERR | I2C_ACKERR
> -               | I2C_TRANSAC_COMP, i2c->base + OFFSET_INTR_STAT);
> +       intr_stat = readw(i2c->base + OFFSET_INTR_STAT);
> +       writew(intr_stat, i2c->base + OFFSET_INTR_STAT);
>
> -       complete(&i2c->msg_complete);
> +       /*
> +        * when occurs ack error, i2c controller generate two interrupts
> +        * first is the ack error interrupt, then the complete interrupt
> +        * i2c->irq_stat need keep the two interrupt value.
> +        */
> +       i2c->irq_stat |= intr_stat;
> +       if (i2c->irq_stat & (I2C_TRANSAC_COMP | restart_flag))
> +               complete(&i2c->msg_complete);
>
>         return IRQ_HANDLED;
>  }
> --
> 1.7.9.5
>
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