[PATCH] i2c-mpc: work around missing-9th-clock-pulse bug

[Grant Likely]

On 7/9/07, Domen Puncer <domen.puncer at telargo.com> wrote:
> Work around a problem reported on:
> http://ozlabs.org/pipermail/linuxppc-embedded/2005-July/019038.html
> Without this patch I2C on mpc5200 becomes unusable after a while.
> Tested on mpc5200 based boards by Matthias and me.
>
> Index: work-powerpc.git/drivers/i2c/busses/i2c-mpc.c
> ===================================================================
> --- work-powerpc.git.orig/drivers/i2c/busses/i2c-mpc.c
> +++ work-powerpc.git/drivers/i2c/busses/i2c-mpc.c
> @@ -153,6 +167,9 @@ static void mpc_i2c_start(struct mpc_i2c
>  static void mpc_i2c_stop(struct mpc_i2c *i2c)
>  {
>         writeccr(i2c, CCR_MEN);
> +       mb();
> +       writeccr(i2c, 0);
> +       mb();
>  }

Are the mb() calls necessary?  The writeccr path includes eieio; is
that not sufficient?

Cheers,
g.

-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
grant.likely at secretlab.ca
(403) 399-0195