On Tue, May 09, 2017 at 02:03:51PM +0200, Joakim Tjernlund wrote:
> Current I2C reset procedure is broken in two ways:
> 1) It only generate 1 START instead of 9 STARTs and STOP.
> 2) It leaves the bus Busy so every I2C xfer after the first
> fixup calls the reset routine again, for every xfer there after.
>
> This fixes both errors. Add an iobarrier_rw() when writing the
> I2C control register as well to make sure the register reaches the
> controller in time.
>
> Signed-off-by: Joakim Tjernlund <joakim.tjernlund@xxxxxxxxxxxx>
> ---
>
> Not sure where to sent this as there is no maintainer so adding
> Scott Wood as well.
>
> drivers/i2c/busses/i2c-mpc.c | 24 ++++++++++++++++--------
> 1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-mpc.c b/drivers/i2c/busses/i2c-mpc.c
> index 8393140..09b826d 100644
> --- a/drivers/i2c/busses/i2c-mpc.c
> +++ b/drivers/i2c/busses/i2c-mpc.c
> @@ -86,6 +86,7 @@ struct mpc_i2c_data {
> static inline void writeccr(struct mpc_i2c *i2c, u32 x)
> {
> writeb(x, i2c->base + MPC_I2C_CR);
> + iobarrier_rw();
> }
Why are the barriers in the I/O accessors insufficient?
-Scott
--
To unsubscribe from this list: send the line "unsubscribe linux-i2c" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
