On 2019-02-05 07:45, Shubhrajyoti Datta wrote:
> In case the hold bit is not needed we are carrying the old values.
> Fix the same by resetting the bit when not needed.
>
> Fixes the sporadic i2c bus lockups on National Instruments
> Zynq-based devices.
>
>
> Fixes: df8eb5691c48 ("i2c: Add driver for Cadence I2C controller")
> Acked-by: Michal Simek <michal.simek@xxxxxxxxxx>
> Reported-and-tested-by: Kyle Roeschley <kyle.roeschley@xxxxxx>
> Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
> ---
> v5:
> fix some typos
> v4:
> update fixes tag
> v3:
> Add fixes and Ack
> v2:
> Update commit log
> Also check if the hold_flag
>
> drivers/i2c/busses/i2c-cadence.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
> index 9260574..42c38fd 100644
> --- a/drivers/i2c/busses/i2c-cadence.c
> +++ b/drivers/i2c/busses/i2c-cadence.c
> @@ -628,8 +628,10 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id)
> * Check for the message size against FIFO depth and set the
> * 'hold bus' bit if it is greater than FIFO depth.
> */
> - if (id->recv_count > CDNS_I2C_FIFO_DEPTH)
> + if ((id->recv_count > CDNS_I2C_FIFO_DEPTH) || id->bus_hold_flag)
> ctrl_reg |= CDNS_I2C_CR_HOLD;
> + else
> + ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD;
If you're resending anyway, I'd write this as
ctrl_reg &= ~CDNS_I2C_CR_HOLD;
That's more in line with what the original code looks like.
>
> cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
>
> @@ -686,8 +688,11 @@ static void cdns_i2c_msend(struct cdns_i2c *id)
> * Check for the message size against FIFO depth and set the
> * 'hold bus' bit if it is greater than FIFO depth.
> */
> - if (id->send_count > CDNS_I2C_FIFO_DEPTH)
> + if ((id->send_count > CDNS_I2C_FIFO_DEPTH) || id->bus_hold_flag)
> ctrl_reg |= CDNS_I2C_CR_HOLD;
> + else
> + ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD;
Same here, of course.
Cheers,
Peter
> +
> cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
>
> /* Clear the interrupts in interrupt status register. */
> --
> 2.1.1
>
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