3.16.66-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Shubhrajyoti Datta <[email protected]> commit d358def706880defa4c9e87381c5bf086a97d5f9 upstream. 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") Reported-by: Kyle Roeschley <[email protected]> Acked-by: Michal Simek <[email protected]> Signed-off-by: Shubhrajyoti Datta <[email protected]> Tested-by: Kyle Roeschley <[email protected]> Signed-off-by: Wolfram Sang <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- drivers/i2c/busses/i2c-cadence.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/drivers/i2c/busses/i2c-cadence.c +++ b/drivers/i2c/busses/i2c-cadence.c @@ -320,8 +320,10 @@ static void cdns_i2c_mrecv(struct cdns_i * 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; cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); @@ -375,8 +377,11 @@ static void cdns_i2c_msend(struct cdns_i * 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; + cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); /* Clear the interrupts in interrupt status register. */
