4.4-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit d358def706880defa4c9e87381c5bf086a97d5f9 ]
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 kyle.roeschley@ni.com Acked-by: Michal Simek michal.simek@xilinx.com Signed-off-by: Shubhrajyoti Datta shubhrajyoti.datta@xilinx.com Tested-by: Kyle Roeschley kyle.roeschley@ni.com Signed-off-by: Wolfram Sang wsa@the-dreams.de Signed-off-by: Sasha Levin sashal@kernel.org --- 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 84deed6571bd..6d32e6da3110 100644 --- a/drivers/i2c/busses/i2c-cadence.c +++ b/drivers/i2c/busses/i2c-cadence.c @@ -378,8 +378,10 @@ 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;
cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
@@ -436,8 +438,11 @@ 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; + cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET);
/* Clear the interrupts in interrupt status register. */