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i2c: cadence: Fix the hold bit setting
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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: df8eb56 ("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>
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Shubhrajyoti Datta authored and Wolfram Sang committed Feb 15, 2019
1 parent d139371 commit d358def
Showing 1 changed file with 7 additions and 2 deletions.
9 changes: 7 additions & 2 deletions drivers/i2c/busses/i2c-cadence.c
Original file line number Diff line number Diff line change
Expand Up @@ -382,8 +382,10 @@ 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);

Expand Down Expand Up @@ -440,8 +442,11 @@ 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. */
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