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i2c-cpm: Fix to takeback i2c bus master-ship after a collision 

In case of collision on i2c bus the controller which lost bus mastership
stays as a slave for all subsequent transfers. This results in the i2c
controller never writing to the bus for future transactions, resulting
in i2c transfer timeouts.
  This fix checks for a collision on last I2C transaction and sets the
I2COM_MASTER bit for the new transaction.

Signed-off-by: Sachin Surendran <sachin.surendran@alliedtelesis.co.nz>
Signed-off-by: Scott Wood <scottwood@freescale.com>
This commit is contained in:
Sachin Surendran 2012-11-26 11:20:01 +13:00 committed by Scott Wood
parent 98c7355fb3
commit a16d8aa472
1 changed files with 8 additions and 0 deletions
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8
drivers/i2c/busses/i2c-cpm.c
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@ -338,6 +338,14 @@ static int cpm_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
tptr = 0;
rptr = 0;
/*
* If there was a collision in the last i2c transaction,
* Set I2COM_MASTER as it was cleared during collision.
*/
if (in_be16(&tbdf->cbd_sc) & BD_SC_CL) {
out_8(&cpm->i2c_reg->i2com, I2COM_MASTER);
}
while (tptr < num) {
pmsg = &msgs[tptr];
dev_dbg(&adap->dev, "R: %d T: %d\n", rptr, tptr);