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authorSachin Surendran <sachin.surendran@alliedtelesis.co.nz>2012-11-26 11:20:01 +1300
committerScott Wood <scottwood@freescale.com>2013-06-25 16:53:26 -0500
commita16d8aa4726a944ffc1616689ae34ff6a902faba (patch)
tree383c8a010d1dc8a2a6a6bda0467f52507b91d9d7 /drivers
parent98c7355fb373d7c29e5c45d0a423810ad2476b34 (diff)
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/i2c/busses/i2c-cpm.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-cpm.c b/drivers/i2c/busses/i2c-cpm.c
index 3823623baa4..9e600210872 100644
--- a/drivers/i2c/busses/i2c-cpm.c
+++ b/drivers/i2c/busses/i2c-cpm.c
@@ -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);