Title: [9012] branches/2009R1/drivers/i2c/busses/i2c-bfin-twi.c: [#6136] Illegal i2c bus lock upon certain transfer scenarios
- Revision
- 9012
- Author
- hennerich
- Date
- 2010-07-23 04:25:03 -0400 (Fri, 23 Jul 2010)
Log Message
[#6136] Illegal i2c bus lock upon certain transfer scenarios
For transfer counts > 255 bytes i2c-bfin-twi sets the data
transfer counter DCNT to 0xFF indicating unlimited transfers.
It then uses a flag iface->manual_stop to manually issue the STOP
condition, once the required amount of bytes are received.
We found that on I2C receive operation issuing the STOP condition
together with a FULL RCV FIFO (2bytes) will cause SDA and SCL be
constantly driven low.
Temporary workaround until further investigation:
Discard the RCV FIFO before issuing the STOP condition.
Modified Paths
Diff
Modified: branches/2009R1/drivers/i2c/busses/i2c-bfin-twi.c (9011 => 9012)
--- branches/2009R1/drivers/i2c/busses/i2c-bfin-twi.c 2010-07-23 08:23:05 UTC (rev 9011)
+++ branches/2009R1/drivers/i2c/busses/i2c-bfin-twi.c 2010-07-23 08:25:03 UTC (rev 9012)
@@ -129,6 +129,10 @@
iface->transPtr++;
iface->readNum--;
} else if (iface->manual_stop) {
+ /* Avoid possible bus stall -
+ * Flush FIFO before issuing the STOP condition
+ */
+ read_RCV_DATA16(iface);
write_MASTER_CTL(iface,
read_MASTER_CTL(iface) | STOP);
} else if (iface->cur_mode == TWI_I2C_MODE_REPEAT &&
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